抄録
Optokinetic nystagmus (OKN) and smooth pursuit eye movement were studied in fifteen patients with a brain tumor.
In the patients with a cerebellar tumor, OKN was normal at lower stimulus velocities and substantially diminished at higher stimulus velocities, while in the patients with a brainstem tumor, it was almost completely abolished at all the stimulus velocities. In these patients, saccadic eye movement occurred instead of smooth pursuit eye movement during the eye tracking test.
In one patient with a VIIIth nerve tumor localized within the porus acusticus internus, OKN was diminished at higher stimulus velocities and smooth pursuit eye movement was normal.
It was concluded that a neuronal circuit in the brainstem was responsible for eliciting OKN at lower stimulus velocities, that the cerebellum provided a neuronal circuit for eliciting OKN at higher stimulus velocities and that peripheral vestibular nerve inputs produced OKN of human beings.
