Cortical neuroplasticity in children after early cochlear implantation

Abstract

Hearing is crucial to learn and use language. Loss of hearing in children affects the development of speech, language and cognitive abilities, and severely impairs social capabilities. Thus, efforts to restore auditory perception are determinative and research should be focused on factors likely to bring about the best prognosis. Numerous experimental observations demonstrate that there is a sensitive or critical period for cochlear implantation. Implantations performed in prelingually deaf children in this period are associated with better results in terms of speech recognition and language acquisition. This is the time period in which brain plasticity shows its highest level of development. There is increasing interest in establishing the optimum age to implant congenitally deaf children so that the maximum potential of neuroplasticity is exploited. Different authors have established different limits; however, all of them agree that the best time is in the first years of life, between two and four years of age. Reasons based upon speech recognition, language acquisition, and experimental data such as electrophysiological recordings or metabolism of different areas in the brain, support these statements. Nevertheless, before making any recommendation about the suitability of early cochlear implantations, a complete analysis of benefits and disadvantages should be performed. Retrospective studies of very early implanted children have not shown a higher risk during anaesthesia or significant complexity of the surgical procedure. Moreover, advances in audiological diagnostic techniques make the confirmation of hearing loss more accurate and safer at lower ages. Due to this, it seems consistent to advise cochlear implantation before two years of age provided that there is confirmation of hearing loss and no additional issues increasing the risks of early implantation.

• Plasticity
• auditory
• sensitive period
• cochlear implant