1 From the Boston University Alzheimer's Disease Research Center and Boston University CTE Center (M.L.A.); Department of Neurology (M.L.A.), Boston University Chobanian & Avedisian School of Medicine; Department of Neurology (M.L.A.), Boston Medical Center, MA; Tanz Centre for Research in Neurodegenerative Diseases (M.C.T.), University of Toronto; Canadian Concussion Centre (M.C.T.), Krembil Brain Institute; and Memory Clinic (M.C.T.), Toronto Western Hospital, ON, Canada.