Reflexive and voluntary saccades in Parkinson's disease

Objective: To evaluate the characteristics of saccadic eye movements in patients with Parkinson's disease(PD).

Methods: 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.

Results: 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.

Conclusions: 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.