The effect of visual scene on VEMP responses

To determine how visual motion direction and the engagement of central versus peripheral visual fields modulate cervical vestibular evoked myogenic potentials (cVEMP). We investigated whether optokinetic stimulation and smooth pursuit, delivered centrally or peripherally, alter cVEMP latency and amplitude. Forty-five healthy adults completed cVEMP testing across seven visual conditions: baseline (fixed gaze) and various optokinetic stimulation directions and smooth pursuit tasks. These stimuli were delivered using either a light bar (central vision, n=13) or an expanded visual surround (peripheral vision, n=32). Primary outcomes were P13 and N23 latencies and peak-to-peak amplitudes, with within-subject comparisons assessing deviations from baseline. Central visual stimulation via the light bar produced no significant changes in cVEMP latencies or amplitudes relative to baseline (p > 0.008). In contrast, peripheral stimulation yielded significant latency prolongations, most prominently for N23 during vertical and horizontal optokinetic motion. P13 effects were less pronounced and inconsistent. Amplitudes did not show systematic changes across any condition. The divergent behaviour of P13 and N23 indicates differential susceptibility of early versus later cVEMP components to visual and cognitive influences. Peripheral visual motion exerts a more substantial influence on vestibulo-collic pathways than central foveal input, primarily by delaying cVEMP latencies without enhancing amplitudes. This pattern contrasts with prior vection-linked reports of latency reductions and amplitude increases, suggesting distinct neural processing for vection versus purely visual motion cues. These findings highlight the potential to leverage peripheral motion to modulate otolith reflex timing in vestibular rehabilitation, warranting confirmation in patient cohorts and with explicit vection quantification