Hearing loss & the brain

Ever notice how some adults get distracted or tired easily? It may have to do with changes in their brains that are related to hearing loss. Here's a peek inside the brain of someone with hearing loss.

How does hearing affect the brain in the first place?

First we should look at how the brain processes sound in adults. Researchers have studied and continue to study how and where sounds are processed and perceived by the brain. They've found that there's a link between hearing and cognition-the brain's process of perceiving and understanding.

Thanks to magnetic imaging, scientists are able to watch the brain and see how it activates in response to certain sounds. They've discovered that we don't hear with just one part of our brain. The process of hearing also stimulates other brain areas.

For example, when a researcher said a simple word, it activated the auditory cortex. The auditory cortex was where that word was technically heard. But a few other areas of the brain also lit up in the cerebral cortex. Those areas were where that word was understood, perceived  or cognitively connected.

Scientists believe there's a dual-track association between hearing and cognition. Sound activates the auditory cortex, the cerebral cortex and cognitive processes influence how we hear.

We rely on cognitive elements of the brain, like working memory and life experiences, to understand a conversation in a noisy place. Surprisingly, only 10% of understanding speech in a noisy environment is by the actual hearing capacity.

So what happens to the brain when hearing is impaired?

Because there is a decline in sound stimuli and sensory deprivation, hearing loss can lead to  structural and functional changes in the brain. There can be reduced connectivity, brain signal decline, deterioration of the auditory cortex (which is the part of the brain that hears) and a reduction in overall brain volume. These structural and functional changes can affect the brain's capacity to process and perceive sounds and may contribute to cognitive decline.

The brain is forced to compensate for these losses by activating alternative circuits. It enlists accessory neuron networks and that means increased cognitive effort is needed to weed out irrelevant sounds, like background noise, and more concentration is needed for hearing.

A high cognitive effort reduces the amount of brain resources available to process everything else. So things like concentration, memory and planning may be affected. It's easier to get distracted. And constantly decoding and processing sounds can take up a lot of mental resources and can be tiring.

How can this type of cognitive decline be prevented?

Treatment of hearing loss can help keep the brain functioning at an ideal level and can contribute to a good quality of life. There are many hearing solutions and are they are highly effective. In fact, 95% of people with hearing loss can be helped by hearing aids.

It's important to identify and treat hearing loss early. The longer treatment is neglected, the more challenging it can be for the brain to relearn and repair itself. Like physical therapy after a surgery, consistent use of hearing aids is essential in a successful treatment plan.

Certain portions of this article were taken from a blog at Amplifon