Effects of Repetitive Peripheral Magnetic Stimulation through Hand Splint Materials on Induced Movement and Corticospinal Excitability in Healthy Participants.

Akihiko Asao,Tomonori Nomura,Kenichi Shibuya

doi:10.3390/brainsci12020280

Akihiko Asao, Tomonori Nomura + Show 1 more

Open Access

https://doi.org/10.3390/brainsci12020280

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Journal: Brain sciences	Publication Date: Feb 17, 2022
Citations: 3	License type: CC BY 4.0

Affiliation: Niigata University of Health and Welfare

Abstract

Repetitive peripheral magnetic stimulation (rPMS) is a non-invasive neuromodulation technique. Magnetic fields induced by rPMS pass through almost all materials, and it has clinical applications for neurorehabilitation. However, the effects of rPMS through clothing and orthosis on induced movement and corticospinal excitability remain unclear. The aim of this study was to determine whether rPMS induces movement and enhances corticospinal excitability through hand splint materials. rPMS was applied directly to the skin (L0) and through one (L1) or two (L2) layers of splint material in 14 healthy participants at 25-Hz, 2-s train per 6 s for a total of 20 min. rPMS was delivered to the forearm with the stimulus intensity set to 1.5-times the train intensity-induced muscle contractions under the L0 condition. We recorded induced wrist movements during rPMS and motor-evoked potentials of the extensor carpi radialis pre- and post-application. The results showed that rPMS induced wrist movements in L0 and L1, and it facilitated corticospinal excitability in L0 but not in L1 and L2. This suggests that rPMS can make electromagnetic induction on periphery even when applied over clothing and orthosis and demonstrates the potential clinical applications of this technique for neurorehabilitation.

Highlights

Peripheral magnetic stimulation (PMS) is a technique that induces eddy currents, which penetrate the peripheral nerves and muscle spindles, using a time-varying pulsed magnetic field via a coil on the upper and lower extremities as well as the trunk
We investigated the effects of Repetitive PMS (rPMS) applied over hand splint materials on induced movement and corticospinal excitability in healthy participants
Our results show that rPMS induced wrist movement when the stimulus coil was placed on the skin and when applied over one layer of hand splint material

Summary

Introduction

Peripheral magnetic stimulation (PMS) is a technique that induces eddy currents, which penetrate the peripheral nerves and muscle spindles, using a time-varying pulsed magnetic field via a coil on the upper and lower extremities as well as the trunk. Repetitive PMS (rPMS) is a novel neuromodulation technique that induces activation of mechanoreceptors of group Ia, Ib, and II nerve fibers during rhythmic contraction and relaxation, similar to muscle vibration [1]. It induces activation of the sensorimotor cortex and the front-parietal network, including premotor and parietal areas [1,2]. RPMS is painless, non-invasive, easy to administer, and penetrates deeper [13]. These are great advantages for the clinical application of neurorehabilitation. While it is theoretically clear that rPMS stimulates muscle spindles and peripheral nerves through clothing or orthosis, this has not yet been investigated experimentally

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