Just like a trusty pair of glasses can bring blurry vision into focus, hearing aids have the potential to improve cognitive function in middle-aged and older adults with hearing loss. A systematic review and meta-analysis of 15 studies revealed that for subjects without dementia, hearing aids led to improvements in global cognition, executive function, and episodic memory. Similarly, individuals with depressive symptoms saw enhancements in immediate memory, global cognition, and executive function. However, no significant improvement was found in individuals with Alzheimer’s disease or dementia. The meta-analysis also indicated that hearing aids had no significant effect on language or general executive function in subjects without dementia, as well as on specific areas such as executive function and processing speed in sub-group analysis. While the effects of hearing aids on cognitive function remained unclear for individuals with depressive symptoms, this research highlights their potential benefits for those without dementia. To further investigate the impacts of hearing aids, long-term randomized controlled trials and large-scale comparison-group studies are needed. Excitingly, this evidence suggests that by improving auditory input, hearing aids have the power to sharpen cognitive abilities for those experiencing hearing loss.

ObjectiveThe study aimed to examine the effects of hearing aids on cognitive function in middle-aged and older adults with hearing loss.Data sources and study selectionPubMed, Cochrane Library, and Embase were searched for studies published before 30 March 2022. Randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSIs) were included in the search. Restriction was set on neither types, severity, or the time of onset of hearing impairment nor cognitive or psychiatric statuses.Data extraction and synthesisTwo independent reviewers extracted data and assessed the study quality of RCTs. Cognitive function outcomes were descriptively summarized and converted to standardized mean difference (SMD) in the meta-analysis. Meta-analysis was conducted in RCTs. Sub-group analyses were conducted by cognitive statuses, psychiatric disorders, and cognitive domains.ResultsA total of 15 studies met the inclusion criteria, including five RCTs (n = 339) and 10 NRSIs (n = 507). Groups were classified as subjects without dementia or with normal global cognition, subjects with AD or dementia, and subjects with depressive symptoms. For subjects without dementia, improvements were found in global cognition, executive function, and episodic memory. For subjects with depressive symptoms, improvements were found in immediate memory, global cognition, and executive function. No improvement was found in subjects with AD or dementia. In total, four RCTs were included in the meta-analysis. For subjects without dementia (SMD = 0.11, 95% confidence interval [CI]: −0.15–0.37) and those with AD, no significant effect was found (SMD = −0.19, 95% CI: −0.65–0.28). For subjects without dementia, no significant effect was found in language (SMD = 0.14, 95% CI: −0.30–0.59) or general executive function (SMD = −0.04, 95% CI: −0.46–0.38). Further sub-group analysis found no significant effect in executive function (SMD = −0.27, 95% CI: −0.72–0.18) or processing speed (SMD = −0.02, 95% CI: −0.49–0.44).ConclusionHearing aids might improve cognitive performance in domains such as executive function in subjects without dementia. The effects on subjects with depressive symptoms remained unclear. No improvement was found in subjects with AD or dementia. Long-term RCTs and well-matched comparison-group studies with large sample sizes are warranted.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022349057.

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