Utricular Dysfunction and Hearing Impairment Affect Spatial Navigation in Community-dwelling Healthy Adults: Analysis from the Baltimore Longitudinal Study of Aging.

INTRODUCTION: Spatial navigation, the ability to move through one's environment, is a complex skill utilized in everyday life. The effects of specific vestibular end-organ deficits and hearing impairments on spatial navigation have received little to no attention. We hypothesized that hearing impairment adversely affects spatial navigation and that bi-modal impairments (vestibular and hearing) further impair navigation ability.

METHODS: Data from 182 participants in the Baltimore Longitudinal Study of Aging who had interpretable results for the video head impulse test (vHIT), cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials, audiometric testing, and the triangle completion test (TCT) were retrospectively analyzed. Multiple linear regression, controlling for age, sex, and cognition, was employed to identify predictors of TCT performance in terms of end-point error, angle deviation, and distance walked.

RESULTS: oVEMP abnormalities were associated with larger end-point error (p=0.008) and larger angle deviation (p=0.002) but were not associated with distance walked (p=0.392). Abnormalities on cVEMP and vHIT were not associated with distance walked (p=0.835, p=0.300), end-point error (p=0.256, p=0.808), or angle deviation (p=0.192, p=0.966). Compared with normal hearing adults, hearing impaired adults walked a shorter distance during the TCT (p=0.049) but had similar end-point error (p=0.302) and angle deviation (p=0.466). There was no interaction between vestibular and hearing function for predicting spatial navigation ability.

CONCLUSION: In this cohort analysis, utricular dysfunction and hearing impairment were associated with poorer spatial navigation performance. We postulate that hearing impairment negatively affects one's ability to use real-time, intrinsic auditory cues and/or prior experience to guide navigation.