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Beaulieu LD, Flamand VH, Massé-Alarie H, Schneider C. Reliability and minimal detectable change of transcranial magnetic stimulation outcomes in healthy adults: A systematic review. Brain Stimul 2016; 10:196-213. [PMID: 28031148 DOI: 10.1016/j.brs.2016.12.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) is used worldwide for noninvasively testing human motor systems but its psychometric properties remain unclear. OBJECTIVE/HYPOTHESIS This work systematically reviewed studies on the reliability of TMS outcome measures of primary motor cortex (M1) excitability in healthy humans, with an emphasis on retrieving minimal detectable changes (MDC). METHODS The literature search was performed in three databases (Pubmed, CINAHL, Embase) up to June 2016 and additional studies were identified through hand-searching. French and English-written studies had to report the reliability of at least one TMS outcome of M1 in healthy humans. Two independent raters assessed the eligibility of potential studies, and eligible articles were reviewed using a structured data extraction form and two critical appraisal scales. RESULTS A total of 34 articles met the selection criteria, which tested the intra- and inter-rater reliability (relative and absolute subtypes) of several TMS outcomes. However, our critical appraisal of studies raised concerns on the applicability and generalization of results because of methodological and statistical pitfalls. Importantly, MDC were generally large and likely affected by various factors, especially time elapsed between sessions and number of stimuli delivered. CONCLUSIONS This systematic review underlined that the evidence about the reliability of TMS outcomes is scarce and affected by several methodological and statistical problems. Data and knowledge of the review provided however relevant insights on the ability of TMS outcomes to track plastic changes within an individual or within a group, and recommendations were made to level up the quality of future work in the field.
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Affiliation(s)
- Louis-David Beaulieu
- Clinical Neuroscience and Neurostimulation Laboratory, CHU de Québec Research Center - Neuroscience Division, Quebec City, Qc, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Qc, Canada.
| | - Véronique H Flamand
- Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Qc, Canada; Center for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Qc, Canada
| | - Hugo Massé-Alarie
- Clinical Neuroscience and Neurostimulation Laboratory, CHU de Québec Research Center - Neuroscience Division, Quebec City, Qc, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Qc, Canada
| | - Cyril Schneider
- Clinical Neuroscience and Neurostimulation Laboratory, CHU de Québec Research Center - Neuroscience Division, Quebec City, Qc, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Qc, Canada
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102
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Chervyakov AV, Sinitsyn DO, Piradov MA. Variability of Neuronal Responses: Types and Functional Significance in Neuroplasticity and Neural Darwinism. Front Hum Neurosci 2016; 10:603. [PMID: 27932969 PMCID: PMC5122744 DOI: 10.3389/fnhum.2016.00603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/11/2016] [Indexed: 12/21/2022] Open
Abstract
HIGHLIGHTS We suggest classifying variability of neuronal responses as follows: false (associated with a lack of knowledge about the influential factors), "genuine harmful" (noise), "genuine neutral" (synonyms, repeats), and "genuine useful" (the basis of neuroplasticity and learning).The genuine neutral variability is considered in terms of the phenomenon of degeneracy.Of particular importance is the genuine useful variability that is considered as a potential basis for neuroplasticity and learning. This type of variability is considered in terms of the neural Darwinism theory. In many cases, neural signals detected under the same external experimental conditions significantly change from trial to trial. The variability phenomenon, which complicates extraction of reproducible results and is ignored in many studies by averaging, has attracted attention of researchers in recent years. In this paper, we classify possible types of variability based on its functional significance and describe features of each type. We describe the key adaptive significance of variability at the neural network level and the degeneracy phenomenon that may be important for learning processes in connection with the principle of neuronal group selection.
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Affiliation(s)
| | - Dmitry O Sinitsyn
- Research Center of NeurologyMoscow, Russia; Semenov Institute of Chemical Physics, Russian Academy of SciencesMoscow, Russia
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103
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Clinical Factors Underlying the Inter-individual Variability of the Resting Motor Threshold in Navigated Transcranial Magnetic Stimulation Motor Mapping. Brain Topogr 2016; 30:98-121. [PMID: 27815647 DOI: 10.1007/s10548-016-0536-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
Correctly determining individual's resting motor threshold (rMT) is crucial for accurate and reliable mapping by navigated transcranial magnetic stimulation (nTMS), which is especially true for preoperative motor mapping in brain tumor patients. However, systematic data analysis on clinical factors underlying inter-individual rMT variability in neurosurgical motor mapping is sparse. The present study examined 14 preselected clinical factors that may underlie inter-individual rMT variability by performing multiple regression analysis (backward, followed by forward model comparisons) on the nTMS motor mapping data of 100 brain tumor patients. Data were collected from preoperative motor mapping of abductor pollicis brevis (APB), abductor digiti minimi (ADM), and flexor carpi radialis (FCR) muscle representations among these patients. While edema and age at exam in the ADM model only jointly reduced the unexplained variance significantly, the other factors kept in the ADM model (gender, antiepileptic drug intake, and motor deficit) and each of the factors kept in the APB and FCR models independently significantly reduced the unexplained variance. Hence, several clinical parameters contribute to inter-individual rMT variability and should be taken into account during initial and follow-up motor mappings. Thus, the present study adds basic evidence on inter-individual rMT variability, whereby some of the parameters are specific to brain tumor patients.
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104
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Corticospinal and transcallosal modulation of unilateral and bilateral contractions of lower limbs. Eur J Appl Physiol 2016; 116:2197-2214. [DOI: 10.1007/s00421-016-3475-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/11/2016] [Indexed: 10/21/2022]
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105
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N100 as a generic cortical electrophysiological marker based on decomposition of TMS-evoked potentials across five anatomic locations. Exp Brain Res 2016; 235:69-81. [PMID: 27628235 DOI: 10.1007/s00221-016-4773-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/06/2016] [Indexed: 12/25/2022]
Abstract
N100, the negative peak of electrical response occurring around 100 ms, is present in diverse functional paradigms including auditory, visual, somatic, behavioral and cognitive tasks. We hypothesized that the presence of the N100 across different paradigms may be indicative of a more general property of the cerebral cortex regardless of functional or anatomic specificity. To test this hypothesis, we combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to measure cortical excitability by TMS across cortical regions without relying on specific sensory, cognitive or behavioral modalities. The five stimulated regions included left prefrontal, left motor, left primary auditory cortices, the vertex and posterior cerebellum with stimulations performed using supra- and subthreshold intensities. EEG responses produced by TMS stimulation at the five locations all generated N100s that peaked at the vertex. The amplitudes of the N100s elicited by these five diverse cortical origins were statistically not significantly different (all uncorrected p > 0.05). No other EEG response components were found to have this global property of N100. Our findings suggest that anatomy- and modality-specific interpretation of N100 should be carefully evaluated, and N100 by TMS may be used as a biomarker for evaluating local versus general cortical properties across the brain.
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106
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Radel R, Pjevac D, Davranche K, d'Arripe-Longueville F, Colson SS, Lapole T, Gruet M. Does intrinsic motivation enhance motor cortex excitability? Psychophysiology 2016; 53:1732-1738. [DOI: 10.1111/psyp.12732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 07/04/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Rémi Radel
- Laboratoire LAMHESS (EA 6312), Université de Nice Sophia Antipolis and Université de Toulon; France
| | - Dusan Pjevac
- Laboratoire LAMHESS (EA 6312), Université de Nice Sophia Antipolis and Université de Toulon; France
| | - Karen Davranche
- Aix-Marseille Université, CNRS; LPC UMR 7290, FR3C FR 3512 1331 Marseille France
| | | | - Serge S. Colson
- Laboratoire LAMHESS (EA 6312), Université de Nice Sophia Antipolis and Université de Toulon; France
| | - Thomas Lapole
- Univ Lyon, UJM-Saint-Etienne, LIBM; F-42023 Saint-Etienne France
| | - Mathieu Gruet
- Laboratoire LAMHESS (EA 6312), Université de Nice Sophia Antipolis and Université de Toulon; France
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107
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Reliability and Variability of tDCS Induced Changes in the Lower Limb Motor Cortex. Brain Sci 2016; 6:brainsci6030026. [PMID: 27472368 PMCID: PMC5039455 DOI: 10.3390/brainsci6030026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/15/2016] [Accepted: 07/25/2016] [Indexed: 11/21/2022] Open
Abstract
Background: Transcranial direct current stimulation (tDCS) is emerging as a promising adjuvant to enhance motor function. However, there has been increasing reservations about the reliability and variability of the neuromodulatory effects evoked by tDCS. Objective/Hypothesis: The main purpose of this study was to explore the test-retest reliability and inter-individual variability of tDCS of the lower limb M1 and the relationship between transcranial magnetic stimulation (TMS)-related measures and tDCS-induced changes. Methods: Fifteen healthy participants received anodal tDCS of the lower limb M1 either when performing a lower limb motor task or when the limb was at rest. Each condition was tested twice. tDCS induced changes in corticomotor excitability of the tibialis anterior muscle were measured using TMS. A repeated measures ANOVA was performed to examine efficacy of tDCS between the two task conditions. Intraclass correlation coefficients (ICC) and variance component analyses were performed to examine reliability and variability respectively. Results: A significant increase in in corticomotor excitability was noted for the tDCS-task condition at 140% active motor threshold (AMT) and when comparing recruitment curve slopes, but not at 120% and 130% AMT. Overall, ICC values between testing days for each stimulation condition ranged from 0.6–0.9. Higher ICCs were seen for higher TMS intensities (140% AMT) and recruitment curve slopes. Inter-individual variability contributed to 34% of the exhibited variance. Conclusions: Our data suggest that the TMS-related measure used to assess neuromodulation after tDCS has an effect on its perceived test-retest reliability and inter-individual variability. Importantly, we noticed that a high reliability and low variability does not necessarily indicate clinical efficacy of tDCS as some participants showed little to no modulation of corticomotor excitability consistently.
