Hearing loss can lead to changes in the brain. While our ears are the organs which perceive sound, it is the brain which processes what we have heard.
People can experience hearing loss at any age. 11 million people in the UK are deaf or hard of hearing. There have been many studies to explore how hearing loss affects the brain. There are several reasons to explain why this happens and a variety of ways in which loss of hearing impacts on brain function.
Why does hearing loss affect the brain?
The link between hearing loss and brain function is not fully understood. One theory suggests a reduction in hearing leads to less brain activity which leads to cognitive decline. Almost a “use it or the brain loses it” scenario.
Another theory is that pre-existing cognitive impairments can impact upon a person’s ability to process sound which leads to hearing loss that can become progressive as we age.
It is also possible that both effects could combine.
How does hearing loss affect the brain?
Studies have shown that the brain goes through a process of reorganising itself as hearing loss occurs. This is known as cross-modal cortical reorganisation or compensatory brain reorganisation.
The effect is because of the brain’s tendency to compensate for a loss of a sense. The brain essentially rewires itself. By placing additional emphasis on the other senses, the process causes fatigue which can lead to a loss of concentration.
This process can help the person cope with a loss of hearing to some extent but the compensatory adaptation system continues to significantly reduce the ability to process sound which leads to problems understanding speech and language.
This effect is compounded because the higher-level brain processing is forfeited to concentrate resources on understanding speech. The areas of the brain responsible for other functions essentially step in to take over from hearing leaving them unable to perform their primary purpose.
This compensatory effect increases the overall load on the brain, particularly in ageing adults. Recent reports have suggested this is why age-related hearing loss is directly correlated with dementia.
How identifying hearing loss early can slow cognitive decline
Even in the early stages of hearing loss, the brain begins to reorganise itself. Research has shown that even before a clinically defined level of hearing loss is reached, that cognitive ability is already declining. Studies also show that brain function is higher for those without any level of hearing loss.
Early screening for hearing loss could help prevent cognitive decline. It may be that early intervention can halt the changes to the brain. Hearing aids enable people to hear properly and help stimulate brain activity in the areas responsible for processing sound.
Hearing loss is one of the most common conditions affecting older adults. Yet only a quarter of those who require a hearing aid actually seek advice and get one.
It is important not to ignore the signs of hearing loss, even at the earliest stages. This can help avoid changes to the brain in the future.
Any problems such as difficulty in understanding what people are saying in social settings, or requiring the television or radio to be turned up to a volume higher than normal may indicate the onset of hearing loss. But it really does make sense for everyone – regardless of whether they are having trouble hearing or not – to have a regular hearing test.