Velopharyngeal insufficiency (VPI) is the result of an improper closing of the velopharyngeal sphincter, the soft palate muscle, during speech. When this muscle does not close properly, air escapes through the nose instead of the mouth. During speech, VPI produces a nasal quality to the voice, known as hypernasality, and a snorting sound during the pronunciation of certain letters. The condition is usually diagnosed in children, although it may be diagnosed in older patients from developing countries where early diagnosis and treatment have not been available.
Causes of Velopharyngeal Insufficiency
Velopharyngeal insufficiency may be caused by a number of conditions, including:
- Cleft palate
- Tonsil or adenoid surgery
- Nerve or muscle disease
- Weak throat muscles
- Traumatic brain injury
Almost one third of children who have surgery for cleft palate will also have persistent VPI after their palate repair. VPI may also develop after an adenoidectomy, a surgical procedure to remove adenoids or tissue in the back of the nose.
Diagnosis of Velopharyngeal Insufficiency
The hypernasal speech impediment is the primary symptom of VPI. Patients exhibiting the speech patterns associated with VPI must be examined by both a speech pathologist and an otolaryngologist for accurate diagnosis. The speech pathologist will analyze speech sounds and patterns and the otolaryngologist will assess any structural abnormalities.
Various diagnostic tests are performed by the otolaryngologist to evaluate the precise cause of the VPI and to detect the nature and location of any anatomical abnormalities. The physician will usually perform a nasopharyngoscopy, inserting a thin flexible tube fitted with a tiny fiber optic camera through the nose. This will enable to doctor to see the back of the throat where the velopharyngeal muscles are attempting to close. The doctor may also perform a videofluoroscopy of the palate and throat during speech. This test is administered after the patient has been given opaque barium nose drops to illuminate the targeted area. Another test commonly administered to patients with VPI is nasometry, which measures the output of air from the nose and mouth during speech. Sometimes an MRI scan of the the palate and throat muscles is also conducted.
Treatment of Velopharyngeal Insufficiency
Most patients can fully recovery from velopharyngeal insufficiency through a combination of surgical and nonsurgical treatments. Nonsurgical treatments for VPI include speech therapy and the use of an obturator, a modified dental retainer which alters the position of a weak palate.
Surgical methods used for treating VPI include:
- Pharyngeal flap procedure
- Furlow palatoplasty
- Augmentation pharyngoplasty
- Velopharyngeal sphincter reconstruction
After surgery, speech therapy is often necessary to change speech patterns acquired prior to the procedure.