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Antonioni A, Raho EM, Straudi S, Granieri E, Koch G, Fadiga L. The cerebellum and the Mirror Neuron System: A matter of inhibition? From neurophysiological evidence to neuromodulatory implications. A narrative review. Neurosci Biobehav Rev 2024; 164:105830. [PMID: 39069236 DOI: 10.1016/j.neubiorev.2024.105830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2024] [Revised: 07/20/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Mirror neurons show activity during both the execution (AE) and observation of actions (AO). The Mirror Neuron System (MNS) could be involved during motor imagery (MI) as well. Extensive research suggests that the cerebellum is interconnected with the MNS and may be critically involved in its activities. We gathered evidence on the cerebellum's role in MNS functions, both theoretically and experimentally. Evidence shows that the cerebellum plays a major role during AO and MI and that its lesions impair MNS functions likely because, by modulating the activity of cortical inhibitory interneurons with mirror properties, the cerebellum may contribute to visuomotor matching, which is fundamental for shaping mirror properties. Indeed, the cerebellum may strengthen sensory-motor patterns that minimise the discrepancy between predicted and actual outcome, both during AE and AO. Furthermore, through its connections with the hippocampus, the cerebellum might be involved in internal simulations of motor programs during MI. Finally, as cerebellar neuromodulation might improve its impact on MNS activity, we explored its potential neurophysiological and neurorehabilitation implications.
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Affiliation(s)
- Annibale Antonioni
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara 44121, Italy; Department of Neuroscience, Ferrara University Hospital, Ferrara 44124, Italy; Doctoral Program in Translational Neurosciences and Neurotechnologies, University of Ferrara, Ferrara 44121, Italy.
| | - Emanuela Maria Raho
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara 44121, Italy
| | - Sofia Straudi
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara 44121, Italy; Department of Neuroscience, Ferrara University Hospital, Ferrara 44124, Italy
| | - Enrico Granieri
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara 44121, Italy
| | - Giacomo Koch
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara 44121, Italy; Center for Translational Neurophysiology of Speech and Communication (CTNSC), Italian Institute of Technology (IIT), Ferrara 44121 , Italy; Non Invasive Brain Stimulation Unit, Istituto di Ricovero e Cura a Carattere Scientifico Santa Lucia, Rome 00179, Italy
| | - Luciano Fadiga
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara 44121, Italy; Center for Translational Neurophysiology of Speech and Communication (CTNSC), Italian Institute of Technology (IIT), Ferrara 44121 , Italy
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Mitsuhashi M, Yamaguchi R, Kawasaki T, Ueno S, Sun Y, Isa K, Takahashi J, Kobayashi K, Onoe H, Takahashi R, Isa T. Stage-dependent role of interhemispheric pathway for motor recovery in primates. Nat Commun 2024; 15:6762. [PMID: 39174504 PMCID: PMC11341697 DOI: 10.1038/s41467-024-51070-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 07/26/2024] [Indexed: 08/24/2024] Open
Abstract
Whether and how the non-lesional sensorimotor cortex is activated and contributes to post-injury motor recovery is controversial. Here, we investigated the role of interhemispheric pathway from the contralesional to ipsilesional premotor cortex in activating the ipsilesional sensorimotor cortex and promoting recovery after lesioning the lateral corticospinal tract at the cervical cord, by unidirectional chemogenetic blockade in macaques. The blockade impaired dexterous hand movements during the early recovery stage. Electrocorticographical recording showed that the low frequency band activity of the ipsilesional premotor cortex around movement onset was decreased by the blockade during the early recovery stage, while it was increased by blockade during the intact state and late recovery stage. These results demonstrate that action of the interhemispheric pathway changed from inhibition to facilitation, to involve the ipsilesional sensorimotor cortex in hand movements during the early recovery stage. The present study offers insights into the stage-dependent role of the interhemispheric pathway and a therapeutic target in the early recovery stage after lesioning of the corticospinal tract.
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Affiliation(s)
- Masahiro Mitsuhashi
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Reona Yamaguchi
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, 606-8501, Japan
| | - Toshinari Kawasaki
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Satoko Ueno
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, 606-8501, Japan
| | - Yiping Sun
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Kaoru Isa
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Jun Takahashi
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, 606-8507, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, 444-8585, Japan
- Graduate University of Advanced Studies (SOKENDAI), Hayama, 240-0193, Japan
| | - Hirotaka Onoe
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, 606-8397, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Tadashi Isa
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan.
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, 606-8501, Japan.
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, 606-8397, Japan.
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Jia F, Zhao Y, Wang Z, Chen J, Lu S, Zhang M. Effect of Graded Motor Imagery Combined With Repetitive Transcranial Magnetic Stimulation on Upper Extremity Motor Function in Stroke Patients: A Randomized Controlled Trial. Arch Phys Med Rehabil 2024; 105:819-825. [PMID: 38110138 DOI: 10.1016/j.apmr.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 11/28/2023] [Accepted: 12/03/2023] [Indexed: 12/20/2023]
Abstract
OBJECTIVE To investigate the efficacy of graded motor imagery therapy (GMI) and repetitive transcranial magnetic stimulation (rTMS) on upper extremity function alone and in combination in patients with stroke. DESIGN This was a prospective randomized controlled trial. SETTING A rehabilitation hospital. PARTICIPANTS Participants (N=56) were randomized into GMI (n=19), rTMS (n=18), or combined groups (n=19). INTERVENTIONS There were 2 interventions: (1) 20 minutes of 1 Hz rTMS. (2) 30 minutes of GMI. In addition to this, all participants receive conventional rehabilitation including 120 minutes of physical therapy and occupational therapy daily. All treatments were administered once a day, 5 days a week, for 4 weeks. The Fugl-Meyer assessment of upper extremity (FMA-UE), Action Research Arm Test (ARAT), modified Barthel Index (MBI), motor activity log (MAL), and motor evoked potential (MEP) were assessed in a blinded manner at baseline and 4 weeks after treatment, respectively. MAIN OUTCOME MEASURES The primary endpoint was the improvement from baseline in FMA-UE for stroke patients at 4 weeks. RESULTS After 4 weeks of treatment, the FMA-UE scores in the GMI, rTMS, and combined groups were higher than those at baseline assessment, with statistically significant differences among the 3 groups (P=.009). The efficacy of the combined group was significantly better than that of the GMI and rTMS groups (P=.015, P=.043, respectively). In the motor activity log-amount of use (MAL-AOU) score, the efficacy of the combined group was better than that of the rTMS group (P=.035). CONCLUSIONS Both GMI and rTMS were effective in improving upper extremity function in patients with stroke, but the combination of the 2 techniques was more effective. However, GMI was better than rTMS in improving the interest of stroke patients in active training.
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Affiliation(s)
- Fan Jia
- Xuzhou Rehabilitation Hospital affiliated with Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Ying Zhao
- Xuzhou Rehabilitation Hospital affiliated with Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zhao Wang
- Xuzhou Rehabilitation Hospital affiliated with Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jie Chen
- Xuzhou Rehabilitation Hospital affiliated with Xuzhou Medical University, Xuzhou, Jiangsu, China; Department of Rehabilitation Medicine of Xuzhou Central Hospital, Xuzhou, Jiangsu, China
| | - Sihan Lu
- Xuzhou Rehabilitation Hospital affiliated with Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Ming Zhang
- Xuzhou Rehabilitation Hospital affiliated with Xuzhou Medical University, Xuzhou, Jiangsu, China; Department of Rehabilitation Medicine of Xuzhou Central Hospital, Xuzhou, Jiangsu, China.
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Lv Y, Zhang JJ, Wang K, Ju L, Zhang H, Zhao Y, Pan Y, Gong J, Wang X, Fong KNK. Determining the Optimal Stimulation Sessions for TMS-Induced Recovery of Upper Extremity Motor Function Post Stroke: A Randomized Controlled Trial. Brain Sci 2023; 13:1662. [PMID: 38137110 PMCID: PMC10741851 DOI: 10.3390/brainsci13121662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
To find out the optimal treatment sessions of repetitive transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) for upper extremity dysfunction after stroke during the 6-week treatment and to explore its mechanism using motor-evoked potentials (MEPs) and resting-state functional magnetic resonance imaging (rs-fMRI), 72 participants with upper extremity motor dysfunction after ischemic stroke were randomly divided into the control group, 10-session, 20-session, and 30-session rTMS groups. Low-frequency (1 Hz) rTMS over the contralesional M1 was applied in all rTMS groups. The motor function of the upper extremity was assessed before and after treatment. In addition, MEPs and rs-fMRI data were analyzed to detect its effect on brain reorganization. After 6 weeks of treatment, there were significant differences in the Fugl-Meyer Assessment of the upper extremity and the Wolf Motor Function Test scores between the 10-session group and the 30-session group and between the 20- and 30-session groups and the control group, while there was no significant difference between the 20-session group and the 30-session group. Meanwhile, no significant difference was found between the 10-session group and the control group. The 20-session group of rTMS decreased the excitability of the contralesional corticospinal tract represented by the amplitudes of MEPs and enhanced the functional connectivity of the ipsilesional M1 or premotor cortex with the the precentral gyrus, postcentral gyrus, and cingulate gyrus, etc. In conclusion, the 20-session of rTMS protocol is the optimal treatment sessions of TMS for upper extremity dysfunction after stroke during the 6-week treatment. The potential mechanism is related to its influence on the excitability of the corticospinal tract and the remodeling of corticomotor functional networks.
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Affiliation(s)
- Yichen Lv
- School of Rehabilitation Medicine, Binzhou Medical University, Yantai 264000, China
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Jack Jiaqi Zhang
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Kui Wang
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Leilei Ju
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Hongying Zhang
- Department of Medical Imaging, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Yuehan Zhao
- School of Rehabilitation Medicine, Binzhou Medical University, Yantai 264000, China
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Yao Pan
- School of Rehabilitation Medicine, Binzhou Medical University, Yantai 264000, China
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Jianwei Gong
- School of Rehabilitation Medicine, Binzhou Medical University, Yantai 264000, China
| | - Xin Wang
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Kenneth N. K. Fong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
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Depolarization and Hyperexcitability of Cortical Motor Neurons after Spinal Cord Injury Associates with Reduced HCN Channel Activity. Int J Mol Sci 2023; 24:ijms24054715. [PMID: 36902146 PMCID: PMC10003573 DOI: 10.3390/ijms24054715] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/05/2023] Open
Abstract
A spinal cord injury (SCI) damages the axonal projections of neurons residing in the neocortex. This axotomy changes cortical excitability and results in dysfunctional activity and output of infragranular cortical layers. Thus, addressing cortical pathophysiology after SCI will be instrumental in promoting recovery. However, the cellular and molecular mechanisms of cortical dysfunction after SCI are poorly resolved. In this study, we determined that the principal neurons of the primary motor cortex layer V (M1LV), those suffering from axotomy upon SCI, become hyperexcitable following injury. Therefore, we questioned the role of hyperpolarization cyclic nucleotide gated channels (HCN channels) in this context. Patch clamp experiments on axotomized M1LV neurons and acute pharmacological manipulation of HCN channels allowed us to resolve a dysfunctional mechanism controlling intrinsic neuronal excitability one week after SCI. Some axotomized M1LV neurons became excessively depolarized. In those cells, the HCN channels were less active and less relevant to control neuronal excitability because the membrane potential exceeded the window of HCN channel activation. Care should be taken when manipulating HCN channels pharmacologically after SCI. Even though the dysfunction of HCN channels partakes in the pathophysiology of axotomized M1LV neurons, their dysfunctional contribution varies remarkably between neurons and combines with other pathophysiological mechanisms.
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Zhang JJ, Sánchez Vidaña DI, Chan JNM, Hui ESK, Lau KK, Wang X, Lau BWM, Fong KNK. Biomarkers for prognostic functional recovery poststroke: A narrative review. Front Cell Dev Biol 2023; 10:1062807. [PMID: 36699006 PMCID: PMC9868572 DOI: 10.3389/fcell.2022.1062807] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/19/2022] [Indexed: 01/11/2023] Open
Abstract
Background and objective: Prediction of poststroke recovery can be expressed by prognostic biomarkers that are related to the pathophysiology of stroke at the cellular and molecular level as well as to the brain structural and functional reserve after stroke at the systems neuroscience level. This study aimed to review potential biomarkers that can predict poststroke functional recovery. Methods: A narrative review was conducted to qualitatively summarize the current evidence on biomarkers used to predict poststroke functional recovery. Results: Neurophysiological measurements and neuroimaging of the brain and a wide diversity of molecules had been used as prognostic biomarkers to predict stroke recovery. Neurophysiological studies using resting-state electroencephalography (EEG) revealed an interhemispheric asymmetry, driven by an increase in low-frequency oscillation and a decrease in high-frequency oscillation in the ipsilesional hemisphere relative to the contralesional side, which was indicative of individual recovery potential. The magnitude of somatosensory evoked potentials and event-related desynchronization elicited by movement in task-related EEG was positively associated with the quantity of recovery. Besides, transcranial magnetic stimulation (TMS) studies revealed the potential values of using motor-evoked potentials (MEP) and TMS-evoked EEG potentials from the ipsilesional motor cortex as prognostic biomarkers. Brain structures measured using magnetic resonance imaging (MRI) have been implicated in stroke outcome prediction. Specifically, the damage to the corticospinal tract (CST) and anatomical motor connections disrupted by stroke lesion predicted motor recovery. In addition, a wide variety of molecular, genetic, and epigenetic biomarkers, including hemostasis, inflammation, tissue remodeling, apoptosis, oxidative stress, infection, metabolism, brain-derived, neuroendocrine, and cardiac biomarkers, etc., were associated with poor functional outcomes after stroke. However, challenges such as mixed evidence and analytical concerns such as specificity and sensitivity have to be addressed before including molecular biomarkers in routine clinical practice. Conclusion: Potential biomarkers with prognostic values for the prediction of functional recovery after stroke have been identified; however, a multimodal approach of biomarkers for prognostic prediction has rarely been studied in the literature. Future studies may incorporate a combination of multiple biomarkers from big data and develop algorithms using data mining methods to predict the recovery potential of patients after stroke in a more precise way.
