Reflexive and Voluntary Saccades in Parkinson's Disease

Abstract

To evaluate the characteristics of saccadic eye movements in patients with Parkinson's disease(PD). Eye movements of 14 patients with moderate to advanced PD and 12 age-matched controls were recorded with an infrared system. Two kinds of saccade tasks were used: saccade tasks for eliciting reflexive saccades(visually guided saccades in the gap condition) and saccade tasks for eliciting volitional saccades(visually guided saccades, saccades in overlap condition, memory-guided saccades, and anti-saccades). Latency, accuracy, peak velocity, and other parameters of saccades were evaluated. Visually guided saccades and saccades in the gap condition were slightly hypometric in PD patients. Saccades in the short-term overlap condition were not impaired in PD patients. Increased mean latencies and decreased degrees of accuracy of memory-guided saccades, and increased error rates of the memory-guided saccade task were marked in PD patients. Error rates in the anti-saccade task were not increased in PD but the mean saccadic latencies were slightly increased. Reflexive saccades are preserved in PD, whereas memory-guided saccades are markedly impaired. But anti-saccades in a task for eliciting in volitional saccades are not impaired in PD.