No, Covid doesn’t cause Hearing Loss – Israeli Study confirms
It is known that the new Coronavirus affects most patients by at least temporarily wiping out two of their senses – smell and taste. There have been reports in the professional medical literature on possible hearing loss caused by the disease. But working in collaboration with the Galilee Medical Center in Safed, Tel Aviv University (TAU) researchers contradict these reports – they found no evidence of damage to the auditory system.
The study, just published in the journal Otology & Neurotology under the title “Auditory Performance in Recovered SARS-COV-2 Patients,” was led by Prof. Karen Avraham of TAU’s Sackler Faculty of Medicine, together with Dr. Amiel Dror and Dr. Eyal Sela of the Galilee Medical Center and the Azrieli Faculty of Medicine at Bar-Ilan University.
“Since the beginning of the pandemic,” Avraham explained, “it has been clear that COVID-19 has some long-term effects, such as the loss of the sense of smell and taste…While COVID-19 symptoms impact rhinology (anosmia, or the loss of the ability to detect one or more smells) and laryngology (airways), two major disciplines of the otolaryngology armamentarium, the virus has seemed to spare the auditory system. The possibility of hearing loss, however, has been debated among medical practitioners, with some reporting this symptom in recovered patients. The question is whether such hearing loss is caused by damage to the auditory system or whether it is a temporary symptom caused by fluids clogging the middle ear, as often happens in a common cold.”
The researchers began to investigate this question during the first wave of the pandemic, when the numbers of patients in Israel were still relatively small.
Participants included eight people without symptoms who had nevertheless tested positive for COVID-19 and eight healthy volunteers who served as a control group – all without any previous hearing loss. For the first time, the study provided quantitative measures for hearing quality following exposure to the virus.
“Our study checked whether COVID-19 can cause permanent neural or sensory damage to the hearing system and found no evidence for such damage,” noted Dror. “The study was wholly objective and quantitative. We used electrical data from the brainstem to test the entire route of soundwaves through the ear – tracking acoustic stimuli as they enter the auditory tube, hit the eardrum, make the ossicles vibrate and enter the cochlea until electric waves are ultimately received in the brain. We also examined the activity of the inner-ear hair cells that intensify and tune the sound and found no difference between the COVID-19-positive subjects and the control group.”
“It’s true that at this initial stage, the study examined asymptomatic patients,” said Avraham. “But objective scientific research takes a long time, and we started recruiting our volunteers in April, at the peak of the first wave of the pandemic in Israel. There are so many speculations about this virus and the damage inflicted by it, and we have shown that at least in the auditory system no damage was detected.” In a much more comprehensive continuing study, with hundreds of patients – including persons who had been severely ill and even ventilated, Avraham, Dror and Sela are currently trying to broaden the scope of their findings.
“It’s very important to base our knowledge of the virus upon objective studies and refrain from hasty conclusions,” said Dror. “The social media have attributed numerous illnesses and symptoms to the Coronavirus, but often the information is unfounded and leads to unwarranted stress, as well as needless pressure on the health system.”
“This study proposes that the COVID virus does not cause extensive neurological damage but is rather spotty, mostly affecting the sense of smell,” concluded Sela. “Moreover, the hearing impairment among some patients is mostly transient and secondary to fluid buildup in the middle ear, as for the common cold, and therefore likely passes once the acute disease is over.”
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