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Onyiriuka L, Aliaga-Arias JM, Patel S, Khan A, Ashkan K, Gullan R, Bhangoo R, Ahmed A, Grahovac G, Vergani F, Kailaya-Vasan A, Lavrador JP. Identifying functional cortical plasticity after spinal tumour resection using navigated transcranial magnetic stimulation. Ann R Coll Surg Engl 2024. [PMID: 38961733 DOI: 10.1308/rcsann.2024.0040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024] Open
Abstract
Our aim was to investigate the effectiveness of navigated transcranial magnetic stimulation (nTMS) brain mapping to characterise preoperative motor impairment caused by an intradural extramedullary (IDEM) tumour and postoperative cortical functional reorganisation. Preoperative and 1-year follow-up clinical, radiological and nTMS data from a case of thoracic spinal meningioma that underwent surgical resection of the lesion were collected and compared. A 67-year-old patient presented with severe progressive thoracic myelopathy (hypertonic paraparesis, clonus, insensate urinary retention) secondary to an IDEM tumour. Initial nTMS assessment showed bilateral upper limb representation with no positive responses for both lower limbs. He underwent successful surgical resection for his IDEM (meningioma WHO grade 1). At 1-year follow-up, the patient's gait was improved and his bladder function normalised. nTMS documented positive responses for both upper and lower limbs and a decrease in the area (right side: 1.01 vs 0.39cm2; left side: 1.92 vs 0.81cm2) and volume (right side: 344.2 vs 42.4uVcm2; left side: 467.1 vs 119uVcm2) of cortical activation for both upper limbs, suggesting a functional reorganisation of the motor areas after tumour resection. nTMS motor mapping and derived metrics can characterise preoperative motor deficit and cortical plasticity during follow-up after IDEM resection.
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Affiliation(s)
- L Onyiriuka
- King's College Hospital NHS Foundation Trust, UK
| | - J M Aliaga-Arias
- King's College Hospital NHS Foundation Trust, UK
- University of Brescia, Italy
| | - S Patel
- King's College Hospital NHS Foundation Trust, UK
- King's College London, UK
| | - A Khan
- King's College Hospital NHS Foundation Trust, UK
| | - K Ashkan
- King's College Hospital NHS Foundation Trust, UK
- King's College London, UK
| | - R Gullan
- King's College Hospital NHS Foundation Trust, UK
| | - R Bhangoo
- King's College Hospital NHS Foundation Trust, UK
| | - A Ahmed
- King's College Hospital NHS Foundation Trust, UK
- King's College London, UK
| | - G Grahovac
- King's College Hospital NHS Foundation Trust, UK
| | - F Vergani
- King's College Hospital NHS Foundation Trust, UK
| | - A Kailaya-Vasan
- King's College Hospital NHS Foundation Trust, UK
- King's College London, UK
| | - J P Lavrador
- King's College Hospital NHS Foundation Trust, UK
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Debenham MIB, Franz CK, Berger MJ. Neuromuscular consequences of spinal cord injury: New mechanistic insights and clinical considerations. Muscle Nerve 2024; 70:12-27. [PMID: 38477416 DOI: 10.1002/mus.28070] [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: 10/20/2023] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024]
Abstract
The spinal cord facilitates communication between the brain and the body, containing intrinsic systems that work with lower motor neurons (LMNs) to manage movement. Spinal cord injuries (SCIs) can lead to partial paralysis and dysfunctions in muscles below the injury. While traditionally this paralysis has been attributed to disruptions in the corticospinal tract, a growing body of work demonstrates LMN damage is a factor. Motor units, comprising the LMN and the muscle fibers with which they connect, are essential for voluntary movement. Our understanding of their changes post-SCI is still emerging, but the health of motor units is vital, especially when considering innovative SCI treatments like nerve transfer surgery. This review seeks to collate current literature on how SCI impact motor units and explore neuromuscular clinical implications and treatment avenues. SCI reduced motor unit number estimates, and surviving motor units had impaired signal transmission at the neuromuscular junction, force-generating capacity, and excitability, which have the potential to recover chronically, yet the underlaying mechanisms are unclear. Furthermore, electrodiagnostic evaluations can aid in assessing the health lower and upper motor neurons, identify suitable targets for nerve transfer surgeries, and detect patients with time sensitive injuries. Lastly, many electrodiagnostic abnormalities occur in both chronic and acute SCI, yet factors contributing to these abnormalities are unknown. Future studies are required to determine how motor units adapt following SCI and the clinical implications of these adaptations.
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Affiliation(s)
- Mathew I B Debenham
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin K Franz
- Biologics Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Arora T, Liu J, Mohan A, Li X, O'laughlin K, Bennett T, Nemunaitis G, Bethoux F, Pundik S, Forrest G, Kirshblum S, Kilgore K, Bryden A, Kristi Henzel M, Wang X, Baker K, Brihmat N, Bayram M, Plow EB. Corticospinal inhibition investigated in relation to upper extremity motor function in cervical spinal cord injury. Clin Neurophysiol 2024; 161:188-197. [PMID: 38520799 DOI: 10.1016/j.clinph.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 12/29/2023] [Accepted: 02/22/2024] [Indexed: 03/25/2024]
Abstract
OBJECTIVE Corticospinal inhibitory mechanisms are relevant to functional recovery but remain poorly understood after spinal cord injury (SCI). Post-injury characteristics of contralateral silent period (CSP), a measure of corticospinal inhibition evaluated using transcranial magnetic stimulation (TMS), is inconsistent in literature. We envisioned that investigating CSP across muscles with varying degrees of weakness may be a reasonable approach to resolve inconsistencies and elucidate the relevance of corticospinal inhibition for upper extremity function following SCI. METHODS We studied 27 adults with chronic C1-C8 SCI (age 48.8 ± 16.1 years, 3 females) and 16 able-bodied participants (age 33.2 ± 11.8 years, 9 females). CSP characteristics were assessed across biceps (muscle power = 3-5) and triceps (muscle power = 1-3) representing stronger and weaker muscles, respectively. We assessed functional abilities using the Capabilities of the Upper Extremity Test (CUE-T). RESULTS Participants with chronic SCI had prolonged CSPs for biceps but delayed and diminished CSPs for triceps compared to able-bodied participants. Early-onset CSPs for biceps and longer, deeper CSPs for triceps correlated with better CUE-T scores. CONCLUSIONS Corticospinal inhibition is pronounced for stronger biceps but diminished for weaker triceps muscle in SCI indicating innervation relative to the level of injury matters in the study of CSP. SIGNIFICANCE Nevertheless, corticospinal inhibition or CSP holds relevance for upper extremity function following SCI.
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Affiliation(s)
- Tarun Arora
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA; Department of Neurology, Division of Clinical Neuroscience, Oslo University Hospital, Norway
| | - Jia Liu
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA
| | - Akhil Mohan
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA
| | - Xin Li
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA
| | - Kyle O'laughlin
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA
| | - Teale Bennett
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA
| | - Gregory Nemunaitis
- Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic Foundation, OH, USA
| | - Francois Bethoux
- Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic Foundation, OH, USA
| | - Svetlana Pundik
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Ohio, USA; Department of Neurology, Case Western Reserve University School of Medicine, Cleveland OH, USA
| | - Gail Forrest
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA; Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA
| | - Steven Kirshblum
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA; Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA; Kessler Institute for Rehabilitation, West Orange, New Jersey, USA; Kessler Foundation, West Orange, New Jersey, USA
| | - Kevin Kilgore
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Ohio, USA; Department of Physical Medicine and Rehabilitation, MetroHealth Center for Rehabilitation Research, OH, USA; Institute for Functional Restoration, Case Western Reserve University, Cleveland, OH, USA
| | - Anne Bryden
- Department of Physical Medicine and Rehabilitation, MetroHealth Center for Rehabilitation Research, OH, USA; Institute for Functional Restoration, Case Western Reserve University, Cleveland, OH, USA
| | - M Kristi Henzel
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Ohio, USA; Department of Physical Medicine and Rehabilitation, Case Western Reserve University School of Medicine, Cleveland OH, USA
| | - Xiaofeng Wang
- Department of Quantitative Health Sciences, Cleveland Clinic Foundation, OH, USA
| | - Kelsey Baker
- Department of Neuroscience, School of Medicine, University of Texas RioGrande Valley, RioGrande Valley, TX, USA
| | - Nabila Brihmat
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA; Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA
| | - Mehmed Bayram
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA; Tim and Caroline Reynolds Center for Spinal Stimulation, Kessler Foundation, West Orange, New Jersey, USA
| | - Ela B Plow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, OH, USA; Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic Foundation, OH, USA; Cleveland Clinic Rehabilitation Hospitals, Cleveland, OH, USA.
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Kesikburun S, Uran Şan A, Yaşar E, Yılmaz B. The effect of high-frequency repetitive transcranial magnetic stimulation on motor recovery and gait parameters in chronic incomplete spinal cord injury: A randomized-controlled study. Turk J Phys Med Rehabil 2023; 69:275-285. [PMID: 37674795 PMCID: PMC10478546 DOI: 10.5606/tftrd.2023.11585] [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: 08/23/2022] [Accepted: 12/21/2022] [Indexed: 09/08/2023] Open
Abstract
Objectives This study aims to examine the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) on gait parameters and lower extremity motor recovery in a more specific sample of individuals with chronic and traumatic incomplete spinal cord injury (iSCI). Patients and methods This double-blind, sham-controlled, randomized study included a total of 28 individuals (20 males, 8 females; mean age: 35.7±12.1 years; range, 18 to 45 years) with chronic (>1 year) traumatic iSCI. The participants were randomly allocated to either sham rTMS group (n=14) or real rTMS group (n=14). We compared the groups based on the lower extremity motor scores (LEMS), the temporal-spatial gait measurements using three-dimensional gait analysis, the Walking Index for SCI-II (WISCI-II), and 10-m walking test at baseline, three weeks (post-treatment) and five weeks (follow-up) after the treatment. Results The real rTMS group revealed a significant improvement in walking speed, LEMS score, and 10-m walking test after the treatment compared to baseline (p=0.001, p=0.002, and p=0.023, respectively). Changes in the LEMS score were significantly increased in the real rTMS group compared to the sham group at both three and five weeks (p=0.001 and p=0.001, respectively). No significant difference was observed in the other variables between the groups (p>0.05). Conclusion Our study findings support the therapeutic effectiveness of rTMS on motor recovery in chronic iSCI. The rTMS can be used as an adjuvant therapy to conventional physiotherapy in the rehabilitation of patients with iSCI.
