Hearing loss and dementia – who is listening?

Hearing loss and dementia are both common among older people. The question is: Does hearing loss cause dementia?

The co-occurrence of the two conditions has increased researchers’ interest in the relationship between dementia and hearing loss in recent years. A growing body of evidence suggests that hearing loss may be a significant risk factor for Alzheimer’s disease and other forms of dementia, according to the New York Times Magazine. Even though emerging research reveals a potential link between hearing loss and dementia, experts don’t know if the hearing loss leads to dementia.

The 2017 Lancet Commission report shows that hearing loss is the largest modifiable risk factor against dementia. Yet, can hearing loss cause dementia?

Researchers first studied the possible connection between hearing loss and dementia on a large scale in 2011. Dr. Frank Lin, at the Johns Hopkins School of Medicine, published the results of the study in JAMA Neurology. The study tested the hearing of 639 older adults with a hearing loss but dementia-free and tracked them for 12 years. The study found that 58 older adults developed Alzheimer’s or another cognitive impairment. The researchers also noted that a chance of developing dementia increased in direct proportion to the severity of hearing loss.

A new study led by Sharon Curhan, a physician at Brigham and Women’s hospital, confirms Dr. Lin’s findings. The results of the eight-year study were published in the Journal of Nutrition in 2019. The conclusions reveal that hearing loss is associated with a higher risk of subjective cognitive decline, which is one of the earliest noticeable symptoms of Alzheimer’s disease and related dementia. The results suggest that hearing loss may help identify individuals at greater risk of dementia and provide insights for earlier intervention and prevention.

Fortunately, new insights point to a far more important role of hearing aids. Researchers recently found that wearing hearing aids may delay cognitive decline in older adults and even improve brain function.

A study led by Elham Mahmoudi, Ph.D., at the University of Michigan showed that wearing hearing aids could delay cognitive decline in older adults. The findings, published in the Journal of the American Geriatrics Society in 2019, indicated that older adults with hearing loss who did wear a hearing aid were 18% at less risk of being diagnosed with dementia, including Alzheimer’s disease.

The results of a French study, published in the Journal JAMA Otolaryngology-Head Neck Surgery, add to mounting evidence that links the use of hearing aids and the early onset of dementia in people with hearing loss. The study examined data on cochlear implants, memory, and mental flexibility in elderly individuals aged 65 to 85 with profound hearing loss. The team of researchers led by Dr. Isabelle Mosnier of Assistance Publique-Hopitaux de Paris credited the improvements in cognition to the cochlear implants in the elderly. They found that more than 80% of those with the lowest cognitive scores showed significant improvement one year after implantation.

Unfortunately, hearing loss prevalence will likely grow as the population age. Millions of Americans who suffer hearing loss might be at greater risk for cognitive decline and dementia. Therefore, the key to reducing that risk is regular hearing tests to diagnose and treat the hearing loss before it can have an impact on brain health.

If you suspect that you have a hearing loss and would like to treat it, the best place to start is with a trusted audiologist near you.