Velopharyngeal dysfunction (VPD) is a general term. It is used to describe different disorders of the velopharyngeal valve, including:
- velopharyngeal insufficiency (VPI)
- velopharyngeal incompetence (VPI)
- velopharyngeal mislearning
Figure 1 shows velopharyngeal insufficiency, which is caused by an abnormality of the structures. Velopharyngeal insufficiency is common in children with a history of cleft palate or a submucous (under the skin) cleft. Sometimes, subtle signs of a submucous cleft can be seen when looking in the mouth. However, the abnormality may only be visible by putting a scope in the nose and looking at the top side of the velum.
Velopharyngeal insufficiency can also occur after adenoidectomy, although the incidence is rare (about 1 in 2,500 cases). This is because the adenoids are right in the area of normal velopharyngeal closure. Figure 2 shows the position of the adenoid pad in the throat.
Figure 3 shows velopharyngeal incompetence, which is caused by poor movement of the velopharyngeal structures. The inadequate movement of the velopharyngeal structures is usually due to a neurological disorder or injury (as in cerebral palsy or traumatic brain injury).
Some children have a form of velopharyngeal dysfunction called velopharyngeal mislearning. In this case, the velopharyngeal valve does not close appropriately during speech because the child has not learned to use it correctly.