Electroacoustic Hearing: An exploratory study into the candidacy and benefits of electroacoustic devices in New Zealand

Abstract

Introduction: Improvements in hearing preservation (HP) with cochlear implantation has culminated in the expansion of cochlear implant (CI) candidacy to include those with residual low frequency hearing and the emergence of electroacoustic devices that combine both electrical and acoustic stimulation (EAS). EAS has been shown to provide greater improvements in speech perception compared to electrical stimulation alone and aims to target those with precipitously sloping sensorineural hearing losses. The number of potential and current recipients who may benefit from this technology has yet to be explored in New Zealand (NZ). Aims: This research was divided into two parts. The first was focused on assessing the knowledge of practicing audiologists in NZ surrounding EAS and management of the precipitously sloping hearing loss population. Additionally, it aimed to estimate how many potential candidates could be eligible for this technology. The second aimed to retrospectively evaluate factors influencing HP and EAS device use. Benefits between the EAS and electric only fitting were then investigated and compared. Methods: Data was collected from 48 NZ Audiological Society (NZAS) recognised audiologists. An anonymous questionnaire was administered consisting of 16 questions. Chart review of adult recipients within the CI programme revealed very few candidates with pre-operative residual hearing had undergone implantation in the programme’s history. A review of one individual evaluating pre and post-operative hearing and factors influencing HP success was completed. EAS devices were then fit and benefit was assessed using CNC and AZBio speech perception tests and the SSQ-C questionnaire following a two-week trial period. Results: Limitations in audiologist knowledge of EAS device candidacy were identified and most audiologists were satisfied with the management of precipitously sloping hearing loss clients with hearing aids (HAs). For one CI recipient reviewed, implementation of soft surgical techniques resulted in HP levels similar to those found in literature. Benefits in speech perception in noise was observed with EAS compared to electric stimulation, but not in quiet. Slight subjective improvements were noted. Conclusions: This research highlights the need for improved management of the precipitously sloping population and demonstrates the potential use of a device that shows an improvement in outcomes.