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MacKenzie EG, Snow NJ, Chaves AR, Reza SZ, Ploughman M. Weak grip strength among persons with multiple sclerosis having minimal disability is not related to agility or integrity of the corticospinal tract. Mult Scler Relat Disord 2024; 88:105741. [PMID: 38936325 DOI: 10.1016/j.msard.2024.105741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 05/23/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024]
Abstract
INTRODUCTION Mobility impairment is common in multiple sclerosis (MS); however, agility has received less attention. Agility requires strength and neuromuscular coordination to elicit controlled propulsive rapid whole-body movement. Grip strength is a common method to assess whole body force production, but also reflects neuromuscular integrity and global brain health. Impaired agility may be linked to loss of neuromuscular integrity (reflected by grip strength or corticospinal excitability). OBJECTIVES We aimed to determine whether grip strength would be associated with agility and transcranial magnetic stimulation (TMS)-based indices of corticospinal excitability and inhibition in persons with MS having low disability. We hypothesized that low grip strength would predict impaired agility and reflect low corticospinal excitability. METHODS We recruited 34 persons with relapsing MS (27 females; median [range] age 45.5 [21.0-65.0] years) and mild disability (median [range] Expanded Disability Status Scale 2.0 [0-3.0]), as well as a convenience sample of age- and sex-matched apparently healthy controls. Agility was tested by measuring hop length during bipedal hopping on an instrumented walkway. Grip strength was measured using a calibrated dynamometer. Corticospinal excitability and inhibition were examined using TMS-based motor evoked potential (MEP) and corticospinal silent period (CSP) recruitment curves, respectively. RESULTS MS participants had significantly lower grip strength than controls independent of sex. Females with and without MS had weaker grip strength than males. There were no statistically significant sex or group differences in agility. After controlling for sex, weaker grip strength was associated with shorter hop length in controls only (r = 0.645, p < .05). Grip strength did not significantly predict agility in persons with MS, nor was grip strength predicted by corticospinal excitability or inhibition. CONCLUSIONS In persons with MS having low disability, grip strength (normalized to body mass) was reduced despite having intact agility and walking performance. Grip strength was not associated with corticospinal excitability or inhibition, suggesting peripheral neuromuscular function, low physical activity or fitness, or other psychosocial factors may be related to weakness. Low grip strength is a putative indicator of early neuromuscular aging in persons with MS having mild disability and normal mobility.
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Affiliation(s)
- Evan G MacKenzie
- Faculty of Medicine, Recovery & Performance Laboratory, Memorial University of Newfoundland and Labrador, Room 400, L.A. Miller Center, 100 Forest Road, St. John's, St. John's, NL A1A 1E5, Canada
| | - Nicholas J Snow
- Faculty of Medicine, Recovery & Performance Laboratory, Memorial University of Newfoundland and Labrador, Room 400, L.A. Miller Center, 100 Forest Road, St. John's, St. John's, NL A1A 1E5, Canada
| | - Arthur R Chaves
- Faculty of Health Sciences, Interdisciplinary School of Health Sciences, University of Ottawa, ON, Canada; Neuromodulation Research Clinic, The Royal's Institute of Mental Health Research, ON, Canada; Département de Psychoéducation et de Psychologie, Université du Québec en Outaouais, QC, Canada
| | - Syed Z Reza
- Faculty of Medicine, Recovery & Performance Laboratory, Memorial University of Newfoundland and Labrador, Room 400, L.A. Miller Center, 100 Forest Road, St. John's, St. John's, NL A1A 1E5, Canada
| | - Michelle Ploughman
- Faculty of Medicine, Recovery & Performance Laboratory, Memorial University of Newfoundland and Labrador, Room 400, L.A. Miller Center, 100 Forest Road, St. John's, St. John's, NL A1A 1E5, Canada.
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Alkadhi KA. Synaptic Plasticity and Cognitive Ability in Experimental Adult-Onset Hypothyroidism. J Pharmacol Exp Ther 2024; 389:150-162. [PMID: 38508752 DOI: 10.1124/jpet.123.001887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 02/05/2024] [Accepted: 02/20/2024] [Indexed: 03/22/2024] Open
Abstract
Adult-onset hypothyroidism impairs normal brain function. Research on animal models of hypothyroidism has revealed critical information on how deficiency of thyroid hormones impacts the electrophysiological and molecular functions of the brain, which leads to the well known cognitive impairment in untreated hypothyroid patients. Currently, such information can only be obtained from experiments on animal models of hypothyroidism. This review summarizes important research findings that pertain to understanding the clinical cognitive consequences of hypothyroidism, which will provide a better guiding path for therapy of hypothyroidism. SIGNIFICANCE STATEMENT: Cognitive impairment occurs during adult-onset hypothyroidism in both humans and animal models. Findings from animal studies validate clinical findings showing impaired long-term potentiation, decreased CaMKII, and increased calcineurin. Such findings can only be gleaned from animal experiments to show how hypothyroidism produces clinical symptoms.
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Affiliation(s)
- Karim A Alkadhi
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
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Huang L, Yi L, Huang H, Zhan S, Chen R, Yue Z. Corticospinal tract: a new hope for the treatment of post-stroke spasticity. Acta Neurol Belg 2024; 124:25-36. [PMID: 37704780 PMCID: PMC10874326 DOI: 10.1007/s13760-023-02377-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 08/30/2023] [Indexed: 09/15/2023]
Abstract
Stroke is the third leading cause of death and disability worldwide. Post-stroke spasticity (PSS) is the most common complication of stroke but represents only one of the many manifestations of upper motor neuron syndrome. As an upper motor neuron, the corticospinal tract (CST) is the only direct descending motor pathway that innervates the spinal motor neurons and is closely related to the recovery of limb function in patients with PSS. Therefore, promoting axonal remodeling in the CST may help identify new therapeutic strategies for PSS. In this review, we outline the pathological mechanisms of PSS, specifically their relationship with CST, and therapeutic strategies for axonal regeneration of the CST after stroke. We found it to be closely associated with astroglial scarring produced by astrocyte activation and its secretion of neurotrophic factors, mainly after the onset of cerebral ischemia. We hope that this review offers insight into the relationship between CST and PSS and provides a basis for further studies.
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Affiliation(s)
- Linxing Huang
- College of Acupuncture, Massage and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Lizhen Yi
- College of Acupuncture, Massage and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Huiyuan Huang
- College of Acupuncture, Massage and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Sheng Zhan
- College of Acupuncture, Massage and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Ruixue Chen
- College of Acupuncture, Massage and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Zenghui Yue
- College of Acupuncture, Massage and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China.
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Snow NJ, Landine J, Chaves AR, Ploughman M. Age and asymmetry of corticospinal excitability, but not cardiorespiratory fitness, predict cognitive impairments in multiple sclerosis. IBRO Neurosci Rep 2023; 15:131-142. [PMID: 37577407 PMCID: PMC10412844 DOI: 10.1016/j.ibneur.2023.07.002] [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: 11/11/2022] [Revised: 07/11/2023] [Accepted: 07/15/2023] [Indexed: 08/15/2023] Open
Abstract
Background Cognitive impairment is a disabling and underestimated consequence of multiple sclerosis (MS), with multiple determinants that are poorly understood. Objectives We explored predictors of MS-related processing speed impairment (PSI) and age-related mild cognitive impairment (MCI) and hypothesized that cardiorespiratory fitness and corticospinal excitability would predict these impairments. Methods We screened 73 adults with MS (53 females; median [range]: Age 48 [21-70] years, EDSS 2.0 [0.0-6.5]) for PSI and MCI using the Symbol Digit Modalities Test and Montréal Cognitive Assessment, respectively. We identified six persons with PSI (No PSI, n = 67) and 13 with MCI (No MCI, n = 60). We obtained clinical data from medical records and self-reports; used transcranial magnetic stimulation to test corticospinal excitability; and assessed cardiorespiratory fitness using a graded maximal exercise test. We used receiver operator characteristic (ROC) curves to discern predictors of PSI and MCI. Results Interhemispheric asymmetry of corticospinal excitability was specific for PSI, while age was both sensitive and specific for MCI. MS-related PSI was also associated with statin prescriptions, while age-related MCI was related to progressive MS and GABA agonist prescriptions. Cardiorespiratory fitness was associated with neither PSI nor MCI. Discussion Corticospinal excitability is a potential marker of neurodegeneration in MS-related PSI, independent of age-related effects on global cognitive function. Age is a key predictor of mild global cognitive impairment. Cardiorespiratory fitness did not predict cognitive impairments in this clinic-based sample of persons with MS.
