currently, gastrointestinal (gi) dysfunctions in parkinson’s disease (pd) are well?recognized problems and are known to be the initial symptoms in the pathological process that eventually results in pd. many types of pd?associated gi dysfunctions have been identified, including weight loss, nausea, hypersalivation, dysphagia, dyspepsia, abdominal pain, intestinal pseudo?obstruction, constipatio...