A systematic narrative synthesis of acute amplification-induced improvements in cognitive ability in hearing-impaired adults.

This systematic review investigated if hearing aid use was associated with acute improvements in cognitive function in hearing-impaired adults. The review question and inclusion/exclusion criteria were designed using the Population, Intervention, Control, Outcomes, and Study design (PICOS) mnemonic. The review was pre-registered in the International Prospective Register of Systematic Review (PROSPERO) and performed in accordance with the statement on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Thirteen articles, of various designs, published between 1990 and 2018, were identified a search of five electronic databases. Most studies reported 1-2 cognitive outcome measures. Nine studies reported a significant improvement in outcome and four studies reported no significant change. None of the 13 studies received a high score on a quality assessment checklist. Due to concerns over risk of bias and indirectness, the overall quality of evidence was graded as low. Only a few studies were identified, some of which report a small improvement in cognitive outcome; however, the overall quality of evidence was low. Further research is very likely to have an important impact on our confidence in answering the review question.