E2 ModerateModerate confidencePEM not requiredCross-SectionalPeer-reviewedReviewed
The feeling of fatigue--fatigue severity by unidimensional versus composite questionnaires.
Naschitz, Jochanan E, Rozenbaum, Michael, Shaviv, Nomi et al. · Behavioral medicine (Washington, D.C.) · 2004 · DOI
Quick Summary
This study compared two different questionnaires used to measure fatigue in ME/CFS patients and other groups with fatigue. Researchers found that a simple one-question fatigue scale and a more detailed multi-part fatigue scale gave very similar results, suggesting the simpler tool works just as well for tracking how severe someone's fatigue is.
Why It Matters
Choosing the right tool to measure fatigue is crucial for both clinical care and research. This study provides evidence that ME/CFS patients and clinicians can use a simple, quick fatigue severity scale without sacrificing accuracy, making fatigue monitoring more practical in clinical settings and reducing patient burden in research studies.
Observed Findings
- Cross-sectional correlations between CH and FI total scores were strong (r=.74, p<.0001)
- Longitudinal correlations in CFS patients were even stronger, particularly for social impact (r=.87) and total scores (r=.90)
- Physical fatigue correlations were weaker than cognitive and social domains in cross-sectional analysis (r=.603 vs .78 and .66)
- All correlations between CH and FI subscales were statistically significant (p<.0001 or better)
Inferred Conclusions
- The unidimensional Chalder Fatigue Severity Scale captures fatigue severity comparably to the more complex multidimensional Fatigue Impact Scale in CFS populations
- Simpler fatigue measurement tools may be sufficient for general fatigue assessment and longitudinal monitoring in CFS
- The strong longitudinal correlations (r=.90 for total scores) suggest consistency of both instruments over time in CFS patients
Remaining Questions
- Does the simpler CH scale adequately detect clinically meaningful changes in fatigue within individual CFS patients over longer time periods?
- How do these questionnaires compare to objective measures of fatigue or physical function (e.g., exercise testing, activity monitoring) in ME/CFS?
- Are there ME/CFS-specific domains of fatigue impact that may not be captured by either questionnaire?
What This Study Does Not Prove
This study does not establish whether either questionnaire accurately captures the underlying biological mechanisms of ME/CFS fatigue or distinguishes ME/CFS from other fatiguing conditions. Correlation between two measurements does not prove that the simpler scale detects all relevant changes in fatigue over time, nor does it address whether fatigue questionnaires correlate with objective biomarkers of disease activity.
Tags
Symptom:Fatigue
Method Flag:Weak Case DefinitionNo ControlsSmall Sample
Metadata
- DOI
- 10.3200/BMED.29.4.167-174
- PMID
- 15369197
- 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 →
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