1. Department of Speech-Language Pathology and Audiology, University of Pretoria, Pretoria, South Africa;
2. Callier Center for Communication Disorders, University of Texas, Dallas, TX, USA;
3. Ear Sciences Centre, School of Surgery, University of Western Australia, Nedlands, Australia;
4. Ear Science Institute Australia, Subiaco, Australia;
5. Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria, South Africa