1. Department of Communication Pathology, University of Pretoria, Pretoria, South Africa.
2. Ear Sciences Centre, School of Surgery, The University of Western Australia, Nedlands, Australia.
3. Ear Science Institute Australia, Subiaco, Australia.
4. Institute of Child Health, University of Ibadan, Ibadan, Nigeria.
5. Ear, Nose, and Throat Department, University College Hospital, Ibadan, Nigeria.