Biomarkers Obtained by Transcranial Magnetic Stimulation of the Motor Cortex in Epilepsy
- 1Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, United States
- 2FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, United States
- 3Berenson-Allen Center for Noninvasive Brain Stimulation, United States
Epilepsy is associated with numerous neurodevelopmental disorders. Transcranial magnetic stimulation (TMS) of the motor cortex coupled with electromyography (EMG) enables biomarkers that provide measures of cortical excitation and inhibition that are particularly relevant to epilepsy and related disorders. The motor threshold (MT), cortical silent period (CSP), short interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long interval intracortical inhibition (LICI) are among TMS-derived metrics that are modulated by antiepileptic drugs. TMS may have a practical role in optimization of antiepileptic medication regimens, as studies demonstrate dose-dependent relationships between TMS metrics and acute medication administration. A close association between seizure freedom and normalization of cortical excitability with long-term antiepileptic drug use highlights a plausible utility of TMS in measures of anti-epileptic drug efficacy. Finally, TMS-derived biomarkers distinguish patients with various epilepsies from healthy controls, and thus may enable development of disorder-specific biomarkers and therapies both within and outside of the epilepsy realm.
Keywords: Biomarker (development), transcranial magenetic stimulation (TMS), Epilepsy - Abnormalities, classification, drug therapy, drug development and application, Neuromodulation, Motor cortex excitability
Received: 20 Jul 2019;
Accepted: 23 Sep 2019.
Copyright: © 2019 Tsuboyama, Kaye and Rotenberg. 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(s) 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.
* Correspondence: Dr. Alexander Rotenberg, Department of Neurology, Boston Children's Hospital, Division of Epilepsy and Clinical Neurophysiology, Boston, 02115, Massachusetts, United States, firstname.lastname@example.org