The effect of aging on the synchronization of human arm movements to external events

The aim of this study was to analyze the synchronization of cyclical arm movements to an external event and to determine age-related differences when the coupling strength between perception and action is manipulated. A group of young and a group of older subjects had to track a moving light travelling horizontally while manipulating a lever in the same direction (in-phase) or in the opposite direction (anti-phase). The results showed a performance decrease for both age groups in the anti-phase condition as compared to the in-phase condition, yet this decrease was more pronounced for the older persons. Interestingly, this age effect disappeared with practice. Most likely the observed age-related performance decrement was due to the difficulties encountered by older people to correct on line movements when the visual information needed was not directly accessible. Nevertheless, this study also highlights the capacity of older people to regain the performance loss through training.