A surgeon-scientist's perspective and review of cognitive-linguistic contributions to adult cochlear implant outcomes

Abstract

Objective(s): Enormous variability in speech recognition outcomes persists in adults who receive cochlear implants (CIs), which leads to a barrier to progress in predicting outcomes before surgery, explaining “poor” outcomes, and determining how to provide tailored rehabilitation therapy for individual CI users. The primary goal of my research program over the past 9 years has been to extend our understanding of the contributions of “top-down” cognitive-linguistic skills to CI outcomes in adults, acknowledging that “bottom-up” sensory processes also contribute substantially. The main objective of this invited narrative review is to provide an overview of this work. A secondary objective is to provide career “guidance points” to budding surgeon-scientists in Otolaryngology. Methods: A narrative, chronological review covers work done by our group to explore top-down and bottom-up processing in adult CI outcomes. A set of ten guidance points is also provided to assist junior Otolaryngology surgeon-scientists. Results: Work in our lab has identified substantial contributions of cognitive skills (working memory, inhibition-concentration, speed of lexical access, nonverbal reasoning, verbal learning and memory) as well as linguistic abilities (acoustic cue-weighting, phonological sensitivity) to speech recognition outcomes in adults with CIs. These top-down skills interact with the quality of the bottom-up input. Conclusion: Although progress has been made in understanding speech recognition variability in adult CI users, future work is needed to predict CI outcomes before surgery, to identify particular patients' strengths and weaknesses, and to tailor rehabilitation approaches for individual CI users. Level of Evidence: 4.