Carole Cassidy, I was most interested in what Dr. Langston had to say about inflamation from injury or disease as a possible causative factor when he spoke to participants in the PAN Forum. My husband sustained a real hit in the head as a young naval aviator and later suffered a terrible rupture of several discs in his back for which he had a laminectomy too many years later and after much suffering. After picking up that filing cabinet, inflamation was a close companion. Either incident or the problem of chronic inflamation could have been a factor. Barb Brock