Comparison of Huntington's and Parkinson's Disease Patients' Use of Advance Information

Neurologically intact subjects respond more quickly in a choice response time (CRT) task if they are told beforehand which signal will appear. Previous studies with Parkinson's disease (PD) patients are equivocal as to whether patients benefit from such cues. This experiment provided several convergent measures of the use of advance information in the motor responses of PD patients and also compared their performance to patients with striatal atrophy due to Huntington's disease (HD). Nine early PD patients, 8 early HD patients, 5 moderate HD patients, and 16 neurologically intact control subjects performed a simple response time (SRT) task and 3 CRT tasks: 1 without a cue as to where the GO signal would appear, 1 with a cue subjects watched, and 1 with a cue to which subjects responded. PD patients and HD patients showed a benefit in response times equal to that of control subjects in all conditions.