By Lisa Rapaport
Older adults with hearing loss may be more likely than peers without hearing difficulty to develop symptoms of depression, a research review suggests.
Globally, more than 1.3 billion people currently live with some form of hearing loss, and their ranks are expected to rise with the aging population, the study team noted March 5 online in The Gerontologist. About 13% of adults 40 to 49 years old have hearing loss, as do 45% of people 60 to 69 years old and 90% of adults 80 and older, the authors write.
To assess the connection between hearing loss and depression, researchers analyzed data from 35 previous studies with a total of 147,148 participants who were at least 60 years old.
Compared to people without hearing loss, older adults with some form of hearing loss were 47% more likely to have symptoms of depression, the study found.
"We know that older adults with hearing loss often withdraw from social occasions, like family events because they have trouble understanding others in noisy situations, which can lead to emotional and social loneliness," said lead study author Blake Lawrence of the Ear Science Institute Australia, in Subiaco, and the University of Western Australia in Crawley.
"We also know that older adults with hearing loss are more likely to experience mild cognitive decline and difficulty completing daily activities, which can have an additional negative impact on their quality of life and increase the risk of developing depression," Lawrence said by email.
"It is therefore possible that changes during older age that are often described as a 'normal part of aging' may actually be contributing to the development of depressive symptoms in older adults with hearing loss," Lawrence said.
The connection between hearing loss and depression didn't appear to be influenced by whether people used hearing aids, the study also found.
One limitation of the analysis is that it included studies with a wide variety of methods for assessing hearing loss and symptoms of depression.
Still, the results of the analysis do add to evidence suggesting that there is a link between hearing loss and depression, said Dr. Nicholas Reed of the Cochlear Center for Hearing and Public Health at Johns Hopkins University School of Medicine in Baltimore.
First, hearing loss impairs communication and influences balance, which can lead to social isolation and decreased physical activity that, in turn, result in depression, Reed said.
Hearing loss may also cause tinnitus, or perceived ringing or buzzing in the ear, that can be especially debilitating in some cases and contribute to depression, Reed, who wasn't involved in the study, said by email.
In addition, hearing loss may trigger changes in the brain that contribute to depression.
"When we experience hearing loss, it also means that we're sending a weaker auditory signal to our brains for processing," Reed said. "This weak signal may mean our brains have to go into overdrive to understand sound (i.e. speech) which may come at the expense of another neural process (i.e., working memory). Also, the weak signal may cause certain neural areas and pathways to reorganize, which could change how our brain, including aspects that regulate depression, function."
While the study doesn't examine whether treating hearing loss can prevent depression or other health problems, people should still seek help for hearing difficulties, said David Loughrey, a researcher at the Global Brain Health Institute at Trinity College Dublin who wasn't involved in the study.
"Hearing loss has been linked to difficulties in daily life including difficulty with socializing and fatigue due to the increased mental effort required to understand speech, especially in noisy environments," Loughrey said by email. "If someone is experiencing difficulties due to hearing loss or if they have any concerns about their mental wellbeing, they should consult a medical professional who can assist them."
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