There have been a number of studies conducted in recent years to try and understand if there is a link between hearing loss and cognitive decline, and the research continues to indicate that there is a correlation between the two. The question that researchers are now trying to answer is whether people with hearing loss can mitigate the slope of cognitive decline by treating their hearing loss.
The answer to this question is very tough to parse out because of how many other variables are involved, which makes it difficult for researchers to really isolate the equation down to hearing loss, hearing loss treatment (i.e. hearing aids), and cognitive decline. Since hearing loss often becomes more commonplace as we age, it could just be that both hearing loss and cognitive decline are byproducts of aging. That said, the two could be deeply linked, as suggested by Dr. Piers Dawes’ “cascade hypothesis” where, “long-term deprivation of auditory input may impact on cognition either directly, through impoverished input, or via effects of hearing loss on social isolation and depression.”
In other words, correlation does not necessarily equal causation, and therefore research that tries to get to the answer of this question must be thorough in effectively isolating the variables being measured together from the co-variables that might skew the data.
Today, I came across a paper published in ENT & Audiology news by Dr. Catherine Palmer, PhD Audiologist and Director of Audiology at the University of Pittsburgh, that revolved around research attempting to solve this question. In the paper, this quote here really jumped out at me:
“In a US population-based longitudinal cohort study, 2040 individuals over the age of 50 had cognitive performance measured every two years over 19 years, and new hearing aid use was identified along this time period. After controlling for a number of covariates (e.g. sex, age, education, marital status, wealth, smoking, drinking, physical activity, depression, etc.) the authors determined that hearing aid use had a mitigating effect on the trajectory of cognitive decline in later life. In other words, those who received hearing aids, regardless of many other covarying factors, had a less steep slope toward cognitive decline.”
These findings, along with Dr. Piers Dawes research that was published in January 2019, both indicate that treating hearing loss might change the trajectory of dementia to some extent and lessen the slope toward cognitive decline.
Back in May, I wrote an update about an interview I did with Dr. Nicholas Reed of Johns Hopkins for Oaktree TV about this very topic. During our conversation, Nick stated that along with Johns Hopkins’ study currently underway to try and answer this question, Johns Hopkins has conducted research that has found hearing loss leads to higher healthcare costs (outside of hearing loss related expenses), more frequent hospitalizations and increase in certain cognitive-related comorbidities. All the more reason why hearing loss is such a serious issue:
So, while there is not sufficient research to definitively say whether treating hearing loss can undoubtedly mitigate the potential of cognitive decline, one has to wonder, what if it does? Keep in mind that in the US healthcare system, hearing aids are considered “elective” status (same as plastic surgery) and are largely un-insured. Wouldn’t this finding help to strengthen the argument that these are not “nice-to-have” devices and actually “need-to-have” devices? Food for thought.
-Thanks for Reading-
Dave
