In a retrospective, longitudinal study, University of Cincinnati scientists analyzed data from patients at high risk of developing Alzheimer’s Disease and found, elevated levels of the highly soluble, 42-amino acid-long beta-amyloid (Aβ42) in the cerebrospinal fluid (CSF) at baseline is more predictive of slower progression of clinical dementia than lower levels of brain amyloid or lower levels of phosphorylated-tau, or total tau. The study showed patients with an Aβ42 concentration of 270 picograms per milliliter in the CSF can remain cognitively normal regardless of the buildup of amyloid plaques in their brains.