E2 ModeratePreliminaryPEM unclearCase-ControlPeer-reviewedMachine draft
Right arcuate fasciculus abnormality in chronic fatigue syndrome.
Zeineh, Michael M, Kang, James, Atlas, Scott W et al. · Radiology · 2015 · DOI
Quick Summary
This study used advanced brain imaging to compare 15 ME/CFS patients with 14 healthy controls. Researchers found that ME/CFS patients had less white matter (the brain's communication pathways) overall, and specific changes in fiber structure on the right side of the brain. The severity of these brain changes correlated with how sick patients felt, suggesting this could be a measurable biological marker of the illness.
Why It Matters
This study provides objective neuroimaging evidence of structural brain differences in ME/CFS, moving beyond subjective symptom reporting toward biological measures. The correlation between brain changes and disease severity offers potential for a biomarker that could improve diagnosis and monitoring of treatment response in ME/CFS patients.
Observed Findings
- Increased fractional anisotropy in right arcuate fasciculus in CFS patients (P=.0015), with FA increasing with disease severity (r=0.649, P=.026)
- Bilateral white matter volume reduction in CFS (467,581 mm³ ± 47,610) versus controls (504,864 mm³ ± 68,126), P=.0026
- Increased cortical thickness at right arcuate endpoints (middle temporal and precentral gyri) and right inferior longitudinal fasciculus endpoint (occipital lobe)
- No significant differences in cerebral blood flow measured by arterial spin labeling between groups
Inferred Conclusions
- Bilateral white matter atrophy is present in ME/CFS patients
- Right hemispheric white matter microstructural changes may reflect either degeneration of crossing fibers or strengthening of short-range fibers
- Right anterior arcuate fasciculus FA may serve as a neurobiological biomarker for CFS severity
Remaining Questions
- Does the increased FA represent pathological change or an adaptive response to illness, and what is the underlying mechanism?
- Can these brain findings predict clinical outcomes or response to treatment in CFS patients?
- Are these structural changes specific to ME/CFS or do they occur in other chronic fatiguing illnesses?
What This Study Does Not Prove
This study does not establish causation—the brain changes could be consequences of chronic illness rather than causes of ME/CFS symptoms. The small sample size and retrospective patient recruitment (waiver of consent) limit generalizability, and findings require replication in larger, prospectively enrolled cohorts before clinical application.
Tags
Symptom:Fatigue
Biomarker:Neuroimaging
Method Flag:Weak Case DefinitionSmall SampleExploratory Only
Metadata
- DOI
- 10.1148/radiol.14141079
- PMID
- 25353054
- Review status
- Machine draft
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 8 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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