Long COVID is associated with severe cognitive slowing

Here’s a summary of the study “Long COVID is associated with severe cognitive slowing”:

Background and Methods: The study investigated cognitive slowing in post-COVID-19 conditions (PCC). Researchers hypothesized that a common deficit in PCC patients might be generalized cognitive slowing. To test this, 270 patients diagnosed with PCC at two clinics in the UK and Germany performed two web-based cognitive tasks: Simple Reaction Time (SRT) and Number Vigilance Test (NVT). Their performance was compared with two control groups: those who had COVID-19 but did not develop PCC (No-PCC group) and uninfected individuals (No-COVID group)​​.

Key Findings:

  • Pronounced Cognitive Slowing: PCC patients exhibited significant cognitive slowing compared to age-matched healthy controls. In the SRT task, PCC patients’ reaction times were approximately three standard deviations slower than controls. This was consistent across clinic samples in Germany and the UK​​.
  • Persistence in More Demanding Tasks: The cognitive slowing observed in PCC patients extended to the more cognitively demanding NVT task. The reaction time on the NVT strongly correlated with their performance on the SRT, suggesting a consistent pattern of cognitive slowing across different types of cognitive tasks​​.
  • Depression and Cognitive Slowing: Analysis revealed that depression levels and reaction times in both SRT and NVT were significant predictors of PCC. These metrics effectively distinguished PCC patients from those who had COVID-19 but did not develop PCC​​.
  • Lack of Correlation with Pre-existing Conditions: PCC patients who were hospitalized due to COVID-19 showed lower accuracy in the NVT, but there was no difference in reaction time. Pre-existing psychological or neurological conditions did not differentiate PCC patients in terms of cognitive performance​​.
  • Cognitive Impairment and Time: Interestingly, a longer duration of PCC was linked with more severe cognitive slowing, suggesting that cognitive impairments in PCC do not improve over time and may even worsen​​.

Conclusion and Implications: The study robustly demonstrates that severe cognitive slowing is a distinctive feature of PCC, differentiating these patients from those who had COVID-19 but did not develop PCC. This finding is critical for understanding the cognitive impairments associated with PCC and highlights the need for targeted diagnostic and therapeutic approaches.

Read More: https://www.medrxiv.org/content/10.1101/2023.12.03.23299331v1.full.pdf

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