Congenitally Deaf Children Cannot Benefit from Implants

Initially, arguments against use of the implant in congenitally deaf children centered on the idea that individuals without prior exposure to speech and language could not make use of the information provided by the implant. Early in its development, the cochlear implant was seen primarily as an aid to speechread-ing, and there was little expectation that open-set speech recognition without visual cues was a realistic goal. Postlinguistically deafened adults with well-developed oral language were able to use a combination of speechreading and contextual information together with the auditory cues provided by the implant to improve communication abilities. Early results with prelinguis-tically deafened adults were not as promising, leading some researches to suggest that loss of hearing before speech and language acquisition was a significant deterrent to successful cochlear implant use, possibly due to lasting effects of auditory deprivation.1

Studies such as those conducted by Shepherd et al.,8 Matsushima et al.,9 Lousteau,10 and Hartshorn et al.11 have provided evidence that suggests otherwise. Animal studies have shown that even in the presence of the auditory deprivation caused by congenital deafness, some cochleotopic organization remains and that electrical stimulation may both prevent degenerative changes in the neural pathways and may in fact produce morphologic and physiologic changes that improve function. Obviously, the longer the period of deprivation, the greater the negative impact; the positive benefit of the implant decreases. This has implications when considering implantation of older congenitally deaf children and adolescents who have not been consistent users of amplification.

What at first appeared to be decreased ability to benefit from an implant has generally come to be recognized as a developmental issue. Instead of comparing the information provided by a cochlear implant to an existing store of auditory language as in the case of a postlinguistically deafened user, the congenitally deaf implant recipient must use the information to develop language, as would any infant. The normally hearing infant spends the first year of life listening and receiving language before beginning to use it expressively. Therefore, the time course of 1 to 2 years required to see substantial results with congenitally deaf implant users12 is developmental^ appropriate.

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