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Affiliation(s)
- Jack Jiaqi Zhang
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | | | - Jackie Ngai-Man Chan
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Edward S. K. Hui
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
- Department of Psychiatry, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Kui Kai Lau
- Division of Neurology, Department of Medicine, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Xin Wang
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou, China
| | - Benson W. M. Lau
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Kenneth N. K. Fong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
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Yasaroglu S, Liepert J. Transcranial direct current stimulation in stroke - Motor excitability and motor function. Clin Neurophysiol 2022; 144:16-22. [PMID: 36208617 DOI: 10.1016/j.clinph.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/28/2022] [Accepted: 09/08/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To characterize motor excitability changes and changes of motor performance induced by a single anodal and cathodal transcranial direct current stimulation (tDCS) session in stroke patients. METHODS Twenty subacute stroke patients participated. Motor performance was tested with the Box and Block Test [BBT]. Motor cortex excitability (short interval intracortical inhibition [SICI], intracortical facilitation [ICF], long interval intracortical inhibition [LICI]) was examined by paired pulse transcranial magnetic stimulation before and after a single tDCS session (20 minutes, 1,0 mA). On two different occasions, patients received anodal and cathodal tDCS over the affected hemisphere. TMS recordings were taken from both hands consecutively. RESULTS Anodal tDCS significantly reduced SICI without changing ICF or LICI. Cathodal tDCS did not change motor excitability. Both types of tDCS did not alter motor performance. Even prior to anodal tDCS, SICI in the affected hemisphere was lower than in the unaffected hemisphere and was correlated with BBT changes after anodal tDCS. CONCLUSIONS Anodal, but not cathodal tDCS specifically modulated intracortical inhibitory circuits, leading to a disinhibition. SIGNIFICANCE The results amplify our knowledge on excitability modulations of tDCS in stroke patients.
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Benedetti B, Weidenhammer A, Reisinger M, Couillard-Despres S. Spinal Cord Injury and Loss of Cortical Inhibition. Int J Mol Sci 2022; 23:5622. [PMID: 35628434 PMCID: PMC9144195 DOI: 10.3390/ijms23105622] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023] Open
Abstract
After spinal cord injury (SCI), the destruction of spinal parenchyma causes permanent deficits in motor functions, which correlates with the severity and location of the lesion. Despite being disconnected from their targets, most cortical motor neurons survive the acute phase of SCI, and these neurons can therefore be a resource for functional recovery, provided that they are properly reconnected and retuned to a physiological state. However, inappropriate re-integration of cortical neurons or aberrant activity of corticospinal networks may worsen the long-term outcomes of SCI. In this review, we revisit recent studies addressing the relation between cortical disinhibition and functional recovery after SCI. Evidence suggests that cortical disinhibition can be either beneficial or detrimental in a context-dependent manner. A careful examination of clinical data helps to resolve apparent paradoxes and explain the heterogeneity of treatment outcomes. Additionally, evidence gained from SCI animal models indicates probable mechanisms mediating cortical disinhibition. Understanding the mechanisms and dynamics of cortical disinhibition is a prerequisite to improve current interventions through targeted pharmacological and/or rehabilitative interventions following SCI.
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Affiliation(s)
- Bruno Benedetti
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Annika Weidenhammer
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Maximilian Reisinger
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Sebastien Couillard-Despres
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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Zhang JJ, Bai Z, Fong KNK. Priming Intermittent Theta Burst Stimulation for Hemiparetic Upper Limb After Stroke: A Randomized Controlled Trial. Stroke 2022; 53:2171-2181. [PMID: 35317611 DOI: 10.1161/strokeaha.121.037870] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Intermittent theta burst stimulation (iTBS) creates a state with increased excitability that permits treatment modalities to induce neuroplasticity and motor learning. Continuous theta burst stimulation before iTBS may induce metaplasticity and boost the facilitatory effect of iTBS. This study investigated the effects of priming iTBS (ie, applying continuous theta burst stimulation before iTBS) on poststroke hemiparetic upper limb recovery. METHODS In this randomized controlled trial, 42 patients with chronic stroke were recruited and randomly allocated to 10 sessions of either priming iTBS, nonpriming iTBS, or sham stimulation to the ipsilesional motor cortex, immediately before robot-assisted training. Outcomes included Fugl-Meyer Assessment-Upper Extremity, Action Research Arm Test and mean movement velocity during each robot-assisted training session. Twenty-one patients were enrolled for measuring the sensorimotor beta event-related desynchronization induced by either mirror visual feedback or movement. RESULTS The Fugl-Meyer Assessment-Upper Extremity scores revealed a significant time-by-group interaction (P=0.011). Priming and nonpriming iTBS were both superior to sham stimulation in post hoc comparisons; however, the superiority was diminished at follow-up. Among patients with a higher functioning upper limb, priming iTBS yielded a significantly greater improvement in Fugl-Meyer Assessment-Upper Extremity scores than nonpriming iTBS (P=0.025) and sham stimulation (P=0.029) did. No significant interaction was found when analyzing the Action Research Arm Test and mean movement velocity. Priming iTBS enhanced the patients' mirror visual feedback-induced high beta sensorimotor event-related desynchronization over their ipsilesional hemisphere. CONCLUSIONS Priming and nonpriming iTBS are both superior to sham stimulation in enhancing treatment gains from robot-assisted training, and patients with a higher functioning upper limb may experience more benefits from priming iTBS. Priming iTBS may facilitate poststroke motor learning by enhancing the permissiveness of the ipsilesional sensorimotor area to therapeutic sensory modalities, such as the mirror visual feedback. REGISTRATION URL: https://www. CLINICALTRIALS gov; Unique identifier: NCT04034069.
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Affiliation(s)
- Jack Jiaqi Zhang
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR (J.J.Z., Z.B., K.N.K.F.)
| | - Zhongfei Bai
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR (J.J.Z., Z.B., K.N.K.F.).,Department of Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Tongji University, China (Z.B.)
| | - Kenneth N K Fong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR (J.J.Z., Z.B., K.N.K.F.)
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Otaki R, Oouchida Y, Aizu N, Sudo T, Sasahara H, Saito Y, Takemura S, Izumi SI. Relationship Between Body-Specific Attention to a Paretic Limb and Real-World Arm Use in Stroke Patients: A Longitudinal Study. Front Syst Neurosci 2022; 15:806257. [PMID: 35273480 PMCID: PMC8902799 DOI: 10.3389/fnsys.2021.806257] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/21/2021] [Indexed: 11/13/2022] Open
Abstract
Learned nonuse is a major problem in upper limb (UL) rehabilitation after stroke. Among the various factors that contribute to learned nonuse, recent studies have focused on body representation of the paretic limb in the brain. We previously developed a method to measure body-specific attention, as a marker of body representation of the paretic limb and revealed a decline in body-specific attention to the paretic limb in chronic stroke patients by a cross-sectional study. However, longitudinal changes in body-specific attention and paretic arm use in daily life (real-world arm use) from the onset to the chronic phase, and their relationship, remain unknown. Here, in a longitudinal, prospective, observational study, we sought to elucidate the longitudinal changes in body-specific attention to the paretic limb and real-world arm use, and their relationship, by using accelerometers and psychophysical methods, respectively, in 25 patients with subacute stroke. Measurements were taken at baseline (TBL), 2 weeks (T2w), 1 month (T1M), 2 months (T2M), and 6 months (T6M) after enrollment. UL function was measured using the Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT). Real-world arm use was measured using accelerometers on both wrists. Body-specific attention was measured using a visual detection task. The UL function and real-world arm use improved up to T6M. Longitudinal changes in body-specific attention were most remarkable at T1M. Changes in body-specific attention up to T1M correlated positively with changes in real-world arm use up to T6M, and from T1M to T6M, and the latter more strongly correlated with changes in real-world arm use. Changes in real-world arm use up to T2M correlated positively with changes in FMA up to T2M and T6M. No correlation was found between body-specific attention and FMA scores. Thus, these results suggest that improved body-specific attention to the paretic limb during the early phase contributes to increasing long-term real-world arm use and that increased real-world use is associated with the recovery of UL function. Our results may contribute to the development of rehabilitation strategies to enhance adaptive changes in body representation in the brain and increase real-world arm use after stroke.
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Affiliation(s)
- Ryoji Otaki
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Rehabilitation, Yamagata Saisei Hospital, Yamagata, Japan
| | - Yutaka Oouchida
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Education, Osaka Kyoiku University, Osaka, Japan
| | - Naoki Aizu
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Faculty of Rehabilitation, School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Tamami Sudo
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Computer and Information Sciences, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hiroshi Sasahara
- Department of Rehabilitation, Yamagata Saisei Hospital, Yamagata, Japan
| | - Yuki Saito
- Department of Neurosurgery, Yamagata Saisei Hospital, Yamagata, Japan
| | - Sunao Takemura
- Department of Neurosurgery, Yamagata Saisei Hospital, Yamagata, Japan
| | - Shin-Ichi Izumi
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
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11
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King JT, John AR, Wang YK, Shih CK, Zhang D, Huang KC, Lin CT. Brain Connectivity Changes During Bimanual and Rotated Motor Imagery. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE 2022; 10:2100408. [PMID: 35492507 PMCID: PMC9041539 DOI: 10.1109/jtehm.2022.3167552] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 01/24/2022] [Accepted: 04/03/2022] [Indexed: 11/10/2022]
Abstract
Motor imagery-based brain-computer interface (MI-BCI) currently represents a new trend in rehabilitation. However, individual differences in the responsive frequency bands and a poor understanding of the communication between the ipsilesional motor areas and other regions limit the use of MI-BCI therapy. Objective: Bimanual training has recently attracted attention as it achieves better outcomes as compared to repetitive one-handed training. This study compared the effects of three MI tasks with different visual feedback. Methods: Fourteen healthy subjects performed single hand motor imagery tasks while watching single static hand (traditional MI), single hand with rotation movement (rmMI), and bimanual coordination with a hand pedal exerciser (bcMI). Functional connectivity is estimated by Transfer Entropy (TE) analysis for brain information flow. Results: Brain connectivity of conducting three MI tasks showed that the bcMI demonstrated increased communications from the parietal to the bilateral prefrontal areas and increased contralateral connections between motor-related zones and spatial processing regions. Discussion/Conclusion: The results revealed bimanual coordination operation events increased spatial information and motor planning under the motor imagery task. And the proposed bimanual coordination MI-BCI (bcMI-BCI) can also achieve the effect of traditional motor imagery tasks and promotes more effective connections with different brain regions to better integrate motor-cortex functions for aiding the development of more effective MI-BCI therapy. Clinical and Translational Impact Statement The proposed bcMI-BCI provides more effective connections with different brain areas and integrates motor-cortex functions to promote motor imagery rehabilitation for patients’ impairment.
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Affiliation(s)
- Jung-Tai King
- Brain Research Center, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Alka Rachel John
- CIBCI Laboratory, Australian AI Institute, FEIT, University of Technology Sydney, Ultimo, NSW, Australia
| | - Yu-Kai Wang
- CIBCI Laboratory, Australian AI Institute, FEIT, University of Technology Sydney, Ultimo, NSW, Australia
| | - Chun-Kai Shih
- Brain Research Center, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Dingguo Zhang
- Department of Electronic and Electrical Engineering, University of Bath, Bath, U.K
| | - Kuan-Chih Huang
- Brain Research Center, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Chin-Teng Lin
- Brain Research Center, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
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12
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Acker G, Giampiccolo D, Rubarth K, Mertens R, Zdunczyk A, Hardt J, Jussen D, Schneider H, Rosenstock T, Mueller V, Picht T, Vajkoczy P. Motor excitability in bilateral moyamoya vasculopathy and the impact of revascularization. Neurosurg Focus 2021; 51:E7. [PMID: 34469868 DOI: 10.3171/2021.6.focus21280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/23/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Motor cortical dysfunction has been shown to be reversible in patients with unilateral atherosclerotic disease after cerebral revascularization. Moyamoya vasculopathy (MMV) is a rare bilateral stenoocclusive cerebrovascular disease. The aim of this study was to analyze the corticospinal excitability and the role of bypass surgery in restoring cortical motor function in patients by using navigated transcranial magnetic stimulation (nTMS). METHODS Patients with bilateral MMV who met the criteria for cerebral revascularization were prospectively included. Corticospinal excitability, cortical representation area, and intracortical inhibition and facilitation were assessed by nTMS for a small hand muscle (first dorsal interosseous) before and after revascularization. The clinically and/or hemodynamically more severely affected hemisphere was operated first as the leading hemisphere. Intra- and interhemispheric differences were analyzed before and after direct or combined revascularization. RESULTS A total of 30 patients with bilateral MMV were examined by nTMS prior to and after revascularization surgery. The corticospinal excitability was higher in the leading hemisphere compared with the non-leading hemisphere prior to revascularization. This hyperexcitability was normalized after revascularization as demonstrated in the resting motor threshold ratio of the hemispheres (preoperative median 0.97 [IQR 0.89-1.08], postoperative median 1.02 [IQR 0.94-1.22]; relative effect = 0.61, p = 0.03). In paired-pulse paradigms, a tendency for a weaker inhibition of the leading hemisphere was observed compared with the non-leading hemisphere. Importantly, the paired paradigm also demonstrated approximation of excitability patterns between the two hemispheres after surgery. CONCLUSIONS The study results suggested that, in the case of a bilateral chronic ischemia, a compensation mechanism between both hemispheres seemed to exist that normalized after revascularization surgery. A potential role of nTMS in predicting the efficacy of revascularization must be further assessed.