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Affiliation(s)
- Nicholas J. Snow
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, Canada
| | - Josef Landine
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, Canada
| | - Arthur R. Chaves
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, Canada
| | - Michelle Ploughman
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland and Labrador, St. John's, Newfoundland and Labrador, Canada
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Khademi F, Naros G, Nicksirat A, Kraus D, Gharabaghi A. Rewiring Cortico-Muscular Control in the Healthy and Poststroke Human Brain with Proprioceptive β-Band Neurofeedback. J Neurosci 2022; 42:6861-6877. [PMID: 35940874 PMCID: PMC9463986 DOI: 10.1523/jneurosci.1530-20.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 06/02/2022] [Accepted: 06/04/2022] [Indexed: 11/21/2022] Open
Abstract
In severely affected stroke survivors, cortico-muscular control is disturbed and volitional upper limb movements often absent. Mental rehearsal of the impaired movement in conjunction with sensory feedback provision are suggested as promising rehabilitation exercises. Knowledge about the underlying neural processes, however, remains vague. In male and female chronic stroke patients with hand paralysis, a brain-computer interface controlled a robotic orthosis and turned sensorimotor β-band desynchronization during motor imagery (MI) of finger extension into contingent hand opening. Healthy control subjects performed the same task and received the same proprioceptive feedback with a robotic orthosis or visual feedback only. Only when proprioceptive feedback was provided, cortico-muscular coherence (CMC) increased with a predominant information flow from the sensorimotor cortex to the finger extensors. This effect (1) was specific to the β frequency band, (2) transferred to a motor task (MT), (3) was proportional to subsequent corticospinal excitability (CSE) and correlated with behavioral changes in the (4) healthy and (5) poststroke condition; notably, MI-related enhancement of β-band CMC in the ipsilesional premotor cortex correlated with motor improvements after the intervention. In the healthy and injured human nervous system, synchronized activation of motor-related cortical and spinal neural pools facilitates, in accordance with the communication-through-coherence hypothesis, cortico-spinal communication and may, thereby, be therapeutically relevant for functional restoration after stroke, when voluntary movements are no longer possible.SIGNIFICANCE STATEMENT This study provides insights into the neural processes that transfer effects of brain-computer interface neurofeedback to subsequent motor behavior. Specifically, volitional control of cortical oscillations and proprioceptive feedback enhances both cortical activity and behaviorally relevant connectivity to the periphery in a topographically circumscribed and frequency-specific way. This enhanced cortico-muscular control can be induced in the healthy and poststroke brain. Thereby, activating the motor cortex with mental rehearsal of the impaired movement and closing the loop by robot-assisted feedback synchronizes ipsilesional premotor cortex and spinal neural pools in the β frequency band. This facilitates, in accordance with the communication-through-coherence hypothesis, cortico-spinal communication and may, thereby, be therapeutically relevant for functional restoration after stroke, when voluntary movements are no longer possible.
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Affiliation(s)
- Fatemeh Khademi
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tübingen, Tübingen 72076, Germany
| | - Georgios Naros
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tübingen, Tübingen 72076, Germany
| | - Ali Nicksirat
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tübingen, Tübingen 72076, Germany
| | - Dominic Kraus
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tübingen, Tübingen 72076, Germany
| | - Alireza Gharabaghi
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tübingen, Tübingen 72076, Germany
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Saini M, Singh N, Kumar N, Srivastava MVP, Mehndiratta A. A novel perspective of associativity of upper limb motor impairment and cortical excitability in sub-acute and chronic stroke. Front Neurosci 2022; 16:832121. [PMID: 35958985 PMCID: PMC9358254 DOI: 10.3389/fnins.2022.832121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe global inclination of stroke onset in earlier years of life and increased lifespan have resulted in an increased chronic post-stroke-related disability. The precise and simplistic approach such as the correlation of Fugl-Meyer Assessment (FMA) with Transcranial Magnetic Stimulation (TMS) parameters, Resting Motor Threshold (RMT) and Motor Evoked Potential (MEP), in patients with stroke might play a critical role, given the prognostic value of MEP, a measure of cortical excitability, and might be the key point in prescribing appropriate therapeutic strategies.ObjectiveThe study aimed to determine the correlation of FMA-based impairment in the upper extremity function specifically of the wrist and hand with respect to the neurophysiological parameters of corticospinal tract integrity.Materials and methodsThe Institutional Review Board approved the study and 67 (n) patients with stroke were enrolled in the Department of Neurology, AIIMS, New Delhi, India. The motor assessment was performed on patients by the upper extremity subset of Fugl-Meyer Assessment (FMA) and the clinical history was obtained. RMT and MEP of Extensor Digitorum Communis (EDC) muscle were measured via TMS.ResultsA significant positive correlation was observed between Fugl-Meyer Assessment Wrist/Hand (FMA W/H) and MEP scores (r = 0.560, <0.001). Also, Fugl-Meyer Assessment Upper Extremity (FMA UE) scores demonstrated a moderate positive association with MEP responsiveness (r = 0.421, <0.001).ConclusionMEP of the EDC muscle was found to be associated with sensorimotor control as measured by FMA. Moreover, FMA W/H score values might be a better prognostic indicator of EDC MEP responsiveness. Interestingly, a novel element comprising the range of FMA UE and FMA W/H components was observed to be a potential indicator of MEP responsiveness and could also indicate establishing FMA as a surrogate for TMS in resource-limited settings for prognostification.
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Affiliation(s)
- Megha Saini
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Neha Singh
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Nand Kumar
- Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India
| | | | - Amit Mehndiratta
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India
- Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, India
- *Correspondence: Amit Mehndiratta,
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7
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Sheng W, Li S, Zhao J, Wang Y, Luo Z, Lo WLA, Ding M, Wang C, Li L. Upper Limbs Muscle Co-contraction Changes Correlated With the Impairment of the Corticospinal Tract in Stroke Survivors: Preliminary Evidence From Electromyography and Motor-Evoked Potential. Front Neurosci 2022; 16:886909. [PMID: 35720692 PMCID: PMC9198335 DOI: 10.3389/fnins.2022.886909] [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: 03/01/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022] Open
Abstract
Objective Increased muscle co-contraction of the agonist and antagonist muscles during voluntary movement is commonly observed in the upper limbs of stroke survivors. Much remain to be understood about the underlying mechanism. The aim of the study is to investigate the correlation between increased muscle co-contraction and the function of the corticospinal tract (CST). Methods Nine stroke survivors and nine age-matched healthy individuals were recruited. All the participants were instructed to perform isometric maximal voluntary contraction (MVC) and horizontal task which consist of sponge grasp, horizontal transportation, and sponge release. We recorded electromyography (EMG) activities from four muscle groups during the MVC test and horizontal task in the upper limbs of stroke survivors. The muscle groups consist of extensor digitorum (ED), flexor digitorum (FD), triceps brachii (TRI), and biceps brachii (BIC). The root mean square (RMS) of EMG was applied to assess the muscle activation during horizontal task. We adopted a co-contraction index (CI) to evaluate the degree of muscle co-contraction. CST function was evaluated by the motor-evoked potential (MEP) parameters, including resting motor threshold, amplitude, latency, and central motor conduction time. We employed correlation analysis to probe the association between CI and MEP parameters. Results The RMS, CI, and MEP parameters on the affected side showed significant difference compared with the unaffected side of stroke survivors and the healthy group. The result of correlation analysis showed that CI was significantly correlated with MEP parameters in stroke survivors. Conclusion There existed increased muscle co-contraction and impairment in CST functionality on the affected side of stroke survivors. The increased muscle co-contraction was correlated with the impairment of the CST. Intervention that could improve the excitability of the CST may contribute to the recovery of muscle discoordination in the upper limbs of stroke survivors.
