COCHLEAR IMPLANTATION IN VERY YOUNG-CHILD REN

Introduction: Since 1988, more than 450 children have received cochlea r implants at the Department of Otolaryngology of the Medizinische Hoc hschule Hannover. Among them are 38 children who underwent surgery bef ore the age of two. Due to increasing experience with this technique, the mean age at implantation has decreased over time so that most chil dren nowadays receive implants between the ages of two and five. In te rms 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 resid ual hearing and additional handicaps. Therefore longer periods of hear ing aid use and audioverbal training are mandatory before implantation . Additional objections against early implantation are biosafety probl ems such as head growth, the high incidence of otitis media, and the s pecific surgical anatomy. This paper outlines criteria for patient sel ection, the surgical concept, postoperative rehabilitation, and compli cations. Patients: Twenty-six children suffered from postmeningitic de afness 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 hear ing 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, la nguage, and neuropaediatric status was examined. Surgery: Thirty-five children received the Nucleus Mini 22 cochlear implant; three children received the Clarion 1.2 device. The surgery was not different from a dult surgery. Special care was given to proper fixation and placement of the electrode in the drilled out mastoid to compensate for head gro wth. Postoperative results: All children wear the speech processor reg ularly. They are able to detect everyday sounds and suprasegmental fea tures of speech after a few months. After one year, the child begins t o understand and produce speech; after two years speech understanding has been achieved and normal language development starts with small se ntences. The complication rate was not higher than in other age groups of patients. Fitting and tune-up of the speech processor required a b road range of experience and a specialized team working at the childre n's implant center. Conclusion: Early implantation in children is both possible and effective in selected cases. Due to an improved early de tection of deafness, it should be possible to increase the percentage of children with early cochlear implantation.