Cranial Nerve Impairment Associated With COVID-19 Infections: A Systematic Review

The COVID-19 pandemic has created huge economic and healthcare burdens. In most cases, the virus affects the lungs and causes respiratory symptoms. Additionally, its impact on the cranial nerves remains unclear. We thus aimed to investigate cranial nerve dysfunction in patients with COVID-19 infection. We conducted a systematic literature search of relevant and eligible literature in five databases: PubMed, Web of Science, Medline, EBSCO, and Google Scholar. Our sample included 21 case reports, one case series with 29 patients, and one analytical study with 135 cases. Participant ages ranged from 23 months to 72 years (mean age of 47.5 ± 19.02). The mean time from respiratory symptoms to the onset of neurological signs was (9.6 ± 7.4) days, and the mean recovery time was (16.3 ± 15.3) days. Cranial nerve impairment associated with COVID-19 infection has affected a large population, from infants to the elderly. Facial and abducent nerves were the most commonly affected cranial nerves with reported good prognosis or complete recovery within a few days to weeks. Olfactory dysfunctions were widely detected among COVID-19 patients.