Oculomotor and oculovestibular functions in a hemispherectomy patient.

Oculomotor and oculovestibular functions in a patient who had undergone a left hemispherectomy were examined under a variety of visual and vestibular stimuli. The main findings were an inability to hold left eccentric gaze, resulting in gaze-evoked nystagmus to that side; inaccurate saccades to the right; defective smooth pursuit to the left; asymmetrical vestibulo-ocular responses (VOR) in the dark due to the interaction of the VOR with the "spasticity of conjugate gaze", decreased gain of the visuo-vestibulo-ocular reflexes to both sides, more marked to the right, when rotated fixating on a stationary wall target or the environment, due to abnormal smooth and optokinetic systems; and failure to inhibit the VOR when rotated to the left with visual fixation.