Development of spoken language grammar following cochlear implantation in prelingually deaf children.

OBJECTIVES To assess the development of grammar comprehension in spoken language in prelingually deaf children following cochlear implantation and compare their grammatical abilities with those of their hearing peers. DESIGN A prospective study of 82 consecutive prelingually deaf children up to 5 years following implantation. The children were less than 7 years old at the time of implantation (mean age +/- SD, 4.2 +/- 1.3 years). All received the same multichannel cochlear implant system. No child was lost to follow-up and there were no exclusions from the study. SETTING Tertiary referral cochlear implant center. METHODS The children were assessed using the Test for Reception of Grammar. This individually administered, multiple-choice test designed to assess the understanding of grammatical contrasts in the English language also allows direct comparison of grammar comprehension between test subjects and their normal-hearing peers. RESULTS Before implantation, only a small proportion (2%) of prelingually deaf children were above the first percentile of their normal-hearing peers. This percentage increased to 40% and 67%, respectively, 3 and 5 years after implantation; and 5 years after implantation, 20% of the children performed between the 25th and the 75th percentile or better. In the subgroup of children who received their cochlear device before the age of 4 years, this percentage reached 36%. CONCLUSIONS Spoken language grammar acquisition in prelingually deaf children with a cochlear implant was found to be considerably delayed. However, there was a clear trend toward the development of grammar skills following cochlear implantation, and the greatest advance was made by children who received their implant at a younger age. These findings support the present trend toward early implantation.