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Affiliation(s)
- Serdar Kesikburun
- Department of Physical Medicine and Rehabilitation, University of Health Sciences, Gülhane Medical School, Gaziler Physical Therapy and Rehabilitation Training and Research Hospital, Ankara, Türkiye
| | - Ayça Uran Şan
- Department of Physical Medicine and Rehabilitation, University of Health Sciences, Gaziler Physical Therapy and Rehabilitation Training and Research Hospital, Ankara, Türkiye
| | - Evren Yaşar
- Department of Physical Medicine and Rehabilitation, University of Health Sciences, Gülhane Medical School, Gaziler Physical Therapy and Rehabilitation Training and Research Hospital, Ankara, Türkiye
| | - Bilge Yılmaz
- Department of Physical Medicine and Rehabilitation, University of Health Sciences, Gülhane Medical School, Gaziler Physical Therapy and Rehabilitation Training and Research Hospital, Ankara, Türkiye
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Arora T, Desai N, Kirshblum S, Chen R. Utility of transcranial magnetic stimulation in the assessment of spinal cord injury: Current status and future directions. FRONTIERS IN REHABILITATION SCIENCES 2022; 3:1005111. [PMID: 36275924 PMCID: PMC9581184 DOI: 10.3389/fresc.2022.1005111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/16/2022] [Indexed: 11/06/2022]
Abstract
Comprehensive assessment following traumatic spinal cord injury (SCI) is needed to improve prognostication, advance the understanding of the neurophysiology and better targeting of clinical interventions. The International Standards for Neurological Classification of Spinal Cord Injury is the most common clinical examination recommended for use after a SCI. In addition, there are over 30 clinical assessment tools spanning across different domains of the International Classification of Functioning, Disability, and Health that have been validated and recommended for use in SCI. Most of these tools are subjective in nature, have limited value in predicting neurologic recovery, and do not provide insights into neurophysiological mechanisms. Transcranial magnetic stimulation (TMS) is a non-invasive neurophysiology technique that can supplement the clinical assessment in the domain of body structure and function during acute and chronic stages of SCI. TMS offers a better insight into neurophysiology and help in better detection of residual corticomotor connectivity following SCI compared to clinical assessment alone. TMS-based motor evoked potential and silent period duration allow study of excitatory and inhibitory mechanisms following SCI. Changes in muscle representations in form of displacement of TMS-based motor map center of gravity or changes in the map area can capture neuroplastic changes resulting from SCI or following rehabilitation. Paired-pulse TMS measures help understand the compensatory reorganization of the cortical circuits following SCI. In combination with peripheral stimulation, TMS can be used to study central motor conduction time and modulation of spinal reflexes, which can be used for advanced diagnostic and treatment purposes. To strengthen the utility of TMS in SCI assessment, future studies will need to standardize the assessment protocols, address population-specific concerns, and establish the psychometric properties of TMS-based measurements in the SCI population.
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Affiliation(s)
- Tarun Arora
- Krembil Research Institute, University Health Network, Toronto, ON, Canada,Correspondence: Tarun Arora Robert Chen
| | - Naaz Desai
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Steven Kirshblum
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, United States,Kessler Institute for Rehabilitation, West Orange, NJ, United States,Kessler Foundation, West Orange, NJ, United States,Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Robert Chen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada,Edmond J. Safra Program in Parkinson’s Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, ON, Canada,Division of Neurology, University of Toronto, Toronto, ON, Canada,Correspondence: Tarun Arora Robert Chen
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Chen B, Perez MA. Altered regulation of Ia afferent input during voluntary contraction in humans with spinal cord injury. eLife 2022; 11:e80089. [PMID: 36069767 PMCID: PMC9451536 DOI: 10.7554/elife.80089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Sensory input converging on the spinal cord contributes to the control of movement. Although sensory pathways reorganize following spinal cord injury (SCI), the extent to which sensory input from Ia afferents is regulated during voluntary contraction after the injury remains largely unknown. To address this question, the soleus H-reflex and conditioning of the H-reflex by stimulating homonymous [depression of the soleus H-reflex evoked by common peroneal nerve (CPN) stimulation, D1 inhibition] and heteronymous (d), [monosynaptic Ia facilitation of the soleus H-reflex evoked by femoral nerve stimulation (FN facilitation)] nerves were tested at rest, and during tonic voluntary contraction in humans with and without chronic incomplete SCI. The soleus H-reflex size increased in both groups during voluntary contraction compared with rest, but to a lesser extent in SCI participants. Compared with rest, the D1 inhibition decreased during voluntary contraction in controls but it was still present in SCI participants. Further, the FN facilitation increased in controls but remained unchanged in SCI participants during voluntary contraction compared with rest. Changes in the D1 inhibition and FN facilitation were correlated with changes in the H-reflex during voluntary contraction, suggesting an association between outcomes. These findings provide the first demonstration that the regulation of Ia afferent input from homonymous and heteronymous nerves is altered during voluntary contraction in humans with SCI, resulting in lesser facilitatory effect on motor neurons.
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Affiliation(s)
- Bing Chen
- Shirley Ryan AbilityLab, Northwestern University, and Edward Hines Jr., VA Medical CenterChicagoUnited States
| | - Monica A Perez
- Shirley Ryan AbilityLab, Northwestern University, and Edward Hines Jr., VA Medical CenterChicagoUnited States
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Tung KTS, Wong RS, Ho FK, Chan KL, Wong WHS, Leung H, Leung M, Leung GKK, Chow CB, Ip P. Development and Validation of Indicators for Population Injury Surveillance in Hong Kong: Development and Usability Study. JMIR Public Health Surveill 2022; 8:e36861. [PMID: 35980728 PMCID: PMC9437780 DOI: 10.2196/36861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/26/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Injury is an increasingly pressing global health issue. An effective surveillance system is required to monitor the trends and burden of injuries. OBJECTIVE This study aimed to identify a set of valid and context-specific injury indicators to facilitate the establishment of an injury surveillance program in Hong Kong. METHODS This development of indicators adopted a multiphased modified Delphi research design. A literature search was conducted on academic databases using injury-related search terms in various combinations. A list of potential indicators was sent to a panel of experts from various backgrounds to rate the validity and context-specificity of these indicators. Local hospital data on the selected core indicators were used to examine their applicability in the context of Hong Kong. RESULTS We reviewed 142 articles and identified 55 indicators, which were classified into 4 domains. On the basis of the ratings by the expert panel, 13 indicators were selected as core indicators because of their good validity and high relevance to the local context. Among these indicators, 10 were from the construct of health care service use, and 3 were from the construct of postdischarge outcomes. Regression analyses of local hospitalization data showed that the Hong Kong Safe Community certification status had no association with 5 core indicators (admission to intensive care unit, mortality rate, length of intensive care unit stay, need for a rehabilitation facility, and long-term behavioral and emotional outcomes), negative associations with 4 core indicators (operative intervention, infection rate, length of hospitalization, and disability-adjusted life years), and positive associations with the remaining 4 core indicators (attendance to accident and emergency department, discharge rate, suicide rate, and hospitalization rate after attending the accident and emergency department). These results confirmed the validity of the selected core indicators for the quantification of injury burden and evaluation of injury-related services, although some indicators may better measure the consequences of severe injuries. CONCLUSIONS This study developed a set of injury outcome indicators that would be useful for monitoring injury trends and burdens in Hong Kong.
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Affiliation(s)
- Keith T S Tung
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Rosa S Wong
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Frederick K Ho
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom
| | - Ko Ling Chan
- Department of Applied Social Sciences, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - Wilfred H S Wong
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Hugo Leung
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Ming Leung
- Accident and Emergency Department, Princess Margaret Hospital, Hong Kong, Hong Kong
| | - Gilberto K K Leung
- Department of Surgery, The University of Hong Kong, Hong Kong, Hong Kong
| | - Chun Bong Chow
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Patrick Ip
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong
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Benedetti B, Weidenhammer A, Reisinger M, Couillard-Despres S. Spinal Cord Injury and Loss of Cortical Inhibition. Int J Mol Sci 2022; 23:5622. [PMID: 35628434 PMCID: PMC9144195 DOI: 10.3390/ijms23105622] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023] Open
Abstract
After spinal cord injury (SCI), the destruction of spinal parenchyma causes permanent deficits in motor functions, which correlates with the severity and location of the lesion. Despite being disconnected from their targets, most cortical motor neurons survive the acute phase of SCI, and these neurons can therefore be a resource for functional recovery, provided that they are properly reconnected and retuned to a physiological state. However, inappropriate re-integration of cortical neurons or aberrant activity of corticospinal networks may worsen the long-term outcomes of SCI. In this review, we revisit recent studies addressing the relation between cortical disinhibition and functional recovery after SCI. Evidence suggests that cortical disinhibition can be either beneficial or detrimental in a context-dependent manner. A careful examination of clinical data helps to resolve apparent paradoxes and explain the heterogeneity of treatment outcomes. Additionally, evidence gained from SCI animal models indicates probable mechanisms mediating cortical disinhibition. Understanding the mechanisms and dynamics of cortical disinhibition is a prerequisite to improve current interventions through targeted pharmacological and/or rehabilitative interventions following SCI.
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Affiliation(s)
- Bruno Benedetti
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Annika Weidenhammer
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Maximilian Reisinger
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Sebastien Couillard-Despres
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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Quantitative electrophysiological assessments as predictive markers of lower limb motor recovery after spinal cord injury: a pilot study with an adaptive trial design. Spinal Cord Ser Cases 2022; 8:26. [PMID: 35210402 PMCID: PMC8873458 DOI: 10.1038/s41394-022-00491-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 01/27/2022] [Accepted: 02/01/2022] [Indexed: 11/13/2022] Open
Abstract
Study design Observational, cohort study. Objectives (1) Determine the feasibility and relevance of assessing corticospinal, sensory, and spinal pathways early after traumatic spinal cord injury (SCI) in a rehabilitation setting. (2) Validate whether electrophysiological and magnetic resonance imaging (MRI) measures taken early after SCI could identify preserved neural pathways, which could then guide therapy. Setting Intensive functional rehabilitation hospital (IFR). Methods Five individuals with traumatic SCI and eight controls were recruited. The lower extremity motor score (LEMS), electrical perceptual threshold (EPT) at the S2 dermatome, soleus (SOL) H-reflex, and motor evoked potentials (MEPs) in the tibialis anterior (TA) muscle were assessed during the stay in IFR and in the chronic stage (>6 months post-SCI). Control participants were only assessed once. Feasibility criteria included the absence of adverse events, adequate experimental session duration, and complete dataset gathering. The relationship between electrophysiological data collected in IFR and LEMS in the chronic phase was studied. The admission MRI was used to calculate the maximal spinal cord compression (MSCC). Results No adverse events occurred, but a complete dataset could not be collected for all subjects due to set-up configuration limitations and time constraints. EPT measured at IFR correlated with LEMS in the chronic phases (r = −0.67), whereas SOL H/M ratio, H latency, MEPs and MSCC did not. Conclusions Adjustments are necessary to implement electrophysiological assessments in an IFR setting. Combining MRI and electrophysiological measures may lead to better assessment of neuronal deficits early after SCI.
