Does Hearing Loss Impact Cognition?

0
23

By Douglas L. Beck, Au.D. Doctor of Audiology

This is an often-asked question among professionals and among people with hearing loss.
The answer is variable and not as straightforward as any of us would like. One of the reasons this question is so difficult is that it may be the wrong question (see below). The answer which I have published previously, and with which I am very comfortable goes like this: “Untreated hearing loss may exacerbate cognitive decline, and even more so as hearing loss increases.”

Hearing is simply detecting or perceiving sound. Listening is comprehending or understanding, or applying meaning to sounds. Listening involves auditory processing, information processing and is more-or-less a ‘whole brain’ event. Cognition can be defined as knowing and acquiring knowledge through sensory input (like vision and hearing) experience and thought processes. As such, the distinction between hearing and listening is pivotal in that listening and cognition involve active and intricate brain-based processing, whereas hearing is simply a detection task, requiring almost no processing at all.

Leavitt, Beck and Flexer (2023) noted the more appropriate question might have been “Would the correlation between listening and cognitive decline be even greater than those reported for hearing and cognition?” Probably yes. But measuring listening is very difficult, and measuring hearing is very easy.

As noted above, untreated hearing loss does appear to increase the risk of cognitive decline. This is not a new observation. Peters et al (1988) reported cognitive decline was greater in hearing impaired individuals and for those with Alzheimer’s Disease, hearing impairment predicted a more rapid cognitive decline. Gold and colleagues (1996) reported a high prevalence of hearing loss in individuals with cognitive deficits.

Beck & Clark (2009) wrote that patients live in a world where cognition, attention, memory, and hearing interact and each plays a critical role in listening. They reported that people with hearing loss must dig deep into their cognitive reserve and cognitive abilities to make sense of a world delivered to them via compromised auditory input. Beck & Clark stated “audition matters more as cognitive ability decreases, and cognition matters more as auditory ability decreases.”

Edwards (2013) reported there exists increasing evidence that hearing loss can result in cascading cognitive and psycho-social declines as well as increased cognitive load, mental fatigue, poor memory, worse auditory scene analysis, reduced attention, less focus, worse mental health, social withdrawal, and depression. He noted hearing aids may be beneficial as they may improve the quality of the auditory signal impacting the cognitive system.

Amieva, Ouvrard, Giulioli and colleagues (2015) studied 3,670 people over a 25-year period, based on self-perceived hearing loss and hearing aid use. They concluded that those who reported hearing loss had lower cognitive screening scores and they declined more rapidly than those who did not report hearing loss. Interestingly, for those with hearing loss who used a hearing aid, there was no difference in cognitive decline from the control group. The authors stated “Self-reported hearing loss is associated with accelerated cognitive decline in older adults; hearing aid use attenuates such decline.”

More recently, Livingston, Huntley, Summerland and colleagues (2020) published a ground-breaking article on dementia. They reported that some 60% of your risk for e=dementia was due to aging and deoxyribonucleic acid (DNA), and the other 40% was due to 12 potentially modifiable risk factors. Of the 12, untreated hearing loss was the most significant with an 8.2% population attributable factor (PAF). The complete list includes; “Risk factors in early life (education), midlife (hypertension, obesity, hearing loss, traumatic brain injury, and alcohol misuse) and later life (smoking, depression, physical inactivity, social isolation, diabetes, and air pollution).”

Jiang, Mishra, Shrestha (2023) reviewed data from 430 thousand people who participated in the UK Bio Bank study. Participants were asked “Do you have any difficulty with your hearing?” and “Do you use a hearing aid most of the time?” There were three groups of responses. (1) no reported hearing difficulties; (2) hearing difficulties with hearing aid use (3) hearing difficulties without hearing aid use. The authors reported study participants with hearing difficulties who did not use a hearing aid had a higher risk of later being diagnosed with all-cause dementia than those without hearing loss. Participants with hearing difficulties who used a hearing aid did not. They also reported “up to 8% of dementia cases could be prevented with proper hearing loss management, our findings highlight the urgent need to take measures to address hearing loss to improve cognitive decline.”

Bottom Line: It appears extremely likely that untreated hearing loss increases the risk of cognitive decline in many people—not all. The risk of cognitive decline varies tremendously based on DNA, age, overall cognitive, emotional, physical health, the type and degree of hearing loss and much, much more.

Regarding whether hearing aid fittings slow cognitive decline, and if so, would OTC and prescription hearing aids offer the same benefit? No one knows. There are certainly studies which have found that treating hearing loss with professionally fit hearing aids appears to have a “normalizing effect” (see Amieva, 2015, and see Jiang, Mishra and Shrestha 2023), but this did not occur with every single participant. Further, there are no peer-reviewed studies regarding OTC and long-term cognitive outcomes.

If I had to make a strong statement on these matters in Fall 2023, I am comfortable saying the following:

• Untreated hearing loss increases the risk of cognitive decline in many people.
• Professionally fit hearing aids often appear to be useful regarding altering the trajectory of cognitive decline in high risk, willing and able people.
• Just like in all other areas of medicine and healthcare, early detection and treatment is the most successful and most likely to succeed.

For an appointment: Grant Williams, HAS, HIS, Audioprostologist | Niceville Hearing Center | Florida State Licensed in Hearing Instrument Sciences | 850-830-0376 | GrantEarCare@gmail.com.