The effect of phoneme-based auditory training on speech intelligibility in hearing-aid users

Hearing loss commonly causes difficulties in understanding speech in the presence of background noise. The benefits of hearing-aids in terms of speech intelligibility in challenging listening scenarios remain limited. The present study investigated if phoneme-in-noise discrimination training improves phoneme identification and sentence intelligibility in noise in hearing-aid users. Two groups of participants received either a two-week training program or a control intervention. Three phoneme categories were trained: onset consonants (C1), vowels (V) and post-vowel consonants (C2) in C1-V-C2-/i/ logatomes from the Danish nonsense word corpus (DANOK). Phoneme identification test and hearing in noise test (HINT) were administered before and after the respective interventions and, for the training group only, after three months. Twenty 63-to-79 years old individuals with a mild-to-moderate sensorineural hearing loss and at least one year of experience using hearing-aids. The training provided an improvement in phoneme identification scores for vowels and post-vowel consonants, which was retained over three months. No significant performance improvement in HINT was found. The study demonstrates that the training induced a robust refinement of auditory perception at a phoneme level but provides no evidence for the generalisation to an untrained sentence intelligibility task.