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Chiou SY, Strutton PH. Crossed Corticospinal Facilitation Between Arm and Trunk Muscles Correlates With Trunk Control After Spinal Cord Injury. Front Hum Neurosci 2020; 14:583579. [PMID: 33192418 PMCID: PMC7645046 DOI: 10.3389/fnhum.2020.583579] [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: 07/22/2020] [Accepted: 09/22/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: To investigate whether crossed corticospinal facilitation between arm and trunk muscles is preserved following spinal cord injury (SCI) and to elucidate these neural interactions for postural control during functional arm movements. Methods: Using transcranial magnetic stimulation (TMS) in 22 subjects with incomplete SCI motor evoked potentials (MEPs) in the erector spinae (ES) muscle were examined when the contralateral arm was at rest or performed 20% of maximal voluntary contraction (MVC) of biceps brachii (BB) or triceps brachii (TB). Trunk function was assessed with rapid shoulder flexion and forward-reaching tasks. Results: MEP amplitudes in ES were increased during elbow flexion in some subjects and this facilitatory effect was more prominent in subjects with thoracic SCI than in the subjects with cervical SCI. Those who showed the increased MEPs during elbow flexion had faster reaction times and quicker anticipatory postural adjustments of the trunk in the rapid shoulder flexion task. The onset of EMG activity in ES during the rapid shoulder flexion task correlated with the trunk excursion in forward-reaching. Conclusions: Our findings demonstrate that crossed corticospinal facilitation in the trunk muscles can be preserved after SCI and is reflected in trunk control during functional arm movements.
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Affiliation(s)
- Shin-Yi Chiou
- Sport, Exercise, and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.,The Nick Davey Laboratory, Division of Surgery, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Paul H Strutton
- The Nick Davey Laboratory, Division of Surgery, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom
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Contribution of corticospinal drive to ankle plantar flexor muscle activation during gait in adults with cerebral palsy. Exp Brain Res 2019; 237:1457-1467. [PMID: 30900000 DOI: 10.1007/s00221-019-05520-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/13/2019] [Indexed: 01/02/2023]
Abstract
Impaired plantar flexor muscle activation during push-off in late stance contributes importantly to reduced gait ability in adults with cerebral palsy (CP). Here we used low-intensity transcranial magnetic stimulation (TMS) to suppress soleus EMG activity during push-off as an estimate of corticospinal drive in CP adults and neurologically intact (NI) adults. Ten CP adults (age 34 years, SD 14.6, GMFCS I-II) and ten NI adults (age 33 years, SD 9.8) walked on a treadmill at their preferred walking speed. TMS of the leg motor cortex was elicited just prior to push-off during gait at intensities below threshold for motor-evoked potentials. Soleus EMG from steps with and without TMS were averaged and compared. Control experiments were performed while standing and in NI adults during gait at slow speed. TMS induced a suppression at a latency of about 40 ms. This suppression was similar in the two populations when differences in control EMG and gait speed were taken into account (CP 18%, NI 16%). The threshold of the suppression was higher in CP adults. The findings suggest that corticospinal drive to ankle plantar flexors at push-off is comparable in CP and NI adults. The higher threshold of the suppression in CP adults may reflect downregulation of cortical inhibition to facilitate corticospinal drive. Interventions aiming to facilitate excitability in cortical networks may contribute to maintain or even improve efficient gait in CP adults.
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What is the functional relevance of reorganization in primary motor cortex after spinal cord injury? Neurobiol Dis 2019; 121:286-295. [DOI: 10.1016/j.nbd.2018.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 09/10/2018] [Indexed: 01/15/2023] Open
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Abstract
Spinal cord injury is associated with chronic sensorimotor deficits due to the interruption of ascending and descending tracts between the brain and spinal cord. Functional recovery after anatomically complete spinal cord injury is limited due to the lack of long-distance axonal regeneration of severed fibers in the adult central nervous system. Most spinal cord injuries in humans, however, are anatomically incomplete. Although restorative treatment options for spinal cord injury remain currently limited, research from experimental models of spinal cord injury have revealed a tremendous capability for both spontaneous and treatment-induced plasticity of the corticospinal system that supports functional recovery. We review recent advances in the understanding of corticospinal circuit plasticity after spinal cord injury and concentrate mainly on the hindlimb motor cortex, its corticospinal projections, and the role of spinal mechanisms that support locomotor recovery. First, we discuss plasticity that occurs at the level of motor cortex and the reorganization of cortical movement representations. Next, we explore downstream plasticity in corticospinal projections. We then review the role of spinal mechanisms in locomotor recovery. We conclude with a perspective on harnessing neuroplasticity with therapeutic interventions to promote functional recovery.
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Affiliation(s)
- Andrew R Brown
- Département de Neurosciences, Faculté de Médecine, Université de Montréal; Hôpital du Sacré-Coeur de Montréal (CIUSS-NIM), Montréal, Québec, Canada
| | - Marina Martinez
- Département de Neurosciences, Faculté de Médecine, Université de Montréal; Hôpital du Sacré-Coeur de Montréal (CIUSS-NIM), Montréal; Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
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Jutzeler CR, Streijger F, Aguilar J, Shortt K, Manouchehri N, Okon E, Hupp M, Curt A, Kwon BK, Kramer JLK. Sensorimotor plasticity after spinal cord injury: a longitudinal and translational study. Ann Clin Transl Neurol 2018; 6:68-82. [PMID: 30656185 PMCID: PMC6331953 DOI: 10.1002/acn3.679] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/12/2018] [Accepted: 10/03/2018] [Indexed: 11/06/2022] Open
Abstract
Objective The objective was to track and compare the progression of neuroplastic changes in a large animal model and humans with spinal cord injury. Methods A total of 37 individuals with acute traumatic spinal cord injury were followed over time (1, 3, 6, and 12 months post-injury) with repeated neurophysiological assessments. Somatosensory and motor evoked potentials were recorded in the upper extremities above the level of injury. In a reverse-translational approach, similar neurophysiological techniques were examined in a porcine model of thoracic spinal cord injury. Twelve Yucatan mini-pigs underwent a contusive spinal cord injury at T10 and tracked with somatosensory and motor evoked potentials assessments in the fore- and hind limbs pre- (baseline, post-laminectomy) and post-injury (10 min, 3 h, 12 weeks). Results In both humans and pigs, the sensory responses in the cranial coordinates of upper extremities/forelimbs progressively increased from immediately post-injury to later time points. Motor responses in the forelimbs increased immediately after experimental injury in pigs, remaining elevated at 12 weeks. In humans, motor evoked potentials were significantly higher at 1-month (and remained so at 1 year) compared to normative values. Conclusions Despite notable differences between experimental models and the human condition, the brain's response to spinal cord injury is remarkably similar between humans and pigs. Our findings further underscore the utility of this large animal model in translational spinal cord injury research.
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Affiliation(s)
- Catherine R Jutzeler
- Spinal Cord Injury Center University Hospital Balgrist University of Zurich Zurich Switzerland.,ICORD University of British Columbia Vancouver British Columbia Canada.,School of Kinesiology University of British Columbia Vancouver British Columbia Canada
| | - Femke Streijger
- ICORD University of British Columbia Vancouver British Columbia Canada
| | - Juan Aguilar
- Experimental Neurophysiology Group Hospital Nacional de Parapléjicos SESCAM Toledo Spain
| | - Katelyn Shortt
- ICORD University of British Columbia Vancouver British Columbia Canada
| | - Neda Manouchehri
- Spinal Cord Injury Center University Hospital Balgrist University of Zurich Zurich Switzerland
| | - Elena Okon
- Spinal Cord Injury Center University Hospital Balgrist University of Zurich Zurich Switzerland
| | - Markus Hupp
- Spinal Cord Injury Center University Hospital Balgrist University of Zurich Zurich Switzerland
| | - Armin Curt
- Spinal Cord Injury Center University Hospital Balgrist University of Zurich Zurich Switzerland.,European Multi-Centre Study about Spinal Cord Injury (EMSCI) Study Group University Hospital Balgrist University of Zurich Zurich 8008 Switzerland
| | - Brian K Kwon
- ICORD University of British Columbia Vancouver British Columbia Canada
| | - John L K Kramer
- ICORD University of British Columbia Vancouver British Columbia Canada.,School of Kinesiology University of British Columbia Vancouver British Columbia Canada
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Sato S, Kakuda W, Sano M, Kitahara T, Kiko R. Therapeutic Application of Transcranial Magnetic Stimulation Combined with Rehabilitative Training for Incomplete Spinal Cord Injury: A Case Report. Prog Rehabil Med 2018; 3:20180014. [PMID: 32789239 DOI: 10.2490/prm.20180014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/14/2018] [Indexed: 11/09/2022] Open
Abstract
Background Only a few researchers have therapeutically applied transcranial magnetic stimulation (TMS) for patients with spinal cord injury. The purpose of this case study was to evaluate the safety, feasibility, and efficacy of therapeutic TMS combined with rehabilitative training for a patient with tetraparesis resulting from incomplete spinal cord injury. Case An 82-year-old male patient with incomplete spinal cord injury was admitted to our department for long-term rehabilitation. Eighteen days prior to admission, the patient sustained the injury in a fall. At admission to our department, the patient was diagnosed as having injury of the spinal cord at the C6 level. From the 76th day after admission, when the patient was considered to have attained a plateau state of recovery, application of therapeutic TMS was initiated using a double-cone coil. Two 15-min sessions of 10-Hz TMS were scheduled for daily application. Simultaneously, rehabilitative training was continuously provided. This patient received a total of 30 sessions of TMS over 19 days. Neither adverse effects nor deterioration of neurological symptoms was recognized during the intervention period. With this application of TMS, some improvements were evident in the American Spinal Injury Association motor score, the knee muscle strength, and the calf circumference. Discussion This case study demonstrated the safety and feasibility of TMS combined with rehabilitative training in a patient with incomplete spinal cord injury. Our protocol featuring TMS might constitute a novel neurorehabilitation intervention for such patients; however, the efficacy of the protocol should be confirmed in a large number of patients.
