Rate of information processing in patients with Wilson's disease.

This study investigated the rate of information processing, independent of motor speed, in neurologically affected Wilson's disease (WD) patients. Two scanning tasks based on the Sternberg item-recognition paradigm were administered to 17 neurologically symptomatic WD patients and 17 normal control (NC) subjects. Although WD subjects do have longer response latencies than NC subjects, their rate of information processing is the same as the rate of the NC subjects. The longer response latencies are attributable to their motor deficits. The clear impact of motor impairment on test performance underlines the necessity for specialized assessment measures that can accurately reflect the cognitive abilities of motor-impaired patients. These findings suggest that Wilson's disease is not characterized by slowed information processing.