Sexual Dimorphism in VEMP peak to trough Latency

The cervical vestibular-evoked myogenic potential (VEMP) was assessed in 24 women and 24 men having a mean age of 19.5 years (SD 0.7). Whilst there was no group difference in VEMP peak to trough (p1-n1) amplitude, VEMP p1-n1 latency was found to be shorter for women than for men by 2.4 ms (95% CI [-0.9, -3.9], chi squared (1) 9.6, p = 0.0020). This equates to 21% of the mean 11.4 ms VEMP p1-n1 latency across women and men. It is a reversal of findings in several prior studies, which are reviewed here. Statistical modelling based on the current study suggests some prior studies were underpowered to detect a sex difference in VEMP latency. Possible causes for sex difference in VEMPs are discussed. Candidate explanations include head resonance, superposition of motor unit action potentials and influence of sex hormones. These explanations are not mutually exclusive, and multiple factors may contribute to difference in VEMP measurement between women and men. This study used a methodology developed in Gattie et al. (2021), which addresses sound exposure concerns with the high amplitude air conducted stimuli necessary to evoke a VEMP response. It is suggested that body conducted stimuli may be preferable for VEMP testing in which ear-specific information is not required.