TMS-evoked N100 responses as a prognostic factor in acute stroke

Abstract

SummaryRehabilitation programs, to be efficiently tailored, need clear prognostic markers. In acute stroke, neurophysiological measures, such as motor evoked potentials (MEPs), have been proposed, although with discordant results. The aim of this study was to identify a reliable neurophysiological measure of recovery in acute poststroke individuals by combining MEPs and the N100 component of transcranial magnetic stimulationevoked potentials (TEPs). Nine acute post-stroke subjects were included. Clinical evaluation performed in the first week after the event included administration of the European Stroke Scale and Barthel Index and recording of MEPs and TEPs; administration of the clinical scales was repeated after one and three months. The presence/absence of MEPs and TEPs showed correlations with motor outcome. Individuals with a poorer outcome showed absence of both MEPs and TEPs; absence of MEPs alone was related to a partial recovery. Given the results of this exploratory study, further investigation is needed to define the accuracy of combined use of MEPs and TEPs as an approach for predicting motor recovery after acute stroke.

Evaluation of White Matter Integrity Utilizing the DELPHI (TMS-EEG) System

“…These data support DELPHI (TMS-EEG) as a tool for neurophysiological evaluation of network connectivity and its potential as an affordable, safe and available tool for monitoring and evaluating brain network structural and functional abnormalities in specific neuronal circuits. These results are supported by previous studies ( Manganotti et al, 2015 ; Lanza et al, 2017 ; Hordacre et al, 2019 ) and indicate that in order to get a more comprehensive and localized evaluation of functional and structural brain connectivity, integrity, and plasticity, at least two contralateral stimulation sites are required. Moreover, direct TMS stimulation of frontal, medial, and posterior areas may increase TMS-EEG sensitivity to both structural and functional ROIs.…”

“…Moreover, direct TMS stimulation of frontal, medial, and posterior areas may increase TMS-EEG sensitivity to both structural and functional ROIs. TMS-EEG technology has been shown to provide insight into the evaluation and monitoring of functional effective connectivity in various brain disorders, such as Alzheimer’s disease (AD), stroke, and TBI prognosis and rehabilitation prediction ( Bortoletto et al, 2015 ; Manganotti et al, 2015 ; Tremblay et al, 2019 ). Our study supports the clinical utility of TMS-EEG in brain disorders of functional and structural effective connectivity, displays high sensitivity of DELPHI neurophysiological measures to WM-related structural connectivity changes as measured with DTI, and supports specific fiber localization correlated to the stimulation area.…”

Evidence for interhemispheric imbalance in stroke patients as revealed by combining transcranial magnetic stimulation and electroencephalography

“…On the other hand, as previously observed, cortical activity of both the hemispheres in stroke patients was generally lower compared to HC, likely due to altered excitability in the stimulated neuronal populations and in their cortico-cortical connections (Pellicciari et al, 2018). So far, only a few studies applied TMS-EEG to evaluate the cortical state following a stroke event (Borich, Wheaton, Brodie, Lakhani, & Boyd, 2016;Gray, Wolf, & Borich, 2017;Manganotti, Acler, Masiero, & del Felice, 2015;Pellicciari et al, 2018). However, these studies were mainly focused on the analysis of cortical activity in the AH without an in-depth characterization of the interhemispheric interactions.…”

Diagnostic capabilities of transcranial magnetic stimulation to predict motor recovery after a stroke

“…Возможная роль этих показателей для прогноза и понимания процессов двигательного восстановления после инсульта только начинает исследоваться. Например, для наиболее хорошо охарактеризованного тормозного компонента ТМС-вызванных потенциалов -N100 [40,43] было показано, что его наличие со стороны пораженного полушария даже в случае отсутствия ВМО может говорить о лучшем прогнозе двигательного восстановления [44]. В недавно опубликованном лонгитюдном исследовании у пациентов после инсульта наблюдалось снижение амплитуды всех компонентов ТМС-вызванных потенциалов, а также снижение вызванной осцилляторной активности в альфа-, бета-и дельта-диапазонах [45].…”

“…Уже получены первые интересные ТМС-ЭЭГ-данные об изменениях связности в мозге после инсульта. Ранее уже было описано, что наличие компонента N100 на ТМС-вызванных потенциалах, который является косвенным отражением состояния таламо-кортикальных связей, может быть дополнительным маркером, определяющим лучший прогноз двигательного восстановления [44]. Другой пример -ТМС-ЭЭГ-оценка межполушарного взаимодействия: при использовании парадигмы оценки ипсилатерального периода молчания (т. е. ТМС одиночными стимулами на фоне сокращения мышц руки ипсилатеральной области стимуляции) у пациентов в хроническом периоде ишемического инсульта наблюдалось увеличение когерентности ТМСин дуцированной бета-активности, отражающее изменение эффективной межполушарной связности в момент выполнения движения у пациентов после инсульта.…”