Otolith dysfunction in vestibular neuritis

Abstract

To prospectively follow patients with vestibular neuritis (VN), to compare the recovery pattern of canal and otolith dysfunction, and to determine which tests best predict symptom recovery. Between March 2006 and December 2006, 51 consecutive patients with unilateral VN were enrolled within 7 days of onset (average 3 days). Otolith function tests included ocular torsion (OT), subjective visual vertical (SVV), and vestibular evoked myogenic potential (VEMP), and canal function tests included head-shaking nystagmus (HSN), caloric stimulation, and head-thrust testing. Patients returned for two follow-up evaluations at approximately 1 week and 6 weeks after the initial evaluation. On the first examination, all patients had abnormal HSN, caloric, and head-thrust test results, and at least one otolith-related test abnormality: abnormal tilt of SVV (48/51, 94%), abnormal OT (42/51, 82%), or abnormal VEMPs (25/51, 49%). The degree of SVV tilts correlated with the degree of OT for one or both eyes (p < 0.05). Skew deviation was observed in 7 patients (14%), and a complete ocular tilt reaction was detected in only 2 patients. On follow-up, otolith test results returned to normal more rapidly than canal test results. The head-thrust test was the best predictor of symptom recovery. Eighty percent of patients who continued to report dizziness at the last follow-up visit had a positive head-thrust test result, whereas only 10% of patients who were not dizzy had a positive head-thrust test result. Otolith-related test abnormalities improve more rapidly than canal-related test abnormalities after vestibular neuritis. If patients have a positive head-thrust test result on follow-up, they are more likely to be dizzy.