Abstract:
While cochlear implants have helped hundreds of thousands of individuals, it remains difficult to predict the extent to which
an individual’s hearing will benefit from implantation. Several publications indicate that machine learning may improve predictive accuracy of cochlear implant outcomes compared to classical statistical methods. However, existing studies are limited in
terms of model validation and evaluating factors like sample size on predictive performance. We conduct a thorough examination of machine learning approaches to predict word recognition scores (WRS) measured approximately 12 months after
implantation in adults with post-lingual hearing loss. This is the largest retrospective study of cochlear implant outcomes to
date, evaluating 2,489 cochlear implant recipients from three clinics. We demonstrate that while machine learning models
significantly outperform linear models in prediction of WRS, their overall accuracy remains limited (mean absolute error:
17.9-21.8). The models are robust across clinical cohorts, with predictive error increasing by at most 16% when evaluated
on a clinic excluded from the training set. We show that predictive improvement is unlikely to be improved by increasing
sample size alone, with doubling of sample size estimated to only increasing performance by 3% on the combined dataset.
Finally, we demonstrate how the current models could support clinical decision making, highlighting that subsets of individuals
can be identified that have a 94% chance of improving WRS by at least 10% points after implantation, which is likely to be
clinically meaningful. We discuss several implications of this analysis, focusing on the need to improve and standardize data
collection.