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108
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Cassidy JM, Chu H, Chen M, Kimberley TJ, Carey JR. Interhemispheric Inhibition Measurement Reliability in Stroke: A Pilot Study. Neuromodulation 2016; 19:838-847. [PMID: 27333364 DOI: 10.1111/ner.12459] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/02/2016] [Accepted: 04/29/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Reliable transcranial magnetic stimulation (TMS) measures for probing corticomotor excitability are important when assessing the physiological effects of noninvasive brain stimulation. The primary objective of this study was to examine test-retest reliability of an interhemispheric inhibition (IHI) index measurement in stroke. MATERIALS AND METHODS Ten subjects with chronic stroke (≥6 months) completed two IHI testing sessions per week for three weeks (six testing sessions total). A single investigator measured IHI in the contra-to-ipsilesional primary motor cortex direction and in the opposite direction using bilateral paired-pulse TMS. Weekly sessions were separated by 24 hours with a 1-week washout period separating testing weeks. To determine if motor-evoked potential (MEP) quantification method affected measurement reliability, IHI indices computed from both MEP amplitude and area responses were found. Reliability was assessed with two-way, mixed intraclass correlation coefficients (ICC(3,k) ). Standard error of measurement and minimal detectable difference statistics were also determined. RESULTS With the exception of the initial testing week, IHI indices measured in the contra-to-ipsilesional hemisphere direction demonstrated moderate to excellent reliability (ICC = 0.725-0.913). Ipsi-to-contralesional IHI indices depicted poor or invalid reliability estimates throughout the three-week testing duration (ICC= -1.153-0.105). The overlap of ICC 95% confidence intervals suggested that IHI indices using MEP amplitude vs. area measures did not differ with respect to reliability. CONCLUSIONS IHI indices demonstrated varying magnitudes of reliability irrespective of MEP quantification method. Several strategies for improving IHI index measurement reliability are discussed.
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Affiliation(s)
- Jessica M Cassidy
- Department of Physical Medicine and Rehabilitation, Programs in Physical Therapy and Rehabilitation Science, University of Minnesota, Minneapolis, MN, USA
| | - Haitao Chu
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Mo Chen
- Institute for Engineering in Medicine, University of Minnesota, Minneapolis, MN
| | - Teresa J Kimberley
- Department of Physical Medicine and Rehabilitation, Programs in Physical Therapy and Rehabilitation Science, University of Minnesota, Minneapolis, MN, USA
| | - James R Carey
- Department of Physical Medicine and Rehabilitation, Programs in Physical Therapy and Rehabilitation Science, University of Minnesota, Minneapolis, MN, USA
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109
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Hortensius R, de Gelder B, Schutter DJLG. When anger dominates the mind: Increased motor corticospinal excitability in the face of threat. Psychophysiology 2016; 53:1307-16. [PMID: 27325519 PMCID: PMC5113684 DOI: 10.1111/psyp.12685] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 05/10/2016] [Indexed: 02/06/2023]
Abstract
Threat demands fast and adaptive reactions that are manifested at the physiological, behavioral, and phenomenological level and are responsive to the direction of threat and its severity for the individual. Here, we investigated the effects of threat directed toward or away from the observer on motor corticospinal excitability and explicit recognition. Sixteen healthy right‐handed volunteers completed a transcranial magnetic stimulation (TMS) task and a separate three‐alternative forced‐choice emotion recognition task. Single‐pulse TMS to the left primary motor cortex was applied to measure motor evoked potentials from the right abductor pollicis brevis in response to dynamic angry, fearful, and neutral bodily expressions with blurred faces directed toward or away from the observer. Results showed that motor corticospinal excitability increased independent of direction of anger compared with fear and neutral. In contrast, anger was better recognized when directed toward the observer compared with when directed away from the observer, while the opposite pattern was found for fear. The present results provide evidence for the differential effects of threat direction on explicit recognition and motor corticospinal excitability. In the face of threat, motor corticospinal excitability increases independently of the direction of anger, indicative of the importance of more automatic reactions to threat.
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Affiliation(s)
- Ruud Hortensius
- Brain and Emotion Laboratory, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands.,Cognitive and Affective Neuroscience Laboratory, Department of Medical and Clinical Psychology, Tilburg School of Social and Behavioral Sciences, Tilburg University, Tilburg, The Netherlands.,Department of Psychiatry and Mental Health, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Beatrice de Gelder
- Brain and Emotion Laboratory, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands.,Department of Psychiatry and Mental Health, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Dennis J L G Schutter
- Donders Institute of Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
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110
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Kothari M, Baad-Hansen L, Svensson P. Bilateral sensory deprivation of trigeminal afferent fibres on corticomotor control of human tongue musculature: a preliminary study. J Oral Rehabil 2016; 43:656-61. [PMID: 27265155 DOI: 10.1111/joor.12414] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2016] [Indexed: 12/01/2022]
Abstract
Transcranial magnetic stimulation (TMS) has demonstrated changes in motor evoked potentials (MEPs) in human limb muscles following modulation of sensory afferent inputs. The aim of this study was to determine whether bilateral local anaesthesia (LA) of the lingual nerve affects the excitability of the tongue motor cortex (MI) as measured by TMS. The effect on MEPs after bilateral LA of the lingual nerve was studied, while the first dorsal interosseous (FDI) muscle served as a control in ten healthy participants. MEPs were measured on the right side of the tongue dorsum in four different conditions: (i) immediately prior to anaesthesia (baseline), (ii) during bilateral LA block of the lingual nerve, (iii) after anaesthesia had subjectively subsided (recovery) and (iv) 3 h after bilateral lingual block injection. MEPs were assessed using stimulus-response curves in steps of 10% of motor threshold (T). Eight stimuli were given at each stimulus level. The amplitudes of the tongue MEPs were significantly influenced by the stimulus intensity (P < 0·001) but not by condition (P = 0·186). However, post hoc tests showed that MEPS were statistically significantly higher during bilateral LA block condition compared with baseline at T + 40%, T + 50% and T + 60% (P < 0·028) and also compared with recovery at T + 60% (P = 0·010) as well as at 3 h after injection at T + 50% and T + 60% (P < 0·029). Bilateral LA block of the lingual nerve seems to be associated with a facilitation of the corticomotor pathways related to the tongue musculature.
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Affiliation(s)
- M Kothari
- Hammel Neurorehabilitation Centre and University Research Clinic, Aarhus University, Hammel, Denmark
| | - L Baad-Hansen
- Section of Orofacial Pain and Jaw Function, Institute of Odontology and Oral Health, Aarhus University, Aarhus, Denmark.,Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark
| | - P Svensson
- Section of Orofacial Pain and Jaw Function, Institute of Odontology and Oral Health, Aarhus University, Aarhus, Denmark.,Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark
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111
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Raco V, Bauer R, Tharsan S, Gharabaghi A. Combining TMS and tACS for Closed-Loop Phase-Dependent Modulation of Corticospinal Excitability: A Feasibility Study. Front Cell Neurosci 2016; 10:143. [PMID: 27252625 PMCID: PMC4879130 DOI: 10.3389/fncel.2016.00143] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/12/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The corticospinal excitability indexed by motor evoked potentials (MEPs) following transcranial magnetic stimulation (TMS) of the sensorimotor cortex is characterized by large variability. The instantaneous phase of cortical oscillations at the time of the stimulation has been suggested as a possible source of this variability. To explore this hypothesis, a specific phase needs to be targeted by TMS pulses with high temporal precision. OBJECTIVE The aim of this feasibility study was to introduce a methodology capable of exploring the effects of phase-dependent stimulation by the concurrent application of alternating current stimulation (tACS) and TMS. METHOD We applied online calibration and closed-loop TMS to target four specific phases (0°, 90°, 180° and 270°) of simultaneous 20 Hz tACS over the primary motor cortex (M1) of seven healthy subjects. RESULT The integrated stimulation system was capable of hitting the target phase with high precision (SD ± 2.05 ms, i.e., ± 14.45°) inducing phase-dependent MEP modulation with a phase lag (CI95% = -40.37° to -99.61°) which was stable across subjects (p = 0.001). CONCLUSION The combination of different neuromodulation techniques facilitates highly specific brain state-dependent stimulation, and may constitute a valuable tool for exploring the physiological and therapeutic effect of phase-dependent stimulation, e.g., in the context of neurorehabilitation.
