COVID‐19 and cognitive impairment: A cross‐sectional clinic‐based study

Patients with dementia are more prone to acquire COVID‐19 infection. Patients with COVID‐19 showed a tendency to develop cognitive impairment.


INTRODUCTION
The SARS-CoV-2 virus causes Corona virus Disease . The majority of those infected with the virus will have mild to moderate respiratory symptoms and will recover without the need for specific treatment. Some, on the other hand, will become gravely unwell and require medical attention. People over the age of 65, as well as those with underlying medical disorders such as cardiovascular disease, diabetes, chronic respiratory disease, or cancer, are more likely to develop serious illnesses. COVID-19 can make anyone sick, and they can get seriously ill or die at any age (https://www.who.int/healthtopics/coronavirus#tab=tab_1).
Dementia is a syndrome that causes cognitive function (i.e., the ability to process thoughts) to deteriorate beyond what would be expected from biological aging. Memory, thought, orientation, comprehension, computation, learning capacity, language, and judgment are all affected. The ability to think is unaffected. Changes in mood, emotional control, behavior, or motivation are frequently accompanied by, and sometimes preceded by, impairment in cognitive performance (https: //www.who.int/news-room/fact-sheets/detail/dementia). Dementia can be caused by a number of diseases and injuries that damage the brain either directly or indirectly, such as Alzheimer's disease or stroke (https://www.who.int/news-room/fact-sheets/detail/ dementia).
Dementia is the sixth greatest cause of death worldwide, and one of the top causes of impairment and dependency among the elderly.
Dementia has medical, psychological, social, and economic consequences for people with dementia, as well as their caregivers, families, and society in general. Dementia is widely misunderstood and stigmatized, leading in delays in diagnosis and treatment (https://www.who. int/news-room/fact-sheets/detail/dementia).
Dementia has become much more common in recent decades around the world. Over 50 million individuals worldwide suffer from dementia, with that number expected to rise to 152 million by 2050 (Alzheimer's Association Report: 2019 Alzheimer's disease facts and figures). People with dementia have become the most vulnerable population due to aging, weakness, reduced autonomy, chronic immunological disorders (Rogers et al., 2017), and other chronic diseases, particularly comorbidities of vascular diseases (Nikolich-Zugich et al., 2020). Patients with dementia are sensitive to viral infections such respiratory syncytial virus disease, severe acute respiratory syndrome coronavirus, and influenza A, according to epidemiological research (Azarpazhooh et al., 2020). Their postinfection clinical result is worse than the normal population (Killen et al., 2020;Iaboni et al., 2020).
The incidence of seizures, psychosis, and memory issues among Covid-19 patients is yet unknown. According to some research, up to 84% of individuals with acute Covid-19 recover with mental disorientation and abrupt mood fluctuations. Even if the true rate of long-term brain damage is lower, because so many people have been infected, the number of people with long-term cognitive impairments will be significant (Covid-19 may result in brain damage and increase the risk of dementia). In this study, we aimed to study the clinical manifestations of COVID-19 infection among Sudanese demented patients and the prevalence of cognitive impairment among Sudanese nondemented patients. 3. History of diabetes mellitus, hypertension, ischemic heart disease, renal diseases, and malignancy.

METHODS AND MATERIALS
4. Symptoms in favor of involvement of: -Respiratory system: cough, breathlessness.
-CNS: convulsion, weakness of upper and lower limbs.

DISCUSSION
Dementia is a clinical syndrome characterized by memory disturbance and cognitive impairment. Vascular dementia is the commonest cause, followed by Alzheimer's disease, senile dementia, presenile dementia, and posttraumatic dementia. Rare causes include Huntington chorea, Lewy's body dementia, frontotemporal dementia, and advanced stage of Parkinson's disease (Hugo & Ganguli, 2014). Dementia is associated also with advanced age, hypertension, diabetes and Ischemic heart disease. Patients with dementia are more prone to develop COVID-19 infection twice more than dementia patients (Livingston et al., 2020).
There are many hypotheses that can explain the increased incidence of COVID-19 infection among dementia patients, one of these is that patients with dementia cannot stick to the preventive measures that can minimize spread of COVID-19 infection like wearing masks, frequent washing of hands and social distancing. The second hypothesis is that patients with dementia, especially vascular dementia, tend to have damage to the blood brain barrier so they become more vulnerable to infection (e.g., bacteria, fungal, and viral infections) that can spread to the brain (Hardan et al., 2021;Ryoo et al., 2020). Patients with dementia who have COVID-19 infection will have a chance to experience a severe form of the disease more than nondemented patients; this due to the fact that dementia is associated with diabetes, hypertension and ischemic heart disease. All these factors increase morbidity and mortality among patients with COVID-19 Infection (Matias-Guiu et al., 2020).
Hypoxia, superadded brain infection, drugs used with anesthesia and damage to the blood brain barrier all these factors can increase mortality among demented patients who developed COVID-19 infection (Fuh & Yang, 2015).
Regarding the second group, cognitive function was assessed using well-validated semistructured neuropsychiatric measures. We tend to see the patients who were referred from the isolation centers monthly for six months. All of them were adult Sudanese patients, they had no history of dementia, they were speaking Arabic fluently and the test for COVID-19 antibodies was positive. The common cognitive function impairments, which were noticed were as follows: memory recall, memory recognition, memory encoding, followed by executive functioning and processing speed and a considerable number of patients had category fluency and phonetic fluency impairment. At the end of this study questions were raised regarding the second group: Are these cognitive impairments transient or will they be permanent? Will those patients end with a full bloom picture of dementia in the future? Does the ongoing COVID-19 pandemic cause a significant increase in the number of dementia patients in the long term? Does COVID-19 pandemic increase numbers of patients with dementia and Alzheimer's disease worldwide?
So we need more studies to know the long-term impact of COVID-19 on the brain's health.