Investigations of upper extremity visuomotor control performance measures

The need to characterize upper-extremity performance is prompted by significant clinical as well as industrial applications. A performance measurement strategy based on engineering principles is described. Measures of movement speed, reaction speed, and coordination are obtained with a computer-based tracking task protocol to complement strength and range of motion measures. Proposed measures were evaluated in distinct studies. The first study, aimed at evaluating the stability and the discrimination power of seven initial measures, involved 165 normal and 32 Parkinson patients and was carried out over a period of five years. Based on a need for further performance characterization, five additional measures were developed. A second study, involving 15 normal subjects, was conducted to investigate both short and long term reliability for an expanded set of measures. Results of these studies demonstrate effective quantification of performance in both normal subjects and Parkinson patients and document reliability and discriminatory power of the measures. Measurands are discussed with regard to their interpretation in general human-task interface situations.