The most definitive test to document the presence of a velopharyngeal insufficiency (VPI) is a nasopharyngoscopy (or nasoendoscopy). Nasoendoscopy is an important tool often used to assess the structure of the soft palate (velum) and its function. The scope can be placed in the nose and allows the speech-language pathologist to assess dynamic function during various speech tasks. This test provides definitive findings that can be used by the otolaryngologist and the speech-language pathologist to assess resonance disorders, and to make decisions about how to help the patient establish better intelligibility and a more balanced resonance.
Resonance disorders may be the result of an anatomical difference or defect found often in cleft lip and palate disorders. Either too much air escapes through the velopharyngeal port and out the nose, resulting in hypernasality or “nasal” speech, or not enough, resulting in hyponasality, where the individual will sound as if he has a cold. Children born with cleft lips and/or cleft palates will most often have hypernasal speech because excessive amounts of air escape through the nose during talking. These various resonance disorders negatively impact how understandable an individual is, and so it is important to test the severity of the hypernasality or hyponasality in order to decide how to address this problem.
Cleft lips and cleft palates are relatively uncommon facial defects which occur roughly in one in 700 births in North America annually. Clefts of the lip or of the palate are a separation of the sides of the mouth, the lip or the roof of the mouth. This physical split, in any of these three areas, makes it difficult to direct airflow through the mouth and away from the nose. These splits in the lip or in the palate make it difficult to separate the mouth from the nose and so excessive airflow escapes through the nose during speech, resulting in hypernasality. This hypernasality negatively affects the clarity of speech and how nasal a person may sound.