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Affiliation(s)
- Shin Sato
- Department of Rehabilitation Medicine, International University of Health and Welfare Ichikawa Hospital, Ichikawa, Chiba, Japan
| | - Wataru Kakuda
- Department of Rehabilitation Medicine, School of Medicine, International University of Health and Welfare, Narita, Chiba, Japan
| | - Mitsuhiro Sano
- Department of Rehabilitation Medicine, International University of Health and Welfare Ichikawa Hospital, Ichikawa, Chiba, Japan
| | - Takamasa Kitahara
- Department of Rehabilitation Medicine, International University of Health and Welfare Ichikawa Hospital, Ichikawa, Chiba, Japan
| | - Risa Kiko
- Department of Rehabilitation Medicine, International University of Health and Welfare Ichikawa Hospital, Ichikawa, Chiba, Japan
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Federico P, Perez MA. Altered corticospinal function during movement preparation in humans with spinal cord injury. J Physiol 2016; 595:233-245. [PMID: 27485306 DOI: 10.1113/jp272266] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/25/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS In uninjured humans, transmission in the corticospinal pathway changes in a task-dependent manner during movement preparation. We investigated whether this ability is preserved in humans with incomplete chronic cervical spinal cord injury (SCI). Our results show that corticospinal excitability is altered in the preparatory phase of an upcoming movement when there is a need to suppress but not to execute rapid index finger voluntary contractions in individuals with SCI compared with controls. This is probably related to impaired transmission at a cortical and spinal level after SCI. Overall our findings indicate that deficits in corticospinal transmission in humans with chronic incomplete SCI are also present in the preparatory phase of upcoming movements. ABSTRACT Corticospinal output is modulated in a task-dependent manner during the preparatory phase of upcoming movements in humans. Whether this ability is preserved after spinal cord injury (SCI) is unknown. In this study, we examined motor evoked potentials elicited by cortical (MEPs) and subcortical (CMEPs) stimulation of corticospinal axons and short-interval intracortical inhibition in the first dorsal interosseous muscle in the preparatory phase of a reaction time task where individuals with chronic incomplete cervical SCI and age-matched controls needed to suppress (NOGO) or initiate (GO) ballistic index finger isometric voluntary contractions. Reaction times were prolonged in SCI participants compared with control subjects and stimulation was provided ∼90 ms prior to movement onset in each group. During NOGO trials, both MEPs and CMEPs remained unchanged compared to baseline in SCI participants but were suppressed in control subjects. Notably, during GO trials, MEPs increased to a similar extent in both groups but CMEPs increased only in controls. The magnitude of short-interval intracortical inhibition increased in controls but not in SCI subjects during NOGO trials and decreased in both groups in GO trials. These novel observations reveal that humans with incomplete cervical SCI have an altered ability to modulate corticospinal excitability during movement preparation when there is a need to suppress but not to execute upcoming rapid finger movements, which is probably related to impaired transmission at a cortical and spinal level. Thus, deficits in corticospinal transmission after human SCI extend to the preparatory phase of upcoming movements.
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Affiliation(s)
- Paolo Federico
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami, Miami, FL, USA
| | - Monica A Perez
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami, Miami, FL, USA
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Reliability of TMS metrics in patients with chronic incomplete spinal cord injury. Spinal Cord 2016; 54:980-990. [DOI: 10.1038/sc.2016.47] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 02/18/2016] [Accepted: 02/28/2016] [Indexed: 12/26/2022]
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Affiliation(s)
- Nardone Raffaele
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Merano, Italy; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
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Huang Q, Zhou Y, Yu L, Gu R, Cui Y, Hu C. The reliability of evaluation of hip muscle strength in rehabilitation robot walking training. J Phys Ther Sci 2015; 27:3073-5. [PMID: 26644646 PMCID: PMC4668137 DOI: 10.1589/jpts.27.3073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/06/2015] [Indexed: 11/24/2022] Open
Abstract
[Purpose] The primary purpose of this study was to evaluate the intraclass correlation coefficient in obtaining the torque of the hip muscle strength during a robot-assisted rehabilitation treatment. [Subjects] Twenty-four patients (15 males, 9 females) with spinal cord injury participated in the study. [Methods] The subjects were asked to walk during robot-assisted rehabilitation, and the torque of the muscle strength which was measured at hip joint flexion angles of -15, -10, -5, 0, 5, 10, 15, 20, 25, and 30 degrees. [Results] The intraclass correlation coefficient of the torque of the hip muscle strength measured by the rehabilitation training robot was excellent. [Conclusion] Our results show that measurement of torque can be used as an objective assessment of treatment with RAT.
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Affiliation(s)
- Qiuchen Huang
- School of Rehabilitation Medicine, Capital Medical University, China ; Department of Physical Therapy, China Rehabilitation Research Center, China
| | - Yue Zhou
- School of Rehabilitation Medicine, Capital Medical University, China ; Department of Physical Therapy, China Rehabilitation Research Center, China
| | - Lili Yu
- School of Rehabilitation Medicine, Capital Medical University, China ; Department of Physical Therapy, China Rehabilitation Research Center, China
| | - Rui Gu
- School of Rehabilitation Medicine, Capital Medical University, China ; Department of Orthopedic and Orthopedic Rehabilitation, China Rehabilitation Research Center, China
| | - Yao Cui
- School of Rehabilitation Medicine, Capital Medical University, China ; Department of Physical Therapy, China Rehabilitation Research Center, China
| | - Chunying Hu
- School of Rehabilitation Medicine, Capital Medical University, China ; Department of Physical Therapy, China Rehabilitation Research Center, China
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Nardone R, Höller Y, Thomschewski A, Bathke AC, Ellis AR, Golaszewski SM, Brigo F, Trinka E. Assessment of corticospinal excitability after traumatic spinal cord injury using MEP recruitment curves: a preliminary TMS study. Spinal Cord 2015; 53:534-8. [PMID: 25665538 DOI: 10.1038/sc.2015.12] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 12/30/2014] [Accepted: 01/08/2015] [Indexed: 12/20/2022]
Abstract
STUDY DESIGN Transcranial magnetic stimulation study. OBJECTIVES To further investigate the corticospinal excitability changes after spinal cord injury (SCI), as assessed by means of transcranial magnetic stimulation (TMS). SETTING Merano (Italy) and Salzburg (Austria). METHODS We studied resting motor threshold (RMT), motor evoked potential (MEP) amplitude and recruitment curve in five subjects with good recovery after traumatic incomplete cervical SCI. RESULTS RMT did not differ significantly between patients and controls, whereas the slope of MEP recruitment curve was significantly increased in the patients. CONCLUSION This abnormal finding may represent an adaptive response after SCI. The impaired ability of the motor cortex to generate proper voluntary movement may be compensated by increasing spinal excitability. The easily performed measurement of MEP recruitment curve may provide a useful additional tool to improve the assessment and monitoring of motor cortical function in subjects with SCI. Increasing our knowledge of the corticospinal excitability changes in the functional recovery after SCI may also support the development of effective therapeutic strategies.
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Affiliation(s)
- R Nardone
- 1] Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria [2] Department of Neurology, Franz Tappeiner Hospital, Merano, Italy [3] Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Y Höller
- 1] Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria [2] Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - A Thomschewski
- 1] Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria [2] Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - A C Bathke
- 1] Department of Mathematics, Paris Lodron University, Salzburg, Austria [2] Department of Statistics, University of Kentucky, Lexington, KY, USA
| | - A R Ellis
- Department of Statistics, University of Kentucky, Lexington, KY, USA
| | - S M Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria
| | - F Brigo
- 1] Department of Neurology, Franz Tappeiner Hospital, Merano, Italy [2] Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - E Trinka
- 1] Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria [2] Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
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Gomes-Osman J, Field-Fote EC. Improvements in hand function in adults with chronic tetraplegia following a multiday 10-Hz repetitive transcranial magnetic stimulation intervention combined with repetitive task practice. J Neurol Phys Ther 2015; 39:23-30. [PMID: 25415549 PMCID: PMC4270905 DOI: 10.1097/npt.0000000000000062] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND PURPOSE Evidence suggests that the use of stimulation to increase corticomotor excitability improves hand function in persons with cervical spinal cord injury. We assessed effects of a multiday application of 10-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the corticomotor hand area combined with repetitive task practice (RTP) in participants with tetraplegia and neurologically healthy participants. METHODS Using a double-blind, randomized, crossover design, 11 participants with chronic tetraplegia and 10 neurologically healthy participants received 3 sessions of 10-Hz rTMS+RTP and 3 sessions of sham-rTMS+RTP to the corticomotor hand region controlling the weaker hand. Repetitive transcranial magnetic stimulation was interleaved with RTP of a skilled motor task between pulse trains. Hand function (Jebsen-Taylor Hand Function Test, pinch, and grasp strength) and corticomotor excitability (amplitude of motor-evoked potential) were assessed before and after the rTMS+RTP and sham-rTMS+RTP phases. We assessed significance, using paired t tests on pre-post differences, and effect sizes, using the standardized response mean. RESULTS RTMS+RTP was associated with larger effect sizes compared with sham-rTMS+RTP for improvement in Jebsen-Taylor Hand Function Test for both the trained hand (standardized response mean = 0.85 and 0.42, respectively) and non-trained hand (0.55 and 0.31, respectively), and for grasp strength of the trained hand in the group with cervical spinal cord injury (0.67 and 0.39, respectively) alone. Effect sizes for all other measures were small and there were no statistical between-condition differences in the outcomes assessed. DISCUSSION AND CONCLUSIONS Repetitive transcranial magnetic stimulation may be a valuable adjunct to RTP for improving hand function in persons with tetraplegia. Higher stimulation dose (frequency, intensity, and the number of sessions) may be associated with larger effects. VIDEO ABSTRACT AVAILABLE (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A82) for more insights from the authors.
