Velopharyngeal Insufficiency (VPI)
During normal speech, the soft palate muscle in the mouth moves up and down and touches the back of the throat. To produce oral consonants (letters such as p, w, and x), the soft palate closes against the back of the throat. When the muscle closes tightly against the back of the throat, air cannot come out the nose. Velopharyngeal insufficiency (VPI) is when the soft palate does not close tightly against the back of the throat, leading to air coming out the nose (characterized by hypernasality and/or nasal air emission) during speech. This can cause speech that is difficult to understand.
What causes VPI?
The most common cause of VPI is a cleft palate or a submucous cleft palate. About 20% of children who have a repaired cleft palate will have persistent VPI. Adenoidectomies (removal of adenoids – lymphoid tissue in the back of the nose) can occasionally result in VPI by creating more space between the soft palate and the back of the throat. Usually VPI that occurs after an adenoidectomy is temporary, improving after a few weeks, and rarely persisting long-term.
Children with velocardiofacial syndrome (DiGeorge syndrome) can have VPI even if they do not have an obvious cleft palate. Traumatic brain injuries or neurological disorders can also result in velopharyngeal incompetence due to muscle weakness or difficulty with muscle coordination of the palate. In some cases, VPI results from an unknown cause.
How is VPI diagnosed?
A speech pathologist can determine whether the speech deficit is caused by VPI or another speech disorder. A nasoendoscopy is used to view palatal motion during speech and to determine the size and shape of the velopharyngeal gap. A small flexible fiberoptic scope is inserted into the child’s nose to observe how the palate moves while the child is talking. The image helps the otolaryngologist, speech pathologist and plastic surgeon decide on treatment recommendations.
How is VPI treated?
Children with VPI often produce sounds incorrectly and speech therapy is recommended to help them pronounce sounds properly. Research has shown that blowing bubbles and using oral-motor exercises are not effective for improving velopharyngeal function.
Surgery is commonly needed to improve VPI. The most common types of surgery for VPI are furlow palatoplasty, sphincter pharyngoplasty, pharyngeal flap, or a posterior pharyngeal wall injection augmentation. The size and shape of the velopharyngeal gap will dictate the type of surgery that is necessary. A speech evaluation is recommended approximately six weeks after surgery to re-evaluate speech and determine if therapy is recommended.