Systematic Review of Auditory Training Outcomes in Adult Cochlear Implant Recipients and Meta-Analysis of Outcomes

Objective: to review evidence on the efficacy of auditory training in adult cochlear implant recipients. Data Sources: PRISMA guidelines for a systematic review of the literature were followed. PubMed, Scopus, and CINAHL databases were queried on 29 June 2023 for terms involving cochlear implantation and auditory training. Studies were limited to the English language and adult patient populations. Study Selection: Three authors independently reviewed publications for inclusion in the review based on a priori inclusion and exclusion criteria. Inclusion criteria encompassed adult cochlear implant populations, an analysis of clinician- or patient-directed auditory training, and an analysis of one or more measures of speech recognition and/or patient-reported outcome. Exclusion criteria included studies with only pediatric implant populations, music or localization training in isolation, and single-sample case studies. Data Extraction: The data were collected regarding study design, patient population, auditory training modality, auditory training timing, speech outcomes, and data on the durability of outcomes. A quality assessment of the literature was performed using a quality metric adapted from the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group guidelines. Data Synthesis and Meta-Analysis: Data were qualitatively summarized for 23 studies. All but four studies demonstrated significant improvement in at least one measured or patient-reported outcome measure with training. For 11 studies with sufficient data reporting, pre-intervention and post-intervention pooled means of different outcome measures were compared for 132 patients using meta-analysis. Patient-direct training was associated with significant improvement in vowel-phoneme recognition and speech recognition in noise (p < 0.05 and p < 0.001, respectively), and clinician-directed training showed significant improvement in sentence recognition in noise (p < 0.001). Conclusions: The literature on auditory training for adult cochlear implant recipients is limited and heterogeneous, including a small number of studies with limited levels of evidence and external validity. However, the current evidence suggests that auditory training can improve speech recognition in adult cochlear implant recipients.