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Affiliation(s)
- Gueliz Acker
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin.,2Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin
| | - Davide Giampiccolo
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Kerstin Rubarth
- 2Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin.,3Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biometry and Clinical Epidemiology, Berlin
| | - Robert Mertens
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Anna Zdunczyk
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Juliane Hardt
- 3Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biometry and Clinical Epidemiology, Berlin.,4University of Applied Sciences Hannover, Hochschule Hannover-University of Applied Sciences and Arts, Fakultät III, Department Information and Communication, Medical Information Management, Hannover.,5Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health in the Human-Animal-Environment Interface, University of Veterinary Medicine Hannover, Foundation, Hannover; and
| | - Daniel Jussen
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Heike Schneider
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Tizian Rosenstock
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin.,2Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin
| | - Vera Mueller
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Thomas Picht
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin.,6Cluster of Excellence: "Matters of Activity. Image Space Material," Humboldt University, Berlin, Germany
| | - Peter Vajkoczy
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
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13
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Betancur DFA, Tarragó MDGL, Torres ILDS, Fregni F, Caumo W. Central Post-Stroke Pain: An Integrative Review of Somatotopic Damage, Clinical Symptoms, and Neurophysiological Measures. Front Neurol 2021; 12:678198. [PMID: 34484097 PMCID: PMC8416310 DOI: 10.3389/fneur.2021.678198] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 07/02/2021] [Indexed: 01/26/2023] Open
Abstract
Introduction: The physiopathology of central post-stroke pain (CPSP) is poorly understood, which may contribute to the limitations of diagnostic and therapeutic advancements. Thus, the current systematic review was conducted to examine, from an integrated perspective, the cortical neurophysiological changes observed via transcranial magnetic stimulation (TMS), focusing on the structural damage, and clinical symptoms in patients with CPSP. Methods: The literature review included the databases EMBASE, PubMed, and ScienceDirect using the following search terms by MeSH or Entree descriptors: [("Cerebral Stroke") AND ("Pain" OR "Transcranial Magnetic Stimulation") AND ("Transcranial Magnetic Stimulation")] (through September 29, 2020). A total of 297 articles related to CPSP were identified. Of these, only four quantitatively recorded cortical measurements. Results: We found four studies with different methodologies and results of the TMS measures. According to the National Institutes of Health (NIH) guidelines, two studies had low methodological quality and the other two studies had satisfactory methodological quality. The four studies compared the motor threshold (MT) of the stroke-affected hemisphere with the unaffected hemisphere or with healthy controls. Two studies assessed other cortical excitability measures, such as cortical silent period (CSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF). The main limitations in the interpretation of the results were the heterogeneity in parameter measurements, unknown cortical excitability measures as potential prognostic markers, the lack of a control group without pain, and the absence of consistent and validated diagnosis criteria. Conclusion: Despite the limited number of studies that prevented us from conducting a meta-analysis, the dataset of this systematic review provides evidence to improve the understanding of CPSP physiopathology. Additionally, these studies support the construction of a framework for diagnosis and will help improve the methodological quality of future research in somatosensory sequelae following stroke. Furthermore, they offer a way to integrate dysfunctional neuroplasticity markers that are indirectly assessed by neurophysiological measures with their correlated clinical symptoms.
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Affiliation(s)
- Daniel Fernando Arias Betancur
- Graduate Program in Medical Sciences, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Laboratory of Pain & Neuromodulation, Clinical Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | | | - Iraci Lucena da Silva Torres
- Graduate Program in Medical Sciences, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Pharmacology of Pain and Neuromodulation: Pre-clinical Investigations Research Group, Federal University of Rio Grande Do Sul (UFRGS), Porto Alegre, Brazil
| | - Felipe Fregni
- Laboratory of Neuromodulation and Center for Clinical Research Learning, Physics, and Rehabilitation Department, Spaulding Rehabilitation Hospital, Boston, MA, United States
| | - Wolnei Caumo
- Graduate Program in Medical Sciences, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Laboratory of Pain & Neuromodulation, Clinical Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
- Pain and Palliative Care Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
- Department of Surgery, School of Medicine, Federal University of Rio Grande Do Sul (UFRGS), Porto Alegre, Brazil
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14
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Hu M, Cheng HJ, Ji F, Chong JSX, Lu Z, Huang W, Ang KK, Phua KS, Chuang KH, Jiang X, Chew E, Guan C, Zhou JH. Brain Functional Changes in Stroke Following Rehabilitation Using Brain-Computer Interface-Assisted Motor Imagery With and Without tDCS: A Pilot Study. Front Hum Neurosci 2021; 15:692304. [PMID: 34335210 PMCID: PMC8322606 DOI: 10.3389/fnhum.2021.692304] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/24/2021] [Indexed: 11/13/2022] Open
Abstract
Brain-computer interface-assisted motor imagery (MI-BCI) or transcranial direct current stimulation (tDCS) has been proven effective in post-stroke motor function enhancement, yet whether the combination of MI-BCI and tDCS may further benefit the rehabilitation of motor functions remains unknown. This study investigated brain functional activity and connectivity changes after a 2 week MI-BCI and tDCS combined intervention in 19 chronic subcortical stroke patients. Patients were randomized into MI-BCI with tDCS group and MI-BCI only group who underwent 10 sessions of 20 min real or sham tDCS followed by 1 h MI-BCI training with robotic feedback. We derived amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and functional connectivity (FC) from resting-state functional magnetic resonance imaging (fMRI) data pre- and post-intervention. At baseline, stroke patients had lower ALFF in the ipsilesional somatomotor network (SMN), lower ReHo in the contralesional insula, and higher ALFF/Reho in the bilateral posterior default mode network (DMN) compared to age-matched healthy controls. After the intervention, the MI-BCI only group showed increased ALFF in contralesional SMN and decreased ALFF/Reho in the posterior DMN. In contrast, no post-intervention changes were detected in the MI-BCI + tDCS group. Furthermore, higher increases in ALFF/ReHo/FC measures were related to better motor function recovery (measured by the Fugl-Meyer Assessment scores) in the MI-BCI group while the opposite association was detected in the MI-BCI + tDCS group. Taken together, our findings suggest that brain functional re-normalization and network-specific compensation were found in the MI-BCI only group but not in the MI-BCI + tDCS group although both groups gained significant motor function improvement post-intervention with no group difference. MI-BCI and tDCS may exert differential or even opposing impact on brain functional reorganization during post-stroke motor rehabilitation; therefore, the integration of the two strategies requires further refinement to improve efficacy and effectiveness.
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Affiliation(s)
- Mengjiao Hu
- NTU Institute for Health Technologies, Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore, Singapore.,Center for Sleep and Cognition, Center for Translational MR Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hsiao-Ju Cheng
- Center for Sleep and Cognition, Center for Translational MR Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore
| | - Fang Ji
- Center for Sleep and Cognition, Center for Translational MR Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Joanna Su Xian Chong
- Center for Sleep and Cognition, Center for Translational MR Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Zhongkang Lu
- Institute for Infocomm Research, Agency for Science Technology and Research, Singapore, Singapore
| | - Weimin Huang
- Institute for Infocomm Research, Agency for Science Technology and Research, Singapore, Singapore
| | - Kai Keng Ang
- Institute for Infocomm Research, Agency for Science Technology and Research, Singapore, Singapore.,School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Kok Soon Phua
- Institute for Infocomm Research, Agency for Science Technology and Research, Singapore, Singapore
| | - Kai-Hsiang Chuang
- Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore, Singapore.,Queensland Brain Institute and Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia
| | - Xudong Jiang
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Effie Chew
- Division of Neurology, University Medicine Cluster, National University Health System, Singapore, Singapore
| | - Cuntai Guan
- School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Juan Helen Zhou
- Center for Sleep and Cognition, Center for Translational MR Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.,Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore
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15
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Hordacre B, Austin D, Brown KE, Graetz L, Parees I, De Trane S, Vallence AM, Koblar S, Kleinig T, McDonnell MN, Greenwood R, Ridding MC, Rothwell JC. Evidence for a Window of Enhanced Plasticity in the Human Motor Cortex Following Ischemic Stroke. Neurorehabil Neural Repair 2021; 35:307-320. [PMID: 33576318 PMCID: PMC7610679 DOI: 10.1177/1545968321992330] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND In preclinical models, behavioral training early after stroke produces larger gains compared with delayed training. The effects are thought to be mediated by increased and widespread reorganization of synaptic connections in the brain. It is viewed as a period of spontaneous biological recovery during which synaptic plasticity is increased. OBJECTIVE To look for evidence of a similar change in synaptic plasticity in the human brain in the weeks and months after ischemic stroke. METHODS We used continuous theta burst stimulation (cTBS) to activate synapses repeatedly in the motor cortex. This initiates early stages of synaptic plasticity that temporarily reduces cortical excitability and motor-evoked potential amplitude. Thus, the greater the effect of cTBS on the motor-evoked potential, the greater the inferred level of synaptic plasticity. Data were collected from separate cohorts (Australia and UK). In each cohort, serial measurements were made in the weeks to months following stroke. Data were obtained for the ipsilesional motor cortex in 31 stroke survivors (Australia, 66.6 ± 17.8 years) over 12 months and the contralesional motor cortex in 29 stroke survivors (UK, 68.2 ± 9.8 years) over 6 months. RESULTS Depression of cortical excitability by cTBS was most prominent shortly after stroke in the contralesional hemisphere and diminished over subsequent sessions (P = .030). cTBS response did not differ across the 12-month follow-up period in the ipsilesional hemisphere (P = .903). CONCLUSIONS Our results provide the first neurophysiological evidence consistent with a period of enhanced synaptic plasticity in the human brain after stroke. Behavioral training given during this period may be especially effective in supporting poststroke recovery.
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Affiliation(s)
- Brenton Hordacre
- University of South Australia, IIMPACT in Health, Adelaide,
Australia
| | - Duncan Austin
- UCL Institute of Neurology, Queen Square, London, UK
| | | | - Lynton Graetz
- Lifespan Human Neurophysiology group, Adelaide Medical
School, The University of Adelaide, Australia
| | - Isabel Parees
- Servicio de Neurologia, Hospital Universitario Ramón
y Cajal, Madrid, Spain
- Servicio de Neurología, Hospital Ruber
Internacional, Madrid, Spain
| | - Stefania De Trane
- The Blizard Institute, Barts and The London School of
Medicine & Dentistry, Queen Mary University of London, London, UK
- Clinical Board: Medicine (Neuroscience), The Royal London
Hospital, Barts Health NHS Trust, London, UK
- National Hospital for Neurology and Neurosurgery, Queen
Square, London, UK
| | - Ann-Maree Vallence
- Discipline of Psychology, College of Science, Health,
Engineering and Education, Murdoch University, Western Australia, Australia
| | - Simon Koblar
- Department of Medicine, The University of Adelaide,
Adelaide, Australia
- Department of Neurology, Royal Adelaide Hospital,
Adelaide, Australia
| | - Timothy Kleinig
- Department of Medicine, The University of Adelaide,
Adelaide, Australia
- Department of Neurology, Royal Adelaide Hospital,
Adelaide, Australia
| | | | - Richard Greenwood
- National Hospital for Neurology and Neurosurgery, Queen
Square, London, UK
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16
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Gamma frequency activation of inhibitory neurons in the acute phase after stroke attenuates vascular and behavioral dysfunction. Cell Rep 2021; 34:108696. [PMID: 33535035 DOI: 10.1016/j.celrep.2021.108696] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/06/2020] [Accepted: 01/06/2021] [Indexed: 11/24/2022] Open
Abstract
Alterations in gamma oscillations occur in several neurological disorders, and the entrainment of gamma oscillations has been recently proposed as a treatment for neurodegenerative disease. Optogenetic stimulation enhances recovery in models of stroke when applied weeks after injury; however, the benefits of acute brain stimulation have not been investigated. Here, we report beneficial effects of gamma-frequency modulation in the acute phase, within 1 h, after stroke. Transgenic VGAT-ChR2 mice are subject to awake photothrombotic stroke in an area encompassing the forelimb sensory and motor cortex. Optogenetic stimulation at 40 Hz in the peri-infarct zone recovers neuronal activity 24 h after stroke in motor and parietal association areas, as well as blood flow over the first week after stroke. Stimulation significantly reduces lesion volume and improves motor function. Our results suggest that acute-phase modulation of cortical oscillatory dynamics may serve as a target for neuroprotection against stroke.
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17
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Zoghi M, Hafezi P, Amatya B, Khan F, Galea MP. Intracortical Circuits in the Contralesional Primary Motor Cortex in Patients With Chronic Stroke After Botulinum Toxin Type A Injection: Case Studies. Front Hum Neurosci 2020; 14:342. [PMID: 33100987 PMCID: PMC7497670 DOI: 10.3389/fnhum.2020.00342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/03/2020] [Indexed: 11/22/2022] Open
Abstract
Spasticity and motor recovery are both related to neural plasticity after stroke. A balance of activity in the primary motor cortex (M1) in both hemispheres is essential for functional recovery. In this study, we assessed the intracortical inhibitory and facilitatory circuits in the contralesional M1 area in four patients with severe upper limb spasticity after chronic stroke and treated with botulinum toxin-A (BoNT-A) injection and 12 weeks of upper limb rehabilitation. There was little to no change in the level of spasticity post-injection, and only one participant experienced a small improvement in arm function. All reported improvements in quality of life. However, the levels of intracortical inhibition and facilitation in the contralesional hemisphere were different at baseline for all four participants, and there was no clear pattern in the response to the intervention. Further investigation is needed to understand how BoNT-A injections affect inhibitory and facilitatory circuits in the contralesional hemisphere, the severity of spasticity, and functional improvement.
