Otolith dysfunction in vestibular neuritis - Recovery pattern and a predictor of symptom recovery

Objectives: 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. Methods: 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. Results: 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. Conclusion: 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.