Striatal ß-amyloid in dementia with Lewy bodies but not Parkinson's disease.

ABSTRACT

Professor Jellinger first identified that striatal Aß deposition at postmortem seemed to differentiate cases of dementia with Lewy bodies (DLB) from those with Parkinson's disease dementia (PDD), a finding subsequently questioned. Our replication study in 34 prospectively studied cases assessed the ability of striatal Aß deposition to differentiate DLB from PDD, and also assessed the relationship between striatal and cortical Aß deposition and α-synuclein-immunoreactive pathologies, using previously published protocols. Cases with DLB had significantly shorter durations and greater dementia severities compared with cases with PDD. Striatal Aß-immunoreactive plaques were only consistently found in cases with DLB and correlated with both the severity (positive correlation) and duration (negative correlation) of dementia. Striatal Aß-immunoreactive plaques also positively correlated with the severity of α-synuclein-immunoreactive pathologies as well as cortical Aß-positive plaques. Striatal Aß deposition positively predicted dementia in Lewy body cases with high specificity and had the greatest sensitivity to differentiate DLB from PDD with 100% negative predictive value. These data suggest that striatal Aß deposition in Lewy body diseases contributes to early dementia and in these cases may impact on the efficacy of treatments targeting the striatum.