Paradigm shift to disequilibrium in the genesis of orthostatic intolerance in patients with myalgic encephalomyelitis and chronic fatigue syndrome. — CFSMEATLAS
Paradigm shift to disequilibrium in the genesis of orthostatic intolerance in patients with myalgic encephalomyelitis and chronic fatigue syndrome.
Miwa, Kunihisa, Inoue, Yukichi · International Journal of Cardiology. Hypertension · 2020 · DOI
Quick Summary
This study looked at why people with ME/CFS struggle to stand up without feeling dizzy or unsteady. Researchers tested 72 patients and found that balance problems while standing (disequilibrium) were much more common in those who couldn't complete a 10-minute standing test than previously thought. The study suggests that poor balance, rather than just heart rate problems, may be a main reason why standing is so difficult for many ME/CFS patients.
Why It Matters
This research challenges the prevailing assumption that orthostatic intolerance in ME/CFS is primarily a cardiovascular problem. By identifying balance dysfunction as a key contributor, it opens new diagnostic and treatment pathways that may help clinicians better manage this debilitating symptom and improve quality of life for patients.
Observed Findings
Disequilibrium was present in 32% (23/72) of ME patients, compared to postural orthostatic tachycardia in 22% (16/72).
89% of patients who failed the 10-minute standing test showed disequilibrium, versus only 11% of test-completers (p<0.01).
Postural orthostatic tachycardia rates were similar between test-completers and non-completers (23% vs. 21%, p=1.00).
Among 8 patients with prior standing test records, 6 had developed disequilibrium 6-24 months after previously completing the test without balance problems.
Inferred Conclusions
Disequilibrium is a more common and important factor in orthostatic intolerance than previously recognized.
Balance dysfunction, not tachycardia alone, better predicts inability to maintain upright posture in ME patients.
Disequilibrium may develop or worsen over time in some ME/CFS patients, suggesting disease progression or neurological involvement.
Remaining Questions
What neurological or physiological mechanisms cause disequilibrium in ME/CFS patients?
Can disequilibrium be reliably measured with standardized tests, and how does it change over time in longitudinal studies?
Are there specific treatments or interventions that effectively address balance dysfunction in this population?
What This Study Does Not Prove
This study does not prove that disequilibrium is the sole cause of orthostatic intolerance—it is likely multifactorial. The cross-sectional design cannot establish causation or temporal relationships for most patients, and the small sample size limits generalizability. The study also does not identify what mechanisms underlie the disequilibrium itself.
Tags
Symptom:Orthostatic IntoleranceFatigue
Method Flag:Weak Case DefinitionNo ControlsSmall Sample