Deep transcranial magnetic stimulation is superior to normal in motor-evoked potentials

Abstract

Background: Deep transcranial magnetic stimulation (dTMS) using an H7 coil is widely applied in the treatment of several neurological diseases. However, whether dTMS with an H7 coil is superior to figure-of-eight coil transcranial magnetic stimulation (TMS) for neurophysiological assessment remains unclear.

Methods: This study compared the latency and amplitude of motor-evoked potentials (MEPs) induced by dTMS with an H7 coil and figure-of-eight coil TMS in the lower-extremity region of the primary motor cortex (M1) in healthy individuals.

Results: dTMS with the H7 coil demonstrated a significantly higher elicitation rate for resting MEPs than figure-of-eight coil TMS, whereas no significant difference was observed for facilitated MEPs. The latency and amplitude of both resting and facilitated MEPs differed significantly between the two stimulation methods. Significant differences in elicitation rate and amplitude were observed between resting and facilitated MEPs, but no latency difference was detected. No significant differences in elicitation rate, latency, or amplitude were observed between the left and right sides for MEPs induced by either stimulation technique.

Conclusions: dTMS with an H7 coil is an effective method for eliciting resting MEPs in the lower extremity but does not outperform figure-of-eight coil TMS for facilitated MEPs. The responsiveness is influenced by facilitation status but not by handedness.