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The effect of pulse shape in theta-burst stimulation: Monophasic vs biphasic TMS

Authors :
Karen Wendt
Majid Memarian Sorkhabi
Charlotte J. Stagg
Melanie K. Fleming
Timothy Denison
Jacinta O'Shea
Source :
Brain Stimulation, Vol 16, Iss 4, Pp 1178-1185 (2023)
Publication Year :
2023
Publisher :
Elsevier, 2023.

Abstract

Background: Intermittent theta-burst stimulation (i) (TBS) is a transcranial magnetic stimulation (TMS) plasticity protocol. Conventionally, TBS is applied using biphasic pulses due to hardware limitations. However, monophasic pulses are hypothesised to recruit cortical neurons more selectively than biphasic pulses, predicting stronger plasticity effects. Monophasic and biphasic TBS can be generated using a custom-made pulse-width modulation-based TMS device (pTMS). Objective: Using pTMS, we tested the hypothesis that monophasic iTBS would induce a stronger plasticity effect than biphasic, measured as induced increases in motor corticospinal excitability. Methods: In a repeated-measures design, thirty healthy volunteers participated in three separate sessions, where monophasic and biphasic iTBS was applied to the primary motor cortex (M1 condition) or the vertex (control condition). Plasticity was quantified as increases in motor corticospinal excitability after versus before iTBS, by comparing peak-to-peak amplitudes of motor evoked potentials (MEP) measured at baseline and over 60 min after iTBS. Results: Both monophasic and biphasic M1 iTBS led to significant increases in MEP amplitude. As predicted, linear mixed effects (LME) models showed that the iTBS condition had a significant effect on the MEP amplitude (χ2 (1) = 27.615, p

Details

Language :
English
ISSN :
1935861X
Volume :
16
Issue :
4
Database :
Directory of Open Access Journals
Journal :
Brain Stimulation
Publication Type :
Academic Journal
Accession number :
edsdoj.4eb92c5576ff4ce18ec3af54cc52b5be
Document Type :
article
Full Text :
https://doi.org/10.1016/j.brs.2023.08.001