1. From the Department of Neurology (M.A., M.C.-J., C.S., A.D., A.V., K.B., M.G.B.) and the Headache Emergency Centre (A.D.), Assistance Publique, Hôpitaux de Paris, University Hospital Lariboisière, Paris, France; and the Department of Neurology (M.A.), University Hospital, Berne, Switzerland.