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Castro J, Pedrosa T, Alves I, Simão S, Swash M, de Carvalho M. A neurophysiological approach to mirror movements in amyotrophic lateral sclerosis. Clin Neurophysiol 2024; 158:27-34. [PMID: 38142663 DOI: 10.1016/j.clinph.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 11/21/2023] [Accepted: 12/01/2023] [Indexed: 12/26/2023]
Abstract
OBJECTIVE To investigate mirror activity in amyotrophic lateral sclerosis (ALS) patients, using a simple paradigm of signal quantification. METHODS Patients were asked to perform a brief isometric maximum contraction of the abductor digiti minimi (ADM) or tibialis anterior (TA) on one side, while relaxing the contralateral side of the body. Both sides were investigated. Signals were stored and analyzed offline, for quantification of electromyographic signal. Clinical signs of upper motor neuron (UMN) dysfunction, transcranial magnetic stimulation (TMS) for the upper (UL) and lower limbs (LL), the ADM ipsilateral cortical silent period (iSP) and the Edinburgh Cognitive and Behavioral ALS Screen (ECAS) cognitive scale were also investigated. RESULTS 42 ALS patients were included. In the 4 investigated muscles the amount of mirror activity was significantly higher than in the matched healthy group. The amount of mirror activity was similar between sides, but significantly higher in UL and LL with abnormal TMS results for ADM (p = 0.005) and TA (p = 0.002), as well as in UL with abnormal iSP values (p = 0.009). No association was found between mirror activity and clinical signs of UMN involvement. CONCLUSIONS Mirror activity is a common phenomenon in ALS. Mirror activity intensity corresponds to the severity of UMN dysfunction, as measured by TMS, and probably derives from the abnormal transcallosal inhibition as mirrored by iSP abnormality. SIGNIFICANCE Mirror activity is increased in ALS and is associated with abnormal transcallosal inhibition and UMN dysfunction.
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Affiliation(s)
- José Castro
- Instituto de Fisiologia, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Department of Neurosciences and Mental Health, Centro Hospitalar Universitário de Lisboa Norte, Lisbon, Portugal.
| | - Tomás Pedrosa
- Departamento de Bioengenharia, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Inês Alves
- Instituto de Fisiologia, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Sara Simão
- Instituto de Fisiologia, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Michael Swash
- Departments of Neurology and Neuroscience, Barts and the London School of Medicine, Queen Mary University of London, United Kingdom
| | - Mamede de Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Department of Neurosciences and Mental Health, Centro Hospitalar Universitário de Lisboa Norte, Lisbon, Portugal
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Hayes L, Taga M, Charalambous CC, Raju S, Lin J, Schambra HM. The distribution of transcallosal inhibition to upper extremity muscles is altered in chronic stroke. J Neurol Sci 2023; 450:120688. [PMID: 37224604 DOI: 10.1016/j.jns.2023.120688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 05/26/2023]
Abstract
OBJECTIVE To determine if the distribution of transcallosal inhibition (TI) acting on proximal and distal upper extremity muscles is altered in chronic stroke. METHODS We examined thirteen healthy controls and sixteen mildly to moderately impaired chronic stroke patients. We used transcranial magnetic stimulation (TMS) to probe TI from the contralesional onto ipsilesional hemisphere (assigned in controls). We recorded the ipsilateral silent period in the paretic biceps (BIC) and first dorsal interosseous (FDI). We measured TI strength, distribution gradient (TI difference between muscles), and motor impairment (Fugl-Meyer Assessment). RESULTS Both groups had stronger TI acting on their FDIs than BICs (p < 0.001). However, stroke patients also had stronger TI acting on their BICs than controls (p = 0.034), resulting in a flatter distribution of inhibition (p = 0.028). In patients, stronger FDI inhibition correlated with less hand impairment (p = 0.031); BIC inhibition was not correlated to impairment. CONCLUSION TI is more evenly distributed to the paretic FDI and BIC in chronic stroke. The relative increase in proximal inhibition does not relate to better function, as it does distally. SIGNIFICANCE The results expand our knowledge about segment-specific neurophysiology and its relevance to impairment after stroke.
