Parkinson's Disease Dementia

The key brain changes linked to Parkinson’s disease and Parkinson’s disease dementia are abnormal microscopic deposits composed chiefly of alpha-synuclein, a protein found widely in the brain with a normal function not yet known. The deposits are called “Lewy bodies” after Frederick H. Lewy, M.D., the neurologist who discovered them while working in Dr. Alois Alzheimer’s laboratory during the early 1900s.

Lewy bodies are also found in several other brain disorders, including Lewy body dementia (LBD). Evidence suggests that Lewy body dementia, Parkinson’s disease and Parkinson’s disease dementia may be linked to the same underlying abnormalities in the brain processing of alpha-synuclein. Another complicating factor is that many people with both Lewy body dementia and Parkinson’s disease dementia also have plaques and tangles — hallmark brain changes linked to Alzheimer's disease.