Combined Amplification and Sound Therapy for Individuals With Tinnitus and Coexisting Hearing Loss: A Retrospective Cohort Study

BACKGROUND: The heterogeneity of tinnitus perception and its impact necessitates a tailor-made management approach in everyone. The current study examined the effects of residual inhibition in combined amplification and sound therapy in individuals with tinnitus and coexisting hearing loss. METHODS: A retrospective analysis was performed on patients with tinnitus and coexisting hearing loss between 2016 and 2019. A total of 72 patients provided with combined amplification and sound therapy were divided into 3 groups based on residual inhibition: (i) complete residual inhibition, (ii) partial residual inhibition, and (iii) negative residual inhibition. Tinnitus severity was measured using the Tinnitus Functional Index before treatment and 1 and 6 months after the intervention. A multilevel mixed-effects model was used to examine the treatment effects including both the main and interaction effects of time and residual inhibition on the tinnitus severity. RESULTS: Of the 72 participants, 55 (76%) and 61 (85%) had clinically significant changes (13 points in Tinnitus Functional Index) at 1-month and 6-month postintervention, respectively. In the complete, partial, and negative residual inhibition groups, the reduction in tinnitus impact was 100%, 78%, and 74%, respectively. A multilevel mixed model analysis showed that the main effects of time and residual inhibition along with their interaction were significant. CONCLUSIONS: The study results suggest that combined amplification and sound therapy is beneficial in individuals with tinnitus and coexisting hearing loss in reducing their tinnitus severity, and this benefit was more in individuals with complete residual inhibition. However, these results need to be further confirmed by controlled trials.