الفهرس 
COVID-19 PATHOGENESISOnly 14 pages are availabe for public view
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Abstract
Background: Coronavirus disease 2019 (COVID-19) is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection. The origin of COVID-19 was reported in December 2019 in Wuhan, China, where cases of unknown pneumonia were reported. A novel coronavirus was obtained from these cases and was suggested as the cause of this outbreak.
Aim of the Work: To detect presence or absence of auditory dysfunction and its type in COVID-19 patients. To investigate the possible site of lesion (up to the level of brain stem) in relation to COVID-19 infection.
Materials and Methods: The present study was conducted on a total of forty-five subjects in Audiology Unit-Ain Shams University Specialized Hospital and El-Demerdash hospital after approval of research Ethics Committee in September 2021, FWA 000017585. The purpose and design of the study were explained to all participants individually and informed oral consent was taken before starting the examination.
Results: The present study was conducted to detect presence or absence of auditory dysfunction in COVID-19 patients and to investigate the possible site of lesion (up to the level of brain stem) in relation to COVID-19 infection. The study was performed on two groups: a study group consisted of 30 post COVID-19 patients with mean age of 34.80 + 9.81 years and a control group consisted of 15 normal hearing individuals without previous history of COVID-19 infection, their mean age was 32.80 + 8.28 years. Both study and control groups underwent basic audiological assessment (PTA, acoustic immitancemetry & acoustic reflex), TEOAEs in presence and absence of contralateral suppression, Arabic speech intelligibility in noise test (SPIN) for adults and neuro-otologic ABR. In the present study, Pure tone audiometry showed normal hearing in 28 (93.3 %) subjects of the study group subjects and documented mild high frequency sensorineural hearing loss in 2 (6.7%) subjects. Speech audiometry showed normal speech reception threshold and excellent speech discrimination in all subjects. Although the average of all frequencies was found within the normal limits in the hearing assessment of patients by PTA performed in patients who had COVID-19 and recovered, a significant higher thresholds was found, especially at 2, 4 and 8 KHz in comparison to the control group, no significant difference between the study and control groups as regards SPIN test, Also there was significant lower (worse) TEOAEs signal to noise ratio (SNR) values at (2.8 and 4 KHz) in the study group in comparison to the control group and no significant difference between the study and control groups as regards low repetition rate & high repetition rate ABR parameters. In our study, thirty ears in the control group and sixty ears in the study group were compared. It was found that 76.7% of the ears of the control group and 42.4% of the ears of the patient group had normal suppression and there was a significant relationship between the two groups.
Conclusion: OAEs have become a more frequently used method to measure injury to outer hair cells and seem to be a highly sensitive method to cochlear insult. OAEs suppression is an important clinical instrument for detecting central auditory system inhibitory efferent role on cochlear processes that play a critical task in speech perception and our study revealed that the efferent system could be affected in COVID 19 patients.