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Affiliation(s)
- Leticia Hayes
- Department of Neurology, NYU Grossman School of Medicine, New York, United States.
| | - Myriam Taga
- Department of Neurology, NYU Grossman School of Medicine, New York, United States.
| | - Charalambos C Charalambous
- Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia, Cyprus; Center for Neuroscience and Integrative Brain Research (CENIBRE), University of Nicosia Medical School, Nicosia, Cyprus.
| | - Sharmila Raju
- Department of Neurology, NYU Grossman School of Medicine, New York, United States.
| | - Jing Lin
- Department of Rehabilitation Medicine, NYU Grossman School of Medicine, New York, United States.
| | - Heidi M Schambra
- Department of Neurology, NYU Grossman School of Medicine, New York, United States; Department of Rehabilitation Medicine, NYU Grossman School of Medicine, New York, United States.
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Xia X, Fomenko A, Nankoo JF, Zeng K, Wang Y, Zhang J, Lozano AM, Chen R. Time course of the effects of low-intensity transcranial ultrasound on the excitability of ipsilateral and contralateral human primary motor cortex. Neuroimage 2021; 243:118557. [PMID: 34487826 DOI: 10.1016/j.neuroimage.2021.118557] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 08/30/2021] [Accepted: 09/03/2021] [Indexed: 01/10/2023] Open
Abstract
Low-intensity transcranial ultrasound stimulation (TUS) is a promising non-invasive brain stimulation technique that can modulate the excitability of cortical and deep brain structures with a high degree of focality. Previous human studies showed that TUS decreases motor cortex (M1) excitability measured by transcranial magnetic stimulation (TMS), but whether the effects appear beyond sonication and whether TUS affects the excitability of other interconnected cortical areas is not known. The time course of M1 TUS on ipsilateral and contralateral M1 excitability was investigated in 22 healthy human subjects via TMS-induced motor-evoked potentials. With sonication duration of 500 ms, we found suppression of M1 excitability from 10 ms before to 20 ms after the end of sonication, and the effects were stronger with blocked design compared to interleaved design. There was no significant effect on contralateral M1 excitability. Using ex-vivo measurements, we showed that the ultrasound transducer did not affect the magnitude or time course of the TMS-induced electromagnetic field. We conclude that the online-suppressive effects of TUS on ipsilateral M1 cortical excitability slightly outlast the sonication but did not produce long-lasting effects. The absence of contralateral effects may suggest that there are little tonic interhemispheric interactions in the resting state, or the intensity of TUS was too low to induce transcallosal inhibition.
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Affiliation(s)
- Xue Xia
- School of Psychology, Shanghai University of Sport, Shanghai, China; Krembil Research Institute, University Health Network, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Anton Fomenko
- Krembil Research Institute, University Health Network, Toronto, ON, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada
| | | | - Ke Zeng
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Yanqiu Wang
- School of Psychology, Shanghai University of Sport, Shanghai, China; Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Jian Zhang
- School of Psychology, Shanghai University of Sport, Shanghai, China
| | - Andres M Lozano
- Krembil Research Institute, University Health Network, Toronto, ON, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada
| | - Robert Chen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada.
