New Studies on Hearing Loss and Dementia

New Studies on Hearing Loss and Dementia

In Dementia & Alzheimer's, Hearing Health, Hearing Loss, Research by Jack Felix, ACA, BC, HISLeave a Comment

Jack Felix, ACA, BC, HIS

Incredibly, our brain doubles in size in the first year of our lives and continues to grow to about 80% of adult size by age 3. By the time we are 5, 90% of our brain is fully formed.  brain processing power and memory peak at the age of 18 and as we age it slowly starts to slow down. It’s completely normal for our cognitive function to decline as we age. In fact, by the age of 45, cognitive functioning starts to decline affecting memory and reasoning. However, that doesn’t stop us from being spry and alert into our later years -especially when we take care of ourselves. What may come as a surprise to many, one way to keep our brain clear and bright is by addressing a hearing loss early.

Addressing Dementia

Dementia is a grouping of neurodegenerative diseases classified by the loss of two or more cognitive functions such as memory, social behavior, reasoning, and problem-solving.  One of the most common types of dementia is Alzheimer’s disease making up nearly 80% of the approximate 55 million cases worldwide. The World Health Organization projects that “over 60% living in low- and middle-income countries. As the proportion of older people in the population is increasing in nearly every country, this number is expected to rise to 78 million in 2030 and 139 million in 2050” Nobody completely understands what causes dementia however there are many suspected causes such as environmental toxins, impact to the head, a poor diet, lack of socialization and a sedentary lifestyle. Interestingly enough, another risk factor for dementia is hearing loss which can contribute to many of the previously listed risks. 

Speech in Noise Impairments

A July 2021 paper published online by the Alzheimer’s Association titled “speech-in-noise hearing impairment is associated with an increased risk of incident dementia in 82,039 UK Biobank participants” explored the risk of hearing loss in a wide range of patients. While the most common hearing tests can detect hearing impairments in a quiet environment, rarely do tests detect issues hearing in noise. While many people, especially of a younger demographic have no trouble hearing sound when in a quiet setting, issues hearing in noise can be attributed to damage in the auditory cortex of the brain due to noise.

The paper found that the hearing of people in this category is often deemed “normal” in traditional tests, and are at a much greater risk of developing dementia.

To explore whether speech-in-noise hearing impairment was linked with increased dementia risk, the study examined   82,039 people aged 60 or over. The participants were followed up over 11 years to monitor and record who from this large cohort developed dementia. The findings showed that a total of 1,285 people from the 82,039 total received a dementia diagnosis over that period and that for those with a significant speech in a hearing challenge, 91% had a greater risk of developing dementia compared to those with normal speech-in-noise hearing. 

Why Speech and Hearing can Affect Cognitive Function

We collect sound with our ears, but we hear with our brains. Sound travels into our outer ear down our ear canal to the inner ear where tiny hair-like cells send sound to our brain. There are several ways that these cells can be damaged such as exposure to noise, ototoxic chemicals, and even changes to the ear as we age. However, once they are damaged, they cannot regenerate causing permanent hearing loss. When we struggle to hear it leaves huge breaks in words and sentences. This causes our brain to strain to fill in the blanks which can cause us to cognitively strain. The parts of sound which can’t be received by the brain often go dormant, causing cells to die and the brain to atrophy as well.

Treating a Hearing Loss

Often a speech in noise hearing loss can be due to neurological damage caused by listening to loud noise due to concerts or even headphone use. It isn’t caused by traditional sources of hearing damage but can be one of the first warning signs of increased risk for dementia. However, when you address a hearing loss early it can significantly decrease the risk of damage. To find out how you can keep your brain clear and spry for years to come schedule a hearing exam with us today!

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