Investigating the effects of subsensory stimulation with a small peripheral magnetic stimulation device on corticospinal excitability: a pilot clinical study

Abstract

We have developed a small magnetic stimulator employing a rotating permanent field, called a spinning permanent magnet (SPM). The SPM device is designed for peripheral wear on the arm or leg and delivers subsensory stimulation (below the threshold of conscious perception). Established research demonstrates that peripheral magnetic stimulation above the motor threshold can modulate corticospinal excitability through ascending inputs. However, the effects of subsensory threshold peripheral magnetic stimulation remain unclear. In this study, we investigate the modulatory impact of SPM stimulation on the extensor carpi radialis (ECR) muscle of the right forearm in 10 healthy adults. Participants received two conditions: real stimulation with the SPM device and sham stimulation emulating the device’s application. Motor-evoked potentials, indicative of corticospinal excitability, were recorded in the right ECR following stimulation. Although no significant differences were observed between the two conditions and before and after stimulation, the small sample size in this study makes it difficult to draw definitive conclusions. Further research is needed. While low-intensity magnetic stimulation and static magnetic fields have shown promise in pain management, blood circulation, and autonomic nervous system modulation, further research should explore the effects of SPM on anatomical structures beyond central neuromodulation.