ABSTRACT
OBJECTIVE: This study characterised the relationship between speech intelligibility and quality in listeners with hearing loss for a range of hearing-aid processing settings and acoustic conditions. DESIGN: Binaural speech intelligibility scores and quality ratings were measured for sentences presented in babble noise and processed through a hearing-aid simulation. The intelligibility-quality relationship was investigated by (1) assessing the effects of experimental conditions on each task; (2) directly comparing intelligibility scores and quality ratings for each participant across the range of conditions; and (3) comparing the association between signal envelope fidelity (represented by a cepstral correlation metric) and intelligibility and quality. STUDY SAMPLE: Participants were 15 adults (7 females; age range 59-81 years) with mild to moderately severe sensorineural hearing loss. RESULTS: Intelligibility and quality showed a positive association both with each other and with changes to signal fidelity introduced by the entire acoustic and signal-processing system including the additive noise and the hearing-aid output. As signal fidelity decreased, quality ratings changed at a slower rate than intelligibility scores. Individual psychometric functions were more variable for quality compared to intelligibility. CONCLUSIONS: Variability in the intelligibility-quality relationship reinforces the importance of measuring both intelligibility and quality in clinical hearing-aid fittings.
Subject(s)
Deafness , Hearing Aids , Hearing Loss, Sensorineural , Hearing Loss , Speech Perception , Aged , Aged, 80 and over , Female , Hearing , Hearing Loss, Sensorineural/diagnosis , Humans , Male , Middle Aged , Speech IntelligibilityABSTRACT
Purpose The overall goal of the current study was to determine whether noise type plays a role in perceptual quality ratings. We compared quality ratings using various noise types and signal-to-noise ratio (SNR) ranges using hearing aid simulations to consider the effects of hearing aid processing features. Method Ten older adults with bilateral mild to moderately severe sensorineural hearing loss rated the sound quality of sentences processed through a hearing aid simulation and presented in the presence of five different noise types (six-talker babble, three-talker conversation, street traffic, kitchen, and fast-food restaurant) at four SNRs (3, 8, 12, and 20 dB). Results Everyday noise types differentially affected sound quality ratings even when presented at the same SNR: Kitchen and three-talker noises were rated significantly higher than restaurant, traffic, and multitalker babble, which were not different from each other. The effects of noise type were most pronounced at poorer SNRs. Conclusions The findings of this study showed that noise types differentially affected sound quality ratings. The differences we observed were consistent with the acoustic characteristics of the noise types. Noise types having lower envelope fluctuations yielded lower quality ratings than noise types characterized by sporadic high-intensity events at the same SNR.
