[Cochlear implant for non-deaf patients?].

BACKGROUND

Cochlear implants have proven to be the method of choice for postlingually deafened adults. The great success of this application requires discussion of the degree in which the indication for cochlear implantation should be expanded to include patients with residual hearing.

METHOD AND PATIENTS

Following an initial discussion of the term deafness, we present the preoperative and postoperative results in five patients with residual hearing. These patients achieve a certain degree of speech recognition with their well fitted hearing aids. However, their aided speech intelligibility did not exceed 30% with the standardized Freiburg monosyllabic word test at 70 dB. In each case the worse hearing ear was treated with a cochlear implant. Speech discrimination in silence and noise are compared with the results of a group of postlingually deafened cochlear implant patients.

RESULTS

The five patients are very satisfied with the cochlear implant and use the telephone to communicate with unknown partners. They score 100% in the standardized four-syllable number test above 55 dB and they document a loss of speech discrimination between 0 and 25% within the open-set monosyllabic word test. The mean increase of best monosyllable intelligibility by the cochlear implant over the hearing aids is 65%. Using the innsbruck sentence test the patients score 100% at 70 dB; with the Göttingen sentence test, the mean result is 75%. Their mean results in noise are also very good, 76% at 10 dBS/N and 57% at 5 dBS/N respectively. None of these patients use the hearing aid on the untreated, better hearing ear.

CONCLUSION

A multichannel cochlear implant lead to a significant improvement of speech comprehension in these patients with residual hearing. We can successfully implant patients with minimal benefit of their well fitted hearing aids. Our group is too small to be able to define general selection criteria. For the time being we use as an audiological indication a open-set monosyllabic word intelligibility of not more than 30% at 70 dB with well fitted hearing aids.