Influences of listener gender and working memory capacity on speech recognition in noise for hearing aid users

Abstract

This study aimed to: (1) examine the influence of working memory capacity on the ability of experienced hearing aid users to recognize speech in noise using new noise reduction settings, and (2) investigate whether male and female hearing aid users differ in their hearing sensitivity and ability to recognize aided speech in noisy environments. 195 experienced hearing aid users (113 males and 82 females, age range: 33-80 years) from the n200 project were investigated. The Hagerman test (capturing speech recognition in noise) was administered using an experimental hearing aid with two digital signal processing settings: (1) linear amplification without noise reduction (NoP), and (2) linear amplification with noise reduction (NR). Gender differences were analysed using a series of independent samples from t-tests on Hagerman sentence scores, and the pure-tone average thresholds across the frequencies 500, 1000, 2000, and 4000 Hz (PTA4) for the left ear and right ear were measured. Working memory capacity (WMC) was measured using a reading span test. A WMC grouping (high and low) was included as a between-group subject factor in the within-group factors ANOVA, NR settings (Nop, NR), noise type (steady state noise, four-talker babble), and level of performance (50%, 80%). Male listeners had better pure-tone thresholds than female listeners at frequencies 500 and 1000 Hz, whereas female listeners had better pure-tone thresholds at 4000 Hz. Female listeners showed significantly better speech recognition ability than male listeners on the Hagerman test with NR , but not with NoP. This gender difference was more pronounced at the 80% performance level than at the 50% level. WMC had a significant effect on speech recognition ability, and there was a two-way interaction between WMC grouping and level of performance. The examination of simple main effects revealed superior performance of listeners with higher WMC at 80% using new NR settings. WMC, rather than background noise, was the main factor influencing performance at 80%, while at 50%, background noise was the main factor. WMC was associated with speech recognition performance even after accounting for hearing sensitivity (PTA4). This is the first study to demonstrate that experienced male and female hearing aid users differ significantly in their hearing ability and sensitivity and ability to recognize aided speech in noise. Thus, the average female listener has a greater speech recognition ability than the average male listener when linear amplification with NR is applied, but not when NoP is activated. An average female listener hears a given sound with greater sensitivity compared with an average male listener at higher frequencies. WMC is an important factor in speech recognition in more challenging listening conditions (i.e., lower signal-noise ratio) for experienced hearing aid users using new NR settings. More investigation is needed for a better understanding of how gender affects the ability of listeners less experienced with hearing aids (such as younger and...