Auditory filter characteristics and consonant recognition for hearing-impaired listeners

TLDR

Previous work linked stop‑consonant recognition to the articulation index in normal‑hearing listeners. The study examined how frequency resolution relates to speech recognition by measuring auditory filter parameters and stop‑consonant recognition in normal‑hearing and hearing‑impaired listeners. Speech‑presentation levels were chosen based on AI predictions to span a wide range of recognition scores, and a strategy that equalizes audible spectra across listeners was used to compare performance despite varied hearing loss. Auditory filter widths and dynamic ranges correlated strongly with hearing thresholds, yet stop‑consonant recognition matched AI predictions and showed no link to filter characteristics, implying that any apparent association between frequency resolution and speech recognition is driven mainly by threshold elevation.

Abstract

To examine the association between frequency resolution and speech recognition, auditory filter parameters and stop-consonant recognition were determined for 9 normal-hearing and 24 hearing-impaired subjects. In an earlier investigation, the relationship between stop-consonant recognition and the articulation index (AI) had been established on normal-hearing listeners. Based on AI predictions, speech-presentation levels for each subject in this experiment were selected to obtain a wide range of recognition scores. This strategy provides a method of interpreting speech-recognition performance among listeners who vary in magnitude and configuration of hearing loss by assuming that conditions which yield equal audible spectra will result in equivalent performance. It was reasoned that an association between frequency resolution and consonant recognition may be more appropriately estimated if hearing-impaired listeners’ performance was measured under conditions that assured equivalent audibility of the speech stimuli. Derived auditory filter parameters indicated that filter widths and dynamic ranges were strongly associated with threshold. Stop-consonant recognition scores for most hearing-impaired listeners were not significantly poorer than predicted by the AI model. Furthermore, differences between observed recognition scores and those predicted by the AI were not associated with auditory filter characteristics, suggesting that frequency resolution and speech recognition may appear to be associated primarily because both are degraded by threshold elevation.