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Affiliation(s)
- Wenfei Sheng
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Shijue Li
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jiangli Zhao
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yujia Wang
- Faculty of Science and Technology, University of Macau, Taipa, Macao SAR, China
| | - Zichong Luo
- Faculty of Science and Technology, University of Macau, Taipa, Macao SAR, China
| | - Wai Leung Ambrose Lo
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Minghui Ding
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Chuhuai Wang
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Le Li
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
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Shraim MA, Massé-Alarie H, Salomoni SE, Hodges PW. Can training of a skilled pelvic movement change corticomotor control of back muscles? Comparison of single and paired-pulse transcranial magnetic stimulation. Eur J Neurosci 2022; 56:3705-3719. [PMID: 35501123 PMCID: PMC9540878 DOI: 10.1111/ejn.15683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
Evidence suggests excitability of the motor cortex (M1) changes in response to motor skill learning of the upper limb. Few studies have examined immediate changes in corticospinal excitability and intra‐cortical mechanisms following motor learning in the lower back. Further, it is unknown which transcranial magnetic stimulation (TMS) paradigms are likely to reveal changes in cortical function in this region. This study aimed to (1) compare corticospinal excitability and intra‐cortical mechanisms in the lower back region of M1 before and after a single session of lumbopelvic tilt motor learning task in healthy people and (2) compare these measures between two TMS coils and two methods of recruitment curve (RC) acquisition. Twenty‐eight young participants (23.6 ± 4.6 years) completed a lumbopelvic tilting task involving three 5‐min blocks. Single‐pulse (RC from 70% to 150% of active motor threshold) and paired‐pulse TMS measures (ICF, SICF and SICI) were undertaken before (using 2 coils: figure‐of‐8 and double cone) and after (using double cone coil only) training. RCs were also acquired using a traditional and rapid method. A significant increase in corticospinal excitability was found after training as measured by RC intensities, but this was not related to the RC slope. No significant differences were found for paired‐pulse measures after training. Finally, there was good agreement between RC parameters when measured with the two different TMS coils or different acquisition methods (traditional vs. rapid). Changes in corticospinal excitability after a single session of lumbopelvic motor learning task are seen, but these changes are not explained by changes in intra‐cortical mechanisms.
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Affiliation(s)
- Muath A Shraim
- The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, School of Health & Rehabilitation Sciences, QLD, Australia
| | - Hugo Massé-Alarie
- The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, School of Health & Rehabilitation Sciences, QLD, Australia.,Centre interdisciplinaire de recherche en réadaptation et integration sociale (CIRRIS), Université Laval, Québec, QC, Canada
| | - Sauro E Salomoni
- The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, School of Health & Rehabilitation Sciences, QLD, Australia
| | - Paul W Hodges
- The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, School of Health & Rehabilitation Sciences, QLD, Australia
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Graterol Pérez JA, Guder S, Choe CU, Gerloff C, Schulz R. Relationship Between Cortical Excitability Changes and Cortical Thickness in Subcortical Chronic Stroke. Front Neurol 2022; 13:802113. [PMID: 35345406 PMCID: PMC8957093 DOI: 10.3389/fneur.2022.802113] [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: 10/26/2021] [Accepted: 01/31/2022] [Indexed: 11/21/2022] Open
Abstract
Ischemic stroke leads to excitability changes of the motor network as probed by means of transcranial magnetic stimulation (TMS). There is still limited data that shows to what extent structural alterations of the motor network might be linked to excitability changes. Previous results argue that the microstructural state of specific corticofugal motor tracts such as the corticospinal tract associate with cortical excitability in chronic stroke patients. The relationship between changes of cortical anatomy after stroke, as operationalized by means of decreases or increases in local cortical thickness (CT), has scarcely been addressed. In the present study, we re-analyzed TMS data and recruitment curve properties of motor evoked potentials and CT data in a group of 14 well-recovered chronic stroke patients with isolated supratentorial subcortical lesions. CT data of the stroke patients were compared to CT data of 17 healthy controls. Whole-brain and region-of-interest based analyses were conducted to relate CT data to measures of motor cortical excitability and clinical data. We found that stroke patients exhibited significantly reduced CT not only in the ipsilesional primary motor cortex but also in numerous secondary motor and non-motor brain regions, particularly in the ipsilesional hemisphere including areas along the central sulcus, the inferior frontal sulcus, the intraparietal sulcus, and cingulate cortices. We could not detect any significant relationship between the extent of CT reduction and stroke-related excitability changes of the motor network or clinical scores.
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Affiliation(s)
- José A Graterol Pérez
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stephanie Guder
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Chi-Un Choe
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Gerloff
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Robert Schulz
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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10
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Chaves AR, Kenny HM, Snow NJ, Pretty RW, Ploughman M. Sex-specific disruption in corticospinal excitability and hemispheric (a)symmetry in multiple sclerosis. Brain Res 2021; 1773:147687. [PMID: 34634288 DOI: 10.1016/j.brainres.2021.147687] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 02/06/2023]
Abstract
Multiple Sclerosis (MS) is a neurodegenerative disease in which pathophysiology and symptom progression presents differently between the sexes. In a cohort of people with MS (n = 110), we used transcranial magnetic stimulation (TMS) to investigate sex differences in corticospinal excitability (CSE) and sex-specific relationships between CSE and cognitive function. Although demographics and disease characteristics did not differ between sexes, males were more likely to have cognitive impairment as measured by the Montreal Cognitive Assessment (MoCA); 53.3% compared to females at 26.3%. Greater CSE asymmetry was noted in females compared to males. Females demonstrated higher active motor thresholds and longer silent periods in the hemisphere corresponding to the weaker hand which was more typical of hand dominance patterns in healthy individuals. Males, but not females, exhibited asymmetry of nerve conduction latency (delayed MEP latency in the hemisphere corresponding to the weaker hand). In males, there was also a relationship between delayed onset of ipsilateral silent period (measured in the hemisphere corresponding to the weaker hand) and MoCA, suggestive of cross-callosal disruption. Our findings support that a sex-specific disruption in CSE exists in MS, pointing to interhemispheric disruption as a potential biomarker of cognitive impairment and target for neuromodulating therapies.