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Sivaramakrishnan A, Madhavan S. Reliability of transcallosal inhibition measurements for the lower limb motor cortex in stroke. Neurosci Lett 2021; 743:135558. [PMID: 33352282 PMCID: PMC7855415 DOI: 10.1016/j.neulet.2020.135558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 11/29/2022]
Abstract
Transcallosal inhibition (TCI) is a measure of between-hemisphere inhibitory control that can be evaluated with the ipsilateral silent period (iSP) transcranial magnetic stimulation (TMS) paradigm. The study of iSP for the lower extremity has been limited possibly due to the close orientation of the lower extremity motor representations. Change in TCI can provide insights into pathophysiological mechanisms underlying the asymmetry in corticomotor excitability in stroke. Here, we describe a method for iSP quantification and report reliability of iSP parameters for the tibialis anterior (TA) muscle in stroke. 26 individuals with stroke attended three sessions where single pulse TMS was used to measure TCI from the lesioned to non-lesioned hemisphere. A double cone coil was used for stimulating the ipsilateral motor cortex while the participant maintained an isometric contraction of the non-paretic TA. Absolute and relative reliability were computed for iSP latency, duration and area. iSP latency showed the lowest measurement error (absolute reliability) and iSP latency, duration and area showed good relative reliability (intraclass correlation coefficients > 0.6). This study suggests that iSP parameters for the tibialis anterior are reliable and attempts to provide a guideline for evaluating TCI for the lower extremity in stroke and other clinical populations.
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Affiliation(s)
- Anjali Sivaramakrishnan
- Brain Plasticity Lab, Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago (UIC), USA; Graduate Program in Rehabilitation Sciences, College of Applied Health Sciences, UIC, USA
| | - Sangeetha Madhavan
- Brain Plasticity Lab, Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago (UIC), USA.
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Khedr EM, Ahmed OG, Sayed HM, Abo-Elfetoh N, Ali AM, Gomaa AM. Electrophysiological differences in cortical excitability in different forms of dementia: A transcranial magnetic stimulation and laboratory biomarkers study. Neurophysiol Clin 2020; 50:185-193. [PMID: 32591186 DOI: 10.1016/j.neucli.2020.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/17/2020] [Accepted: 05/17/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The aim of the present study was to identify neurophysiologic markers to differentiate between Alzheimer dementia (AD), Vascular dementia (VaD), and Parkinson's disease dementia (PDD), and to examine their relationship to levels of transforming growth factor β1 (TGFβ1). METHODS The study included 15 patients with each type of dementia (AD, VaD, PDD) and 25 control subjects. Dementia patients were diagnosed according to the DiagnosticandStatisticalManualofMentalDisorders4thedition-revised(DSM-IV-R). Modified Mini Mental State Examination (MMMSE), motor cortex excitability including resting and active motor thresholds (rMT, aMT), input-output (I/O) curve, contralateral and ipsilateral silent periods (cSP, iSP), short-interval intracortical inhibition (SICI) at 1,2 and 4ms, and serum levels of TGFβ1 were examined. RESULTS There were no significant differences between groups with regards to age, sex, education or socioeconomic level. There was significant neuronal hyperexcitability in the form of reduced rMT and aMT and a shallower I/O curve in all three groups of dementia compared with the control group. The durations of cSP and iSP were longer in AD and PDD groups compared with the control group, whereas there were no significant differences in VaD. SICI was less effective in the three dementia groups than in the control group at intervals of 4ms. Serum levels of TGFβ1 were significantly elevated in all dementia groups in comparison with the control group. There was a significant negative correlation between serum level of TGFβ1 and cSP, iSP, and SICI across all patients and a significant negative correlation between serum level of TGFβ1 and iSP duration in AD. CONCLUSION Although motor thresholds were reduced in all patients, measures of SICI, cSP and iSP could distinguish between dementia groups. Serum level of TGFβ1 negatively correlated with iSP specifically in the AD group. This suggests that levels of TGFβ1 may relate to GABAergic dysfunction in dementia.
