Immunoreactivities of amyloid β peptide(1-42) and total τ protein in lumbar cerebrospinal fluid of patients with normal pressure hydrocephalus

Immunoreactivities of amyloid beta peptide((1-42)) (Abeta42-IR) and total tau protein (TTIR) were measured in lumbar cerebrospinal fluid of 48 patients (12 patients in each group) with normal pressure hydrocephalus (NPH), vascular dementia (VD), Alzheimer's disease (AD), Parkinson's disease without dementia (PD) and 24 controls (CON) using sensitive and specific enzyme immunoassays. TTIR in NPH was not significantly changed compared with VD, PD and CON, while NPH-Abeta42-IR was significantly decreased compared with PD and CON. In AD, significant increases of TTIR and significant decreases of Abeta42-IR were found. Using a TTIR by Abeta42 plot, all NPH, PD, and CON samples were within the non-AD plot region. 92% of AD and VD samples were within the AD and non-AD area, respectively. We conclude that combined measurement of Abeta42-IR and TTIR contributes to the differential diagnosis of NPH vs. AD and of AD vs. VD, respectively.