Our five senses – seeing, hearing, tasting, smelling, and touching – are cornerstones of our experience. Without these senses, we’d have no way to interact with the world around us or any way to understand our environment. That being said, plenty of people around the world live with some form of sensory impairment, whether that be a decreased sense of smell or a loss of vision in one eye.
While many people with some form of sensory loss find that their other senses can compensate for the loss without any other issues, a new study is investigating the connection between hearing loss and cognitive impairment in adults. Since there is no obvious reason why a hearing-impaired individual should exhibit anything other than normal cognitive function this study may shed some light on how the brain develops and operates in the absence of sound.
The Study
This study, conducted by researchers at Ohio State University, investigated the connection between hearing loss severity and different levels of cognitive impairment in young and older adults. The researchers examined 35 young, healthy, adults between the ages of 18 and 41 with normal hearing and monitored their brain activity in response to hearing sentences of varying length and complexity.
Normally, one would find that the left frontotemporal cortices (the part of the brain around the ear and forehead) are the center of the “language network” in the brain. But, the researchers found that while the left frontotemporal regions were particularly active during the listening tasks, another area of the brain – the right anterior prefrontal cortex – was also active.
This may not seem like a groundbreaking finding – more brain involvement is a good thing, right? – but it turns out that the right anterior prefrontal cortex of the brain generally gets involved with language processing as someone’s hearing acuity decreases. In other words, this part of the brain often compensates for decreased brain activity in the left frontotemporal region as one’s hearing decreases through normal aging processes.
A shift in brain activity in adults generally suggests some amount of plasticity – or the ability of the brain to adapt to decreasing functionality in one area of the brain by switching the role of another region to compensate. While the current research cannot establish a causal relationship between hearing loss in adults and cognitive impairment in the long term, early onset of this brain plasticity could indicate a decrease in potential neural resources as one ages because these previously ‘unused’ brain areas are now involved in sensory processing.
Implications For The Future
All this talk of brain plasticity and sensory processing might seem a bit abstract, but it may have real-world implications for the hundreds of thousands of people who have or are at risk of hearing loss. These days, the concern is increasing about the potential of hearing loss in young adults who are more frequently exposed to noise at dangerously high levels.
Whether it’s construction work, exposure to loud music at a concern or through listening to headphones, or from dining and drinking at noisy restaurants and bars, the vast majority of young adults are regularly exposed to sound levels that can cause hearing loss. Thus, it is imperative that we understand the effects that this hearing loss can have on people throughout their lives.
This study from researchers at Ohio State University is one of the first to investigate the potential impact that hearing loss can have on cognitive abilities. As young people are more frequently exposed to dangerously high noise levels, research such as this can help us better understand the wide-reaching effects that hearing loss can have on people so that we can develop better treatment and prevention strategies.
