Hearing and Mobility in Aging-The Moderating Role of Neuropsychological Function.

Abstract

In older persons, neuropsychological function, especially sensorimotor function, is strongly associated with mobility. Hearing impairment is related to poor mobility, and we hypothesize that such relationships would be stronger in persons with compromised sensorimotor function than those with preserved sensorimotor function. We analyzed 601 cognitively normal (Mini-Mental State Examination ≥24 or free of cognitive impairment/dementia) Baltimore Longitudinal Study of Aging participants aged 50 or older with concurrent data on hearing (better ear pure-tone average [PTA]), mobility (6 m usual gait, 400 m endurance walk), and neuropsychological function including attention via Trail Making Test (TMT)-A, executive function via the difference between TMT-A and B, and Digit Symbol Substitution Test, and manual dexterity via Pegboard performance. We examined the association of PTA, each cognitive measure, and their interaction with mobility using multivariable linear regression, adjusted for covariates. After covariate adjustment, there were significant interactions between PTA and all cognitive measures in the association with 400 m endurance walking speed as the outcome. There was also a significant interaction between PTA and pegboard nondominant hand performance in the association with 6 m gait as the outcome. In all these cases, the PTA-mobility relationship was stronger among participants with lower cognition. Impaired hearing more strongly relates to poor mobility among those with compromised neuropsychological performance, especially manual dexterity reflecting the motor-cognitive interface and sensorimotor function, than those with preserved neuropsychological performance. Future longitudinal studies are needed to test whether hearing impairment more strongly predicts mobility decline over time in older persons with compromised neuropsychological function.