1. Academic Unit of Neurology TBSI, Trinity College Dublin, Dublin, Ireland
2. Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, LMU Munich, Munich, Germany
3. Neurology Department (South Division), Faculty of Medicine, Universidad de Chile, Santaigo, Chile
4. Neurology Department (North division), Hospital Clínico Universidad de Chile, Santaigo, Chile
5. Instituto de Neurología, Hospital de Clínicas Montevideo, Montevideo, Uruguay
6. National Institute of Neurology & Neurosurgery, Havana, Cuba
7. National ALS Registry, CDC/ATSDR, Atlanta, GA, USA, and
8. Department of Neurology, University of Bari, Bari, Italy