Background: The integrity of frontal systems responsible for voluntary control and their interaction with subcortical regions involved in reflexive responses are studied in Parkinson's disease (PD) patients. Previous studies have shown PD patients have impaired executive function including deficits in attention, motor planning, and decision-making.
Methods: Executive function was measured through eye movements: reflexive (stimulus-driven) prosaccades and voluntary (internally-guided) antisaccades. Patients with advanced idiopathic PD, OFF and ON their optimal levodopa therapy, were tested on a prosaccade and an antisaccade task and compared to matched controls.
Results: Levodopa significantly increased response time for reflexive prosaccades and reduced error rate in voluntary antisaccades.
Conclusions: Consistent with our proposed model, PD patients in the medicated state are better able to plan and execute voluntary eye movements. These findings suggest levodopa improves function of the voluntary fronto-striatal system, which is deficient in PD.
- Parkinson's disease
- executive function
- prefrontal cortex