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Affiliation(s)
- Maryam Zoghi
- Department of Physiotherapy, Podiatry, Prosthetics and Orthotics, La Trobe University, Melbourne, VIC, Australia
| | | | - Bhasker Amatya
- The Royal Melbourne Hospital, Melbourne, VIC, Australia.,University of Melbourne, Melbourne, VIC, Australia
| | - Fary Khan
- The Royal Melbourne Hospital, Melbourne, VIC, Australia.,University of Melbourne, Melbourne, VIC, Australia
| | - Mary Pauline Galea
- The Royal Melbourne Hospital, Melbourne, VIC, Australia.,University of Melbourne, Melbourne, VIC, Australia
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18
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Gaubatz J, Prillwitz CC, Ernst L, David B, Hoppe C, Hattingen E, Weber B, Vatter H, Surges R, Elger CE, Rüber T. Contralesional White Matter Alterations in Patients After Hemispherotomy. Front Hum Neurosci 2020; 14:262. [PMID: 32733222 PMCID: PMC7358777 DOI: 10.3389/fnhum.2020.00262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 06/12/2020] [Indexed: 12/17/2022] Open
Abstract
Cerebral lesions may cause degeneration and neuroplastic reorganization in both the ipsi- and the contralesional hemisphere, presumably creating an imbalance of primarily inhibitory interhemispheric influences produced via transcallosal pathways. The two hemispheres are thought to mutually hamper neuroplastic reorganization of the other hemisphere. The results of preceding degeneration and neuroplastic reorganization of white matter may be reflected by Diffusion Tensor Imaging-derived diffusivity parameters such as fractional anisotropy (FA). In this study, we applied Diffusion Tensor Imaging (DTI) to contrast the white matter status of the contralesional hemisphere of young lesioned brains with and without contralateral influences by comparing patients after hemispherotomy to those who had not undergone neurosurgery. DTI was applied to 43 healthy controls (26 females, mean age ± SD: 25.07 ± 11.33 years) and two groups of in total 51 epilepsy patients with comparable juvenile brain lesions (32 females, mean age ± SD: 25.69 ± 12.77 years) either after hemispherotomy (30 of 51 patients) or without neurosurgery (21 of 51 patients), respectively. FA values were compared between these groups using the unbiased tract-based spatial statistics approach. A voxel-wise ANCOVA controlling for age at scan yielded significant group differences in FA. A post hoc t-test between hemispherotomy patients and healthy controls revealed widespread supra-threshold voxels in the contralesional hemisphere of hemispherotomy patients indicating comparatively higher FA values (p < 0.05, FWE-corrected). The non-surgery group, in contrast, showed extensive supra-threshold voxels indicating lower FA values in the contralesional hemisphere as compared to healthy controls (p < 0.05, FWE-corrected). Whereas lower FA values are suggestive of pronounced contralesional degeneration in the non-surgery group, higher FA values in the hemispherotomy group may be interpreted as a result of preceding plastic remodeling. We conclude that, whether juvenile brain lesions are associated with contralesional degeneration or reorganization partly depends on the ipsilesional hemisphere. Contralesional reorganization as observed in hemispherotomy patients was most likely enabled by the complete neurosurgical deafferentation of the ipsilesional hemisphere and, thereby, the disinhibition of the neuroplastic potential of the contralesional hemisphere. The main argument of this study is that hemispherotomy may be seen as a major plastic stimulus and as a prerequisite for contralesional neuroplastic remodeling in patients with juvenile brain lesions.
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Affiliation(s)
- Jennifer Gaubatz
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Conrad C Prillwitz
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Leon Ernst
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Bastian David
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Christian Hoppe
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Elke Hattingen
- Department of Neuroradiology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Bernd Weber
- Institute for Experimental Epileptology and Cognition Research, University of Bonn Medical Center, Bonn, Germany
| | - Hartmut Vatter
- Department of Neurosurgery, University of Bonn Medical Center, Bonn, Germany
| | - Rainer Surges
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Christian E Elger
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Theodor Rüber
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University Frankfurt, Frankfurt am Main, Germany.,Center for Personalized Translational Epilepsy Research (CePTER), Goethe University Frankfurt, Frankfurt am Main, Germany
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19
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Cirillo J, Mooney RA, Ackerley SJ, Barber PA, Borges VM, Clarkson AN, Mangold C, Ren A, Smith MC, Stinear CM, Byblow WD. Neurochemical balance and inhibition at the subacute stage after stroke. J Neurophysiol 2020; 123:1775-1790. [PMID: 32186435 DOI: 10.1152/jn.00561.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Stroke is a leading cause of death and disability worldwide with many people left with impaired motor function. Evidence from experimental animal models of stroke indicates that reducing motor cortex inhibition may facilitate neural plasticity and motor recovery. This study compared primary motor cortex (M1) inhibition measures over the first 12 wk after stroke with a cohort of age-similar healthy controls. The excitation-inhibition ratio and gamma-aminobutyric acid (GABA) neurotransmission within M1 were assessed using magnetic resonance spectroscopy and threshold hunting paired-pulse transcranial magnetic stimulation respectively. Upper limb impairment and function were assessed with the Fugl-Meyer Upper Extremity Scale and Action Research Arm Test. Patients with a functional corticospinal pathway had motor-evoked potentials on the paretic side and exhibited better recovery from upper limb impairment and recovery of function than patients without a functional corticospinal pathway. Compared with age-similar controls, the neurochemical balance in terms of the excitation-inhibition ratio was greater within contralesional M1 in patients with a functional corticospinal pathway. There was evidence for elevated long-interval inhibition in both ipsilesional and contralesional M1 compared with controls. Short-interval inhibition measures differed between the first and second phases, with evidence for elevation of the former only in ipsilesional M1 and no evidence of disinhibition for the latter. Overall, findings from transcranial magnetic stimulation indicate an upregulation of GABA-mediated tonic inhibition in M1 early after stroke. Therapeutic approaches that aim to normalize inhibitory tone during the subacute period warrant further investigation.NEW & NOTEWORTHY Magnetic resonance spectroscopy indicated higher excitation-inhibition ratios within motor cortex during subacute recovery than age-similar healthy controls. Measures obtained from adaptive threshold hunting paired-pulse transcranial magnetic stimulation indicated greater tonic inhibition in patients compared with controls. Therapeutic approaches that aim to normalize motor cortex inhibition during the subacute stage of recovery should be explored.
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Affiliation(s)
- John Cirillo
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Ronan A Mooney
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Suzanne J Ackerley
- Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Medicine, University of Auckland, Auckland, New Zealand
| | - P Alan Barber
- Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Victor M Borges
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | | | - Christine Mangold
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - April Ren
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand
| | - Marie-Claire Smith
- Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Cathy M Stinear
- Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Winston D Byblow
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, Auckland, New Zealand
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20
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Wang H, Xu G, Wang X, Sun C, Zhu B, Fan M, Jia J, Guo X, Sun L. The Reorganization of Resting-State Brain Networks Associated With Motor Imagery Training in Chronic Stroke Patients. IEEE Trans Neural Syst Rehabil Eng 2019; 27:2237-2245. [DOI: 10.1109/tnsre.2019.2940980] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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21
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Selective serotonin reuptake inhibitors for functional recovery after stroke: similarities with the critical period and the role of experience-dependent plasticity. J Neurol 2019; 268:1203-1209. [PMID: 31346698 DOI: 10.1007/s00415-019-09480-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 01/01/2023]
Abstract
There has been a growing interest in the potential for plasticity-inducing pharmacological interventions to enhance post-stroke recovery. One group of drugs that continues to garner a great deal of attention in this regard is a class of antidepressants called the selective serotonin reuptake inhibitors. Here we propose a model for the mechanism by which these drugs may enhance plasticity after ischemic brain injury. First, we review the research in animal models demonstrating how selective serotonin reuptake inhibitors reopen the critical period for ocular dominance plasticity in adulthood. We then compare this period of heightened plasticity to the cellular and biochemical milieu of perilesional tissue after an ischemic event in the adult brain. We argue that selective serotonin reuptake inhibitors administered acutely after an ischemic stroke alter excitatory-inhibitory balance in perilesional tissue and reinstate a type of plasticity reminiscent of the critical period in development. Finally, we discuss opportunities for future research in this area in both the preclinical and clinical realms.
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22
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David B, Prillwitz CC, Hoppe C, Sassen R, Hörsch S, Weber B, Hattingen E, Elger CE, Rüber T. Morphometric MRI findings challenge the concept of the "unaffected" hemisphere in Rasmussen encephalitis. Epilepsia 2019; 60:e40-e46. [PMID: 30957874 DOI: 10.1111/epi.14702] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 01/15/2023]
Abstract
Rasmussen encephalitis (RE) is an immune-mediated brain disease with progressive unihemispheric atrophy. Although it is regarded as a strictly one-sided pathology, volumetric magnetic resonance imaging (MRI) studies have revealed atrophy in the so-called unaffected hemisphere. In contrast to previous studies, we hypothesized that the contralesional hemisphere would show increased gray matter volume in response to the ipsilesional atrophy. We assessed the gray matter volume differences among 21 patients with chronic, late-stage RE and 89 age- and gender-matched healthy controls using voxel-based morphometry. In addition, 11 patients with more than one scan were tested longitudinally. Compared to controls, the contralesional hemisphere of the patients revealed a higher cortical volume but a lower subcortical gray matter volume (all P < 0.001, unpaired t test). Progressive gray matter volume losses in bilateral subcortical gray matter structures were observed (P < 0.05, paired t test). The comparatively higher cortical volume in the contralesional hemisphere can be interpreted as a result of compensatory structural remodeling in response to atrophy of the ipsilesional hemisphere. Contralesional subcortical gray matter volume loss may be due to the pathology or its treatment. Because MRI provides the best marker for determining the progression of RE, an accurate description of its MRI features is clinically relevant.
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Affiliation(s)
- Bastian David
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Conrad C Prillwitz
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Christian Hoppe
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Robert Sassen
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Sophia Hörsch
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Bernd Weber
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Elke Hattingen
- Department of Radiology, University of Bonn Medical Center, Bonn, Germany.,Department of Neuroradiology, Goethe University Frankfurt, Frankfurt, Germany
| | - Christian E Elger
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
| | - Theodor Rüber
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
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23
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Vecchio F, Caliandro P, Reale G, Miraglia F, Piludu F, Masi G, Iacovelli C, Simbolotti C, Padua L, Leone E, Alù F, Colosimo C, Rossini PM. Acute cerebellar stroke and middle cerebral artery stroke exert distinctive modifications on functional cortical connectivity: A comparative study via EEG graph theory. Clin Neurophysiol 2019; 130:997-1007. [PMID: 31005052 DOI: 10.1016/j.clinph.2019.03.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 02/18/2019] [Accepted: 03/13/2019] [Indexed: 01/06/2023]
Abstract
OBJECTIVE We tested whether acute cerebellar stroke may determine changes in brain network architecture as defined by cortical sources of EEG rhythms. METHODS Graph parameters of 41 consecutive stroke patients (<5 days from the event) were studied using eLORETA EEG sources. Network rearrangements of stroke patients were investigated in delta, alpha 2, beta 2 and gamma bands in comparison with healthy subjects. RESULTS The delta network remodeling was similar in cerebellar and middle cerebral artery strokes, with a reduction of small-worldness. Beta 2 and gamma small-worldness, in the right hemisphere of patients with cerebellar stroke, increase respect to healthy subjects, while alpha 2 small-worldness increases only among patients with a middle cerebral artery stroke. CONCLUSIONS The network remodeling characteristics are independent on the size of the ischemic lesion. In the early post-acute stages cerebellar stroke differs from the middle cerebral artery one because it does not cause alpha 2 network remodeling while it determines a high frequency network reorganization in beta 2 and gamma bands with an increase of small-worldness characteristics. SIGNIFICANCE These findings demonstrate changes in the balance of local segregation and global integration induced by cerebellar acute stroke in high EEG frequency bands. They need to be integrated with appropriate follow-up to explore whether further network changes are attained during post-stroke outcome stabilization.
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Affiliation(s)
- Fabrizio Vecchio
- Brain Connectivity Laboratory, IRCCS San Raffaele Pisana, Rome, Italy
| | - Pietro Caliandro
- Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Giuseppe Reale
- Institute of Neurology, Area of Neuroscience, Catholic University of The Sacred Heart, Rome, Italy
| | | | - Francesca Piludu
- Department of radiologic sciences, Catholic University, Fondazione Policlincio Universitario A. Gemelli, Rome, Italy
| | - Gianvito Masi
- Institute of Neurology, Area of Neuroscience, Catholic University of The Sacred Heart, Rome, Italy
| | | | - Chiara Simbolotti
- Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Luca Padua
- Unità operativa di neuroriabilitazione ad alta intensità, Fondazione Policlinico Universitario A. Gemelli. IRCCS, Roma
| | - Edoardo Leone
- Department of radiologic sciences, Catholic University, Fondazione Policlincio Universitario A. Gemelli, Rome, Italy
| | - Francesca Alù
- Brain Connectivity Laboratory, IRCCS San Raffaele Pisana, Rome, Italy
| | - Cesare Colosimo
- Department of radiologic sciences, Catholic University, Fondazione Policlincio Universitario A. Gemelli, Rome, Italy
| | - Paolo Maria Rossini
- Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Institute of Neurology, Area of Neuroscience, Catholic University of The Sacred Heart, Rome, Italy
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24
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Ding Q, Triggs WJ, Kamath SM, Patten C. Short Intracortical Inhibition During Voluntary Movement Reveals Persistent Impairment Post-stroke. Front Neurol 2019; 9:1105. [PMID: 30662425 PMCID: PMC6328452 DOI: 10.3389/fneur.2018.01105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/03/2018] [Indexed: 01/09/2023] Open
Abstract
Objective: Short intracortical inhibition (SICI) is a GABAA-mediated phenomenon, argued to mediate selective muscle activation during coordinated motor activity. Markedly reduced SICI has been observed in the acute period following stroke and, based on findings in animal models, it has been posited this disinhibitory phenomenon may facilitate neural plasticity and contribute to early motor recovery. However, it remains unresolved whether SICI normalizes over time, as part of the natural course of stroke recovery. Whether intracortical inhibition contributes to motor recovery in chronic stroke also remains unclear. Notably, SICI is typically measured at rest, which may not fully reveal its role in motor control. Here we investigated SICI at rest and during voluntary motor activity to determine: (1) whether GABAA-mediated inhibition recovers, and (2) how GABAA-mediated inhibition is related to motor function, in the chronic phase post-stroke. Methods: We studied 16 chronic stroke survivors (age: 64.6 ± 9.3 years; chronicity: 74.3 ± 52.9 months) and 12 age-matched healthy controls. We used paired-pulse transcranial magnetic stimulation (TMS) to induce SICI during three conditions: rest, submaximal grip, and performance of box-and-blocks. Upper-extremity Fugl-Meyer Assessment and Box-and-Blocks tests were used to evaluate motor impairment in stroke survivors and manual dexterity in all participants, respectively. Results: At rest, SICI revealed no differences between ipsilesional and contralesional hemispheres of either cortical or subcortical stroke survivors, or healthy controls (P's > 0.05). During box-and-blocks, however, ipsilesional hemisphere SICI was significantly reduced (P = 0.025), especially following cortical stroke (P < 0.001). SICI in the ipsilesional hemisphere during box-and-blocks task was significantly related to paretic hand dexterity (r = 0.56, P = 0.039) and motor impairment (r = 0.56, P = 0.037). Conclusions: SICI during motor activity, but not rest, reveals persistent impairment in chronic stroke survivors indicating that inhibitory brain circuits responsible for motor coordination do not fully normalize as part of the natural history of stroke recovery. Observation that reduced SICI (i.e., disinhibition) is associated with greater motor impairment and worse dexterity in chronic hemiparetic individuals suggests the response considered to promote neuroplasticity and recovery in the acute phase could be maladaptive in the chronic phase post-stroke.
