COVID-19 is associated with worsening cognitive function and acceleration of Alzheimer's disease pathology


New research reported at the 2021 Alzheimer's Association International Conference (AAIC) has found that older people are more likely to experience worsening cognitive function after COVID-19 infection. People with COVID who experience neurological symptoms also have higher levels of Alzheimer's disease-associated proteins in their blood, suggesting an acceleration of Alzheimer's disease pathology.

Initial findings presented by Dr Gabriel de Erausquin of the University of Texas Health Science Center showed that older Amerindians from Argentina experienced persistent problems with forgetfulness, language and executive function months after recovery from COVID-19.  As part of the Alzheimer's Association-led global SARS-CoV2 consortium, Dr de Erausquin evaluated a cohort of almost 300 older adult Amerindians between 3 and 6 months after COVID-19 infection, over 50% of whom experienced cognitive symptoms. People with worsening cognitive function also tended to have anosmia (problems with the sense of smell).  

Prof. Thomas Wisniewski of the New York University Grossman School of Medicine reported the results of a study evaluating the presence of Alzheimer's disease-associated proteins such as Tau, amyloid-beta and neurofilament light chain in plasma samples from COVID-19 patients admitted to hospital. Comparing a group of 158 patients who experienced neurological symptoms (such as confusion) with patients who did not experience these symptoms, the researchers found higher levels of these proteins in their blood, suggesting an acceleration of Alzheimer's disease pathology.

A team of researchers in Greece led by Dr George Vavougios studied a group of previously hospitalised COVID-19 patients for two months after discharge. Similar to the study of Argentinian Amerindians, over 50% of the 32 patients studied experienced cognitive decline in the months after recovery from COVID-19. People who were older and with higher waist circumference experienced more severe cognitive symptoms, associated with lower levels of oxygen saturation in the blood.  

Dr Heather Snyder, Vice President of Medical and Scientific Relations at the Alzheimer's Association, called for more research on how COVID-19 infection affects cognition, stating: "These new data point to disturbing trends showing COVID-19 infections leading to lasting cognitive impairment and even Alzheimer's symptoms. With more than 190 million cases and 4 million deaths worldwide, COVID-19 has devastated the entire world. It is imperative that we continue to study what this virus is doing to our bodies and brains."