Long-term outcome of canal paresis of a vascular cause.

There have been several reports on the progress of the caloric response of vestibular neuritis, but little is known about the recovery of canal paresis (CP) of a vascular cause. This study found that the caloric response normalised in 20 (67%) of 30 patients with CP associated with posterior circulation ischaemic stroke who were followed for at least 1 year (mean, 42.5 months; range, 14-85 months). The most commonly infarcted territory on brain MRI associated with CP was in the distribution of the anterior inferior cerebellar artery (26/30, 87%). None of the patients who were followed for >5 years after the onset of vertigo showed persistent CP. Residual dizziness did not differ significantly between patients with or without CP at the final follow-up. These findings suggest that CP associated with posterior circulation ischaemic stroke often has a good long-term outcome. Following patients for at least 5 years increases the likelihood of normalisation of the vestibular response to caloric stimulation.