[1] Univ Western Australia, Sch Paediat & Child Hlth, Crawley, WA 6009, Australia
[2] Edith Cowan Univ, Sch Psychol & Speech Pathol, Joondalup, WA, Australia
[3] King Edward Mem Hosp, Dept Neonatal Paediat, Subiaco, WA, Australia
[4] Princess Margaret Hosp, Dept Paediat Otorhinolaryngol & Head & Neck Surg, Subiaco, WA, Australia
[5] Univ Western Australia, Sch Surg, Crawley, WA 6009, Australia
[6] State Child Dev Ctr, Perth, WA, Australia