Kevin Manro
Some viruses, such as measles, mumps, and meningitis, can cause hearing loss, but what about SARS-CoV-2, the virus that causes Covid-19?
In the first months of the pandemic, a rapid systematic review of Covid-19 and hearing impairment revealed a possible link between Covid-19 and hearing vestibular symptoms (deafness, tinnitus, dizziness). However, both the quantity and quality of early studies were low.
Now that the pandemic has been going on for over a year, more studies have been published, allowing researchers to estimate how common these symptoms are.
My colleagues and I identified about 60 studies reporting hearing vestibular problems in people with Covid-19 identified. An analysis of pooled data published in the International Journal of Audiology reveals that 7% to 15% of adults diagnosed with Covid-19 report voice vestibular symptoms. The most common symptom is tinnitus (tinnitus), followed by deafness and dizziness.
Tinnitus
Tinnitus is a common condition and affects about 17% of all adults. Most people with tinnitus also have deafness, suggesting a close relationship between the two. In fact, tinnitus is often the first warning that, for example, loud noises or exposure to toxic drugs to the ear has damaged the hearing system. Interestingly, there are reports that tinnitus is a common symptom of long-term Covid. This is where the symptoms appear weeks or months after the infection is gone.
The auditory organs are clearly very sensitive, as most people experience temporary tinnitus in a very quiet environment. There is also a strong link between tinnitus and stress. It is not uncommon to pay attention to the sound of the ears when people wake up at night and are stressed or anxious due to imminent deadlines, financial concerns, or bereavement.
This is usually less annoying once the sources of stress and anxiety have been removed. Surprisingly, hearing professionals rely on self-reporting because there are no clinical tests that can diagnose tinnitus.
It is unknown why tinnitus has been reported to people with confirmed Covid-19. The virus can attack and damage the auditory system. On the other hand, the psychological and emotional stress of a pandemic can be a trigger. However, care should be taken when interpreting these findings, as it is not always clear whether the study is reporting existing or new symptoms. What is lacking is a quality study comparing tinnitus with and without Covid-19.
Deafness and dizziness
Covid-19-related hearing impairments have been reported in a wide range of age groups and in Covid-19 severity, from mild (and managed at home) to severe (requiring hospitalization). There are several case reports of sudden hearing loss in one ear, often accompanied by tinnitus.
Sudden deafness occurs in about 20 people per 100,000 people each year. It is treated with steroids to reduce swelling and inflammation of the inner ear. However, treatment tends to work only if it is started shortly after the onset of deafness.
SARS-CoV-2 may be the cause of case reports of deafness in Covid patients, as the virus is known to cause sudden deafness. However, the number of cases of Covid-19 worldwide is so high that it is difficult to say for sure whether there are more cases of sudden deafness than we generally expect each year.
Another commonly reported symptom of Covid-19 is dizziness. It can be very difficult to distinguish this from vertigo, which is characteristic of damage to the balance system of the inner ear. However, the best estimate is that vertigo occurs in about 7% of Covid-19 cases.
The beginning of our understanding
Given the importance of providing timely evidence to inform healthcare services, information from this new systematic review is welcome, but so far the evidence has been in investigations and case reports. Is based. Given the high proportion of Covid-19 in the population, it is important not to diagnose in the absence or chance of auditory vestibular symptoms.
However, the results of the review may simply reflect the beginning of an understanding of this urgent health condition.
What is lacking is a carefully conducted clinical and diagnostic study comparing a sample of people tested positive for Covid-19 with a sample of a non-Covid control. To that end, we are leading a year-long study to investigate the long-term effects of Covid-19 on the auditory vestibular system of people who have previously been hospitalized for the virus.