E2 ModeratePreliminaryPEM ?Cross-SectionalPeer-reviewedMachine draft
Assessment of dynamic cerebral blood flow changes during cognitive tasks in patients with post-COVID-19 syndrome.
Kutz, Dieter F, Garbsch, René, Mooren, Frank C et al. · Brain communications · 2026 · DOI
Quick Summary
This study looked at how blood flow in the brain changes when people with post-COVID-19 syndrome try to do mental tasks. Researchers used special infrared cameras to watch blood flow in the thinking part of the brain while patients did concentration exercises. They found that people with post-COVID-19 had unusual, less flexible blood flow patterns compared to healthy people, which may help explain why they feel mentally tired and have trouble concentrating.
Why It Matters
This research provides objective neurobiological evidence of cognitive dysfunction in post-COVID-19 syndrome and suggests similar mechanisms may affect ME/CFS patients. The novel analytical approach could become a biomarker for disease severity and cognitive symptom burden, potentially enabling better diagnosis and monitoring of treatment effectiveness in both conditions.
Observed Findings
- Post-COVID-19 syndrome patients showed reduced temporal variability of brain blood flow during cognitive tasks compared to coronary artery disease patients
- Post-COVID-19 syndrome patients showed elevated spatial variability (more uneven blood flow patterns across brain regions) during cognitive tasks
- Spatial variability progressively increased from healthy controls → coronary artery disease patients → post-COVID-19 syndrome patients
- Increased spatial blood flow variability was correlated with longer reaction times and lower accuracy on cognitive tasks
- These patterns were observed in both Flanker and N-back cognitive tasks, with strongest associations in the N-back task
Inferred Conclusions
- Dynamic cerebral blood flow regulation is altered in post-COVID-19 syndrome, characterized by reduced flexibility in local blood flow responses but increased spatial inconsistency across brain regions
- Abnormal blood flow variability patterns may contribute to or reflect the cognitive fatigue and diminished performance observed in post-COVID-19 syndrome
- The simultaneous analysis of temporal and spatial blood flow variability provides a more complete picture of hemodynamic dysfunction than either measure alone
- This fNIRS methodology is suitable for assessing and monitoring cerebral blood flow regulation changes in post-COVID-19 syndrome and potentially in ME/CFS
What This Study Does Not Prove
This study does not prove that blood flow changes are the primary cause of cognitive fatigue—only that they are associated with it. The cross-sectional design cannot establish whether these blood flow patterns precede, follow, or are independent of post-COVID-19 syndrome onset. Results are limited to post-COVID-19 syndrome and require validation in ME/CFS populations before conclusions can be generalized.
Tags
Symptom:Cognitive DysfunctionFatigue
Biomarker:Neuroimaging
Phenotype:Long COVID Overlap
Method Flag:Weak Case DefinitionSmall SampleExploratory OnlyMixed Cohort