Carey, James R.

The purpose of this study was to examine the effects of age, sex, and hand preference on precise control of voluntary movement at the index finger metacarpophalangeal joint in able-bodied volunteers. An electrogoniometer was attached to this joint and connected to a computer. The computer screen displayed a sine wave target that each subject attempted to track with careful extension and flexion finger movements. Accuracy index scores were calculated for the extension phases, flexion phases, and the total sine wave. Each subject performed three tracking trials and the average for each of the above scores was computed. The results showed that younger subjects tracked significantly more accurately than older subjects and men tracked significantly more accurately than women. Also, the subjects tracking with the nonpreferred hand (15 right, 105 left) tracked significantly more accurately than those subjects tracking with the preferred hand (112 right, 8 left) in the flexion phases of the test. The data from these able-bodied subjects provide a base for comparison of patients' data, which may be helpful in the early recognition and monitoring of problems with precision in movement control.

The purpose of this study was to determine whether there are stimulus-response (S-R) compatibility effects in a manual tracking task for male and female subjects of different ages. 20 healthy men and 20 healthy women in each of three different age groups (20 to 39, 40 to 59, and 60 to 79 years) participated (total N=120). Subjects performed extension and flexion movements of the index finger metacarpophalangeal joint to track a computer-screen cursor along a target sine wave. The hand and forearm were positioned so that the finger movement was either vertical or horizontal, and the computer monitor was positioned so that the voluntary cursor movement was either vertical or horizontal. Each subject performed four different tracking tests corresponding to the four different ensembles of hand-forearm position and monitor position. There were significant differences in tracking performance between test ensembles in both women and men aged 60 to 79 years, and the compatible ensembles showed the superior performance. The results suggest that S-R compatibility effects exist in elderly women and elderly men performing a finger-movement tracking task, and these effects are consistent with impaired information processing in elderly persons. More research is needed on how S-R compatibility affects performance in persons with cerebral lesions.