Over the past few months, I noticed my husband inching the volume up on his phone or TV. Or I'd see him struggling to hear and understand his friends while chatting in bustling restaurants. But since my husband is only in his late 30s, I was shocked when he was unexpectedly diagnosed with moderate hearing impairment. My husband is not alone: Over 1.5 billion (or nearly 20% of the global population) live with a hearing impairment, and this prevalence continues to grow, including in young to middle-age adults.
My husband is fortunate to have access to great medical care and resources for managing his hearing. But even after a formal diagnosis, he was completely unaware about the deleterious effects of hearing impairment on other areas of health, specifically the brain. As a nurse scientist focused on health behaviors and cognition, I understand the significant roles lifestyle and chronic health conditions have in overall brain health and dementia risk. Nonetheless, I was surprised that his healthcare team did not mention how hearing impairment can negatively impact the brain, even in midlife.
Hearing Impairment and Dementia Risk
Globally, hearing impairment in early adulthood or midlife is the single greatest risk factor for dementia. Dementia, the devastating chronic decline of mental processes, affects over 55 million adults globally. Hearing loss is the top modifiable risk factor for dementia prevention and is linked with over 8% of dementia cases globally. This means that a staggering 800,000 new cases of dementia each year are attributable to hearing impairment.
Our understanding of the exact mechanisms through which hearing impairment contributes to the development of dementia is still emerging, making patient education admittedly very difficult. Since hearing loss can be attributed to a variety of factors across the lifespan (such as genetic factors, infections, chronic diseases, and environmental drivers), it is difficult to determine how it develops. But regardless of the initial cause, hearing impairment in midlife has been shown to be related to decreased brain volume. Changes in brain structure can occur years or decades before changes to memory, thinking, or attention. Another theory is that hearing impairment can lead to a natural deterioration in one's ability to socialize and maintain relationships. Hearing impairment could also impact the ability to engage in other enriching activities that are known to benefit long-term brain health, such as learning a new language, attending lectures, playing games, or playing an instrument.
Strategies to Mitigate Risk
Luckily, there are hearing intervention strategies to offer patients to mitigate dementia risk. Most promising is providing hearing aids in those with mild-to-moderate hearing impairment, similar to what is being tested in an ongoing trial and shown effective in smaller studies. However, hearing aids are not a simple solution. Hearing aids are wildly expensive and even with insurance or Medicare, accessibility is a major barrier. Besides cost, the stigma of hearing aids is incredibly pervasive, spanning all age and gender groups. Many adults report that they don't want to use the hearing aids due to this stigma, even when hearing aids are recommended as a result of known hearing impairment. However, this may improve over time due to evolving technology that makes hearing aids more useful and nearly invisible to others.
To complement hearing interventions, clinicians can also suggest participation in enriching activities. Research supports physical, cognitive, and social activities to help bolster cognitive reserve, or the ability to maintain memory or thinking despite injury or insult to the brain. Luckily, many activities that clinicians can recommend to boost cognitive reserve also support overall health and wellness. Clinicians can suggest low-cost or free activities, including brisk walking, crafts, socializing with loved ones, reading, or puzzles.
Hearing impairment is a highly prevalent health condition with serious consequences for brain health, and your patients are likely uninformed. Clinicians that treat adults -- of any age -- should be knowledgeable about the early symptoms of hearing impairment and assess risk factors for hearing loss (e.g., family history, exposure). Clinicians should encourage patients with hearing impairment to seek out hearing interventions. They should emphasize that newer technology allows for hearing aids to be smaller, use Bluetooth to connect with smart phones, and have built-in trackers to prevent losing them. Patients should be encouraged to engage in activities they enjoy that also support cognitive reserve across the lifespan.
We must better inform our patients about the dementia risk that accompanies hearing loss, while emphasizing that promising strategies and interventions are available.
Shannon Halloway, PhD, RN, is an associate professor and the Heung Soo & Mi Ja Kim Endowed Faculty Scholar at the University of Illinois Chicago. She is the principal investigator of the MindMoves trial that tests lifestyle interventions to prevent memory loss, and is a former Public Voices Fellow of the OpEd Project.