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Affiliation(s)
- Eman M Khedr
- Neurology and psychiatry department, Assiut university hospital, Assiut, Egypt.
| | - Omyma G Ahmed
- Medical physiology department, faculty of medicine, Assiut university, Assiut, Egypt
| | - Hanaa Mm Sayed
- Medical physiology department, faculty of medicine, Assiut university, Assiut, Egypt
| | - Noha Abo-Elfetoh
- Neurology and psychiatry department, Assiut university hospital, Assiut, Egypt
| | - Anwar M Ali
- Neurology and psychiatry department, Assiut university hospital, Assiut, Egypt
| | - Asmaa Ms Gomaa
- Medical physiology department, faculty of medicine, Assiut university, Assiut, Egypt
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Kuo IJ, Tang CW, Tsai YA, Tang SC, Lin CJ, Hsu SP, Liang WK, Juan CH, Zich C, Stagg CJ, Lee IH. Neurophysiological signatures of hand motor response to dual-transcranial direct current stimulation in subacute stroke: a TMS and MEG study. J Neuroeng Rehabil 2020; 17:72. [PMID: 32527268 PMCID: PMC7291576 DOI: 10.1186/s12984-020-00706-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/01/2020] [Indexed: 11/11/2022] Open
Abstract
Background Dual transcranial direct current stimulation (tDCS) to the bilateral primary motor cortices (M1s) has potential benefits in chronic stroke, but its effects in subacute stroke, when behavioural effects might be expected to be greater, have been relatively unexplored. Here, we examined the neurophysiological effects and the factors influencing responsiveness of dual-tDCS in subacute stroke survivors. Methods We conducted a randomized sham-controlled crossover study in 18 survivors with first-ever, unilateral subcortical ischaemic stroke 2–4 weeks after stroke onset and 14 matched healthy controls. Participants had real dual-tDCS (with an ipsilesional [right for controls] M1 anode and a contralesional M1 [left for controls] cathode; 2 mA for 20mins) and sham dual-tDCS on separate days, with concurrent paretic [left for controls] hand exercise. Using transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG), we recorded motor evoked potentials (MEPs), the ipsilateral silent period (iSP), short-interval intracortical inhibition, and finger movement-related cortical oscillations before and immediately after tDCS. Results Stroke survivors had decreased excitability in ipsilesional M1 with a relatively excessive transcallosal inhibition from the contralesional to ipsilesional hemisphere at baseline compared with controls, as quantified by decreased MEPs and increased iSP duration. Dual-tDCS led to increased MEPs and decreased iSP duration in ipsilesional M1. The magnitude of the tDCS-induced MEP increase in stroke survivors was predicted by baseline contralesional-to-ipsilesional transcallosal inhibition (iSP) ratio. Baseline post-movement synchronization in α-band activity in ipsilesional M1 was decreased after stroke compared with controls, and its tDCS-induced increase correlated with upper limb score in stroke survivors. No significant adverse effects were observed during or after dual-tDCS. Conclusions Task-concurrent dual-tDCS in subacute stroke can safely and effectively modulate bilateral M1 excitability and inter-hemispheric imbalance and also movement-related α-activity.
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Affiliation(s)
- I-Ju Kuo
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan.,Department of Neurosurgery, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Chih-Wei Tang
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan.,Department of Neurology, Far Eastern Memorial Hospital, No.21, Sec. 2, Nanya S. Rd., Banqiao Dist, New Taipei City, 220, Taiwan
| | - Yun-An Tsai
- Department of Neurosurgery, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Shuen-Chang Tang
- Department of Neurosurgery, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Chun-Jen Lin
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan.,Division of Cerebrovascular Diseases, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Shih-Pin Hsu
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, No.300, Zhongda Rd., Zhongli Dist, Taoyuan City, 320, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, No.300, Zhongda Rd., Zhongli Dist, Taoyuan City, 320, Taiwan
| | - Catharina Zich
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK.,Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, OX3 7JX, UK.,MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
| | - Charlotte J Stagg
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK.,Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, OX3 7JX, UK.,MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
| | - I-Hui Lee
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan. .,Division of Cerebrovascular Diseases, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan.
