What is VPI?
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 submucousal cleft palate, which is 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.
What Does VPI Sound Like?
The main consequences of VPI are hypernasality and nasal emission. These occur when too much sound or air comes through the nose while speaking. 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. Special tests may be recommended to help differentiate VPI. These include studies done by the radiologist and speech pathologist called videfluoroscopy. The otolaryngologist, or ear nose and throat doctor, may also perform nasoendoscopy to look inside the velopharyngeal structures.
Will Surgery Correct 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.
Occasionally, instead of surgery, an obturator is recommended to correct VPI. This special appliance is like a retainer and is fitted by the prosthodontist. It may work as a palatal lift or may have an extension called a speech bulb at its end to reduce VPI.
Is Speech Therapy Effective for VPI?
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. One common compensatory substitutions is the glottal stop, where the vocal folds try to close off air . It is like the middle sound in “kitten”. Another is pharyngeal fricative, where the tongue tries to close off air at the back of the throat. This is a hissing type sound substituted for an “s” or “z”. 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 beforephysical correction of VPI.
Children with cleft palate, just like all children, may also have other speech problems not directly related to their clefts. These problems may include other articulation errors, problems with speech timing and coordination, voice problems, and language problems. The craniofacial speech pathologist will identify these areas and make appropriate recommendations for speech therapy and further evaluation.