Prominent psychiatric symptoms in patients with Parkinson's disease and concomitant argyrophilic grain disease.

In Parkinson's disease (PD), cognitive decline and psychiatric symptoms may occur and very often co-exist, eventually leading to PD-dementia. We report three patients with PD who presented striking psychiatric manifestations along with mild cognitive decline not progressing to dementia across the course of disease and in which postmortem neuropathological study revealed, besides alpha-synuclein inmunoreactive Lewy-body pathology, concomitant four-repeat tau positive argyrophilic grain pathology. We consider that argyrophilic grains might have modulated the clinical presentation of PD in these patients, being the main substrate of their prominent psychiatric symptoms in the absence of definite dementia.