Follow the Brain Fog

At first, most people researching COVID-19 focused on the primary place the virus seemed to affect the body: the lungs. But over time, it became apparent that the virus could have lingering effects elsewhere in the body, too. “It took a while for those of us in the field to realize that this is a residual of the disease,” said Hajjar.

If these or other symptoms stick around more than four weeks after an acute infection, they are considered part of the constellation of issues that make up Long COVID. Some people with Long COVID experience cognitive symptoms; others may have fatigue, body aches, and respiratory, heart, and/or digestive challenges.

Even without COVID-19, cognitive dysfunction already has a disproportionate presence in the African American community, said Hajjar, who specializes in geriatrics and Alzheimer’s disease. Studies have found that African Americans are up to twice as likely to develop Alzheimer’s and related dementias as White people are.

Hajjar is interested in narrowing in on the connection between COVID-19 and these cognitive impairments. It is possible that the viral infection itself further increases the risk of long-term cognitive impairments for older African Americans. But he also wonders whether a COVID-19 diagnosis and symptoms have landed this higher-risk population in doctors’ offices more frequently and resulted in more of them being diagnosed with cognitive impairments.

A Comprehensive Plan

To work toward answering these and other questions, Hajjar, Goldstein, and their colleagues are currently recruiting more than 400 African Americans in Texas age 50 and older who report having been infected with COVID-19. Hajjar hopes to involve enough people in the study to allow the researchers to compare the characteristics of those with and without cognitive symptoms after a COVID-19 diagnosis, then to follow people over time to determine whether these symptoms resolve or progress.

Participants will visit the UT Southwestern campus for comprehensive cognitive testing at the beginning of the study, then after 6 months, 12 months, and 24 months. These tests will look at measures including memory, executive function, language, and visual and spatial processing, as well as monitoring mood and post-traumatic stress.

The study will also examine known risk factors for dementia, measuring the participants’ blood pressure, heart rate, blood vessel function, and immune system, as well as conducting brain imaging and genetic testing.

Researchers will use brain imaging and test participants’ blood and spinal fluid to look for two proteins, amyloid and tau, that are known to build up in the brains of people with Alzheimer’s disease. Some animal studies have suggested that these proteins may contribute to cognitive problems after a COVID-19 diagnosis. Hajjar and his colleagues want to learn more about whether people without a previous history of dementia or cognitive impairments have started to have a buildup of these proteins in their brains after being diagnosed with COVID-19. The team may also study newer biomarkers linked to Alzheimer’s and dementia to learn whether they play a role in brain fog.

Between participants’ in-person appointments, the researchers will conduct phone interviews to look for other factors that might affect participants’ health, from where participants live to their access to medical care, as well as their income and their perceived stress. The researchers will also ask participants about their experiences with racial discrimination, as recent research suggests that experiencing racism is linked to memory troubles and cognitive decline. “It’s a really very comprehensive evaluation,” said Goldstein. “We can look at how their outcomes related to cognition may relate to risk factors and predictors of good outcomes.”