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Affiliation(s)
- Valerio Raco
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tübingen Baden-Württemberg, Germany
| | - Robert Bauer
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tübingen Baden-Württemberg, Germany
| | - Srikandarajah Tharsan
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tübingen Baden-Württemberg, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tübingen Baden-Württemberg, Germany
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112
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Tremblay S, Lafleur LP, Proulx S, Beaulé V, Latulipe-Loiselle A, Doyon J, Marjańska M, Théoret H. The effects of bi-hemispheric M1-M1 transcranial direct current stimulation on primary motor cortex neurophysiology and metabolite concentration. Restor Neurol Neurosci 2016; 34:587-602. [PMID: 27232951 PMCID: PMC9924828 DOI: 10.3233/rnn-150569] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE The aim of the present study was to assess, in healthy individuals, the impact of M1-M1 tDCS on primary motor cortex excitability using transcranial magnetic stimulation and sensorimotor metabolite concentration using 1H-MRS. METHODS For both experiments, each participant received the three following interventions (20 min tDCS, 1 mA): left-anodal/right-cathodal, left-cathodal/right-anodal, sham. The effects of tDCS were assessed via motor evoked potentials (experiment 1) and metabolite concentrations (experiment 2) immediately after and 12 minutes following the end of stimulation and compared to baseline measurement. RESULTS No effect of M1-M1 tDCS on corticospinal excitability was found. Similarly, M1-M1 tDCS did not significantly modulate metabolite concentrations. High inter-subject variability was noted. Response rate analysis showed a tendency towards inhibition following left-anodal/right-cathodal tDCS in 50% of participants and increased GABA levels in 45% of participants. CONCLUSION In line with recent studies showing important inter-subject variability following M1-supraorbital tDCS, the present data show that M1-M1 stimulation is also associated with large response variability. The absence of significant effects suggests that current measures may lack sensitivity to assess changes in M1 neurophysiology and metabolism associated with M1-M1 tDCS.
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Affiliation(s)
- Sara Tremblay
- Département de psychologie, Université de Montréal, Montréal, Canada,Centre de recherche du Centre Hospitalier Universitaire de l’Hôpital Sainte-Justine, Montréal, Canada
| | - Louis-Philippe Lafleur
- Département de psychologie, Université de Montréal, Montréal, Canada,Centre de recherche du Centre Hospitalier Universitaire de l’Hôpital Sainte-Justine, Montréal, Canada
| | - Sébastien Proulx
- Unité de Neuroimagerie Fonctionnelle, Centre de recherche de l’Institut Universitaire de Gériatrie de Montréal, Canada,McGill University, Montréal, Canada
| | - Vincent Beaulé
- Département de psychologie, Université de Montréal, Montréal, Canada,Centre de recherche du Centre Hospitalier Universitaire de l’Hôpital Sainte-Justine, Montréal, Canada
| | | | - Julien Doyon
- Unité de Neuroimagerie Fonctionnelle, Centre de recherche de l’Institut Universitaire de Gériatrie de Montréal, Canada
| | - Małgorzata Marjańska
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, USA
| | - Hugo Théoret
- Département de psychologie, Université de Montréal, Montréal, Canada,Centre de recherche du Centre Hospitalier Universitaire de l’Hôpital Sainte-Justine, Montréal, Canada
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113
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Troni W, Melillo F, Bertolotto A, Malucchi S, Capobianco M, Sperli F, Di Sapio A. Normative Values for Intertrial Variability of Motor Responses to Nerve Root and Transcranial Stimulation: A Condition for Follow-Up Studies in Individual Subjects. PLoS One 2016; 11:e0155268. [PMID: 27182973 PMCID: PMC4868303 DOI: 10.1371/journal.pone.0155268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 04/11/2016] [Indexed: 11/19/2022] Open
Abstract
Objective Intertrial variability (ITV) of motor responses to peripheral (CMAP) and transcranial (MEP) stimulation prevents their use in follow-up studies. Our purpose was to develop strategies to reduce and measure CMAP and MEP ITV to guide long-term monitoring of conduction slowing and conduction failure of peripheral and central motor pathway in the individual patient. Methods Maximal compound muscle action potentials to High Voltage Electrical Stimulation (HVES) of lumbo-sacral nerve roots (r-CMAP) and activated, averaged motor evoked potentials (MEPs) to Transcranial Magnetic Stimulation (TMS) using double cone coil were recorded from 10 proximal and distal muscle districts of lower limbs. The procedure was repeated twice, 1–2 days apart, in 30 subjects, including healthy volunteers and clinically stable multiple sclerosis patients, using constant stimulating and recording sites and adopting a standardized procedure of voluntary activation. ITV for latency and area indexes and for the ratio between MEP and r-CMAP areas (a-Ratio) was expressed as Relative Intertrial Variation (RIV, 5th-95th percentile). As an inverse correlation between the size of area and ITV was found, raw ITV values were normalized as a function of area to make them comparable with one another. Results All RIV values for latencies were significantly below the optimum threshold of ± 10%, with the exception of r-CMAP latencies recorded from Vastus Lateralis muscle. RIVs for a-Ratio, the most important index of central conduction failure, ranged from a maximum of -25.3% to +32.2% (Vastus Medialis) to a minimum of -15.0% to + 17.4% (Flexor Hallucis Brevis). Conclusions The described procedure represents an effort to lower as much as possible variability of motor responses in serial recording; the reported ITV normative values are the necessary premise to detect significant changes of motor conduction slowing and failure in the individual patient in follow-up studies.
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Affiliation(s)
- Walter Troni
- Service of Neurology and Clinical Neurophysiology, Clinica Fornaca di Sessant, Turin, Italy
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
- * E-mail:
| | - Federica Melillo
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
| | - Antonio Bertolotto
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
| | - Simona Malucchi
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
| | - Marco Capobianco
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
| | - Francesca Sperli
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
| | - Alessia Di Sapio
- 2nd Department of Neurology, Multiple Sclerosis Regional Centre, San Luigi Gonzaga Hospital, Orbassano, Italy
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114
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Massé-Alarie H, Beaulieu LD, Preuss R, Schneider C. Influence of paravertebral muscles training on brain plasticity and postural control in chronic low back pain. Scand J Pain 2016; 12:74-83. [PMID: 28850499 DOI: 10.1016/j.sjpain.2016.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/19/2016] [Accepted: 03/17/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE Isometric activation (ISOM) of deep multifidi muscles (MF) can influence postural adjustments and primary motor cortex (M1) function in chronic low back pain (CLBP). In order to better understand how ISOM impacts on CLBP condition, the present study contrasted ISOM after-effects on M1 function, MF postural activation and pain with another training, the global activation of paravertebral muscles (GLOB, hip extension). The main objective of this study was to compare the effects of ISOM and GLOB (3-week training each) on MF postural activation and M1 function in a CLBP population. METHODS Twenty-four people with CLBP were randomly allocated to ISOM and GLOB groups for a 3-week daily practice. Pre/post-training after-effects were assessed by the onset of superficial MF (MF-S) activation during ballistic limb movements (bilateral shoulder flexion in standing; unilateral hip extension in prine lying), MF-S corticomotor control tested by transcranial magnetic stimulation of M1, and assessment of pain, kinesiophobia and disability by standardized questionnaires. RESULTS Both ISOM and GLOB improved pain and disability. However, only ISOM influenced M1 function (decreased corticospinal excitability and increased intracortical inhibition), fastened MF-S postural activation and decreased kinesiophobia. CONCLUSIONS Changes of corticospinal excitability and of MF-S postural adjustments suggest that ISOM better influenced brain plasticity. Future studies should further test whether our novel findings relate to an influence of the exercises on the lumbopelvic control of different muscles and on cognitive function. Clinically, individual's evaluation remains warranted before prescribing one or the other of these two conventional exercises for reducing pain. IMPLICATIONS This original study presents how motor control exercises can influence brain plasticity and postural control in chronic low back pain. This knowledge will impact on the decision of clinicians to prescribe specific exercises with a view of improving motor control in this musculoskeletal condition.
