Clinical Significance of Rebound Nystagmus

Abstract

Rebound nystagmus implies a lesion in cerebellum or brainstem for which MRI examination is 100% sensitive. It has a certain lateralizing value, with its direction away from the lesioned side.

A clinical and genetic study in a large cohort of patients with spinocerebellar ataxia type 6

“…There has been one report of extensive Purkinje cell loss affecting most of the cerebellar cortex, including the flocculus, in SCA6 patients (Gomez et al 1997). Our neuro-otological findings suggested lesions in the vermis, flocculus, paraflocculus or nodulus with sparing of the paramedian pontine reticular formation, and these findings were consistent with the purely cerebellar disorders of eye movements in previous reports (Zee et al 1981;Henn et al 1984;Fetter et al 1994;Moschner et al 1994;Buttner and Grundei 1995;Buttner et al 1998;Burk et al 1999;Lin and Young 1999). Further studies will be necessary to confirm the relationship between anatomical lesions and the neuro-otological features of SCA6, especially the relationship between DPN and lesions of the flocculus or nodulus.…”

Disorders Affecting the Fourth Ventricle

“…Rebound nystagmus occurs when a patient returns the eyes to the primary position after a prolonged attempted eccentric gaze. It implies a lesion in the cerebellum or brainstem, with its direction away from the lesion side (17,18). Regarding the downbeat nystagmus, it has long been recognized as a sign of the posterior fossa lesion, and its occurrence in the flocculectomized monkey suggests a possible anatomic locus (19,20).…”

Oculomotor involvement in myotonic dystrophy type 2

“…The test can be made more sensitive by testing patients in complete darkness, as in this situation visual fixation and tracking mechanisms cannot be used to suppress the nystagmus. Although rebound is generally thought to be a specific sign for brainstem or cerebellar disease, 7,10,15 it can be observed in normal persons who hold gaze for long periods (e.g., 40 seconds) and, in such cases, the subjects tend to have endpoint nystagmus. Seven of eight of our patients had strong rebound nystagmus, but none had endpoint nystagmus.…”