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Summers RLS, Chen M, MacKinnon CD, Kimberley TJ. Evidence for normal intracortical inhibitory recruitment properties in cervical dystonia. Clin Neurophysiol 2020; 131:1272-1279. [PMID: 32304844 DOI: 10.1016/j.clinph.2020.03.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/17/2020] [Accepted: 03/22/2020] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Dystonia is associated with reduced intracortical inhibition as measured by the cortical silent period (cSP); however, this may be due to abnormal cSP threshold or input-output properties. This study evaluated cSP recruitment properties in people with cervical dystonia (CD). METHODS Bilateral electromyographic recordings were collected in the upper trapezius muscle in response to transcranial magnetic stimulation of the left and right primary motor cortex in a group with CD (n = 19) and controls (n = 21). cSP threshold, cSP input-output properties at stimulation intensities from 1 to 1.4x the cSP threshold, ipsilateral silent period duration (iSP) and timing and magnitude of the contralateral and ipsilateral motor evoked potential (MEP) were assessed. RESULTS The cSP threshold, input-output properties, and contralateral MEP magnitude were not significantly different between groups (all p > 0.07). Hemispheric symmetry was present in the control group while the CD group had reduced iSP (p < 0.01) and a trend for reduced ipsilateral MEP response (p = 0.053) in the left hemisphere. CONCLUSIONS Recruitment properties of intracortical inhibition are similar between control and CD groups. Transcallosal inhibition is asymmetric between hemispheres in people with CD. SIGNIFICANCE Evidence of normal intracortical inhibition recruitment properties challenge the commonly held view that cortical inhibition is reduced in dystonia.
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Affiliation(s)
- Rebekah L S Summers
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, 426 Church St. SE, Minneapolis, MN 55455, USA; Department of Neurology, School of Medicine, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414, USA.
| | - Mo Chen
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, 426 Church St. SE, Minneapolis, MN 55455, USA; Non-invasive Neuromodulation Laboratory, MnDRIVE Initiative, University of Minnesota, 247, 717 Delaware St. SE, Minneapolis, MN 55414, USA
| | - Colum D MacKinnon
- Department of Neurology, School of Medicine, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414, USA
| | - Teresa J Kimberley
- Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, 426 Church St. SE, Minneapolis, MN 55455, USA; School of Health and Rehabilitation Sciences, Department of Physical Therapy, Massachusetts General Hospital, Institute of Health Professions, 36 First Ave, Boston, MA 02129, USA
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Khedr EM, Al Fawal B, Abdelwarith AM, Saber M, Tony AAH, El-Bassiony A, Rothwell JC. Changes in recruitment of motor cortex excitation and inhibition in patients with drug-induced tardive syndromes. Neurophysiol Clin 2019; 49:33-40. [PMID: 30366858 DOI: 10.1016/j.neucli.2018.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/22/2018] [Accepted: 10/03/2018] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES It has recently been suggested that drug-induced tardive syndromes (TS) might be due to maladaptive plasticity, which increases motor excitability in cerebral cortex and basal ganglia. In order to test this hypothesis, we performed the first measurements of cortical excitability in TS. METHODS Motor cortex excitability was examined using transcranial magnetic stimulation (TMS) in 22 TS patients and compared with that in 20 age and sex-matched healthy individuals. Resting and active motor threshold (RMT, AMT) and input-output curves (I/O curves) assessed corticospinal excitability. The duration of the contralateral silent period (cSP) at a range of stimulation intensities and ipsilateral silent period (iSP) were used as measures of inhibition. RESULTS There were no significant differences in RMT and AMT between patients and controls, although the input-output curves were significantly steeper in patients. The cSP (at different stimulus intensities) and iSP were both longer in the patients compared to the control group. However, most of this difference could be accounted for by increased recruitment of motor evoked potentials (MEPs) in patients. CONCLUSION TS is characterized by hyperexcitability of corticospinal output that might contribute to the lack of selectivity in muscle recruitment and contribute to excess involuntary movement. The findings are opposite to those in naturally-occurring hyperkinesia such as Sydenham's and Huntington's chorea, suggesting a fundamental difference in the pathophysiology.
