Validation of the VasCog-2-WSO VCID Criteria in a Dementia-Free and Stroke-Free Community Cohort: Cardiovascular Risk and Mortality.

COVID-19, initially seen as a respiratory illness, is now recognized as a multiorgan disease affecting the central nervous system. Persistent structural and cognitive changes in brain regions linked to olfaction and cognition have been reported (). A systematic review and meta-analysis describe a pattern of cognitive impairment ranging from 1 to 12 months after COVID-19 illness, across domains, and whether there are predictors of this impairment (). From 66 studies with a total of 134 different cognitive tests, evidence was found of a global impairment in cognition across the spectrum of COVID-19 disease severity. Both hospitalized and non-hospitalized patients may experience significant residual disabilities for a long period of time (, ). The World Health Organization (WHO) has defined a condition with long-lasting problems as “post-COVID-19 condition” (PCC) (, ). A Swedish registry study comprising around 40% of the Swedish population (4.1 million individuals) found that 2% of COVID-19 cases were diagnosed as PCC (). PCC is not restricted to the elderly () and is more prevalent in females than males (). Moreover, there is an overrepresentation among people with higher education (). Several longitudinal studies show persistent symptoms, especially regarding cognitive dysfunction, in PCC (10–12). Two years after infection, the most common persisting symptoms reported were cognitive dysfunction, sensorimotor difficulties, and fatigue (). Studies show that cognitive impairment following COVID-19 improves over time, but there is currently insufficient knowledge about whether it fully resolves and, if so, how long that process takes (). Cognitive impairments appear across cognitive domains without a clear pattern, likely due to heterogeneous studies and methods (). More research is needed on which cognitive functions are most affected, how fatigue develops over time, its role in cognitive functioning, and the obstacles it poses to everyday activities. This study addresses these gaps. The study’s aim was to investigate the long-term effects of cognitive dysfunction, fatigue, and impact on activity performance following a COVID-19 infection, as well as which cognitive functions are particularly affected. What is the status of cognitive function at the 18-month follow-up after contracting COVID-19, relative to the individual’s expected level?