Clinical correlates of pathology in the claustrum in Parkinson's disease and dementia with Lewy bodies.

Dementia and visual hallucinations are common complications of Parkinson's disease (PD), yet their patho-anatomical bases are poorly defined. We studied alpha-synuclein (alphaSyn), tau and amyloid-beta (Abeta) pathology in the claustrum of 20 PD cases without dementia, 12 PD cases with dementia (PDD) and 7 cases with dementia with Lewy bodies (DLB). alphaSyn positivity was observed in 75% of PD cases without dementia and in 100% of PDD and DLB cases. Abeta was observed in the claustrum in 25% of PD, 58% of PDD and 100% of DLB cases. Tau was negligible in all cases restricting further analysis. Compared to PD cases without dementia, PDD cases demonstrated a significantly greater alphaSyn burden in the claustrum (p=0.0003). In addition, DLB cases showed a significantly increased alphaSyn deposition when compared to PDD (p=0.02) and PD without dementia (p=0.0002). A similar hierarchy, PD