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Pascarella A, Bruni V, Armonaite K, Porcaro C, Conti L, Cecconi F, Paulon L, Vitulano D, Tecchio F. Functional balance at rest of hemispheric homologs assessed via normalized compression distance. Front Neurosci 2024; 17:1261701. [PMID: 38333603 PMCID: PMC10851083 DOI: 10.3389/fnins.2023.1261701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/13/2023] [Indexed: 02/10/2024] Open
Abstract
Introduction The formation and functioning of neural networks hinge critically on the balance between structurally homologous areas in the hemispheres. This balance, reflecting their physiological relationship, is fundamental for learning processes. In our study, we explore this functional homology in the resting state, employing a complexity measure that accounts for the temporal patterns in neurodynamics. Methods We used Normalized Compression Distance (NCD) to assess the similarity over time, neurodynamics, of the somatosensory areas associated with hand perception (S1). This assessment was conducted using magnetoencephalography (MEG) in conjunction with Functional Source Separation (FSS). Our primary hypothesis posited that neurodynamic similarity would be more pronounced within individual subjects than across different individuals. Additionally, we investigated whether this similarity is influenced by hemisphere or age at a population level. Results Our findings validate the hypothesis, indicating that NCD is a robust tool for capturing balanced functional homology between hemispheric regions. Notably, we observed a higher degree of neurodynamic similarity in the population within the left hemisphere compared to the right. Also, we found that intra-subject functional homology displayed greater variability in older individuals than in younger ones. Discussion Our approach could be instrumental in investigating chronic neurological conditions marked by imbalances in brain activity, such as depression, addiction, fatigue, and epilepsy. It holds potential for aiding in the development of new therapeutic strategies tailored to these complex conditions, though further research is needed to fully realize this potential.
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Affiliation(s)
- Annalisa Pascarella
- Istituto per le Applicazioni del Calcolo ‘Mauro Picone’, National Research Council of Italy, Rome, Italy
| | - Vittoria Bruni
- Istituto per le Applicazioni del Calcolo ‘Mauro Picone’, National Research Council of Italy, Rome, Italy
- Department of Basic and Applied Science for Engineering (SBAI), University of Rome ‘Sapienza’, Rome, Italy
| | | | - Camillo Porcaro
- Department of Neuroscience and Padova Neuroscience Center, University of Padua, Padua, Italy
- Laboratory of Electrophysiology for Translational neuroScience and Laboratory for Agent Based Social Simulation, Institute of Cognitive Sciences and Technologies, National Research Council of Italy, Rome, Italy
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham, United Kingdom
| | - Livio Conti
- Faculty of Engineering, Uninettuno University, Rome, Italy
| | - Federico Cecconi
- Laboratory of Electrophysiology for Translational neuroScience and Laboratory for Agent Based Social Simulation, Institute of Cognitive Sciences and Technologies, National Research Council of Italy, Rome, Italy
| | - Luca Paulon
- Laboratory of Electrophysiology for Translational neuroScience and Laboratory for Agent Based Social Simulation, Institute of Cognitive Sciences and Technologies, National Research Council of Italy, Rome, Italy
- Luca Paulon, Independent Researcher, Rome, Italy
| | - Domenico Vitulano
- Department of Basic and Applied Science for Engineering (SBAI), University of Rome ‘Sapienza’, Rome, Italy
| | - Franca Tecchio
- Laboratory of Electrophysiology for Translational neuroScience and Laboratory for Agent Based Social Simulation, Institute of Cognitive Sciences and Technologies, National Research Council of Italy, Rome, Italy
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2
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Chen Z, Yan T, Wu J, Liu Y, Zhang C, Cui T. Sensorimotor rhythm and muscle activity in patients with stroke using mobile serious games to assist upper extremity rehabilitation. FRONTIERS IN REHABILITATION SCIENCES 2023; 4:1234216. [PMID: 38046523 PMCID: PMC10690953 DOI: 10.3389/fresc.2023.1234216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 10/30/2023] [Indexed: 12/05/2023]
Abstract
Introduction Exercise rehabilitation is crucial for neurological recovery in hemiplegia-induced upper limb dysfunction. Technology-assisted cortical activation in sensorimotor areas has shown potential for restoring motor function. This study assessed the feasibility of mobile serious games for stroke patients' motor rehabilitation. Methods A dedicated mobile application targeted shoulder, elbow, and wrist training. Twelve stroke survivors attempted a motor task under two conditions: serious mobile game-assisted and conventional rehabilitation. Electroencephalography and electromyography measured the therapy effects. Results Patients undergoing game-assisted rehabilitation showed stronger event-related desynchronization (ERD) in the contralateral hemisphere's motor perception areas compared to conventional rehabilitation (p < 0.05). RMS was notably higher in game-assisted rehabilitation, particularly in shoulder training (p < 0.05). Discussion Serious mobile game rehabilitation activated the motor cortex without directly improving muscle activity. This suggests its potential in neurological recovery for stroke patients.
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Affiliation(s)
- Zihe Chen
- School of Art, Southeast University, Nanjing, China
| | - Tingmin Yan
- School of Art, Southeast University, Nanjing, China
| | - Jinchun Wu
- School of Mechanical Engineering, Southeast University, Nanjing, China
| | - Yixuan Liu
- School of Mechanical Engineering, Southeast University, Nanjing, China
| | - Chunyun Zhang
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Tianjian Cui
- School of Art, Southeast University, Nanjing, China
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3
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Torres-Simon L, Cuesta P, del Cerro-Leon A, Chino B, Orozco LH, Marsh EB, Gil P, Maestu F. The effects of white matter hyperintensities on MEG power spectra in population with mild cognitive impairment. Front Hum Neurosci 2023; 17:1068216. [PMID: 36875239 PMCID: PMC9977191 DOI: 10.3389/fnhum.2023.1068216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/23/2023] [Indexed: 02/17/2023] Open
Abstract
Cerebrovascular disease is responsible for up to 20% of cases of dementia worldwide, but also it is a major comorbid contributor to the progression of other neurodegenerative diseases, like Alzheimer's disease. White matter hyperintensities (WMH) are the most prevalent imaging marker in cerebrovascular disease. The presence and progression of WMH in the brain have been associated with general cognitive impairment and the risk to develop all types of dementia. The aim of this piece of work is the assessment of brain functional differences in an MCI population based on the WMH volume. One-hundred and twenty-nine individuals with mild cognitive impairment (MCI) underwent a neuropsychological evaluation, MRI assessment (T1 and Flair), and MEG recordings (5 min of eyes closed resting state). Those participants were further classified into vascular MCI (vMCI; n = 61, mean age 75 ± 4 years, 35 females) or non-vascular MCI (nvMCI; n = 56, mean age 72 ± 5 years, 36 females) according to their WMH total volume, assessed with an automatic detection toolbox, LST (SPM12). We used a completely data-driven approach to evaluate the differences in the power spectra between the groups. Interestingly, three clusters emerged: One cluster with widespread larger theta power and two clusters located in both temporal regions with smaller beta power for vMCI compared to nvMCI. Those power signatures were also associated with cognitive performance and hippocampal volume. Early identification and classification of dementia pathogenesis is a crucially important goal for the search for more effective management approaches. These findings could help to understand and try to palliate the contribution of WMH to particular symptoms in mixed dementia progress.
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Affiliation(s)
- Lucia Torres-Simon
- Center of Cognitive and Computational Neuroscience, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Pablo Cuesta
- Center of Cognitive and Computational Neuroscience, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Department of Radiology, Rehabilitation, and Physiotherapy, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto de investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Alberto del Cerro-Leon
- Center of Cognitive and Computational Neuroscience, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Brenda Chino
- Center of Cognitive and Computational Neuroscience, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Institute of Neuroscience, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | - Lucia H. Orozco
- Center of Cognitive and Computational Neuroscience, Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Elisabeth B. Marsh
- Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Pedro Gil
- Instituto de investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
- Department of Geriatric Medicine, Hospital Universitario San Carlos, Madrid, Spain
| | - Fernando Maestu
- Center of Cognitive and Computational Neuroscience, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Universidad Complutense de Madrid (UCM), Madrid, Spain
- Instituto de investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
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4
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Sato Y, Schmitt O, Ip Z, Rabiller G, Omodaka S, Tominaga T, Yazdan-Shahmorad A, Liu J. Pathological changes of brain oscillations following ischemic stroke. J Cereb Blood Flow Metab 2022; 42:1753-1776. [PMID: 35754347 PMCID: PMC9536122 DOI: 10.1177/0271678x221105677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/01/2022] [Accepted: 05/17/2022] [Indexed: 11/16/2022]
Abstract
Brain oscillations recorded in the extracellular space are among the most important aspects of neurophysiology data reflecting the activity and function of neurons in a population or a network. The signal strength and patterns of brain oscillations can be powerful biomarkers used for disease detection and prediction of the recovery of function. Electrophysiological signals can also serve as an index for many cutting-edge technologies aiming to interface between the nervous system and neuroprosthetic devices and to monitor the efficacy of boosting neural activity. In this review, we provided an overview of the basic knowledge regarding local field potential, electro- or magneto- encephalography signals, and their biological relevance, followed by a summary of the findings reported in various clinical and experimental stroke studies. We reviewed evidence of stroke-induced changes in hippocampal oscillations and disruption of communication between brain networks as potential mechanisms underlying post-stroke cognitive dysfunction. We also discussed the promise of brain stimulation in promoting post stroke functional recovery via restoring neural activity and enhancing brain plasticity.
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Affiliation(s)
- Yoshimichi Sato
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Oliver Schmitt
- Department of Anatomy, Medical School Hamburg, University of Applied Sciences and Medical University, Hamburg, Germany
| | - Zachary Ip
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Gratianne Rabiller
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
| | - Shunsuke Omodaka
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Azadeh Yazdan-Shahmorad
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Jialing Liu
- Department of Neurological Surgery, UCSF, San Francisco, CA, USA
- Department of Neurological Surgery, SFVAMC, San Francisco, CA, USA
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5
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Kulasingham JP, Brodbeck C, Khan S, Marsh EB, Simon JZ. Bilaterally Reduced Rolandic Beta Band Activity in Minor Stroke Patients. Front Neurol 2022; 13:819603. [PMID: 35418932 PMCID: PMC8996122 DOI: 10.3389/fneur.2022.819603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 02/14/2022] [Indexed: 11/24/2022] Open
Abstract
Stroke patients with hemiparesis display decreased beta band (13–25 Hz) rolandic activity, correlating to impaired motor function. However, clinically, patients without significant weakness, with small lesions far from sensorimotor cortex, exhibit bilateral decreased motor dexterity and slowed reaction times. We investigate whether these minor stroke patients also display abnormal beta band activity. Magnetoencephalographic (MEG) data were collected from nine minor stroke patients (NIHSS < 4) without significant hemiparesis, at ~1 and ~6 months postinfarct, and eight age-similar controls. Rolandic relative beta power during matching tasks and resting state, and Beta Event Related (De)Synchronization (ERD/ERS) during button press responses were analyzed. Regardless of lesion location, patients had significantly reduced relative beta power and ERS compared to controls. Abnormalities persisted over visits, and were present in both ipsi- and contra-lesional hemispheres, consistent with bilateral impairments in motor dexterity and speed. Minor stroke patients without severe weakness display reduced rolandic beta band activity in both hemispheres, which may be linked to bilaterally impaired dexterity and processing speed, implicating global connectivity dysfunction affecting sensorimotor cortex independent of lesion location. Findings not only illustrate global network disruption after minor stroke, but suggest rolandic beta band activity may be a potential biomarker and treatment target, even for minor stroke patients with small lesions far from sensorimotor areas.
