Tracking ability of hemiparetic and healthy subjects.

The purpose of this descriptive study was to investigate differences in tracking ability between the involved and uninvolved hands of hemiparetic (n = 10) and healthy (n = 10) subjects. The subjects tracked a sine-wave target pattern by flexing and extending their index finger metacarpophalangeal joints. The amplitudes of the target patterns were proportional to each subject's active range of motion. The root-mean-square (RMS) of the vertical distance between the target and response lines was expressed as a percentage of the RMS of the target pattern and subtracted from 100 to give an index of each subject's accuracy. The authors used t tests to compare the uninvolved and involved hands of the hemiparetic subjects (p greater than .05), the dominant and nondominant hands of the healthy subjects (p greater than .05), and the uninvolved hands of the hemiparetic subjects with the dominant hands of the healthy subjects (p less than .005). This study indicates that within the available active ROM, finger tracking ability is impaired bilaterally in hemiparetic subjects. The implication for physical therapists is that treatment strategies for improving motor control should be directed bilaterally.