1. Biomedical Engineering Group, E.T.S. Ingenieros de Telecomunicación, University of Valladolid, Campus Miguel Delibes, Paseo de Belén 15, 47011, Valladolid, Spain
2. Biomedical Engineering Group, E.T.S. Ingenieros de Telecomunicación, University of Valladolid, Valladolid, Spain
3. Department of Neurology, Hospital Universitario Río Hortega, Valladolid, Spain
4. Department of Clinical Neurophysiology, Hospital Universitario Río Hortega, Valladolid, Spain