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Affiliation(s)
- Qian Ding
- Biomechanics, Rehabilitation, and Integrative Neuroscience Lab, Department of Physical Medicine and Rehabilitation, School of Medicine, University of California, Davis, Sacramento, CA, United States.,Rehabilitation Science PhD Program, University of Florida, Gainesville, FL, United States.,Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, United States
| | - William J Triggs
- Rehabilitation Science PhD Program, University of Florida, Gainesville, FL, United States.,Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, United States.,Department of Neurology, University of Florida, Gainesville, FL, United States
| | - Sahana M Kamath
- Rehabilitation Science PhD Program, University of Florida, Gainesville, FL, United States.,Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, United States
| | - Carolynn Patten
- Biomechanics, Rehabilitation, and Integrative Neuroscience Lab, Department of Physical Medicine and Rehabilitation, School of Medicine, University of California, Davis, Sacramento, CA, United States.,Rehabilitation Science PhD Program, University of Florida, Gainesville, FL, United States.,Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, United States
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25
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Hwang J, Shin Y, Park JH, Cha YJ, You JSH. Effects of Walkbot gait training on kinematics, kinetics, and clinical gait function in paraplegia and quadriplegia. NeuroRehabilitation 2018; 42:481-489. [PMID: 29660947 DOI: 10.3233/nre-172226] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The robotic-assisted gait training (RAGT) system has gained recognition as an innovative, effective paradigm to improve functional ambulation and activities of daily living in spinal cord injury and stroke. However, the effects of the Walkbot robotic-assisted gait training system with a specialized hip-knee-ankle actuator have never been examined in the paraplegia and quadriplegia population. OBJECTIVE The aim of this study was to determine the long-term effects of Walkbot training on clinical for hips and knee stiffness in individuals with paraplegia or quadriplegia. METHODS Nine adults with subacute or chronic paraplegia resulting from spinal cord injury or quadriplegia resulting from cerebral vascular accident (CVA) and/or hypoxia underwent progressive conventional gait retraining combined with the Walkbot RAGT for 5 days/week over an average of 43 sessions for 8 weeks. Clinical outcomes were measured with the Functional Ambulation Category (FAC), Modified Rankin Scale (MRS), Korean version of the Modified Barthel Index (K-MBI), Modified Ashworth Scale (MAS). Kinetic and kinematic data were collected via a built-in Walkbot program. RESULTS Wilcoxon signed-rank tests showed significant positive intervention effects on K-MBI, maximal hip flexion and extension, maximal knee flexion, active torque in the knee joint, resistive torque, and stiffness in the hip joint (P < 0.05). These findings suggest that the Walkbot RAGT was effective for improving knee and hip kinematics and the active knee joint moment while decreasing hip resistive force. These improvements were associated with functional recovery in gait, balance, mobility and daily activities. CONCLUSIONS These findings suggest that the Walkbot RAGT was effective for improving knee and hip kinematics and the active knee joint moment while decreasing hip resistive force. This is the first clinical evidence for intensive, long-term effects of the Walkbot RAGT on active or resistive moments and stiffness associated with spasticity and functional mobility in individuals with subacute or chronic paraplegia or quadriplegia who had reached a plateau in motor recovery after conventional therapy.
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Affiliation(s)
- Jongseok Hwang
- Department of Physical Therapy, Sports Movement Artificial Robotics Technology (SMART) Institute, Yonsei University, Wonju, Republic of Korea
| | - Yongil Shin
- Department of Rehabilitation Medicine, Pusan National University School of Medicine, Pusan, Republic of Korea
| | - Ji-Ho Park
- Department of Physical Therapy, Sports Movement Artificial Robotics Technology (SMART) Institute, Yonsei University, Wonju, Republic of Korea
| | - Young Joo Cha
- Department of Physical Therapy, Sports Movement Artificial Robotics Technology (SMART) Institute, Yonsei University, Wonju, Republic of Korea
| | - Joshua Sung H You
- Department of Physical Therapy, Sports Movement Artificial Robotics Technology (SMART) Institute, Yonsei University, Wonju, Republic of Korea
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26
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Abraha B, Chaves AR, Kelly LP, Wallack EM, Wadden KP, McCarthy J, Ploughman M. A Bout of High Intensity Interval Training Lengthened Nerve Conduction Latency to the Non-exercised Affected Limb in Chronic Stroke. Front Physiol 2018; 9:827. [PMID: 30013489 PMCID: PMC6036480 DOI: 10.3389/fphys.2018.00827] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/12/2018] [Indexed: 12/13/2022] Open
Abstract
Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke. Design: Randomized cross-over trial. Setting: Research laboratory in a tertiary rehabilitation hospital. Participants: Convenience sample of 12 chronic stroke survivors. Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength). Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R2 = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R2 = 0.26 p = 0.02). Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.
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Affiliation(s)
- Beraki Abraha
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Arthur R Chaves
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Liam P Kelly
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Elizabeth M Wallack
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Katie P Wadden
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Jason McCarthy
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Michelle Ploughman
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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27
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Buetefisch CM, Revill KP, Haut MW, Kowalski GM, Wischnewski M, Pifer M, Belagaje SR, Nahab F, Cobia DJ, Hu X, Drake D, Hobbs G. Abnormally reduced primary motor cortex output is related to impaired hand function in chronic stroke. J Neurophysiol 2018; 120:1680-1694. [PMID: 29924707 DOI: 10.1152/jn.00715.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Stroke often involves primary motor cortex (M1) and its corticospinal projections (CST). As hand function is critically dependent on these structures, its recovery is often incomplete. The neuronal substrate supporting affected hand function is not well understood but likely involves reorganized M1 and CST of the lesioned hemisphere (M1IL and CSTIL). We hypothesized that affected hand function in chronic stroke is related to structural and functional reorganization of M1IL and CSTIL. We tested 18 patients with chronic ischemic stroke involving M1 or CST. Their hand function was compared with 18 age-matched healthy subjects. M1IL thickness and CSTIL fractional anisotropy (FA) were determined with MRI and compared with measures of the other hemisphere. Transcranial magnetic stimulation (TMS) was applied to M1IL to determine its input-output function [stimulus response curve (SRC)]. The plateau of the SRC (MEPmax), inflection point, and slope parameters of the curve were extracted. Results were compared with measures in 12 age-matched healthy controls. MEPmax of M1IL was significantly smaller ( P = 0.02) in the patients, indicating reduced CSTIL motor output, and was correlated with impaired hand function ( P = 0.02). M1IL thickness ( P < 0.01) and CSTIL-FA ( P < 0.01) were reduced but did not correlate with hand function. The results indicate that employed M1IL or CSTIL structural measures do not explain the extent of impairment in hand function once M1 and CST are sufficiently functional for TMS to evoke a motor potential. Instead, impairment of hand function is best explained by the abnormally low output from M1IL. NEW & NOTEWORTHY Hand function often remains impaired after stroke. While the critical role of the primary motor cortex (M1) and its corticospinal output (CST) for hand function has been described in the nonhuman primate stroke model, their structure and function have not been systematically evaluated for patients after stroke. We report that in chronic stroke patients with injury to M1 and/or CST an abnormally reduced M1 output is related to impaired hand function.
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Affiliation(s)
- C M Buetefisch
- Department of Neurology, Emory University , Atlanta, Georgia.,Department of Rehabilitation Medicine, Emory University , Atlanta, Georgia
| | - K P Revill
- Department of Psychology, Emory University , Atlanta, Georgia
| | - M W Haut
- Department of Behavioral Medicine and Psychiatry, West Virginia University School of Medicine , Morgantown, West Virginia.,Department of Neurology, West Virginia University School of Medicine , Morgantown, West Virginia.,Department of Radiology, West Virginia University School of Medicine , Morgantown, West Virginia
| | - G M Kowalski
- Department of Neurology, Emory University , Atlanta, Georgia
| | - M Wischnewski
- Department of Neurology, Emory University , Atlanta, Georgia
| | - M Pifer
- Department of Behavioral Medicine and Psychiatry, West Virginia University School of Medicine , Morgantown, West Virginia
| | - S R Belagaje
- Department of Neurology, Emory University , Atlanta, Georgia.,Marcus Stroke and Neuroscience Center, Grady Memorial Hospital , Atlanta, Georgia
| | - F Nahab
- Department of Neurology, Emory University , Atlanta, Georgia
| | - D J Cobia
- Department of Psychology and Neuroscience Center, Brigham Young University , Provo, Utah
| | - X Hu
- Department of Bioengineering, University of California Riverside , Riverside, California
| | - D Drake
- Department of Biostatistics, The Mailman School of Public Health, Columbia University , New York, New York
| | - G Hobbs
- Department of Statistics, West Virginia University , Morgantown, West Virginia
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28
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Recovery of the 20 Hz Rebound to Tactile and Proprioceptive Stimulation after Stroke. Neural Plast 2018; 2018:7395798. [PMID: 29681928 PMCID: PMC5851173 DOI: 10.1155/2018/7395798] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/12/2017] [Indexed: 01/16/2023] Open
Abstract
Sensorimotor integration is closely linked to changes in motor-cortical excitability, observable in the modulation of the 20 Hz rhythm. After somatosensory stimulation, the rhythm transiently increases as a rebound that reflects motor-cortex inhibition. Stroke-induced alterations in afferent input likely affect motor-cortex excitability and motor recovery. To study the role of somatosensory afferents in motor-cortex excitability after stroke, we employed magnetoencephalographic recordings (MEG) at 1–7 days, one month, and 12 months in 23 patients with stroke in the middle cerebral artery territory and 22 healthy controls. The modulation of the 20 Hz motor-cortical rhythm was evaluated to two different somatosensory stimuli, tactile stimulation, and passive movement of the index fingers. The rebound strengths to both stimuli were diminished in the acute phase compared to the controls and increased significantly during the first month after stroke. However, only the rebound amplitudes to tactile stimuli fully recovered within the follow-up period. The rebound strengths in the affected hemisphere to both stimuli correlated strongly with the clinical scores across the follow-up. The results show that changes in the 20 Hz rebound to both stimuli behave similarly and occur predominantly during the first month. The 20 Hz rebound is a potential marker for predicting motor recovery after stroke.
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29
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Li S, Bhadane M, Gao F, Zhou P. The Reticulospinal Pathway Does Not Increase Its Contribution to the Strength of Contralesional Muscles in Stroke Survivors as Compared to Ipsilesional Side or Healthy Controls. Front Neurol 2017; 8:627. [PMID: 29230191 PMCID: PMC5712067 DOI: 10.3389/fneur.2017.00627] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/09/2017] [Indexed: 11/13/2022] Open
Abstract
Objective Startling acoustic stimulation (SAS), via activation of reticulospinal (RS) pathways, has shown to increase muscle strength in healthy subjects. We hypothesized that, given RS hyperexcitability in stroke survivors, SAS could increase muscle strength in stroke survivors. The objective was to quantify the effect of SAS on maximal and sub-maximal voluntary elbow flexion on the contralesional (impaired) side in stroke survivors as compared to ipsilesional (non-impaired) side and healthy controls. Design Thirteen hemiparetic stroke survivors and 12 healthy subjects volunteered for this investigation. Acoustic stimulation was given at rest, during ballistic maximal and sustained sub-maximal isometric elbow contractions using low (80 dB) and high intensity sound (105 dB). The effect of acoustic stimuli was evaluated from EMG and force recordings. Results Prevalence of acoustic startle reflex with shorter latency in the impaired biceps was greater as compared to the response in the non-impaired side of stroke subjects and in healthy subjects. Delivery of SAS resulted in earlier initiation of elbow flexion and greater peak torque in healthy subjects and in stroke subjects with spastic hemiplegia during maximal voluntary elbow flexion tasks. During sub-maximal elbow flexion tasks, SAS-induced force responses were slightly greater on the impaired side than the non-impaired side. However, no statistically significant difference was found in SAS-induced responses between impaired and non-impaired sides at maximal and sub-maximal elbow flexion tasks. Conclusion The findings suggest RS hyperexcitability in stroke survivors with spastic hemiplegia. The results of similar SAS-induced responses between healthy and stroke subjects indicate that RS projections via acoustic stimulation are not likely to contribute to muscle strength for stroke survivors to a significant extent.
