Do hearing aids improve cognition in the elderly?
The main reasons to use hearing aids are to improve hearing, communication, and quality of life. Overall, in this study, hearing aids had no effect on cognition except in a highly select subgroup of elders who were already participating in a longitudinal cohort study of cardiovascular health.
Randomized controlled trial (nonblinded)
These researchers recruited participants from 2 different groups. The first was a group of elders from the Atherosclerosis Risk in Communities (ARIC) study, a long-standing cohort study of cardiovascular health. The participants in this study were 45 to 64 years of age at the time of initial recruitment (1987–1989) who had already had several serial assessments, including neurocognitive testing. The second group came from de novo community volunteers. To be included, the participants had to be 70 to 84 years of age, have adult-onset hearing loss (pure tone average between 30 and 70 decibels), and have no significant cognitive deficit. The researchers randomized patients (allocation masking uncertain) to receive custom hearing aids (n = 490) or health education (n = 487). The proportion of those who were eligible (and subsequently randomized) increased by 5% in the ARIC group and decreased by 5% in the de novo group suggesting potential participation bias in the ARIC cohort. Each group, respectively, met in person (or virtually during the pandemic) with an audiologist or health educator for several sessions. Overall, the 2 intervention groups were comparable at baseline, but the ARIC participants were older, more likely to be female, more likely to be Black, have lower levels of education and income, have diabetes, have hypertension, live alone; and have slightly lower Mini-Mental State Examination scores than the de novo participants. At the end of 3 years, only lost 10% of the participants were lost to follow-up. Overall, there was no difference in global cognitive change between the 2 interventions. However, when the researchers looked only at the participants from ARIC, after adjusting for multiple factors, those who received hearing aids had statistically significant improvements in global cognitive and language function. It is unclear if these differences were clinically meaningful. The authors conclude that the improvement in the ARIC group can be partially explained by it being a higher risk group because of cardiovascular risk factors, but it is at least as likely that the improvement can be explained by participation bias. Since the authors did not directly assess underlying cardiovascular risk factors in their analysis, their conclusion is purely supposition.
Henry C. Barry, MD, MS
Michigan State University
East Lansing, MI