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Affiliation(s)
- Hugo Massé-Alarie
- Research Center of CHU de Québec, Neuroscience Division, Clinical Neuroscience and Neurostimulation Laboratory, Quebec City, QC, Canada.
| | - Louis-David Beaulieu
- Research Center of CHU de Québec, Neuroscience Division, Clinical Neuroscience and Neurostimulation Laboratory, Quebec City, QC, Canada
| | - Richard Preuss
- McGill University, Constance-Lethbridge Rehabilitation Center-CRIR, Montreal, QC, Canada
| | - Cyril Schneider
- Research Center of CHU de Québec, Neuroscience Division, Clinical Neuroscience and Neurostimulation Laboratory, Quebec City, QC, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
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Royter V, Gharabaghi A. Brain State-Dependent Closed-Loop Modulation of Paired Associative Stimulation Controlled by Sensorimotor Desynchronization. Front Cell Neurosci 2016; 10:115. [PMID: 27242429 PMCID: PMC4861730 DOI: 10.3389/fncel.2016.00115] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 04/20/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Pairing peripheral electrical stimulation (ES) and transcranial magnetic stimulation (TMS) increases corticospinal excitability when applied with a specific temporal pattern. When the two stimulation techniques are applied separately, motor imagery (MI)-related oscillatory modulation amplifies both ES-related cortical effects-sensorimotor event-related desynchronization (ERD), and TMS-induced peripheral responses-motor-evoked potentials (MEP). However, the influence of brain self-regulation on the associative pairing of these stimulation techniques is still unclear. OBJECTIVE The aim of this pilot study was to investigate the effects of MI-related ERD during associative ES and TMS on subsequent corticospinal excitability. METHOD The paired application of functional electrical stimulation (FES) of the extensor digitorum communis (EDC) muscle and subsequent single-pulse TMS (110% resting motor threshold (RMT)) of the contralateral primary motor cortex (M1) was controlled by beta-band (16-22 Hz) ERD during MI of finger extension and applied within a brain-machine interface environment in six healthy subjects. Neural correlates were probed by acquiring the stimulus-response curve (SRC) of both MEP peak-to-peak amplitude and area under the curve (AUC) before and after the intervention. RESULT The application of approximately 150 pairs of associative FES and TMS resulted in a significant increase of MEP amplitudes and AUC, indicating that the induced increase of corticospinal excitability was mediated by the recruitment of additional neuronal pools. MEP increases were brain state-dependent and correlated with beta-band ERD, but not with the background EDC muscle activity; this finding was independent of the FES intensity applied. CONCLUSION These results could be relevant for developing closed-loop therapeutic approaches such as the application of brain state-dependent, paired associative stimulation (PAS) in the context of neurorehabilitation.
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Affiliation(s)
- Vladislav Royter
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
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Kraus D, Naros G, Bauer R, Khademi F, Leão MT, Ziemann U, Gharabaghi A. Brain State-Dependent Transcranial Magnetic Closed-Loop Stimulation Controlled by Sensorimotor Desynchronization Induces Robust Increase of Corticospinal Excitability. Brain Stimul 2016; 9:415-424. [DOI: 10.1016/j.brs.2016.02.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 02/01/2016] [Accepted: 02/10/2016] [Indexed: 10/22/2022] Open
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Chang WH, Fried PJ, Saxena S, Jannati A, Gomes-Osman J, Kim YH, Pascual-Leone A. Optimal number of pulses as outcome measures of neuronavigated transcranial magnetic stimulation. Clin Neurophysiol 2016; 127:2892-2897. [PMID: 27156431 DOI: 10.1016/j.clinph.2016.04.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 03/24/2016] [Accepted: 04/01/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Identify the optimal number of pulses necessary to achieve reliable measures of motor evoked potentials (MEPs) in transcranial magnetic stimulation (TMS) studies. METHODS Retrospective data was obtained from 54 healthy volunteers (30 men, mean age 61.7±13.1years) who as part of prior studies had completed three blocks of 30 consecutive TMS stimuli using neuronavigation. Data from four protocols were assessed: single-pulse TMS for measures of amplitude and latency of MEPs; paired-pulse TMS for short-interval intracortical inhibition (sICI) and intracortical facilitation (ICF); and single-pulse TMS to assess the effects of intermittent theta burst stimulation (iTBS). Two statistical methods were used: an internal consistency analysis and probability of inclusion in the 95% confidence interval (CI) around the mean MEPs amplitude. RESULTS For single-pulse TMS, the minimum number of pulses needed to achieve reliable amplitude and latency MEPs measures was 21 and 23, respectively. For paired-pulse TMS, the minimum number of pulses needed to achieve reliable sICI and ICF measures was 20 and 25, respectively. Finally, the minimum number of pulses needed to achieve reliable amplitude and latency MEPs measures after iTBS was 22 and 23, respectively. CONCLUSIONS This study provides guidelines regarding the minimum number of pulses needed to achieve reliable MEPs measurements in various study protocols using neuronavigated TMS. SIGNIFICANCE Results from this study have the potential to increase the reliability and quality of future neuronavigated TMS studies.
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Affiliation(s)
- Won Hyuk Chang
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA; Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Peter J Fried
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Sadhvi Saxena
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Ali Jannati
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Joyce Gomes-Osman
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Yun-Hee Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Health Science and Technology, Department of Medical Device Management & Research, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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Goldsworthy M, Hordacre B, Ridding M. Minimum number of trials required for within- and between-session reliability of TMS measures of corticospinal excitability. Neuroscience 2016; 320:205-9. [DOI: 10.1016/j.neuroscience.2016.02.012] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 11/30/2022]
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Pearcey GE, Bradbury-Squires DJ, Monks M, Philpott D, Power KE, Button DC. Arm-cycling sprints induce neuromuscular fatigue of the elbow flexors and alter corticospinal excitability of the biceps brachii. Appl Physiol Nutr Metab 2016; 41:199-209. [DOI: 10.1139/apnm-2015-0438] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We examined the effects of arm-cycling sprints on maximal voluntary elbow flexion and corticospinal excitability of the biceps brachii. Recreationally trained athletes performed ten 10-s arm-cycling sprints interspersed with 150 s of rest in 2 separate experiments. In experiment A (n = 12), maximal voluntary contraction (MVC) force of the elbow flexors was measured at pre-sprint 1, post-sprint 5, and post-sprint 10. Participants received electrical motor point stimulation during and following the elbow flexor MVCs to estimate voluntary activation (VA). In experiment B (n = 7 participants from experiment A), supraspinal and spinal excitability of the biceps brachii were measured via transcranial magnetic and transmastoid electrical stimulation that produced motor evoked potentials (MEPs) and cervicomedullary motor evoked potentials (CMEPs), respectively, during a 5% isometric MVC at pre-sprint 1, post-sprint 1, post-sprint 5, and post-sprint 10. In experiment A, mean power output, MVC force, potentiated twitch force, and VA decreased 13.1% (p < 0.001), 8.7% (p = 0.036), 27.6% (p = 0.003), and 5.6% (p = 0.037), respectively, from pre-sprint 1 to post-sprint 10. In experiment B, (i) MEPs decreased 42.1% (p = 0.002) from pre-sprint 1 to post-sprint 5 and increased 40.1% (p = 0.038) from post-sprint 5 to post-sprint 10 and (ii) CMEPs increased 28.5% (p = 0.045) from post-sprint 1 to post-sprint 10. Overall, arm-cycling sprints caused neuromuscular fatigue of the elbow flexors, which corresponded with decreased supraspinal and increased spinal excitability of the biceps brachii. The different post-sprint effects on supraspinal and spinal excitability may illustrate an inhibitory effect on supraspinal drive that reduces motor output and, therefore, decreases arm-cycling sprint performance.
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Affiliation(s)
- Gregory E.P. Pearcey
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | | | - Michael Monks
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Devin Philpott
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Kevin E. Power
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Duane C. Button
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
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120
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Modification of motor cortex excitability during muscle relaxation in motor learning. Behav Brain Res 2016; 296:78-84. [DOI: 10.1016/j.bbr.2015.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/05/2015] [Accepted: 09/01/2015] [Indexed: 11/23/2022]
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121
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O'Leary TJ, Morris MG, Collett J, Howells K. Central and peripheral fatigue following non-exhaustive and exhaustive exercise of disparate metabolic demands. Scand J Med Sci Sports 2015; 26:1287-1300. [DOI: 10.1111/sms.12582] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2015] [Indexed: 11/29/2022]
Affiliation(s)
- T. J. O'Leary
- Department of Sport and Health Sciences; Oxford Brookes University; Oxford UK
| | - M. G. Morris
- Department of Sport and Health Sciences; Oxford Brookes University; Oxford UK
| | - J. Collett
- Department of Sport and Health Sciences; Oxford Brookes University; Oxford UK
| | - K. Howells
- Department of Sport and Health Sciences; Oxford Brookes University; Oxford UK
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122
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O'Leary TJ, Morris MG, Collett J, Howells K. Reliability of single and paired-pulse transcranial magnetic stimulation in the vastus lateralis muscle. Muscle Nerve 2015; 52:605-15. [PMID: 25620286 DOI: 10.1002/mus.24584] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/14/2015] [Accepted: 01/19/2015] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Transcranial magnetic stimulation (TMS) is an important tool to examine neurological pathologies, movement disorders, and central nervous system responses to exercise, fatigue, and training. The reliability has not been examined in a functional locomotor knee extensor muscle. METHODS Within- (n = 10) and between-day (n = 16) reliability of single and paired-paired pulse TMS was examined from the active vastus lateralis. RESULTS Motor evoked potential amplitude and cortical silent period duration showed good within- and between-day reliability (intraclass correlation coefficient [ICC] ≥ 0.82). Short- and long-interval intracortical inhibition (SICI and LICI, respectively) demonstrated good within-day reliability (ICC ≥ 0.84). SICI had moderate to good between-day reliability (ICC ≥ 0.67), but LICI was not repeatable (ICC = 0.47). Intracortical facilitation showed moderate to good within-day reliability (ICC ≥ 0.73) but poor to moderate reliability between days (ICC ≥ 0.51). CONCLUSIONS TMS can reliably assess cortical function in a knee extensor muscle. This may be useful to examine neurological disorders that affect locomotion.
