Abnormal antisaccades and smooth pursuit eye movements in patients with Wilson's disease

Neurological symptoms in Wilson's disease (WD) may include oculomotor abnormalities. However, to date, eye movements in WD patients were rarely investigated and the data concerning this issue are sparse. The purpose of this study was to evaluate reflexive and voluntary eye movements in WD patients. We examined horizontal saccadic and smooth pursuit eye movements using infra-red oculography in 50 WD patients, including 29 neurologically symptomatic (WDn) and 21 asymptomatic ones (WDa), and in 29 healthy controls. We found statistically significant increase in mean antisaccadic latency (378 ms) and in mean antisaccadic error rate (22.5) in the WDn group, when compared with WDa group (317 ms and 9.1, respectively) and controls (318 ms and 9.7, respectively). In contrast, there were no statistically significant differences in mean latency of prosaccades and in size of the gap effect. Patients with neurological manifestations had also abnormal smooth pursuit-increased number of saccadic intrusions (mean: 8.6) and decreased gain (mean: 0.69) comparing with WDa patients (4.1 and 0.83, respectively) and controls (2.2 and 0.91, respectively). The data suggest that WD is associated both with impairment of voluntary control of saccades and with disturbed smooth pursuit eye movements while reflexive saccades seem to be preserved.