Cognitive Impairment and Risk Factors in Post-COVID-19 Hospitalized Patients

Numerous reports regarding cognitive deficits after the coronavirus disease 2019 (COVID-19), described as "brain fog," have been published. However, the clinical presentations and risk factors of post-COVID-19 cognitive impairment are controversial. This study aimed to assess (a) the prevalence of cognitive impairment after COVID-19 hospitalization, (b) characteristics of the cognitive deficits, (c) risk factors of post-COVID-19 cognitive impairment, and (d) comparison of cognitive function between post-COVID-19 patients and healthy people.

The study comprised 34 SARS-CoV-2-infected patients, admitted to the Neurological Institute of Thailand during the peak of COVID-19 pandemic in 2021-2022. These patients came for neuropsychological and clinical evaluations at 2-week follow-up visit. The cognitive impairment and characteristics were measured by TMSE and MoCA. Clinical risk factors and post-COVID-19 cognitive impairment were assessed. The comparison of cognitive function in post-acute COVID-19 patients and 22 healthy controls was also performed.

The prevalence of post-COVID-19 cognitive impairment defined by a total MoCA score below 25 points was 61.76%. Years of education were the only predictive factors related to cognitive impairment. Our multivariate analysis revealed no statistical difference in cognitive outcomes between post-acute COVID-19 patients and healthy controls.

This study showed a moderate prevalence of cognitive dysfunction after COVID-19 hospitalization similar to previous reports. However, there was no significant difference in cognitive measurements between these patients and healthy people. Whether SARS-CoV-2 infection causes cognitive dysfunction is a myth or fact that still has a long way to prove via further longitudinal study.