Long COVID is associated with severe cognitive slowing - a multicentre cross-sectional study, 2023, Stallmach et al

Preprint
Now published, see post 5

Long COVID is associated with severe cognitive slowing

Background
COVID-19 survivors may suffer from a wide range of chronic cognitive symptoms for months or years as part of post-COVID-19 conditions (PCC). To date, there is no definitive objective cognitive marker for PCC. We hypothesised that a key common deficit in people with PCC might be generalised cognitive slowing.

Methods
To examine cognitive slowing, PCC patients completed two short web-based cognitive tasks, Simple Reaction Time (SRT) and Number Vigilance Test (NVT). 270 patients diagnosed with PCC at two different clinics in UK and Germany were compared to two control groups: individuals who contracted COVID-19 before but did not experience PCC after recovery (No-PCC group) and uninfected individuals (No-COVID group).

Findings
We identified pronounced cognitive slowing in PCC patients, which distinguished them from age-matched healthy individuals who previously had symptomatic COVID-19 but did not manifest PCC. Cognitive slowing was evident even on a 30-second task measuring simple reaction time (SRT), with PCC patients responding to stimuli ~3 standard deviations slower than healthy controls. This finding was replicated across two clinic samples in Germany and the UK. Comorbidities such as fatigue, depression, anxiety, sleep disturbance, and post-traumatic stress disorder did not account for the extent of cognitive slowing in PCC patients. Furthermore, cognitive slowing on the SRT was highly correlated with the poor performance of PCC patients on the NVT measure of sustained attention.

Interpretation
Together, these results robustly demonstrate pronounced cognitive slowing in people with PCC, which distinguishes them from age-matched healthy individuals who previously had symptomatic COVID-19 but did not manifest PCC. This might be an important factor contributing to some of the cognitive impairments reported in PCC patients.

https://www.medrxiv.org/content/10.1101/2023.12.03.23299331v1

 

Would be good to try these tests in people with mild and moderate ME.

 

I would even say it's better to try these tests on people with severe and very severe ME as well. Usually this patient group is excluded from any research, however “two short web-based cognitive tasks, Simple Reaction Time (SRT) and Number Vigilance Test (NVT)” would be something that could include these patient groups as well.

 

This could be pretty important. Instinctively it seems that could be relevant to disability benefits. I think the cognitive effects of me/cfs are largely skimmed over (who doesn't have brain fog?) when often patients describe them as severe.

Just skimmed through a 2013 paper that tested simple reaction time where Natelson is an author. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159443/

Problem with this paper is it's Fukuda criteria with 22 patients described as having major depression vs none in controls. All severe enough to require medication. Despite a criteria being having no major neuropsych disorder. So that's, uh, strange.

A different study https://digital.library.adelaide.edu.au/dspace/handle/2440/104051

Seems like Simple Reaction Time has been tested in cfs quite a bit, but maybe needs one big clarifying study.

 

Now published as Long COVID is associated with severe cognitive slowing: a multicentre cross-sectional study in the Lancet eClinicalMedicine.

 

Pot, kettle