Cortical excitability and interhemispheric connectivity in early relapsing–remitting multiple sclerosis studied with TMS-EEG

  • Evoked potentials (EPs) are well established in clinical practice for diagnosis and prognosis in multiple sclerosis (MS). However, their value is limited to the assessment of their respective functional systems. Here, we used transcranial magnetic stimulation (TMS) coupled with electroencephalography (TMS-EEG) to investigate cortical excitability and spatiotemporal dynamics of TMS-evoked neural activity in MS patients. Thirteen patients with early relapsing–remitting MS (RRMS) with a median Expanded Disability Status Scale (EDSS) of 1.0 (range 0–2.5) and 16 age- and gender-matched healthy controls received single-pulse TMS of left and right primary motor cortex (L-M1 and R-M1), respectively. Resting motor threshold for L-M1 and R-M1 was increased in MS patients. Latencies and amplitudes of N45, P70, N100, P180, and N280 TMS-evoked EEG potentials (TEPs) were not different between groups, except a significantly increased amplitude of the N280 TEP in the MS group, both for L-M1 and R-M1 stimulation. Interhemispheric signal propagation (ISP), estimated from the area under the curve of TEPs in the non-stimulated vs. stimulated M1, also did not differ between groups. In summary, findings show that ISP and TEPs were preserved in early-stage RRMS, except for an exaggerated N280 amplitude. Our findings indicate that TMS-EEG is feasible in testing excitability and connectivity in cortical neural networks in MS patients, complementary to conventional EPs. However, relevance and pathophysiological correlates of the enhanced N280 will need further study.

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Author:Carl Moritz Zipser, Isabella Premoli, Paolo Belardinelli, Nazareth Castellanos, Davide Rivolta, Tonio Heidegger, Florian Müller-Dahlhaus, Ulf Ziemann
Pubmed Id:
Parent Title (English):Frontiers in neuroscience
Publisher:Frontiers Research Foundation
Place of publication:Lausanne
Contributor(s):Domenica Veniero
Document Type:Article
Year of Completion:2018
Date of first Publication:2018/06/08
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2018/07/05
Tag:TMS-EEG; connectivity; excitability; multiple sclerosis; relapsing–remitting; transcranial magnetic stimulation
Issue:Art. 393
Page Number:9
First Page:1
Last Page:9
Copyright © 2018 Zipser, Premoli, Belardinelli, Castellanos, Rivolta, Heidegger, Müller-Dahlhaus and Ziemann. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Institutes:Medizin / Medizin
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0