Hearing loss is very common and it effects people of all ages. There are many reasons for hearing loss including hereditary factors, noise exposure, trauma and ear disease. Hearing loss becomes more common as we age. Research shows increased severity of hearing loss is correlated to increased memory loss and dementia.
This graph shows the results from a study by the National Foundation of the Deaf called Social and economic costs of hearing loss in New Zealand (published in December 2016).
Hearing loss is usually gradual. In the beginning, hearing loss takes away the beginning of the sentence, the little details and the punchline. With time hearing loss may increase mental fatigue – as you concentrate harder just to follow along. It can begin to erode your confidence – as you are no longer sure about what was said and it can lead you to feel embarrassed about missing the details or about having to ask for repeats too often.
The gradual nature of hearing loss means that we adapt over time. We change our behaviour, we choose our environments and slowly our relationships change as everyone adapts to a change in our hearing. Often hearing loss leads people to socialise less, which can lead to less overall activity. Hearing loss is also linked to memory loss and dementia (or cognitive decline).
Hearing loss is invisible and sneaky.
As hearing changes, we adjust.
Gradually it effects personality and relationships.
Hearing loss changes us over time.
Maree O’Sullivan (Audiologist)
Hearing loss is linked to memory loss and dementia
In 2013, Frank R. Lin, MD, Ph.D conducted a study on the topic of hearing loss and cognitive decline. The study observed 1,984 adults over the course of six years, tracking the progression of their hearing loss in relation to their cognitive function. He found that there is little doubt that hearing loss is a factor affecting loss of mental acuity in older adults.
The study found that the people with more severe hearing loss, had a greater likelihood of developing a cognitive disorder, and an increased decline in mental function. Even subjects with mild hearing loss were found more likely to experience cognitive difficulties like memory loss and dementia, it is also linked to increased falls.
The exact link between hearing loss and cognitive decline is not yet fully understood and current studies are focusing on this question. It is possible that is due to increased “cognitive load”, where the brain is overwhelmed with demands on its limited resources. Concentrating hard to follow the conversation means we have fewer resources for other things like memory and maintaining balance.
“Communicating when you have a hearing loss, takes up lot of brain power. It’s a bit like a computer that runs slower when there is a large program running in the background.” says Maree O’Sullivan, Audiologist from Auckland Hearing.
There is evidence that the part of the brain that was used by the hearing system gets reallocated and is used by the visual system in people with hearing loss. “Declines in hearing abilities may also accelerate grey matter atrophy and increase the listening effort necessary to comprehend speech. Hearing aids may not only improve hearing but preserve the brain,” said Dr. Lin.
Hearing aids may help reduce memory loss and cognitive decline
As evidence continues to mount that hearing loss is a contributing factor in the development of memory loss and dementia, it is imperative to consider the profound consequences of ignoring hearing loss. People with hearing loss on average wait ten years from when they are first diagnosed before they seek treatment; even though the sooner hearing loss is detected and treatment begins, the more hearing ability can be preserved. “Considering early diagnosis and medical intervention of hearing loss slows the progression of dementia and Alzheimer’s disease, it is more important than ever for patients to get their hearing loss treated sooner rather than later,” said Maree O’Sullivan – Audiologist at Auckland Hearing.
Research has shown that people that wear hearing aids do not show the same cognitive decline as those who don’t. However, although there is a definite co-relation, Dr Frank Lin and his team are not prepared to assume causation. This means that we can not assume that wearing hearing aids reduces cognitive decline. This is because the reduced cognitive decline measured may, in fact, be due to other factors, for example, education levels or socioeconomic factors that may lead some people to get hearing aids and others to choose not to. A very large study is currently underway by Frank Lin and his team to clarify whether wearing hearing aids protect from memory loss and dementia when taking into account other factors.
At Auckland Hearing we see positive change in our clients after they get hearing aids, anecdotal evidence that hearing aids keep you active. We often measure improvement in our client’s ability to understand speech (using speech perception testing), once people with hearing loss start wearing their hearing aids all day every day. Human brains have plasticity which means they are continually adapting. Once people retrain their brains by exposing them to sound every day they hear better, interact more and are more full part of their world.