Monosyllable speech perception of Japanese hearing aid users with prelingual hearing loss: implications for surgical indication of cochlear implant.

Objective: The monosyllable speech perception ability after years of educational intervention was compared between prelingually deafened pediatric hearing aid users and their cochlear implant counterparts.

Design: An open-set monosyllabic speech perception test was conducted on all subjects. The test required subjects to indicate a corresponding Japanese character to that spoken by the examiner. Fifty-two subjects with prelingual hearing impairment (47 hearing aid users and 5 cochlear implant users) were examined.

Results: Hearing aid users with average pure-tone thresholds less than 90 dB HL demonstrated generally better monosyllable perception than 70%, which was equivalent or better performance than that of the cochlear implant group. Widely dispersed speech perception was observed within the 90-99 dB HL hearing-aid user group with most subjects demonstrating less than 50% speech perception. In the cluster of >100 dB HL, few cases demonstrated more than 50% in speech perception. The perception ability of the vowel part of each mora within the cochlear implant group was 100% and corresponding to that of hearing aid users with moderate and severe hearing loss.

Conclusion: Hearing ability among cochlear implant users can be comparable with that of hearing aid users with average unaided pure-tone thresholds of 90 dB HL, after monosyllabic speech perception testing was performed.