Saccadic oscillations associated with the quick phases of caloric nystagmus in severe diffuse brain damage

Caloric nystagmus patterns associated with ocular dysmetria, ocular flutter or flutter dysmetria were studied in ten patients being in a vegetative state, among whom were 9 patients with head injury and 1 with complications caused by a grand mal status. Brain damage was complicated by hypoxemia and especially by brain stem herniation. It was more often observed in very young children and appears to be associated with a poor clinical course. Physostigmine seems to have an activating and provocating effect on these saccadic oscillations. In view of Zee and Robinson's hypothesis on the pathophysiology of saccadic oscillations, it is suggested that these nystagmus patterns may reflect a disturbance of brain stem midline structures (pausing neurons) or an abnormal supranuclear (cerebellum) control.