John Daniel O'Sullivan, MD, is a practicing neurologist with a specific interest in movement disorders research. He has led and coordinated multiple clinical trials in Parkinson's disease and has over 75 peer-reviewed publications in leading journals. Dr. O'Sullivan has served on a number of committees of the International Movement Disorders Society and is currently President of the Movement Disorders Society of Australia & New Zealand (MDSANZ). He was previously Chairman of the MDSANZ Clinical Research and Trials group, coordinating movement disorders clinical trials throughout Australia & New Zealand. His clinical research and investigator-initiated trials have led to the recognition of the syndrome of dopamine dysregulation in Parkinson's disease, which can complicate dopamine replacement therapy in some patients. Dr. O'Sullivan currently oversees multiple research projects on non-motor symptoms in Parkinson's disease.