Title : The baseline characteristics of patients with cognitive symptoms after Covid-19 infection - the PASC24 study
Abstract:
Background: A Significant proportion of COVID-19 survivors experience persistent symptoms, which might include neurological and psychiatric disturbances. This phenomenon has been termed “Post-Acute Sequelae of COVID-19” (PASC). This study seeks to chart the cognitive effects of the COVID-19 infection among the patients referred to secondary care units in Örebro County, Sweden. The aim is to increase knowledge of the underlying biological processes; how biomarkers correlate with degree of symptoms, mapping their role as diagnostic markers over time (24 months).
Methods: Fifty-six participants with suspected PASC have been recruited and are undergoing neurocognitive, psychiatric, medical, and cognitive testing. They are being followed for 24 months with repeated measurements of their physical, psychological, and neurocognitive performance over time (three visits: baseline, 12 months, 24 months) in correlation with biomarkers (blood, cerebrospinal fluid (CSF), faeces samples) and neuroradiological changes on magnetic resonance imaging (MRI).
Results: The study population is predominantly comprised of females. Almost a half of study participants have a history of previous mental problems, most often episodes of exhaustion syndrome and depression. Depressive symptoms are also common at baseline testing.
The neurocognitive testing with two digital test batteries demonstrates that the domains most affected are "attention and tempo" and, to lesser extent, "executive function". The domains: "memory" and "verbal function" tend to be less affected in contrast to the participants' reported symptoms such as forgetfulness and speech problems. A subgroup of study participants has positive biomarkers of neuroinflammation in CSF, in form of elevated levels of neurogranin and neurofilament light (NFL) without evidence of ongoing infection.
Limitations: Only the baseline characteristics of the study participants is reported here. The strength of the study lies in the follow-up of the study participants over a long period of time in correlation with a range of different biomarkers including CSF analysis to see how the disease has affected their physical, psychological, and cognitive function, their ability to be active, return to work, and their health-related quality of life.
Conclusion: Many individuals with cognitive symptoms after COVID-19 appear to have previous mental fragility. Neurocognitive testing appears to show a specific pattern of impairments with most impact on the domain: “attention and tempo”. Positive biomarkers for neuroinflammation in CSF samples of some study participants warrant further investigation and careful follow-up.