[Cochlear implant management of young children]

Since 1988, more than 450 children have received cochlear implants at the Department of Otolaryngology of the Medizinische Hochschule Hannover. Among them are 38 children who underwent surgery before the age of two. Due to increasing experience with this technique, the mean age at implantation has decreased over time so that most children nowadays receive implants between the ages of two and five. In terms of the critical periods of both development of the auditory system and the acquisition of language, it is advantageous for even younger children to receive implants soon after detection of deafness. However, the present diagnostic tools do not allow proper estimation of residual hearing and additional handicaps. Therefore longer periods of hearing aid use and audioverbal training are mandatory before implantation. Additional objections against early implantation are biosafety problems such as head growth, the high incidence of otitis media, and the specific surgical anatomy. This paper outlines criteria for patient selection, the surgical concept, postoperative rehabilitation, and complications.

Twenty-six children suffered from postmeningitic deafness and beginning obliteration of the cochlea as shown by repeated high resolution CT scans. Nine children had congenital deafness which was detected early in life and showed no improvement after proper hearing aid fitting and audioverbal training for speech development. Three children had severe inner ear malformations detected by CT scans. All children had no ABR or CAP responses in ECoG. Their developmental, language, and neuropaediatric status was examined.

Thirty-five children received the Nucleus Mini 22 cochlear implant; three children received the Clarion 1.2 device. The surgery was not different from adult surgery. Special care was given to proper fixation and placement of the electrode in the drilled out mastoid to compensate for head growth. POSTOPERATIVE RESULTS: All children wear the speech processor regularly. They are able to detect everyday sounds and suprasegmental features of speech after a few months. After one year, the child begins to understand and produce speech; after two years speech understanding has been achieved and normal language development starts with small sentences. The complication rate was not higher than in other age groups of patients. Fitting and tune-up of the speech processor required a broad range of experience and a specialized team working at the children's implant center.

Early implantation in children is both possible and effective in selected cases. Due to an improved early detection of deafness, it should be possible to increase the percentage of children with early cochlear implantation.