Modulation of the Corticomotor Excitability by Repetitive Peripheral Magnetic Stimulation on the Median Nerve in Healthy Subjects

Abstract

Objective: We aimed to examine the effects of repetitive peripheral nerve magnetic stimulation (rPNMS) on the excitability of the contralateral motor cortex and motor function of the upper limb in healthy subjects.Methods: Forty-six healthy subjects were randomly assigned to either a repetitive peripheral nerve magnetic stimulation group (n = 23) or a sham group (n = 23). The repetitive peripheral nerve magnetic stimulation group received stimulation using magnetic pulses at 20 Hz, which were applied on the median nerve of the non-dominant hand, whereas the sham group underwent the same protocol without the stimulation output. The primary outcome was contralateral transcranial magnetic stimulation (TMS)-induced corticomotor excitability for the abductor pollicis brevis of the stimulated hand in terms of resting motor threshold (rMT), the slope of recruitment curve, and peak amplitude of motor evoked potential (MEP), which were measured at baseline and immediately after each session. The secondary outcomes were motor hand function including dexterity and grip strength of the non-dominant hand assessed at baseline, immediately after stimulation, and 24 h post-stimulation.Results: Compared with the sham stimulation, repetitive peripheral nerve magnetic stimulation increased the peak motor evoked potential amplitude immediately after the intervention. The repetitive peripheral nerve magnetic stimulation also increased the slope of the recruitment curve immediately after intervention and enhanced hand dexterity after 24 h. However, the between-group difference for the changes was not significant. The significant changes in hand dexterity and peak amplitude of motor evoked potential after repetitive peripheral nerve magnetic stimulation were associated with their baseline value.Conclusions: Repetitive peripheral nerve magnetic stimulation may modulate the corticomotor excitability together with a possible lasting improvement in hand dexterity, indicating that it might be helpful for clinical rehabilitation.

Implicit Body Representation of the Hand Enlarged by Repetitive Peripheral Magnetic Stimulation within the Boundary of a Real Hand

“…Nito et al also demonstrated that a significant increase in MEP was observed up to 60 min following 15 min of 50 or 25 Hz rPMS [41]. Jia, Y et al found that single-session 20 Hz rPMS could modulate corticomotor excitability by measuring MEP, together with a possible lasting improvement in hand dexterity [42]. We observed a 20 min lasting effect of single-session 50 Hz rPMS on implicit body representation of the hand, which is in accordance with the above research.…”

Effects of repetitive peripheral magnetic stimulation on spasticity evaluated with modified Ashworth scale/Ashworth scale in patients with spastic paralysis: A systematic review and meta-analysis

“…Previous studies have demonstrated that rPMS with single or multiple sessions can significantly reduce spasticity and increase upper limb motor function in patients following central nervous system (CNS) lesions ( 8 – 10 ). The underlying mechanism might be related to the neuromodulation effect when rPMS is placed over muscle or nerves of the paretic limb ( 9 , 11 – 13 ).…”

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

“…It also induces activation of not only the sensorimotor cortex but also the front-parietal network, including premotor and parietal areas [ 1 , 2 ]. In addition, rPMS modulates the corticospinal excitability and intracortical circuits as well as enhances motor performance in healthy individuals [ 3 , 4 , 5 ]. Moreover, rPMS is a novel neurorehabilitation method for improving sensorimotor dysfunctions in stroke [ 1 , 6 , 7 , 8 , 9 , 10 ] and reducing lower back pain [ 11 , 12 ].…”