Matsuya T, Yamaoka M, Miyasaki T
Plast Reconstr Surg. 1979 Apr;63(4):497-500. doi: 10.1097/00006534-197904000-00010.
We studied the differences in how velopharyngeal closure is learned and obtained by operated cleft palate patients during various activities. Sixty-eight operated cleft palate patients, who had complete closure during swallowing, were examined with the nasopharyngeal fiberscope to determine the extent of velopharyngeal closure while they were producing pressure consonants or vowels, and during blowing. We concluded that the complete closure when producing vowels was the most difficult to obtain, and closure when producing pressure consonants was a little more difficult than that during blowing.