E3 PreliminaryModerate confidencePEM not requiredMethods-PaperPeer-reviewedReviewed
Standard · 3 min
Reliability and validity of the Japanese version of the Chalder Fatigue Scale among youth in Japan.
Tanaka, Masaaki, Fukuda, Sanae, Mizuno, Kei et al. · Psychological reports · 2008 · DOI
Quick Summary
This study tested whether a fatigue measurement tool called the Chalder Fatigue Scale works well in Japanese. Researchers gave the scale to healthy schoolchildren and young people with childhood chronic fatigue syndrome to see if it could reliably measure how tired they were. The tool performed reasonably well and was able to tell the difference between healthy children and those with severe fatigue.
Why It Matters
Having validated fatigue measurement tools in multiple languages is essential for comparing ME/CFS research across countries and ensuring consistent diagnosis and monitoring. This study provides evidence that the Chalder Fatigue Scale can be reliably used in Japanese populations, supporting international research collaboration and enabling better identification of childhood ME/CFS cases in Japan and other Japanese-speaking regions.
Observed Findings
Four-factor structure identified via PCA, explaining 63.2% of total variance, matching the original English version structure
Internal consistency (Cronbach α) = 0.73, indicating adequate but not high internal consistency
Healthy student group had significantly lower scale scores than the childhood chronic fatigue syndrome outpatient group
Successful discrimination between healthy and severely fatigued populations
Inferred Conclusions
The Japanese version of the Chalder Fatigue Scale has satisfactory reliability and construct validity for use in research studies among healthy Japanese schoolchildren
The scale's factor structure is cross-culturally consistent with the original English version
The instrument reliably measures fatigue severity differences between healthy youth and those with childhood chronic fatigue syndrome
Remaining Questions
Does the moderate test-retest reliability (0.55) limit clinical utility for monitoring individual patient fatigue trajectories over time?
How does the scale perform in Japanese adult populations with ME/CFS compared to the adolescent sample studied?
What This Study Does Not Prove
This study does not prove that the scale is suitable for clinical diagnosis or treatment monitoring in routine care, as the authors note it is satisfactory primarily for research among healthy students. The moderate test-retest reliability (0.55) suggests the scale may not be ideal for tracking individual patients over time. The study does not establish whether the scale captures disease-specific features of ME/CFS or how it performs in adult populations.
Tags
Symptom:Fatigue
Phenotype:Pediatric
Method Flag:Weak Case DefinitionSmall SampleExploratory Only
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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