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Affiliation(s)
- Sheng Li
- Department of Physical Medicine and Rehabilitation, McGoven Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Minal Bhadane
- Department of Physical Medicine and Rehabilitation, McGoven Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, United States
| | - Fan Gao
- The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, McGoven Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, United States
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Petrovic J, Milosevic V, Zivkovic M, Stojanov D, Milojkovic O, Kalauzi A, Saponjic J. Slower EEG alpha generation, synchronization and "flow"-possible biomarkers of cognitive impairment and neuropathology of minor stroke. PeerJ 2017; 5:e3839. [PMID: 28970969 PMCID: PMC5623310 DOI: 10.7717/peerj.3839] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/01/2017] [Indexed: 11/20/2022] Open
Abstract
Background We investigated EEG rhythms, particularly alpha activity, and their relationship to post-stroke neuropathology and cognitive functions in the subacute and chronic stages of minor strokes. Methods We included 10 patients with right middle cerebral artery (MCA) ischemic strokes and 11 healthy controls. All the assessments of stroke patients were done both in the subacute and chronic stages. Neurological impairment was measured using the National Institute of Health Stroke Scale (NIHSS), whereas cognitive functions were assessed using the Montreal Cognitive Assessment (MoCA) and MoCA memory index (MoCA-MIS). The EEG was recorded using a 19 channel EEG system with standard EEG electrode placement. In particular, we analyzed the EEGs derived from the four lateral frontal (F3, F7, F4, F8), and corresponding lateral posterior (P3, P4, T5, T6) electrodes. Quantitative EEG analysis included: the group FFT spectra, the weighted average of alpha frequency (αAVG), the group probability density distributions of all conventional EEG frequency band relative amplitudes (EEG microstructure), the inter- and intra-hemispheric coherences, and the topographic distribution of alpha carrier frequency phase potentials (PPs). Statistical analysis was done using a Kruskal–Wallis ANOVA with a post-hoc Mann–Whitney U two-tailed test, and Spearman’s correlation. Results We demonstrated transient cognitive impairment alongside a slower alpha frequency (αAVG) in the subacute right MCA stroke patients vs. the controls. This slower alpha frequency showed no amplitude change, but was highly synchronized intra-hemispherically, overlying the ipsi-lesional hemisphere, and inter-hemispherically, overlying the frontal cortex. In addition, the disturbances in EEG alpha activity in subacute stroke patients were expressed as a decrease in alpha PPs over the frontal cortex and an altered “alpha flow”, indicating the sustained augmentation of inter-hemispheric interactions. Although the stroke induced slower alpha was a transient phenomenon, the increased alpha intra-hemispheric synchronization, overlying the ipsi-lesional hemisphere, the increased alpha F3–F4 inter-hemispheric synchronization, the delayed alpha waves, and the newly established inter-hemispheric “alpha flow” within the frontal cortex, remained as a permanent consequence of the minor stroke. This newly established frontal inter-hemispheric “alpha flow” represented a permanent consequence of the “hidden” stroke neuropathology, despite the fact that cognitive impairment has been returned to the control values. All the detected permanent changes at the EEG level with no cognitive impairment after a minor stroke could be a way for the brain to compensate for the lesion and restore the lost function. Discussion Our study indicates slower EEG alpha generation, synchronization and “flow” as potential biomarkers of cognitive impairment onset and/or compensatory post-stroke re-organizational processes.
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Affiliation(s)
- Jelena Petrovic
- Department of Neurobiology, Institute for Biological Research-Sinisa Stankovic, University of Belgrade, Belgrade, Serbia
| | - Vuk Milosevic
- Clinic of Neurology, Clinical Center Nis, Nis, Serbia
| | | | | | - Olga Milojkovic
- Clinic for Mental Health Protection, Clinical Center Nis, Nis, Serbia
| | - Aleksandar Kalauzi
- Department for Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Belgrade, Serbia
| | - Jasna Saponjic
- Department of Neurobiology, Institute for Biological Research-Sinisa Stankovic, University of Belgrade, Belgrade, Serbia
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McDonnell MN, Stinear CM. TMS measures of motor cortex function after stroke: A meta-analysis. Brain Stimul 2017; 10:721-734. [DOI: 10.1016/j.brs.2017.03.008] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/27/2017] [Accepted: 03/20/2017] [Indexed: 01/05/2023] Open
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32
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Savidan J, Kaeser M, Belhaj-Saïf A, Schmidlin E, Rouiller EM. Role of primary motor cortex in the control of manual dexterity assessed via sequential bilateral lesion in the adult macaque monkey: A case study. Neuroscience 2017. [PMID: 28629845 DOI: 10.1016/j.neuroscience.2017.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
From a case study, we describe the impact of unilateral lesion of the hand area in the primary motor cortex (M1) on manual dexterity and the role of the intact contralesional M1 in long-term functional recovery. An adult macaque monkey performed two manual dexterity tasks: (i) "modified Brinkman board" task, assessed simple precision grip versus complex precision grip, the latter involved a hand postural adjustment; (ii) "modified Klüver board" task, assessed movements ranging from power grip to precision grip, pre-shaping and grasping. Two consecutive unilateral M1 lesions targeted the hand area of each hemisphere, the second lesion was performed after stable, though incomplete, functional recovery from the primary lesion. Following each lesion, the manual dexterity of the contralesional hand was affected in a comparable manner, effects being progressively more deleterious from power grip to simple and then complex precision grips. Both tasks yielded consistent data, namely that the secondary M1 lesion did not have a significant impact on the recovered performance from the primary M1 lesion, which took place 5months earlier. In conclusion, the intact contralesional M1 did not play a major role in the long-term functional recovery from a primary M1 lesion targeted to the hand area.
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Affiliation(s)
- Julie Savidan
- Department of Medicine, Fribourg Centre for Cognition, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
| | - Mélanie Kaeser
- Department of Medicine, Fribourg Centre for Cognition, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
| | - Abderraouf Belhaj-Saïf
- Department of Medicine, Fribourg Centre for Cognition, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
| | - Eric Schmidlin
- Department of Medicine, Fribourg Centre for Cognition, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
| | - Eric M Rouiller
- Department of Medicine, Fribourg Centre for Cognition, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.
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33
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Palmer JA, Hsiao H, Wright T, Binder-Macleod SA. Single Session of Functional Electrical Stimulation-Assisted Walking Produces Corticomotor Symmetry Changes Related to Changes in Poststroke Walking Mechanics. Phys Ther 2017; 97:550-560. [PMID: 28339828 PMCID: PMC5803760 DOI: 10.1093/ptj/pzx008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 01/11/2017] [Indexed: 11/12/2022]
Abstract
BACKGROUND Recent research demonstrated that the symmetry of corticomotor drive with the paretic and nonparetic plantarflexor muscles was related to the biomechanical ankle moment strategy that people with chronic stroke used to achieve their greatest walking speeds. Rehabilitation strategies that promote corticomotor balance might improve poststroke walking mechanics and enhance functional ambulation. OBJECTIVE The study objectives were to test the effectiveness of a single session of gait training using functional electrical stimulation (FES) to improve plantarflexor corticomotor symmetry and plantarflexion ankle moment symmetry and to determine whether changes in corticomotor symmetry were related to changes in ankle moment symmetry within the session. DESIGN This was a repeated-measures crossover study. METHODS On separate days, 20 people with chronic stroke completed a session of treadmill walking either with or without the use of FES of their ankle dorsi- and plantarflexor muscles. We calculated plantarflexor corticomotor symmetry using transcranial magnetic stimulation and plantarflexion ankle moment symmetry during walking between the paretic and the nonparetic limbs before and after each session. We compared changes and tested relationships between corticomotor symmetry and ankle moment symmetry following each session. RESULTS Following the session with FES, there was an increase in plantarflexor corticomotor symmetry that was related to the observed increase in ankle moment symmetry. In contrast, following the session without FES, there were no changes in corticomotor symmetry or ankle moment symmetry. LIMITATIONS No stratification was made on the basis of lesion size, location, or clinical severity. CONCLUSIONS These findings demonstrate, for the first time (to our knowledge), the ability of a single session of gait training with FES to induce positive corticomotor plasticity in people in the chronic stage of stroke recovery. They also provide insight into the neurophysiologic mechanisms underlying improvements in biomechanical walking function.
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Affiliation(s)
- Jacqueline A. Palmer
- J.A. Palmer, PT, DPT, PhD, Department of Rehabilitation Medicine, Emory University, 1441 Clifton Rd NE, RG36A, Atlanta, GA 30322 (USA)
| | - HaoYuan Hsiao
- H.Y. Hsiao, PhD, Department of Physical Therapy and Rehabilitation Science, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Tamara Wright
- T. Wright, PT, DPT, Department of Physical Therapy, University of Delaware, Delaware
| | - Stuart A. Binder-Macleod
- S.A. Binder-Macleod, PT, PhD, Department of Physical Therapy, University of Delaware, and Graduate Program in Biomechanics and Movement Science, University of Delaware, Delaware
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Abstract
Stroke instigates a dynamic process of repair and remodelling of remaining neural circuits, and this process is shaped by behavioural experiences. The onset of motor disability simultaneously creates a powerful incentive to develop new, compensatory ways of performing daily activities. Compensatory movement strategies that are developed in response to motor impairments can be a dominant force in shaping post-stroke neural remodelling responses and can have mixed effects on functional outcome. The possibility of selectively harnessing the effects of compensatory behaviour on neural reorganization is still an insufficiently explored route for optimizing functional outcome after stroke.
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Affiliation(s)
- Theresa A Jones
- Department of Psychology and Institute for Neuroscience, University of Texas at Austin, Texas 78712, USA
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35
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Carey JR, Chappuis DM, Finkelstein MJ, Frost KL, Leuty LK, McNulty AL, Oddsson LIE, Seifert EM, Kimberley TJ. Importance and Difficulties of Pursuing rTMS Research in Acute Stroke. Phys Ther 2017; 97:310-319. [PMID: 28426872 PMCID: PMC5803765 DOI: 10.1093/ptj/pzx005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 12/11/2016] [Indexed: 12/19/2022]
Abstract
Although much research has been done on repetitive transcranial magnetic stimulation (rTMS) in chronic stroke, only sparse research has been done in acute stroke despite the particularly rich potential for neuroplasticity in this stage. We attempted a preliminary clinical trial in one active, high-quality inpatient rehabilitation facility (IRF) in the -United States. But after enrolling only 4 patients in the grant period, the study was stopped because of low enrollment. The purpose of this paper is to offer a perspective describing the important physiologic rationale for including rTMS in the early phase of stroke, the reasons for our poor patient enrollment in our attempted study, and recommendations to help future studies succeed. We conclude that, if scientists and clinicians hope to enhance stroke outcomes, more attention must be directed to leveraging conventional rehabilitation with neuromodulation in the acute phase of stroke when the capacity for neuroplasticity is optimal. Difficulties with patient enrollment must be addressed by reassessing traditional inclusion and exclusion criteria. Factors that shorten patients' length of stay in the IRF must also be reassessed at all policy-making levels to make ethical decisions that promote higher functional outcomes while retaining cost consciousness.
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Affiliation(s)
- James R. Carey
- J. R. Carey, PT, PhD, Division of Physical Therapy and Division of Rehabilitation Science, University of Minnesota, 420 Delaware St SE, Minneapolis, MN 55455 (USA). Address all correspondence to Dr Carey at:
| | - Diane M. Chappuis
- D. M. Chappuis, MD, Physical Medicine and Rehabilitation, Courage Kenny Rehabilitation Institute, Minneapolis, Minnesota
| | | | - Kate L. Frost
- K. L. Frost, Graduate Program in Rehabilitation Science, University of Minnesota
| | - Lynette K. Leuty
- L. K. Leuty, PT, DPT, Physical Medicine and Rehabilitation, Courage Kenny Rehabilitation Institute
| | - Allison L. McNulty
- A. L. McNulty, PT, DPT, Physical Medicine and Rehabilitation, Courage Kenny Rehabilitation Institute
| | - Lars I. E. Oddsson
- L.I.E. Oddsson, PhD, Division of -Rehabilitation Science, University of -Minnesota
| | - Erin M. Seifert
- E. M. Seifert, PT, DPT, Physical Medicine and Rehabilitation, Courage Kenny Rehabilitation Institute
| | - Teresa J. Kimberley
- T. J. Kimberley, PT, PhD, Division of Physical Therapy and Division of Rehabilitation Science, University of Minnesota
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Palmer JA, Zarzycki R, Morton SM, Kesar TM, Binder-Macleod SA. Characterizing differential poststroke corticomotor drive to the dorsi- and plantarflexor muscles during resting and volitional muscle activation. J Neurophysiol 2017; 117:1615-1624. [PMID: 28077661 DOI: 10.1152/jn.00393.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 12/16/2016] [Accepted: 01/08/2017] [Indexed: 12/20/2022] Open
Abstract
Imbalance of corticomotor excitability between the paretic and nonparetic limbs has been associated with the extent of upper extremity motor recovery poststroke, is greatly influenced by specific testing conditions such as the presence or absence of volitional muscle activation, and may vary across muscle groups. However, despite its clinical importance, poststroke corticomotor drive to lower extremity muscles has not been thoroughly investigated. Additionally, whereas conventional gait rehabilitation strategies for stroke survivors focus on paretic limb foot drop and dorsiflexion impairments, most contemporary literature has indicated that paretic limb propulsion and plantarflexion impairments are the most significant limiters to poststroke walking function. The purpose of this study was to compare corticomotor excitability of the dorsi- and plantarflexor muscles during resting and active conditions in individuals with good and poor poststroke walking recovery and in neurologically intact controls. We found that plantarflexor muscles showed reduced corticomotor symmetry between paretic and nonparetic limbs compared with dorsiflexor muscles in individuals with poor poststroke walking recovery during active muscle contraction but not during rest. Reduced plantarflexor corticomotor symmetry during active muscle contraction was a result of reduced corticomotor drive to the paretic muscles and enhanced corticomotor drive to the nonparetic muscles compared with the neurologically intact controls. These results demonstrate that atypical corticomotor drive exists in both the paretic and nonparetic lower limbs and implicate greater severity of corticomotor impairments to plantarflexor vs. dorsiflexor muscles during muscle activation in stroke survivors with poor walking recovery.NEW & NOTEWORTHY The present study observed that lower-limb corticomotor asymmetry resulted from both reduced paretic and enhanced nonparetic limb corticomotor excitability compared with neurologically intact controls. The most asymmetrical corticomotor drive was observed in the plantarflexor muscles of individuals with poor poststroke walking recovery. This suggests that neural function of dorsi- and plantarflexor muscles in both paretic and nonparetic limbs may play a role in poststroke walking function, which may have important implications when developing targeted poststroke rehabilitation programs to improve walking ability.
