Kenneth Rockwood MD MPA FRCPC is Professor, Division of Geriatric Medicine, Department of Medicine and Kathryn Allen Weldon Professor of Alzheimer Research, Dalhousie University, Halifax NS, Canada. Serge Gauthier MD FRCPC is Professor and Director of the Alzheimer’s Disease Research Unit, The McGill Centre for Studies in Aging (Le Centre McGill D’Études sur le Vieillissement), Douglas Hospital, Montréal PQ, Canada.