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Affiliation(s)
- Joyce Gomes-Osman
- Department of Physical Therapy, University of Miami Miller School of Medicine, 5915 Ponce de Leon Blvd. 5th Floor Coral Gables, FL 33146, Miami, FL, 33136, USA
| | - Edelle C. Field-Fote
- Department of Physical Therapy, University of Miami Miller School of Medicine, 5915 Ponce de Leon Blvd. 5th Floor Coral Gables, FL 33146, Miami, FL, 33136, USA
- The Miami Project to Cure Paralysis, 1095 NW 14 Terrace, Miami FL, 33136, USA
- Crawford Research Institute, Shepherd Center, 2020 Peachtree Rd, Atlanta, GA, 30309, USA
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Gomes-Osman J, Field-Fote EC. Cortical vs. afferent stimulation as an adjunct to functional task practice training: a randomized, comparative pilot study in people with cervical spinal cord injury. Clin Rehabil 2014; 29:771-82. [PMID: 25381344 DOI: 10.1177/0269215514556087] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 09/26/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To assess single-session effects of three different types of stimuli known to increase cortical excitability when combined with functional task practice. DESIGN Randomized cross-over trial. PARTICIPANTS A total of 24 participants with chronic cervical spinal cord injury. INTERVENTIONS One 30-minute session of each, applied concurrently with functional task practice: transcranial direct current stimulation, vibration, and transcutaneous electrical nerve stimulation. MEASUREMENTS Nine-hole Peg Test, pinch force, visuomotor tracking, and cortical excitability were collected at pretest, posttest and late posttest (30 minutes after). Early effects (posttest minus pretest) and short-term persistence (late posttest minus pretest) were assessed using a general linear mixed model. Magnitude of effect size was assessed using the Cohen's d. RESULTS Transcutaneous electrical nerve stimulation was associated with moderate, significant early effects and short-term persistence on Nine-hole Peg Test performance (1.8 ±1.8, p = 0.003, d = 0.59; 2.0 ±2.5, p < 0.001, Cohen's d = 0.65, respectively). Transcranial direct current stimulation (1.8 ±2.5, p = 0.003, Cohen's d = 0.52) was also associated with significant short-term persistence of moderate size on Nine-hole Peg Test performance (1.8 ±2.5, p = 0.003, Cohen's d = 0.52) and visuomotor tracking performance (p = 0.05, d = 0.51). Early effects on corticomotor excitability were significant for transcutaneous electrical nerve stimulation (p = 0.003), approached significance for transcranial direct current stimulation (p = 0.07), and only vibration was associated with significant short-term persistence (p = 0.006). CONCLUSIONS Meaningful improvements in aspects of hand-related function that persisted at least 30 minutes after intervention were observed with transcutaneous electrical nerve stimulation and transcranial direct current stimulation, when combined with functional task practice.
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Affiliation(s)
- Joyce Gomes-Osman
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA Department of Physical Therapy, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Edelle C Field-Fote
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA Department of Physical Therapy, University of Miami Miller School of Medicine, Miami, FL, USA
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Nardone R, Höller Y, Brigo F, Orioli A, Tezzon F, Schwenker K, Christova M, Golaszewski S, Trinka E. Descending motor pathways and cortical physiology after spinal cord injury assessed by transcranial magnetic stimulation: a systematic review. Brain Res 2014; 1619:139-54. [PMID: 25251591 DOI: 10.1016/j.brainres.2014.09.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 08/06/2014] [Accepted: 09/15/2014] [Indexed: 02/02/2023]
Abstract
We performed here a systematic review of the studies using transcranial magnetic stimulation (TMS) as a research and clinical tool in patients with spinal cord injury (SCI). Motor evoked potentials (MEPs) elicited by TMS represent a highly accurate diagnostic test that can supplement clinical examination and neuroimaging findings in the assessment of SCI functional level. MEPs allows to monitor the changes in motor function and evaluate the effects of the different therapeutic approaches. Moreover, TMS represents a useful non-invasive approach for studying cortical physiology, and may be helpful in elucidating the pathophysiological mechanisms of brain reorganization after SCI. Measures of motor cortex reactivity, e.g., the short interval intracortical inhibition and the cortical silent period, seem to point to an increased cortical excitability. However, the results of TMS studies are sometimes contradictory or divergent, and should be replicated in a larger sample of subjects. Understanding the functional changes at brain level and defining their effects on clinical outcome is of crucial importance for development of evidence-based rehabilitation therapy. TMS techniques may help in identifying neurophysiological biomarkers that can reliably assess the extent of neural damage, elucidate the mechanisms of neural repair, predict clinical outcome, and identify therapeutic targets. Some researchers have begun to therapeutically use repetitive TMS (rTMS) in patients with SCI. Initial studies revealed that rTMS can induce acute and short duration beneficial effects especially on spasticity and neuropathic pain, but the evidence is to date still very preliminary and well-designed clinical trials are warranted. This article is part of a Special Issue entitled SI: Spinal cord injury.
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Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria.
| | - Yvonne Höller
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy; Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, Italy
| | - Andrea Orioli
- Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy
| | - Frediano Tezzon
- Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy
| | - Kerstin Schwenker
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Monica Christova
- Department of Physiology, Medical University of Graz, Graz, Austria
| | - Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
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Abstract
The motor cortex and the corticospinal system contribute to the control of a precision grip between the thumb and index finger. The involvement of subcortical pathways during human precision grip remains unclear. Using noninvasive cortical and cervicomedullary stimulation, we examined motor evoked potentials (MEPs) and the activity in intracortical and subcortical pathways targeting an intrinsic hand muscle when grasping a small (6 mm) cylinder between the thumb and index finger and during index finger abduction in uninjured humans and in patients with subcortical damage due to incomplete cervical spinal cord injury (SCI). We demonstrate that cortical and cervicomedullary MEP size was reduced during precision grip compared with index finger abduction in uninjured humans, but was unchanged in SCI patients. Regardless of whether cortical and cervicomedullary stimulation was used, suppression of the MEP was only evident 1-3 ms after its onset. Long-term (∼5 years) use of the GABAb receptor agonist baclofen by SCI patients reduced MEP size during precision grip to similar levels as uninjured humans. Index finger sensory function correlated with MEP size during precision grip in SCI patients. Intracortical inhibition decreased during precision grip and spinal motoneuron excitability remained unchanged in all groups. Our results demonstrate that the control of precision grip in humans involves premotoneuronal subcortical mechanisms, likely disynaptic or polysynaptic spinal pathways that are lacking after SCI and restored by long-term use of baclofen. We propose that spinal GABAb-ergic interneuronal circuits, which are sensitive to baclofen, are part of the subcortical premotoneuronal network shaping corticospinal output during human precision grip.
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Anwer S, Equebal A, Palekar TJ, Nezamuddin M, Neyaz O, Alghadir A. Effect of locomotor training on motor recovery and walking ability in patients with incomplete spinal cord injury: a case series. J Phys Ther Sci 2014; 26:951-3. [PMID: 25013303 PMCID: PMC4085228 DOI: 10.1589/jpts.26.951] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/08/2014] [Indexed: 11/24/2022] Open
Abstract
[Purpose] The aim of this study was to describe the effect of locomotor training on a
treadmill for three individuals who have an incomplete spinal cord injury (SCI). [Subjects
and Methods] Three indivduals (2 males, 1 female) with incomplete paraplegia participated
in this prospective case series. All subjects participated in locomotor training for a
maximum of 20 minutes on a motorized treadmill without elevation at a comfortable walking
speed three days a week for four weeks as an adjunct to a conventional physiotherapy
program. The lower extremity strength and walking capabilities were used as the outcome
measures of this study. Lower extremity strength was measured by lower extremity motor
score (LEMS). Walking capability was assessed using the Walking Index for Spinal Cord
Injury (WISCI II). [Results] An increase in lower extremity motor score and walking
capabilities at the end of training program was found. [Conclusion] Gait training on a
treadmill can enhance motor recovery and walking capabilities in subjects with incomplete
SCI. Further research is needed to generalize these findings and to identify which
patients might benefit from locomotor training.
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Affiliation(s)
- Shahnawaz Anwer
- Department of Rehabilitation Sciences, College of Applied Medical Sciences, King Saud University, KSA ; Padmashree Dr. D. Y. Patil College of Physiotherapy, Dr. D. Y. Patil Vidyapeeth India
| | - Ameed Equebal
- National Institute for the Orthopedically Handicapped (NIOH), India
| | - Tushar J Palekar
- Padmashree Dr. D. Y. Patil College of Physiotherapy, Dr. D. Y. Patil Vidyapeeth India
| | - M Nezamuddin
- National Institute for the Orthopedically Handicapped (NIOH), India
| | - Osama Neyaz
- National Institute for the Orthopedically Handicapped (NIOH), India
| | - Ahmad Alghadir
- Department of Rehabilitation Sciences, College of Applied Medical Sciences, King Saud University, KSA
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Thomas CK, Bakels R, Klein CS, Zijdewind I. Human spinal cord injury: motor unit properties and behaviour. Acta Physiol (Oxf) 2014; 210:5-19. [PMID: 23901835 DOI: 10.1111/apha.12153] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/31/2013] [Accepted: 07/29/2013] [Indexed: 01/03/2023]
Abstract
Spinal cord injury (SCI) results in widespread variation in muscle function. Review of motor unit data shows that changes in the amount and balance of excitatory and inhibitory inputs after SCI alter management of motoneurons. Not only are units recruited up to higher than usual relative forces when SCI leaves few units under voluntary control, the force contribution from recruitment increases due to elevation of twitch/tetanic force ratios. Force gradation and precision are also coarser with reduced unit numbers. Maximal unit firing rates are low in hand muscles, limiting voluntary strength, but are low, normal or high in limb muscles. Unit firing rates during spasms can exceed voluntary rates, emphasizing that deficits in descending drive limit force production. SCI also changes muscle properties. Motor unit weakness and fatigability seem universal across muscles and species, increasing the muscle weakness that arises from paralysis of units, motoneuron death and sensory impairment. Motor axon conduction velocity decreases after human SCI. Muscle contractile speed is also reduced, which lowers the stimulation frequencies needed to grade force when paralysed muscles are activated with patterned electrical stimulation. This slowing does not necessarily occur in hind limb muscles after cord transection in cats and rats. The nature, duration and level of SCI underlie some of these species differences, as do variations in muscle function, daily usage, tract control and fibre-type composition. Exploring this diversity is important to promote recovery of the hand, bowel, bladder and locomotor function most wanted by people with SCI.
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Affiliation(s)
- C. K. Thomas
- The Miami Project to Cure Paralysis, Departments of Neurological Surgery, and Physiology and Biophysics; University of Miami; Miami FL USA
| | - R. Bakels
- Department of Neuroscience; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
| | - C. S. Klein
- Rehabilitation Institute of Chicago; Chicago IL USA
| | - I. Zijdewind
- Department of Neuroscience; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
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Central correlates of impaired information processing in people with spinal cord injury. J Clin Neurophysiol 2013; 30:59-65. [PMID: 23377444 DOI: 10.1097/wnp.0b013e31827edb0c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This investigation examined the impact of spinal cord injury (SCI) on task-relevant processing using event-related potentials. Thirty-seven participants with chronic SCI and 37 healthy able-bodied controls were tested in this study. An auditory two-tone button press oddball discrimination paradigm was used to evoke the N100, P200, N200, and P300 components of the event-related potential. During the early sensory/perceptual stages of target stimulus processing, the SCI group showed an earlier right posterior P200 latency relative to the controls. In the later more cognitive stages, a pattern of diminished left and right posterior P300 amplitude was also evident. This was further coupled with increased false-positive errors and greater variability of response time in the SCI group. The results of this study indicate that people with SCI show disturbances in inhibitory function and alterations in both early perceptual encoding processes and in later executive functioning that engages contextual/memory-updating operations.
