Could recovering from a COVID-19 infection leave a person more vulnerable to later dementia? Brain researchers are worried that COVID-19 infections could put survivors at higher risk for Parkinson disease, Alzheimer disease or other neurological complications.
On the Alert for Later Dementia After Recovery:
Previous research has shown that respiratory infections can have unexpected consequences for the nervous system. In certain vulnerable individuals, they can invade the brain, causing encephalopathy or, much later, dementia (Viruses, Dec. 20, 2019). Coronaviruses appear especially adept at this. They may damage nervous tissue directly or trigger harmful immune responses.
Although we may think of COVID-19 as a respiratory disease, up to two-thirds of patients show signs of injury in the central nervous system (Alzheimer’s Research & Therapy, Dec. 30, 2020). Some survivors have reported Bell’s palsy, confusion, forgetfulness, anxiety, sleep difficulties, depression and, in rare cases, psychosis. When people lose their sense of smell as an early symptom of COVID-19, the virus may be invading the brain from the nose. Neurologists worry that the infection may speed beta-amyloid accumulation, encouraging the development of plaques typical of Alzheimer disease.
A New Study Will Look for Cognitive Effects:
Some people have reported significant problems with forgetfulness or confusion after hospitalization with COVID-19. As a result of these concerns, scientists plan to study older individuals who have recovered (https://www.alz.org/research/for_researchers/partnerships/sars-cov2-global-brain-study). The goal is to see whether they are at higher risk for cognitive impairment. This international protocol aims to enroll 40,000 volunteers for long-term follow-up.
Inflammation in Response to SARS-CoV-2:
Autopsies of people who died from COVID-19 offer additional evidence of complications. Scientists who examined 13 brains found widespread vascular abnormalities in 10 of them (New England Journal of Medicine, Dec. 30, 2020). Although they did not detect SARS-CoV-2 in the brain tissue, they did see inflammation. Moreover, a study in mice indicates that a spike protein from the coronavirus is able to cross the blood-brain barrier and cause damage (Nature Neuroscience, Dec. 16, 2020). This might well hint at its potential to trigger later dementia.