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Affiliation(s)
- Joshua P Kulasingham
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, United States
| | - Christian Brodbeck
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
| | - Sheena Khan
- Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Elisabeth B Marsh
- Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Jonathan Z Simon
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, United States.,Department of Biology, University of Maryland, College Park, MD, United States.,Institute for Systems Research, University of Maryland, College Park, MD, United States
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6
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Corticomuscular coherence dependence on body side and visual feedback. Neuroscience 2022; 490:144-154. [DOI: 10.1016/j.neuroscience.2022.02.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 02/02/2022] [Accepted: 02/17/2022] [Indexed: 12/26/2022]
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7
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Fanciullacci C, Panarese A, Spina V, Lassi M, Mazzoni A, Artoni F, Micera S, Chisari C. Connectivity Measures Differentiate Cortical and Subcortical Sub-Acute Ischemic Stroke Patients. Front Hum Neurosci 2021; 15:669915. [PMID: 34276326 PMCID: PMC8281978 DOI: 10.3389/fnhum.2021.669915] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/08/2021] [Indexed: 01/14/2023] Open
Abstract
Brain lesions caused by cerebral ischemia lead to network disturbances in both hemispheres, causing a subsequent reorganization of functional connectivity both locally and remotely with respect to the injury. Quantitative electroencephalography (qEEG) methods have long been used for exploring brain electrical activity and functional connectivity modifications after stroke. However, results obtained so far are not univocal. Here, we used basic and advanced EEG methods to characterize how brain activity and functional connectivity change after stroke. Thirty-three unilateral post stroke patients in the sub-acute phase and ten neurologically intact age-matched right-handed subjects were enrolled. Patients were subdivided into two groups based on lesion location: cortico-subcortical (CS, n = 18) and subcortical (S, n = 15), respectively. Stroke patients were evaluated in the period ranging from 45 days since the acute event (T0) up to 3 months after stroke (T1) with both neurophysiological (resting state EEG) and clinical assessment (Barthel Index, BI) measures, while healthy subjects were evaluated once. Brain power at T0 was similar between the two groups of patients in all frequency bands considered (δ, θ, α, and β). However, evolution of θ-band power over time was different, with a normalization only in the CS group. Instead, average connectivity and specific network measures (Integration, Segregation, and Small-worldness) in the β-band at T0 were significantly different between the two groups. The connectivity and network measures at T0 also appear to have a predictive role in functional recovery (BI T1-T0), again group-dependent. The results obtained in this study showed that connectivity measures and correlations between EEG features and recovery depend on lesion location. These data, if confirmed in further studies, on the one hand could explain the heterogeneity of results so far observed in previous studies, on the other hand they could be used by researchers as biomarkers predicting spontaneous recovery, to select homogenous groups of patients for the inclusion in clinical trials.
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Affiliation(s)
- Chiara Fanciullacci
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.,Unit of Neurorehabilitation, Department of Medical Specialties, University Hospital of Pisa, Pisa, Italy
| | | | - Vincenzo Spina
- Unit of Neurorehabilitation, Department of Medical Specialties, University Hospital of Pisa, Pisa, Italy
| | - Michael Lassi
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Alberto Mazzoni
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fiorenzo Artoni
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.,Translational Neural Engineering Laboratory, Center for Neuroprosthetics, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Silvestro Micera
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.,Translational Neural Engineering Laboratory, Center for Neuroprosthetics, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Carmelo Chisari
- Unit of Neurorehabilitation, Department of Medical Specialties, University Hospital of Pisa, Pisa, Italy
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8
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Kim JA, Davis KD. Magnetoencephalography: physics, techniques, and applications in the basic and clinical neurosciences. J Neurophysiol 2021; 125:938-956. [PMID: 33567968 DOI: 10.1152/jn.00530.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetoencephalography (MEG) is a technique used to measure the magnetic fields generated from neuronal activity in the brain. MEG has a high temporal resolution on the order of milliseconds and provides a more direct measure of brain activity when compared with hemodynamic-based neuroimaging methods such as magnetic resonance imaging and positron emission tomography. The current review focuses on basic features of MEG such as the instrumentation and the physics that are integral to the signals that can be measured, and the principles of source localization techniques, particularly the physics of beamforming and the techniques that are used to localize the signal of interest. In addition, we review several metrics that can be used to assess functional coupling in MEG and describe the advantages and disadvantages of each approach. Lastly, we discuss the current and future applications of MEG.
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Affiliation(s)
- Junseok A Kim
- Division of Brain, Imaging and Behaviour, Krembil Brain Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karen D Davis
- Division of Brain, Imaging and Behaviour, Krembil Brain Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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9
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Roy AV, Thai M, Klimes-Dougan B, Schreiner MW, Mueller BA, Albott CS, Lim KO, Fiecas M, Tye SJ, Cullen KR. Brain entropy and neurotrophic molecular markers accompanying clinical improvement after ketamine: Preliminary evidence in adolescents with treatment-resistant depression. J Psychopharmacol 2021; 35:168-177. [PMID: 32643995 PMCID: PMC8569740 DOI: 10.1177/0269881120928203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Current theory suggests that treatment-resistant depression (TRD) involves impaired neuroplasticity resulting in cognitive and neural rigidity, and that clinical improvement may require increasing brain flexibility and adaptability. AIMS In this hypothesis-generating study, we sought to identify preliminary evidence of brain flexibility correlates of clinical change within the context of an open-label ketamine trial in adolescents with TRD, focusing on two promising candidate markers of neural flexibility: (a) entropy of resting-state functional magnetic resonance imaging (fMRI) signals; and (b) insulin-stimulated phosphorylation of mammalian target of rapamycin (mTOR) and glycogen synthase-3-beta (GSK3β) in peripheral blood mononuclear cells. METHODS We collected resting-state functional magnetic resonance imaging data and blood samples from 13 adolescents with TRD before and after a series of six ketamine infusions over 2 weeks. Usable pre/post ketamine data were available from 11 adolescents for imaging and from 10 adolescents for molecular signaling. We examined correlations between treatment response and changes in the central and peripheral flexibility markers. RESULTS Depression reduction correlated with increased nucleus accumbens entropy. Follow-up analyses suggested that physiological changes were associated with treatment response. In contrast to treatment non-responders (n=6), responders (n=5) showed greater increase in nucleus accumbens entropy after ketamine, together with greater post-treatment insulin/mTOR/GSK3β signaling. CONCLUSIONS These data provide preliminary evidence that changes in neural flexibility may underlie symptom relief in adolescents with TRD following ketamine. Future research with adequately powered samples is needed to confirm resting-state entropy and insulin-stimulated mTOR and GSK3β as brain flexibility markers and candidate targets for future clinical trials. CLINICAL TRIAL NAME Ketamine in adolescents with treatment-resistant depressionURL: https://clinicaltrials.gov/ct2/show/NCT02078817Registration number: NCT02078817.
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Affiliation(s)
- Abhrajeet V Roy
- Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, USA
| | - Michelle Thai
- Department of Psychology, College of Liberal Arts, University of Minnesota, Minneapolis, USA
| | - Bonnie Klimes-Dougan
- Department of Psychology, College of Liberal Arts, University of Minnesota, Minneapolis, USA
| | | | - Bryon A Mueller
- Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, USA
| | - Christina Sophia Albott
- Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, USA
| | - Kelvin O Lim
- Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, USA
| | - Mark Fiecas
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, USA
| | - Susannah J Tye
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Kathryn R Cullen
- Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, USA
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10
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Chiarelli AM, Croce P, Assenza G, Merla A, Granata G, Giannantoni NM, Pizzella V, Tecchio F, Zappasodi F. Electroencephalography-Derived Prognosis of Functional Recovery in Acute Stroke Through Machine Learning Approaches. Int J Neural Syst 2020; 30:2050067. [PMID: 33236654 DOI: 10.1142/s0129065720500677] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Stroke, if not lethal, is a primary cause of disability. Early assessment of markers of recovery can allow personalized interventions; however, it is difficult to deliver indexes in the acute phase able to predict recovery. In this perspective, evaluation of electrical brain activity may provide useful information. A machine learning approach was explored here to predict post-stroke recovery relying on multi-channel electroencephalographic (EEG) recordings of few minutes performed at rest. A data-driven model, based on partial least square (PLS) regression, was trained on 19-channel EEG recordings performed within 10 days after mono-hemispheric stroke in 101 patients. The band-wise (delta: 1-4[Formula: see text]Hz, theta: 4-7[Formula: see text]Hz, alpha: 8-14[Formula: see text]Hz and beta: 15-30[Formula: see text]Hz) EEG effective powers were used as features to predict the recovery at 6 months (based on clinical status evaluated through the NIH Stroke Scale, NIHSS) in an optimized and cross-validated framework. In order to exploit the multimodal contribution to prognosis, the EEG-based prediction of recovery was combined with NIHSS scores in the acute phase and both were fed to a nonlinear support vector regressor (SVR). The prediction performance of EEG was at least as good as that of the acute clinical status scores. A posteriori evaluation of the features exploited by the analysis highlighted a lower delta and higher alpha activity in patients showing a positive outcome, independently of the affected hemisphere. The multimodal approach showed better prediction capabilities compared to the acute NIHSS scores alone ([Formula: see text] versus [Formula: see text], AUC = 0.80 versus AUC = 0.70, [Formula: see text]). The multimodal and multivariate model can be used in acute phase to infer recovery relying on standard EEG recordings of few minutes performed at rest together with clinical assessment, to be exploited for early and personalized therapies. The easiness of performing EEG may allow such an approach to become a standard-of-care and, thanks to the increasing number of labeled samples, further improving the model predictive power.
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Affiliation(s)
- Antonio Maria Chiarelli
- Department of Neuroscience, Imaging and Clinical Sciences and the Institute for Advanced Biomedical Technologies, Università G. d'Annunzio, Chieti, 66100, Italy
| | - Pierpaolo Croce
- Department of Neuroscience, Imaging and Clinical Sciences and the Institute for Advanced Biomedical Technologies, Università G. d'Annunzio, Chieti, 66100, Italy
| | - Giovanni Assenza
- Neurology, Neurophysiology and Neurobiology Unit, Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy
| | - Arcangelo Merla
- Department of Neuroscience, Imaging and Clinical Sciences and the Institute for Advanced Biomedical Technologies, Università G. d'Annunzio, Chieti, 66100, Italy
| | - Giuseppe Granata
- Fondazione Policlinico A. Gemelli IRCCS, Catholic University of Sacred Heart, Rome, Italy
| | | | - Vittorio Pizzella
- Department of Neuroscience, Imaging and Clinical Sciences and the Institute for Advanced Biomedical Technologies, Università G. d'Annunzio, Chieti, 66100, Italy
| | - Franca Tecchio
- Laboratory of Electrophysiology for Translational NeuroScience (LET'S), Istituto di Scienze e Teconologie della Cognizione (ISTC) - Consiglio Nazionale delle Ricerche (CNR), Rome, Italy
| | - Filippo Zappasodi
- Department of Neuroscience, Imaging and Clinical Sciences and the Institute for Advanced Biomedical Technologies, Università G. d'Annunzio, Chieti, 66100, Italy
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11
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Roy S, Rathee D, Chowdhury A, McCreadie K, Prasad G. Assessing impact of channel selection on decoding of motor and cognitive imagery from MEG data. J Neural Eng 2020; 17:056037. [PMID: 32998113 DOI: 10.1088/1741-2552/abbd21] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Magnetoencephalography (MEG) based brain-computer interface (BCI) involves a large number of sensors allowing better spatiotemporal resolution for assessing brain activity patterns. There have been many efforts to develop BCI using MEG with high accuracy, though an increase in the number of channels (NoC) means an increase in computational complexity. However, not all sensors necessarily contribute significantly to an increase in classification accuracy (CA) and specifically in the case of MEG-based BCI no channel selection methodology has been performed. Therefore, this study investigates the effect of channel selection on the performance of MEG-based BCI. APPROACH MEG data were recorded for two sessions from 15 healthy participants performing motor imagery, cognitive imagery and a mixed imagery task pair using a unique paradigm. Performance of four state-of-the-art channel selection methods (i.e. Class-Correlation, ReliefF, Random Forest, and Infinite Latent Feature Selection were applied across six binary tasks in three different frequency bands) were evaluated in this study on two state-of-the-art features, i.e. bandpower and common spatial pattern (CSP). MAIN RESULTS All four methods provided a statistically significant increase in CA compared to a baseline method using all gradiometer sensors, i.e. 204 channels with band-power features from alpha (8-12 Hz), beta (13-30 Hz), or broadband (α + β) (8-30 Hz). It is also observed that the alpha frequency band performed better than the beta and broadband frequency bands. The performance of the beta band gave the lowest CA compared with the other two bands. Channel selection improved accuracy irrespective of feature types. Moreover, all the methods reduced the NoC significantly, from 204 to a range of 1-25, using bandpower as a feature and from 15 to 105 for CSP. The optimal channel number also varied not only in each session but also for each participant. Reducing the NoC will help to decrease the computational cost and maintain numerical stability in cases of low trial numbers. SIGNIFICANCE The study showed significant improvement in performance of MEG-BCI with channel selection irrespective of feature type and hence can be successfully applied for BCI applications.