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Affiliation(s)
- Jacqueline A Palmer
- Division of Physical Therapy, School of Medicine, Emory University, Atlanta, Georgia
| | - Ryan Zarzycki
- Department of Physical Therapy, University of Delaware, Newark, Delaware.,Graduate Program in Biomechanics and Movement Science, University of Delaware, Newark, Delaware; and
| | - Susanne M Morton
- Department of Physical Therapy, University of Delaware, Newark, Delaware.,Graduate Program in Biomechanics and Movement Science, University of Delaware, Newark, Delaware; and
| | - Trisha M Kesar
- Division of Physical Therapy, School of Medicine, Emory University, Atlanta, Georgia
| | - Stuart A Binder-Macleod
- Department of Physical Therapy, University of Delaware, Newark, Delaware.,Graduate Program in Biomechanics and Movement Science, University of Delaware, Newark, Delaware; and
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Halme HL, Parkkonen L. Comparing Features for Classification of MEG Responses to Motor Imagery. PLoS One 2016; 11:e0168766. [PMID: 27992574 PMCID: PMC5161474 DOI: 10.1371/journal.pone.0168766] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 12/05/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Motor imagery (MI) with real-time neurofeedback could be a viable approach, e.g., in rehabilitation of cerebral stroke. Magnetoencephalography (MEG) noninvasively measures electric brain activity at high temporal resolution and is well-suited for recording oscillatory brain signals. MI is known to modulate 10- and 20-Hz oscillations in the somatomotor system. In order to provide accurate feedback to the subject, the most relevant MI-related features should be extracted from MEG data. In this study, we evaluated several MEG signal features for discriminating between left- and right-hand MI and between MI and rest. METHODS MEG was measured from nine healthy participants imagining either left- or right-hand finger tapping according to visual cues. Data preprocessing, feature extraction and classification were performed offline. The evaluated MI-related features were power spectral density (PSD), Morlet wavelets, short-time Fourier transform (STFT), common spatial patterns (CSP), filter-bank common spatial patterns (FBCSP), spatio-spectral decomposition (SSD), and combined SSD+CSP, CSP+PSD, CSP+Morlet, and CSP+STFT. We also compared four classifiers applied to single trials using 5-fold cross-validation for evaluating the classification accuracy and its possible dependence on the classification algorithm. In addition, we estimated the inter-session left-vs-right accuracy for each subject. RESULTS The SSD+CSP combination yielded the best accuracy in both left-vs-right (mean 73.7%) and MI-vs-rest (mean 81.3%) classification. CSP+Morlet yielded the best mean accuracy in inter-session left-vs-right classification (mean 69.1%). There were large inter-subject differences in classification accuracy, and the level of the 20-Hz suppression correlated significantly with the subjective MI-vs-rest accuracy. Selection of the classification algorithm had only a minor effect on the results. CONCLUSIONS We obtained good accuracy in sensor-level decoding of MI from single-trial MEG data. Feature extraction methods utilizing both the spatial and spectral profile of MI-related signals provided the best classification results, suggesting good performance of these methods in an online MEG neurofeedback system.
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Affiliation(s)
- Hanna-Leena Halme
- Department of Neuroscience and Biomedical Engineering (NBE), Aalto University School of Science, Espoo, Finland
- Radiology Unit, HUS Medical Imaging Center, Helsinki University Hospital, Helsinki, Finland
| | - Lauri Parkkonen
- Department of Neuroscience and Biomedical Engineering (NBE), Aalto University School of Science, Espoo, Finland
- Aalto Neuroimaging, MEG Core, Aalto University School of Science, Espoo, Finland
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38
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Cortical reorganization of the healthy hand in upper-limb complex regional pain syndrome(CRPS): Is reorganizations of common beliefs about CRPS necessary? Scand J Pain 2016; 13:136-137. [DOI: 10.1016/j.sjpain.2016.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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39
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Schambra HM, Martinez-Hernandez IE, Slane KJ, Boehme AK, Marshall RS, Lazar RM. The neurophysiological effects of single-dose theophylline in patients with chronic stroke: A double-blind, placebo-controlled, randomized cross-over study. Restor Neurol Neurosci 2016; 34:799-813. [PMID: 27567756 PMCID: PMC5333922 DOI: 10.3233/rnn-160657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Reducing inhibitory neurotransmission with pharmacological agents is a potential approach for augmenting plasticity after stroke. Previous work in healthy subjects showed diminished intracortical inhibition after administration of theophylline. OBJECTIVE We assessed the effect of single-dose theophylline on intracortical and interhemispheric inhibition in patients with chronic stroke, in a double-blind, placebo-controlled, cross-over study. METHODS Eighteen subjects were randomly administered 300 mg of extended-release theophylline or placebo. Immediately and 5 hours following administration, transcranial magnetic stimulation was used to assess bihemispheric resting motor threshold, short-interval intracortical inhibition, long-interval intracortical inhibition, and interhemispheric inhibition. Adverse effects on cardiovascular, neurological, and motor performance outcomes were also surveilled. Change between morning and afternoon sessions were compared across conditions. One week later, patients underwent the same assessments after crossing over to the opposite experimental condition. Subjects and investigators were blinded to the experimental condition during data acquisition and analysis. RESULTS For both hemispheres, changes in intracortical or interhemispheric neurophysiology were comparable under theophylline and placebo conditions. Theophylline induced no adverse neurological, cardiovascular, or motor performance effects. For both conditions and hemipsheres, the baseline level of inhibition inversely correlated with its change between sessions: less baseline inhibition (i.e. disinhibition) was associated with a strengthening in inhibition over the day, and vice versa. CONCLUSION A single dose of theophylline is well-tolerated by patients with chronic stroke, but does not alter cortical excitability. The inverse relationship between baseline inhibition and its change suggests the existence of a homeostatic process. The lack of effect on cortical inhibition may be related to an insufficiently long exposure to theophylline, or to differential responsiveness of disinhibited neural circuitry in patients with stroke.
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Affiliation(s)
- Heidi M. Schambra
- Departments of Neurology and Rehabilitation and Regenerative Medicine, Motor Performance Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Isis E. Martinez-Hernandez
- Departments of Neurology and Rehabilitation and Regenerative Medicine, Motor Performance Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Kevin J. Slane
- Department of Neurology, Richard and Jenny Levine Cerebral Localization Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Amelia K. Boehme
- Department of Neurology, Richard and Jenny Levine Cerebral Localization Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Randolph S. Marshall
- Department of Neurology, Richard and Jenny Levine Cerebral Localization Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Ronald M. Lazar
- Department of Neurology, Richard and Jenny Levine Cerebral Localization Laboratory, Columbia University Medical Center, New York, NY, USA
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40
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Wu P, Zhou YM, Zeng F, Li ZJ, Luo L, Li YX, Fan W, Qiu LH, Qin W, Chen L, Bai L, Nie J, Zhang S, Xiong Y, Bai Y, Yin CX, Liang FR. Regional brain structural abnormality in ischemic stroke patients: a voxel-based morphometry study. Neural Regen Res 2016; 11:1424-1430. [PMID: 27857744 PMCID: PMC5090843 DOI: 10.4103/1673-5374.191215] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2016] [Indexed: 02/05/2023] Open
Abstract
Our previous study used regional homogeneity analysis and found that activity in some brain areas of patients with ischemic stroke changed significantly. In the current study, we examined structural changes in these brain regions by taking structural magnetic resonance imaging scans of 11 ischemic stroke patients and 15 healthy participants, and analyzing the data using voxel-based morphometry. Compared with healthy participants, patients exhibited higher gray matter density in the left inferior occipital gyrus and right anterior white matter tract. In contrast, gray matter density in the right cerebellum, left precentral gyrus, right middle frontal gyrus, and left middle temporal gyrus was less in ischemic stroke patients. The changes of gray matter density in the middle frontal gyrus were negatively associated with the clinical rating scales of the Fugl-Meyer Motor Assessment (r = -0.609, P = 0.047) and the left middle temporal gyrus was negatively correlated with the clinical rating scales of the nervous functional deficiency scale (r = -0.737, P = 0.010). Our findings can objectively identify the functional abnormality in some brain regions of ischemic stroke patients.
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Affiliation(s)
- Ping Wu
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Yu-mei Zhou
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Fang Zeng
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Zheng-jie Li
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Lu Luo
- China Academy of Chinese Medical Sciences, World Federation of Acupuncture-Moxibustion Societies, Beijing, China
| | - Yong-xin Li
- Institute of Clinical Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Wei Fan
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Li-hua Qiu
- Radiology Department, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Wei Qin
- Life Sciences Research Center, School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi Province, China
| | - Lin Chen
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Lin Bai
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Juan Nie
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - San Zhang
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Yan Xiong
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Yu Bai
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Can-xin Yin
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
| | - Fan-rong Liang
- Acupuncture and Tuina School/Third Teaching Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China
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41
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Doruk D, Simis M, Imamura M, Brunoni AR, Morales-Quezada L, Anghinah R, Fregni F, Battistella LR. Neurophysiologic Correlates of Post-stroke Mood and Emotional Control. Front Hum Neurosci 2016; 10:428. [PMID: 27625600 PMCID: PMC5003880 DOI: 10.3389/fnhum.2016.00428] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 08/09/2016] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Emotional disturbance is a common complication of stroke significantly affecting functional recovery and quality of life. Identifying relevant neurophysiologic markers associated with post-stroke emotional disturbance may lead to a better understanding of this disabling condition, guiding the diagnosis, development of new interventions and the assessments of treatment response. METHODS Thirty-five subjects with chronic stroke were enrolled in this study. The emotion sub-domain of Stroke Impact Scale (SIS-Emotion) was used to assess post-stroke mood and emotional control. The relation between SIS-Emotion and neurophysiologic measures was assessed by using covariance mapping and univariate linear regression. Multivariate analyses were conducted to identify and adjust for potential confounders. Neurophysiologic measures included power asymmetry and coherence assessed by electroencephalography (EEG); and motor threshold, intracortical inhibition (ICI) and intracortical facilitation (ICF) measured by transcranial magnetic stimulation (TMS). RESULTS Lower scores on SIS-Emotion was associated with (1) frontal EEG power asymmetry in alpha and beta bands, (2) central EEG power asymmetry in alpha and theta bands, and (3) lower inter-hemispheric coherence over frontal and central areas in alpha band. SIS-Emotion also correlated with higher ICF and MT in the unlesioned hemisphere as measured by TMS. CONCLUSIONS To our knowledge, this is the first study using EEG and TMS to index neurophysiologic changes associated with post-stroke mood and emotional control. Our results suggest that inter-hemispheric imbalance measured by EEG power and coherence, as well as an increased ICF in the unlesioned hemisphere measured by TMS might be relevant markers associated with post-stroke mood and emotional control which can guide future studies investigating new diagnostic and treatment modalities in stroke rehabilitation.
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Affiliation(s)
- Deniz Doruk
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School Boston, MA, USA
| | - Marcel Simis
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical SchoolBoston, MA, USA; Physical and Rehabilitation Medicine Institute of the University of São Paulo, Medical School General HospitalSão Paulo, Brazil
| | - Marta Imamura
- Physical and Rehabilitation Medicine Institute of the University of São Paulo, Medical School General Hospital São Paulo, Brazil
| | - André R Brunoni
- Service of Interdisciplinary Neuromodulation, Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo São Paulo, Brazil
| | - Leon Morales-Quezada
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School Boston, MA, USA
| | - Renato Anghinah
- Physical and Rehabilitation Medicine Institute of the University of São Paulo, Medical School General Hospital São Paulo, Brazil
| | - Felipe Fregni
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical SchoolBoston, MA, USA; Physical and Rehabilitation Medicine Institute of the University of São Paulo, Medical School General HospitalSão Paulo, Brazil
| | - Linamara R Battistella
- Physical and Rehabilitation Medicine Institute of the University of São Paulo, Medical School General Hospital São Paulo, Brazil
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Kiper P, Szczudlik A, Venneri A, Stozek J, Luque-Moreno C, Opara J, Baba A, Agostini M, Turolla A. Computational models and motor learning paradigms: Could they provide insights for neuroplasticity after stroke? An overview. J Neurol Sci 2016; 369:141-148. [PMID: 27653881 DOI: 10.1016/j.jns.2016.08.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 01/08/2023]
Abstract
Computational approaches for modelling the central nervous system (CNS) aim to develop theories on processes occurring in the brain that allow the transformation of all information needed for the execution of motor acts. Computational models have been proposed in several fields, to interpret not only the CNS functioning, but also its efferent behaviour. Computational model theories can provide insights into neuromuscular and brain function allowing us to reach a deeper understanding of neuroplasticity. Neuroplasticity is the process occurring in the CNS that is able to permanently change both structure and function due to interaction with the external environment. To understand such a complex process several paradigms related to motor learning and computational modeling have been put forward. These paradigms have been explained through several internal model concepts, and supported by neurophysiological and neuroimaging studies. Therefore, it has been possible to make theories about the basis of different learning paradigms according to known computational models. Here we review the computational models and motor learning paradigms used to describe the CNS and neuromuscular functions, as well as their role in the recovery process. These theories have the potential to provide a way to rigorously explain all the potential of CNS learning, providing a basis for future clinical studies.
