Individual Variability of Hearing-Impaired Consonant Perception

The study of hearing impaired speech recognition at the consonant level allows for a detailed examination of individual variability. Use of low-context stimuli, such as consonants, aids in minimizing the influence of some variable cognitive abilities (e.g., use of context, memory) across listeners and focuses on differences in the processing or interpretation of the existing acoustic consonant cues. We show that hearing-impaired perception can vary across multiple tokens of the same consonant, in both noise robustness and confusion groups. Withinconsonant differences in noise robustness are related to differences in intensity of the consonant cue region. For a single listener, high errors can exist for a small subset of test stimuli, and performance for the majority of test stimuli can remain at ceiling. The existence of withinconsonant differences in confusion groups entails that an average over multiple tokens of the same consonant results in a larger confusion group than for a single consonant token. For each consonant token, the same confusion group is consistently observed across a population of hearing impaired listeners. Quantifying perceptual differences provides insight into the perception of speech under noisy conditions and characterizes each listener’s hearing impairment.