Influence of compression in DSL v5.0 fittings on loudness perception and speech recognition in hearing-impaired adults
Abstract
Research has indicated that the broad audible bandwidth available in current hearing aids is associated with increased loudness for high-level sounds, compared to older, limited hearing aid bandwidths (Van Eeckhoutte et al., 2020a). This thesis used increased compression ratios to investigate further the trade-off between loudness perception, speech intelligibility and sound quality, with adaptive and dual-path compression.
26 participants with mild to severe hearing loss were fitted bilaterally with Phonak Audéo P90-13T hearing aids to Desired Sensation Level method version 5.0 targets with varying compression ratios. The within-subject design included loudness scaling, consonant recognition, and sound quality ratings. Linear mixed models were used to analyze the data.
The results suggest that increasing the compression ratio reduced loudness without negatively affecting consonant recognition or sound quality. Differences between hearing loss groups indicate that the magnitude of increase to successfully reduce loudness perception depends on the degree of hearing loss.