Background
This study describes neuropsychological, medical, psychiatric and functional correlates of cognitive complaints experienced after recovery from acute COVID-19 infection.
Methods
Sixty participants underwent neuropsychological (NP), psychiatric, medical, functional, and quality of life assessments 6-8 months after acute COVID-19. Those seeking care cognitive complaints in a post-COVID-19 clinical program for Post-Acute Symptoms of COVID-19 (PASC) (Clinical Group, N=32) were compared to those recruited from the community who were not seeking care (Non-Clinical, N=28). A subset of participants underwent serological testing for pro-inflammatory cytokines C-Reactive Protein, Interleukin-6, and Tumor Necrosis Factor-α in order to explore correlations with neuropsychological, psychiatric and medical variables.
Outcome
For the entire sample, 16 (27%) had extremely low test scores (< 2
nd
%ile on at least 1 NP test). The Clinical Group with cognitive complaints scored lower than age-adjusted population norms in tests of attention, processing speed, memory, and executive function, and significantly more scored in the extremely low range than the Non-Clinical Group (38% vs. 14%, p<0.04). The Clinical Group also reported higher levels of depression, anxiety, fatigue, PTSD and functional difficulties and lower quality of life. In logistic regression analysis, scoring in the extremely low range was predicted by acute COVID-19 symptoms, current depression score, number of medical comorbidities and subjective cognitive complaints in the areas of memory, language, and executive functions. IL-6 correlated with acute COVID symptoms, number of medical comorbidities, fatigue, and measures of executive function. CRP correlated with current COVID symptoms, depression score and, inversely, with quality of life.
Conclusion
Results suggest the existence of extremely low neuropsychological test performance experienced by some individuals months after acute COVID-19 infection, affecting multiple neurocognitive domains. This extremely low neuropsychological test performance is associated with worse acute COVID-19 symptoms, depression, medical comorbidities, functional complaints, and subjective cognitive complaints. Exploratory correlations with pro-inflammatory cytokines support further research into inflammatory mechanisms and viable treatments.