ISOMETRIC PINCH FORCE CONTROL AND LEARNING IN OLDER ADULTS

The learning of a dynamic isometric pinch force task was investigated in young adults (aged 19 to 29 years) and older adults (aged 64 to 75 years) through use of a visuo-motor tracking paradigm. Both groups sig nificantly improved performance over trials, retained what was learned 1 week later, successfully transferred to a new target, and demonstra ted interlimb transfer of training effects, reflecting a strong centra l component to this task that is apparently intact in older adults. Ho wever, performance differences between the two groups remained through out the trials. Although it appeared that older adults were able to ut ilize a model-based strategy to predict the target path, as evidenced by minimal response lag, their absolute performance was inferior to th at of young adults relative to an overall root mean square error score , a correlation coefficient, and their increased use of high-frequency components in the tracking signal. The age-related performance differ ences may be attributable to a peripheral decrement in tactile sensibi lity and/or muscle reorganization as well as a slowness in processing afferent information.