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Affiliation(s)
- Arthur R Chaves
- Recovery and Performance Laboratory, Faculty of Medicine, L.A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - Hannah M Kenny
- Recovery and Performance Laboratory, Faculty of Medicine, L.A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - Nicholas J Snow
- Recovery and Performance Laboratory, Faculty of Medicine, L.A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - Ryan W Pretty
- Recovery and Performance Laboratory, Faculty of Medicine, L.A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - Michelle Ploughman
- Recovery and Performance Laboratory, Faculty of Medicine, L.A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
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Viganò L, Howells H, Rossi M, Rabuffetti M, Puglisi G, Leonetti A, Bellacicca A, Conti Nibali M, Gay L, Sciortino T, Cerri G, Bello L, Fornia L. Stimulation of frontal pathways disrupts hand muscle control during object manipulation. Brain 2021; 145:1535-1550. [PMID: 34623420 PMCID: PMC9128819 DOI: 10.1093/brain/awab379] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/20/2021] [Accepted: 09/15/2021] [Indexed: 11/13/2022] Open
Abstract
The activity of frontal motor areas during hand-object interaction is coordinated by dense communication along specific white matter pathways. This architecture allows the continuous shaping of voluntary motor output and, despite extensively investigated in non-human primate studies, remains poorly understood in humans. Disclosure of this system is crucial for predicting and treatment of motor deficits after brain lesions. For this purpose, we investigated the effect of direct electrical stimulation on white matter pathways within the frontal lobe on hand-object manipulation. This was tested in thirty-four patients (15 left hemisphere, mean age 42 years, 17 male, 15 with tractography) undergoing awake neurosurgery for frontal lobe tumour removal with the aid of the brain mapping technique. The stimulation outcome was quantified based on hand-muscle activity required by task execution. The white matter pathways responsive to stimulation with an interference on muscles were identified by means of probabilistic density estimation of stimulated sites, tract-based lesion-symptom (disconnectome) analysis and diffusion tractography on the single patient level. Finally, we assessed the effect of permanent tracts disconnection on motor outcome in the immediate postoperative period using a multivariate lesion-symptom mapping approach. The analysis showed that stimulation disrupted hand-muscle activity during task execution in 66 sites within the white matter below dorsal and ventral premotor regions. Two different EMG interference patterns associated with different structural architectures emerged: 1) an arrest pattern, characterised by complete impairment of muscle activity associated with an abrupt task interruption, occurred when stimulating a white matter area below the dorsal premotor region. Local mid-U-shaped fibres, superior fronto-striatal, corticospinal and dorsal fronto-parietal fibres intersected with this region. 2) a clumsy pattern, characterised by partial disruption of muscle activity associated with movement slowdown and/or uncoordinated finger movements, occurred when stimulating a white matter area below the ventral premotor region. Ventral fronto-parietal and inferior fronto-striatal tracts intersected with this region. Finally, only resections partially including the dorsal white matter region surrounding the supplementary motor area were associated with transient upper-limb deficit (p = 0.05; 5000 permutations). Overall, the results identify two distinct frontal white matter regions possibly mediating different aspects of hand-object interaction via distinct sets of structural connectivity. We suggest the dorsal region, associated with arrest pattern and post-operative immediate motor deficits, to be functionally proximal to motor output implementation, while the ventral region may be involved in sensorimotor integration required for task execution.
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Affiliation(s)
- Luca Viganò
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Henrietta Howells
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, Universita`degli Studi di Milano
| | - Marco Rossi
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Marco Rabuffetti
- Biomedical Technology Department, IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milano, Italy
| | - Guglielmo Puglisi
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano.,MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, Universita`degli Studi di Milano
| | - Antonella Leonetti
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Andrea Bellacicca
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, Universita`degli Studi di Milano
| | - Marco Conti Nibali
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Lorenzo Gay
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Tommaso Sciortino
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Gabriella Cerri
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, Universita`degli Studi di Milano
| | - Lorenzo Bello
- Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano
| | - Luca Fornia
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, Universita`degli Studi di Milano
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12
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Cash RFH, Udupa K, Gunraj CA, Mazzella F, Daskalakis ZJ, Wong AHC, Kennedy JL, Chen R. Influence of BDNF Val66Met polymorphism on excitatory-inhibitory balance and plasticity in human motor cortex. Clin Neurophysiol 2021; 132:2827-2839. [PMID: 34592560 DOI: 10.1016/j.clinph.2021.07.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/30/2021] [Accepted: 07/27/2021] [Indexed: 01/23/2023]
Abstract
OBJECTIVE While previous studies showed that the single nucleotide polymorphism (Val66Met) of brain-derived neurotrophic factor (BDNF) can impact neuroplasticity, the influence of BDNF genotype on cortical circuitry and relationship to neuroplasticity remain relatively unexplored in human. METHODS Using individualised transcranial magnetic stimulation (TMS) parameters, we explored the influence of the BDNF Val66Met polymorphism on excitatory and inhibitory neural circuitry, its relation to I-wave TMS (ITMS) plasticity and effect on the excitatory/inhibitory (E/I) balance in 18 healthy individuals. RESULTS Excitatory and inhibitory indexes of neurotransmission were reduced in Met allele carriers. An E/I balance was evident, which was influenced by BDNF with higher E/I ratios in Val/Val homozygotes. Both long-term potentiation (LTP-) and depression (LTD-) like ITMS plasticity were greater in Val/Val homozygotes. LTP- but not LTD-like effects were restored in Met allele carriers by increasing stimulus intensity to compensate for reduced excitatory transmission. CONCLUSIONS The influence of BDNF genotype may extend beyond neuroplasticity to neurotransmission. The E/I balance was evident in human motor cortex, modulated by BDNF and measurable using TMS. Given the limited sample, these preliminary findings warrant further investigation. SIGNIFICANCE These novel findings suggest a broader role of BDNF genotype on neurocircuitry in human motor cortex.
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Affiliation(s)
- R F H Cash
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Brain Institute, Toronto, Ontario, Canada; Melbourne Neuropsychiatry Centre, The University of Melbourne, Victoria 3010, Australia; Department of Biomedical Engineering, The University of Melbourne, Victoria 3010, Australia.
| | - K Udupa
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Brain Institute, Toronto, Ontario, Canada; Dept of Neurophysiology, NIMHANS, Bengaluru, India
| | - C A Gunraj
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Brain Institute, Toronto, Ontario, Canada
| | - F Mazzella
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Brain Institute, Toronto, Ontario, Canada
| | - Z J Daskalakis
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, UC San Diego Health, San Diego, CA 92093, USA
| | - A H C Wong
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - J L Kennedy
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - R Chen
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Brain Institute, Toronto, Ontario, Canada
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13
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Guder S, Frey BM, Backhaus W, Braass H, Timmermann JE, Gerloff C, Schulz R. The Influence of Cortico-Cerebellar Structural Connectivity on Cortical Excitability in Chronic Stroke. Cereb Cortex 2021; 30:1330-1344. [PMID: 31647536 DOI: 10.1093/cercor/bhz169] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/17/2019] [Accepted: 06/22/2019] [Indexed: 12/11/2022] Open
Abstract
Brain imaging has recently evidenced that the structural state of distinct reciprocal cortico-cerebellar fiber tracts, the dentato-thalamo-cortical tract (DTCT), and the cortico-ponto-cerebellar tract (CPCeT), significantly influences residual motor output in chronic stroke patients, independent from the level of damage to the corticospinal tract (CST). Whether such structural information might also directly relate to measures of cortical excitability is an open question. Eighteen chronic stroke patients with supratentorial ischemic lesions and 17 healthy controls underwent transcranial magnetic stimulation to assess recruitment curves of motor evoked potentials of both hemispheres. Diffusion-weighted imaging and probabilistic tractography were applied to reconstruct reciprocal cortico-cerebellar motor tracts between the primary motor cortex and the cerebellum. Tract-related microstructure was estimated by means of fractional anisotropy, and linear regression modeling was used to relate it to cortical excitability. The main finding was a significant association between cortical excitability and the structural integrity of the DTCT, the main cerebellar outflow tract, independent from the level of damage to the CST. A comparable relationship was neither detectable for the CPCeT nor for the healthy controls. This finding contributes to a mechanistic understanding of the putative supportive role of the cerebellum for residual motor output by facilitating cortical excitability after stroke.
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Affiliation(s)
- Stephanie Guder
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Benedikt M Frey
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Winifried Backhaus
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Hanna Braass
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Jan E Timmermann
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Christian Gerloff
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Robert Schulz
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
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14
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Mohammad Mahdi Alavi S, Goetz SM, Saif M. Input-output slope curve estimation in neural stimulation based on optimal sampling principles . J Neural Eng 2021; 18:10.1088/1741-2552/abffe5. [PMID: 33975287 PMCID: PMC8384062 DOI: 10.1088/1741-2552/abffe5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/11/2021] [Indexed: 11/11/2022]
Abstract
This paper discusses some of the practical limitations and issues, which exist for the input-output (IO) slope curve estimation (SCE) in neural, brain and spinal, stimulation techniques. The drawbacks of the SCE techniques by using existing uniform sampling and Fisher-information-based optimal IO curve estimation (FO-IOCE) methods are elaborated. A novel IO SCE technique is proposed with a modified sampling strategy and stopping rule which improve the SCE performance compared to these methods. The effectiveness of the proposed IO SCE is tested on 1000 simulation runs in transcranial magnetic stimulation (TMS), with a realistic model of motor evoked potentials. The results show that the proposed IO SCE method successfully satisfies the stopping rule, before reaching the maximum number of TMS pulses in 79.5% of runs, while the estimation based on the uniform sampling technique never converges and satisfies the stopping rule. At the time of successful termination, the proposed IO SCE method decreases the 95th percentile (mean value in the parentheses) of the absolute relative estimation errors (AREs) of the slope curve parameters up to 7.45% (2.2%), with only 18 additional pulses on average compared to that of the FO-IOCE technique. It also decreases the 95th percentile (mean value in the parentheses) of the AREs of the IO slope curve parameters up to 59.33% (16.71%), compared to that of the uniform sampling method. The proposed IO SCE also identifies the peak slope with higher accuracy, with the 95th percentile (mean value in the parentheses) of AREs reduced by up to 9.96% (2.01%) compared to that of the FO-IOCE method, and by up to 46.29% (13.13%) compared to that of the uniform sampling method.
