Aim: the aim of this study was to compare spoken language production in children with permanent childhood hearing impairment (PCHI) whose PCHI was confirmed either early or late.
Method: audio-taped spoken narrative was assessed for syntax, phonology, morphology, and narrative in transcripts from a population-based sample of 89 children (49 males, 40 females; age mean age 7y 7mo, SD1y 1mo, range 6y 6mo-10y 9mo) with bilateral PCHI (≥ 40dB hearing loss) and a comparison group of 63 children (37 males, 26 females; mean age 8y 1mo; SD 1y) with normal hearing. Of the 89 children with PCHI, 41 (21 males, 20 females) had their hearing impairment confirmed by the age of 9 months. All children with PCHI were tested with hearing aids in place, including 16 with cochlear implants. The group of children whose PCHI had been confirmed by age 9 months was compared with the group with later confirmation of PCHI using regression models on the outcome measures.
Results: compared with those with late-confirmed PCHI, children with early-confirmed PCHI used significantly more sentences (mean difference 2.7; 95% confidence interval [CI] 0.49-5.24; p=0.019) and categories of high-pitched morphological markers (mean difference 6.64; 95% CI 1.96-11.31; p=0.006). The number of categories of low-pitched morphological markers, phonological simplifications, and sentences with multiple clauses did not differ between groups. The odds ratios (95% CI) of superior narrative structure and narrative content in children whose PCHI was confirmed early were 3.03 (1.09-8.46; p=0.034) and 4.43 (1.52-12.89; p=0.006) respectively.
Interpretation: early confirmation compared with late confirmation of PCHI was associated with benefit to narrative skills and to certain expressive aspects of syntax and morphology, but not expressive phonology.