The vagus nerve is so interesting. From Wikipedia: http://www.wisegeek.com/what-is-the-vagus-nerve.htm So far there isn't evidence of overt vagus nerve dysfunction in ME/CFS. There is, however, evidence of reduced parasympathetic activity - which the vagus nerve controls. Check out the below article which suggests that reducing vagal nerve functioning causes an FM like condition; ie it causes greatly enhanced pain sensitivity. (Interestingly neural therapist like Mike's doctor think the autonomic nervous system plays a far more important role than the medical community realizes) : Neuroscience. 2009 Sep 19. [Epub ahead of print] Links Subdiaphragmatic vagotomy promotes nociceptive sensitivity of deep tissue in rats. Furuta S, Shimizu T, Narita M, Matsumoto K, Kuzumaki N, Horie S, Suzuki T, Narita M.Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.