Relationship between rTMS effects and MEP features before rTMS

Kazuhisa Nojima; Keiji Iramina

doi:10.1016/j.neulet.2017.11.030

Relationship between rTMS effects and MEP features before rTMS

Neurosci Lett. 2018 Jan 18:664:110-115. doi: 10.1016/j.neulet.2017.11.030. Epub 2017 Nov 12.

Authors

Kazuhisa Nojima¹, Keiji Iramina²

Affiliations

¹ Graduate School of Systems Life Sciences, Kyushu University, 1-1-3 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: nojima-kazuhisa@ab.auone-net.jp.
² Graduate School of Systems Life Sciences, Kyushu University, 1-1-3 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Department of Informatics, Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan. Electronic address: iramina@inf.kyushu-u.ac.jp.

PMID: 29141190
DOI: 10.1016/j.neulet.2017.11.030

Abstract

Repetitive transcranial magnetic stimulation (rTMS) is a promising method for use in the clinical field, as it can induce modulation of cortical excitability. Generally, rTMS inhibits the motor cortex when delivered at less than 1 Hz. However, it has been indicated that a facilitative effect is induced by 1 Hz rTMS, depending on the stimulation parameters and the individual. Therefore, the aim of this study was to investigate the features of the subject that could affect the 1 Hz rTMS effect when rTMS stimulus conditions change. First, motor evoked potentials (MEP) were measured under rTMS conditions with a variety of stimulus intensities and numbers of pulses. The MEP features before rTMS and the MEP modulation by the rTMS were then analyzed. Furthermore, correlations between the MEP features and the rTMS effect were investigated. It was found that the MEP amplitude and MEP onset before rTMS can influence the rTMS effect. Furthermore, negative correlations were found between these MEP features and the rTMS effect. MEPs with a small amplitude and early latency were little influenced by the inhibitive effect of 1 Hz rTMS, while MEPs with a large amplitude and late latency were readily affected by the inhibitive effect of 1 Hz rTMS. In this study, we focused on the MEP features before rTMS and identified the features of the subject that could influence the rTMS effect when the rTMS stimulus condition was changed.

Keywords: Cortical excitability; Motor evoked potentials; Repetitive transcranial magnetic stimulation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cortical Excitability / physiology
Evoked Potentials, Motor / physiology*
Female
Humans
Male
Motor Cortex / physiology*
Transcranial Magnetic Stimulation / methods*
Young Adult