The Conners Continuous Performance Test CPT3<sup>™</sup>: Is it a reliable marker to predict neurocognitive dysfunction in Myalgic encephalomyelitis/chronic fatigue syndrome?

Evidence Atlas

The Conners Continuous Performance Test CPT3™: Is it a reliable marker to predict neurocognitive dysfunction in Myalgic encephalomyelitis/chronic fatigue syndrome?

Fernández-Quirós, Judith, Lacasa-Cazcarra, Marcos, Alegre-Martín, Jose et al. · Frontiers in psychology · 2023 · DOI

Quick Summary

This study tested whether a computer-based attention test called CPT3™ can reliably detect thinking and concentration problems in ME/CFS patients. Researchers compared 158 ME/CFS patients with 67 healthy people and found that ME/CFS patients performed significantly worse on measures of attention, focus, and reaction speed. The test successfully identified differences between the two groups, suggesting it could be a useful tool for doctors to help diagnose or monitor ME/CFS.

Why It Matters

ME/CFS patients often experience cognitive dysfunction ("brain fog") that is difficult to measure objectively. This study provides evidence that CPT3™ is a standardized, computerized tool that can reliably detect attention and processing speed problems, potentially helping clinicians diagnose ME/CFS and track disease severity over time. Objective cognitive testing could improve recognition of ME/CFS and support patients seeking medical validation.

Observed Findings

ME/CFS patients showed significantly worse performance than healthy controls on all main CPT3™ measures, including attention, sustained focus, vigilance, and reaction time.
Variability and Hit Reaction Time were identified as the most discriminative indicators for distinguishing ME/CFS patients from healthy controls.
ME/CFS patients exhibited slower reaction times, greater impulsivity, and atypical T-scores similar to patterns seen in Attention Deficit Hyperactivity Disorder.
Relevant correlations were found between different CPT3™ variables within the patient group, suggesting interconnected cognitive deficits.
The test successfully differentiated the two groups across multiple cognitive domains.

Inferred Conclusions

CPT3™ is a valid and useful tool for detecting neurocognitive impairments in attention and response speed in ME/CFS patients.
Response speed measures (Variability and Hit Reaction Time) are particularly sensitive markers of ME/CFS-related cognitive dysfunction.
CPT3™ could serve as an objective marker for diagnosing ME/CFS and monitoring disease severity.
The observed cognitive profile in ME/CFS shares features with attention-deficit disorders, though ME/CFS-specific mechanisms remain unclear.

Remaining Questions

What This Study Does Not Prove

This study does not prove that CPT3™ is specific to ME/CFS—similar attention problems occur in ADHD, post-COVID syndrome, and other conditions. The cross-sectional design cannot determine whether cognitive impairment causes ME/CFS symptoms or results from them. Results may not generalize to all ME/CFS populations, as participants were recruited from a specialized center and may represent a more severe subset of patients.

Metadata

DOI: 10.3389/fpsyg.2023.1127193
PMID: 36923151
Review status: Editor reviewed
Evidence level: Single-study or moderate support from human research
Last updated: 12 April 2026

About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →