It is known that gaze-evoked nystagmus, upbeat nystagmus, down beat nystagmus and pure rotatory nystagmus are associated with central lesions, but these types of nystagmus do not always appear in the acute phase of vertigo in patients with a central disorder. In this study, we retrospectively investigated acute phase nystagmus in 15 patients with cerebrovascular lesions. All patients were attending an ENT clinic because of a lack of marked findings concerning neurological dysfunction except vertigo, but finally they were diagnosed as having vascular lesions in the posterior fossa, 3 patients with medulla infarction, 3 patients with pons infarction, 8 patients with cerebellar infarction and 1 patient with cerebellar hemorrhage.
At the initial visit to the ENT clinic, spontaneous nystagmus was observed in all patients with a brainstem infarction and in 3 out of 9 patients with cerebellar lesions. Their nystagmus was the horizontal type or the horizontal type with a torsional component. All patients initially were suspected of having peripheral lesions at the initial visit or on admission, but the direction and the type of nystagmus changed periodically and neurological symptoms except vertigo appeared subsequently to admission. Diagnosis of central lesion was made with MRI. It is difficult to differentiate central lesions from peripheral lesions on the grounds of the direction and type of nystagmus, but it is important to observe the changes in nystagmus and other neurological findings for the differential diagnosis of central lesions.
