How COVID-19 Affects Hearing and Balance
By now, you’re probably familiar with the range of symptoms induced by the SARS-CoV-2 virus, a disease we call COVID-19. Most commonly, people with COVID-19 have reported symptoms such as fever, a dry cough, headache, shortness of breath, and diarrhea. Other frequently reported symptoms include chills, fatigue, body aches, sore throat, and nausea.
The effects of COVID-19 can range from mild or even asymptomatic, to severe and fatal. As researchers come to understand more about this relatively new virus (which seems to be ever mutating), the assault of COVID-19 on our senses is also becoming more apparent. Loss of taste and smell, and blurred vision have all been reported suggesting that the SARS-CoV-2 virus is able to infect the central nervous system. It’s through this route that researchers suspect COVID-19 is also able to affect our hearing and balance.
COVID’s Assault on Our Ears
Multiple studies have now established an association between COVID-19 and hearing loss, ranging from a mild to profound sensorineural hearing impairment. There is also an increasing amount of evidence that COVID-19 is related to the onset of tinnitus. In addition to this, dizziness and vertigo, which are considered dysfunctions of the vestibular system, have also been reported following COVID-19 infection.
Although different studies will naturally come to slightly different conclusions, the prevalence of vestibular issues from COVID-19 appears to be just over 30% of cases, which include occasions of dizziness, vertigo, and unsteadiness. Dizziness is becoming increasingly recognized as a persistent symptom even months after infection.
New onset hearing loss is reported in around 7% of those with COVID-19, with most of these cases being a mild loss. While the majority pf people spontaneously recover their hearing function within a few weeks after infection, a small percentage (less than 2%) of hearing loss and tinnitus as a result of COVID-19 have been found to persist to at least 6 months after the illness.
It should also be mentioned that some medications used to treat a COVID-19 infection can be ototoxic, meaning they can damage the ear, causing tinnitus or hearing loss. These antiviral drugs can include quinine, chloroquine, and hydroxychloroquine.
How Does the Virus Get In?
COVID-19 is known as a respiratory disease, meaning the virus affects the organs of the respiratory system, including the lungs, nose, mouth, throat, and airways. However, unless all the anatomy books in the world are confused, the ears are not part of the respiratory system, are they?
Our hearing, taste, sense of balance, and sight, are all controlled through the central nervous system. The fact that these senses and functions can be knocked out by a COVID-19 infection suggests that the virus is able to access the nerves that lead to and from our sensory organs.
In order to test the theory that COVID-19 has the potential to directly cause hearing loss and dizziness, researchers studied the cells of human and animal inner ear tissues. For the virus to be able to lock onto a cell and invade it, the cell must contain certain proteins or receptors on its surface. And unfortunately for our hearing and balance, researchers have found that the hair cells of our inner ears proudly display these SARS-CoV-2-attracting receptors.
So, do COVID-19 virus particles just float into your ear canal and infect those unsuspecting inner ear hair cells? This route of entry is less likely than the virus entering through the nose or mouth, and traveling through the Eustachian tube, which adjoins the nose to the middle ear. Alternatively, virus particles may enter through the nose, gain entry into the olfactory nerve (the nerve controlling the sense of smell), and from there, make its way into the central nervous system, and eventually find itself in the auditory nerve (for hearing) or vestibular nerve (for balance). Sneaky little buggers.
Help, the World is Spinning
Fortunately, most cases of COVID-19-related hearing loss or vestibular symptoms have been temporary, self-resolving without treatment within a fortnight after infection. Some cases of hearing or vestibular symptoms have been treated with steroid medications, though such treatment doesn’t appear to guarantee full or faster recovery compared to allowing the body to recover alone.
If you’re suffering from dizziness, vertigo, tinnitus, or hearing loss during or after experiencing COVID-19, rest assured that it will most likely resolve on its own once the infection passes. However, if you’re one of the unlucky ones who find the world still spinning or buzzing several weeks after you’ve defeated SARS-CoV-2, you may want to visit your physician. Treatments or at least management strategies exist for these irritating, and sometimes debilitating, conditions. You may be prescribed medications, taught certain coping strategies, or recommended a hearing aid to help with tinnitus or hearing impairment.
COVID-19 has also been associated with sudden sensorineural hearing loss, a condition where your hearing deteriorates rapidly within 72 hours. As the best chance of recovering your hearing after sudden sensorineural hearing loss is achieved with high dose steroids within 3 days, don’t wait for the 2 weeks post-infection to see if it’ll self-resolve – see your physician immediately.
Hearing loss and dizziness are relatively newly recognized symptoms of COVID-19. More research and information are needed before we can fully understand how it all works and how to best approach these symptoms when they arise.