Physiological correlates of age-related decline in vibrotactile sensitivity.

The purpose of this study was to describe age-related changes in vibrotactile sensitivity in participants of the Baltimore Longitudinal Study of Aging and to identify factors that are associated with impairment in vibrotactile sensitivity independent of age. Participants (n=523, age: 26-95 years) underwent measurements of vibration perception threshold (VPT, 100Hz) under the 2nd metatarsal head, glucose tolerance, serum inflammatory markers, nerve conduction parameters, movement time and cognition. Univariate and multivariate regression analyses were performed to identify factors that predicted VPT independent of age. Structural equation modeling was used to describe relationships between these variables. VPT was progressively higher with older age. Adjusting for age and height, VPT was similar in men and women and the slope of age-related decline was similar in the two genders. Age, height, peroneal nerve conduction velocity and peroneal nerve amplitude were independent predictors of VPT. Structural equation model demonstrated a direct relationship between peripheral nerve function and VPT. Height and circulating inflammatory markers may influence age-related decline in vibrotactile sensitivity through their negative impacts on peripheral nerve function.