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Affiliation(s)
- Sujit Roy
- School of Computing, Engineering & Intelligent Systems, Ulster University, Derry, Londonderry, United Kingdom
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12
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Foldes ST, Boninger ML, Weber DJ, Collinger JL. Effects of MEG-based neurofeedback for hand rehabilitation after tetraplegia: preliminary findings in cortical modulations and grip strength. J Neural Eng 2020; 17:026019. [PMID: 32135525 DOI: 10.1088/1741-2552/ab7cfb] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Neurofeedback (NF) trains people to volitionally modulate their cortical activity to affect a behavioral outcome. We evaluated the feasibility of using NF to improve hand function after chronic cervical-level spinal cord injury (SCI) using biologically-relevant visual feedback of motor-related brain activity and an intuitive control scheme. APPROACH The NF system acquired magnetoencephalography (MEG) data in real-time to provide feedback of event-related desynchronization (ERD) measured over the sensorimotor cortex during attempted hand grasping. During brain control, stronger ERD resulting from attempted grasping drove the virtual hand towards a more closed grasp, while less ERD drove the hand more open. MAIN RESULTS Eight individuals with partial or complete hand impairment due to chronic SCI controlled the NF to perform a grasping task that increased in difficulty as the participants achieved success. During their first NF session, participants achieved an average success rate of 63.7 ± 6.4% (chance level of 13.9%). After as few as one intervention session, four of the seven individuals evaluated for ERD changes had significantly strengthened ERD and three of the four participants with measurable grip strength prior to NF had increased grip strength. Interestingly, both individuals who participated in a longer-term study (i.e. >8 NF sessions) had improved grip strength and significantly strengthened ERD. SIGNIFICANCE This study demonstrates that MEG-based NF training can change brain activity in individuals with hand impairment due to SCI and has the potential to induce acute changes in grip strength. Future studies will evaluate whether neuroplasticity induced with long term NF can improve hand function for those with moderate impairment.
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Affiliation(s)
- Stephen T Foldes
- VA Pittsburgh Healthcare System, Pittsburgh, PA, United States of America. Rehab Neural Engineering Labs, Departments of Physical Medicine and Rehabilitation and Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America. Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America. Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, United States of America
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13
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Bulubas L, Sardesh N, Traut T, Findlay A, Mizuiri D, Honma SM, Krieg SM, Berger MS, Nagarajan SS, Tarapore PE. Motor Cortical Network Plasticity in Patients With Recurrent Brain Tumors. Front Hum Neurosci 2020; 14:118. [PMID: 32317952 PMCID: PMC7146050 DOI: 10.3389/fnhum.2020.00118] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/16/2020] [Indexed: 12/15/2022] Open
Abstract
Objective: The adult brain’s potential for plastic reorganization is an important mechanism for the preservation and restoration of function in patients with primary glial neoplasm. Patients with recurrent brain tumors requiring multiple interventions over time present an opportunity to examine brain reorganization. Magnetoencephalography (MEG) is a noninvasive imaging modality that can be used for motor cortical network mapping which, when performed at regular intervals, offers insight into this process of reorganization. Utilizing MEG-based motor mapping, we sought to characterize the reorganization of motor cortical networks over time in a cohort of 78 patients with recurrent glioma. Methods: MEG-based motor cortical maps were obtained by measuring event-related desynchronization (ERD) in ß-band frequency during unilateral index finger flexion. Each patient presented at our Department at least on two occasions for tumor resection due to tumor recurrence, and MEG-based motor mapping was performed as part of preoperative assessment before each surgical resection. Whole-brain activation patterns from first to second MEG scan (obtained before first and second surgery) were compared. Additionally, we calculated distances of activation peaks, which represent the location of the primary motor cortex (MC), to determine the magnitude of movement in motor eloquent areas between the first and second MEG scan. We also explored which demographic, anatomic, and pathological factors influence these shifts. Results: The whole-brain activation motor maps showed a subtle movement of the primary MC from first to second timepoint, as was confirmed by the determination of motor activation peaks. The shift of ipsilesional MC was directly correlated with a frontal-parietal tumor location (p < 0.001), presence of motor deficits (p = 0.021), and with a longer period between MEG scans (p = 0.048). Also, a disengagement of wide areas in the contralesional (ipsilateral to finger movement) hemisphere at the second time point was observed. Conclusions: MEG imaging is a sensitive method for depicting the plasticity of the motor cortical network. Although the location of the primary MC undergoes only subtle changes, appreciable shifts can occur in the setting of a stronger and longer impairment of the tumor on the MC. The ipsilateral hemisphere may serve as a reservoir for functional recovery.
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Affiliation(s)
- Lucia Bulubas
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurosurgery and TUM-Neuroimaging Center, Klinikum Rechts der Isar, Technische Universität (TU), Munich, Germany.,Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilians Universität (LMU), Munich, Germany.,International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Munich, Germany
| | - Nina Sardesh
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Tavish Traut
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Anne Findlay
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Danielle Mizuiri
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Susanne M Honma
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Sandro M Krieg
- Department of Neurosurgery and TUM-Neuroimaging Center, Klinikum Rechts der Isar, Technische Universität (TU), Munich, Germany
| | - Mitchel S Berger
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Srikantan S Nagarajan
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
| | - Phiroz E Tarapore
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, United States.,Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, CA, United States
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14
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Liang L, Hu R, Luo X, Feng B, Long W, Song R. Reduced Complexity in Stroke with Motor Deficits: A Resting-State fMRI Study. Neuroscience 2020; 434:35-43. [PMID: 32194224 DOI: 10.1016/j.neuroscience.2020.03.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 01/02/2023]
Abstract
Recently, alterations of complexity due to brain disorders have been demonstrated using brain entropy (BEN), while the changes of brain complexity in stroke, a common cerebrovascular disease, remain unclear. In this research, resting-state functional magnetic resonance imaging (fMRI) was performed to explore the alterations of brain complexity using BEN in twenty stroke patients with motor deficits and nineteen matched healthy controls. The sample entropy (SampEn) was applied to build the BEN mapping for each participant. Compared with healthy controls, stroke patients exhibited lower BEN values in the contralesional precentral gyrus (preCG), bilateral dorsolateral frontal gyrus (SFGdor) and bilateral supplementary motor area (SMA). Moreover, significantly positive correlations between BEN values and Fugl-Meyer Assessment scores were detected in the ipsilesional SFGdor and ipsilesional SMA. Mutual information independence was observed between BEN and regional homogeneity (ReHo), amplitude of low-frequency fluctuations (ALFF), respectively, in the stroke patients. Our findings implied that brain complexity had been impacted after stroke, and also suggested that BEN could be a complementary tool for evaluating the motor impairment after stroke.
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Affiliation(s)
- Liuke Liang
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Rongliang Hu
- Department of Rehabilitation Medicine, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Xuemao Luo
- Department of Radiology, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Bao Feng
- Department of Radiology, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Wansheng Long
- Department of Radiology, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Rong Song
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong Province, School of Biomedical Engineering, Sun Yat-sen University, Guangzhou 510006, China; Shenzhen Research Institute of Sun Yat-sen University, Shenzhen, Guangdong, China.
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15
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Acute Phase Neuronal Activity for the Prognosis of Stroke Recovery. Neural Plast 2019; 2019:1971875. [PMID: 31611914 PMCID: PMC6755296 DOI: 10.1155/2019/1971875] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/17/2019] [Accepted: 06/24/2019] [Indexed: 11/17/2022] Open
Abstract
Strokes causing similar lesions and clinical states can be followed by diverse regains of neurological functions, indicating that the clinical recovery can depend on individual modulating factors. A promising line to disclose these factors, to finally open new therapeutic strategies, is to search for individual indices of recovery prognosis. Here, we pursued on strengthening the value of acute phase electrophysiological biomarkers for poststroke functional recovery in a wide group of patients. We enrolled 120 patients affected by a monohemispheric stroke within the middle cerebral artery territory (70 left and 50 right damages) and collected the NIH stroke scale (NIHSS) score in the acute phase (T0, median 4 days) and chronic follow-up (T1, median 6 months). At T0, we executed electrophysiological noninvasive assessment (19-channel electroencephalography (EEG) or 28 channels per side magnetoencephalography (MEG)) of brain activity at rest by means of band powers in the contra- and ipsilesional hemispheres (CLH, ILH) or the homologous area symmetry (HArS). Low-band (2-6 Hz) HArS entered the regression model for predicting the stabilized clinical state (p < 0.001), with bilateral impairment correlated with a poor outcome. Present data strengthen the fact that low-band impairment of homologous ipsi- and contralesional hemispheric regions in the acute stroke indicate a negative prognosis of clinical recovery.
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16
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Crofts A, Kelly ME, Gibson CL. Imaging Functional Recovery Following Ischemic Stroke: Clinical and Preclinical fMRI Studies. J Neuroimaging 2019; 30:5-14. [PMID: 31608550 PMCID: PMC7003729 DOI: 10.1111/jon.12668] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/12/2019] [Accepted: 09/25/2019] [Indexed: 12/18/2022] Open
Abstract
Disability and effectiveness of physical therapy are highly variable following ischemic stroke due to different brain regions being affected. Functional magnetic resonance imaging (fMRI) studies of patients in the months and years following stroke have given some insight into how the brain recovers lost functions. Initially, new pathways are recruited to compensate for the lost region, showing as a brighter blood oxygen‐level‐dependent (BOLD) signal over a larger area during a task than in healthy controls. Subsequently, activity is reduced to baseline levels as pathways become more efficient, mimicking the process of learning typically seen during development. Preclinical models of ischemic stroke aim to enhance understanding of the biology underlying recovery following stroke. However, the pattern of recruitment and focusing seen in humans has not been observed in preclinical fMRI studies that are highly variable methodologically. Resting‐state fMRI studies show more consistency; however, there are still confounding factors to address. Anesthesia and method of stroke induction are the two main sources of variability in preclinical studies; improvements here can reduce variability and increase the intensity and reproducibility of the BOLD response detected by fMRI. Differences in task or stimulus and differences in analysis method also present a source of variability. This review compares clinical and preclinical fMRI studies of recovery following stroke and focuses on how refinement of preclinical models and MRI methods may obtain more representative fMRI data in relation to human studies.
