Parkinson's disease

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. For more information, see Factsheet 442, Rarer causes of dementia.

Dementia with Lewy bodies (DLB) is a form of dementia that shares characteristics with both Alzheimer's and Parkinson's diseases. It accounts for around four per cent of all cases of dementia in older people.

For more information on the symptoms of DLB, how it is diagnosed and how it is treated see Factsheet 403, What is dementia with Lewy bodies?