Evaluation of Amplification Systems for Sound Localization and Speech Perception in Single-Sided Deafness: A Comparative Study With Low-Frequency Stimulus.

Purpose: This study aimed to evaluate the impact of different hearing devices on sound localization and speech perception in individuals with single-sided deafness (SSD). Specifically, the study sought to assess the performance of softband bone-anchored hearing aids (BAHAs) and contralateral routing of signals hearing aids (CROS HA) in various conditions to determine their effectiveness in improving auditory outcomes for SSD patients.

Method: Eighteen participants (aged between 20 and 50 years) with SSD underwent tests using softband BAHA, CROS HA, and unaided conditions in a counterbalanced design. Sound localization tests, speech perception in noise assessments, and subjective satisfaction ratings were conducted to measure the effectiveness of the hearing devices. The study employed a single-subject, repeated-measures experimental design to compare the performance of the different devices.

Results: The results revealed that softband BAHA significantly improved sound localization, particularly in low-frequency stimulus localization, compared to CROS HA and unaided conditions ( = .03). Subjective satisfaction scores aligned with objective test outcomes, indicating a preference for softband BAHA. Speech perception in noise performance varied across conditions, with both hearing devices showing benefits in certain scenarios.

Conclusions: The findings of this study have important clinical implications for selecting appropriate hearing device options for SSD patients. Softband BAHA demonstrated superior performance in sound localization tasks, as evidenced by the significant improvement observed in the Azimuth Localization Test results. This test measures a central auditory skill-sound localization-by evaluating participants' ability to accurately identify the direction of sound sources. The enhanced performance with softband BAHA in this task suggests that the BAHA device provides the brain with more robust cues for localization when compared with the CROS device. Using suitable hearing devices during rehabilitation for SSD patients is crucial for enhancing auditory outcomes and quality of life in this population. Further research is warranted to address the limitations identified and optimize rehabilitation strategies for individuals with SSD.