Initiation of visual-guided random saccades and remembered saccades in parkinsonian patients with severe motor-fluctuations.

We studied the initiation of saccades to visual-guided random time and remembered targets in a group of nine Parkinsonian patients with severe motor fluctuations and in 9 age matched control subjects. In contrast to a marked skeletomotor improvement during the "on" condition, saccadic latencies for both visual-guided random saccades and remembered saccades were increased in the patients during the "on" condition compared to the "off" condition. This result of dissociation between skeletomotor and oculomotor function indicates that common concepts of saccadic initiation in parkinsonian patients do not hold true in patients with severe fluctuations since dopaminergic stimulation seems to increase saccadic latencies in these patients.