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Affiliation(s)
- Thomas J O'Leary
- Department of Sport and Health Sciences, Oxford Brookes University, Gipsy Lane, Oxford, Oxon, OX3 0BP, United Kingdom
| | - Martyn G Morris
- Department of Sport and Health Sciences, Oxford Brookes University, Gipsy Lane, Oxford, Oxon, OX3 0BP, United Kingdom
| | - Johnny Collett
- Department of Sport and Health Sciences, Oxford Brookes University, Gipsy Lane, Oxford, Oxon, OX3 0BP, United Kingdom
| | - Ken Howells
- Department of Sport and Health Sciences, Oxford Brookes University, Gipsy Lane, Oxford, Oxon, OX3 0BP, United Kingdom
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123
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Li LM, Uehara K, Hanakawa T. The contribution of interindividual factors to variability of response in transcranial direct current stimulation studies. Front Cell Neurosci 2015; 9:181. [PMID: 26029052 PMCID: PMC4428123 DOI: 10.3389/fncel.2015.00181] [Citation(s) in RCA: 282] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 04/25/2015] [Indexed: 01/08/2023] Open
Abstract
There has been an explosion of research using transcranial direct current stimulation (tDCS) for investigating and modulating human cognitive and motor function in healthy populations. It has also been used in many studies seeking to improve deficits in disease populations. With the slew of studies reporting “promising results” for everything from motor recovery after stroke to boosting memory function, one could be easily seduced by the idea of tDCS being the next panacea for all neurological ills. However, huge variability exists in the reported effects of tDCS, with great variability in the effect sizes and even contradictory results reported. In this review, we consider the interindividual factors that may contribute to this variability. In particular, we discuss the importance of baseline neuronal state and features, anatomy, age and the inherent variability in the injured brain. We additionally consider how interindividual variability affects the results of motor-evoked potential (MEP) testing with transcranial magnetic stimulation (TMS), which, in turn, can lead to apparent variability in response to tDCS in motor studies.
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Affiliation(s)
- Lucia M Li
- Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry Tokyo, Japan ; Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Restorative Neurosciences, Imperial College London London, UK
| | - Kazumasa Uehara
- Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry Tokyo, Japan ; Research Fellow of the Japan Society for the Promotion of Science Tokyo Japan
| | - Takashi Hanakawa
- Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry Tokyo, Japan
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Leon-Sarmiento FE, Rizzo-Sierra CV, Leon-Ariza JS, Leon-Ariza DS, Sobota R, Prada DG. A new neurometric dissection of the area-under-curve-associated jiggle of the motor evoked potential induced by transcranial magnetic stimulation. Physiol Behav 2015; 141:111-9. [DOI: 10.1016/j.physbeh.2015.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 01/09/2015] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
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125
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Leonard CT, Danna-dos-Santos A, Peters C, Moore M. Corticomotor excitability changes during mirrored or asynergistic wrist movements. Behav Brain Res 2015; 281:199-207. [DOI: 10.1016/j.bbr.2014.12.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
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126
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Neural summation in human motor cortex by subthreshold transcranial magnetic stimulations. Exp Brain Res 2014; 233:671-7. [PMID: 25399245 DOI: 10.1007/s00221-014-4146-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
Abstract
Integration of diverse synaptic inputs is a basic neuronal operation that relies on many neurocomputational principles, one of which is neural summation. However, we lack empirical understanding of neuronal summation in the human brains in vivo. Here, we explored the effect of neural summation on the motor cortex using two subthreshold pulses of transcranial magnetic stimulation (TMS), each with intensities ranging from 60 to 95% of the resting motor threshold (RMT) and interstimulus interval (ISI) varying from 1 to 25 ms. We found that two subthreshold TMS pulses can produce suprathreshold motor response when ISIs were less than 10 ms, most prominent at 1, 1.5 and 3 ms. This facilitatory, above-threshold response was evident when the intensity of the subthreshold pulses was above 80% of RMT but was absent as the intensity was 70% or below. Modeling of the summation data across intensity suggested that they followed an exponential function with excellent model fitting. Understanding the constraints for inducing summation of subthreshold stimulations to generate above-threshold response may have implications in modeling neural operations and potential clinical applications.
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127
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Solopova I, Selionov V, Kazennikov O, Ivanenko Y. Effects of transcranial magnetic stimulation during voluntary and non-voluntary stepping movements in humans. Neurosci Lett 2014; 579:64-9. [DOI: 10.1016/j.neulet.2014.07.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/06/2014] [Accepted: 07/08/2014] [Indexed: 01/01/2023]
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128
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Schmidt S, Bathe-Peters R, Fleischmann R, Rönnefarth M, Scholz M, Brandt SA. Nonphysiological factors in navigated TMS studies; confounding covariates and valid intracortical estimates. Hum Brain Mapp 2014; 36:40-9. [PMID: 25168635 DOI: 10.1002/hbm.22611] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 08/06/2014] [Accepted: 08/06/2014] [Indexed: 11/09/2022] Open
Abstract
UNLABELLED Brain stimulation is used to induce transient alterations of neural excitability to probe or modify brain function. For example, single-pulse transcranial magnetic stimulation (TMS) of the motor cortex can probe corticospinal excitability (CSE). Yet, CSE measurements are confounded by a high level of variability. This variability is due to physical and physiological factors. Navigated TMS (nTMS) systems can record physical parameters of the TMS coil (tilt, location, and orientation) and some also estimate intracortical electric fields (EFs) on a trial-by-trial basis. Thus, these parameters can be partitioned with stepwise regression. PURPOSE The primary objective was to dissociate variance due to physical parameters from variance due to physiological factors for CSE estimates. The secondary objective was to establish the predictive validity of EF estimates from spherical head models. HYPOTHESIS Variability of physical parameters of TMS predicts CSE variability. METHODS Event-related measurements of physical parameters were analyzed in stepwise regression. Partitioned parameter variance and predictive validity were compared for a target-controlled and a nontarget-controlled experiment. A control experiment (preinnervation) confirmed the validity of linear data analysis. A bias-free model quantified the effect of divergence from optimum. RESULTS Partitioning physical parameter variance reduces CSE variability. EF estimates from spherical models were valid. Post hoc analyses showed that even small physical fluctuations can confound the statistical comparison of CSE measurements. CONCLUSIONS It is necessary to partition physical and physiological variance in TMS studies to make confounded data interpretable. The spatial resolution of nTMS is <5 mm and the EF-estimates are valid.
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Affiliation(s)
- Sein Schmidt
- Vision & Motor Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, Berlin, Germany
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Macrae PR, Jones RD, Huckabee ML. The effect of swallowing treatments on corticobulbar excitability: a review of transcranial magnetic stimulation induced motor evoked potentials. J Neurosci Methods 2014; 233:89-98. [PMID: 24932964 DOI: 10.1016/j.jneumeth.2014.06.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 06/07/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
Abstract
Transcranial magnetic stimulation (TMS) has been used extensively as a method of investigating the corticomotor physiology of many motor tasks, including healthy and disordered swallowing. Changes in excitability of cortical projections to various swallowing muscles have been documented in response to treatments with TMS induced motor evoked potentials (MEPs). These studies have provided valuable insight into CNS response to swallowing impairment, and more importantly, the adaptations associated with functional recovery. However, unique obstacles are presented when investigating corticobulbar neurophysiology associated with the complex task of swallowing. Stringent methodological control and supplementary outcome measures are required to ensure robust and clinically applicable findings. This article offers a tutorial for the researcher who may be considering the use of TMS for investigating changes in cortical excitability associated with various swallowing paradigms. Included is a review of the mechanisms of TMS and what can be measured with this technique, a summary of existing research using MEPs to investigate swallowing, a review of methodological factors that may influence outcomes, and proposed directions for new areas of research.
