Several studies have shown that people suffering from hearing loss appear to have an increased risk of cognitive decline or dementia, representing a potential breakthrough in the fight against that insidious disease, though there is still much work to be done.
A report published in 2020 in medical journal The Lancet estimated that hearing loss accounts for about 8% of all dementia cases – equal to 800,000 of the new cases diagnosed each year.
One of the most recent reports, published in January by researchers at the Johns Hopkins Bloomberg School of Public Health, found that older adults with greater severity of hearing loss were more likely to have dementia. The likelihood of dementia was 32% lower among hearing aid users than non-users.
The problem here is that the association between hearing loss and developing cognitive decline/dementia has not yet been shown to be causal; we cannot definitively say that a case of cognitive decline is, or is not, a byproduct of hearing loss.
But while the question has not been scientifically settled, there is circumstantial evidence that the two may be linked. Someone with a minimal loss of hearing (20 decibels or less) is two times more likely to develop dementia than someone with no hearing loss. Someone with medium hearing loss (41-55 decibels) is three times as likely, and someone with severe hearing loss (70-90 decibels) is five times as likely.
Hearing loss is commonly associated with age. Similarly, the Johns Hopkins study covered 2,413 individuals, roughly half of whom were over 80 and showed a clear association between severity of hearing loss and dementia. The prevalence of dementia among the participants with moderate/severe hearing loss was 61% higher than the prevalence among those who had normal hearing. Meanwhile, hearing aid use was associated with a 32% lower prevalence of dementia in the 853 participants who had moderate/severe hearing loss.
These are striking numbers showing a link between hearing loss and cognitive decline – but, again, it is difficult to draw precise conclusions from such a small sample size.
Also playing a role here is whether or not someone who should be using a hearing aid(s) actually is. According to the National Institute on Deafness and Other Communication Disorders, approximately 28.8 million U.S. adults could benefit from using hearing aids; however, for adults aged 70 and older with hearing loss, less than one in three has ever used them.
Reasons given for not wearing them range from comfort level and appearance to need for maintenance and cost. Though the average price is around $2,000 per ear, they can go as high as $4,000 per ear (over-the-counter hearing aids go for less, but may be less effective than those professionally recommended); most insurance plans do not cover that cost.
Although the “why” behind the link between hearing loss and dementia remains uncertain, I have been encouraged by the ongoing level of research being done in this area. This is one of the main topics at the various national meetings I attend, as millions of lives worldwide would be affected should that link be proven.
It could even lead to the federal government approving Medicare’s paying for hearing aids. Various Congressional bills have failed in the past – in January, the bipartisan Medicare Hearing Aid Coverage Act was introduced in Congress – but if such a game-changing link can be definitely proven, I believe the government would indeed pass such legislation as a means of fighting against dementia.
In the meantime, the studies will continue. Within a few years, we could know considerably more about the subject than we do now.