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28
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The Sir Ludwig Guttmann Lecture 2012: the contribution of Stoke Mandeville Hospital to spinal cord injuries. Spinal Cord 2012; 50:790-6. [DOI: 10.1038/sc.2012.109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
The corticospinal tract (CST) is a major descending pathway contributing to the control of voluntary movement in mammals. During the last decades anatomical and electrophysiological studies have demonstrated significant reorganization in the CST after spinal cord injury (SCI) in animals and humans. In animal models of SCI, anatomical evidence showed corticospinal sprouts rostral and caudal to the lesion and their integration into intraspinal axonal circuits. Electrophysiological data suggested that indirect connections from the primary motor cortex to forelimb motoneurons, via brainstem nuclei and spinal cord interneurons, or direct connections from slow uninjured corticospinal axons, might contribute to the control of movement after a CST injury. In humans with SCI, post mortem spinal cord tissue revealed anatomical changes in the CST some of which were similar but others markedly different from those found in animal models of SCI. Human electrophysiological studies have provided ample evidence for corticospinal reorganization after SCI that may contribute to functional recovery. Together these studies have revealed a large plastic capacity of the CST after SCI. There is also a limited understanding of the relationship between anatomical and electrophysiological changes in the CST and control of movement after SCI. Increasing our knowledge of the role of CST plasticity in functional restoration after SCI may support the development of more effective repair strategies.
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Affiliation(s)
- Martin Oudega
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, 4074 BST3, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA.
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30
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Bunday KL, Perez MA. Impaired crossed facilitation of the corticospinal pathway after cervical spinal cord injury. J Neurophysiol 2012; 107:2901-11. [PMID: 22357796 DOI: 10.1152/jn.00850.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In uninjured humans, it is well established that voluntary contraction of muscles on one side of the body can facilitate transmission in the contralateral corticospinal pathway. This crossed facilitatory effect may favor interlimb coordination and motor performance. Whether this aspect of corticospinal function is preserved after chronic spinal cord injury (SCI) is unknown. Here, using transcranial magnetic stimulation, we show in patients with chronic cervical SCI (C(5)-C(8)) that the size of motor evoked potentials (MEPs) in a resting intrinsic hand muscle remained unchanged during increasing levels of voluntary contraction with a contralateral distal or proximal arm muscle. In contrast, MEP size in a resting hand muscle was increased during the same motor tasks in healthy control subjects. The magnitude of voluntary electromyography was negatively correlated with MEP size after chronic cervical SCI and positively correlated in healthy control subjects. To examine the mechanisms contributing to MEP crossed facilitation we examined short-interval intracortical inhibition (SICI), interhemispheric inhibition (IHI), and motoneuronal behavior by testing F waves and cervicomedullary MEPs (CMEPs). During strong voluntary contractions SICI was unchanged after cervical SCI and decreased in healthy control subjects compared with rest. F-wave amplitude and persistence and CMEP size remained unchanged after cervical SCI and increased in healthy control subjects compared with rest. In addition, during strong voluntary contractions IHI was unchanged in cervical SCI compared with rest. Our results indicate that GABAergic intracortical circuits, interhemispheric glutamatergic projections between motor cortices, and excitability of index finger motoneurons are neural mechanisms underlying, at least in part, the lack of crossed corticospinal facilitation observed after SCI. Our data point to the spinal motoneurons as a critical site for modulating corticospinal transmission after chronic cervical SCI.
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Affiliation(s)
- Karen L Bunday
- Department of Physical Medicine and Rehabilitation, Center for the Neural Basis of Cognition, Systems Neuroscience Institute, University of Pittsburgh, Pittsburgh, PA, USA
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31
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Thiemann U, Bluschke A, Resch F, Teufert B, Klein C, Weisbrod M, Bender S. Cortical post-movement and sensory processing disentangled by temporary deafferentation. Neuroimage 2011; 59:1582-93. [PMID: 21907294 DOI: 10.1016/j.neuroimage.2011.08.075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 08/11/2011] [Accepted: 08/23/2011] [Indexed: 11/25/2022] Open
Abstract
Motor system calibration depends crucially on the adjustment to the consequences of a movement, which often occur when the movement itself is already completed. The mechanisms by which reafferent feedback information is compared to the programmed movement remain unclear. In the current study, the hypothesis of a short term memory trace in the motor cortex which outlasts quick movements and is generated independently from reafferent feedback was challenged by temporal deafferentation. Post-movement cortical potentials were recorded by high-resolution EEG during a reaction time task which required speeded unilateral right-hand or left-hand button presses. We analysed lateralized motor N700 (motor post-imperative negative variation), a post-movement component, under temporary deafferentation achieved through application of a blood pressure tourniquet in ten healthy adult subjects. Motor N700 persisted under deafferentation in the absence of reafferent tactile and proprioceptive feedback input into the sensorimotor cortex, which was abolished under deafferentation. Source analysis pointed towards continuing activation in the pre-/primary motor cortex. Thus, motor post-processing can be dissociated from reafferent sensory feedback. Motor cortex activation outlasts quick movements for about a second also in the absence of a reafferent signal. Continuing motor cortex activation could act as an internal motor model in motor learning and allow better adjustment of movements according to the evaluation of their consequences.
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Affiliation(s)
- Ulf Thiemann
- Department of Child and Adolescent Psychiatry, Center for Psychosocial Medicine, University of Heidelberg, Blumenstr. 8, 69115 Heidelberg, Germany.
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32
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Roy FD, Zewdie ET, Gorassini MA. Short-interval intracortical inhibition with incomplete spinal cord injury. Clin Neurophysiol 2011; 122:1387-95. [DOI: 10.1016/j.clinph.2010.11.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 11/10/2010] [Accepted: 11/22/2010] [Indexed: 12/14/2022]
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Functional and Corticomotor Changes in Individuals With Tetraplegia Following Unimanual or Bimanual Massed Practice Training With Somatosensory Stimulation. J Neurol Phys Ther 2010; 34:193-201. [DOI: 10.1097/npt.0b013e3181fbe692] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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35
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Hoffman LR, Field-Fote EC. Cortical reorganization following bimanual training and somatosensory stimulation in cervical spinal cord injury: a case report. Phys Ther 2007; 87:208-23. [PMID: 17213410 DOI: 10.2522/ptj.20050365] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND AND PURPOSE Deficits in upper-extremity function in individuals with tetraplegia are primarily due to the loss of motor pathways. Detrimental cortical reorganization, however, may create further loss of function. The purpose of this case report is to describe the cortical changes associated with a combination intervention using bimanual massed practice training with somatosensory stimulation. CASE DESCRIPTION "BR" was a 22-year-old man with C6 tetraplegia and hand impairment who participated in this training intervention for 3 weeks. OUTCOMES BR demonstrated improvements in sensory function, strength (the force-generating capacity of muscle), and performance of functional hand skills. Following the training, the cortical motor map of the biceps brachii muscle shifted anteriorly and increased in area and volume. DISCUSSION This is the first documented case in which changes in the size and location of the cortical map were associated with an intervention and improvement in function in an individual with tetraplegia. This case suggests that an intensive training intervention may induce both functional and neurophysiological changes.
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Affiliation(s)
- Larisa R Hoffman
- Department of Physical Therapy, University of Miami Miller School of Medicine, Coral Gables, FL 33146, USA
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36
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Steeves JD, Lammertse D, Curt A, Fawcett JW, Tuszynski MH, Ditunno JF, Ellaway PH, Fehlings MG, Guest JD, Kleitman N, Bartlett PF, Blight AR, Dietz V, Dobkin BH, Grossman R, Short D, Nakamura M, Coleman WP, Gaviria M, Privat A. Guidelines for the conduct of clinical trials for spinal cord injury (SCI) as developed by the ICCP panel: clinical trial outcome measures. Spinal Cord 2006; 45:206-21. [PMID: 17179972 DOI: 10.1038/sj.sc.3102008] [Citation(s) in RCA: 331] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
An international panel reviewed the methodology for clinical trials of spinal cord injury (SCI), and provided recommendations for the valid conduct of future trials. This is the second of four papers. It examines clinical trial end points that have been used previously, reviews alternative outcome tools and identifies unmet needs for demonstrating the efficacy of an experimental intervention after SCI. The panel focused on outcome measures that are relevant to clinical trials of experimental cell-based and pharmaceutical drug treatments. Outcome measures are of three main classes: (1) those that provide an anatomical or neurological assessment for the connectivity of the spinal cord, (2) those that categorize a subject's functional ability to engage in activities of daily living, and (3) those that measure an individual's quality of life (QoL). The American Spinal Injury Association impairment scale forms the standard basis for measuring neurologic outcomes. Various electrophysiological measures and imaging tools are in development, which may provide more precise information on functional changes following treatment and/or the therapeutic action of experimental agents. When compared to appropriate controls, an improved functional outcome, in response to an experimental treatment, is the necessary goal of a clinical trial program. Several new functional outcome tools are being developed for measuring an individual's ability to engage in activities of daily living. Such clinical end points will need to be incorporated into Phase 2 and Phase 3 trials. QoL measures often do not correlate tightly with the above outcome tools, but may need to form part of Phase 3 trial measures.
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Affiliation(s)
- J D Steeves
- ICORD, University of British Columbia (UBC) and Vancouver Coastal Health (VCH) Research Institute, Vancouver, BC, Canada
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37
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Shields CB, Ping Zhang Y, Shields LBE, Burke DA, Glassman SD. Objective assessment of cervical spinal cord injury levels by transcranial magnetic motor-evoked potentials. ACTA ACUST UNITED AC 2006; 66:475-83; discussion 483. [PMID: 17084191 DOI: 10.1016/j.surneu.2006.04.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Accepted: 04/25/2006] [Indexed: 11/24/2022]
Abstract
BACKGROUND The neurologic examination serves as the optimal method to record the level of spinal cord injury (SCI). However, this test is subject to interexaminer variability. To address this shortcoming, we describe a technique that uses transcranial magnetic motor-evoked potentials (tcMMEPs) and dermatomal somatosensory-evoked potentials (d-SSEPs) to more accurately measure the precise level of SCI. METHODS Two groups of subjects were studied: (1) complete cervical SCI (n = 10) and (2) neurologically intact volunteers (n = 10). Two additional patients were evaluated: one with a cervical central spinal cord syndrome and another with a head injury with a suspected cervical SCI. Each subject underwent upper extremity tcMMEPs and d-SSEPs. RESULTS Transcranial magnetic motor-evoked potentials were elicited from all upper limb myotomes (C4-T1, bilaterally) in neurologically intact volunteers (20 sides). The level of injury was determined using tcMMEPs by observing the lowest level of measurable response. The level of injury obtained using tcMMEPs was the same as that determined by neurologic examination in 13 (65%) of the 20 sides. In 7 sides, tcMMEP responses were obtained 1 level lower than that assessed by physical examination. Dermatomal somatosensory-evoked potentials were obtained from all dermatomes of volunteers tested in the laboratory compared with only 5 of the 9 patients with SCI who underwent d-SSEP testing. CONCLUSION Testing using tcMMEPs provides an objective supplement to the neurologic examination after acute cervical SCI. Dermatomal somatosensory-evoked potentials were of limited value in determining the level of cervical SCI.