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Affiliation(s)
- Seyed Mohammad Mahdi Alavi
- Department of Applied Computing and Engineering, School of Technologies, Cardiff Metropolitan University, Llandaff Campus, Western Avenue, Cardiff CF5 2YB, United Kingdom
| | - Stefan M Goetz
- Departments of Psychiatry and Behavioral Sciences, Electrical and Computer Engineering, and Neurosurgery as well as the Duke Brain Initiative, Duke University, Durham, NC 27708, United States of America
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
| | - Mehrdad Saif
- Department of Electrical Engineering, University of Windsor, Windsor, ON N9B 3P4, Canada
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15
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Guder S, Pasternak O, Gerloff C, Schulz R. Strengthened structure-function relationships of the corticospinal tract by free water correction after stroke. Brain Commun 2021; 3:fcab034. [PMID: 33959708 PMCID: PMC8088790 DOI: 10.1093/braincomms/fcab034] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/23/2020] [Accepted: 01/27/2021] [Indexed: 11/23/2022] Open
Abstract
The corticospinal tract is the most intensively investigated tract of the human motor system in stroke rehabilitative research. Diffusion-tensor-imaging gives insights into its microstructure, and transcranial magnetic stimulation assesses its excitability. Previous data on the interrelationship between both measures are contradictory. Correlative or predictive models which associate them with motor outcome are incomplete. Free water correction has been developed to enhance diffusion-tensor-imaging by eliminating partial volume with extracellular water, which could improve capturing stroke-related microstructural alterations, thereby also improving structure-function relationships in clinical cohorts. In the present cross-sectional study, data of 18 chronic stroke patients and 17 healthy controls, taken from a previous study on cortico-cerebellar motor tracts, were re-analysed: The data included diffusion-tensor-imaging data quantifying corticospinal tract microstructure with and without free water correction, transcranial magnetic stimulation data assessing recruitment curve properties of motor evoked potentials and detailed clinical data. Linear regression modelling was used to interrelate corticospinal tract microstructure, recruitment curves properties and clinical scores. The main finding of the present study was that free water correction substantially strengthens structure-function associations in stroke patients: Specifically, our data evidenced a significant association between fractional anisotropy of the ipsilesional corticospinal tract and its excitability (P = 0.001, adj. R2 = 0.54), with free water correction explaining additional 20% in recruitment curve variability. For clinical scores, only free water correction leads to the reliable detection of significant correlations between ipsilesional corticospinal tract fractional anisotropy and residual grip (P = 0.001, adj. R2 = 0.70) and pinch force (P < 0.001, adj. R2 = 0.72). Finally, multimodal models can be improved by free water correction as well. This study evidences that corticospinal tract microstructure directly relates to its excitability in stroke patients. It also shows that unexplained variance in motor outcome is considerably reduced by free water correction arguing that it might serve as a powerful tool to improve existing models of structure-function associations and potentially also outcome prediction after stroke.
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Affiliation(s)
- Stephanie Guder
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Ofer Pasternak
- Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Christian Gerloff
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Robert Schulz
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
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16
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Chaves AR, Snow NJ, Alcock LR, Ploughman M. Probing the Brain-Body Connection Using Transcranial Magnetic Stimulation (TMS): Validating a Promising Tool to Provide Biomarkers of Neuroplasticity and Central Nervous System Function. Brain Sci 2021; 11:384. [PMID: 33803028 PMCID: PMC8002717 DOI: 10.3390/brainsci11030384] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 01/18/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive method used to investigate neurophysiological integrity of the human neuromotor system. We describe in detail, the methodology of a single pulse TMS protocol that was performed in a large cohort of people (n = 110) with multiple sclerosis (MS). The aim was to establish and validate a core-set of TMS variables that predicted typical MS clinical outcomes: walking speed, hand dexterity, fatigue, and cognitive processing speed. We provide a brief and simple methodological pipeline to examine excitatory and inhibitory corticospinal mechanisms in MS that map to clinical status. Delayed and longer ipsilateral silent period (a measure of transcallosal inhibition; the influence of one brain hemisphere's activity over the other), longer cortical silent period (suggestive of greater corticospinal inhibition via GABA) and higher resting motor threshold (lower corticospinal excitability) most strongly related to clinical outcomes, especially when measured in the hemisphere corresponding to the weaker hand. Greater interhemispheric asymmetry (imbalance between hemispheres) correlated with poorer performance in the greatest number of clinical outcomes. We also show, not surprisingly, that TMS variables related more strongly to motor outcomes than non-motor outcomes. As it was validated in a large sample of patients with varying severities of central nervous system dysfunction, the protocol described herein can be used by investigators and clinicians alike to investigate the role of TMS as a biomarker in MS and other central nervous system disorders.
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Affiliation(s)
| | | | | | - Michelle Ploughman
- L.A. Miller Centre, Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1A 1E5, Canada; (A.R.C.); (N.J.S.); (L.R.A.)
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17
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Effect of transcranial direct current stimulation on post-stroke fatigue. J Neurol 2021; 268:2831-2842. [PMID: 33598767 PMCID: PMC8289762 DOI: 10.1007/s00415-021-10442-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/03/2023]
Abstract
Background Fatigue is one of the most commonly reported symptoms post-stroke, which has a severe impact on the quality of life. Post-stroke fatigue is associated with reduced motor cortical excitability, specifically of the affected hemisphere. Objective The aim of this exploratory study was to assess whether fatigue symptoms can be reduced by increasing cortical excitability using anodal transcranial direct current stimulation (tDCS). Methods In this sham-controlled, double-blind intervention study, tDCS was applied bilaterally over the primary motor cortex in a single session in thirty stroke survivors with high severity of fatigue. A questionnaire-based measure of trait fatigue (primary outcome) was obtained before, after a week and 5 weeks post stimulation. Secondary outcome measures of state fatigue, motor cortex neurophysiology and perceived effort were also assessed pre, immediately post, a week and 5 weeks post stimulation. Results Anodal tDCS significantly improved fatigue symptoms a week after real stimulation when compared to sham stimulation. There was also a significant change in motor cortex neurophysiology of the affected hemisphere and perceived effort, a week after stimulation. The degree of improvement in fatigue was associated with baseline anxiety levels. Conclusion A single session of anodal tDCS improves fatigue symptoms with the effect lasting up to a week post stimulation. tDCS may therefore be a useful tool for managing fatigue symptoms post-stroke. Trial registration NCT04634864 Date of registration 17/11/2020–“retrospectively registered”.
