Since the global pandemic was declared on January 30, 2020, scientists have been learning more about the unusual and unexpected symptoms associated with COVID-19. One of the most perplexing is the virus’ effect on hearing.
Below is a look at two recent studies on the topic.
How Hearing Loss Relates to Viral Infections 
There are a number of viruses that can cause hearing loss. Some damage the inner ear structure, cause inflammation or increase susceptibility of bacterial or fungal infection.
Most cases of hearing loss related to a virus are categorized as sensorineural, although there are some cases of conductive or mixed hearing loss developing with certain viruses such as HIV.
Asymptomatic Covid-19 Cases and Hearing Loss
Published in the May-June issue of the American Journal of Otolaryngology, this study looked at the hearing of 20 participants with confirmed cases of coronavirus who had none of the telltale symptoms:
- Fever
- Cough
- Fatigue
- Gastrointestinal infection
Participants were between 20 to 50 years of age with no history of hearing loss. Twenty healthy subjects with normal hearing were used as controls.
Both groups underwent a series of tests, including:
- Ear exam
- Audiological evaluation
- Immittance evaluation
- Transient evoked otoacoustic emissions
The results of the study indicated that high frequency pure-tone thresholds as well as the transient evoked otoacoustic emissions were significantly worse in the test group as compared to the controls. This study suggests that COVID-19 has a negative effect on the hair cells within the cochlea. In addition, the absence of symptoms does not keep your ears safe from harm.
Presence of COVID-19 in the Middle Ear
A study published online with JAMA Otolaryngology – Head & Neck Surgery in June looked at the presence of the virus in the middle ear.
This small study contained only three patients, all tested positive for COVID-19 and presented with symptoms. Specimens were collected from their middle ears using cytobrush swabs. The researchers found that 2/3 of the participants’ samples tested positive for the virus.
The results have significant implications for otolaryngology procedures. While procedures are in place to protect providers from droplets from the nose, mouth and airway from infected individuals, there is nothing in place in regard to elective ear surgery.
While both of these studies are limited by their sample size, the results indicate that COVID-19 may affect the ears, possibly leading to hearing loss.
To learn more about protecting your hearing or to schedule an appointment with an audiologist, contact the experts at Houston Hearing Center.
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