Are deficiencies in manual tracking associated with upper extremity cumulative trauma disorders?

Objectives: To examine the reliability of manual tracking performance and its association with impairment and disability in individuals symptomatic of an upper extremity cumulative trauma disorder (CTD). Methods: Volunteer and physician referred subjects (100 control, 140 CTD) tracked a target cursor moving quasi-randomly using a hand-held stylus interfaced with a digitizing tablet. Impairment was physician-rated and the Disability of the Arm, Shoulder and Hand questionnaire measured disability. Subsamples of 25 subjects per group were tested on three occasions. Results: Reliability of tracking performance was excellent (ICC >= 0.88) and sensitivity was 81%. Performance was superior in controls (p < 0.001) and deteriorated as a function of impairment level (p < 0.001). Tracking and impairment rating explained 65% of the disability score. Conclusions: Tracking performance may be an important outcome for monitoring change over time and the impact of a CTD on function in everyday activities.