Results of cochlear implantation in patients with severe to profound hearing loss - Implications for patient selection

In patients with some residual hearing and minor benefit from conventional hearing aids, the benefits of cochlear implantation have to be weighed care fully against eventual adverse effects. In this study, pre- and post-operat ive thresholds as well as functional results after cochlear implantation ar e reported; 17 of 44 implanted adults had residual hearing pre-operatively (mean threshold((250 to 4000 Hz)): 106 dB HL) in the implanted ear. Residua l hearing in the implanted ear could not? in general, be preserved post-ope ratively. Seventeen of 44 implanted children had some amount of residual hearing in t he implanted ear pre-operatively (implanted ear: 114 dB HL; contralateral e ar: 109.9 dB HL; mean thresholds((250 to 4000 Hz)))). Contrary to the results in adults, residual hearing in the implanted ear re mained statistically unchanged. Hearing in the contralateral ear increased significantly from 109.9 to 101.9 dB HL post-operatively. This increase was mainly attributed to maturation of the central auditory pathway. In adults with residual hearing, the monosyllable word recognition scores increased significantly from 9 per sent preoperatively to 42 per cent post-operativel y. Children with residual hearing tended to perform better on speech-relate d test material compared to children without prior auditory experience. Coc hlear implantation is indicated in adults and children with residual hearin g and minor benefit from conventional amplification. The contralateral ear in children should be considered for additional acoustical stimulation.