Investigating the Role of Auditory Processing Abilities in Hearing Aid Outcomes Among Older Adults

Abstract

Background: Hearing aid outcomes are highly variable and important to improve. The overall objective of this dissertation is to determine how auditory processing assessments of temporal, spatial, and binaural processing are related to hearing aid outcomes in older adults. The long-term goal is to establish the evidence base supporting auditory processing evaluation as an expanded part of rehabilitative management to help target appropriate treatment and counsel on realistic expectations with recommendations not solely based on audibility alone. Methods: In this dissertation, three studies were undertaken. First, a systematic review, then clinical research in a patient population, finally a more detailed evaluation and comparison of speech-in-noise testing. In the first study, a systematic review was conducted to answer the question: “How do auditory processing abilities affect hearing aid satisfaction among adults?” Then in the second study, 78 older adults were recruited to take part in multiple evaluations of their auditory processing abilities and their non-auditory self-reports. Multiple linear regression was used to determine the strength of the relation between the different factors and hearing aid outcomes. In the third study, speech-in-noise results from the QuickSIN, Listening in Spatialized Noise Sentence Test (LISN-S), and a spatial release from masking task using the Coordinate Response Measure (CRM) materials, were evaluated and compared in 61 older adults from the second study. For this study, Pearson’s correlations, multiple linear regressions, and point-biserial correlations were used to evaluate and compare the three speech in noise tests. Results: In study one, seven studies met the inclusion criteria for the systematic review. Of these studies, the Dichotic Digits Test, the Synthetic Sentence Identification Test, and the Performance-Perceptual Test were the only tests of auditory processing ability that were significant contributors to hearing aid satisfaction. Although these studies were not rated highly for study quality, they do suggest the potential for associations between auditory processing abilities and hearing aid satisfaction. In study two, temporal processing as measured by the Gaps-in-Noise, spatial processing as measured by the LISN-S, and self-efficacy as measured by the Measure of Audiologic Rehabilitation Self-Efficacy for Hearing Aids (MARS-HA), were all statistically significant predictors of hearing aid satisfaction. However, contradictory to prior studies in the literature, binaural processing on the Dichotic Digits Test was not a significant predictor. For hearing aid benefit, only the MARS-HA and self-report of disability as measured by the Speech, Spatial, and Qualities of Hearing (SSQ) questionnaire were statistically significant predictors. In study three, Pearson’s Correlations showed that only the LISN-S and QuickSIN and the LISN-S and CRM were significantly correlated to one another. The SSQ score was not correlated with performance on any of the speech-in-noise tests. Finally, no correlations could be determined between subjective or objective testing and group aural rehabilitation attendance or assistive listening device use. Conclusions and Future Directions: While hearing aid intervention does not change the individual’s underlying processing abilities, understanding the extent of residual disability illuminates avenues for targeted rehabilitation beyond a hearing aid. The current data imply a need for a prospective clinical trial of hearing aid intervention including multiple auditory processing abilities and other non-auditory factors. Targeted auditory training or other novel rehabilitative approaches for hearing loss management could also be pursued as a result of this research.