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18
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Hordacre B, Lotze M, Jenkinson M, Lazari A, Barras CD, Boyd L, Hillier S. Fronto-parietal involvement in chronic stroke motor performance when corticospinal tract integrity is compromised. NEUROIMAGE-CLINICAL 2021; 29:102558. [PMID: 33513561 PMCID: PMC7841401 DOI: 10.1016/j.nicl.2021.102558] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/16/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Preserved integrity of the corticospinal tract (CST) is a marker of good upper-limb behavior and recovery following stroke. However, there is less understanding of neural mechanisms that might help facilitate upper-limb motor recovery in stroke survivors with extensive CST damage. OBJECTIVE The purpose of this study was to investigate resting state functional connectivity in chronic stroke survivors with different levels of CST damage and to explore neural correlates of greater upper-limb motor performance in stroke survivors with compromised ipsilesional CST integrity. METHODS Thirty chronic stroke survivors (24 males, aged 64.7 ± 10.8 years) participated in this study. Three experimental sessions were conducted to: 1) obtain anatomical (T1, T2) structural (diffusion) and functional (resting state) MRI sequences, 2) determine CST integrity with transcranial magnetic stimulation (TMS) and conduct assessments of upper-limb behavior, and 3) reconfirm CST integrity status. Participants were divided into groups according to the extent of CST damage. Those in the extensive CST damage group did not show TMS evoked responses and had significantly lower ipsilesional fractional anisotropy. RESULTS Of the 30 chronic stroke survivors, 12 were categorized as having extensive CST damage. Stroke survivors with extensive CST damage had weaker functional connectivity in the ipsilesional sensorimotor network and greater functional connectivity in the ipsilesional fronto-parietal network compared to those with preserved CST integrity. For participants with extensive CST damage, improved motor performance was associated with greater functional connectivity of the ipsilesional fronto-parietal network and higher fractional anisotropy of the ipsilesional rostral superior longitudinal fasciculus. CONCLUSIONS Stroke survivors with extensive CST damage have greater resting state functional connectivity of an ipsilesional fronto-parietal network that appears to be a behaviorally relevant neural mechanism that improves upper-limb motor performance.
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Affiliation(s)
- Brenton Hordacre
- University of South Australia, IIMPACT in Health, Adelaide, Australia.
| | - Martín Lotze
- Functional Imaging Unit, Center for Diagnostic Radiology, University Medicine Greifswald, Greifswald, Germany
| | - Mark Jenkinson
- Wellcome Centre for Integrative Neuroimaging, Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Alberto Lazari
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Christen D Barras
- South Australian Health and Medical Research Institute, Adelaide, Australia; The University of Adelaide, Adelaide, Australia
| | - Lara Boyd
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Susan Hillier
- University of South Australia, IIMPACT in Health, Adelaide, Australia
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19
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Fok KL, Kaneko N, Sasaki A, Nakagawa K, Nakazawa K, Masani K. Motor Point Stimulation in Spinal Paired Associative Stimulation can Facilitate Spinal Cord Excitability. Front Hum Neurosci 2020; 14:593806. [PMID: 33328940 PMCID: PMC7729006 DOI: 10.3389/fnhum.2020.593806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/19/2020] [Indexed: 11/13/2022] Open
Abstract
Paired associative stimulation at the spinal cord (spinal PAS) has been shown to increase muscle force and dexterity by strengthening the corticomuscular connection, through spike timing dependent plasticity. Typically, transcranial magnetic stimulation (TMS) and transcutaneous peripheral nerve electrical stimulation (PNS) are often used in spinal PAS. PNS targets superficial nerve branches, by which the number of applicable muscles is limited. Alternatively, a muscle can be activated by positioning the stimulation electrode on the “motor point” (MPS), which is the most sensitive location of a muscle to electrical stimulation. Although this can increase the number of applicable muscles for spinal PAS, nobody has tested whether MPS can be used for the spinal PAS to date. Here we investigated the feasibility of using MPS instead of PNS for spinal PAS. Ten healthy male individuals (26.0 ± 3.5 yrs) received spinal PAS on two separate days with different stimulation timings expected to induce (1) facilitation of corticospinal excitability (REAL) or (2) no effect (CONTROL) on the soleus. The motor evoked potentials (MEP) response curve in the soleus was measured prior to the spinal PAS, immediately after (0 min) and at 10, 20, 30 min post-intervention as a measure of corticospinal excitability. The post-intervention MEP response curve areas were larger in the REAL condition than the CONTROL conditions. Further, the post-intervention MEP response curve areas were significantly larger than pre-intervention in the REAL condition but not in the CONTROL condition. We conclude that MPS can facilitate corticospinal excitability through spinal PAS.
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Affiliation(s)
- Kai Lon Fok
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Kite Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Naotsugu Kaneko
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Kite Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada.,Japan Society for the Promotion of Science, Tokyo, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Atsushi Sasaki
- Japan Society for the Promotion of Science, Tokyo, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Kento Nakagawa
- Kite Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada.,Japan Society for the Promotion of Science, Tokyo, Japan.,Faculty of Sport Sciences, Waseda University, Tokyo, Japan
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Kei Masani
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Kite Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
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20
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Sundman MH, Lim K, Ton That V, Mizell JM, Ugonna C, Rodriguez R, Chen NK, Fuglevand AJ, Liu Y, Wilson RC, Fellous JM, Rapcsak S, Chou YH. Transcranial magnetic stimulation reveals diminished homoeostatic metaplasticity in cognitively impaired adults. Brain Commun 2020; 2:fcaa203. [PMID: 33376989 PMCID: PMC7750948 DOI: 10.1093/braincomms/fcaa203] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 09/22/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Homoeostatic metaplasticity is a neuroprotective physiological feature that counterbalances Hebbian forms of plasticity to prevent network destabilization and hyperexcitability. Recent animal models highlight dysfunctional homoeostatic metaplasticity in the pathogenesis of Alzheimer's disease. However, the association between homoeostatic metaplasticity and cognitive status has not been systematically characterized in either demented or non-demented human populations, and the potential value of homoeostatic metaplasticity as an early biomarker of cognitive impairment has not been explored in humans. Here, we report that, through pre-conditioning the synaptic activity prior to non-invasive brain stimulation, the association between homoeostatic metaplasticity and cognitive status could be established in a population of non-demented human subjects (older adults across cognitive spectrums; all within the non-demented range). All participants (n = 40; age range, 65-74, 47.5% female) underwent a standardized neuropsychological battery, magnetic resonance imaging and a transcranial magnetic stimulation protocol. Specifically, we sampled motor-evoked potentials with an input/output curve immediately before and after repetitive transcranial magnetic stimulation to assess neural plasticity with two experimental paradigms: one with voluntary muscle contraction (i.e. modulated synaptic activity history) to deliberately introduce homoeostatic interference, and one without to serve as a control condition. From comparing neuroplastic responses across these experimental paradigms and across cohorts grouped by cognitive status, we found that (i) homoeostatic metaplasticity is diminished in our cohort of cognitively impaired older adults and (ii) this neuroprotective feature remains intact in cognitively normal participants. This novel finding suggests that (i) future studies should expand their scope beyond just Hebbian forms of plasticity that are traditionally assessed when using non-invasive brain stimulation to investigate cognitive ageing and (ii) the potential value of homoeostatic metaplasticity in serving as a biomarker for cognitive impairment should be further explored.
