Long COVID patients react ~3 SD slower on a 30-second test
270 post-COVID condition patients at UK and German clinics showed severe psychomotor slowing on simple and vigilance tasks versus controls, largely independent of depression, fatigue questionnaires, or sleep.
Source
Long COVID is associated with severe cognitive slowing: a multicentre cross-sectional study
Study at a glance
- Design
- Case-control — Online SRT/NVT in PCC clinics vs No-PCC and No-COVID controls; Oxford replication of Jena
- N
- N=270 · 194 Jena + 76 Oxford PCC patients vs control groups
- Population
- Adults meeting NICE post-COVID criteria and comparison controls
- Outcome
- Simple reaction-time slowing in post-COVID condition
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Patients meeting NICE post-COVID criteria (194 in Jena, Germany; 76 replication in Oxford, UK) completed 30-second Simple Reaction Time (SRT) and Number Vigilance Test (NVT) online, compared with No-PCC (prior COVID, no PCC) and No-COVID controls. Questionnaires assessed depression, anxiety, fatigue, sleep, and PTSD.
What they found
PCC mean SRT was 0.49 s vs ~0.33–0.35 s in controls—about 3.05 age-adjusted SD slower. 53.5% of PCC patients showed severe slowing (>2 SD). SRT slowing correlated with NVT slowing (35.4% variance explained) but not with PHQ-9, HADS, fatigue, sleep, or PTSD scores. Oxford replication matched Jena (2.83 z slower).
The limits
What it doesn't show
Cross-sectional clinic samples enriched for cognitive symptoms cannot establish recovery trajectories or mechanistic causes. Motor/peripheral limitations and incomplete neuropsychological batteries were not fully ruled out. Control education differed from PCC groups, and self-administered home testing introduces device variability.
Key terms
- Post-COVID condition (PCC)
- Chronic symptoms ≥12 weeks after confirmed SARS-CoV-2 infection impairing function (NICE criteria).
- Simple Reaction Time (SRT)
- 30-second task pressing spacebar when a red circle appears; primary speed measure.
- Number Vigilance Test (NVT)
- 9-minute sustained-attention task detecting rare target digit '0'.
- Age-adjusted z-score
- Reaction time expressed as SDs from age-matched No-COVID norm.
- No-PCC group
- People with prior symptomatic COVID-19 but no post-COVID condition at testing.
- Cognitive slowing
- Increased time to process information and respond—not necessarily more variable responses.
Flashcards
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Quiz yourself
How many PCC patients were included across clinics?
Common questions
How many PCC patients were tested?
270 total (194 Jena + 76 Oxford replication).
How much slower were PCC patients?
About 3.05 age-adjusted standard deviations on SRT vs No-COVID controls.
Did depression explain the slowing?
No—questionnaire depression, anxiety, fatigue, and sleep did not account for SRT slowing.
Was the finding replicated?
Yes—Oxford PCC patients showed similar slowing to the Jena cohort.
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