1. Cerner LifeSciences, Beverly Hills, Irvine, California 90212, USA.
2. Allergan, Inc., Irvine, CA, USA.
3. Norwegian National Headache Centre, St Olavs Hospital, Trondheim, Norway.
4. Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
5. Albert Einstein College of Medicine, Bronx, NY, USA.