Evaluation of the influence of the finger touch or occlusion stimuli on the vestibulo-ocular reflex

Abstract

　To evaluate the influence of somatosensory input on the vestibulo-ocular reflex (VOR), we assessed young, healthy volunteers with sinusoidal rotation tests. For the control condition, subjects, with their eyes open, were sinusoidally rotated in complete darkness at a frequency of 0.2, 0.4 and 0.8 Hz, with a maximum angular velocity of 60°/s for 30 seconds. Sinusoidal tests were performed at earth vertical axis rotation (EVAR) and 30° nose-up, off-vertical axis rotation (OVAR). In addition to these controls, we implemented two different somatosensory stimulation conditions during the rotation tests, as follows: (1) touch condition: the subjects (n=26) were told to touch the handle with their right index fingers; (2) bite condition: the subjects (n=24) were told to perform maximum voluntary tooth clenching. The change in the VOR gain did not differ significantly across any of the conditions, including EVAR or OVAR under both stimulation 2 conditions. In our previous study, we proposed that arthrokinetic input (i.e., arm movement) had an additive effect on the VOR, but in the present study, light-touch input had no influence on the VOR.