Event-Related Potential (ERP) Components in Clinical Diagnosis

A cross sectional cohort study design with four groups will be implemented to determine how ERPs can provide diagnostic information and alter clinical management beyond that of neuropsychological testing alone in patients with Alzheimer's disease (AD) or Mild Cognitive Impairment (MCI). Secondary Objectives: * To determine the impact of ERP testing (using cognitive health assessment reports) on change in research grade clinical diagnosis * To determine the degree of correlation between quantitative ERP measures with neuropsychological testing performance using a standardized neuropsychological battery. 75 mild AD dementia and 75 MCI due to any etiology, 25 Older Adults (OA) and 25 Younger Adults (YA) will be enrolled over the course of two years. Each subject will participate in the study for 1 visit. The in person 50-60-minute testing session consists of a neuropsychological battery, and an EEG session with computer tasks including the Auditory Oddball paradigm, a Continuous Visual Memory Test, Auditory Evoked Potentials, Visual Evoked Potentials, the Erikson Flanker Task, and the Hayling Task.