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Affiliation(s)
- Mark H Sundman
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
| | - Koeun Lim
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
| | - Viet Ton That
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
| | | | - Chidi Ugonna
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721, USA
- Department of Medical Imaging, University of Arizona, Tucson, AZ 85721, USA
| | - Rudolph Rodriguez
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
| | - Nan-Kuei Chen
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721, USA
- Department of Medical Imaging, University of Arizona, Tucson, AZ 85721, USA
| | - Andrew J Fuglevand
- Department of Physiology, College of Medicine, University of Arizona, Tucson, AZ 85721, USA
- Department of Neuroscience, College of Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - Yilin Liu
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
| | - Robert C Wilson
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
| | - Jean-Marc Fellous
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721, USA
| | - Steven Rapcsak
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
- Department of Neurology, University of Arizona, Tucson, AZ 85721, USA
| | - Ying-Hui Chou
- Department of Psychology, University of Arizona, Tucson, AZ 85721, USA
- Evelyn F. McKnight Brain Institute, Arizona Center on Aging, and BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA
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21
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Lin YL, Potter-Baker KA, Cunningham DA, Li M, Sankarasubramanian V, Lee J, Jones S, Sakaie K, Wang X, Machado AG, Plow EB. Stratifying chronic stroke patients based on the influence of contralesional motor cortices: An inter-hemispheric inhibition study. Clin Neurophysiol 2020; 131:2516-2525. [PMID: 32712080 DOI: 10.1016/j.clinph.2020.06.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 01/27/2023]
Abstract
OBJECTIVE A recent "bimodal-balance recovery" model suggests that contralesional influence varies based on the amount of ipsilesional reserve: inhibitory when there is a large reserve, but supportive when there is a low reserve. Here, we investigated the relationships between contralesional influence (inter-hemispheric inhibition, IHI) and ipsilesional reserve (corticospinal damage/impairment), and also defined a criterion separating subgroups based on the relationships. METHODS Twenty-four patients underwent assessment of IHI using Transcranial Magnetic Stimulation (ipsilateral silent period method), motor impairment using Upper Extremity Fugl-Meyer (UEFM), and corticospinal damage using Diffusion Tensor Imaging and active motor threshold. Assessments of UEFM and IHI were repeated after 5-week rehabilitation (n = 21). RESULTS Relationship between IHI and baseline UEFM was quadratic with criterion at UEFM 43 (95%conference interval: 40-46). Patients less impaired than UEFM = 43 showed stronger IHI with more impairment, whereas patients more impaired than UEFM = 43 showed lower IHI with more impairment. Of those made clinically-meaningful functional gains in rehabilitation (n = 14), more-impaired patients showed further IHI reduction. CONCLUSIONS A criterion impairment-level can be derived to stratify patient-subgroups based on the bimodal influence of contralesional cortex. Contralesional influence also evolves differently across subgroups following rehabilitation. SIGNIFICANCE The criterion may be used to stratify patients to design targeted, precision treatments.
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Affiliation(s)
- Yin-Liang Lin
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan
| | - Kelsey A Potter-Baker
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veteran's Affairs, Cleveland, OH, USA; Department of Health and Biomedical Sciences, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - David A Cunningham
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Physical Medicine and Rehabilitation, Case Western Reserve University, Cleveland, OH, USA; MetroHealth Rehabilitation Institute of Ohio, MetroHealth Medical Center, Cleveland, OH, USA; Cleveland Functional Electrical Stimulation Center, Louis Stokes Cleveland Department of Veteran's Affairs, Cleveland, OH, USA
| | - Manshi Li
- Respiratory Institute Biostatistics Core, Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Vishwanath Sankarasubramanian
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - John Lee
- Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic, OH, USA
| | - Stephen Jones
- Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ken Sakaie
- Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaofeng Wang
- Respiratory Institute Biostatistics Core, Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Ela B Plow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic, OH, USA.
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22
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Chaves AR, Devasahayam AJ, Riemenschneider M, Pretty RW, Ploughman M. Walking Training Enhances Corticospinal Excitability in Progressive Multiple Sclerosis-A Pilot Study. Front Neurol 2020; 11:422. [PMID: 32581998 PMCID: PMC7287174 DOI: 10.3389/fneur.2020.00422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/22/2020] [Indexed: 12/16/2022] Open
Abstract
Background: Inflammatory lesions and neurodegeneration lead to motor, cognitive, and sensory impairments in people with multiple sclerosis (MS). Accumulation of disability is at least partially due to diminished capacity for neuroplasticity within the central nervous system. Aerobic exercise is a potentially important intervention to enhance neuroplasticity since it causes upregulation of neurotrophins and enhances corticospinal excitability, which can be probed using single-pulse transcranial magnetic stimulation (TMS). Whether people with progressive MS who have accumulated substantial disability could benefit from walking rehabilitative training to enhance neuroplasticity is not known. Objective: We aimed to determine whether 10 weeks of task-specific walking training would affect corticospinal excitability over time (pre, post, and 3-month follow-up) among people with progressive MS who required walking aids. Results: Eight people with progressive MS (seven female; 29–74 years old) with an Expanded Disability Status Scale of 6–6.5 underwent harness-supported treadmill walking training in a temperature controlled room at 16°C (10 weeks; three times/week; 40 min at 40–65% heart rate reserve). After training, there was significantly higher corticospinal excitability in both brain hemispheres, reductions in TMS active motor thresholds, and increases in motor-evoked potential amplitudes and slope of the recruitment curve (REC). Decreased intracortical inhibition (shorter cortical silent period) after training was noted in the hemisphere corresponding to the stronger hand only. These effects were not sustained at follow-up. There was a significant relationship between increases in corticospinal excitability (REC, area under the curve) in the hemisphere corresponding to the stronger hand and lessening of both intensity and impact of fatigue on activities of daily living (Fatigue Severity Scale and Modified Fatigue Impact Scale, respectively). Conclusion: Our pilot results support that vigorous treadmill training can potentially improve neuroplastic potential and mitigate symptoms of the disease even among people who have accumulated substantial disability due to MS.
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Affiliation(s)
- Arthur R Chaves
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Augustine J Devasahayam
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Morten Riemenschneider
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Ryan W Pretty
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Michelle Ploughman
- Recovery and Performance Laboratory, Faculty of Medicine, L. A. Miller Centre, Memorial University of Newfoundland, St. John's, NL, Canada
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23
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Exercise-Induced Brain Excitability Changes in Progressive Multiple Sclerosis: A Pilot Study. J Neurol Phys Ther 2020; 44:132-144. [DOI: 10.1097/npt.0000000000000308] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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24
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Iyer PC, Madhavan S. Characterization of stimulus response curves obtained with transcranial magnetic stimulation from bilateral tibialis anterior muscles post stroke. Neurosci Lett 2019; 713:134530. [PMID: 31585209 PMCID: PMC7226675 DOI: 10.1016/j.neulet.2019.134530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Stimulus response curves (SR curves), measured using transcranial magnetic stimulation (TMS) induced motor evoked potentials (MEP), yield important information regarding corticomotor connectivity. Limited understanding of SR curve analyses techniques for leg muscles after stroke may limit the utility of TMS data for walking recovery. OBJECTIVE To compare linear and non-linear curve fitting for MEP responses from the non-paretic and paretic tibialis anterior (TA) muscles. METHODS Accuracy of fit was measured using coefficient of determination (R2). Similarities of the fit were compared using slopes and area under the curve (AUC). RESULTS The non-linear function demonstrated higher R2 and slopes. The AUC was not significantly different between the two analyses approaches. The non-linear non-paretic SR slopes and paretic AUC had significant associations with walking speed. CONCLUSION Our results highlight the differences between non-linear and linear approaches to best fit the SR curves from bilateral TA muscles in stroke survivors. Although the linear function can appropriately fit the SR curve of the paretic and non-paretic TA, the non-linear function estimated a higher slope. We found the AUC to be a more robust measure that was not affected by the type of curve-fitting approach and only the AUC of the paretic TA showed significant association with walking speeds. A better understanding of SR curve fitting approaches for the TA muscles in individuals with chronic stroke allows for their optimal use in interpretation of TMS data and literature.
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Affiliation(s)
- Pooja C Iyer
- Graduate Program in Rehabilitation Science, College of Applied Health Sciences, University of Illinois, Chicago, IL, USA
| | - Sangeetha Madhavan
- Brain Plasticity Laboratory, Department of Physical Therapy, College of Applied Health Sciences, University of Illinois, Chicago, IL, USA.
