Dementia and hearing loss

Dr. Inas Alrubaye is currently a Doctor of Audiology at Livingston Hearing Aid Center, a position held since September 2023. Previously, Dr. Alrubaye worked as an Audiologist at All About Hearing from May 2019 to September 2023 and served as a Hearing Aid Specialist. Additional experience includes being a Clinical Audiologist at a hospital in Iraq from November 2013 to November 2016. Dr. Alrubaye holds multiple degrees in audiology, including a Doctor of Audiology from Salus University and multiple master’s degrees in audiology from the University of Baghdad.

Through this article, Dr. Alrubaye highlights the connection between hearing loss and cognitive decline, emphasizing that hearing intervention, such as hearing aids, may help reduce the risk of dementia by improving social engagement, reducing cognitive load, and preserving brain structure.

People with hearing problems in midlife (40-65) are more likely to develop dementia. Hearing loss is also an early sign of dementia. Many people experience hearing loss as they get older, though they may not notice it at first because other symptoms may mask it. It is important to have your hearing tested regularly to reduce your risk of developing dementia in the future.

A study has shown that the use of hearing aids reduces the risk of dementia to the level of a person with normal hearing ability compared to a person without one. Hearing loss is only a risk factor for dementia, and it is not guaranteed that a person with hearing loss will develop dementia as a result of it.

Could this hearing intervention help if a person has other risk factors for cognitive decline than simply being older?

Theoretically, when people get hearing intervention, it is always possible that it may support cognitive function over the long run. In fact, it is more important to consider the more immediate benefits of hearing intervention, such as improving communication and helping people engage in social activities more effectively. 

The clinical takeaway is that just about anyone with hearing loss, such as an older adult, should have their hearing checked and address any issues they might have with their hearing if they do. There is no downside to this. There is no risk associated with hearing intervention. 

Can taking it when you are cognitively healthy and in the short term help your cognition in the long term?

No, in the short term, but in the long run, it may have a positive impact on cognition.

Is there a link between hearing loss and cognitive decline that we need to understand? 

Three main theories can be attributed to this phenomenon.

The first thing to consider is that people with hearing loss may not be as socially engaged as people without hearing loss. As a result, they may become lonelier or withdrawn. When it comes to the risk of dementia and cognitive decline, we know one thing for sure: If people do not engage in cognitively stimulating activities, their brains are less likely to remain healthy. 

The other theory is that when you lose hearing, your brain does not receive a clear sound from your ear. Hence, it compensates by reallocating resources to assist with hearing at the expense of thinking and memory abilities or by helping protect your brain from other pathologies that can lead to dementia if you are not getting a clear sound from your ear. There's no doubt that hearing loss can cause dementia, but it is also true that hearing loss taxes the brain. It can lead to earlier exposure to dementia as a result of other factors that can contribute to dementia. This is what is known as the cognitive load hypothesis. 

Thirdly, it is thought that hearing loss can directly negatively affect the structural integrity of the brain. Parts of the brain can begin to atrophy faster if exposed to constant reduced auditory stimulation in parts of the brain. The result of shrinking brains is not suitable for the functioning of the brain, as you can imagine. 

The three theories suggest that treating hearing loss by using something as simple as a hearing aid could directly modify or affect these pathways, which could reduce the risk of cognitive decline.  We treat hearing loss to keep people engaged, which is why we treat it in the first place. From a proof-of-concept perspective, we believe that hearing aids and hearing treatments can play a significant role in improving hearing.

The trial's results show precisely this. The study found that people who received hearing aids reported a substantial improvement in their communication abilities throughout the study.

There was no improvement in hearing and communication in the health-education group, as expected, compared to those in the control group. Researchers found that, in their primary analysis of all study participants, they did not observe any difference in the rate of change in cognitive functioning between those who received the hearing aids and those who did not.

When the analysis was focused on people from the heart health study who had a higher risk of dementia compared to those in the control group, the benefit of hearing aids was very considerable.

The rate of cognitive decline in those who received hearing aids was significantly reduced compared with those in the group who received health education, with an almost 50% reduction. Hearing loss is a relatively treatable condition in later life, which makes it an important public health target to reduce the risk of cognitive decline and dementia in later life.

The researchers are continuing to follow the study participants to determine how changes in cognitive abilities develop over time.

Aside from brain scans, the researchers are also examining data on social engagement to better understand how hearing protection may prevent cognitive decline in older adults who are vulnerable to it.

For general health and well-being, it is recommended that older adults have their hearing checked regularly and that any hearing problems be handled appropriately as soon as possible.