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Affiliation(s)
- Pawel Kiper
- Laboratory of Kinematics and Robotics, IRCCS San Camillo Hospital Foundation, via Alberoni 70, 30126 Venice, Italy.
| | - Andrzej Szczudlik
- Jagiellonian University Medical College, ul. Sw. Anny 12, 31-008 Krakow, Poland
| | - Annalena Venneri
- Laboratory of Kinematics and Robotics, IRCCS San Camillo Hospital Foundation, via Alberoni 70, 30126 Venice, Italy; Department of Neuroscience, The University of Sheffield, 385a Glossop Road, S10 2HQ Sheffield, UK
| | - Joanna Stozek
- The University of Physical Education, Al. Jana Pawla II 78, 31-571 Krakow, Poland
| | - Carlos Luque-Moreno
- Department of Physical Therapy, The University of Seville, C/Avicena S/N, 41009 Seville, Spain; Motion Analysis Laboratory, Virgen del Rocio Hospital, Avda. Manuel Siurot S/N, 41013 Seville, Spain
| | - Jozef Opara
- Academy of Physical Education, ul. Mikolowska 72a, 40-065 Katowice, Poland
| | - Alfonc Baba
- Laboratory of Kinematics and Robotics, IRCCS San Camillo Hospital Foundation, via Alberoni 70, 30126 Venice, Italy
| | - Michela Agostini
- Laboratory of Kinematics and Robotics, IRCCS San Camillo Hospital Foundation, via Alberoni 70, 30126 Venice, Italy
| | - Andrea Turolla
- Laboratory of Kinematics and Robotics, IRCCS San Camillo Hospital Foundation, via Alberoni 70, 30126 Venice, Italy; Department of Neuroscience, The University of Sheffield, 385a Glossop Road, S10 2HQ Sheffield, UK
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Abstract
In this review, we examine how tactile misperceptions provide evidence regarding body representations. First, we propose that tactile detection and localization are serial processes, in contrast to parallel processing hypotheses based on patients with numbsense. Second, we discuss how information in primary somatosensory maps projects to body size and shape representations to localize touch on the skin surface, and how responses after use-dependent plasticity reflect changes in this mapping. Third, we review situations in which our body representations are inconsistent with our actual body shape, specifically discussing phantom limb phenomena and anesthetization. We discuss problems with the traditional remapping hypothesis in amputees, factors that modulate perceived body size and shape, and how changes in perceived body form influence tactile localization. Finally, we review studies in which brain-damaged individuals perceive touch on the opposite side of the body, and demonstrate how interhemispheric mechanisms can give rise to these anomalous percepts.
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Affiliation(s)
- Jared Medina
- a Department of Psychology , University of Delaware , Newark , DE , USA
| | - H Branch Coslett
- b Department of Neurology, Center for Cognitive Neuroscience , University of Pennsylvania , Philadelphia , PA , USA
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Manganotti P, Acler M, Masiero S, Del Felice A. TMS-evoked N100 responses as a prognostic factor in acute stroke. FUNCTIONAL NEUROLOGY 2016; 30:125-30. [PMID: 26415785 DOI: 10.11138/fneur/2015.30.2.125] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Rehabilitation programs, to be efficiently tailored, need clear prognostic markers. In acute stroke, neurophysiological measures, such as motor evoked potentials (MEPs), have been proposed, although with discordant results. The aim of this study was to identify a reliable neurophysiological measure of recovery in acute post-stroke individuals by combining MEPs and the N100 component of transcranial magnetic stimulation-evoked potentials (TEPs). Nine acute post-stroke subjects were included. Clinical evaluation performed in the first week after the event included administration of the European Stroke Scale and Barthel Index and recording of MEPs and TEPs; administration of the clinical scales was repeated after one and three months. The presence/absence of MEPs and TEPs showed correlations with motor outcome. Individuals with a poorer outcome showed absence of both MEPs and TEPs; absence of MEPs alone was related to a partial recovery. Given the results of this exploratory study, further investigation is needed to define the accuracy of combined use of MEPs and TEPs as an approach for predicting motor recovery after acute stroke.
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Goodwill AM, Teo WP, Morgan P, Daly RM, Kidgell DJ. Bihemispheric-tDCS and Upper Limb Rehabilitation Improves Retention of Motor Function in Chronic Stroke: A Pilot Study. Front Hum Neurosci 2016; 10:258. [PMID: 27375456 PMCID: PMC4899474 DOI: 10.3389/fnhum.2016.00258] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/17/2016] [Indexed: 11/18/2022] Open
Abstract
Background: Single sessions of bihemispheric transcranial direct-current stimulation (bihemispheric-tDCS) with concurrent rehabilitation improves motor function in stroke survivors, which outlasts the stimulation period. However few studies have investigated the behavioral and neurophysiological adaptations following a multi-session intervention of bihemispheric-tDCS concurrent with rehabilitation. Objective: This pilot study explored the immediate and lasting effects of 3-weeks of bihemispheric-tDCS and upper limb (UL) rehabilitation on motor function and corticospinal plasticity in chronic stroke survivors. Methods: Fifteen chronic stroke survivors underwent 3-weeks of UL rehabilitation with sham or real bihemispheric-tDCS. UL motor function was assessed via the Motor Assessment Scale (MAS), Tardieu Scale and grip strength. Corticospinal plasticity was indexed by motor evoked potentials (MEPs), cortical silent period (CSP) and short-interval intracortical inhibition (SICI) recorded from the paretic and non-paretic ULs, using transcranial magnetic stimulation (TMS). Measures were taken at baseline, 48 h post and 3-weeks following (follow-up) the intervention. Results: MAS improved following both real-tDCS (62%) and sham-tDCS (43%, P < 0.001), however at 3-weeks follow-up, the real-tDCS condition retained these newly regained motor skills to a greater degree than sham-tDCS (real-tDCS 64%, sham-tDCS 21%, P = 0.002). MEP amplitudes from the paretic UL increased for real-tDCS (46%: P < 0.001) and were maintained at 3-weeks follow-up (38%: P = 0.03), whereas no changes were observed with sham-tDCS. No changes in MEPs from the non-paretic nor SICI from the paretic UL were observed for either group. SICI from the non-paretic UL was greater at follow-up, for real-tDCS (27%: P = 0.04). CSP from the non-paretic UL increased by 33% following the intervention for real-tDCS compared with sham-tDCS (P = 0.04), which was maintained at 3-weeks follow-up (24%: P = 0.04). Conclusion: bihemispheric-tDCS improved retention of gains in motor function, which appears to be modulated through intracortical inhibitory pathways in the contralesional primary motor cortex (M1). The findings provide preliminary evidence for the benefits of bihemispheric-tDCS during rehabilitation. Larger clinical trials are warranted to examine long term benefits of bihemispheric-tDCS in a stroke affected population.
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Affiliation(s)
- Alicia M Goodwill
- Institute for Physical Activity and Nutrition, Deakin University Melbourne, VIC, Australia
| | - Wei-Peng Teo
- Institute for Physical Activity and Nutrition, Deakin University Melbourne, VIC, Australia
| | - Prue Morgan
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Science, Monash University Frankston, VIC, Australia
| | - Robin M Daly
- Institute for Physical Activity and Nutrition, Deakin University Melbourne, VIC, Australia
| | - Dawson J Kidgell
- Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University Melbourne, VIC, Australia
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Enderby P, Pandyan A, Bowen A, Hearnden D, Ashburn A, Conroy P, Logan P, Thompson C, Winter J. Accessing rehabilitation after stroke – a guessing game? Disabil Rehabil 2016; 39:709-713. [DOI: 10.3109/09638288.2016.1160448] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Pam Enderby
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - Anand Pandyan
- Institute for Science and Technology in Medicine & School of Health and Rehabilitation, Keele University, Keele, UK
| | - Audrey Bowen
- Stroke Research, MAHSC, University of Manchester, Salford, UK
| | - David Hearnden
- Dudley MBC Adult Care, Dudley Social Services, Dudley, UK
| | - Ann Ashburn
- Faculty of Health Science, University of Southampton, Southampton, UK
| | - Paul Conroy
- Stroke Research, MAHSC, University of Manchester, Salford, UK
| | - Pip Logan
- Division of Rehabilitation and Ageing, School of Community Health Sciences, University of Nottingham, Nottingham, UK
| | - Carl Thompson
- School of Healthcare, University of Leeds, Leeds, UK
| | - Jacqueline Winter
- Institute for Science and Technology in Medicine & School of Health and Rehabilitation, Keele University, Keele, UK
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Xu Y, Hou QH, Russell SD, Bennett BC, Sellers AJ, Lin Q, Huang DF. Neuroplasticity in post-stroke gait recovery and noninvasive brain stimulation. Neural Regen Res 2016; 10:2072-80. [PMID: 26889202 PMCID: PMC4730838 DOI: 10.4103/1673-5374.172329] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Gait disorders drastically affect the quality of life of stroke survivors, making post-stroke rehabilitation an important research focus. Noninvasive brain stimulation has potential in facilitating neuroplasticity and improving post-stroke gait impairment. However, a large inter-individual variability in the response to noninvasive brain stimulation interventions has been increasingly recognized. We first review the neurophysiology of human gait and post-stroke neuroplasticity for gait recovery, and then discuss how noninvasive brain stimulation techniques could be utilized to enhance gait recovery. While post-stroke neuroplasticity for gait recovery is characterized by use-dependent plasticity, it evolves over time, is idiosyncratic, and may develop maladaptive elements. Furthermore, noninvasive brain stimulation has limited reach capability and is facilitative-only in nature. Therefore, we recommend that noninvasive brain stimulation be used adjunctively with rehabilitation training and other concurrent neuroplasticity facilitation techniques. Additionally, when noninvasive brain stimulation is applied for the rehabilitation of gait impairment in stroke survivors, stimulation montages should be customized according to the specific types of neuroplasticity found in each individual. This could be done using multiple mapping techniques.
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Affiliation(s)
- Yi Xu
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China; Guangdong Provincial Engineering Technology Research Center for Rehabilitation Medicine and Clinical Translation, Guangzhou, Guangdong Province, China; Motion Analysis and Motor Performance Laboratory, Department of Orthopedics and Mechanical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Qing-Hua Hou
- Department of Neurology, Guangdong No.2 Provincial People's Hospital, Guangzhou, Guangdong Province, China
| | - Shawn D Russell
- Motion Analysis and Motor Performance Laboratory, Department of Orthopedics and Mechanical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Bradford C Bennett
- H.C Sweere Center for Clinical Biomechanics and Applied Ergonomics, Northwestern Health Science University, Bloomington, MN, USA
| | - Andrew J Sellers
- Department of Radiology, Naval Medical Center Portsmouth, Portsmouth, VA, USA
| | - Qiang Lin
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China; Guangdong Provincial Engineering Technology Research Center for Rehabilitation Medicine and Clinical Translation, Guangzhou, Guangdong Province, China
| | - Dong-Feng Huang
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China; Guangdong Provincial Engineering Technology Research Center for Rehabilitation Medicine and Clinical Translation, Guangzhou, Guangdong Province, China
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48
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Shiner CT, Tang H, Johnson BW, McNulty PA. Cortical beta oscillations and motor thresholds differ across the spectrum of post-stroke motor impairment, a preliminary MEG and TMS study. Brain Res 2015; 1629:26-37. [DOI: 10.1016/j.brainres.2015.09.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/25/2015] [Accepted: 09/29/2015] [Indexed: 01/27/2023]
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49
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Abstract
In acute stroke, the major factor for recovery is the early use of thrombolysis aimed at arterial recanalization and reperfusion of ischemic brain tissue. Subsequently, neurorehabilitative training critically improves clinical recovery due to augmention of postlesional plasticity. Neuroimaging and electrophysiology studies have revealed that the location and volume of the stroke lesion, the affection of nerve fiber tracts, as well as functional and structural changes in the perilesional tissue and in large-scale bihemispheric networks are relevant biomarkers of post-stroke recovery. However, associated disorders, such as mood disorders, epilepsy, and neurodegenerative diseases, may induce secondary cerebral changes or aggravate the functional deficits and, thereby, compromise the potential for recovery.
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Affiliation(s)
- Rüdiger J Seitz
- Department of Neurology, Centre of Neurology and Neuropsychiatry, LVR-Klinikum Düsseldorf, Heinrich-Heine-University Düsseldorf , Düsseldorf , Germany ; Biomedical Research Centre, Heinrich-Heine-University Düsseldorf , Düsseldorf , Germany ; Florey Institute of Neuroscience and Mental Health, University of Melbourne , Parkville, VIC , Australia
| | - Geoffrey A Donnan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne , Parkville, VIC , Australia
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50
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Ng KL, Gibson EM, Hubbard R, Yang J, Caffo B, O'Brien RJ, Krakauer JW, Zeiler SR. Fluoxetine Maintains a State of Heightened Responsiveness to Motor Training Early After Stroke in a Mouse Model. Stroke 2015; 46:2951-60. [PMID: 26294676 PMCID: PMC4934654 DOI: 10.1161/strokeaha.115.010471] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/16/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND PURPOSE Data from both humans and animal models suggest that most recovery from motor impairment after stroke occurs in a sensitive period that lasts only weeks and is mediated, in part, by an increased responsiveness to training. Here, we used a mouse model of focal cortical stroke to test 2 hypotheses. First, we investigated whether responsiveness to training decreases over time after stroke. Second, we tested whether fluoxetine, which can influence synaptic plasticity and stroke recovery, can prolong the period over which large training-related gains can be elicited after stroke. METHODS Mice were trained to perform a skilled prehension task to an asymptotic level of performance after which they underwent stroke induction in the caudal forelimb area. The mice were then retrained after a 1- or 7-day delay with and without fluoxetine. RESULTS Recovery of prehension after a caudal forelimb area stroke was complete if training was initiated 1 day after stroke but incomplete if it was delayed by 7 days. In contrast, if fluoxetine was administered at 24 hours after stroke, then complete recovery of prehension was observed even with the 7-day training delay. Fluoxetine seemed to mediate its beneficial effect by reducing inhibitory interneuron expression in intact premotor cortex rather than through effects on infarct volume or cell death. CONCLUSIONS There is a gradient of diminishing responsiveness to motor training over the first week after stroke. Fluoxetine can overcome this gradient and maintain maximal levels of responsiveness to training even 7 days after stroke.
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Affiliation(s)
- Kwan L Ng
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - Ellen M Gibson
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - Robert Hubbard
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - Juemin Yang
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - Brian Caffo
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - Richard J O'Brien
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - John W Krakauer
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.)
| | - Steven R Zeiler
- From the Departments of Neurology (K.L.N., E.M.G., R.H., J.W.K., S.R.Z.) and Neuroscience (J.W.K.), Johns Hopkins University, Baltimore, MD; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (J.Y., B.C.); and Department of Neurology, Duke University, Durham, NC (R.J.O.).
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