There are many practical downsides to losing your hearing, but in recent years, research has indicated a disturbing correlation between hearing loss and cognitive decline. Nobody has been exactly sure what this is – until now.
Because the evidence has stacked up that the two issues must be connected, especially among older people, various hypotheses have been advanced on how exactly losing your hearing is linked to cognitive decline.
Whatever the causes, any connection is a good reason to get a free hearing test, because a hearing aid could do more than just help you hear clearly; it can preserve cognitive function, too.
Has New Research Worked Out The Connection Between Hearing Loss And Cognitive Decline?
A popular idea has been that the brain is damaged by the strain placed on it in trying to understand words and sounds that are no longer as loud or distinct as they used to be. But it may be something more complex.
Researchers in China believe they have now found a smoking gun, in the form of changes to the brain associated with both cognitive decline and age-related hearing loss.
The findings, published in the journal eNeuro, observed that in the case of presbycusis, the most common form of age-related hearing loss, MRI scans have revealed the same structural changes in the brain that are associated with cognitive decline.
Presbycusis is characterised by a struggle to hear words and sounds at higher frequencies, where consonants are pronounced without using the vocal cords, such as F and P.
What Is New About The Latest Study On Hearing and Cognition?
However, while this link was already known to an extent, this study identified a mechanism by which poor hearing correlated with cognitive decline, based on a measurement called the structural-functional ratio (SFR). This combined three factors:
· Measurements of how a particular area of the brain was functioning, called the amplitude of low-frequency fluctuations
· Volume of grey matter as a measure of structure in a particular area
· By dividing the first by the second, they produced an SFR reading. The lower this was, the worse the brain function.
The key finding was that the SFR was lower in certain parts of the brain among test subjects with serious hearing loss. These corresponded with lower scores in cognitive tests.
As the areas in question were respectively locations strongly associated with sound recognition, and areas closely linked to memory and decision-making, there appears to be a causal relationship.
“This provides the first direct neurobiological evidence linking hearing loss to cognitive decline via shared neural reorganisation,” the researchers stated.
Is Poor Hearing Causing The Brain To Decline, Or The Other Way Round?
However, while this firms up evidence of a link, it still leaves unanswered the key question of whether hearing loss leads to changes in the brain or is caused by them. More research will be required to examine this question.
If it is the first of these, this provides an even stronger reason to get a hearing test, as it would mean that if your hearing is weakening but then boosted by a hearing aid, it could help prevent the kind of brain issues that could translate into cognitive decline.
Previous studies indicating a link – without connecting it in the way devised through the SFR measurement method – have suggested that there is a great opportunity to reduce cognitive impairment through providing solutions to those with hearing issues.
Ultimately, being able to hear well in later life has great social benefits by helping you to interact with others, preventing isolation. If it can protect you from dementia as well, that is even better.