[1] London Sch Hyg & Trop Med, Int Ctr Evidence Disabil, London, England
[2] Coll Med, Dept Surg, Blantyre, Malawi
[3] Queen Elizabeth Cent Hosp, Audiol Dept, Blantyre, Malawi
[4] Shandong Univ, Sch Publ Hlth, Jinan, Peoples R China
[5] Univ Pretoria, Dept Speech Language Pathol & Audiol, Pretoria, South Africa