Adults who reported worsening memory or concentration following SARS-CoV-2 infection showed no objective cognitive deficits on standardized neuropsychological testing compared to those without such complaints, according to research published online October 27 in the Journal of Psychiatric Research.
Cognitive Testing Results Versus Patient Complaints
Researchers evaluated 32 adults with self-reported worsening memory or concentration post-infection and 34 control individuals who reported no such changes. Participants were assessed more than 12 weeks after contracting the virus. The study excluded individuals with a history of COVID-related hospitalization, Axis I psychiatric diagnoses, head injury, neurological disorders, or positive urine toxicology screenings.
A total of 62 participants completed neuropsychological testing through the MATRICS Consensus Cognitive Battery and the California Verbal Learning Test-Third Edition. When scores were condensed into a single objective cognition factor, the cases and control individuals did not differ significantly in their cognitive performance.
Participants Reporting Cognitive Decline Score Higher on Psychological Measures
While objective tests showed no deficits, participants reporting cognitive decline scored significantly higher on psychological and biological measures. Cases scored substantially higher on the Beck Depression Inventory Cognitive-Affective subscale, with a mean score of 5.53 compared to 1.35 for controls. They also scored higher on the Beck Anxiety Inventory, registering a mean score of 12.06 against 2.38 for the control group.
Biological analysis revealed that 41% of the cases carried the apolipoprotein E (APOE) epsilon 4 allele, compared to 6% of the control group. Cases also exhibited elevated levels of soluble CD14, an inflammation marker. In the final statistical models, depression scores and APOE epsilon 4 status emerged as significant independent predictors of subjective complaints, whereas objective cognition and inflammation levels did not.
Context of Brain Fog in Long COVID
Brain fog remains a frequently reported feature of long COVID, defined by the Centers for Disease Control and Prevention as symptoms persisting weeks or months after an initial infection. Durga Roy, M.D., with the Johns Hopkins School of Medicine, noted during a session at the American Psychiatric Association’s Annual Meeting that fatigue and cognitive impairment are the most debilitating symptoms of long COVID, potentially compounded by associated anxiety and depression.
Other conditions similarly trigger brain fog, including cancer therapies, fibromyalgia, chronic fatigue syndrome, and lupus. Jon Levenson, M.D., with Columbia University Irving Medical Center, explained during the same meeting that up to 75% of people undergoing cancer treatment experience cognitive decline, with about 35% experiencing cognitive decline months or years later.
Frequently Asked Questions About Post-COVID Cognitive Complaints
Do standard cognitive tests always detect post-COVID brain fog?
Not necessarily. Research published in the Journal of Psychiatric Research demonstrated that adults reporting memory or concentration declines after SARS-CoV-2 infection performed similarly to control groups on standardized neuropsychological tests.
What factors independently predicted subjective cognitive decline in the study?
Depression scores and the presence of the APOE epsilon 4 allele served as significant independent predictors of self-reported cognitive issues in final regression models.
What treatments are currently discussed for long COVID brain fog?
Potential interventions for brain fog include cognitive-behavioral therapy, graded exercise therapy, and cognitive rehabilitation provided by neuropsychologists, occupational therapists, and speech therapists.
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