Abstract
Measurement of τ-protein and β-amyloid1–42 (Aβ42) in cerebrospinal fluid (CSF) has gained increasing acceptance in the differential diagnosis of Alzheimer’s disease. We investigated CSF τ-protein and Aβ42 concentrations in 73 patients with advanced idiopathic Parkinson’s disease with dementia (PDD) and 23 patients with idiopathic Parkinson’s disease without dementia (PD) and in a comparison group of 41 non-demented neurological patients (CG) using commercially available enzyme-linked-immunoabsorbant-assay (ELISA). τ-Protein levels were statistically significantly higher and Aβ42 lower in the PDD patients compared to PD patients and the CG. This observation was most marked (p < 0.05) in a subgroup of patients with PDD carrying the apolipoprotein genotype Ε3/Ε3. The distribution of the apolipoprotein genotypes in PDD and PD patients was similar to that of the CG. Although a significant difference in τ-protein values was observed between PDD and CG, no diagnostic cut-off value was established. These findings suggest that such protein CSF changes may help to support the clinical diagnosis of cognitive decline in PD and that there may be apolipoprotein-E-isoform-specific differences in CSF protein regulation in advanced PDD.