Via The Conversation, an article by Professor John F. Connolly of McMaster University: Coronavirus and the brain: Diagnosing and treating COVID-19's neurological effects. Excerpt:
As the number of COVID-19 patient records grows, researchers are meticulously combing through the data, searching for a better understanding of the virus and what we can expect in the months and years ahead. What is now of increasing concern in health care is the realization that the virus can not only be severe, but can also have long-term consequences.
Respiratory and skeletal muscle consequences surfaced earlier in the pandemic. More recently, the neurological and neurocognitive aspects of the virus have become a major concern. The neurocognitive symptoms linked to coronaviruses, counting COVID-19, include delirium, both acute and chronic attention and memory deficits linked to hippocampal and cortical damage, as well as learning deficits in both adults and children.
These symptoms feature significantly in a large percentage of COVID-19 patients. In March, a study reported 36.4 per cent of COVID-19 patients have neurological symptoms, including headache, disturbed consciousness and paresthesia (a burning or prickling sensation in parts of the body such as hands, legs and feet). Not surprisingly, severely affected patients are more likely to develop neurological symptoms than patients who have mild or moderate disease.
More recently, a report published in early June in the New England Journal of Medicine reported that 84 per cent of the patient sample had neurologic symptoms. Also, a recent paper in the Lancet using autopsy reports on patients who had severe cases noted brain tissue edema (a life-threatening condition that causes fluid to develop in the brain, causing pressure inside the skull) and neuronal degeneration (when a brain’s neurons break down, lose connectivity and affect brain function).
Assessing neurological symptoms
The percentage of COVID-19 patients with neurological symptoms varies greatly between studies. One of the reasons is inconsistent assessment methods. Research has shown behavioural assessment (testing based on things like the patient’s visual responses, motor function and communication) is frequently inaccurate.
Reliable neurocognitive assessment procedures will be essential both in accurately assessing active and post-COVID patients’ cognitive abilities, and in tracking their recovery. Objective assessments of brain function can help pinpoint when neurocognitive symptoms begin to appear in COVID-19 patients, which patient groups are at a higher risk, how long neurological effects may last and what treatments are most effective. In the early stages of understanding COVID-19 and researching the neurological effects, definitive facts around these issues remain unknown.
