Moreover, differentiation is feasible between, firstly, Parkinson's disease and the Parkinson plus" syndromes multiple system atrophy and progressive supranuclear palsy, secondly, multiple system atrophy/progressive supranuclear palsy and the other Parkinson plus" syndromes dementia with Lewy bodies and corticobasal degeneration, and, thirdly, Alzheimer's disease and other forms of dementia.