Clinical significance of rebound nystagmus.

OBJECTIVE/HYPOTHESIS: Magnetic resonance imaging (MRI) examination is performed in cases of rebound nystagmus to elucidate the responsible site for rebound nystagmus.

METHODS

Patients with vertigo or tinnitus received a battery of audiological and neuro-otological tests. Those who had rebound nystagmus were rechecked by electronystagmography and examined by MRI.

RESULTS

Ten patients had a second-degree nystagmus evoked by changing direction of fixation, from the lateral to the forward gaze. All patients displayed positive MRI findings in cerebellum or brainstem, including tumor in seven cases and stroke in three cases. Moreover, in seven of eight cases with unilateral lesions, rebound nystagmus was ipsilateral with respect to the side of the lesion.

CONCLUSION

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.