"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," Prof. Karen Avraham said.
In addition to the loss of smell, taste and touch, can COVID-19 also cause hearing loss?
Some of the professional literature has reported that it does.
However, according to a new study from Tel Aviv University, in collaboration with the Galilee Medical Center, these reports are wrong. Testing patients' hearing quality the researchers found no evidence of damage to the auditory system.
This research, published in the leading scientific journal Otology & Neurotology, was led by Prof. Karen Avraham of the Sackler Faculty of Medicine at Tel Aviv University, together with Dr. Amiel Dror and Dr. Eyal Sela of the Galilee Medical Center and the Azrieli Faculty of Medicine at Bar-Ilan University. Dr. Eyal Sela (left) and Dr. Amiel Dror (right). (Credit: Galilee Medical Center)
"Since the beginning of the pandemic, it has been clear that COVID-19 has some long-term effects, such as the loss of the sense of smell and taste," Avraham explained. "The possibility of hearing loss, however, has been debated among medical practitioners, with some reporting this symptom in recovered patients."
"The question," she continued, "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."Prof. Karen Avraham (Credit: TLV University)The researchers at TAU and the Galilee Medical Center 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 asymptomatic individuals who had tested positive for COVID-19 and eight healthy volunteers who served as a control group – all without any previous hearing loss. Entire ear scheme. (Credit: Dr. Amiel Dror)
For the first time, this 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," Dror explained. "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," Avraham explained. "It's true that at this initial stage, the study examined asymptomatic patients. 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," she said. "We have shown that at least in the auditory system, no damage was detected."
"It's very important to base our knowledge of the virus upon objective studies and refrain from hasty conclusions," Dror said. "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."
Sela, one of the senior authors of the study, added: "This study proposes that the COVID virus does not cause extensive neurological damage but is rather spotty, mostly affecting the sense of smell.
"Moreover, the hearing impairment among some patients is mostly transient and secondary to fluid buildup in the middle ear, as with the common cold, and therefore likely passes once the acute disease is over," he said.
