Auditory acclimatization in new adult hearing aid users : a registered systematic review of magnitude, key variables, and clinical relevance

Abstract

PURPOSE : Auditory acclimatization refers to changes in auditory performance over time due to hearing aid modifications, extending beyond task-specific or training effects. This preregistered systematic review expands on previous ones by examining a broader range of outcomes, including auditory (e.g., speech recognition, electrophysiological responses) and selected nonauditory (e.g., self-reported outcomes) measures. It aimed to assess acclimatization's presence, magnitude, and influencing factors, focusing on controlled trials comparing postfitting aided outcomes with a control group. This is the first review to comprehensively report self-reported outcomes, advancing the field. METHOD : A systematic literature search was conducted in CINAHL, PubMed, and Web of Science in March 2024. Eligible studies followed the Population, Intervention, Comparison, Outcome, Study Design, and Timeline framework, including new adult hearing aid users with sensorineural hearing loss using air-conduction hearing aids. Studies were required to report outcomes, with a comparator and at least two data points in the same condition. Exclusions applied to studies involving children, advanced feature devices, surgical implants, non–peer-reviewed work, or uncontrolled studies. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered on PROSPERO. A planned meta-analysis was excluded due to missing data. RESULTS : The review included 25 controlled studies on auditory acclimatization. Of these, 18 examined speech recognition, with 10 reporting acclimatization, one mixed, and seven no acclimatization. Among eight studies with self-reported outcomes, three supported acclimatization, three showed mixed results, and two found no evidence. For electrophysiological outcomes, four of seven studies reported acclimatization, and three did not. Consistent hearing aid use and hearing loss severity influenced acclimatization, while cognitive abilities and age had no significant impact. Of the 25 studies, 16% were rated good quality, 80% were rated fair, and 4% were rated poor, with common issues including lack of randomization, blinding, and insufficient sample size reporting. CONCLUSIONS : This review highlighted the complexity of auditory acclimatization, influenced by various factors. Evidence suggested acclimatization occurred in some users and outcomes, though improvements were modest and variable. The most consistent gains were in speech recognition in noise and self-reported measures (e.g., Abbreviated Profile of Hearing Aid Benefit, Hearing Handicap Inventory for the Elderly, Glasgow Hearing Aid Benefit Profile), though changes were generally modest. Future studies should include essential statistical data, prioritize randomized controlled trials, and ensure early baseline and key interval measurements to better isolate and quantify acclimatization effects.