Parkinson’s disease patients often have a dull expression, drooling, drool is saliva, the reason is that after the secretion of saliva, Parkinson’s patients can not be like normal people can be coordinated through the oral cavity, the tongue and the pharyngeal muscles, will be swallowed in a timely manner. Drooling does not indicate that Parkinson’s patients have symptoms of dementia. The incidence of Parkinson’s patients with dementia is 20%, so most Parkinson’s patients have normal intelligence and only show uncoordinated muscle activity, which leads to the symptom of drooling.