Witzel M A, Rich R H, Margar-Bacal F, Cox C
Int J Pediatr Otorhinolaryngol. 1986 Feb;11(1):15-20. doi: 10.1016/s0165-5876(86)80023-4.
The characteristics of 137 patients referred to the Speech Clinic at The Hospital for Sick Children, Toronto, Canada during the past 8 years for the investigation of persistent hypernasality after adenoidectomy are reported. Over 30% of the patients had preoperative factors that are thought to increase the risk, such as submucous cleft palate, fluid regurgitation through the nose, a family history of velopharyngeal insufficiency or clefting, or hypernasality. Fifty percent of the patients required pharyngoplasty to correct hypernasality, 37% required speech therapy alone, and 13% improved with no treatment.