Post-acute COVID-19 cognitive impairment and decline

Uniquely associate with
kynurenine pathway activation:
a longitudinal observation study

Preprint from medRxiv; DOI: 10.1101/2022.06.07.22276020

The authors are all Australian medical experts and researchers based in NSW at institutions including St Vincent’s Hospital, the Kirby Institute, Faculty of Medicine and School of Psychology at UNSW, School of Psychology and Medical School Macquarie University.
The findings in a nutshell
  • Clinically relevant mild-moderate cognitive impairment impacts up to 25% of patients at post acute COVID stages, and the prevalence of the cognitive impairment increased slightly over time.
  • Individuals showing evidence of mild cognitive impairment initially showed greater cognitive decline post-acute COVID than cognitively normal patients.
  • Kynurenine pathway (KP) activation was confirmed as a potential biomarker for COVID-related cognitive decline and a therapeutic target.
Overview of the paper

This study used a rigorous longitudinal design, and a set of well validated neuropsychological tools to explore cognitive change over time post-COVID infection. Participants were divided into three acute severity groups (mild, moderate and severe). Based on past research, a range of potential biomarkers and metabolic products were selected, and in addition, the components of the plasma KP activation which has been shown to be dysregulated by COVID-19 infection (including mild cases). A range of other validated clinical tools also assessed mental health (anxiety and depressive symptoms), olfaction performance, and lung function.


Mild cognitive decline (and NOT anxiety, depression, olfaction, lung function or COVID severity) was uniquely associated with KP activation suggesting a potential causal link and identifying it as a potential biomarker for COVID-related cognitive decline.

Implications for Australian workplaces

This study provides the foundation for further therapeutic intervention research that has the potential to identify and treat workers at risk of or experiencing COVID-related cognitive decline, minimising the negative implications for workplaces.

To find out more about Post-acute COVID-19 cognitive impairment and decline read the full article here.

Date published: 7 June 2022

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