Originally Posted by johnt

The link states:

"Researchers from the Central Hospital of Rogaland in Stavanger, Norway, found that nearly 80% of the Parkinson’s patients they studied over an eight-year period developed dementia. ... In the study, 224 Parkinson’s patients were interviewed. ... Patients were evaluated for dementia at their initial examination and four and eight years later. At the beginning of the study, 51 patients with PD had dementia. A total of 43 and 28 new cases of dementia were identified after four and eight years of follow-up, respectively."

Where does the 80% come from?

I make it (51 + 43 + 28)/224 = 54.5%

Still not good news, but better.

John