Time course of cognitive training in Parkinson disease.

BACKGROUND: People with Parkinson disease (PD) have difficulty initiating internally generated movements. We have shown that computer-based cognitive training can improve movement initiation. However, little is known about the optimal duration of training. OBJECTIVES: To determine the optimal training duration for computer-based neurorehabilitation of internally represented movement initiation in people with PD. METHODS: Nineteen PD and twenty-one age-matched control participants, ages 50-85 years, were included in analysis of pre- and post-training evaluation and 30 training sessions. Computer training consisted of cued and un-cued movement trials. The presentation of a cue (a combination of numbers on either the right, left or both sides of the screen) indicated that participants should respond by typing the numbers. Successful cued trials were followed by un-cued trials consisting of a green filled circle. Participants re-enter the cued sequence, thus producing an internally represented (IR) movement. The training was adaptive. Outcome measures were reaction time and error rate, and cumulative sum (CUSUM) analysis was used to identify peak training improvement. RESULTS: Participants with PD were divided into impaired (IPD) and unimpaired (UPD) groups, based on mean control group pre-training performance. All three groups showed improved RT and error rates for IR trials; however, the IPD group demonstrated significantly greater improvement in reaction time. Training was most effective in participants with greater disease severity and duration. Peak day of training improvement for the IPD group was 8 days. CONCLUSION: Optimal training duration was relatively short and the IPD group demonstrated the most gain, indicating that cognitive training should be tailored to individual needs.