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Affiliation(s)
- Phoebe R Macrae
- New Zealand Brain Research Institute, 66 Stewart Street, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
| | - Richard D Jones
- New Zealand Brain Research Institute, 66 Stewart Street, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Private Bag 4800, Christchurch, New Zealand; Department of Medicine, University of Otago, Private Bag 4710, Christchurch, New Zealand; Department of Medical Physics and Bioengineering, Canterbury District Health Board, Private Bag 4710, Christchurch, New Zealand.
| | - Maggie-Lee Huckabee
- New Zealand Brain Research Institute, 66 Stewart Street, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
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130
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Liu H, Au-Yeung SSY. Reliability of transcranial magnetic stimulation induced corticomotor excitability measurements for a hand muscle in healthy and chronic stroke subjects. J Neurol Sci 2014; 341:105-9. [PMID: 24792099 DOI: 10.1016/j.jns.2014.04.012] [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: 09/08/2013] [Revised: 04/07/2014] [Accepted: 04/08/2014] [Indexed: 11/30/2022]
Abstract
Transcranial magnetic stimulation (TMS) has been used to evaluate neuroplastic changes in the brain in clinical trials. The purpose of this study was to establish the test-retest reliability of 4 TMS measures of corticomotor excitability - (1) resting motor threshold, (2) slope of input-output curve, (3) peak motor evoked potential amplitude, and (4) cortical silent period duration for the corticospinal projections to the first dorsal interosseous of the contralateral hand. Fourteen healthy subjects (mean age 27.4 years) and 27 subjects with stroke-induced upper limb hemiparesis (mean age 61.3 years) completed 2 repeated sessions of assessment of 1 week apart. Good to excellent test-retest reliability of the TMS measurements was confirmed in the stroke subjects for both hemispheres with the ICC ≥ 0.88. Measurement reliability was good (ICC ≥ 0.75) for the 4 outcome measures in healthy subjects. Contrary to the similarity in standard error of measurements in both hemispheres for outcome measures (1) to (3) in the stroke subjects, that of the cortical silent period duration was larger in magnitude in the lesioned hemisphere. The test-retest reliability coefficients determined for the four corticomotor excitability measurements allowed the estimation of 95% minimal detectable changes of these outcome variables for the respective subject group in future clinical trials.
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Affiliation(s)
- Hao Liu
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong; Guangdong Provincial Work Injury Rehabilitation Hospital, Guangzhou, China
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Buharin VE, Butler AJ, Shinohara M. Motor cortical disinhibition with baroreceptor unloading induced by orthostatic stress. J Neurophysiol 2014; 111:2656-64. [PMID: 24671536 DOI: 10.1152/jn.00778.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unloading of the baroreceptors due to orthostatic stress increases corticospinal excitability. The purpose of this study was to examine the effects of baroreceptor unloading due to orthostatic stress on intracortical excitatory and inhibitory pathways in the motor cortex. With transcranial magnetic stimulation, measures of intracortical excitability for a hand muscle were tested on 2 days in healthy young adults. Lower body negative pressure (LBNP) of 40 mmHg was applied during one of the days and not during the Control day. During application of LBNP heart rate and the low-frequency component of heart rate variability increased, while mean arterial blood pressure was maintained. In the resting state, LBNP decreased short-interval intracortical inhibition (SICI) and had no effect on intracortical facilitation (ICF) or short-interval intracortical facilitation (SICF) compared with the Control day. During isometric contraction, no effects of LBNP were observed on tested measures of intracortical excitability including SICI, SICF, and cortical silent period. It was concluded that baroreceptor unloading due to orthostatic stress results in diminished intracortical inhibition, at least in the resting muscle.
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Affiliation(s)
- Vasiliy E Buharin
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia
| | - Andrew J Butler
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia; Department of Physical Therapy, Georgia State University, Atlanta, Georgia; and Rehabilitation R&D Center of Excellence, Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia
| | - Minoru Shinohara
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia; Rehabilitation R&D Center of Excellence, Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia
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132
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Rittig-Rasmussen B, Kasch H, Fuglsang-Frederiksen A, Svensson P, Jensen T. Effect of training on corticomotor excitability in clinical neck pain. Eur J Pain 2014; 18:1207-16. [DOI: 10.1002/j.1532-2149.2014.487.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2014] [Indexed: 12/14/2022]
Affiliation(s)
| | - H. Kasch
- Department of Neurology; Aarhus University Hospital; Denmark
| | | | - P. Svensson
- Clinical Oral Physiology; Department of Dentistry; Aarhus University; Denmark
- Department of Oral Maxillofacial Surgery; Aarhus University Hospital; Denmark
| | - T.S. Jensen
- Danish Pain Research Center; Aarhus University Hospital; Denmark
- Department of Neurology; Aarhus University Hospital; Denmark
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133
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Temesi J, Gruet M, Rupp T, Verges S, Millet GY. Resting and active motor thresholds versus stimulus-response curves to determine transcranial magnetic stimulation intensity in quadriceps femoris. J Neuroeng Rehabil 2014; 11:40. [PMID: 24655366 PMCID: PMC3976163 DOI: 10.1186/1743-0003-11-40] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 03/04/2014] [Indexed: 01/07/2023] Open
Abstract
Background Transcranial magnetic stimulation (TMS) is a widely-used investigative technique in motor cortical evaluation. Recently, there has been a surge in TMS studies evaluating lower-limb fatigue. TMS intensity of 120-130% resting motor threshold (RMT) and 120% active motor threshold (AMT) and TMS intensity determined using stimulus–response curves during muscular contraction have been used in these studies. With the expansion of fatigue research in locomotion, the quadriceps femoris is increasingly of interest. It is important to select a stimulus intensity appropriate to evaluate the variables, including voluntary activation, being measured in this functionally important muscle group. This study assessed whether selected quadriceps TMS stimulus intensity determined by frequently employed methods is similar between methods and muscles. Methods Stimulus intensity in vastus lateralis, rectus femoris and vastus medialis muscles was determined by RMT, AMT (i.e. during brief voluntary contractions at 10% maximal voluntary force, MVC) and maximal motor-evoked potential (MEP) amplitude from stimulus–response curves during brief voluntary contractions at 10, 20 and 50% MVC at different stimulus intensities. Results Stimulus intensity determined from a 10% MVC stimulus–response curve and at 120 and 130% RMT was higher than stimulus intensity at 120% AMT (lowest) and from a 50% MVC stimulus–response curve (p < 0.05). Stimulus intensity from a 20% MVC stimulus–response curve was similar to 120% RMT and 50% MVC stimulus–response curve. Mean stimulus intensity for stimulus–response curves at 10, 20 and 50% MVC corresponded to approximately 135, 115 and 100% RMT and 180, 155 and 130% AMT, respectively. Selected stimulus intensity was similar between muscles for all methods (p > 0.05). Conclusions Similar optimal stimulus intensity and maximal MEP amplitudes at 20 and 50% MVC and the minimal risk of residual fatigue at 20% MVC suggest that a 20% MVC stimulus–response curve is appropriate for determining TMS stimulus intensity in the quadriceps femoris. The higher selected stimulus intensities at 120-130% RMT have the potential to cause increased coactivation and discomfort and the lower stimulus intensity at 120% AMT may underestimate evoked responses. One muscle may also act as a surrogate in determining optimal quadriceps femoris stimulation intensity.
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Affiliation(s)
| | | | | | | | - Guillaume Y Millet
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, Saint-Etienne F-42023, France.
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134
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Sloan TB, Toleikis JR, Toleikis SC, Koht A. Intraoperative neurophysiological monitoring during spine surgery with total intravenous anesthesia or balanced anesthesia with 3 % desflurane. J Clin Monit Comput 2014; 29:77-85. [DOI: 10.1007/s10877-014-9571-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 03/12/2014] [Indexed: 10/25/2022]
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135
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Cuypers K, Thijs H, Meesen RLJ. Optimization of the transcranial magnetic stimulation protocol by defining a reliable estimate for corticospinal excitability. PLoS One 2014; 9:e86380. [PMID: 24475111 PMCID: PMC3901672 DOI: 10.1371/journal.pone.0086380] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 12/11/2013] [Indexed: 11/19/2022] Open
Abstract
The goal of this study was to optimize the transcranial magnetic stimulation (TMS) protocol for acquiring a reliable estimate of corticospinal excitability (CSE) using single-pulse TMS. Moreover, the minimal number of stimuli required to obtain a reliable estimate of CSE was investigated. In addition, the effect of two frequently used stimulation intensities [110% relative to the resting motor threshold (rMT) and 120% rMT] and gender was evaluated. Thirty-six healthy young subjects (18 males and 18 females) participated in a double-blind crossover procedure. They received 2 blocks of 40 consecutive TMS stimuli at either 110% rMT or 120% rMT in a randomized order. Based upon our data, we advise that at least 30 consecutive stimuli are required to obtain the most reliable estimate for CSE. Stimulation intensity and gender had no significant influence on CSE estimation. In addition, our results revealed that for subjects with a higher rMT, fewer consecutive stimuli were required to reach a stable estimate of CSE. The current findings can be used to optimize the design of similar TMS experiments.
