The Connection between Your Brain & Your Hearing
The brain and the ears are connected in some amazing ways.
- Dementia Correlations
- Adjusting to Life with Hearing Aids
Hearing Loss and Dementia: Examining the Link
Hearing loss and dementia are both major issues in the current and future health care landscape. By 2050, when the proportion of people over 60 will have doubled, there will be more than 141 million people with dementia and 580 million people with hearing loss living in the world, with associated healthcare costs in the trillions of dollars. Continuing research suggests that the two conditions – hearing loss and dementia – are likely linked, and a recent Lancet study identified hearing loss as one of the highest potential risk factors for developing dementia. In fact, many of their symptoms are similar, including:
• confusion during conversation
• changes in the methods and frequency of communication
• mental fatigue
While there is no definitive proof of a causal relationship between hearing loss and dementia, the shared symptoms and correlation of incidence suggest the possibility of a common underlying pathology and could explain the growing link between the severity of hearing loss and cognitive decline. Because of these connections, research has indicated that proper early diagnosis and treatment of hearing loss can potentially soften the trajectory of cognitive decline later in life.
The leading theories regarding the correlation between hearing loss and dementia both involve cause and effects:
Information Degradation: This theory suggests that hearing loss increases the demands on the brain’s resources, causing it to spend more cognitive energy as it strains to hear and understand information, which can, in turn, draw energy away from other areas of the brain. As more brain power is used to decipher the auditory information coming in, other cognitive functions, such as memory, are reduced, contributing to cognitive decline.
Sensory Deprivation: This theory suggests that hearing loss causes social isolation, as people become cut off from conversations and the community of shared information. If a person cannot follow what’s being said, they may lack the confidence to participate. This can contribute to a person becoming withdrawn and disengaged socially, eliminating many of the complexities of everyday interactions that the brain relies on to stay exercised and sharp.
There is still a gap in determining the exact nature of the relationship between hearing loss and dementia, whether one may cause the other, or how a third factor may cause both. However, the evidence suggests, at the very least, a connection exists. It’s possible that if hearing loss is diagnosed early and accurately and then treated properly, that treatment can have a strong positive effect on future cognitive function and memory retention. Due to improved signal processing and sophisticated design, hearing aids have become more adept at navigating the challenges of their auditory surroundings, making them a perfect tool to reduce the cognitive load for those with hearing loss, easing the stress on memory and executive function.
Treating hearing loss as a public health issue and encouraging people to access the advances made in technology could help to lower the number of people who potentially suffer cognitive decline as a result of hearing loss, as well as reduce the strain on our healthcare system as the population ages.
1. APA Wolfgang, Kelly Hearing Loss and Dementia, The Hearing Journal: September 2019 – Volume 72 – Issue 9 – p 22,23,26
Pupillometry: Eyes Are a Window to the Brain
Pupillometry measures pupil dilations of the eyes while the brain executes various tasks. Studies have shown that pupil activity is a solid indicator of how the brain is expending effort while it processes inputs. Researchers have found that as people pay attention to sound, muscles in the eyes contract and release based on the effort expended by the brain to hear and decipher incoming auditory information. Using pupillometry, researchers can now measure the effort exerted by the brain, in real time, as it processes audio in various real life listening environments. Factors such as noisy settings, a lack of visual cues, and differing accents and dialects can all increase the cognitive load, forcing the brain to expend more effort to decode what is said.
This diversion of cognitive resources takes away energy from other important functions such as memory retention and short term recall. Pupillometry allows researchers to begin to separate and untangle the various cognitive factors affected by hearing loss. Measuring the dilation of the pupil can provide a more direct understanding of which auditory obstacles are most challenging for the listener on an individual basis, so that treatment can become more focused and precise for each patient’s needs.
Accurately diagnosing specific hearing impairment challenges is also critical for evaluating potential solutions. Hearing aid researchers can now use pupillometry to better assess the effectiveness of products and perhaps someday allow for even more individualized custom care solutions than what we have today for each unique patient. While studies have shown that there are many overlaps between the factors that affect pupil response, pupillometry is an important tool that can help us to separate and observe these cognitive processes so that we may better understand the brain, how it hears and interprets sound, and how to use it to treat patients with hearing loss.
1. Van Engen KJ, McLaughlin DJ. Hearing research. 2018 May 4; 369: 56-66
2. Zekveld AA, Koelewijn T, Kramer SE. Trends Hear. 2018 Jan-Dec; 22:2331216518777174.
3. Kuchinsky, Stefanie E et al. “Speech-perception training for older adults with hearing loss impacts word recognition and effort.” Psychophysiology vol. 51,10 (2014): 1046-57. doi:10.1111/psyp.12242