OBJECTIVE: To assess the effects of vertical and horizontal gaze, head rotation, body position, and vision on the ocular vestibular evoked myogenic potential (OVEMP) produced by air-conducted (AC) sound. METHODS: Ten normal subjects were stimulated by 500 Hz 2 ms AC tone bursts at 136-142 dB peak SPL. OVEMPs were recorded from electrodes placed beneath the eyes. Angles of vertical gaze ranged from maximal downward to upward gaze in increments of 5-10 degrees . Horizontal gaze was measured during elevation and ranged from 20 degrees adduction to 20 degrees abduction. RESULTS: Increasing vertical gaze increased OVEMP amplitude, especially for the contralateral eye (neutral vs maximal upward gaze; contra: 1.0 vs 2.6 microV; ipsi: 0.8 vs 0.9 microV; P<0.001). OVEMPs from the contralateral eye peaked significantly earlier in the upward gaze positions (contra: 9.2 ms; ipsi: 10.4 ms; P<0.001), but peaked later during downward gaze (contra: 14.2 ms; ipsi: 11.4 ms; P=0.014). There were small effects of horizontal gaze and supine body position, but no effects of head rotation or vision. CONCLUSIONS: OVEMP amplitudes are strongly modulated by gaze position. Truncal position also affects OVEMP amplitude. SIGNIFICANCE: This study quantifies the effect of gaze on the OVEMP and demonstrates the importance of controlling for gaze in clinical and experimental studies.
OBJECTIVE: To assess the effects of vertical and horizontal gaze, head rotation, body position, and vision on the ocular vestibular evoked myogenic potential (OVEMP) produced by air-conducted (AC) sound. METHODS: Ten normal subjects were stimulated by 500 Hz 2 ms AC tone bursts at 136-142 dB peak SPL. OVEMPs were recorded from electrodes placed beneath the eyes. Angles of vertical gaze ranged from maximal downward to upward gaze in increments of 5-10 degrees . Horizontal gaze was measured during elevation and ranged from 20 degrees adduction to 20 degrees abduction. RESULTS: Increasing vertical gaze increased OVEMP amplitude, especially for the contralateral eye (neutral vs maximal upward gaze; contra: 1.0 vs 2.6 microV; ipsi: 0.8 vs 0.9 microV; P<0.001). OVEMPs from the contralateral eye peaked significantly earlier in the upward gaze positions (contra: 9.2 ms; ipsi: 10.4 ms; P<0.001), but peaked later during downward gaze (contra: 14.2 ms; ipsi: 11.4 ms; P=0.014). There were small effects of horizontal gaze and supine body position, but no effects of head rotation or vision. CONCLUSIONS: OVEMP amplitudes are strongly modulated by gaze position. Truncal position also affects OVEMP amplitude. SIGNIFICANCE: This study quantifies the effect of gaze on the OVEMP and demonstrates the importance of controlling for gaze in clinical and experimental studies.
Authors: László T Tamás; Americo A Migliaccio; Christopher J Todd; Michael C Schubert; Béla Büki Journal: Exp Brain Res Date: 2021-03-02 Impact factor: 1.972