E2 ModerateModerate confidencePEM unclearCross-SectionalPeer-reviewedReviewed
Subcortical brain segment volumes in Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
Addiego, Florencia Martinez, Zajur, Kristina, Knack, Sarah et al. · Life sciences · 2021 · DOI
Quick Summary
Researchers used brain imaging to measure the size of deep brain structures in people with ME/CFS, Gulf War Illness, and healthy controls. They found that men and women with these conditions had different patterns of brain volume changes, suggesting that sex differences play an important role in how these illnesses affect the brain. The findings suggest that previous brain imaging studies may need to be reconsidered to account for whether participants were male or female.
Why It Matters
This study provides evidence that ME/CFS involves measurable changes in brain structure, and importantly, shows that these changes differ between men and women. Understanding sex-specific brain differences may help researchers develop better diagnostic approaches and personalized treatments for ME/CFS and similar conditions.
Observed Findings
- Female ME/CFS patients had smaller left putamen volumes compared to healthy female controls
- Female ME/CFS patients had smaller right caudate volumes compared to healthy female controls
- Female ME/CFS patients had smaller left cerebellar white matter volumes compared to healthy female controls
- Male ME/CFS patients had larger left hippocampus volumes compared to male GWI patients
- Gulf War Illness patients had significantly larger anterior and midanterior corpus callosum volumes than ME/CFS patients
Inferred Conclusions
- Sexual dimorphisms contribute significantly to pathological brain changes in both ME/CFS and GWI, with distinct patterns in men versus women
- CFS and GWI represent related but distinct neurobiological conditions, supported by their different volumetric signatures
- Gender should be incorporated as a critical variable in future ME/CFS neuroimaging studies and previous studies may require reanalysis with gender stratification
Remaining Questions
- Do these volume differences progress or change over time, or are they stable features of the illness?
- What mechanisms—inflammatory, metabolic, neuroplastic, or other—underlie these sex-specific volumetric changes?
What This Study Does Not Prove
This study documents associations between disease status and brain volume but does not establish causation or whether these volume differences cause ME/CFS symptoms or result from the illness. Cross-sectional design prevents determination of whether these changes precede symptom onset or progress over time. The findings cannot be generalized to all ME/CFS patients without larger longitudinal studies.
Tags
Symptom:Orthostatic Intolerance
Biomarker:Neuroimaging
Method Flag:Strong PhenotypingSex-StratifiedWeak Case DefinitionExploratory Only
Metadata
- DOI
- 10.1016/j.lfs.2021.119749
- PMID
- 34214570
- 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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