Speech Perception in Noise After Cochlear Implantation for Single-Sided Deafness

Importance: There is a lack of high level of evidence studies comparing the effect of different treatment options for single-sided deafness (SSD). Objective: To determine the effect of a cochlear implant (CI), bone conduction device (BCD), contralateral routing of signals hearing aid (CROS), and no treatment on speech perception in noise outcomes in patients with SSD. Design, Setting, and Participants: In this single-center randomized clinical trial, adult patients with SSD were randomized into 3 groups: CI; a trial period with first a BCD on a headband and then a CROS; or a trial period with first a CROS and then a BCD on a headband. After the trial periods, patients opted for a BCD, CROS, or no treatment. Measurements were completed at baseline and at 3, 6, 12, and 24 months of follow-up. Data were collected from July 2014 to October 2021, and data were analyzed from December 2022 to May 2023. Interventions: CI, BCD then CROS, or CROS then BCD. Main Outcomes and Measures: The primary outcome was the speech reception threshold in noise (SRTn), measured with speech and noise from the front (S0N0), speech directed to the poor ear and noise to the better ear (SpeNbe), and vice versa (SbeNpe). The secondary outcome was disease-specific quality of life (QOL). Results: Of 120 included patients, 60 (50.0%) were female, and the mean (SD) age at inclusion was 53.0 (12.1) years. At the start of follow-up, 28 patients received a CI, 25 a BCD, 34 a CROS, and 26 chose no treatment. At 24 months, the CI group had significantly better speech perception in noise scores than the BCD group (difference in SRTn: SbeNpe, -4.7 dB; 95% confidence interval, -6.6 to -3.0; SpeNbe, -2.2 dB; 95% confidence interval, -4.6 to -1.1), the CROS group (difference in SRTn: S0N0, -1.3 dB; 95% confidence interval, -1.7 to -0.2; SbeNpe, -5.3 dB; 95% confidence interval, -6.0 to -3.1), and the no treatment group (difference in SRTn: SpeNbe, -6.3 dB; 95% confidence interval, -7.5 to -4.9). Compared with the no treatment group, the BCD and CROS groups showed significantly better (difference in SRTn for SpeNbe, -4.1 dB [95% confidence interval, -5.2 to -1.5] and -4.1 dB [95% confidence interval, -6.1 to -3.3], respectively) or worse (difference for SbeNpe, 4.0 dB [95% confidence interval, 2.6 to 6.2] and 4.6 dB [95% confidence interval, 2.8 to 5.7], respectively) speech perception in noise. Self-reported speech perception abilities were significantly better for the CI group compared with the BCD, CROS, and no treatment groups. Conclusions and Relevance: In this randomized clinical trial, the CI group outperformed the BCD, CROS, and no treatment groups in terms of speech perception in noise and disease-specific QOL in patients with SSD after 24 months of follow-up. These results indicate that patients with SSD can partially regain the advantages of binaural hearing after treatment. Trial Registration: trialregister.nl Identifier: NL4457.