The influence of motor and cognitive impairment upon visually-guided saccades in Parkinson's disease

► We examined visually-guided saccades in 163 people with Parkinson's disease. ► Hypometria was primarily associated with motor impairment. ► Prolonged latency was associated with both motor and cognitive impairment. ► Hypometria occurs early in the disease process. ► Prolonged latency may be associated with later cortical-level pathology.