I am curious about the associations between ibs & other gi problems and parkinson's disease. what do the pd experts out there think of research on that subject?

IBS & Parkinson's: Parkinson's affects GI motility adversely. Irritable bowel syndrome is a symptom complex that in part may reflect altered GI motility. In addition, ibs is very common (>40 million americans). There is little doubt parkinson's symptoms may mimick ibs, and of course some parkinson's patients may also have ibs. I doubt there is any other significant link between the two entities.

No association: There is no known association between ibs and parkinson's although dr michael gershon who authored the second brain believes that there is an association.

Parkinson's disease: That is a fascinating subject. The autonomic nervous system (ANS) is in charge of gastrointestinal motility. Parkinson's disease (pd) is know to affect the ans. Constipation is a very significant problem in pd. Conversely, men with constipation are at a higher risk of developing pd. There is data that suggests that ANS disorders can precede pd by many years, perhaps representing a pre-morbid state.