Wisconsin Registry for Alzheimer's Prevention (WRAP) — longitudinal AD-risk cohort with cognitive assessments, A/T/N CSF biomarkers (Aβ42/40, p-tau181, t-tau, NfL, neurogranin), neuroimaging (AV45/PiB PET, MRI hippocampal/entorhinal volumes), APOE genotyping, and lifestyle/vascular risk factors across 1500+ middle-aged adults with parental AD history, 20+ years of follow-up.