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Affiliation(s)
- Andrew Crofts
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Michael E Kelly
- Preclinical Imaging Facility, Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Claire L Gibson
- School of Psychology, University of Nottingham, Nottingham, UK
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17
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Abstract
Objective. The aim of this study was to compare the evolution of daily life activities of patients suffering from sequels of strokes who were submitted to hydrotherapy, conventional kinesiotherapy and those with no physiotherapeutic intervention. Method. A total of 152 patients of both genders were selected according to their arrival in the service and were submitted to hydrotherapy in isolation or together with classical kinesiotherapy, over six months. The 45-minute hydrotherapy and classical kinesiotherapy sessions were performed at least three times weekly. Functional activity was evaluated every three months to identify: the dependence, semi-dependence or independence on routine activities. Analysis of the functional activity was assessed by means of the Barthel index. Results. Of the 152 patients, 118 satisfied inclusion criteria. The participants were divided into three groups: 72 (61%) underwent conventional kinesiotherapy, 32 (27.1%) hydrotherapy followed by conventional kinesiotherapy and 14 (11.9%) had no physiotherapeutic interventions. The conventional kinesiotherapy with hydrotherapy group improved in relation to both the degree of independence and lighter motor sequels (p=0.001). The neurological deficit remained greater in the non-treatment group than in the others (p=0.01). Conclusion. The hydrotherapy may be considered a good coadjuvant procedure for patients with sequels due to stroke.
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18
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Zappasodi F, Tecchio F, Marzetti L, Pizzella V, Di Lazzaro V, Assenza G. Longitudinal quantitative electroencephalographic study in mono-hemispheric stroke patients. Neural Regen Res 2019; 14:1237-1246. [PMID: 30804255 PMCID: PMC6425833 DOI: 10.4103/1673-5374.251331] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The identification of individual factors modulating clinical recovery after a stroke is fundamental to personalize the therapeutic intervention to enhance the final clinical outcome. In this framework, electrophysiological factors are promising since are more directly related to neuroplasticity, which supports recovery in stroke patients, than neurovascular factors. In this retrospective observational study, we investigated brain neuronal activity assessed via spectral features and Higuchi’s fractal dimension (HFD) of electroencephalographic signals in acute phase (2–10 days from symptom onset, T0) and sub-acute phase (2.5 months, T1) in 24 patients affected by unilateral middle cerebral artery stroke. Longitudinal assessment of the clinical deficits was performed using the National Institutes of Health Stroke Scale (NIHSS), together with the effective recovery calculated as the ratio between difference of NIHSS at T0 and T1 over the NIHSS value at T0. We observed that delta and alpha band electroencephalographic signal power changed between the two phases in both the hemispheres ipsilateral (ILH) and contralateral (CHL) to the lesion. Moreover, at T0, bilateral higher delta band power correlated with worse clinical conditions (Spearman’s rs = 0.460, P = 0.027 for ILH and rs = 0.508, P = 0.013 for CLH), whereas at T1 this occurred only for delta power in ILH (rs = 0.411, P = 0.046) and not for CHL. Inter-hemispheric difference (ILH vs. CLH) of alpha power in patients was lower at T0 than at T1 (P = 0.020). HFD at T0 was lower than at T1 (P = 0.005), and at both phases, ILH HFD was lower than CLH HFD (P = 0.020). These data suggest that inter-hemispheric low band asymmetry and fractal dimension changes from the acute to the sub-acute phase are sensitive to neuroplasticity processes which subtend clinical recovery. The study protocol was approved by the Bioethical Committee of Ospedale San Giovanni Calibita Fatebenefretelli (No. 40/2011) on July 14, 2011.
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Affiliation(s)
- Filippo Zappasodi
- Department of Neuroscience, Imaging and Clinical Sciences and Institute for Advanced Biomedical Imaging, "G. D'Annunzio" University, Chieti, Italy
| | - Franca Tecchio
- Laboratory of Electrophysiology for Translational NeuroScience (LET'S), ISTC-CNR, and Fondazione Policlinico Gemelli IRCCS, Rome, Italy
| | - Laura Marzetti
- Department of Neuroscience, Imaging and Clinical Sciences and Institute for Advanced Biomedical Imaging, "G. D'Annunzio" University, Chieti, Italy
| | - Vittorio Pizzella
- Department of Neuroscience, Imaging and Clinical Sciences and Institute for Advanced Biomedical Imaging, "G. D'Annunzio" University, Chieti, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Giovanni Assenza
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
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19
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Unilateral, 3D Arm Movement Kinematics Are Encoded in Ipsilateral Human Cortex. J Neurosci 2018; 38:10042-10056. [PMID: 30301759 PMCID: PMC6246886 DOI: 10.1523/jneurosci.0015-18.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 08/02/2018] [Accepted: 09/10/2018] [Indexed: 11/21/2022] Open
Abstract
There is increasing evidence that the hemisphere ipsilateral to a moving limb plays a role in planning and executing movements. However, the exact relationship between cortical activity and ipsilateral limb movements is uncertain. We sought to determine whether 3D arm movement kinematics (speed, velocity, and position) could be decoded from cortical signals recorded from the hemisphere ipsilateral to the moving limb. By having invasively monitored patients perform unilateral reaches with each arm, we also compared the encoding of contralateral and ipsilateral limb kinematics from a single cortical hemisphere. In four motor-intact human patients (three male, one female) implanted with electrocorticography electrodes for localization of their epileptic foci, we decoded 3D movement kinematics of both arms with accuracies above chance. Surprisingly, the spatial and spectral encoding of contralateral and ipsilateral limb kinematics was similar, enabling cross-prediction of kinematics between arms. These results clarify our understanding that the ipsilateral hemisphere robustly contributes to motor execution and supports that the information of complex movements is more bihemispherically represented in humans than has been previously understood.SIGNIFICANCE STATEMENT Although limb movements are traditionally understood to be driven by the cortical hemisphere contralateral to a moving limb, movement-related neural activity has also been found in the ipsilateral hemisphere. This study provides the first demonstration that 3D arm movement kinematics can be decoded from human electrocorticographic signals ipsilateral to the moving limb. Surprisingly, the spatial and spectral encoding of contralateral and ipsilateral limb kinematics was similar. The finding that specific kinematics are encoded in the ipsilateral hemisphere demonstrates that the ipsilateral hemisphere contributes to the execution of unilateral limb movements, improving our understanding of motor control. Additionally, the bihemisheric representation of voluntary movements has implications for the development of neuroprosthetic systems for reaching and for neurorehabilitation strategies following cortical injuries.
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Hari R, Baillet S, Barnes G, Burgess R, Forss N, Gross J, Hämäläinen M, Jensen O, Kakigi R, Mauguière F, Nakasato N, Puce A, Romani GL, Schnitzler A, Taulu S. IFCN-endorsed practical guidelines for clinical magnetoencephalography (MEG). Clin Neurophysiol 2018; 129:1720-1747. [PMID: 29724661 PMCID: PMC6045462 DOI: 10.1016/j.clinph.2018.03.042] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 03/18/2018] [Accepted: 03/24/2018] [Indexed: 12/22/2022]
Abstract
Magnetoencephalography (MEG) records weak magnetic fields outside the human head and thereby provides millisecond-accurate information about neuronal currents supporting human brain function. MEG and electroencephalography (EEG) are closely related complementary methods and should be interpreted together whenever possible. This manuscript covers the basic physical and physiological principles of MEG and discusses the main aspects of state-of-the-art MEG data analysis. We provide guidelines for best practices of patient preparation, stimulus presentation, MEG data collection and analysis, as well as for MEG interpretation in routine clinical examinations. In 2017, about 200 whole-scalp MEG devices were in operation worldwide, many of them located in clinical environments. Yet, the established clinical indications for MEG examinations remain few, mainly restricted to the diagnostics of epilepsy and to preoperative functional evaluation of neurosurgical patients. We are confident that the extensive ongoing basic MEG research indicates potential for the evaluation of neurological and psychiatric syndromes, developmental disorders, and the integrity of cortical brain networks after stroke. Basic and clinical research is, thus, paving way for new clinical applications to be identified by an increasing number of practitioners of MEG.
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Affiliation(s)
- Riitta Hari
- Department of Art, Aalto University, Helsinki, Finland.
| | - Sylvain Baillet
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Gareth Barnes
- Wellcome Centre for Human Neuroimaging, University College of London, London, UK
| | - Richard Burgess
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Nina Forss
- Clinical Neuroscience, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Joachim Gross
- Centre for Cognitive Neuroimaging, University of Glasgow, Glasgow, UK; Institute for Biomagnetism and Biosignalanalysis, University of Muenster, Germany
| | - Matti Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ole Jensen
- Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute of Physiological Sciences, Okazaki, Japan
| | - François Mauguière
- Department of Functional Neurology and Epileptology, Neurological Hospital & University of Lyon, Lyon, France
| | | | - Aina Puce
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Gian-Luca Romani
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. D'Annunzio, Chieti, Italy
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, and Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Samu Taulu
- Institute for Learning & Brain Sciences, University of Washington, Seattle, WA, USA; Department of Physics, University of Washington, Seattle, WA, USA
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21
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Boyd LA, Hayward KS, Ward NS, Stinear CM, Rosso C, Fisher RJ, Carter AR, Leff AP, Copland DA, Carey LM, Cohen LG, Basso DM, Maguire JM, Cramer SC. Biomarkers of Stroke Recovery: Consensus-Based Core Recommendations from the Stroke Recovery and Rehabilitation Roundtable. Neurorehabil Neural Repair 2018; 31:864-876. [PMID: 29233071 DOI: 10.1177/1545968317732680] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The most difficult clinical questions in stroke rehabilitation are "What is this patient's potential for recovery?" and "What is the best rehabilitation strategy for this person, given her/his clinical profile?" Without answers to these questions, clinicians struggle to make decisions regarding the content and focus of therapy, and researchers design studies that inadvertently mix participants who have a high likelihood of responding with those who do not. Developing and implementing biomarkers that distinguish patient subgroups will help address these issues and unravel the factors important to the recovery process. The goal of the present paper is to provide a consensus statement regarding the current state of the evidence for stroke recovery biomarkers. Biomarkers of motor, somatosensory, cognitive and language domains across the recovery timeline post-stroke are considered; with focus on brain structure and function, and exclusion of blood markers and genetics. We provide evidence for biomarkers that are considered ready to be included in clinical trials, as well as others that are promising but not ready and so represent a developmental priority. We conclude with an example that illustrates the utility of biomarkers in recovery and rehabilitation research, demonstrating how the inclusion of a biomarker may enhance future clinical trials. In this way, we propose a way forward for when and where we can include biomarkers to advance the efficacy of the practice of, and research into, rehabilitation and recovery after stroke.
