I am interested in how cognitively normal older people function on neuropsychological tests in comparison to how older persons function who are in the earliest stages of neurologic disorders, particularly dementia-spectrum conditions such as Alzheimer's Disease. Neuroscientists need to understand normal cognition -- how one person's cognitive abilities vary from another as well as how all cognitive abilities fluctuate over time for cognitively normal older persons. Much of my research has looked at how well various cognitive tests, test scores, and algorithms that use these scores can best detect pathologic neurologic conditions (e.g., Alzheimer's Disease and other dementia-spectrum illnesses) at their earliest stage. This research has been influential in re-designing two of the most frequently used cognitive tests in the world (i.e., the Wechsler Intelligence and Memory Scales). Our research is supported by Mayo Clinic's Alzheimer's Disease Research Center and Mayo's Alzheimer's Disease Patient Registry.