1. Section of Neurology, Department of Medicine, Center for Memory Disturbances, University of Perugia, Sant’ Andrea delle Fratte, 06132 Perugia, Italy
2. Clinical Neurochemistry Laboratory, Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden
3. Health Planning Service, Regional Health Authority of Umbria, Department of Epidemiology, Perugia, Italy