Influence of cochlear reserve on the outcome of hearing rehabilitation with cochlear implantation in adult patients

Introduction Presence of cochlear reserve indicated by speech understanding is a prerequisite to cochlear implantation (CI). Patients with high-level sensorineural hearing loss and bad speech understanding often receive CI, and yet the postoperative speech understanding varies widely. To better understand this variation in outcome, we explored the predictive influence of cochlear reserve.

Method Retrospective study among adults who received unilateral CI (2012-2019) with severe to profound hearing loss contralaterally. Preoperative tone and speech- audiogram with high power hearing aid were matched with post-implantation speech audiogram.

Results 78 adults (46 females) received unilateral CI (mean age 63 years). The tone-audiogram (TA) at 1kHz with hearing aid and pre-CI speech-audiogram (SA) at 65dB were plotted across each other and 3 groups were formed: Group A with 58 patients who had bad tone hearing and bad speech understanding (>60dB (TA) and =50 %  (SA)); Group B with 7 patients with bad tone hearing and relatively good speech understanding (> 60dB and >50 % ); and Group C with 13 patients with good tone hearing and bad speech understanding (=60dB and =50 % ). The post-CI mean speech understanding in group A was 49 ± 3 % , group B was 71 ± 2 %  and group C with 35 ± 3 %  at 65dB. Patients with bad tone hearing and good speech understanding (group B) had statistically significantly higher post-CI speech understanding than group C which had better tone hearing but worse speech understanding before CI (p=0.01).

ConclusionCochlear reserve plays an important role in the success of hearing rehabilitation. Patients with good tone hearing and bad speech comprehension seem to have poorer outcomes after CI. It is possible that auditory deprivation leads to spiral ganglion cell loss.

Poster-PDF A-1717.pdf

Publication History

Article published online:
13 May 2021