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Affiliation(s)
- Christopher B Shields
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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38
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Cramer SC, Orr ELR, Cohen MJ, Lacourse MG. Effects of motor imagery training after chronic, complete spinal cord injury. Exp Brain Res 2006; 177:233-42. [PMID: 16944108 DOI: 10.1007/s00221-006-0662-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 08/01/2006] [Indexed: 11/25/2022]
Abstract
Abnormalities in brain motor system function are present following spinal cord injury (SCI) and could reduce effectiveness of restorative interventions. Motor imagery training, which can improve motor behavior and modulate brain function, might address this concern but has not been examined in subjects with SCI. Ten subjects with SCI and complete tetra-/paraplegia plus ten healthy controls underwent assessment before and after 7 days of motor imagery training to tongue and to foot. Motor imagery training significantly improved the behavioral outcome measure, speed of movement, in non-paralyzed muscles. Training was also associated with increased fMRI activation in left putamen, an area associated with motor learning, during attempted right foot movement in both groups, despite foot movements being present in controls and absent in subjects with SCI. This fMRI change was absent in a second healthy control group serially imaged without training. In subjects with SCI, training exaggerated, rather than normalized, baseline derangement of left globus pallidus activation. The current study found that motor imagery training improves motor performance and alters brain function in subjects with complete SCI despite lack of voluntary motor control and peripheral feedback. These effects of motor imagery training on brain function have not been previously described in a neurologically impaired population, and were similar to those found in healthy controls. Motor imagery might be of value as one component of a restorative intervention.
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Affiliation(s)
- Steven C Cramer
- Department of Neurology, Associate, Reeve-Irvine Research Center, University of California, Irvine, USA.
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Bender S, Becker D, Oelkers-Ax R, Weisbrod M. Cortical motor areas are activated early in a characteristic sequence during post-movement processing. Neuroimage 2006; 32:333-51. [PMID: 16698286 DOI: 10.1016/j.neuroimage.2006.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 02/22/2006] [Accepted: 03/07/2006] [Indexed: 11/18/2022] Open
Abstract
During motor learning in goal-directed reactions, a specific movement has to be associated with feedback about the movement's success. Such feedback often follows when the movement is already over. We investigated the time-course of post-movement cortical motor processing by high-resolution analysis of lateralized post-movement potentials in forewarned and simple reaction time tasks. In both paradigms we could separate a post-movement component (motor postimperative negative variation-mPINV) peaking about 500 ms after the button press (confirmed by electromyogram and accelerometer). mPINV could not be sufficiently explained by motor cortex activity related to EMG output and/or by sensory feedback. mPINV was enhanced by long intertrial intervals and its lateralization changed with response movement side. Its scalp potential distribution resembled (pre-)motor cortex activity during preceding movement stages and differed from the frontal motor potential peak (proprioceptive and somatosensory reafferent feedback); suggesting post-movement activation of pre-/primary motor cortex. Dipole source analysis yielded a single radial source near premotor cortex which explained lateralized mPINV almost completely. mPINV was present in simple reaction time tasks, indicating that mPINV is an independent component and does not represent delayed resolution of pre-movement negativity. An equivalent of "classical" PINV (cPINV) occurred later over prefrontal and anterior temporal sites in simple and forewarned reaction time tasks. Our results suggest that high-resolution analysis of lateralized movement-related potentials allows to image post-movement motor cortex activity and might provide insights into basic mechanisms of motor learning: A characteristic sequence might involve motor cortex activation (mPINV) before "higher order associative areas" come into play (cPINV).
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Affiliation(s)
- Stephan Bender
- Department for Child and Adolescent Psychiatry Psychiatric Hospital, University of Heidelberg, Blumenstrasse 8, 69115 Heidelberg, Germany.
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40
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Abstract
Injury to the cervical spinal cord adversely affects arm and hand function to varying degrees depending on the level and severity of injury. These impairments typically result in reduced independence in the performance of activities of daily living and limit participation in recreational activities. There is evidence to suggest individuals with incomplete spinal cord injury may benefit from intensive rehabilitation interventions aimed at improving hand and arm function. Massed practice (repetitive activity-based training) and somatosensory stimulation (prolonged peripheral nerve electrical stimulation at submotor threshold intensity) are 2 interventions that have been shown to improve strength and function in individuals with stroke, presumably by changing cortical excitability. These techniques, however, had not previously been investigated in individuals with spinal cord injury (SCI). In this article the stroke and SCI literature supporting the use of massed practice and somatosensory stimulation as a potential rehabilitative tool to promote recovery of function in individuals with incomplete cervical spinal cord injury (SCI) is reviewed. Recently published research using these novel techniques in which a combination of massed practice and somatosensory stimulation resulted in increased pinch grip strength and upper extremity function in individuals with incomplete cervical SCI when compared to subjects participating in massed practice alone is presented.
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Affiliation(s)
- Kristina S Beekhuizen
- College of Allied Health and Nursing, Department of Physical Therapy, Nova Southeastern University, Ft. Lauderdale, FL, USA.
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41
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Strutton PH, Theodorou S, Catley M, McGregor AH, Davey NJ. Corticospinal Excitability in Patients With Chronic Low Back Pain. ACTA ACUST UNITED AC 2005; 18:420-4. [PMID: 16189454 DOI: 10.1097/01.bsd.0000169063.84628.fe] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study was designed to investigate corticospinal excitability of lumbar muscles using transcranial magnetic stimulation (TMS) in patients with chronic low back pain and correlate this with self-rated measures of disability and pain. METHODS Twenty-four patients with chronic low back pain and 11 healthy control subjects were used in this study. TMS was delivered through an angled double-cone coil, with its cross-over on the vertex and a posterior-to-anterior current flow in the brain. Electromyographic (EMG) recordings were made from erector spinae (ES) muscles at the fourth lumbar level. Motor cortical excitability was assessed using motor threshold (MTh) for motor evoked potentials (MEPs) and threshold for silent period (SP) during facilitation of the back muscles. Latency, duration, and area of MEPs and SPs were also measured. RESULTS The latency, duration, and size of MEPs and SPs did not differ between the left and right ES muscles in either the patients or the control subjects and also did not differ between the patients and the control subjects. However, there was a significantly higher MTh and threshold for the SP in the patients as compared with the control subjects; the full significance of this requires further investigation. Interestingly, there was a positive correlation between the self-rated measure of disability (the Oswestry Disability Index score) and both the MTh and the threshold for the SP in the patients. There was also a positive correlation between the self-rated index of back pain and the threshold for the SP in the patients. This finding of an association between clinical and neurophysiologic measures reinforces the need for further research to establish the clinical relevance of these rises in MTh and SP threshold. CONCLUSIONS In summary, this study has revealed that corticospinal excitability, driving ES muscles close to the site of pain, is lowered in patients with chronic low back pain.
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Affiliation(s)
- Paul H Strutton
- Department of Musculoskeletal Surgery, Division of Surgery, Anaesthetics, and Intensive Care, Faculty of Medicine, Imperial College London, Charing Cross Campus, London, UK.
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King NKK, Kuppuswamy A, Strutton PH, Davey NJ. Estimation of cortical silent period following transcranial magnetic stimulation using a computerised cumulative sum method. J Neurosci Methods 2005; 150:96-104. [PMID: 16105686 DOI: 10.1016/j.jneumeth.2005.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Revised: 06/06/2005] [Accepted: 06/07/2005] [Indexed: 11/24/2022]
Abstract
The cortical silent period (CSP) following transcranial magnetic stimulation (TMS) of the motor cortex can be used to measure intra-cortical inhibition and changes in a number of important pathologies affecting the central nervous system. The main drawback of this technique has been the difficulty in accurately identifying the onset and offset of the cortical silent period leading to inter-observer variability. We developed an automated method based on the cumulative sum (Cusum) technique to improve the determination of the duration and area of the cortical silent period. This was compared with experienced raters and two other automated methods. We showed that the automated Cusum method reliably correlated with the experienced raters for both duration and area of CSP. Compared with the automated methods, the Cusum also showed the strongest correlation with the experienced raters. Our results show the Cusum method to be a simple, graphical and powerful method of detecting low-intensity CSP that can be easily automated using standard software.
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Affiliation(s)
- Nicolas K K King
- Department of Movement and Balance, Division of Neuroscience, Imperial College, Charing Cross Campus, London W6 8RP, UK.
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Belci M, Catley M, Husain M, Frankel HL, Davey NJ. Magnetic brain stimulation can improve clinical outcome in incomplete spinal cord injured patients. Spinal Cord 2004; 42:417-9. [PMID: 15111994 DOI: 10.1038/sj.sc.3101613] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Preliminary longitudinal clinical trial. OBJECTIVES To test the efficacy of repetitive transcranial magnetic stimulation (rTMS) in modulating corticospinal inhibition and improving recovery in stable incomplete spinal cord injury (iSCI). SETTING National Spinal Injuries Centre, Stoke Mandeville Hospital, Bucks, UK and Division of Neuroscience, Imperial College Faculty of Medicine, Charing Cross Hospital, London, UK. METHODS Four stable iSCI patients were treated with rTMS over the occipital cortex (sham treatment) and then over the motor cortex (real treatment). Patients were assessed using electrophysiological, clinical and functional measures before treatment, during sham treatment, during the therapeutic treatment and during a 3-week follow-up period. RESULTS Cortical inhibition was reduced during the treatment week. Perceptual threshold to electrical stimulation of the skin, ASIA clinical measures of motor and sensory function and time to complete a peg-board improved and remained improved into the follow-up period. CONCLUSION In this preliminary trial, rTMS has been shown to alter cortical inhibition in iSCI and improve the clinical and functional outcome. SPONSORSHIP This work was supported by the International Spinal Research Trust.
