1. De La Salle University, Health Sciences Campus; Clinical Epidemiology Unit; Cong. Road Dasmariñas Cavite 4114 Philippines
2. World Health Organisation (WHO); Prevention of Deafness and Hearing Impairment (PDH); CH-1211 Geneva 27 Switzerland
3. Liverpool School of Tropical Medicine; Walton Centre for Neuroscience; Pembroke Place Liverpool UK L3 5QA