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Affiliation(s)
- Koen Cuypers
- REVAL Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
- Motor Control Laboratory, Research Center for Movement Control and Neuroplasticity, Department of Biomedical Kinesiology, Group Biomedical Sciences, K.U. Leuven, Heverlee, Belgium
| | - Herbert Thijs
- I-BioStat, Interuniversity Institute for Biostatistics and statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium
- I-BioStat, Interuniversity Institute for Biostatistics and statistical Bioinformatics, Leuven University, Leuven, Belgium
| | - Raf L. J. Meesen
- REVAL Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
- Motor Control Laboratory, Research Center for Movement Control and Neuroplasticity, Department of Biomedical Kinesiology, Group Biomedical Sciences, K.U. Leuven, Heverlee, Belgium
- * E-mail:
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136
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A new neurophysiological approach to assess central motor conduction damage to proximal and distal muscles of lower limbs. Clin Neurophysiol 2014; 125:133-41. [PMID: 23867064 DOI: 10.1016/j.clinph.2013.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/26/2013] [Accepted: 06/21/2013] [Indexed: 01/28/2023]
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137
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Hoffman L, Field-Fote E. Effects of practice combined with somatosensory or motor stimulation on hand function in persons with spinal cord injury. Top Spinal Cord Inj Rehabil 2013; 19:288-99. [PMID: 24244094 DOI: 10.1310/sci1904-288] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Individuals with chronic tetraplegia prioritize recovery of hand function as an important factor in improving their quality of life. Interventions that may improve hand function and increase corticomotor excitability are functional electrical stimulation (FES), somatosensory stimulation (SS), and task-oriented training. OBJECTIVE We compared functional and corticomotor outcomes in a control condition to changes associated with FES (triggered via electromygraphic signals) and with SS (constant trains), each combined with either unimanual or bimanual training. METHODS Using a randomized, clinical trial design, comparisons were made to a delayed intervention control group. Participants (n = 24) had chronic tetraplegia, with the ability to activate thenar muscles, and were randomly assigned to either the immediate intervention (intervention) or control/ delayed intervention groups. Primary analyses compared intervention (FES or SS) to control/delayed intervention. Secondary analyses compared subgroups of FES versus SS (regardless of uni- or bilateral training) and uni- versus bimanual training (regardless of stimulation type). Outcomes were assessed before and after the control and the intervention period. RESULTS Compared to control/delayed intervention, the intervention group had greater changes in unimanual function and corticomotor area, regardless of whether practice was combined with FES or with SS. Irrespective of stimulation type, the bimanual subgroups improved to a greater extent than the unimanual subgroups on the bimanual hand function test. CONCLUSIONS Hand training combined with either SS or FES was associated with improved hand use and corticomotor activity in persons with chronic tetraplegia. Both interventions appear to be equally effective.
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Affiliation(s)
- Larisa Hoffman
- School of Physical Therapy, Regis University , Denver, Colorado
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138
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Specific neck training induces sustained corticomotor hyperexcitability as assessed by motor evoked potentials. Spine (Phila Pa 1976) 2013; 38:E979-84. [PMID: 23609207 DOI: 10.1097/brs.0b013e3182975310] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Experimental investigation of short-term and long-term corticomotor effects of specific neck training, coordination training, and no training. OBJECTIVE To determine the effects of different training programs on the motor neurons controlling the neck muscles as well as the effects of training on muscle strength and muscle fatigue, and the correlations between corticomotor control and motor learning. SUMMARY OF BACKGROUND DATA Training is usually recommended for unspecific neck pain and consists of neck and upper body coordination, strengthening, and endurance exercises. However, it is unclear which type of training is the most effective. No studies have previously investigated the neural effect of neck training and the possible differential effect of specific versus coordination training on corticomotor control. METHODS Transcranial magnetic stimulation and electromyography were used to elicit and monitor motor evoked potentials (MEPs) from the trapezius and thumb muscles before and 30 minutes, 1 hour, and 7 days after training. Parameters measured were MEP amplitude, MEP latency, strength, learning effects, and muscle fatigue. RESULTS Only specific neck training yielded a 67% increase in MEP amplitudes for up to 7 days after training compared with baseline (P < 0.001). No significant changes were seen after coordination training, no training, and in the within-subject control muscle. The mean muscle strength increased immediately after specific neck training from 56.6 to 61 kg (P < 0.001). No subjective or objective measures of fatigue were observed. CONCLUSION Specific neck training induced a sustained hyperexcitability of motor neurons controlling the neck muscles compared with coordination training and controls. These findings may prove valuable in the process of developing more effective clinical training programs for unspecific neck pain.
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139
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Gruet M, Temesi J, Rupp T, Millet GY, Verges S. Effect of different approaches to target force on transcranial magnetic stimulation responses. Muscle Nerve 2013; 48:430-2. [DOI: 10.1002/mus.23786] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Mathieu Gruet
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| | - John Temesi
- Laboratoire LPE; Université de Lyon; Saint-Etienne France
| | - Thomas Rupp
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| | | | - Samuel Verges
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
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140
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Abstract
Task-evoked trial-by-trial variability is a ubiquitous property of neural responses, yet its functional role remains largely unclear. Recent work in nonhuman primates shows that the temporal structure of neural variability in several brain regions is task-related. For example, trial-by-trial variability in premotor cortex tracks motor preparation with increasingly consistent firing rates and thus a decline in variability before movement onset. However, whether noninvasive measures of the variability of population activity available from humans can similarly track the preparation of actions remains unknown. We tested this by using single-pulse transcranial magnetic stimulation (TMS) over primary motor cortex (M1) to measure corticospinal excitability (CSE) at different times during action preparation. First, we established the basic properties of intrinsic CSE variability at rest. Then, during the task, responses (left or right button presses) were either directly instructed (forced choice) or resulted from a value decision (choice). Before movement onset, we observed a temporally specific task-related decline in CSE variability contralateral to the responding hand. This decline was stronger in fast-response compared with slow-response trials, consistent with data in nonhuman primates. For the nonresponding hand, CSE variability also decreased, but only in choice trials, and earlier compared with the responding hand, possibly reflecting choice-specific suppression of unselected actions. These findings suggest that human CSE variability measured by TMS over M1 tracks the state of motor preparation, and may reflect the optimization of preparatory population activity. This provides novel avenues in humans to assess the dynamics of action preparation but also more complex processes, such as choice-to-action transformations.
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141
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Abstract
STUDY DESIGN Reliability study. OBJECTIVES To determine the feasibility and reliability of using transcranial magnetic stimulation (TMS) to assess corticomotor excitability (CE) of the gluteus maximus. BACKGROUND Sport-specific skill training targeting greater utilization of the gluteus maximus has been proposed as a method to reduce the incidence of noncontact knee injuries. The use of TMS to assess changes in CE may help to determine training-induced central mechanisms associated with gluteus maximus activation. METHODS Within- and between-day reliability was measured in 10 healthy adults. The CE was measured by stimulating the gluteus maximus ìhotspotî at 120% and 150% of motor threshold, while subjects performed a double-leg bridge. An intraclass correlation coefficient (model 2,1), standard error of measurement, and minimal detectable change were calculated to determine the within- and between-day reliability for the following TMS variables: peak-to-peak motor-evoked potential (MEP) amplitudes, cortical silent period, and MEP latency. RESULTS It is feasible to measure the CE of the gluteus maximus with TMS. The intraclass correlation coefficients for all TMS outcome measures ranged from 0.73 to 0.97. The ranges of minimal detectable change, with respect to mean values for each TMS variable, were larger for MEP amplitude (304.7-585.4 µV) compared to those for cortical silent period duration (25.3-40.8 milliseconds) and MEP latency (1.1-2.1 milliseconds). CONCLUSION The present study demonstrated a feasible method for using TMS to measure CE of the gluteus maximus. Small minimal detectable change values for the cortical silent period and MEP latency provide a reference for future studies.
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142
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Buharin VE, Butler AJ, Rajendra JK, Shinohara M. Enhanced corticospinal excitability with physiologically heightened sympathetic nerve activity. J Appl Physiol (1985) 2013; 114:429-35. [DOI: 10.1152/japplphysiol.01586.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Corticospinal excitability is modulated differently with norepinephrine and dopamine agonists, although both monoamines are released with heightened sympathetic nerve activity. The purpose of this study was to investigate the influence of physiological heightening of sympathetic nerve activity on corticospinal excitability in healthy humans. Subjects were divided into control and experimental groups. In each participant, motor-evoked potentials (MEPs) were measured from the resting first dorsal interosseous muscle of the right hand with transcranial magnetic stimulation (TMS) in two trials separated by 1 h. In the experimental group, sympathetic nerve activity was physiologically heightened during the second trial by applying lower body negative pressure (LBNP). In the control group, sympathetic nerve activity was not altered between the two trials. MEP peak-to-peak amplitude increased from trial 1 to trial 2 in the experimental group only. This increase was evident at a TMS intensity of 130% resting motor threshold and higher. It was concluded that physiological heightening of sympathetic nerve activity with LBNP enhances corticospinal excitability.
