PP802 - A Retrospective Study for Binaural Speech Perception Trends in Listeners with Hearing Aids and Cochlear Implants

Abstract:
Much progress has been made in binaural speech perception for listeners with hearing aids (HAs) and/or cochlear implants (CIs). However, there remains significant variability in the benefits of the two devices, with some patients showing little benefit or poorer performance for speech perception compared to either ear alone. The goal of this study is to investigate different patterns of HA and CI users' binaural speech perception. Through retrospective data analysis, we look at individual cases where underlying binaural interferences may be prohibiting a patient’s ability to communicate to the best of their ability.

Summary:
Rationale/Purpose
A nuanced exploration into the individualized facets of binaural advantages and disadvantages remains an under-explored terrain in both research and clinical practice. In other words, a profound understanding of binaural and monaural benefits holds the potential to enhance various aspects of binaural speech perception significantly. This study aimed to explore binaural perception trends in hearing aid (HA) and/or cochlear implant (CI) users by using retrospective data analysis of their monaural vs. binaural speech perception scores. Retrospective data from 172 CI users and 82 HA users in two audiology clinics in Kentucky (University of Louisville Hospital and Heuser Hearing Institute) were collected. They were divided into three groups: those who used two HAs (bilateral HA), those who used two CIs (bilateral CI), and 3) those who used bimodal stimulation (a CI with a contralateral hearing aid: bimodal CI). Subjects’ demographic information (age, sex, duration of hearing loss, amount of residual hearing, duration of hearing device use), pure tone audiometry, and speech perception score (AzBio in quiet) were examined. In particular, the subjects' monaural and binaural speech perception scores were analyzed to explore binaural speech perception trends.

Results
The results showed that four distinct binaural speech perception trends were observed in all three subject groups: 1) binaural benefit; 2) binaural averaging; 3) binaural interference; and 4) better-ear dominance. Within the bilateral HA group, the binaural benefit trend was the most dominant at 55 percent, the better ear trend was 27 percent, the binaural averaging trend was 17 percent, and only 1 percent of subjects exhibited binaural interference trends. Within the bimodal CI group, the binaural benefit and better ear trends were similar at 37 percent and 34 percent, respectively, the binaural averaging trend was 17 percent, and an increased binaural interference trend (8 percent) was observed. Within the bilateral CI group, the better ear trend was relatively dominant (40 percent), and 27 percent binaural benefit, 20 percent binaural averaging, and 12 percent binaural interference trends were observed. Neither subject demographic data (i.e., residual hearing) nor audiometric thresholds did not explain those binaural speech perception trends within or between subject groups.

Conclusions
The presence of both binaural averaging and binaural interference trends implies that listening on two devices is not always better than one. Increased understanding of how binaural disadvantages (binaural averaging and binaural interference) affect speech perception for hearing-impaired users is clinically essential for the future design of training- and device-based rehabilitative strategies to increase the benefits of binaural processing for speech perception in quiet and noise. In addition, delving into the intricacies of individual binaural benefits is crucial for refining treatment strategies and tailoring services to the unique needs of each recipient, consequently bolstering speech perception and spatial hearing abilities. Such insights hold promise for addressing suboptimal outcomes, notable in mitigating instances of binaural interference.