Repeatability of sound evoked triceps myogenic potentials

Objective: To investigate the repeatability of sound-evoked vestibular evoked myogenic potentials recorded from the triceps (tVEMPs) with and without visual feedback. Design: tVEMP responses to 95 dB nHL 500-Hz tone bursts were recorded in a longitudinal, repeated measures study where P1 and N1 latencies and amplitudes were measured on three separate occasions from the same individuals. Analysis of variance, intra-class correlations, and limits of repeatability analyses were used to assess tVEMP repeatability and effects of visual feedback. Study sample: Fifteen participants (nine women) aged between 18 and 41 years took part. Results: Response rates of 63% and 68% were obtained for tVEMPs with eyes open and closed, respectively. When present, tVEMP latencies and amplitudes exhibited fair to good repeatability. Repeatability of tVEMP latencies and amplitudes measured using Bland-Altman methods was poorer with eyes closed. Conclusions: Sound-evoked tVEMP response rates are too low to support their clinical utility at the moment. tVEMP response rate may be improved by refining the balance task to include a force related target. Better tVEMP repeatability with eyes open supports the hypothesis that the response is modulated by visual feedback, and is consistent with studies reporting triceps responses to galvanic stimulation.