Hi Brian, I think this internal shaking to which you refer is called "akathisia" or perhaps it is spelled "akathesia" -- some have described a type of "psychomotor restlessness" (see "Panic Attacks in Parkinson's Disease : A long term complication of levodopatherapy" by A Vasquez, et al, Acta Neurol Scand 1993: 87: 14 - 18) It is not something which is written about much. However, I did find in the PAWA Newsletter of January 1994 (Vol 11:No 1) my write up of this phenomena which goes "A Miami, USA study reported on a new, previously undescribed sensory symptom of PD. 44% of the surveyed patients with PD suffered from a sensation of "internal tremor" inside the chest, abdomen, arms or legs. (This was a report from the WORLD CONGRESS OF NEUROLOGY, Sept 1993, Vancouver) You may recall the cute little graphic underneath this which shows two frogs, each sitting on a mushroom, and one says to the other "no matter what I do, I still feel jumpy all the time." Anyway, I don't have PD but I sure had that feeling all during the Perth Conference! Regards Joy Graham