1. Department of Neurology; University Hospital “12 de Octubre”; Madrid Spain
2. Department of Medicine, Faculty of Medicine; Complutense University; Madrid Spain
3. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas; Madrid Spain
4. G. H. Sergievsky Center, College of Physicians and Surgeons; Columbia University, New York; New York USA
5. Department of Neurology, College of Physicians and Surgeons; Columbia University, New York; New York USA
6. Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons; Columbia University, New York; New York USA
7. Department of Epidemiology; Mailman School of Public Health; Columbia University, New York; New York USA