1. The University of Rochester Medical Center, Department of Neurology; 601 Elmwood Avenue, Box 673 Rochester New York 14642 USA
2. Psychometric Consultant; Chicago Illinois USA
3. The University of Utah; Salt Lake City Utah USA
4. The University of Rochester Medical Center, Department of Biostatistics and Computational Biology; Rochester New York USA
5. The University of Pittsburgh School of Medicine; Pittsburgh Pennsylvania USA
6. Northwestern University Feinberg School of Medicine; Chicago Illinois USA
7. Greater Los Angeles VA HealthCare System; Los Angeles California USA
8. David Geffen School of Medicine, UCLA Medical Center; Los Angeles California USA