Attention
Long COVID patients react ~3 SD slower on a 30-second test
Metadata + PaperFren explanation · cc by · source: Europe PMC
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.
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.
Key findings
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).
Methodology
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.
Limitations
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.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
In post-COVID clinics, simple reaction time can be severely slowed versus controls.
In NICE-defined post-COVID clinic samples, simple reaction time can be severely slowed (~3 SD vs controls), with more than half of patients past a >2 SD threshold, and the slowing replicates across UK and German sites. That supports a position that some people with PCC have large, objective psychomotor slowing—not only self-reported fog.
Evidence for the claim as stated.
Cognitive complaints can remain part of lasting post-COVID syndrome into the second year.
Among adults still meeting post-COVID syndrome criteria into the second year after infection, cognitive complaints remain part of a durable symptom pattern dominated by fatigue and exercise intolerance; most previously recovered controls stay well.
Scope note — different outcome — objective SRT, not year-two symptom persistence
Limits the claim's scope: a different population, assay, or outcome.
Fatigue strongly predicts work and social disability in a large post-COVID clinic app cohort.
In a large UK post-COVID clinic app cohort, fatigue was the strongest predictor of moderately severe work and social disability (WSAS ≥20), outranking depression and a cognition PROM.
Scope note — different outcome — psychomotor slowing vs WSAS disability
Limits the claim's scope: a different population, assay, or outcome.
Objective slowing and self-reported fatigue or mood do not always move together.
Objective psychomotor slowing in PCC clinic samples does not track questionnaire fatigue or mood scores in the multicentre SRT study—so a claim that “cognitive slowing is just measured fatigue/depression” is not supported there.
Evidence for the claim as stated.
Fatigue-led WSAS disability models and multicentre SRT slowing measure different outcomes in differently selected post-COVID groups. UK clinic app data put fatigue first among PROM predictors of work/social disability; SRT work shows large objective slowing that does not correlate with fatigue scores. Both can be true without either estimate falsifying the other—the limit is which claim (disability drivers vs psychomotor speed) you are defending.
Evidence for the claim as stated.
NICE clinic PCC, nested questionnaire PCS with outpatient workups, and U09.9 EHR codes are different case definitions with different selection biases. Large objective slowing in specialty clinics need not describe every coded or community PCS case—this is a scope limit, not evidence that one study’s slowing estimate is wrong.
Evidence for the claim as stated.
Year-two outpatient assessments found persistent symptoms without lab support for viral persistence, EBV reactivation, adrenal failure, or increased complement turnover. Durable cognitive complaints therefore do not, in that cohort, pin a single blood-testable mechanism—an open mechanistic limit rather than a conflict with the SRT slowing finding.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Fatigue-led WSAS disability models and multicentre SRT slowing measure different outcomes in differently selected post-COVID groups. UK clinic app data put fatigue first among PROM predictors of work/social disability; SRT work shows large objective slowing that does not correlate with fatigue scores. Both can be true without either estimate falsifying the other—the limit is which claim (disability drivers vs psychomotor speed) you are defending.
NICE clinic PCC, nested questionnaire PCS with outpatient workups, and U09.9 EHR codes are different case definitions with different selection biases. Large objective slowing in specialty clinics need not describe every coded or community PCS case—this is a scope limit, not evidence that one study’s slowing estimate is wrong.
- Supports · Most PCS patients still ill in year two
- Supports · U09.9 coding reveals long COVID clusters and gaps
Year-two outpatient assessments found persistent symptoms without lab support for viral persistence, EBV reactivation, adrenal failure, or increased complement turnover. Durable cognitive complaints therefore do not, in that cohort, pin a single blood-testable mechanism—an open mechanistic limit rather than a conflict with the SRT slowing finding.
- Supports · Most PCS patients still ill in year two
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