Levodopa slows prosaccades and improves antisaccades: an eye movement study in Parkinson's disease.

Background: The integrity of frontal systems responsible for voluntary control and their interaction with subcortical regions involved in reflexive responses were studied in patients with Parkinson's disease (PD). Previous studies have shown that patients with PD 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.