Parkinson's disease is generally recognized by the neurodegenerative symptoms of tremor, gait changes, muscular rigidity and slow movements. However, parkinson's is also associated with daytime sleepiness, fatigue, psychosis/hallucinations and dementia. The occurence of dementia in patients with parkinson's disease is quite high, acutally. The are some medications that may prove useful in slowing the progression of the dementia, such as cholinesterase inhibitors.