Weak magnetic vestibular stimulation decreases postural sway.

ABSTRACT

BACKGROUND: Perceptible galvanic vestibular stimulation (GVS) causes nystagmus and postural sway deterioration. Conversely, imperceptible GVS improves postural stability, suggesting the presence of stochastic resonance. RESEARCH QUESTION Similar to GVS, strong magnetic vestibular stimulation of 7 T induces nystagmus and increases body sway. Thus, a relatively small magnetic stimulation may improve postural stability. In this study, we measured the effect of a relatively small magnetic field on postural sway. METHODS: Posturography was performed in eight healthy participants using a stabilometer with foam rubber on board. The center of pressure (COP) trajectories were recorded in both the anterior-posterior and medial-lateral directions for 60 s with the eye closed. Neodymium magnets (0.4 T) or aluminum disks of similar size (0 T) were placed bilaterally over the mastoid processes. RESULTS: Both the trajectory length and envelopment area of the COP movement with 0.4 T were significantly smaller than those with 0 T. SIGNIFICANCE: The relatively smaller magnetic vestibular stimulation decreased postural sway. This method may be useful for improving the vestibular function and related reflexes.