Factors Affecting Speech Recognition Performance in Quiet and in Noise in Adults with Cochlear Implants

In the past decade, numerous papers have been published on variability in speech recognition in adults with a cochlear implant (CI). Many variables thought to influence the outcome of cochlear implantation have been investigated, both in retrospective and prospective studies. We investigated different biographic, audiologic and electrode position related variables for their relation with speech recognition performance in both quiet and in noise.

Participants were 129 adults with post-lingual onset of deafness, with Cochlear CI systems (either with a Contour Advanced or with a Slim Straight electrode) implanted at one CI center. Biographic factors were: age at implantation, level of education and psychological screening questionnaires. Audiologic factors were: duration of hearing loss, pre-implant residual hearing, pre-implantation speech recognition scores and post-implantation residual hearing loss. The electrode position was determined on high-resolution CT-scan post-implantation and analyses was made using “Matlab” software. Electrode position variables were: electrode scalar position, electrode insertion angle and wrapping factor (electrode proximity to the modiolus). CVC –wordlists were used to obtain phoneme scores at 55 dB and 70 dB to measure performance at three time-points post-implantation: three months, 12 months and at the time of post-implantation CT-scan. Speech recognition scores in noise were assessed using digits-in-noise (DIN) test at 12 or more months post-implantation.

To investigate the influence of biographic, audiologic and electrode position related variables of adult CI patients on speech perception performance in quiet and in noise, we used multivariate linear regression analysis. The results of variables explaining variability in speech understanding will be presented.