Language Development in Cochlear Implant Children

A cochlear implant is a device that stimulates the auditory nerve electrically to produce hearing percepts. It has an external component that receives incoming sound, processes it according to a predefined strategy, and transfers the signal across the skin. A small, implanted electronic device receives and decodes the transmitted signal and stimulates electrodes in the cochlea. The electrodes stimulate the auditory nerve directly, bypassing the hair cells that implement the first stage of auditory neural processing in normal ears. The extended use of multichannel cochlear implants in adults brought about the first major success, both scientific and commercial, of a neural sensory prosthesis that replaced a human sense with an electronic device Cochlear implants are now widely used in young deaf children and have shown tremendous promise in facilitating a variety of developmental outcomes. Specifically, improvements have been shown in oral language, speech perception and recognition, attention, and behavioral development.

Medical advances, as well as technological inventions such as digital hearing aids and cochlear implants, have made significant changes in the likelihood that a child with hearing loss will achieve adequate speech perception, intelligible speech and language competency, though none of these is yet guaranteed for all children . Despite these advances, it is probable that a child with hearing loss faces a significant delay in exposure to auditory stimulation, leading to delays in the normal course of oral language development through audition. Research findings suggest that children who received an implant even before 12 months had a one year expressive language delay . Others found variable degrees of delay with children who received implants before age 2 of years.Others found that lowering the age of implantation does seem to improve the prospects of normal language acquisition but the evidence does not suggest that children with cochlear implants perform like hearing peers on average .

Most children who are born profoundly deaf or who become deaf before the age of 3 years fall significantly behind their normal-hearing peers in their mastery of the surrounding oral language in its written, read, spoken, and signed forms.

One of the most important factors shown to influence the development of communication abilities in pediatric cochlear implant recipients is age at time of implantation .

Children implanted by 12 months of age demonstrate better language development compared with children who receive their cochlear implant between 13 and 24 months. This supports the provision of a cochlear implant within the first year of life to enhance the likelihood that a child with severe-to-profound hearing impairment will commence elementary school with age-appropriate language skills. The implanted prior to 3 years had significantly faster rates of language development than later-implanted children.

Two additional demographic factors that influence communication development in children with cochlear implants are communication mode and residual hearing. Children with prelingual deafness who use oral communication generally achieve significantly higher levels of speech perception, speech production, and/or language skills than their deaf peers who use total communication, that is, the combined use of signed and spoken language Speech perception performance with cochlear implants appears related to several factors. Higher speech perception appears linked to shorter periods of auditory deprivation, greater amounts of residual hearing, and younger ages of implantation Spoken language performance was related to the age the hearing loss was identified and the amount of typical hearing experience a child might have before losing their residual hearing