Lingua dei segni e impianto cocleare: un incontro possibile

Profound and severe deafness in infants negatively affects spoken language acquisition. To date, many clinicians suggest cochlear implant and an oral education, with the exclusion of sign languages, as intervention strategy, believing that sign language may slow down spoken language development. This study investigates the first steps of language development in one deaf child, with cochlear implant and born from hearing parents, who was early exposed to both Italian Sign Language and Spoken Italian. The development of lexical comprehension and production, the growth of vocabulary size in spoken Italian and the relations between Italian Sign Language and Spoken Italian, were studied from 2.5 to 4.5 years. Results showed that vocabulary size (in terms of number of words/signs produced, i.e. the conceptual vocabulary score) grew consistently with chronological age. Furthermore, the growth rate of vocabulary size in spoken Italian matched with the growth rate found in a cross-sectional sample of monolingual hearing peers. As to the relation between the two languages, three phases were observed : i) before the implant the child relied almost exclusively on sign language ; ii) from 5 to 10 months after the implant the child began to use spoken Italian, but words were always accompanied by the corresponding signs ; iii) from about 1 year and a half after the implant onwards the child used words without the support of signs, but continued to rely on sign language when he was unable to retrieve lexical labels in spoken Italian. These findings suggest that early acquisition of sign language may facilitate the construction of conceptual representations and effectively scaffold the development of spoken language also in deaf children with cochlear implant.