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Affiliation(s)
- Lara A Boyd
- 1 Department of Physical Therapy & the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kathryn S Hayward
- 2 Department of Physical Therapy, University of British Columbia, Vancouver, Canada; Stroke Division, The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia
| | - Nick S Ward
- 3 Sobell Department of Motor Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Cathy M Stinear
- 4 Department of Medicine and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Charlotte Rosso
- 5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, France; AP-HP, Stroke Unit, Pitié-Salpêtrière Hospital, France
| | - Rebecca J Fisher
- 6 Division of Rehabilitation & Ageing, University of Nottingham, Nottingham, UK
| | - Alexandre R Carter
- 7 Department of Neurology, Washington University in Saint Louis, St Louis, MO, USA
| | - Alex P Leff
- 8 Department of Brain Repair and Rehabilitation, Institute of Neurology & Institute of Cognitive Neuroscience, University College London, Queens Square, London, UK
| | - David A Copland
- 9 School of Health & Rehabilitation Sciences, University of Queensland, Brisbane, Australia; and University of Queensland Centre for Clinical Research, Brisbane, Australia
| | - Leeanne M Carey
- 10 School of Allied Health, College of Science, Health and Engineering, La Trobe, University, Bundoora, Australia; and Neurorehabilitation and Recovery, Stroke Division, The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia
| | - Leonardo G Cohen
- 11 Human Cortical Physiology and Neurorehabilitation Section, NINDS, NIH, Bethesda, MD, USA
| | - D Michele Basso
- 12 School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH, USA
| | - Jane M Maguire
- 13 Faculty of Health, University of Technology Sydney, Ultimo, Sydney, Australia
| | - Steven C Cramer
- 14 University of California, Irvine, CA, USA; Depts. Neurology, Anatomy & Neurobiology, and Physical Medicine & Rehabilitation, Irvine, CA, USA
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22
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Boyd LA, Hayward KS, Ward NS, Stinear CM, Rosso C, Fisher RJ, Carter AR, Leff AP, Copland DA, Carey LM, Cohen LG, Basso DM, Maguire JM, Cramer SC. Biomarkers of stroke recovery: Consensus-based core recommendations from the Stroke Recovery and Rehabilitation Roundtable. Int J Stroke 2018; 12:480-493. [PMID: 28697711 DOI: 10.1177/1747493017714176] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The most difficult clinical questions in stroke rehabilitation are "What is this patient's potential for recovery?" and "What is the best rehabilitation strategy for this person, given her/his clinical profile?" Without answers to these questions, clinicians struggle to make decisions regarding the content and focus of therapy, and researchers design studies that inadvertently mix participants who have a high likelihood of responding with those who do not. Developing and implementing biomarkers that distinguish patient subgroups will help address these issues and unravel the factors important to the recovery process. The goal of the present paper is to provide a consensus statement regarding the current state of the evidence for stroke recovery biomarkers. Biomarkers of motor, somatosensory, cognitive and language domains across the recovery timeline post-stroke are considered; with focus on brain structure and function, and exclusion of blood markers and genetics. We provide evidence for biomarkers that are considered ready to be included in clinical trials, as well as others that are promising but not ready and so represent a developmental priority. We conclude with an example that illustrates the utility of biomarkers in recovery and rehabilitation research, demonstrating how the inclusion of a biomarker may enhance future clinical trials. In this way, we propose a way forward for when and where we can include biomarkers to advance the efficacy of the practice of, and research into, rehabilitation and recovery after stroke.
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Affiliation(s)
- Lara A Boyd
- 1 Department of Physical Therapy & the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kathryn S Hayward
- 2 Department of Physical Therapy, University of British Columbia, Vancouver, Canada; Stroke Division, The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia
| | - Nick S Ward
- 3 Sobell Department of Motor Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Cathy M Stinear
- 4 Department of Medicine and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Charlotte Rosso
- 5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France.,6 AP-HP, Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France
| | - Rebecca J Fisher
- 7 Division of Rehabilitation & Ageing, University of Nottingham, Nottingham, UK
| | - Alexandre R Carter
- 8 Department of Neurology, Washington University in Saint Louis, St Louis, MO, USA
| | - Alex P Leff
- 9 Department of Brain Repair and Rehabilitation, Institute of Neurology & Institute of Cognitive Neuroscience, University College London, Queens Square, London, UK
| | - David A Copland
- 10 School of Health & Rehabilitation Sciences, University of Queensland, Brisbane, Australia; and University of Queensland Centre for Clinical Research, Brisbane, Australia
| | - Leeanne M Carey
- 11 School of Allied Health, College of Science, Health and Engineering, La Trobe, University, Bundoora, Australia; and Neurorehabilitation and Recovery, Stroke Division, The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia
| | - Leonardo G Cohen
- 12 Human Cortical Physiology and Neurorehabilitation Section, NINDS, NIH, Bethesda, MD, USA
| | - D Michele Basso
- 13 School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH, USA
| | - Jane M Maguire
- 14 Faculty of Health, University of Technology, Ultimo, Sydney, Australia
| | - Steven C Cramer
- 15 University of California, Irvine, CA, USA; Depts. Neurology, Anatomy & Neurobiology, and Physical Medicine & Rehabilitation, Irvine, CA, USA
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Rhodes E, Gaetz WC, Marsden J, Hall SD. Transient Alpha and Beta Synchrony Underlies Preparatory Recruitment of Directional Motor Networks. J Cogn Neurosci 2018; 30:867-875. [PMID: 29488848 DOI: 10.1162/jocn_a_01250] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Modulations in motor cortical beta and alpha activity have been implicated in the preparation, execution, and termination of voluntary movements. The functional role of motor cortex beta activity is yet to be defined, though two opposing theories prevail. The idling cortex theory suggests that large-scale motor networks, in the absence of input, revert to an intrinsic oscillatory state. The alternative theory proposes that beta activity promotes postural tone at the expense of voluntary movement. These theories are primarily based on observations of event-related desynchronization associated with movement onset. Here, we explore the changes in alpha and beta oscillatory activity associated with the specific behavioral patterns during an established directional uncertainty paradigm. We demonstrate that, consistent with current proposals, alpha and beta desynchronization reflects a process of disengagement from existing networks to enable the creation of functional assemblies. We demonstrate that, following desynchronization, a novel signature of transient alpha synchrony underlies the recruitment of functional assemblies required for directional control. Although alpha and beta desynchronization are dependent upon the number of cues presented, they are not predictive of movement preparation. However, the transient alpha synchrony occurs only when participants have sufficient information to prepare for movement and shows a direct relationship with behavioral performance measures.
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24
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Porcaro C, Cottone C, Cancelli A, Salustri C, Tecchio F. Functional Semi-Blind Source Separation Identifies Primary Motor Area Without Active Motor Execution. Int J Neural Syst 2018; 28:1750047. [DOI: 10.1142/s0129065717500472] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
High time resolution techniques are crucial for investigating the brain in action. Here, we propose a method to identify a section of the upper-limb motor area representation (FS_M1) by means of electroencephalographic (EEG) signals recorded during a completely passive condition (FS_M1bySS). We delivered a galvanic stimulation to the median nerve and we applied to EEG the semi-Blind Source Separation (s-BSS) algorithm named Functional Source Separation (FSS). In order to prove that FS_M1bySS is part of FS_M1, we also collected EEG in a motor condition, i.e. during a voluntary movement task (isometric handgrip) and in a rest condition, i.e. at rest with eyes open and closed. In motor condition, we show that the cortico-muscular coherence (CMC) of FS_M1bySS does not differ from FS_ M1 CMC (0.04 for both sources). Moreover, we show that the FS_M1bySS’s ongoing whole band activity during Motor and both rest conditions displays high mutual information and time correlation with FS_M1 (above 0.900 and 0.800, respectively) whereas much smaller ones with the primary somatosensory cortex [Formula: see text] (about 0.300 and 0.500, [Formula: see text]). FS_M1bySS as a marker of the upper-limb FS_M1 representation obtainable without the execution of an active motor task is a great achievement of the FSS algorithm, relevant in most experimental, neurological and psychiatric protocols.
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Affiliation(s)
- Camillo Porcaro
- LET’S - ISTC - CNR, Rome 00185, Italy
- Movement Control and Neuroplasticity Research Group, Department of Kinesiology, KU Leuven, Leuven 3001, Belgium
- Birmingham University Imaging Centre (BUIC), School of Psychology, University of Birmingham, Birmingham B15 2TT, UK
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
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25
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Disentangling Somatosensory Evoked Potentials of the Fingers: Limitations and Clinical Potential. Brain Topogr 2018; 31:498-512. [PMID: 29353446 PMCID: PMC5889784 DOI: 10.1007/s10548-017-0617-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 12/30/2017] [Indexed: 12/21/2022]
Abstract
In searching for clinical biomarkers of the somatosensory function, we studied reproducibility of somatosensory potentials (SEP) evoked by finger stimulation in healthy subjects. SEPs induced by electrical stimulation and especially after median nerve stimulation is a method widely used in the literature. It is unclear, however, if the EEG recordings after finger stimulation are reproducible within the same subject. We tested in five healthy subjects the consistency and reproducibility of responses through bootstrapping as well as test–retest recordings. We further evaluated the possibility to discriminate activity of different fingers both at electrode and at source level. The lack of consistency and reproducibility suggest responses to finger stimulation to be unreliable, even with reasonably high signal-to-noise ratio and adequate number of trials. At sources level, somatotopic arrangement of the fingers representation was only found in one of the subjects. Although finding distinct locations of the different fingers activation was possible, our protocol did not allow for non-overlapping dipole representations of the fingers. We conclude that despite its theoretical advantages, we cannot recommend the use of somatosensory potentials evoked by finger stimulation to extract clinical biomarkers.
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26
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Mogilner AY. Neuromodulation and Neuronal Plasticity. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00009-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Merkel C, Hausmann J, Hopf JM, Heinze HJ, Buentjen L, Schoenfeld MA. Active prosthesis dependent functional cortical reorganization following stroke. Sci Rep 2017; 7:8680. [PMID: 28819123 PMCID: PMC5561114 DOI: 10.1038/s41598-017-09325-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 07/20/2017] [Indexed: 11/23/2022] Open
Abstract
The present study investigated the neural correlates associated with gait improvements triggered by an active prosthesis in patients with drop-foot following stroke during the chronic stage. Eleven patients took part in the study. MEG recordings in conjunction with somatosensory stimulation of the left and right hand as well as gait analyses were performed shortly before or after prosthesis implantation surgery and 3–4 months later. Plastic changes of the sensorimotor cortex of the ipsi- and contralesional hemisphere were revealed. Gait analysis indicated that all patients improved their gait with the active prosthesis. Patients with larger plastic changes within the lesioned hemisphere maintained their improved gait performance even when the prosthesis was turned off. Patients with larger contralesional changes also improved their gait with the active prosthesis. However, their gait measures decreased when the prosthesis was turned off. The current data provide the neural basis of gait improvement triggered by an active prosthesis and has important implications with respect to the choice of the type of active prosthesis (implantable vs removable) and to the selection procedure of the patients (length of testing period).
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Affiliation(s)
- Christian Merkel
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.
| | - Janet Hausmann
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
| | - Jens-Max Hopf
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.,Department of Behavioral Neurology, Leibniz-Institute for Neurobiology, Magdeburg, Germany
| | - Hans-Jochen Heinze
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.,Department of Stereotactic Neurosurgery, Otto-von-Guericke University, Magdeburg, Germany.,Department of Behavioral Neurology, Leibniz-Institute for Neurobiology, Magdeburg, Germany
| | - Lars Buentjen
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.,Department of Stereotactic Neurosurgery, Otto-von-Guericke University, Magdeburg, Germany
| | - Mircea Ariel Schoenfeld
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.,Department of Behavioral Neurology, Leibniz-Institute for Neurobiology, Magdeburg, Germany.,Kliniken Schmieder Heidelberg, Heidelberg, Germany
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28
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Bundy DT, Souders L, Baranyai K, Leonard L, Schalk G, Coker R, Moran DW, Huskey T, Leuthardt EC. Contralesional Brain-Computer Interface Control of a Powered Exoskeleton for Motor Recovery in Chronic Stroke Survivors. Stroke 2017; 48:1908-1915. [PMID: 28550098 PMCID: PMC5482564 DOI: 10.1161/strokeaha.116.016304] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 03/22/2017] [Accepted: 04/18/2017] [Indexed: 12/27/2022]
Abstract
Supplemental Digital Content is available in the text. Background and Purpose— There are few effective therapies to achieve functional recovery from motor-related disabilities affecting the upper limb after stroke. This feasibility study tested whether a powered exoskeleton driven by a brain–computer interface (BCI), using neural activity from the unaffected cortical hemisphere, could affect motor recovery in chronic hemiparetic stroke survivors. This novel system was designed and configured for a home-based setting to test the feasibility of BCI-driven neurorehabilitation in outpatient environments. Methods— Ten chronic hemiparetic stroke survivors with moderate-to-severe upper-limb motor impairment (mean Action Research Arm Test=13.4) used a powered exoskeleton that opened and closed the affected hand using spectral power from electroencephalographic signals from the unaffected hemisphere associated with imagined hand movements of the paretic limb. Patients used the system at home for 12 weeks. Motor function was evaluated before, during, and after the treatment. Results— Across patients, our BCI-driven approach resulted in a statistically significant average increase of 6.2 points in the Action Research Arm Test. This behavioral improvement significantly correlated with improvements in BCI control. Secondary outcomes of grasp strength, Motricity Index, and the Canadian Occupational Performance Measure also significantly improved. Conclusions— The findings demonstrate the therapeutic potential of a BCI-driven neurorehabilitation approach using the unaffected hemisphere in this uncontrolled sample of chronic stroke survivors. They also demonstrate that BCI-driven neurorehabilitation can be effectively delivered in the home environment, thus increasing the probability of future clinical translation. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT02552368.
