Department of Neurology, Harvard Medical School, Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health at Hebrew SeniorLife, Boston, MA, USA. Institut Guttmann de Neurorehabilitació, Guttmann Brain Health Institute, Barcelona, Spain. Department de Medicina, Facultat de Medicina i Ciències de la Salut - Campus Clínic, Universitat de Barcelona, Barcelona, Spain.