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Flamand VH, Denis A, Allen-Demers F, Lavoie M, Tessier R, Schneider C. Altered transcallosal inhibition evidenced by transcranial magnetic stimulation highlights neurophysiological consequences of premature birth in early adulthood. J Neurol Sci 2018; 393:18-23. [PMID: 30098499 DOI: 10.1016/j.jns.2018.07.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 07/26/2018] [Accepted: 07/28/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND OBJECTIVE A very preterm birth can induce deleterious neurophysiological consequences beyond childhood; alterations of the corpus callosum (CC) are reported in adolescents born very preterm along with cognitive impairments. The question remains whether neurophysiological alterations are still detectable in adulthood such as an alteration in CC inhibitory function. The aim of the present study was thus to examine transcallosal inhibition in young adults born very preterm compared to counterparts born at term. STUDY PARTICIPANTS & METHODS Transcallosal inhibition was probed by measuring the ipsilateral silent period (iSP) using transcranial magnetic stimulation (TMS) in 13 young adults born at 33w of gestation or less (20 ± 3. 2y) and 12 young adults born at term (22 ± 1. 75y). Single high-intensity TMS were delivered to the primary motor cortex (M1) ipsilateral to the preactivated first dorsal interosseous (FDI) muscle. Occurrence, latency, and duration of iSP were measured in the FDI EMG activity, for both hemispheres alternatively (10-12 trials each) along with their resting motor threshold (RMT). RESULTS In individuals born very preterm as compared to individuals born at term, ISP occurred less frequently (p < .0001), its latency was longer (p = .004), especially in the non-dominant hemisphere, its duration shorter (p < .0001), and RMT was higher in the non-dominant M1 than in the dominant. CONCLUSIONS Impairment of transcallosal inhibition along with asymmetry of M1 excitability in young adults born very preterm as compared to those born at term underline that neurophysiological consequences of a preterm birth can still be detected in early adulthood.
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Peterson DS, Fling BW. How changes in brain activity and connectivity are associated with motor performance in people with MS. Neuroimage Clin 2017; 17:153-162. [PMID: 29071209 PMCID: PMC5651557 DOI: 10.1016/j.nicl.2017.09.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/22/2017] [Accepted: 09/25/2017] [Indexed: 01/18/2023]
Abstract
People with multiple sclerosis (MS) exhibit pronounced changes in brain structure, activity, and connectivity. While considerable work has begun to elucidate how these neural changes contribute to behavior, the heterogeneity of symptoms and diagnoses makes interpretation of findings and application to clinical practice challenging. In particular, whether MS related changes in brain activity or brain connectivity protect against or contribute to worsening motor symptoms is unclear. With the recent emergence of neuromodulatory techniques that can alter neural activity in specific brain regions, it is critical to establish whether localized brain activation patterns are contributing to (i.e. maladaptive) or protecting against (i.e. adaptive) progression of motor symptoms. In this manuscript, we consolidate recent findings regarding changes in supraspinal structure and activity in people with MS and how these changes may contribute to motor performance. Furthermore, we discuss a hypothesis suggesting that increased neural activity during movement may be either adaptive or maladaptive depending on where in the brain this increase is observed. Specifically, we outline preliminary evidence suggesting sensorimotor cortex activity in the ipsilateral cortices may be maladaptive in people with MS. We also discuss future work that could supply data to support or refute this hypothesis, thus improving our understanding of this important topic.
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Affiliation(s)
- Daniel S Peterson
- Arizona State University, Tempe, AZ, USA; Veterans Affairs Phoenix Medical Center Phoenix, AZ, USA.
