David Knopman1, Mary Sano2, Howard H Feldman3. 1. Department of Neurology, Mayo Clinic, Rochester, MN, USA. knopman@mayo.edu. 2. Department of Neurology, Icahn School of Medicine at Mt Sinai, New York, NY, USA. 3. Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.