The effects of visual, auditory, and mixed cues on choice reaction in Parkinson's disease

We investigated the effects of visual, auditory, and mixed cues on complex choice reaction in people with Parkinson's disease (PD). The paradigm using a computerized task was based on a game, "paper-rock-scissors." Four types of sensory cues were employed: simple visual cues, auditory cues, visual cues with auditory distracters, and auditory cues with visual distracters. Subjects were instructed to win, draw, or even lose the games and were required to respond as soon as possible after the sensory cues. When bradykinesia was taken into account, the PD patients had slower motor reactions. Further, when asked to lose in response to auditory cues, they displayed a significant delay in cognitive processing as compared to the healthy controls (HC), with a greater delay in the presence of a visual distracter. The error rates in the PD group were significantly higher than those in the HC group. These results suggest that PD patients are more influenced in choice reaction than the HC and by visual rather than auditory cues, especially under conditions with stimulus-response incompatibility that requires overriding habitual behavior. These data may be helpful in designing effective rehabilitation programs for PD to avoid inhibition of overlearned and contextually compatible reactions with visual distracters. (C) 2008 Elsevier B.V. All rights reserved.