Have you seen those Facebook posts which ask if you personally know anyone who’s had COVID? Is that a 2020 question, or what? And it’s now apparent that many survivors of COVID-19 have neurological symptoms. As we know, these symptoms include a loss of smell, delirium and an increased risk of stroke. But there are also longer-lasting consequences for the brain, including myalgic encephalomyelitis/chronic fatigue syndrome and Guillain-Barre syndrome, reports Considerable’s article entitled “Does COVID-19 increase your risk of memory loss? Here’s what we know.”
The article say that these effects may be caused by direct viral infection of brain tissue. However, there is growing evidence to suggest that additional indirect actions triggered via the virus’s infection of epithelial cells and the cardiovascular system, or through the immune system and inflammation, contribute to lasting neurological changes after contraction of COVID-19. Scientists are looking at whether there be a COVID-19-related wave of memory deficits, cognitive decline and dementia cases in the future.
Scientists say that many of the symptoms we link to an infection are, in fact, due to the protective responses of the immune system. This is also true when it comes to feeling sick: the general malaise, tiredness, fever and social withdrawal are caused by activation of specialized immune cells in the brain, called neuroimmune cells, and signals in the brain.
In addition to changing behavior and regulating physiological responses during illness, the specialized immune system in the brain also has several other roles.
Research now shows that the neuroimmune cells that are at the connections between brain cells (synapses), which provide energy and minute quantities of inflammatory signals, are essential for normal memory formation. Unfortunately, this also is a way in which an illness like COVID-19 can cause both acute neurological symptoms and long-lasting issues in the brain.
During illness and inflammation, the specialized immune cells in the brain become activated, sending out large amounts of inflammatory signals and changing how they communicate with neurons. Because COVID-19 involves a massive release of inflammatory signals, there are both short-term effects on cognition (delirium) and the potential for long-lasting changes in memory, attention and cognition.
(And my personal, non-legal advice? Take your Vitamin D3!)
There is also an increased risk for cognitive decline and dementia, including Alzheimer’s disease, during aging.
The potential connection between COVID-19 and persistent effects on memory are evidenced by observations of other illnesses, such as patients who recover from a heart attack or bypass surgery who report lasting cognitive deficits that become exaggerated during aging.
It will be many years before we know whether the COVID-19 infection causes an increased risk for cognitive decline or Alzheimer’s disease. However, this risk may be reduced by prevention and treatment of COVID-19. Prevention and treatment both rely on the ability to decrease the severity and duration of illness and inflammation. Interestingly, new research suggests that common vaccines, including the flu shot and pneumonia vaccines, may reduce the risk for Alzheimer’s. Several emerging treatments for COVID-19 are drugs also suppress excessive immune activation and inflammatory state. These treatments may also reduce the impact of inflammation on the brain and decrease the impact on long-term brain health.
Reference: Considerable (Aug. 7, 2020) “Does COVID-19 increase your risk of memory loss? Here’s what we know”