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25
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Kemlin C, Moulton E, Leder S, Houot M, Meunier S, Rosso C, Lamy JC. Redundancy Among Parameters Describing the Input-Output Relation of Motor Evoked Potentials in Healthy Subjects and Stroke Patients. Front Neurol 2019; 10:535. [PMID: 31178817 PMCID: PMC6537607 DOI: 10.3389/fneur.2019.00535] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/03/2019] [Indexed: 12/13/2022] Open
Abstract
Background: Transcranial magnetic stimulation (TMS) is widely used to probe corticospinal excitability through Motor Evoked Potential (MEP) amplitude measurements. The input-output (I/O) curve is a sigmoid-shaped relation between the MEP amplitude at incremented TMS intensities. The aim of this study was to examine the relationships between seven parameters derived from the sigmoid function. Methods: Principal Component Analysis and Spearman's rank correlation matrices were used to determine if the seven I/O curve parameters capture similar or, conversely, different aspects of the corticospinal excitability in 24 healthy subjects and 40 stroke survivors with a hand motor impairment. Results: Maximum amplitude (MEPmax), peak slope, area under the I/O curve (AUC), and MEP amplitude recorded at 140% of the resting motor threshold showed strong linear relationships with each other (ρ > 0.72, p < 0.001). Results were found to be similar in healthy subjects and in both hemispheres of stroke patients. Our results did not support an added benefit of sampling entire I/O curves in both healthy subjects and stroke patients, with the exception of S50, the stimulus intensity needed to obtain half of MEPmax amplitude. Conclusions: This demonstrates that MEP elicited at a single stimulus intensity allows to capture the same characteristics of the corticospinal excitability as measured by the AUC, MEPmax and the peak slope, which may be of interest in both clinical and research settings. However, it is still necessary to plot I/O curves if an effect or a difference is expected at S50.
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Affiliation(s)
- Claire Kemlin
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Eric Moulton
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Sara Leder
- APHP, Urgences Cérébro-Vasculaires, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Marion Houot
- AP-HP, Department of Neurology, Hôpital de la Pitié-Salpêtrière, Centre of excellence of neurodegenerative disease (CoEN), Institute of Memory and Alzheimer's Disease (IM2A), ICM, CIC Neurosciences, Paris, France
| | - Sabine Meunier
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Charlotte Rosso
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France.,APHP, Urgences Cérébro-Vasculaires, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Jean-Charles Lamy
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
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26
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Archer DB, Vaillancourt DE, Coombes SA. A Template and Probabilistic Atlas of the Human Sensorimotor Tracts using Diffusion MRI. Cereb Cortex 2018; 28:1685-1699. [PMID: 28334314 PMCID: PMC5907352 DOI: 10.1093/cercor/bhx066] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/27/2017] [Accepted: 02/28/2017] [Indexed: 12/26/2022] Open
Abstract
The purpose of this study was to develop a high-resolution sensorimotor area tract template (SMATT) which segments corticofugal tracts based on 6 cortical regions in primary motor cortex, dorsal premotor cortex, ventral premotor cortex, supplementary motor area (SMA), pre-supplementary motor area (preSMA), and primary somatosensory cortex using diffusion tensor imaging. Individual probabilistic tractography analyses were conducted in 100 subjects using the highest resolution data currently available. Tractography results were refined using a novel algorithm to objectively determine slice level thresholds that best minimized overlap between tracts while preserving tract volume. Consistent with tracing studies in monkey and rodent, our observations show that cortical topography is generally preserved through the internal capsule, with the preSMA tract remaining most anterior and the primary somatosensory tract remaining most posterior. We combine our results into a freely available white matter template named the SMATT. We also provide a probabilistic SMATT that quantifies the extent of overlap between tracts. Finally, we assess how the SMATT operates at the individual subject level in another independent data set, and in an individual after stroke. The SMATT and probabilistic SMATT provide new tools that segment and label sensorimotor tracts at a spatial resolution not previously available.
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Affiliation(s)
- Derek B Archer
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
| | - David E Vaillancourt
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL 32611, USA
- Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Stephen A Coombes
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA
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27
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Sankarasubramanian V, Machado AG, Conforto AB, Potter-Baker KA, Cunningham DA, Varnerin NM, Wang X, Sakaie K, Plow EB. Inhibition versus facilitation of contralesional motor cortices in stroke: Deriving a model to tailor brain stimulation. Clin Neurophysiol 2017; 128:892-902. [PMID: 28402865 DOI: 10.1016/j.clinph.2017.03.030] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 03/08/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The standard approach to brain stimulation in stroke is based on the premise that ipsilesional M1 (iM1) is important for motor function of the paretic upper limb, while contralesional cortices compete with iM1. Therefore, the approach typically advocates facilitating iM1 and/or inhibiting contralesional M1 (cM1). But, this approach fails to elicit much improvement in severely affected patients, who on account of extensive damage to ipsilesional pathways, cannot rely on iM1. These patients are believed to instead rely on the undamaged cortices, especially the contralesional dorsal premotor cortex (cPMd), for support of function of the paretic limb. Here, we tested for the first time whether facilitation of cPMd could improve paretic limb function in severely affected patients, and if a cut-off could be identified to separate responders to cPMd from responders to the standard approach to stimulation. METHODS In a randomized, sham-controlled crossover study, fifteen patients received the standard approach of stimulation involving inhibition of cM1 and a new approach involving facilitation of cPMd using repetitive transcranial magnetic stimulation (rTMS). Patients also received rTMS to control areas. At baseline, impairment [Upper Extremity Fugl-Meyer (UEFMPROXIMAL, max=36)] and damage to pathways [fractional anisotropy (FA)] was measured. We measured changes in time to perform proximal paretic limb reaching, and neurophysiology using TMS. RESULTS Facilitation of cPMd generated more improvement in severely affected patients, who had experienced greater damage and impairment than a cut-off value of FA (0.5) and UEFMPROXIMAL (26-28). The standard approach instead generated more improvement in mildly affected patients. Responders to cPMd showed alleviation of interhemispheric competition imposed on iM1, while responders to the standard approach showed gains in ipsilesional excitability in association with improvement. CONCLUSIONS A preliminary cut-off level of severity separated responders for standard approach vs. facilitation of cPMd. SIGNIFICANCE Cut-offs identified here could help select candidates for tailored stimulation in future studies so patients in all ranges of severity could potentially achieve maximum benefit in function of the paretic upper limb.
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Affiliation(s)
| | - Andre G Machado
- Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Adriana B Conforto
- Neurology Clinical Division, Neurology Department, Hospital das Clinicas, São Paulo University, 05508-090 São Paulo, SP, Brazil; Hospital Israelita Albert Einstein, 05652-900 São Paulo, SP, Brazil
| | - Kelsey A Potter-Baker
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - David A Cunningham
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Nicole M Varnerin
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Xiaofeng Wang
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Ken Sakaie
- Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Ela B Plow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA; Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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28
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Ipsilesional High Frequency Repetitive Transcranial Magnetic Stimulation Add-On Therapy Improved Diffusion Parameters of Stroke Patients with Motor Dysfunction: A Preliminary DTI Study. Neural Plast 2016; 2016:6238575. [PMID: 27840742 PMCID: PMC5093297 DOI: 10.1155/2016/6238575] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/31/2016] [Indexed: 12/22/2022] Open
Abstract
Purpose. The aim of this study was to evaluate the effects of high frequency repetitive transcranial magnetic stimulation (HF-rTMS) on stroke patients with motor dysfunction and to investigate the underlying neural mechanism. Methods. Fifteen stroke patients were assigned to the rTMS treatment (RT) group and conventional treatment (CT) group. Patients in the RT received 10 Hz rTMS stimulation on the ipsilesional primary motor cortex for 10 days plus conventional treatment of CT, which consisted of acupuncture and antiplatelet aggregation medication. Difference in fractional anisotropy (FA) between pretreatment and posttreatment and between two groups was determined. Correlations between FA values and neurological assessments were also calculated. Results. Both groups significantly improved the neurological function after treatment. rTMS-treated patients showed better improvement in Fugl-Meyer Assessment (FMA) score and increased FA value in motor-related white matter and gray matter cortices compared with CT-treated patients and pretreatment status. Besides, the increased FA value in the ipsilesional posterior limb of the internal capsule in RT group was significantly correlated with the improved FMA score. Significance. HF-rTMS could be a supplement therapy to CT in improving motor recovery in patients with stroke. And this benefit effect may be achieved through modulating the ipsilesional corticospinal tracts and motor-related gray matter cortices.
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