Hearing loss is a prevalent condition among older adults, affecting nearly two-thirds of those over 70. Beyond diminished hearing, it can lead to loneliness, depression, and social isolation. New research indicates a link between hearing loss and a higher risk of cognitive decline and dementia. The 2024 Lancet Commission on Dementia Prevention, Intervention, and Care has identified hearing loss as one of 14 modifiable risk factors for dementia. According to the commission, addressing hearing loss could prevent up to 7% of dementia cases globally. This has led to questions about whether hearing aids can mitigate the increased dementia risk associated with hearing loss.
The ACHIEVE Study
The Aging and Cognitive Health Evaluation in Elders (ACHIEVE) study, a large multi-center randomized controlled trial, investigated whether treating hearing loss in older adults could slow cognitive decline. The study, published in the Lancet, enrolled 977 participants aged 70 to 84 with mild to moderate hearing loss and no substantial cognitive impairment. Participants were recruited from two sources: the Atherosclerosis Risk In Communities (ARIC) study and newly recruited community members. The study compared a hearing intervention to a health education control group over three years, measuring cognition annually.
Study Design and Interventions
The hearing intervention consisted of four sessions with an audiologist, including hearing aid fitting and education on communication strategies. The control group received health education based on the 10 keys to healthy aging, such as blood pressure monitoring and physical activity. While the main cohort did not show a significant effect of hearing intervention on cognitive decline, a pre-specified sensitivity analysis revealed notable differences within the subgroups.
Key Findings
In participants from the ARIC study, the hearing intervention led to a 48% reduction in the rate of cognitive decline compared to the control group. However, no significant difference was observed in the newly recruited participants. These differences may be attributed to variations in the rate of cognitive decline between the cohorts, with the ARIC participants experiencing a faster rate of decline. Additionally, practice effects from repeated cognitive testing in the ARIC cohort may have contributed to the observed differences.
Implications and Future Directions
Alison Huang, an epidemiologist and Senior Research Associate from the Johns Hopkins Cochlear Center for Hearing and Public Health, noted that the findings suggest that intervening on hearing loss in late life can still make a difference in cognitive outcomes. The ACHIEVE study also measured social and mental health, physical activity, and brain structure and function using MRI. Further analyses are underway to explore the broader impact of hearing intervention on health. Data from the ACHIEVE study will be made public by the end of the year, encouraging further research in this area.
Over-The-Counter Hearing Aids and Awareness
The Over-The-Counter Hearing Aid Act, passed in 2017, aims to increase accessibility and affordability by allowing hearing aids to be sold over the counter. This has opened the market to new companies and technologies, such as Apple's AirPod Pros, potentially reducing the stigma associated with hearing aids. The Cochlear Center is also promoting hearing awareness through the Hearing Number Campaign, encouraging individuals to test their hearing and track it as a health metric.
These efforts aim to normalize the conversation around hearing health and encourage early intervention to mitigate the potential cognitive impacts of hearing loss.
