Lleó A, et al. - In this investigation involving 467 subjects from the BIOMARKAPD study with a minimum of two serial cerebrospinal fluid (CSF) samples, researchers analyzed within-person trajectories of CSF biomarkers in Alzheimer's disease (AD). They included patients with diagnoses of subjective cognitive decline (n=75), mild cognitive impairment (n=128), and AD dementia (n=110), as well as a group of cognitively unimpaired subjects (n=154). In controls, investigators found that total tau (t-tau), phosphorylated tau (p-tau), neurofilament light (NfL), and YKL-40 CSF levels were 2% higher per year of baseline age. Levels of t-tau were 1% lower and levels of p-tau did not change per baseline age year in AD. During the period of study, only NfL and YKL-40 increased longitudinally. With age, all four CSF biomarkers increase, but this effect for t-tau and p-tau is different in AD.