Effects of aging on adult hand function.

The effects that normal aging have on adult hand function and functional performance are not well understood. An empirical study was conducted examining relationships between prehension pattern type and frequency, hand strength, and performance time in functional tasks. Four groups of 10 adults were selected by age and gender, ranging from 24 to 87 years. Subjects were asked to pour milk into a cup and remove money from a wallet while being videotaped. Prehension patterns were identified with a functionally based classification system. Grip and three types of pinch were measured with a dynamometer and a pinch gauge. Prehension pattern selection did not seem to differ with age. Statistically significant differences in age were found for prehension pattern frequency, hand strength, and performance time. Nondysfunctional older subjects were observed resetting identical prehension patterns secondary to lateral pinch weakness, which contributed to increased prehension pattern frequency and performance time. Hand function seemed to remain stable until age 65 years, after which it diminished slowly. After age 75 years, age differences in performance were most apparent.