MAPT and Parkinson disease: We hypothesized that (i) patients in the high dementia risk PD group would have the highest levels of brain inflammation and/or tau accumulation at this early point in the disease course; (ii) the degree of neuroinflammation would correlate with tau burden in the brain; and (iii) regional neuroinflammation and/or tau accumulation would be associated with early deficits in cognitive function.