Orthostatic Intolerance

1 Schondorf and Freeman 1999 — Importance of OI in CFS

Full Citation:: Schondorf R, Freeman R@. The importance of orthostatic intolerance in the chronic fatigue syndrome. American Journal of Medical Sciences. 1999;317(2):117–123. DOI:: 10.1097/00000441-199902000-00006 PMID:: 10037115 Key Findings::

- Established orthostatic intolerance as a frequent and clinically important feature of CFS
- Demonstrates treatable autonomic dysfunction underlying many CFS symptoms
- Prevalence estimates across studies range from 50–97% depending on testing method and population
- Supports universal OI screening as a standard component of ME/CFS clinical evaluation