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Date of Graduation
Doctor of Audiology (AuD)
Department of Communication Sciences and Disorders
Both the vestibular system and optokinetic system generate conjugate eye movements in response to either movement of the head or movement of the visual surround. Both systems help to maintain gaze stability. While the VOR is most sensitive to input frequencies above .2 Hz, the optokinetic system helps maintain gaze stability at lower frequencies. Previous research on perceptual thresholds across the two sensory modalities shows that there are frequency-dependent differences between vestibular and visual perception. The purpose of this study is to extend previous vestibular psychophysics work by 1) comparing magnitude estimates from vestibular stimulation to visual stimulation across multiple frequencies, and 2) assess the feasibility of using virtual reality to provide an optokinetic stimulus equal to that of the rotary chair at frequencies where both systems are sensitive.
Participants were exposed to 12 experimental conditions of angular rotation of varying frequencies and peak velocities across both sensory modalities. Vestibular stimulation was provided with a rotary chair and equivalent visual stimulation was provided with a virtual reality headset. Participants provided magnitude estimates of their speed and spatial orientation using a visual analog scale. Results reveal that speed magnitude estimates increased with peak velocity and frequency for both modalities. Spatial orientation magnitude estimates decreased with increasing frequency and increased with increasing peak velocity. Spatial orientation was underestimated under visual stimulation. Based on these results, it was concluded that at frequencies from 0.08 to 0.32 Hz, both vestibular and visual modalities provide adequate cues for motion sensitivity and virtual reality can be used as an OKN stimulus to assess motion perception (specifically speed/intensity).
Hernon, Erin, "Magnitude estimates of angular motion: Perception of speed and spatial orientation across visual and vestibular modalities" (2023). Dissertations, 2020-current. 117.