We sought to determine the association between subjective and objective cognitive functions in a well-characterized cohort of adults aged 18 to 65 who meet the World Health Organization (WHO) criteria for post-COVID-19 condition (PCC)

It is unclear whether subjective and objective measures of cognitive function in PCC are correlated. Individuals with PCC frequently report subjective cognitive issues as their primary concern during clinical visits. However, the degree to which these subjective complaints correlate with objective cognitive function remains insufficiently characterized. The extent of this correlation has mechanistic and clinical implications.

This post-hoc analysis of a randomized, double-blind, placebo-controlled clinical trial includes baseline data on subjective and objective measures of cognition in a rigorously characterized cohort living with PCC. We evaluated the association between subjective and objective cognitive function, as measured by the Perceived Deficits Questionnaire, 20-item (PDQ-20), and the Digit Symbol Substitution Test (DSST) and Trails Making Test (TMT)-A/B, respectively.

A total of 152 participants comprised the baseline sample. Due to missing data, our statistical analyses included 150 for self-reported PDQ-20, 147 for combined DSST-measured cognitive function  (composite z-score of the Pen/Paper plus Online CogState Version, NcombinedDSST), 71 for in-person DSST (Pen/Paper Version), and 70 each for TMT-A and TMT-B measured cognitive function. After adjusting for age, sex, and education, the PDQ-20 was significantly correlated with the pen-and-paper DSST (β = -0.003, p = 0.002) and TMT-B (β = 0.003, p = 0.008) scores, but not with TMT-A scores (β = -0.001, p = 0.751).

Overall, a statistically significant correlation was observed between subjective and objective cognitive functions. Clinicians providing care for individuals with PCC who report subjective cognitive complaints may consider taking a measurement-based approach to cognition at the point of care, focusing exclusively on patient-reported measures.