1. Department of Neurology; Hospital Universitario Fundación Alcorcón; Alcorcón Madrid Spain
2. Department of Neurology; Hospital Universitario Quironsalud Madrid; Pozuelo de Alarcón Madrid Spain
3. Headache Unit, Department of Neurology; Hospital Clínico San Carlos; Madrid Spain
4. Department of Medicine, School of Medicine; Universidad Complutense de Madrid; Madrid Spain
5. Pain Clinic, Department of Anesthesiology; Hospital Universitario Fundación Alcorcón; Alcorcón Madrid Spain
6. Department of Ophthalmology; Hospital Universitario Fundación Alcorcón; Alcorcón Madrid Spain