En español | COVID-19 has been linked to a long list of unusual symptoms and long-term complications. And now, scientists are studying another potential blow to the body from a coronavirus infection: hearing loss.
It's common for some hearing-related symptoms to accompany any viral infection of the upper respiratory tract, says Elias Michaelides, M.D., codirector of the Auditory Implant Program and medical director of audiology and otolaryngology at Rush University Medical Center in Chicago. That's because the mucous membranes tend to “get very stuffy,” and, as a result, “sometimes fluid can build up behind the eardrums,” he says. This symptom, however, does not cause permanent damage “and often will just clear up on its own” once the infection has passed.
Coronavirus and hearing loss: What doctors know so far
But some studies have found more persistent hearing problems tied to COVID-19. A survey of 121 people in the United Kingdom published in the International Journal of Audiology, for example, found about 13 percent of patients reported a change in hearing and/or tinnitus (ringing in the ears) since their COVID-19 diagnosis. Another report, published in Mayo Clinic Proceedings, details an older COVID-19 patient who experienced deafness with loud tinnitus, even after other symptoms improved; a similar case was described in the American Journal of Otolaryngology.
What's more, a team of researchers from Johns Hopkins School of Medicine found evidence of the coronavirus (SARS-CoV-2) in the middle ear of COVID-19 patients in an autopsy study published in JAMA Otolaryngology — Head & Neck Surgery. While determining the impact of the virus’ presence in the ear was outside the study's scope, corresponding author C. Matthew Stewart, M.D., says it raises some concern, especially given that other viral infections are known to cause hearing loss.
"If there is an active viral infection in that part of the body, you could get the whole host of symptoms associated with other types of viral infections in that area,” including inflammation in the ear that could impair hearing or cause tinnitus, dizziness and imbalance, says Stewart, associate professor of otolaryngology and head and neck surgery at Johns Hopkins School of Medicine.
Researchers have also pointed out that cochlear hair cells, which process sound vibrations, are “particularly vulnerable” to damage caused by restricted oxygen and blood supply — two complications that have been reported in patients hospitalized with COVID-19.
Experts caution there's not enough evidence yet to draw a direct link between a SARS-CoV-2 infection and hearing problems. Still, Stewart argues, “we can be reasonably suspicious” that the coronavirus may affect hearing in some patients.
Medications, masks add to hearing problems
Medical care muddies the waters when it comes to better understanding a possible connection between SARS-CoV-2 and hearing. For starters, a number of factors related to being critically ill can drive hearing loss, especially in older patients, researchers point out. And several drugs currently and previously used to treat patients with COVID-19 — including remdesivir, chloroquine and hydroxychloroquine — are ototoxic, meaning they can cause damage to the ear.
"And that's going to confound our understanding of the difference between hearing loss that's caused by a viral infection or hearing loss caused by the usage of an ototoxic medication that's given for therapeutic reasons,” Stewart says.
Public health efforts to help slow the spread of the virus can also play a surprising role in hearing problems. Rush University's Michaelides has seen a number of patients in recent months who say their hearing has worsened since the start of the pandemic.
"It turns out that their hearing hasn't changed,” but their ability to communicate with others has, he says. And that's because so many Americans are wearing cloth face coverings when they're out in public. They're also standing farther away from each other to keep a safe distance.
"When you're wearing a mask, it muffles your voice and sometimes can make it harder for other people to hear” you, Michaelides points out. Masks also interfere with people's ability to pick up on visual cues when another person speaks. “For most people, it's not much of an issue. But in elderly patients who may already have some hearing loss, this can sometimes push them to the point where they're having difficulty understanding speech,” he adds.
As researchers continue to study the short- and long-term effects of a SARS-CoV-2 infection, experts say the public can expect to see more hearing-specific studies surface. In the meantime, if you experience worsening or sudden hearing loss, contact your doctor right away. Early treatment can prevent permanent damage in some instances, Michaelides says. Your doctor may also recommend tools, such as hearing aids, to improve your quality of life.
"There are a lot of patients that have been just getting by without hearing aids and decided now is the time” to get them, Michaelides says.