Connecting the Dots: Hearing loss, cognitive decline, and dementia

Did you know one in three people over the age of 65 experience hearing loss?

Aside from not being able to hear as well as you used to, hearing loss can have a multitude of effects on your life. Your ability to hear can play a big role in how you live and your quality of life, with many people unaware of the crucial link between maintaining good hearing and healthy ageing. 

In fact, when left untreated, hearing loss will cause your brain to work harder to process sounds, which in turn increases your risk of cognitive decline and developing dementia.

The negative effects of hearing loss are often compounded by social isolation, which can further exacerbate cognitive decline by limiting mental engagement and stimulation. Therefore it’s crucial to be proactive about your hearing health and address hearing loss early to help promote a higher quality of life in your 60s and beyond.

Where’s the evidence?

Speaking in the recent Starts at 60s Masterclass on World Hearing Day, one of the most experienced cochlear implant surgeons in the world, Dr Catherine Birman said your risk of cognitive decline and hearing loss depends on your level of hearing loss.

Dr Birman referenced a study by professor Frank Lyn at John Hopkins University, in which people aged 65 years and older were observed to find a link between hearing loss and cognitive decline, and dementia. 

“They found that over a period of ten years if you had a mild hearing loss you had a two-fold risk of developing dementia over that ten-year period,” she said. 

“If you had moderate hearing loss, [you had] a three-followed risk, and if you had severe or profound, a five followed risk of developing dementia over a ten-year period.  

“So the degree of hearing loss is really important as well.”

Dr Birmin stressed the importance of early treatment for those experiencing hearing loss, citing two studies in 2017 and 2020, produced by The Lancet.

“They identified that hearing loss if you look at a whole journey of somebody through the whole lifespan, but hearing loss in middle age was responsible for eight to 9 per cent of actual dementia in old age,” she said. 

“So that’s really identified that we actually need to be doing something much more proactive from middle age onwards about our hearing.”

However, Dr Birmin said while there are many theories surrounding the link between the issues, the linking mechanism is still unknown how hearing loss can lead to cognitive decline and dementia.

“One theory is that, in fact, it is not causing it,” she said.

“There are just common causes for both hearing loss and for cognitive impairment such as smoking or hypertension or cardiovascular disease.  

“Something else is causing both of these and we just see an association.”

So, is there a link?

Dr Birmin said there are three major links between hearing loss and cognitive function. 

• One thing we know for certain is that hearing loss and social isolation go hand-in-hand, and multiple studies have shown that “reduced socialisation” is a major risk and cause of a decline in cognitive function. 
• Age-related hearing loss can lead to “shrinkage of the brain”, particularly to the area that recognises auditory sound, however, this often leads to shrinkage of the whole brain. 
• Hearing loss causes an increase in your cognitive load, meaning that the brain must work harder to process sounds, leading to changes in brain structure, and function over time, potentially contributing to cognitive decline and even dementia

But the good news is, if you know someone who is in denial about their hearing loss there’s still hope! 

“What we know is that if hearing loss is the most common risk factor that you can affect, and that is in middle age, then we really need to be screening for hearing loss from middle age,” Dr Birmin said.

“So we often say 55 or 50, we can’t wait for people to miss out and have that time where they’re not having some support for their hearing, either through hearing aids or cochlear implants.” 

Interested in learning more about the relationship between healthy ageing and hearing loss, and what you can do? Re-watch our Masterclass here.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.