Different time course of compensation of subjective visual vertical and ocular torsion after acute unilateral vestibular lesion.

PURPOSE: Time course of the recovery of otolithic dis-function caused by superior vestibular neuritis has been examined in fifteen patients. METHODS: The subjective visual vertical (SVV) and the ocular cyclotorsion (OT) have been measured four times after the acute episode up to 1 year RESULTS: In most of the patients the SVV tilt returned to control values within few months (3-6 months) after the acute episode, while OT remained out of normal range in almost all patients a year later. CONCLUSION: The abnormal OT observed after 1 year from the acute episode of vestibular neuritis, suggests that the otolithic receptors remained altered for several months and the OT may be a good indicator of the entity of the residual peripheral otolithic lesion. Moreover, the dissociation between the SVV tilt recovery and that of OT supports the issue that the two signs of the otolithic disfunction are only partially linked each other with centrally or peripherally distinct re-balancing circuits.