Vestibular Function is Associated with Prefrontal and Sensorimotor Cortical Gray Matter Volumes in a Cross-Sectional Study of Healthy, Older Adults

Abstract

Background The vestibular system is associated with alterations in the structure and function of the central nervous system. Yet, whether age-related vestibular loss is related to volume loss in the cerebral cortical areas that have been reported to receive vestibular input remains unknown. In this cross-sectional study of 117 healthy, older adults from the Baltimore Longitudinal Study of Aging, we examine the relationships between age-related vestibular functions and the gray matter volumes of the prefrontal cortex and its subregions and of the sensorimotor cortex—regions known to process vestibular information. Methods T1-weighted MRI scans were automatically segmented using MRICloud. Log-linear multiple regression was used to investigate the relationships between average regional volume and vestibular function, adjusting for age, sex, and intracranial volume. Permutation testing was used for hypothesis testing, and bootstrapping was used to estimate confidence intervals. Results We found that age-related changes in vestibular end-organ function are associated with differentially altered gray matter volumes in the prefrontal and sensorimotor cortices, with many findings persisting when considering left (or right) side only. Concomitant with age-related, global brain atrophy, lower canal and utricular function were associated with additional volume atrophy of the prefrontal cortex and middle frontal gyrus, respectively. Lower saccular and utricular function were associated with the preservation of the volumes of the sensorimotor cortex and the pole of the superior frontal gyrus, respectively, against age-related, global brain atrophy. Canal and utricular function were not associated with the volumes of the sensorimotor cortex, and saccular function was not associated with the relative volumes of the prefrontal cortex. Conclusion Together, these findings of relative volume preservation or additional atrophy suggest that vestibular function may play a role in the resilience to or magnification of global age effects on cerebral cortical structure.