The Relationship Between the Vestibular Ocular Reflex and Perception in Young and Healthy Adults

Vestibular impairments are often identified through measures of vestibular reflexes such as the vestibulo-ocular reflex (VOR). However, in clinical practice measures of the VOR do not always correlate with the patient’s reported symptoms. In contrast to physiologic measures like the VOR, psychophysical methods can be used to assess a person’s perception of movement. Previous psychophysics research shows that perceptual thresholds of angular motion do not correlate with VOR measures, but this has not been assessed at suprathreshold levels. The purpose of this study was to assess whether vestibular reflexive responses (i.e., VOR) were correlated to the patient’s perception of movement at suprathreshold levels of angular motion in the rotary chair. We evaluated 35 young healthy adults using sinusoidal harmonic acceleration with a rotary chair under 12 different stimulus conditions that varied by frequency and peak velocity at levels well above perceptual threshold. Participants provided magnitude estimates of speed using a visual analog scale. Maximum slow phase velocity (mSPV) of the eyes was used as a measure of the VOR as well as the more frequently used clinical measure of VOR gain (ratio of mSPV to velocity of the chair). Both measures of physiology were recorded simultaneously with the magnitude estimates. Results showed a statically significant correlation (r = 0.582) between magnitude estimates of speed and mSPV and no significant correlation between magnitude estimates and VOR gain. Overall, perception of suprathreshold vestibular stimuli does not correlate with the clinically used variable of VOR gain, but it does correlate with the mSPV in young, healthy participants