Alzheimer’s disease (AD) is an irreversible neurodegenerative disease that results in a loss of mental function caused by the deterioration of brain tissue. It is the most common cause of dementia among people over the age of 65, affecting an estimated 5.5 million Americans, yet no prevention methods or cures have been discovered. For more information about Alzheimer’s disease, visit the Alzheimer’s Association. The goal of the ADNI study is to track the progression of the disease using biomarkers, together with clinical measures, to assess the brain’s structure and function over the course of four disease states. Details about ADNI cohorts can be found in the About section.