Relationships among speech perception, production, language, hearing loss,and age in children with impaired hearing

Eighty-seven primary-school children with impaired hearing were evaluated u sing speech perception, production, and language measures over a 3-year per iod. Forty-seven children with a mean unaided pyre-tone-overage hearing los s of 106 dB HL used a 22-electrode cochlear implant, and 40 with a mean una ided puretone-average hearing loss of 78 dB HL were fitted with hearing aid s. All children were enrolled in oral/aural habilitation programs, and most attended integrated classes with normally hearing children for part of the time at school. Multiple linear regression was used to describe the relati onships among the speech perception, production, and language measures, and the trends over time. little difference in the level of performance and tr ends was found for the two groups of children, so the perceptual effect of the implant is equivalent, on average, to an improvement of about 28 dB in hearing thresholds. Scores on the Peabody Picture Vocabulary Test (PPVT) an d the Clinical Evaluation of language Fundamentals showed an upward trend a t about 60% of the rate for normally hearing children. Rates of improvement for individual children were not correlated significantly with degree of h earing loss. The children showed a wide scatter about the average speech pr oduction score of 40% of words correctly produced in spontaneous conversati ons, with no significant upward trend with age. Scores on the open-set Cons onant-Nucleus-Consonant (CNC) monosyllabic word test and the Bench-Kowal-Ba mford (BKB) sentence test were strongly related to language level (as measu red by an equivalent age on the PPVT) and speech production scores for both auditory-visual and auditory test conditions. After allowing for differenc es in language, speech perception scores in the auditory test condition sho wed a slight downward trend over rime, which is consistent with the known b iological effects of hearing loss on the auditory periphery and brainstem. Speech perception scores in the auditory condition also decreased significa ntly by about 5% for every 10 de of bearing loss in the hearing aid group T he regression analysis model allows separation of the effects of language, speech production, and hearing levels on speech perception scores so predic ted. The model suggests that most of the children in the study will reach a level of over 90% sentence recognition in the auditory-visual condition wh en their language becomes equivalent to that of a normally hearing 7-year-o ld, but they will enter secondary school at age 12 with an average language delay of about 4 or 5 years unless they receive concentrated and effective language training.