A Pilot Study To Investigate The Effects Of Imperceptible Wrist Vibration On The Corticospinal Motor Excitability Of Healthy Adults

The study investigated changes in corticomotor excitability of healthy adults with imperceptible white-noise vibration applied to the wrist. Previous studies have shown that the application of unperceivable white-noise vibration to the wrist induced improvements in sensory and motor function of the hand, not only in stroke survivors but also in healthy adults (Seo et al., 2014; Hur et al., 2014; Enders et al., 2013; Lakshminarayanan et al., 2015). Despite the potential that this vibration protocol me be adopted for therapy and in daily living activities to result in clinical benefits of stroke survivors and others with sensorimotor issues, knowledge about the way this vibration affects the neurophysiology, specifically the sensorimotor excitability, is not well understood. The purpose of this study was to investigate the neurophysiological effects of the imperceptible white-noise vibration on corticospinal motor excitability of the hand. Motor excitability was assessed using Transcranial Magnetic Stimulation (TMS), and by measuring the cortical silent period, intracortical inhibition and facilitation, and slope of the recruitment curve of the primary motor cortex for a hand muscle. These measures were compared between the vibration on and off conditions which were tested in a random order. Twelve healthy adults were tested. The results showed that the vibration resulted in marginally less intracortical inhibition when compared to the off condition (p < 0.04). Other corticomotor excitability measures were not affected by the vibration (p >0.29). Taken together with previous studies, imperceptible white-noise vibration may improve hand function by enhancing sensation and not directly the motor excitability of the hand, although more Subjects need to be tested for intracortical inhibition. This study contributes to elucidating neural mechanisms of the vibration-based sensory stimulation approach.<p></p>