The COVID-19 infection causes many health complications such as blood clotting, inflammation, heart damage, chronic lung disease, neurological problems, and kidney dysfunction. A new study found that COVID-19 infection can also cause sudden hearing loss in patients.
In the study, the University of Manchester and NIHR Manchester Biomedical Research Centre (BRC) researchers collected data from previous 24 studies that found a link between COVID-19 and auditory problems.
The researchers observed that:
- 6 percent of COVID-19 patients suffered the sudden sensorineural hearing loss (hearing loss of 30 dB)
- 8 percent of patients had tinnitus (ringing or other noises in ears)
- 2 percent of patients reported vertigo (feeling of dizziness)
Possible reason for hearing loss post COVID-19
The exact cause behind the hearing loss, vertigo, and tinnitus after COVID-19 is unknown. But the researchers speculate that one possible cause of the hearing loss may be the mechanism by which the COVID-19 virus enters the body. The COVID-19 virus enters the body by invading fluid spaces or soft tissues of a part of the inner ear involved in the hearing called the cochlea or the cochlear nerve which carries auditory information from the cochlea to the brain. Both these conditions potentially lead to vertigo, tinnitus, and hearing loss.
The study also highlights the fact that some viral infections may cause hearing loss such as sequelae of cytomegalovirus, rubella, and measles. COVID-19 is linked to the neurological condition Guillain Barre Syndrome (GBS) which can cause a hearing disorder called auditory neuropathy spectrum disorder.
The researchers said that “There are multiple reports of audio-vestibular symptoms associated with COVID-19. However, there is a dearth of high-quality studies comparing COVID-19 cases and controls.” The researchers added “There is a need for high-quality studies that provide a comprehensive assessment of audio-vestibular function in COVID-19 and controls. This should include measures of impairment, hearing difficulty, and objective measures to identify the location of any dysfunction”.
Researcher Kevin Munro said that their team is currently monitoring hearing ability in patients hospitalized with COVID-19 and patients hospitalized due to other health issues. They will also try to determine the link between hearing loss and other factors such as lifestyle, other health conditions, and critical care interventions such as intubation.
