Scientists have modified a test for early diagnosis of prion diseases with the goal of improving early diagnosis of Parkinson's disease and dementia with Lewy bodies. The group tested cerebral spinal fluid samples from people with Parkinson's disease; people with dementia with Lewy bodies; and controls, some of whom had Alzheimer's disease. The test correctly excluded all the controls and diagnosed both Parkinson's disease and dementia with Lewy bodies with 93 percent accuracy.