This study has showed that 1) CSF levels of 5-HIAA were significantly reduced, and that of HVA tended to decrease, in cases of pathologically advanced LBD, and 2) the combination of HVA, 5-HIAA, t-tau, p-tau, and Aβ 1–42 in CSF usefully distinguishes among controls, DLB, DLB with AD and AD. Here, MAPT is linked to Alzheimer disease.