According to the Hearing Loss Association of America, hearing loss affects 48 million Americans today. If current trends continue, the number of individuals with age-related hearing loss worldwide will swell to 580 million by 2050. Also by 2050, the number of adults with dementia is expected to grow to 131.5 million worldwide, a substantial public health challenge.
A number of studies have demonstrated a connection between hearing loss and cognitive decline. Now, investigators at Brigham and Women’s Hospital are adding to a growing body of evidence that hearing loss is associated with a higher risk of cognitive decline. Findings from this study suggest that hearing loss may help identify individuals at greater risk of cognitive decline, and could provide insights for earlier intervention and prevention.
The researchers at Brigham and Women’s conducted an eight-year longitudinal study among 10,107 men aged >62 years in the Health Professionals Follow-up Study (HFPS). They assessed subjective cognitive function (SCF) scores based on responses to a six-item questionnaire administered in 2008, 2012 and 2016. SCF decline was defined as a new report of at least one SCF concern during follow-up.
The team found that hearing loss was associated with higher risk of subjective cognitive decline. Compared with men with no hearing loss, the relative risk of cognitive decline was:
- 30 percent higher among men with mild hearing loss
- 42 percent higher among men with moderate hearing loss
- 54 percent higher among men with severe hearing loss but who did not use hearing aids
Can Hearing Aids Help?
Researchers wanted to see if hearing aids might modify risk. Although they found that among men with severe hearing loss who used hearing aids, the risk of cognitive decline was somewhat less, it was not statistically significantly different from the risk among those who did not use hearing aids. The researchers noted that this may have been due to limited power or could suggest that if a difference truly exists, the magnitude of the effect may be modest. They also noted other limitations of the study, including the fact that this focused on predominantly older white male health professionals.
In the future, the team plans to investigate the relationships between self-reported hearing loss, change in audiometric hearing thresholds, and changes in cognition in women using several different assessment measures.
Meanwhile, a study conducted by the University of Exeter and King’s College London and was presented recently at the Alzheimer’s Association International Conference in Los Angeles, Calif.
The findings provide early evidence that wearing an effective hearing aid may help to protect the brain and reduce the risk of dementia.
In the PROTECT online study, 25,000 people aged 50 or over were divided into two groups, one which wore hearing aids and one which did not. They undertook annual cognitive tests over two years. At the conclusion of the study, the group who wore hearing aids performed better in measures assessing working memory and aspects of attention than those who did not wear hearing aids. On one attention measure, people who wore hearing aids showed faster reaction times.
The researchers said, “The PROTECT study is one of the largest studies to look at the impact of wearing a hearing aid, and suggests that wearing a hearing aid could actually protect the brain. We now need more research and a clinical trial to test this and perhaps feed into policy to help keep people healthy in later life.”
While more study is needed to determine whether wearing hearing aids can reduce the risk of cognitive decline, we do know that wearing hearing aids improves quality of life in terms of communication and relationships, and reduces the risk of depression.