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Fleming MK, Rothwell JC, Sztriha L, Teo JT, Newham DJ. The effect of transcranial direct current stimulation on motor sequence learning and upper limb function after stroke. Clin Neurophysiol 2017; 128:1389-98. [PMID: 28410884 DOI: 10.1016/j.clinph.2017.03.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 03/19/2017] [Accepted: 03/24/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To assess the impact of electrode arrangement on the efficacy of tDCS in stroke survivors and determine whether changes in transcallosal inhibition (TCI) underlie improvements. METHODS 24 stroke survivors (3-124months post-stroke) with upper limb impairment participated. They received blinded tDCS during a motor sequence learning task, requiring the paretic arm to direct a cursor to illuminating targets on a monitor. Four tDCS conditions were studied (crossover); anodal to ipsilesional M1, cathodal to contralesional M1, bihemispheric, sham. The Jebsen Taylor hand function test (JTT) was assessed pre- and post-stimulation and TCI assessed as the ipsilateral silent period (iSP) duration using transcranial magnetic stimulation. RESULTS The time to react to target illumination reduced with learning of the movement sequence, irrespective of tDCS condition (p>0.1). JTT performance improved after unilateral tDCS (anodal or cathodal) compared with sham (p<0.05), but not after bihemispheric (p>0.1). There was no effect of tDCS on change in iSP duration (p>0.1). CONCLUSIONS Unilateral tDCS is effective for improving JTT performance, but not motor sequence learning. SIGNIFICANCE This has implications for the design of future clinical trials.
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Khedr EM, Gabra RH, Noaman M, Abo Elfetoh N, Farghaly HSM. Cortical excitability in tramadol dependent patients: A transcranial magnetic stimulation study. Drug Alcohol Depend 2016; 169:110-116. [PMID: 27810653 DOI: 10.1016/j.drugalcdep.2016.09.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 09/04/2016] [Accepted: 09/20/2016] [Indexed: 12/01/2022]
Abstract
BACKGROUND Addiction to tramadol, a widely used analgesic, is becoming increasingly common. Tramadol can also induce seizures even after a single clinical dose. We tested whether the epileptogenicity of tramadol was associated with any changes in cortical excitability and inhibitory transmission using transcranial magnetic stimulation (TMS). METHODS The study included 16 tramadol dependent patients and 15 age and sex matched healthy volunteers. Clinical evaluation was conducted using an addiction severity index. TMS assessment of excitability was conducted on the motor cortex since the response to each TMS pulse at that site is easily measured in terms of the amplitude of the twitches it evokes in contralateral muscles. Measures included resting and active motor threshold (RMT and AMT respectively), motor evoked potential (MEP) amplitude, cortical silent period (CSP) duration, transcallosal inhibition (TCI), and short interval intracortical inhibition and facilitation (SICI and ICF respectively). Urinary level of tramadol was measured immediately before assessing cortical excitability in each patient. RESULTS RMT and AMT were significantly lower, the duration of the CSP was shorter and SICI was reduced in patients compared with the control group. These findings are suggestive of increased neural excitability and reduced GABAergic inhibition following exposure to tramadol. Also there were negative correlations between the severity of tramadol dependence and a number of cortical excitability parameters (AMT, RMT, and CSP with P=0.002, 0.005, and 0.04 respectively). CONCLUSIONS The results provide evidence for hyperexcitability of the motor cortex coupled with inhibitory deficits in tramadol dependent patients.
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Affiliation(s)
- Eman M Khedr
- Neuropsychiatry Department, Assiut University Hospital, Assiut, Egypt.
