Effects of saccular function on recovery of subjective dizziness after vestibular rehabilitation

Objective: We attempted to investigate whether the integrity of saccular function influences the severity of subjective dizziness after vestibular rehabilitation in vestibular neuritis. Study Design: Retrospective analysis. Setting: Tertiary referral center. Patients: Forty-six patients with acute unilateral vestibular neuritis were included. Interventions: Diagnostic, therapeutic, and rehabilitative. Main Outcome Measures: All the patients completed vestibular rehabilitation therapy until their computerized dynamic posturography and rotary chair test results were significantly improved. The rehabilitation patients were classified into the normal to mild subjective dizziness and moderate to severe subjective dizziness groups according to the dizziness handicap inventory score (cutoff of 40). Differences between the two groups were analyzed. Results: After rehabilitation, 32.6% of the patients still complained of moderate to severe dizziness. Age, sex distribution, the presence of comorbidities, caloric weakness, pre-and postrehabilitation gain values in rotary chair test, postrehabilitation composite scores in posturography, and the duration of rehabilitation were not significantly different between the two groups. However, initial dizziness handicap inventory (DHI) score and composite score in dynamic posturography were worse and the proportion of patients with absent cervical vestibular-evoked myogenic potential in the moderate to severe group was much higher (93.3% vs. 35.5%, p<0.001). After multiple regression analysis of those factors, initial DHI score and absent cervical vestibularevoked myogenic potential response were identified as being associated with higher postrehabilitation DHI score. Conclusion: Saccular dysfunction in acute vestibular neuritis can contribute to persistent subjective dizziness, even after the objective parameters of vestibular function tests have been improved by vestibular rehabilitation.