Parkinson's Dementia, The Alzheimer's Library

People with Parkinson's disease have a higher-than-average risk of developing dementia, although the majority remain unaffected. Symptoms of dementia associated with Parkinson's disease vary from person to person. The most common are memory loss, and loss of the ability to reason and to carry out everyday tasks. The person may become obsessive, and there may be a loss of emotional control, with sudden outbursts of anger or distress. Visual hallucinations may occur. Symptoms often fluctuate so that the person seems better or worse at different times. It is not yet understood how dementia occurs in Parkinson's disease. It may be that the microscopic deposits known as Lewy bodies, which occur in nerve cells in the brain stem in people with Parkinson's, have a role to play, as they do in dementia with Lewy bodies (see above). The side-effects of certain drugs for Parkinson's may exacerbate symptoms of dementia, so adjusting medication for Parkinson's is sometimes helpful.