Velopharyngeal Dysfunction (Pediatric)
What is velopharyngeal dysfunction ?
During normal speech, the palate moves to seal off the back of the nose so that the voice and sound energy are directed through the mouth for speech production. Velopharyngeal Dysfunction (VPD) refers to the lack of ability to seal off the back of the nose during speech. This results in the voice and sound energy being lost in the nose which alters the speech quality; it may also result in air emissions (snorty sounds) out of the nose, and makes the speech more difficult to be understood.
There are 3 categories of VPD:
- Velpharyngeal insufficiency. This refers to a structural or anatomical problem that prevents the patient from sealing off the back of the nose successfully during speech. The most common example is having a previously repaired cleft palate which may be short or scarred. This can occur in more than 30% of patients who have had cleft palate repair. Another common cause is a submucosal cleft palate (hidden cleft palate due to a lack of muscle in the palate). Occasionally, a patient who has undergone adenoid removal can present with velopharyngeal insufficiency, as the adenoids may sometimes assist in sealing off the back of the nose during speech.
- Velopharyngeal incompetency. This refers to a weakness of the nerves or muscles in the throat which can result in difficulty sealing off the back of the nose during speech.
- Velopharyngeal mislearning. This refers to a situation where the patient has normal anatomy, normal muscle and nerve function, and can successfully seal off the back of the nose,, but leaves the back of the nose open during the production of some speech sounds.
How is velopharyngeal dysfunction diagnosed?
VPD is usually diagnosed in a specialty clinic that is staffed by both a speech therapist and pediatric otolaryngologist (ENT) with expertise in this area. The patient is examined for any evidence of a palate abnormality. A speech therapist will perform a perceptual speech evaluation which involves carefully listening to the speech to determine if the sound is coming out of the mouth consistently, or escaping through the nose. This sometimes involves using mirrors or listening tubes to more carefully assess if any air is escaping out of the nose. The last part of the assessment is nasopharyngoscopy.
Nasopharyngoscopy is an office procedure which involves passing a small scope through the nose. The purpose of the procedure is to look at the back of the nose to see whether or not the patient is able to seal it off during speech. The scope is very narrow and is designed for young children. A small amount of numbing drops are placed in the nose prior to the procedure; nofurther anesthesia is required as the procedure causes only mild discomfort. The procedure takes 2-3 minutes. The patient may cry during the procedure, and the crying typically quickly resolves once the procedure is finished. The child can eat immediately after the procedure.
How is velopharyngeal dysfunction treated?
The treatment of VPD depends on the cause. Velopharyngeal mislearning is treated with speech therapy with very high success. Velopharyngeal insufficiency and velopharyngeal incompetency typically require surgery to help the patient seal off the back of the nose during speech. Although less common, some patients may be candidates for a prosthetic which can be worn in a similar way to a dental retainer, and can help seal off the back of the nose during speech. Even after surgery, speech therapy is typically continued.