Otolith Deterioration: Factors Affecting Microvascular and Structural Integrity.

BACKGROUND AND PURPOSE: Otoliths degenerate with aging, but the underlying factors are not well understood. We aimed to identify risk factors associated with otolith function in patients with dizziness and vertigo. METHODS: This cross-sectional study analyzed 624 patients with benign paroxysmal positional vertigo, benign recurrent vertigo, or persistent postural-perceptual dizziness who presented at a tertiary referral center between March 2017 and July 2021. Otolith function was assessed using summated amplitudes of cervical and ocular vestibular evoked myogenic potentials (SA-cVEMPs and SA-oVEMPs). The relationships between otolith function and potential risk factors were analyzed using two types of generalized linear model: a zero-adjusted gamma model for SA-cVEMPs and a standard gamma model for SA-oVEMPs. RESULTS: In the multivariable model, SA-cVEMP was negatively associated with age (β=-0.012, effect=-1.23%), female sex (β=-0.110, effect=-10.42%), and free thyroxine (β=-0.298, effect=-25.74%), and positively associated with high-density lipoprotein cholesterol (β=0.005, effect=0.46%). SA-oVEMP was negatively associated with age (β=-0.008, effect=-0.84%) and positively associated with female sex (β=0.141, effect=15.19%). CONCLUSIONS: The findings of this study suggest that various systemic factors beyond age and sex are related to otolith function via effects on the microvasculature and structural constituents. These findings provide new insights into potential mechanisms of otolith degeneration and highlight the impact of systemic factors on otolith function.