This study investigated three questions: Is it realistic to expect age-appropriate spoken language skills in children with cochlear implants (CIs) who received auditory-oral intervention during the preschool years? What characteristics predict successful spoken language development in this population? Are children with CIs more proficient in some areas of language than others? We analyzed language skills of 153 children with CIs as measured by standardized tests. These children (mean age 5 5 years and 10 months) attended programs in the United States (N 5 39) that used an auditory-oral educational approach. Age-appropriate scores were observed in 50% of the children on measures of receptive vocabulary, 58% on expressive vocabulary, 46% on verbal intelligence, 47% on receptive language, and 39% on expressive language. Regression analysis indicated that, after controlling for the effects of nonverbal intelligence and parent education level, children who received their implants at young ages had higher scores on all language tests than children who were older at implantation. On average, children with CIs performed better on certain language measures than others, indicating that some areas of language may be more difficult for these children to master than others. Implications for educators of deaf children with CIs are discussed.

The objective of this study was to document the development of speech, language, and reading skills between primary and secondary school ages in children who received cochlear implants during preschool years. Subjects were a sample of 85 North American adolescents recruited from a larger sample of 181 participants from a previous investigation. Students were first tested in early elementary school (ages eight to nine years) and were re-evaluated in high school (ages 15-18 years) for this study. The methods used were: performance on a battery of speech perception, language, and reading tests. These were compared at both test ages and significant predictors of outcome level identified through multiple regression analysis. Speech perception scores improved significantly with long-term cochlear implant use. Average language scores improved at a faster than normal rate, but reading scores did not quite keep pace with normal development. Performance in high school was most highly correlated with scores obtained in elementary grades. In addition, better outcomes were associated with lower PTA cochlear implant threshold, younger age at implantation and higher nonverbal IQ. In conclusion, early cochlear implantation had a long-term positive impact on auditory and verbal development, but did not result in age-appropriate reading levels in high school for the majority of students.

Growth curves indicate that children who are implanted by the age of 2 yr can achieve receptive vocabulary skills within the average range for hearing children.

Research studies reviewed here have identified a wide variety of factors that may influence a child's auditory, speech and language development following cochlear implantation. Intrinsic characteristics of the implanted child, including gender, family socio-economic status, age at onset of hearing loss and pre-implant residual hearing may predispose a child to greater or lesser post-implant benefit. Intervention characteristics that may influence outcome include age of the child when deafness is identified and amplification and habilitation is initiated, the communication mode used with the child and the type of classroom/therapy employed. Characteristics of the implant itself include generation of technology used, the age of the child when implant stimulation is initiated, and the amount of time the child has used the implant. These factors interact in unpredictable ways, so that isolated correlations between predictor variables and outcome scores may be difficult to interpret. Results for two independent samples of orally-educated children tested by different laboratories were compared using multiple regression analysis to illustrate interactions among predictor variables. Four predictor variables accounted for a similar proportion of variance (23% and 24%) in receptive vocabulary (PPVT) outcome scores in each sample. A unique predictor was then added to each analysis. The addition of pre-implant aided threshold not only increased the total variance accounted for to almost 40%, but also increased the effect of implant age as a predictor variable. A different result was observed in the other sample, were the added predictor variable was nonverbal IQ, where the estimated contribution of implant age was reduced. The current analysis suggests that future analyses minimally control for independent contributions of implant age, nonverbal IQ, and pre-implant aided thresholds when examining expected outcomes. Children in both samples who received a cochlear implant sometime between their first and second birthday achieved age-appropriate oral receptive vocabulary levels during preschool.

Use of sign to enhance spoken communication negatively influenced verbal rehearsal speed, which was a strong predictor of all early outcomes, which in turn strongly influenced later outcomes. These analyses suggest that early communication mode exerts a powerful influence on early outcomes that persist into later years. Speech perception, speech intelligibility, language, literacy, and psychosocial adjustment far exceeded that reported for similar groups before the advent of CI technology.