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Affiliation(s)
- David T Bundy
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Lauren Souders
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Kelly Baranyai
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Laura Leonard
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Gerwin Schalk
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Robert Coker
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Daniel W Moran
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Thy Huskey
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.)
| | - Eric C Leuthardt
- From the Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City (D.T.B.); Departments of Biomedical Engineering (D.T.B., R.C., D.W.M., E.C.L.), Neurology (L.S., K.B., L.L., T.H.), Neurological Surgery (E.C.L.), Mechanical Engineering and Material Sciences (E.C.L.), and Neuroscience (E.C.L.), Washington University, St. Louis, MO; and National Center for Adaptive Neurotechnologies, Wadsworth Center, NYS Department of Health, Albany, NY (G.S.).
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29
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Yu GH, Lee JS, Kim SK, Cha TH. Effects of interactive metronome training on upper extremity function, ADL and QOL in stroke patients. NeuroRehabilitation 2017; 41:161-168. [PMID: 28527229 DOI: 10.3233/nre-171468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Rhythm and timing training is stimulation that substitutes for a damaged function controls muscular movement or temporal element, which has positive impacts on the neurological aspect and movement of the brain. OBJECTIVE This study is to assess the changes caused by rhythm and timing training using an interactive metronome (IM) on upper extremity function, ADL and QOL in stroke patients. METHODS In order to assess the effects of IM training, a group experiment was conducted on 30 stroke patients. Twelve sessions of IM training were provided for the experimental group three times a week for four weeks, while the control group was trained with a Bilateral arm Self-Exercise (BSE) for the same period. Both groups were evaluated by pre- and post-tests through MFT, MAL, K-MBI and SS-QOL. RESULT There were more statistically significant differences (<0.05) in the total score of MFT and the finger control item in the IM Group than in the BSE Group. With respect to ADL, there were more statistically significant differences (<0.05) in the total score of K-MBI and the dressing item in the IM Group than in the BSE Group. CONCLUSION The study proposes that IM training can be applied as an occupational therapy program in patients with various diseases who need to adjust the time for performing movements as well as stroke patients.
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Affiliation(s)
- Ga-Hui Yu
- Department of Occupational Therapy, Yusung Wellness Rehabilitation Hospital, Daejeon, Republic of Korea
| | - Jae-Shin Lee
- Department of Occupational Therapy, Konyang University, Daejeon, Republic of Korea
| | - Su-Kyoung Kim
- Department of Occupational Therapy, Konyang University, Daejeon, Republic of Korea
| | - Tae-Hyun Cha
- Department of Occupational Therapy, Konyang University, Daejeon, Republic of Korea
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30
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Kober SE, Schweiger D, Reichert JL, Neuper C, Wood G. Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects. Appl Psychophysiol Biofeedback 2017; 42:69-83. [PMID: 28197747 PMCID: PMC5344963 DOI: 10.1007/s10484-017-9353-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In the present study, we investigated the effects of upper alpha based neurofeedback (NF) training on electrical brain activity and cognitive functions in stroke survivors. Therefore, two single chronic stroke patients with memory deficits (subject A with a bilateral subarachnoid hemorrhage; subject B with an ischemic stroke in the left arteria cerebri media) and a healthy elderly control group (N = 24) received up to ten NF training sessions. To evaluate NF training effects, all participants performed multichannel electroencephalogram (EEG) resting measurements and a neuropsychological test battery assessing different cognitive functions before and after NF training. Stroke patients showed improvements in memory functions after successful NF training compared to the pre-assessment. Subject B had a pathological delta (0.5-4 Hz) and upper alpha (10-12 Hz) power maximum over the unaffected hemisphere before NF training. After NF training, he showed a more bilateral and "normalized" topographical distribution of these EEG frequencies. Healthy participants as well as subject A did not show any abnormalities in EEG topography before the start of NF training. Consequently, no changes in the topographical distribution of EEG activity were observed in these participants when comparing the pre- and post-assessment. Hence, our results show that upper alpha based NF training had on the one hand positive effects on memory functions, and on the other hand led to cortical "normalization" in a stroke patient with pathological brain activation patterns, which underlines the potential usefulness of NF as neurological rehabilitation tool.
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Affiliation(s)
- Silvia Erika Kober
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, Graz, 8010 Austria
| | - Daniela Schweiger
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
| | | | - Christa Neuper
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, Graz, 8010 Austria
- Institute of Neural Engineering, Laboratory of Brain-Computer Interfaces, Graz University of Technology, Stremayrgasse 16, Graz, 8010 Austria
| | - Guilherme Wood
- Department of Psychology, University of Graz, Universitaetsplatz 2/III, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, Graz, 8010 Austria
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31
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Neurovascular unit remodelling in the subacute stage of stroke recovery. Neuroimage 2017; 146:869-882. [DOI: 10.1016/j.neuroimage.2016.09.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 01/19/2023] Open
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32
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Localized N20 Component of Somatosensory Evoked Magnetic Fields in Frontoparietal Brain Tumor Patients Using Noise-Normalized Approaches. Clin Neuroradiol 2017; 28:267-281. [PMID: 28116447 DOI: 10.1007/s00062-017-0557-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE To localize sensorimotor cortical activation in 10 patients with frontoparietal tumors using quantitative magnetoencephalography (MEG) with noise-normalized approaches. MATERIAL AND METHODS Somatosensory evoked magnetic fields (SEFs) were elicited in 10 patients with somatosensory tumors and in 10 control participants using electrical stimulation of the median nerve via the right and left wrists. We localized the N20m component of the SEFs using dynamic statistical parametric mapping (dSPM) and standardized low-resolution brain electromagnetic tomography (sLORETA) combined with 3D magnetic resonance imaging (MRI). The obtained coordinates were compared between groups. Finally, we statistically evaluated the N20m parameters across hemispheres using non-parametric statistical tests. RESULTS The N20m sources were accurately localized to Brodmann area 3b in all members of the control group and in seven of the patients; however, the sources were shifted in three patients relative to locations outside the primary somatosensory cortex (SI). Compared with the affected (tumor) hemispheres in the patient group, N20m amplitudes and the strengths of the current sources were significantly lower in the unaffected hemispheres and in both hemispheres of the control group. These results were consistent for both dSPM and sLORETA approaches. CONCLUSION Tumors in the sensorimotor cortex lead to cortical functional reorganization and an increase in N20m amplitude and current-source strengths. Noise-normalized approaches for MEG analysis that are integrated with MRI show accurate and reliable localization of sensorimotor function.
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Formaggio E, Masiero S, Bosco A, Izzi F, Piccione F, Del Felice A. Quantitative EEG Evaluation During Robot-Assisted Foot Movement. IEEE Trans Neural Syst Rehabil Eng 2016; 25:1633-1640. [PMID: 27845668 DOI: 10.1109/tnsre.2016.2627058] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Passiveand imagined limbmovements induce changes in cerebral oscillatory activity. Central modulatory effects play a role in plastic changes, and are of uttermost importance in rehabilitation. This has extensively been studied for upper limb, but less is known for lower limb. The aim of this study is to investigate the topographical distribution of event-related desynchronization/synchronization(ERD/ERS) and task-relatedcoherence during a robot-assisted and a motor imagery task of lower limb in healthy subjects to inform rehabilitation paradigms. 32-channels electroencephalogram (EEG) was recorded in twenty-one healthy right footed and handed subjects during a robot-assisted single-joint cyclic right ankle movement performed by the BTS ANYMOV robotic hospital bed. Data were acquired with a block protocol for passive and imagined movement at a frequency of 0.2 Hz. ERD/ERS and task related coherence were calculated in alpha1 (8-10 Hz), alpha2 (10.5-12.5 Hz) and beta (13-30 Hz) frequency ranges. During passive movement, alpha2 rhythm desynchronized overC3 and ipsilateral frontal areas (F4, FC2, FC6); betaERD was detected over the bilateral motor areas (Cz, C3, C4). During motor imagery, a significant desynchronization was evident for alpha1 over contralateral sensorimotor cortex (C3), for alpha2 over bilateral motor areas (C3 and C4), and for beta over central scalp areas. Task-related coherence decreased during passive movement in alpha2 band between contralateral central area (C3, CP5, CP1, P3) and ipsilateral frontal area (F8, FC6, T8); beta band coherence decreased between C3-C4 electrodes, and increased between C3-Cz. These data contribute to the understanding of oscillatory activity and functional neuronal interactions during lower limb robot-assisted motor performance. The final output of this line of research is to inform the design and development of neurorehabilitation protocols.
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Caliandro P, Vecchio F, Miraglia F, Reale G, Della Marca G, La Torre G, Lacidogna G, Iacovelli C, Padua L, Bramanti P, Rossini PM. Small-World Characteristics of Cortical Connectivity Changes in Acute Stroke. Neurorehabil Neural Repair 2016; 31:81-94. [PMID: 27511048 DOI: 10.1177/1545968316662525] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. Recently, complexity of brain connectivity has been described using graph theory, a mathematical approach that depicts important properties of complex systems by quantifying topologies of network representations. Functional and dynamic changes of brain connectivity can be reliably analyzed via electroencephalography (EEG) recordings even when they are not yet reflected in structural changes of connections. Objective We tested whether and how ischemic stroke in the acute stage may determine changes in small-worldness of cortical networks as measured by cortical sources of EEG. Methods Graph characteristics of EEG of 30 consecutive stroke patients in acute stage (no more than 5 days after the event) were examined. Connectivity analysis was performed using eLORETA in both hemispheres. Results Network rearrangements were mainly detected in delta, theta, and alpha bands when patients were compared with healthy subjects. In delta and alpha bands similar findings were observed in both hemispheres regardless of the side of ischemic lesion: bilaterally decreased small-worldness in the delta band and bilaterally increased small-worldness in the alpha2 band. In the theta band, bilaterally decreased small-worldness was observed only in patients with stroke in the left hemisphere. Conclusions After an acute stroke, brain cortex rearranges its network connections diffusely, in a frequency-dependent modality probably in order to face the new anatomical and functional frame.
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Affiliation(s)
- Pietro Caliandro
- Catholic University, Rome, Italy .,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
| | | | | | | | | | | | | | - Chiara Iacovelli
- Catholic University, Rome, Italy.,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
| | - Luca Padua
- Catholic University, Rome, Italy.,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
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Marini A, Galetto V, Tatu K, Duca S, Geminiani G, Sacco K, Zettin M. Recovering two languages with the right hemisphere. BRAIN AND LANGUAGE 2016; 159:35-44. [PMID: 27289209 DOI: 10.1016/j.bandl.2016.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 02/26/2016] [Accepted: 05/28/2016] [Indexed: 06/06/2023]
Abstract
Converging evidence suggests that the right hemisphere (RH) plays an important role in language recovery from aphasia after a left hemisphere (LH) lesion. In this longitudinal study we describe the neurological, cognitive, and linguistic profile of A.C., a bilingual who, after a severe traumatic brain injury, developed a form of fluent aphasia that affected his two languages (i.e., Romanian and Italian). The trauma-induced parenchymal atrophy led to an exceptional ventricular dilation that, gradually, affected the whole left hemisphere. A.C. is now recovering both languages relying only on his right hemisphere. An fMRI experiment employing a bilingual covert verb generation task documented the involvement of the right middle temporal gyrus in processes of lexical selection and access. This case supports the hypothesis that the RH plays a role in language recovery from aphasia when the LH has suffered massive lesions.
