Systematic review of middle ear implants: do they improve hearing as much as conventional hearing AIDS?

OBJECTIVE: A systematic review to determine whether middle ear implants (MEIs) improve hearing as much as hearing aids. DATA SOURCES: Databases included MEDLINE, EMBASE, DARE, and Cochrane searched with no language restrictions from 1950 or the start date of each database. STUDY SELECTION: Initial search found 644 articles, of which 17 met the inclusion criteria of MEI in adults with a sensorineural hearing loss, where hearing outcomes and patient-reported outcome measures (PROMs) compared MEI with conventional hearing aids (CHAs). DATA EXTRACTION: Study quality assessment included whether ethical approval was gained, the study was prospective, eligibility criteria specified, a power calculation made and appropriate controls, outcome measures, and analysis performed. Middle ear implant outcome analysis included residual hearing, complications, and comparison to CHA in terms of functional gain, speech perception in quiet and in noise, and validated PROM questionnaires. DATA SYNTHESIS: Because of heterogeneity of outcome measures, comparisons were made by structured review.
CONCLUSION: The quality of studies was moderate to poor with short follow-up. The evidence supports the use of MEI because, overall, they do not decrease residual hearing, result in a functional gain in hearing comparable to CHA, and may improve perception of speech in noise and sound quality. We recommend the publication of long-term results comparing MEI with CHA, reporting a minimum of functional gain, speech perception in quiet and in noise, complications, and a validated PROM to guide the engineering of the new generation of MEI in the future.