Effectiveness of signal processing strategies for the pediatric population: a systematic review of the evidence

A systematic review of literature addressing the question "Is there evidence pointing to optimal signal processing for pediatric hearing aid patients?" was conducted. Key words and authors were used as search terms in five databases, and one textbook appendix was reviewed for related references. The levels of evidence that were accepted comprised randomized controlled trials, nonrandomized controlled trials, cohort, and before/after designs with or without control groups. Two hundred twenty-six articles were identified during the preliminary search with 183 of these eliminated by review of abstracts because they did not meet the search criteria. Forty-three manuscripts were reviewed, with eight meeting the evidence levels and search criteria. The strengths and weaknesses of these studies are highlighted, and the systematic review question is answered in light of these studies. There is evidence to recommend wide dynamic range compression signal processing for pediatric hearing aid users with mild, moderate, and moderately severe sensorineural hearing loss when full-time and consistent audibility is the goal of the hearing aid fitting. Further, there is evidence that audibility across a wide frequency bandwidth as well as across a large range of input levels is essential for pediatric hearing aid users to recognize critical components of the spoken language.