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Affiliation(s)
- M Belci
- Division of Neuroscience & Psychological Medicine, Faculty of Medicine, Imperial College, Charing Cross Hospital, London, UK
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44
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Patil PG, Carmena JM, Nicolelis MA, Turner DA. Ensemble Recordings Of Human Subcortical Neurons as a Source Of Motor Control Signals For a Brain-Machine Interface. Neurosurgery 2004. [DOI: 10.1227/01.neu.0000126872.23715.e5] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Iles JF, Ali AS, Savic G. Vestibular-evoked muscle responses in patients with spinal cord injury. Brain 2004; 127:1584-92. [PMID: 15128616 DOI: 10.1093/brain/awh173] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The vestibular system was activated by galvanic electrical stimulation in 22 patients with spinal cord injury. Three patients were studied standing and all were studied sitting. Electromyographic responses recorded in soleus (standing patients) and the erectores spinae (all patients) were compared with data from 18 control subjects. The vestibular stimulus polarity and head position were arranged so as to produce excitatory medium latency muscle responses in the controls. Responses in the patient group were present bilaterally, present unilaterally or absent below the level of injury. The amplitude of response recorded in erectores spinae at lumbar levels below the lesion in 21 patients (left and right side responses summed) and five control subjects was positively correlated with American Spinal Injuries Association (ASIA) grade: the smallest amplitudes were found in patients with the most severe impairment (Spearman rank correlation coefficient rs = 0.59; P = 0.002, two-tailed). The latency of response (averaged for both sides) was negatively correlated with ASIA grade in 21 patients: the longest latencies were found in patients with the most severe impairment (rs = -0.57; P < 0.01, two-tailed). Amplitude and latency were negatively correlated (rs = -0.72, P < 0.002, two-tailed). The latencies of responses recorded in the erectores spinae at different vertebral levels were linearly related to the vertical distance from the inion to the recording site in both patient and control groups. The conduction velocities of the spinal pathways activated by vestibular stimulation were 4.6 and 10.4 m/s in patient (recording below lesion) and control groups, respectively. Both clinical status (patients recording below lesion, patients recording above lesion and controls) and distance were significant predictors of latency (general linear model, P < 0.0005). It is concluded that measurement of vestibular-evoked responses could provide information on the level and density of spinal cord lesions.
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Affiliation(s)
- J F Iles
- Department of Zoology, University of Oxford, UK.
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46
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Ellaway PH, Anand P, Bergstrom EMK, Catley M, Davey NJ, Frankel HL, Jamous A, Mathias C, Nicotra A, Savic G, Short D, Theodorou S. Towards improved clinical and physiological assessments of recovery in spinal cord injury: a clinical initiative. Spinal Cord 2004; 42:325-37. [PMID: 14968107 DOI: 10.1038/sj.sc.3101596] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Clinical practice and scientific research may soon lead to treatments designed to repair spinal cord injury. Repair is likely to be partial in the first trials, extending only one or two segments below the original injury. Furthermore, treatments that are becoming available are likely to be applied to the thoracic spinal cord to minimise loss of function resulting from damage to surviving connections. These provisos have prompted research into the improvement of clinical and physiological tests designed (1) to determine the level and density of a spinal cord injury, (2) to provide reliable monitoring of recovery over one or two spinal cord segments, and (3) to provide indices of function provided by thoracic spinal root innervation, presently largely ignored in assessment of spinal cord injury. This article reviews progress of the Clinical Initiative, sponsored by the International Spinal Research Trust, to advance the clinical and physiological tests of sensory, motor and autonomic function needed to achieve these aims.
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Affiliation(s)
- P H Ellaway
- Division of Neuroscience and Psychological Medicine, Imperial College, London, UK
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Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive tool for the electrical stimulation of neural tissue, including cerebral cortex, spinal roots, and cranial and peripheral nerves. TMS can be applied as single pulses of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Single stimuli can depolarise neurons and evoke measurable effects. Trains of stimuli (repetitive TMS) can modify excitability of the cerebral cortex at the stimulated site and also at remote areas along functional anatomical connections. TMS might provide novel insights into the pathophysiology of the neural circuitry underlying neurological and psychiatric disorders, be developed into clinically useful diagnostic and prognostic tests, and have therapeutic uses in various diseases. This potential is supported by the available studies, but more work is needed to establish the role of TMS in clinical neurology.
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Affiliation(s)
- Masahito Kobayashi
- Laboratory for Magnetic Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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48
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Sailer A, Molnar GF, Cunic DI, Chen R. Effects of peripheral sensory input on cortical inhibition in humans. J Physiol 2002; 544:617-29. [PMID: 12381831 PMCID: PMC2290603 DOI: 10.1113/jphysiol.2002.028670] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cortical inhibitory systems play an important role in motor output. The motor cortex can be inhibited by intracortical mechanisms and by peripheral sensory inputs. We examined whether cortical inhibition from peripheral sensory input is mediated through previously identified intracortical inhibitory systems and how these inhibitory systems interact. Two types of intracortical inhibition were assessed by paired-pulse transcranial magnetic stimulation (TMS). Short-interval intracortical inhibition (SICI) was determined with a subthreshold conditioning stimulus (CS) followed by a test stimulus 2 ms later and long-interval intracortical inhibition (LICI) with suprathreshold conditioning and test stimuli 100 ms apart. Cortical inhibition from peripheral sensory input was induced by median nerve stimulation (MNS) of the right hand and followed by a suprathreshold TMS over the left motor cortex 200 ms later. The first set of experiments tested the effects of different test stimulus intensities on SICI, LICI and cortical inhibition induced by median nerve stimulation (MNSI). With higher test stimulus intensities, LICI and MNSI decreased whereas SICI showed a trend towards an increase. The extent of SICI, LICI and MNSI did not correlate. The second experiment assessed the interaction between MNSI and LICI. The results of applying MNSI and LICI simultaneously were compared with MNSI and LICI alone. MNSI was virtually abolished in the presence of LICI and LICI was also significantly decreased in the presence of MNSI. Thus, the effects of MNSI and LICI when applied together were much less than their expected additive effects when applied alone. The degree of interaction between MNSI and LICI was related to the combined strength of MNSI and LICI but not to the strength of LICI alone. The third experiment investigated the interaction between SICI and MNSI. MNSI and SICI were applied together and the results were compared with MNSI and SICI alone. SICI remained unchanged in the presence of MNSI. We conclude that MNSI is mediated by circuits distinct from those mediating LICI or SICI. The MNSI circuits seem to have an inhibitory interaction with the LICI circuits, whereas the SICI and MNSI circuits do not seem to interact.
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Affiliation(s)
- Alexandra Sailer
- Division of Neurology, Toronto Western Hospital University Health Network, University of Toronto, Ontario, Canada M5T 2S8
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Hornby TG, McDonagh JC, Reinking RM, Stuart DG. Motoneurons: A preferred firing range across vertebrate species? Muscle Nerve 2002; 25:632-648. [PMID: 11994957 DOI: 10.1002/mus.10105] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The term "preferred firing range" describes a pattern of human motor unit (MU) unitary discharge during a voluntary contraction in which the profile of the spike-frequency of the MU's compound action potential is dissociated from the profile of the presumed depolarizing pressure exerted on the unit's spinal motoneuron (MN). Such a dissociation has recently been attributed by inference to the presence of a plateau potential (PP) in the active MN. This inference is supported by the qualitative similarities between the firing pattern of human MUs during selected types of relatively brief muscle contraction and that of intracellularly stimulated, PP-generating cat MNs in a decerebrate preparation, and turtle MNs in an in vitro slice of spinal cord. There are also similarities between the stimulus-response behavior of intracellularly stimulated turtle MNs and human MUs during the elaboration of a slowly rising voluntary contraction. This review emphasizes that there are a variety of open issues concerning the PP. Nonetheless, a rapidly growing body of comparative vertebrate evidence supports the idea that the PP and other forms of non-linear MN behavior play a major role in the regulation of muscle force, from the lamprey to the human.
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Affiliation(s)
- T George Hornby
- Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona 85724-5051, USA
| | - Jennifer C McDonagh
- Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona 85724-5051, USA
| | - Robert M Reinking
- Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona 85724-5051, USA
| | - Douglas G Stuart
- Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona 85724-5051, USA
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Ochi A, Otsubo H, Honda Y, Hara Y, Sharma R, Elliott I, Rutka JT, Chuang SH, Kamijo KI, Kiyuna T, Yamazaki T, Snead OC. Electroencephalographic dipoles of spikes with and without myoclonic jerks caused by epilepsia partialis continua. J Child Neurol 2002; 17:127-31. [PMID: 11952073 DOI: 10.1177/088307380201700207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We used electroencephalographic (EEG) dipole analysis to investigate the generators of spikes with and without myoclonic jerks in a 12-year-old patient with epilepsia partialis continua secondary to left parietal cortical dysplasia. We recorded EEG and right wrist extensor electromyography (EMG) and collected 42 spikes with jerks (jerking spikes) and 42 spikes without jerks (nonjerking spikes). We applied a single moving dipole model to the individual and averaged spikes. Dipoles at the negative peak of individual jerking and nonjerking spikes were localized in the dysplastic area. At the onset of the averaged jerking spike that preceded the EMG discharges by 20 ms, the dipole was in the motor cortex, whereas for the averaged nonjerking spike, the dipole was in the sensory cortex. The dipole moment at averaged jerking spike onset was twice that of the averaged nonjerking spike. Electroencephalographic dipole analysis of averaged spikes differentiated the generator of jerking and nonjerking spikes in epilepsia partialis continua. Individual dipoles demonstrated the area of epileptogenic cortical dysplasia.
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MESH Headings
- Child
- Electroencephalography
- Electromyography
- Epilepsies, Myoclonic/diagnosis
- Epilepsies, Myoclonic/pathology
- Epilepsies, Myoclonic/physiopathology
- Epilepsies, Myoclonic/surgery
- Epilepsy, Partial, Motor/diagnosis
- Epilepsy, Partial, Motor/pathology
- Epilepsy, Partial, Motor/physiopathology
- Epilepsy, Partial, Motor/surgery
- Evoked Potentials/physiology
- Humans
- Magnetic Resonance Imaging
- Male
- Monitoring, Physiologic
- Motor Cortex/pathology
- Motor Cortex/physiopathology
- Parietal Lobe/abnormalities
- Parietal Lobe/pathology
- Parietal Lobe/physiopathology
- Postoperative Complications/diagnosis
- Postoperative Complications/physiopathology
- Treatment Outcome
- Video Recording
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Affiliation(s)
- Ayako Ochi
- Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada.
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