In normal American speech, most consonants and vowels are produced through the mouth, or oral cavity, and require no or very little airflow through the nose. The only consonants produced through the nose are “m”,”n”, and “ng”. The muscles of the palate and the throat work together and close off the nasal area from the oral area to provide the right balance for normal sounding speech. This is known as velopharyngeal closure. If the velopharyngeal sphincter does not close properly, air escapes through the nose instead of the mouth. This is known as VPI, or velopharyngeal insufficiency. This physical problem may be due to poor movement of the palate, a palate which is not long enough to reach the back wall of the throat, an open cleft palate, or a submucosal cleft palate (a cleft covered by the tissue lining the roof of the mouth). The goal of the surgeon during palate repair is to close the palate and ensure good speech quality. About 25% of children with cleft palate, with or without cleft lip, may have VPI after palate repair.
The main consequences of VPI are hypernasality and nasal emission. Speech sounds too nasal or muffled, and other sounds may be heard including snorts and squeaks. It is very important that the speech pathologist on the craniofacial team evaluate your child’s speech to identify VPI. There are other speech problems which may exist along with or instead of VPI.
The surgeon and speech pathologist will review test results and determine the best approach to correct VPI. If surgery is recommended, there are different surgeries to consider, including palatoplasty, pharyngeal flap, and sphincter pharyngoplasty.
Other speech problems may exist which are related to VPI and often affect articulation, the way children produce their speech sounds. Children may try to compensate for their VPI and develop unusual speech consonants known as compensatory substitutions. Children unconsciously try to produce sounds orally and stop the air before it leaks into the nose. These error patterns quickly become habits and are very difficult to change if not corrected by speech therapy. Speech therapy may not completely correct VPI symptoms but should be started as soon as possible, even before physical correction of VPI.