More reason to do everything we can to protect older adults from COVID infection: new studies show an association between COVID-19 and memory problems and worse physical health eight months after diagnosis and others finding cognitive decline and accelerated Alzheimer’s disease symptoms as long as 6 months after infection.
Memory problems, lack of energy, worse physical health
A study from the University of Oslo published in JAMA Network Open involved 9,705 non-hospitalized adults in Norway who had been either tested for SARS-CoV-2 at four large labs or randomly selected (untested).
At that time, nearly all COVID-19 testing in Norway was in symptomatic patients. After an average follow-up of 257 days after a baseline survey, 72 of the 651 COVID-19–positive respondents (11%) said they had memory problems, compared with only 254 of 5,712 (4%) of those who tested negative for infection and 80 of 3,342 untested participants (2%).
A multiple logistic regression model showed that SARS-CoV-2 positivity at baseline was strongly linked to memory deficits at 8 months follow-up, compared with the untested group (odds ratio, 4.66). In addition, 267 of 649 participants (41%) in the COVID-19–positive group reported that their health had substantially deteriorated over the previous year, and 59 of the 267 (82%) who reported memory impairment also said their health had worsened.
Eighty-one of 651 positive respondents (12%) said they had difficulty concentrating. Similar numbers of patients in the three different groups reported depression, lack of energy, and pain.
Low oxygen, persistent cognitive deficits
New research presented at the Alzheimer’s Association International Conference (AAIC) tied COVID-19 to persistent cognitive deficits, including the acceleration of Alzheimer’s disease signs and symptoms. One study followed cognitive abilities and sense of smell in nearly 300 older adult Amerindians in Argentina 3 to 6 months after SARS-CoV-2 infection.
More than half had lingering forgetfulness, and about one quarter had problems with language and executive function, all of which were tied to persistent loss of smell but not to the severity of infection. In another study, researchers analyzed the plasma samples of 310 older hospitalized COVID-19 patients in New York, 158 of whom had neurologic symptoms.
The most common symptom was confusion owing to toxic-metabolite encephalopathy (TME), global cerebral dysfunction common among very ill patients, regardless of the cause. Patients without cognitive problems at baseline, with and without coronavirus-related TME, had higher levels of certain proteins associated with Alzheimer’s disease and inflammatory markers such as C-reactive protein, which the researchers said could signify a breach of the blood-brain barrier and neural or glial injury.
A study of 32 COVID-19 patients 2 months after release from the hospital revealed that 56.2% had cognitive limitations, including problems with short-term memory.*
Dr. Melvin Sanicas (@Vaccinologist) is a physician-scientist specializing in vaccines, infectious diseases, and global health.