1. Unidad de Atención Temprana y Rehabilitación Infantil, del Servicio de Medicina Física y Rehabilitación, del Hospital Materno Infantil Teresa Herrera, del Área Sanitaria de A Coruña y Cee, 15006 A Coruña, Spain
2. Facultad de Fisioterapia, Universidade da Coruña, 15471 Ferrol, Spain
3. Faculty of Medicine, University of Murcia, 30100 Murcia, Spain
4. Department of Traumatology, V. de la Arrixaca University Hospital, 30120 Murcia, Spain
5. Department of Nursing and Physiotherapy, Faculty of Nursing and Physiotherapy, Instituto de Investigación Biomédica de Salamanca (IBSAL), Campus Miguel de Unamuno s/n, 37007 Salamanca, Spain
6. Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, University College London Queen Square, London WC1N 3BG, UK