| | - Romany H Gabra
- Neuropsychiatry Department, Assiut University Hospital, Assiut, Egypt
| | - Mostafa Noaman
- Neuropsychiatry Department, Assiut University Hospital, Assiut, Egypt
| | - Noha Abo Elfetoh
- Neuropsychiatry Department, Assiut University Hospital, Assiut, Egypt
| | - Hanan S M Farghaly
- Pharmacology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
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Khedr EM, Elbeh KAM, Elserogy Y, Khalifa HE, Ahmed MA, Hafez MH, Ali AM, Elfetoh NA. Motor cortical excitability in obsessive-compulsive disorder: Transcranial magnetic stimulation study. Neurophysiol Clin 2016; 46:135-43. [PMID: 27016878 DOI: 10.1016/j.neucli.2016.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 01/28/2016] [Accepted: 02/15/2016] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES Transcranial magnetic stimulation is a non-invasive method of stimulating the brain that is increasingly being used in neuropsychiatric research. Previous work has suggested that the pathophysiology of obsessive-compulsive disorder (OCD) may involve dysfunction of excitatory and/or inhibitory brain function. This study aimed to extend those findings. METHODS The study included 45 OCD patients and 15 age- and sex-matched healthy volunteers. Clinical evaluation was conducted using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Hamilton Anxiety Rating Scale (HAM-A), and Clinical Global Impression rating scale (CGI). Physiological measures were resting and active motor thresholds (RMT and AMT), motor evoked potential (MEP) amplitude, cortical silent period (CSP) and transcallosal inhibition (TCI) durations, short-interval intracortical inhibition (SICI), and intracortical facilitation. RESULTS RMT and AMT were significantly lower in patients than in the control group. The mean duration of the CSP and TCI were also significantly shorter. Obsessive trait was associated with significant reduction of TCI duration compared to compulsive trait. There was significant reduction in SICI in OCD patients compared to controls. There were no significant correlations between the Y-BOCS, HAM-A and CGI scores and the cortical excitability parameters. CONCLUSION These results provide further evidence for inhibitory deficits or increased facilitation in cortical circuits of patients with OCD.
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Affiliation(s)
- Eman M Khedr
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt.
| | - Khaled A M Elbeh
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
| | - Yasser Elserogy
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
| | - Hossam E Khalifa
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
| | - Mohamed A Ahmed
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
| | - Mahmoud H Hafez
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
| | - Anwar M Ali
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
| | - Noha A Elfetoh
- Department of neuropsychiatry, faculty of medicine, Assiut university hospital, 71511 Assiut, Egypt
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Takechi U, Matsunaga K, Nakanishi R, Yamanaga H, Murayama N, Mafune K, Tsuji S. Longitudinal changes of motor cortical excitability and transcallosal inhibition after subcortical stroke. Clin Neurophysiol 2014; 125:2055-69. [PMID: 24636830 DOI: 10.1016/j.clinph.2014.01.034] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 12/25/2013] [Accepted: 01/02/2014] [Indexed: 11/24/2022]
Abstract
OBJECTIVE A general lack of longitudinal studies on interhemispheric interactions following stroke led us to use transcranial magnetic stimulation (TMS) to examine changes in corticospinal/intracortical excitability and transcallosal inhibition over a 1-year period following subcortical stroke. METHODS We measured TMS parameters such as motor threshold (MT), short-interval intracortical inhibition (SICI), and ipsilateral silent period (iSP) and evaluated clinical scores at three time-points (T1, T2, and T3) in 24 patients and 25 age-matched healthy subjects. RESULTS At T1, we observed reduced MTs and SICIs with prolonged iSPs in the unaffected hemisphere (UH). In contrast, increased MTs and reduced SICIs were observed in the affected hemisphere (AH). These abnormalities gradually reduced and no MEP response to TMS at T1 predicted a worse prognosis. The prolonged iSP at T1 was associated with more severe impairments, but it did not necessarily predict a worse prognosis after 1year. CONCLUSIONS UH excitability was increased at the post-acute time-period, which may have resulted in enhanced transcallosal inhibition to the AH. However, it is unclear whether there was a causal relationship between the enhanced transcallosal inhibition and the extent of clinical recovery. SIGNIFICANCE This is the first study to demonstrate changes in transcallosal inhibition over a longitudinal period following stroke.
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Affiliation(s)
- Utako Takechi
- Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Japan.
| | - Kaoru Matsunaga
- Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan
| | - Ryoji Nakanishi
- Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan
| | - Hiroaki Yamanaga
- Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan
| | - Nobuki Murayama
- Department of Human and Environmental Informatics, Graduate School of Science and Technology, Kumamoto University, Japan
| | - Kosuke Mafune
- Department of Mental Health, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan
| | - Sadatoshi Tsuji
- Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Japan
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