CSF Aβ42 and tau in Parkinson's Disease with Cognitive Impairment

We tested the hypothesis that the CSF biomarker signature associated with Alzheimer's disease (AD) is present in a subset of individuals with Parkinson's disease and Dementia (PD-D) or with PD and Cognitive Impairment, Not Dementia (PD-CIND). We quantified CSF A beta(42), total tau (T-tau), and phospho-tau (P181-tau) using commercially available kits. Samples were from 345 individuals in seven groups (n): Controls <= 50 years (35), Controls > 50 years (115), amnestic Mild Cognitive Impairment (aMCI) (24), AD (49), PD (49), PD-CIND (62), and PD-D (11). We observed expected changes in AD or aMCI compared with age-matched or younger controls. CSF Ab42 was reduced in PD-CIND (P < 0.05) and PD-D (P < 0.01), whereas average CSF T-tau and P181-tau were unchanged or decreased. One-third of PD-CIND and one-half of PD-D patients had the biomarker signature of AD. Abnormal metabolism of Ab42 may be a common feature of PD-CIND and PD-D. (c) 2010 Movement Disorder Society