Objective: A systematic review of literature to determine the clinical outcome and safety of the range of acoustic hearing implants (AHIs) in adults with mixed hearing loss (MHL).
Data sources: Databases MEDLINE, Embase, and Cochrane were searched with no language restrictions between 1950, or the start date of each database, up to March 1, 2013.
Study selection: Initial search found 1,794 studies, of which, 19 met the inclusion criteria of AHI for adults with MHL where safety, coupling strategies to the inner ear, hearing outcome, and patient-reported outcome measures (PROMs) were analyzed, preferably compared with a conventional hearing aid or a bone-conduction implant.
Data extraction: A study quality assessment based on different parameters was included: specification of eligibility criteria, prospective study, ethical approval gained, appropriate controls, power calculation, outcome measures, and analysis performed.
Data synthesis: Comparisons between studies were made based on structured review as meta-analysis was not feasible because of the heterogeneity of outcome measures and reports.
Conclusion: The current systematic review shows that AHI and their different coupling strategies in the treatment of MHL were beneficial in terms of speech in quiet, PROM, and safety regarding residual hearing. Overall, the level of evidence and the quality of the included studies were judged to be moderate to low. More comprehensive data on coupling to the inner ear and the comparison with conventional hearing aids or alternatives for speech in noise is mandatory. Long-term follow-up data are also needed.