Gregg S. Day

Gregg S. Day, M.D., is an Associate Professor of Neurology at the Mayo Clinic in Jacksonville, Florida, where he serves as Director of the Division of Behavioral Neurology and Vice Chair of Research in the Department of Neurology. He is a consultant neurologist and clinical researcher specializing in dementia, including Alzheimer’s disease, rapidly progressive dementias, autoimmune encephalitis, and treatment-responsive cognitive disorders.

• Primary Appointment: Consultant, Department of Neurology
• Academic Rank: Associate Professor of Neurology
• Institution: Mayo Clinic, Jacksonville, FL
• School: College of Medicine and Science
• Department: Department of Neurology

Dr. Day’s research focuses on improving the clinical diagnosis, characterization, and treatment of neurodegenerative and autoimmune-mediated brain diseases. His work integrates neuroimaging and biofluid biomarkers to identify specific causes of dementia early in the disease course, with special emphasis on rapidly progressive forms such as Creutzfeldt-Jakob disease and autoimmune encephalitis. He leads and participates in multiple clinical trials, including the ExTINGUISH trial for NMDAR encephalitis, and is co-investigator in studies under the Alzheimer’s Disease Research Center and the Alzheimer’s Clinical Trials Consortium.

Dr. Day is actively involved in advancing diagnostic tools and treatment strategies to improve long-term patient outcomes. His research has been supported by the National Institute on Aging, National Institute of Neurological Disorders and Stroke, Alzheimer's Association, and the Chan-Zuckerberg Initiative. He has published over 70 peer-reviewed articles and is a key member of the Memory Disorders Laboratory with Dr. Neill R. Graff-Radford.

His scientific awards and honors include:

• Fellow of the American Neurological Association (2024)
• Fellow of the American Academy of Neurology (2021)
• Top Performing Provider Patient Experience Award (2022, 2023)
• Sven Eliasson Award for Teaching Excellence (2019)
• Future Leader Award in Dementia (2013)
• Award on the Aging Nervous System (2024)

Dr. Day mentors trainees and leads research teams focused on biomarker discovery, clinical trials, and health equity in dementia research. He is co-principal investigator on several major grants and leads initiatives such as the May Advancing Research Equity in ADRD (MAREAS) program to improve inclusion of African American and Hispanic or Latino populations in Alzheimer’s research.

The Memory Disorders Laboratory at Mayo Clinic, co-led by Dr. Day and Dr. Graff-Radford, is affiliated with the Alzheimer’s Disease Research Center and conducts clinical and translational research on:

• Genetics of degenerative brain disease
• Biomarkers in Alzheimer’s and related dementias
• Lewy body dementia in minority populations
• Normal-pressure hydrocephalus
• Rapidly progressive dementias
• Clinicopathological studies