Electro-oculographic study of saccadic pursuit eye movements in patients with brain lesions

Abstract

Electrooculograms were recorded in 36 patients with either left or right hemisphere lesions and in 20 normal adults during eye movements on command, slow pursuit eye movements and during induced optokinetic nystagmus (OKN). In all patients the command eye movements produced electrooculograms similar to those of normal subjects, a fast one-step movement. Saccadic pursuit eye movements were a constant finding in cases with posterior hemispheric lesions, but they were exceptionally recorded in normals. They were more numerous when the lesion was located in the right hemisphere. Unidirectional saccadic movements were most frequently recorded, particularly during following to the right. Bidirectional eyes saccades were rare, but a combination of uni- and bi-directional (mixed type) was commonly seen. In patients with posterior hemispheric lesions the saccadic pursuit potentials were usually recorded in both right and left following directions; rarely in one direction only. The direction of the saccadic pursuit potentials was always related to the direction of the moving target. The horizontal OKN was asymmetric in 29 cases and symmetric in 7 cases. In the asymmetric group, all cases, with the eception of one, showed saccadic pursuit. Of those with a normal or symmetric OKN response 5 showed saccadic pursuit and 2 showed smooth or normal following. When present an abnormal OKN was to the side contralateral to the lesion. In normals the optokinetic response was symmetric. The relationships of saccadic pursuit and OKN are discussed with reference to brain localization of lesions.