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Affiliation(s)
- Vasiliy E. Buharin
- School of Applied Physiology, The Georgia Institute of Technology, Atlanta, Georgia
| | - Andrew J. Butler
- School of Applied Physiology, The Georgia Institute of Technology, Atlanta, Georgia
- Department of Physical Therapy, Georgia State University, Atlanta, Georgia
- Rehabilitation R&D Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia
- Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia
| | - Justin K. Rajendra
- Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia
| | - Minoru Shinohara
- School of Applied Physiology, The Georgia Institute of Technology, Atlanta, Georgia
- Rehabilitation R&D Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia
- Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia
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143
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Poh E, Riek S, Carroll TJ. Ipsilateral corticospinal responses to ballistic training are similar for various intensities and timings of TMS. Acta Physiol (Oxf) 2013; 207:385-96. [PMID: 23082845 DOI: 10.1111/apha.12032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 04/06/2012] [Accepted: 10/15/2012] [Indexed: 12/01/2022]
Abstract
AIM In previous studies, unilateral ballistic training either increased or decreased corticospinal excitability for the untrained opposite limb. The objective here was to investigate whether these discrepancies can be explained by methodological differences such as the intensity of stimulation assessing excitability or the timing of excitability testing after training. METHODS Motor evoked potentials (MEP) were elicited by stimulating the ipsilateral cortex at high intensity (70% MEPmax) and low intensity (20% MEPmax) at specific time-points after performance of 300 ballistic movements of the index finger. RESULTS Ballistic practice significantly facilitated MEP size for high-intensity stimuli, whereas responses to low-intensity stimulation were variable. MEP sizes at individual time-points were not significantly facilitated until 4 min after training, although there was no difference between early and late responses when grouped over multiple time-points. CONCLUSIONS The data indicate that previous discrepancies in ipsilateral responses to ballistic training cannot be attributed to specific procedures used to assess corticospinal excitability as there was no tendency towards depression of MEP amplitude at any point post-exercise for both testing intensities. This suggests that other experimental factors such as locus of attention or availability of visual feedback are more likely to account for the discrepancies.
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Affiliation(s)
- E. Poh
- Centre for Sensorimotor Neuroscience, School of Human Movement Studies; The University of Queensland; Brisbane; Qld; Australia
| | - S. Riek
- Centre for Sensorimotor Neuroscience, School of Human Movement Studies; The University of Queensland; Brisbane; Qld; Australia
| | - T. J. Carroll
- Centre for Sensorimotor Neuroscience, School of Human Movement Studies; The University of Queensland; Brisbane; Qld; Australia
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144
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Gruet M, Temesi J, Rupp T, Levy P, Millet G, Verges S. Stimulation of the motor cortex and corticospinal tract to assess human muscle fatigue. Neuroscience 2013; 231:384-99. [DOI: 10.1016/j.neuroscience.2012.10.058] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/10/2012] [Accepted: 10/29/2012] [Indexed: 10/27/2022]
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145
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Does second-scale intertrial interval affect motor evoked potentials induced by single-pulse transcranial magnetic stimulation? Brain Stimul 2012; 5:526-32. [DOI: 10.1016/j.brs.2011.07.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 11/17/2022] Open
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146
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Kumpulainen S, Mrachacz-Kersting N, Peltonen J, Voigt M, Avela J. The optimal interstimulus interval and repeatability of paired associative stimulation when the soleus muscle is targeted. Exp Brain Res 2012; 221:241-9. [PMID: 22836519 DOI: 10.1007/s00221-012-3165-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/21/2012] [Indexed: 12/13/2022]
Abstract
Changes in the excitability of the cortical projections to muscles in the upper and lower limbs can be induced in the intact human by paired associative stimulation (PAS). An interstimulus interval (ISI) of 25 ms between peripheral nerve and transcranial magnetic stimuli has been found to be effective when targeting hand muscles. The optimal ISI to induce plasticity changes in the cortical projections to lower limbs is still not well established. The purpose of this study was twofold: first, to investigate the effect of PAS with four different ISIs based on the individual latency of the sensory evoked potential (SEP plus 6, 12, 18 and 24 ms) and second, to evaluate the repeatability of the established optimal ISI. Transcranial magnetic stimulation was used to measure changes in the motor evoked potentials (MEPs) of the soleus (SOL) muscle before and after the PAS interventions. Significant increases in the amplitude of SOL MEPs (88 %) were attained with an ISI of SEP latency plus 18 ms (P32 + 18 ms). The PAS effect was long-lasting, input-specific and supraspinal in origin. The intraclass correlation coefficient to test the repeatability of the PAS intervention with the optimal ISI was 0.85. The results show that the excitability of cortical projections to the soleus muscle can be repeatedly increased after PAS with an optimal ISI of SEP plus 18 ms.
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Affiliation(s)
- Susanne Kumpulainen
- Department of Health Science and Technology, Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajersvej 7 D 3, 9220 Aalborg, Denmark.
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Fleming MK, Sorinola IO, Newham DJ, Roberts-Lewis SF, Bergmann JHM. The effect of coil type and navigation on the reliability of transcranial magnetic stimulation. IEEE Trans Neural Syst Rehabil Eng 2012; 20:617-25. [PMID: 22695363 DOI: 10.1109/tnsre.2012.2202692] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The objective of this study was to investigate reliability of transcranial magnetic stimulation (TMS) parameters for three coil systems; hand-held circular and figure-of-eight and navigated figure-of-eight coils. Stimulus response curves, intracortical inhibition (SICI) and facilitation (ICF) were studied in the right first dorsal interosseus muscle of 10 healthy adults. Each coil system was tested twice per subject. Navigation was conducted by a custom built system. Cortical excitability showed moderate-to-good reliability for the hand-held and navigated figure-of-eight coils (Intraclass correlation coefficients (ICCs) 0.55-0.89). The circular coil showed poor reliability for motor evoked potential (MEP) amplitude at 120% resting motor threshold (RMT; MEP(120)) and MEP sum (ICCs 0.09 & 0.48). Reliability for SICI was good for all coil systems when an outlier was removed (ICCs 0.87-0.93), but poor for ICF (ICCs < 0.3). The circular coil had a higher MEP(120) than the navigated figure-of-eight coil (p = 0.004). Figure-of-eight coils can be used confidently to investigate cortical excitability over time. ICF should be interpreted with caution. The navigation device frees the experimenter and enables tracking of the position of the coil and subject. The results help guide the choice of coil system for longitudinal measurements of motor cortex function.
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Affiliation(s)
- Melanie K Fleming
- Centre of Human and Aerospace Physiological Sciences, School of Biomedical Sciences, King's College London, United Kingdom.
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148
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Brain motor excitability and visuomotor coordination in 8-year-old children born very preterm. Clin Neurophysiol 2012; 123:1191-9. [DOI: 10.1016/j.clinph.2011.09.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 09/09/2011] [Accepted: 09/21/2011] [Indexed: 11/18/2022]
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149
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Cortes M, Black-Schaffer RM, Edwards DJ. Transcranial magnetic stimulation as an investigative tool for motor dysfunction and recovery in stroke: an overview for neurorehabilitation clinicians. Neuromodulation 2012; 15:316-25. [PMID: 22624621 DOI: 10.1111/j.1525-1403.2012.00459.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
RATIONALE An improved understanding of motor dysfunction and recovery after stroke has important clinical implications that may lead to the design of more effective rehabilitation strategies for patients with hemiparesis. SCOPE Transcranial magnetic stimulation (TMS) is a safe and painless tool that has been used in conjunction with other existing diagnostic tools to investigate motor pathophysiology in stroke patients. Since TMS emerged more than two decades ago, its application in clinical and basic neuroscience has expanded worldwide. TMS can quantify the corticomotor excitability properties of clinically affected and unaffected muscles and can probe local cortical networks as well as remote but functionally related areas. This provides novel insight into the physiology of neural circuits underlying motor dysfunction and brain reorganization during the motor recovery process. This important tool needs to be used with caution by clinical investigators, its limitations need to be understood, and the results should to be interpreted along with clinical evaluation in this patient population. SUMMARY In this review, we provide an overview of the rationale, implementation, and limitations of TMS to study stroke motor physiology. This knowledge may be useful to guide future rehabilitation treatments by assessing and promoting functional plasticity.
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Affiliation(s)
- Mar Cortes
- Department of Neurology & Neuroscience, Winifred Masterson Burke Medical Research Institute, White Plains, NY, USA
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150
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Tallent J, Goodall S, Hortobágyi T, St Clair Gibson A, French DN, Howatson G. Repeatability of corticospinal and spinal measures during lengthening and shortening contractions in the human tibialis anterior muscle. PLoS One 2012; 7:e35930. [PMID: 22563418 PMCID: PMC3338551 DOI: 10.1371/journal.pone.0035930] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 03/27/2012] [Indexed: 01/01/2023] Open
Abstract
Elements of the human central nervous system (CNS) constantly oscillate. In addition, there are also methodological factors and changes in muscle mechanics during dynamic muscle contractions that threaten the stability and consistency of transcranial magnetic stimulation (TMS) and perpherial nerve stimulation (PNS) measures.
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Affiliation(s)
- Jamie Tallent
- School of Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Stuart Goodall
- School of Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Tibor Hortobágyi
- University Medical Center of Groningen, University of Groningen, Groningen, The Netherlands
| | - Alan St Clair Gibson
- School of Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Duncan N. French
- School of Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Glyn Howatson
- School of Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
- Centre for Aquatic Research, University of Johannesburg, Gauteng, South Africa
- * E-mail:
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