Audiologic limitations of Vibrant Soundbridge device: Is the contralateral hearing aid fitting indispensable?

Abstract

OBJECTIVES/HYPOTHESIS: The purpose of this study was to evaluate the audiologic limitations of the Vibrant Soundbridge (VSB) implant and the benefits of contralateral hearing aid (HA) fitting in VSB recipients.

STUDY DESIGN: Retrospective study.

METHODS: Twenty-three patients with symmetrical sensorineural or mixed hearing loss were enrolled in this study. The patients underwent VSB implantation in one ear and HA fitting in the other. Aided pure-tone audiometry was performed to measure the functional gains of each device. The Korean version of the Hearing in Noise Test (K-HINT) was used to determine the sentence speech perception in a quiet environment and the signal-to-noise ratio (SNR) in a noisy environment.

RESULTS: VSB implantation resulted in hearing gains comparable to that of conventional HAs at high frequencies, whereas the functional gains at low frequencies were not satisfactory in the mixed hearing loss group. In these patients, the contralateral HA sufficiently amplified the low frequencies. The results of the K-HINT of the SNR in the VSB-aided ear were not significantly improved when compared to HA-aided contralateral ear. However, binaural fitting of a VSB and HA resulted in substantially improved SNR when compared to the unaided condition. This improvement of the SNR strongly correlated with functional gains at low frequencies in the contralateral HA-aided ear.

CONCLUSIONS: Although unilateral VSB implantation is limited in terms of low-tone enhancement and speech perception in noisy environments, contralateral HA fitting can overcome these limitations and increase the efficacy of hearing rehabilitation.

LEVEL OF EVIDENCE: 4