Roy Ervin Twyman, MD, has nearly 20 years' experience in neuroscience pharmaceutical drug development, most recently as senior vice president at Janssen Pharmaceutical Research & Development LLC, where he was the Alzheimer's disease area leader in the Neuroscience Therapeutic Area. Dr. Twyman has served on advisory committees and panels of the U.S. Food and Drug Administration and the Institute of Medicine. Board-certified in psychiatry and neurology, Dr. Twyman was an academic neurologist and has written chapters in several books and published numerous articles in peer-reviewed medical and scientific journals.