This study shows the prevalence of neurological manifestations in 105 (22.02%) hospitalized patients with COVID-19. CNS failure was the main form of neurological symptoms in these patients. Neurological manifestations of patients with COVID-19 have been reported to be 36.4% in China and 57.4% in Europe[20,21]. CT findings of the brain of most COVID-19 patients, particularly those with severe respiratory failure, have indicated cerebral hemisphere infarction or matter abnormalities and acute cerebrovascular disease, including intracranial hemorrhage, large-vessel occlusion, and acute or subacute ischemic stroke. In our study, cerebrovascular disease and impaired consciousness were predominantly the most common neurological manifestations observed in the patients who were referred to the hospital as an emergency case with decreased level of consciousness and often with unusual symptoms of COVID-19, including fever and cough. Their pulmonary lesions were found by immediate lung CT. Besides, using a positive RT-PCR detection, the patients were diagnosed as having COVID-19. Laboratory findings have also demonstrated that the mean lymphocyte level in patients was slightly lower, and neutrophils were higher than normal, suggestive of an immune response, especially T cells, to the virus. Similarly, American Thoracic Society guidelines for community-acquired pneumonia has reported that nervous system disorders are significantly more frequent in severe than non-severe infections (45.5% vs. 30.2%). The highest frequency of neurological manifestations was detected in COVID-19 patients with severe respiratory failure disease, acute cerebrovascular disease (5.7%), impaired consciousness (14.8%), and skeletal muscle injury (19.3%). Cerebrovascular disease and impaired consciousness were acute and asymptomatic in the early stages of the disease (median time: 1-2 days). Based on laboratory findings, patients with severe compared to no-severe respiratory infection displayed higher inflammatory responses, including high white blood cells and neutrophil counts, lower lymphocyte counts, and increased levels of C-reactive protein compared to patients. In the present study, ischemic stroke, decreased consciousness, and headache were the most frequent reported neurological symptoms, with the rates of 34 (7.13%), 28 (5.88%), and 13 (2.72%), respectively. However, GBS and encephalitis, with the rates of 2 (0.42%) and 5 (1.05%), respectively, were uncommon. In a number of former investigations, acute ischemic strokes occurred in 31% of 108 COVID-19 hospitalized patients, and 3 out of 15 patients with neurological manifestations had stroke and GBS the least.[23-25]. In an observational study of 219 COVID-19 patients with cerebrovascular disease, 10 (4.6%) patients had acute ischemic stroke, and only one (0.5%) suffered from cerebral hemorrhage. However, in another investigation on 214 COVID-19 patients in Wuhan of China, headaches (17%) and dizziness (13%) were the highest CNS symptoms, but cerebrovascular (0.3%) and seizures (0.5%) were the lowest. These results were slightly different from those of our study. In a study of neurological symptoms in patients with COVID-19, the most common neurological symptom was headache[27,28]. Claudio et al. have reported 103 patients hospitalized with SARS-CoV-2 infection, and 91.3% cases indicated at least one neurological disorder. Besides, sleep disturbance was the most common symptom, followed by dysgeusia, headache, hyposmia, and depression. In the study by Eric et al., the most frequent neurological signs included myalgia (228; 44.8%), headache (192; 37.7%), encephalopathy (162; 31.8%), dizziness (151; 29.7%), dysgeusia (81; 15.9%), and anosmia (58; 11.4%). In the study of David et al. on 576 patients with COVID-19, 130 (22.6%) patients complained of headache. Following our study, similar surveys conducted on the frequency of neurological disorders associated with COVID-19 were acute ischemic stroke, GBS[33,34] , intracranial hemorrhage, encephalitis[36,37] , multiple sclerosis, and altered consciousness.
The present study reported the prevalence of CNS disorders among age groups and found that the neurological symptoms are uncommon in patients below 30 years of age, but higher in cases over 60 years. Moreover, 54 patients were male. Similar studies have reported different results. For instance, Wu et al., according to a recent report by the China Centers for Disease Control and Prevention, reported a total of 965 infected patients under the age of 19 nationwide. Carlos et al. displayed that the majority of patients had a mean age of 66.4 years, and 56.2% of cases were male, which supports our study. In Moran et al. survey, 53.6% of patients was male, and their median age was 42 years old. In this regard, different studies have reported varied mean age in relation to neurological symptoms, e.g. ischemic stroke, Encephalitis, and intracranial hemorrhage (with 65.6, 45, and 38 years of age, respectively). In our study, the mortality rate of patients with and without neurological symptoms were 30.4% and 19.62%, respectively. In a research work on 814 patients admitted to the hospital with confirmed SARS-CoV-2 infection, 329 (39.1%) had severe neurologic complications, of which 4.1% died. In another work, there were 48 (27.6%) deaths, of which 22 were attributed to COVID-19 and 26 to stroke.indicating that the effect of the virus on the brain is greater and needs further investigation. A limitation of our study was mainly the small number of patients studied. Due to the prevalence of coronavirus, we were unable to have a direct communication with infected patients and reviewed only the records of hospitalized patients. Furthermore, some diagnostic methods, such as lumbar puncture and CSF examination, were performed to prevent the transmission of disease. For future studies, we propose more examples of patients with neurological symptoms in different populations. Moreover, we recommend the investigation of genetic differences and the role of the genome in response of patients to COVID-19. More research is required to investigate whether neurological symptoms occur as a direct effect of the virus on the brain or on other organs.