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Affiliation(s)
- Andrea Marini
- Dipartimento di Lingue e Letterature, Comunicazione, Formazione e Società, University of Udine, Udine, Italy; Scientific Institute, IRCCS Eugenio Medea, San Vito al Tagliamento, Pordenone, Italy; Claudiana - Landesfachhochschule für Gesundheitsberufe, Bolzano, Italy.
| | - Valentina Galetto
- Centro Puzzle, Torino, Italy; Center for Cognitive Science, Università degli Studi di Torino, Italy
| | - Karina Tatu
- Dipartimento di Psicologia, Università di Torino, Italy; Koelliker Hospital, Turin, Italy
| | | | - Giuliano Geminiani
- Center for Cognitive Science, Università degli Studi di Torino, Italy; Dipartimento di Psicologia, Università di Torino, Italy; Koelliker Hospital, Turin, Italy; Neuroscience Institute of Turin, Italy
| | - Katiuscia Sacco
- Center for Cognitive Science, Università degli Studi di Torino, Italy; Dipartimento di Psicologia, Università di Torino, Italy; Koelliker Hospital, Turin, Italy; Neuroscience Institute of Turin, Italy
| | - Marina Zettin
- Centro Puzzle, Torino, Italy; Center for Cognitive Science, Università degli Studi di Torino, Italy; Dipartimento di Psicologia, Università di Torino, Italy.
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Carey LM, Seitz RJ. Functional Neuroimaging in Stroke Recovery and Neurorehabilitation: Conceptual Issues and Perspectives. Int J Stroke 2016; 2:245-64. [DOI: 10.1111/j.1747-4949.2007.00164.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background In stroke, functional neuroimaging has become a potent diagnostic tool; opened new insights into the pathophysiology of ischaemic damage in the human brain; and made possible the assessment of functional–structural relationships in postlesion recovery. Summary of review Here, we give a critical account on the potential and limitation of functional neuroimaging and discuss concepts related to the use of neuroimaging for exploring the neurobiological and neuroanatomical mechanisms of poststroke recovery and neurorehabilitation. We identify and provide evidence for five hypotheses that functional neuroimaging can provide new insights into: adaptation occurs at the level of functional brain systems; the brain–behaviour relationship varies with recovery and over time; functional neuroimaging can improve our ability to predict recovery and select individuals for rehabilitation; mechanisms of recovery reflect different pathophysiological phases; and brain adaptation may be modulated by experience and specific rehabilitation. The significance and application of this new evidence is discussed, and recommendations made for investigations in the field. Conclusion Functional neuroimaging is an important tool to explore the mechanisms underlying brain plasticity and, thereby, to guide clinical research in neurorehabilitation.
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Affiliation(s)
- Leeanne M. Carey
- National Stroke Research Institute, Neurosciences Building, Heidelberg Heights, Vic., Australia
- School of Occupational Therapy, LaTrobe University, Bundoora, Vic., Australia
| | - Rüdiger J. Seitz
- National Stroke Research Institute, Neurosciences Building, Heidelberg Heights, Vic., Australia
- Institute of Advanced Study, La Trobe University, Bundoora, Vic., Australia
- Department of Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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Ramshur JT, de Jongh Curry AL, Waters RS. Wireless simultaneous stimulation-and-recording device to train cortical circuits in somatosensory cortex. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2014:426-9. [PMID: 25569987 DOI: 10.1109/embc.2014.6943619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We describe for the first time the design, implementation, and testing of a telemetry controlled simultaneous stimulation and recording device (SRD) to deliver chronic intercortical microstimulation (ICMS) to physiologically identified sites in rat somatosensory cortex (SI) and test hypotheses that chronic ICMS strengthens interhemispheric pathways and leads to functional reorganization in the enhanced cortex. The SRD is a custom embedded device that uses the Cypress Semiconductor's programmable system on a chip (PSoC) that is remotely controlled via Bluetooth. The SRC can record single or multiunit responses from any two of 12 available inputs at 1-15 ksps per channel and simultaneously deliver stimulus pulses (0-255 μA; 10 V compliance) to two user selectable electrodes using monophasic, biphasic, or pseudophasic stimulation waveforms (duration: 0-5 ms, inter-phase interval: 0-5 ms, frequency: 0.1-5 s, delay: 0-10 ms). The SRD was bench tested and validated in vivo in a rat animal model.
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Miltner WHR, Bauder H, Taub E. Change in Movement-Related Cortical Potentials Following Constraint-Induced Movement Therapy (CIMT) After Stroke. ZEITSCHRIFT FUR PSYCHOLOGIE-JOURNAL OF PSYCHOLOGY 2016. [DOI: 10.1027/2151-2604/a000245] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Abstract. Patients with chronic stroke were given Constraint-Induced Movement Therapy (CIMT) over an intensive two-week course of treatment. The intervention resulted in a large improvement in use of the more-affected upper extremity in the laboratory and in the real-world environment. High-resolution electroencephalography (EEG) showed that the treatment produced marked changes in cortical activity that correlated with the significant rehabilitative effects. Repetitive unilateral self-paced voluntary movements showed a large increase after treatment in the amplitudes of the late components of the Bereitschaftspotential (BP) both in the hemisphere contralateral to the more-affected arm and in the ipsilateral hemisphere. Simultaneous electromyographic recordings (EMG) and other aspects of the data indicate that the emergence of the movement-related neural source in the healthy hemisphere was not due to mirror movements of the non-test hand and that the increase in BP amplitudes was not the result of an increase in the force or effort of the response pre- to post-treatment. The results are consistent with the rehabilitation treatment having produced a use-dependent cortical reorganization and is a case where the physiological data interdigitates with and provides additional credibility to the clinical data.
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Affiliation(s)
- Wolfgang H. R. Miltner
- Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany
| | - Heike Bauder
- Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany
| | - Edward Taub
- Department of Psychology, University of Alabama at Birmingham, AL, USA
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Antelis JM, Montesano L, Ramos-Murguialday A, Birbaumer N, Minguez J. Decoding Upper Limb Movement Attempt From EEG Measurements of the Contralesional Motor Cortex in Chronic Stroke Patients. IEEE Trans Biomed Eng 2016; 64:99-111. [PMID: 27046866 DOI: 10.1109/tbme.2016.2541084] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
GOAL Stroke survivors usually require motor rehabilitation therapy as, due to the lesion, they completely or partially loss mobility in the limbs. Brain-computer interface technology offers the possibility of decoding the attempt to move paretic limbs in real time to improve existing motor rehabilitation. However, a major difficulty for the practical application of the BCI to stroke survivors is that the brain rhythms that encode the motor states might be diminished due to the lesion. This study investigates the continuous decoding of natural attempt to move the paralyzed upper limb in stroke survivors from electroencephalographic signals of the unaffected contralesional motor cortex. RESULTS Experiments were carried out with the aid of six severely affected chronic stroke patients performing/attempting self-selected reaching movements of the unaffected/affected upper limb. The electroencephalographic (EEG) analysis showed significant cortical activation on the uninjured motor cortex when moving the contralateral unaffected arm and in the attempt to move the ipsilateral affected arm. Using this activity, significant continuous decoding of movement was obtained in six out of six participants in movements of the unaffected limb, and in four out of six participants in the attempt to move the affected limb. CONCLUSION This study showed that it is possible to construct a decoder of the attempt to move the paretic arm for chronic stroke patients using the EEG activity of the healthy contralesional motor cortex. SIGNIFICANCE This decoding model could provide to stroke survivors with a natural, easy, and intuitive way to achieve control of BCIs or robot-assisted rehabilitation devices.
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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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Foldes ST, Weber DJ, Collinger JL. MEG-based neurofeedback for hand rehabilitation. J Neuroeng Rehabil 2015; 12:85. [PMID: 26392353 PMCID: PMC4578759 DOI: 10.1186/s12984-015-0076-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Providing neurofeedback (NF) of motor-related brain activity in a biologically-relevant and intuitive way could maximize the utility of a brain-computer interface (BCI) for promoting therapeutic plasticity. We present a BCI capable of providing intuitive and direct control of a video-based grasp. METHODS Utilizing magnetoencephalography's (MEG) high temporal and spatial resolution, we recorded sensorimotor rhythms (SMR) that were modulated by grasp or rest intentions. SMR modulation controlled the grasp aperture of a stop motion video of a human hand. The displayed hand grasp position was driven incrementally towards a closed or opened state and subjects were required to hold the targeted position for a time that was adjusted to change the task difficulty. RESULTS We demonstrated that three individuals with complete hand paralysis due to spinal cord injury (SCI) were able to maintain brain-control of closing and opening a virtual hand with an average of 63 % success which was significantly above the average chance rate of 19 %. This level of performance was achieved without pre-training and less than 4 min of calibration. In addition, successful grasp targets were reached in 1.96 ± 0.15 s. Subjects performed 200 brain-controlled trials in approximately 30 min excluding breaks. Two of the three participants showed a significant improvement in SMR indicating that they had learned to change their brain activity within a single session of NF. CONCLUSIONS This study demonstrated the utility of a MEG-based BCI system to provide realistic, efficient, and focused NF to individuals with paralysis with the goal of using NF to induce neuroplasticity.
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Affiliation(s)
- Stephen T Foldes
- VA Pittsburgh Healthcare System, Human Engineering Research Laboratories, Pittsburgh, PA, 15206, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Douglas J Weber
- VA Pittsburgh Healthcare System, Human Engineering Research Laboratories, Pittsburgh, PA, 15206, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Department of Bioengineering, University of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Jennifer L Collinger
- VA Pittsburgh Healthcare System, Human Engineering Research Laboratories, Pittsburgh, PA, 15206, USA.
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Center for the Neural Basis of Cognition, Carnegie Mellon University, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Department of Bioengineering, University of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
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Evidence for a role of the reticulospinal system in recovery of skilled reaching after cortical stroke: initial results from a model of ischemic cortical injury. Exp Brain Res 2015; 233:3231-51. [PMID: 26231990 DOI: 10.1007/s00221-015-4390-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 07/13/2015] [Indexed: 12/25/2022]
Abstract
The purposes of this pilot study were to create a model of focal cortical ischemia in Macaca fascicularis and to explore contributions of the reticulospinal system in recovery of reaching. Endothelin-1 was used to create a focal lesion in the shoulder/elbow representation of left primary motor cortex (M1) of two adult female macaques. Repetitive microstimulation was used to map upper limb motor outputs from right and left cortical motor areas and from the pontomedullary reticular formation (PMRF). In subject 1 with a small lesion and spontaneous recovery, reaching was mildly impaired. Changes were evident in the shoulder/elbow representations of both the lesioned and contralesional M1, and there appeared to be fewer than expected upper limb responses from the left (ipsilesional) PMRF. In subject 2 with a substantial lesion, reaching was severely impaired immediately after the lesion. After 12 weeks of intensive rehabilitative training, reach performance recovered to near-baseline levels, but movement times remained about 50% slower. Surprisingly, the shoulder/elbow representation in the lesioned M1 remained completely absent after recovery, and there was a little change in the contralesional M1. There was a definite difference in motor output patterns for left versus right PMRF for this subject, with an increase in right arm responses from right PMRF and a paucity of left arm responses from left PMRF. The results are consistent with increased reliance on PMRF motor outputs for recovery of voluntary upper limb motor control after significant cortical ischemic injury.
