Background: The outcome of cochlear implantation has improved over the last decades, but there are still patients with less benefit. Despite numerous studies examining the cochlear implant (CI) outcome, variations in speech comprehension with CI remains incompletely explained. The aim of this study was therefore to examine preoperative pure-tone audiogram and speech comprehension as well as aetiology, to investigate their relationship with postoperative speech comprehension in CI recipients.
Methods: A retrospective study with 664 ears of 530 adult patients was conducted. Correlations between the target variable postoperative word comprehension with the preoperative speech and sound comprehension as well as aetiology were investigated. Significant correlations were inserted into multivariate models. Speech comprehension measured as word recognition score at 70 dB with CI was analyzed as (i) a continuous and (ii) a dichotomous variable.
Results: All variables that tested preoperative hearing were significantly correlated with the dichotomous target; with the continuous target, all except word comprehension at 65 dB with hearing aid. The strongest correlation with postoperative speech comprehension was seen for monosyllabic words with hearing aid at 80 dB. The preoperative maximum word comprehension was reached or surpassed by 97.3% of CI patients. Meningitis and congenital diseases were strongly negatively associated with postoperative word comprehension. The multivariate model was able to explain 40% of postoperative variability.
Conclusion: Speech comprehension with hearing aid at 80 dB can be used as a supplementary preoperative indicator of CI-aided speech comprehension and should be measured regularly in the clinical routine. Combining audiological and aetiological variables provides more insights into the variability of the CI outcome, allowing for better patient counselling.
Keywords: auditory rehabilitation; cochlear implant; hearing loss; prediction model; preoperative audiometric diagnostics; speech comprehension; speech perception.