Blood Biomarkers

This is a three-cohort, randomized, double-blinded , sham-controlled, single-center, early feasibility research trial to determine whether organ-specific biologic effects on platelet activity and coagulation are achievable through selective ultrasound of the spleen utilizing low-energy (diagnostic-level) insonification. * Group 1: Focused insonification at center of the spleen. * Group 2: Prolonged duration insonification at center of the spleen * Group 3: Prolonged duration insonification across the spleen. Participants will receive 30 minutes of sham stimulation in the randomized group that is assigned to them, followed by active stimulation within the same group. Blood biomarkers (local and systemic) will be measured before and at several timepoints after stimulation to measure the molecular and cellular effects of the device

The goal of this observational study is to estimate the screen performance of blood biomarkers of interest (Aβ40 and Aβ42, P-Tau181, P-Tau217, GFAP and NfL) in patients with Alzheimer's disease (AD), mild cognitive impairment due to AD, and cognitively normal individuals. The main questions it aims to answer are: * to identify core blood biomarker suitable for early screening of AD. * to establish a comprehensive model for the early identification of AD.