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Bannister LC, Crewther SG, Gavrilescu M, Carey LM. Improvement in Touch Sensation after Stroke is Associated with Resting Functional Connectivity Changes. Front Neurol 2015; 6:165. [PMID: 26284024 PMCID: PMC4521505 DOI: 10.3389/fneur.2015.00165] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 07/07/2015] [Indexed: 12/24/2022] Open
Abstract
Background Distributed brain networks are known to be involved in facilitating behavioral improvement after stroke, yet few, if any, studies have investigated the relationship between improved touch sensation after stroke and changes in functional brain connectivity. Objective We aimed to identify how recovery of somatosensory function in the first 6 months after stroke was associated with functional network changes as measured using resting-state connectivity analysis of functional magnetic resonance imaging (fMRI) data. Methods Ten stroke survivors underwent clinical testing and resting-state fMRI scans at 1 and 6 months post-stroke. Ten age-matched healthy participants were included as controls. Results Patients demonstrated a wide range of severity of touch impairment 1 month post-stroke, followed by variable improvement over time. In the stroke group, significantly stronger interhemispheric functional correlations between regions of the somatosensory system, and with visual and frontal areas, were found at 6 months than at 1 month post-stroke. Clinical improvement in touch discrimination was associated with stronger correlations at 6 months between contralesional secondary somatosensory cortex (SII) and inferior parietal cortex and middle temporal gyrus, and between contralesional thalamus and cerebellum. Conclusion The strength of connectivity between somatosensory regions and distributed brain networks, including vision and attention networks, may change over time in stroke survivors with impaired touch discrimination. Connectivity changes from contralesional SII and contralesional thalamus are associated with improved touch sensation at 6 months post-stroke. These functional connectivity changes could represent future targets for therapy.
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Affiliation(s)
- Louise C Bannister
- Neurorehabilitation and Recovery, Stroke Division, Florey Institute of Neuroscience and Mental Health , Melbourne, VIC , Australia ; School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University , Melbourne, VIC , Australia ; Occupational Therapy, School of Allied Health, College of Science, Health and Engineering, La Trobe University , Melbourne, VIC , Australia
| | - Sheila G Crewther
- School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University , Melbourne, VIC , Australia
| | - Maria Gavrilescu
- Neurorehabilitation and Recovery, Stroke Division, Florey Institute of Neuroscience and Mental Health , Melbourne, VIC , Australia ; Defence Science and Technology Organisation , Melbourne, VIC , Australia
| | - Leeanne M Carey
- Neurorehabilitation and Recovery, Stroke Division, Florey Institute of Neuroscience and Mental Health , Melbourne, VIC , Australia ; Occupational Therapy, School of Allied Health, College of Science, Health and Engineering, La Trobe University , Melbourne, VIC , Australia ; Florey Department of Neuroscience and Mental Health, The University of Melbourne , Melbourne, VIC , Australia
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Chu RKO, Braun AR, Meltzer JA. MEG-based detection and localization of perilesional dysfunction in chronic stroke. NEUROIMAGE-CLINICAL 2015; 8:157-69. [PMID: 26106540 PMCID: PMC4473381 DOI: 10.1016/j.nicl.2015.03.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 03/20/2015] [Accepted: 03/23/2015] [Indexed: 11/13/2022]
Abstract
Post-stroke impairment is associated not only with structural lesions, but also with dysfunction in surviving perilesional tissue. Previous studies using equivalent current dipole source localization of MEG/EEG signals have demonstrated a preponderance of slow-wave activity localized to perilesional areas. Recent studies have also demonstrated the utility of nonlinear analyses such as multiscale entropy (MSE) for quantifying neuronal dysfunction in a wide range of pathologies. The current study utilized beamformer-based reconstruction of signals in source space to compare spectral and nonlinear measures of electrical activity in perilesional and healthy cortices. Data were collected from chronic stroke patients and healthy controls, both young and elderly. We assessed relative power in the delta (1–4 Hz), theta (4–7 Hz), alpha (8–12 Hz) and beta (15–30 Hz) frequency bands, and also measured the nonlinear complexity of electrical activity using MSE. Perilesional tissue exhibited a general slowing of the power spectrum (increased delta/theta, decreased beta) as well as a reduction in MSE. All measures tested were similarly sensitive to changes in the posterior perilesional regions, but anterior perilesional dysfunction was detected better by MSE and beta power. The findings also suggest that MSE is specifically sensitive to electrophysiological dysfunction in perilesional tissue, while spectral measures were additionally affected by an increase in rolandic beta power with advanced age. Furthermore, perilesional electrophysiological abnormalities in the left hemisphere were correlated with the degree of language task-induced activation in the right hemisphere. Finally, we demonstrate that single subject spectral and nonlinear analyses can identify dysfunctional perilesional regions within individual patients that may be ideal targets for interventions with noninvasive brain stimulation. We assessed the spontaneous MEG activity of perilesional tissue in stroke. We observed perilesional spectral slowing and reduced signal complexity. We demonstrate a method to identify dysfunctional tissue within a single subject.
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Affiliation(s)
- Ron K O Chu
- University of Toronto, Department of Psychology, 100 St. George Street, 4th Floor, Sidney Smith Hall, Toronto, ON M5S 3G3, Canada ; Rotman Research Institute, Baycrest Centre, 3560 Bathurst St., Toronto, ON M6A 2E1, Canada
| | - Allen R Braun
- Language Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Jed A Meltzer
- University of Toronto, Department of Psychology, 100 St. George Street, 4th Floor, Sidney Smith Hall, Toronto, ON M5S 3G3, Canada ; University of Toronto, Department of Speech-Language Pathology, 160-500 University Avenue, Toronto, ON M5G 1V7, Canada ; Rotman Research Institute, Baycrest Centre, 3560 Bathurst St., Toronto, ON M6A 2E1, Canada ; Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, 600 Peter Morand Cres., Suite 201, Ottawa, ON K1G 5Z3, Canada
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Kwon YH, Lee MY. Changes in cortical activation patterns accompanying somatosensory recovery in a stroke patient: a functional magnetic resonance imaging study. Neural Regen Res 2014; 9:1485-8. [PMID: 25317161 PMCID: PMC4192951 DOI: 10.4103/1673-5374.139468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2014] [Indexed: 11/08/2022] Open
Affiliation(s)
- Yong Hyun Kwon
- Department of Physical Therapy, Yeungnam University College, Namgu, Daegu, 705-703, Republic of Korea
| | - Mi Young Lee
- Department of Physical Therapy, College of Health and Therapy, Daegu Haany University, Gyeongsan-si, Gyeongsangbuk-do, 712-715, Republic of Korea
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Neuromagnetic beta and gamma oscillations in the somatosensory cortex after music training in healthy older adults and a chronic stroke patient. Clin Neurophysiol 2013; 125:1213-22. [PMID: 24290848 DOI: 10.1016/j.clinph.2013.10.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 10/17/2013] [Accepted: 10/21/2013] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Extensive rehabilitation training can lead to functional improvement even years after a stroke. Although neuronal plasticity is considered as a main origin of such ameliorations, specific subtending mechanisms need further investigation. Our aim was to obtain objective neuromagnetic measures sensitive to brain reorganizations induced by a music-supported training. METHODS We applied 20-Hz vibrotactile stimuli to the index finger and the ring finger, recorded somatosensory steady-state responses with magnetoencephalography, and analyzed the cortical sources displaying oscillations synchronized with the external stimuli in two groups of healthy older adults before and after musical training or without training. In addition, we applied the same analysis for an anecdotic report of a single chronic stroke patient with hemiparetic arm and hand problems, who received music-supported therapy (MST). RESULTS Healthy older adults showed significant finger separation within the primary somatotopic map. Beta dipole sources were more anterior located compared to gamma sources. An anterior shift of sources and increases in synchrony between the stimuli and beta and gamma oscillations were observed selectively after music training. In the stroke patient a normalization of somatotopic organization was observed after MST, with digit separation recovered after training and stimulus induced gamma synchrony increased. CONCLUSIONS The proposed stimulation paradigm captures the integrity of primary somatosensory hand representation. Source position and synchronization between the stimuli and gamma activity are indices, sensitive to music-supported training. Responsiveness was also observed in a chronic stroke patient, encouraging for the music-supported therapy. Notably, changes in somatosensory responses were observed, even though the therapy did not involve specific sensory discrimination training. SIGNIFICANCE The proposed protocol can be used for monitoring changes in neuronal organization during training and will improve the understanding of the brain mechanisms underlying rehabilitation.
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Somatotopic finger mapping using MEG: toward an optimal stimulation paradigm. Clin Neurophysiol 2013; 124:1659-70. [PMID: 23518470 DOI: 10.1016/j.clinph.2013.01.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/19/2012] [Accepted: 01/15/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE In non-invasive somatotopic mapping based on neuromagnetic source analysis, the recording time can be shortened and accuracy improved by applying simultaneously vibrotactile stimuli at different frequencies to multiple body sites and recording multiple steady-state responses. This study compared the reliability of sensory evoked responses, source localization performance, and reproducibility of digit maps for three different stimulation paradigms. METHODS Vibrotactile stimuli were applied to the fingertip and neuromagnetic steady-state responses were recorded. Index and middle fingers were stimulated either sequentially in separate blocks, simultaneously at different frequencies, or in alternating temporal order within a block. RESULTS Response amplitudes were largest and source localization was most accurate between 21 and 23 Hz. Separation of adjacent digits was significant for all paradigms in all participants. Suppressive interactions occurred between simultaneously applied stimuli. However, when frequently alternating between stimulus sites, the higher stimulus novelty resulted in increased amplitudes and superior localization performance. CONCLUSIONS When receptive fields are strongly overlapping, the alternating stimulation is preferable over recording multiple steady state responses. SIGNIFICANCE The new paradigm improved the measurement of the distance of somatotopic finger representation in human primary somatosensory cortex, which is an important metric for neuroplastic reorganization after learning and rehabilitation training.
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Sztriha LK, O'Gorman RL, Modo M, Barker GJ, Williams SCR, Kalra L. Monitoring brain repair in stroke using advanced magnetic resonance imaging. Stroke 2012; 43:3124-31. [PMID: 23010674 DOI: 10.1161/strokeaha.111.649244] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Laszlo K Sztriha
- Department of clinical Neuroscience, Institute of Psychiatry, King's College London, Denmark Hill, SE5 8AF, London, UK.
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Abstract
Stroke represents a major cause of death and disability. In just the last two decades, science has begun to appreciate the central nervous system's attempts to repair itself through a process termed neuroplasticity. The remodeling is a dynamic process subject to endogenous and exogenous forces. Rehabilitation has started to implement approaches based on objective measures such as diffusion tensor imaging and functional magnetic resonance. Newer modalities such as constraint-induced movement therapy and robotic interventions are being used for both short- and long-term functional gains. This review describes the various studies on neuroplasticity and the variety of interventions now available.
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Physiological aging impacts the hemispheric balances of resting state primary somatosensory activities. Brain Topogr 2012; 26:186-99. [PMID: 22760422 DOI: 10.1007/s10548-012-0240-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 06/21/2012] [Indexed: 10/28/2022]
Abstract
To hone knowledge of sensorimotor cerebral organization changes with physiological aging, we focused on the primary somatosensory cortical area (S1). S1 neuronal pools (FS_S1) were identified by the functional source separation (FSS) algorithm applied to magnetoencephalographic recordings during median nerve stimulation. Age-dependence of FS_S1 was then studied at rest separately in the left and right hemispheres of 26 healthy, right-handed subjects between the ages of 24 and 95 years. The resting state FS_S1 spectral features changed with increasing age: (1) alpha activity slowed down; (2) total power increased only in the right hemisphere; (3) right>left interhemispheric asymmetry increased in the whole spectrum; (4) spectral entropy increased with age selectively in the left hemisphere. The present FSS-enriched electrophysiological procedure provided measures of resting state hand representation area sensitive to changes with age. Alterations were stronger in the right hemisphere. Relationships between resting state S1 activity and its responsiveness to external stimuli, revealed that the interhemispheric unbalances which emerged with age were conceivably due to an increased excitability within the right thalamocortical circuit impacting left versus right unbalances of spontaneous firing rates and of local inhibitory-excitatory networks.
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