The velopharyngeal sphincter (which includes the soft palate and the side and back walls of the throat) separates the oral and nasal cavities during swallowing and speech. During speech, air is directed through the mouth and not the nose. In velopharyngeal insufficiency, the seal is not complete, allowing air to leak through the nose causing a hypernasal resonant voice (sounding nasally).
Velopharyngeal insufficiency can occur in people born with splitting of the roof of the mouth (cleft palate) or a palate that is too short. It can sometimes develop after tonsil or adenoid surgery or as a result of muscle weakness in people with neurological disorders such as cerebral palsy, stroke, or brain tumors. Other causes include genetic syndromes such as neurofibromatosis and tumors in the palate.
Symptoms of velopharyngeal insufficiency include a hypernasal voice with an inability to form speech sounds correctly. Severe velopharyngeal insufficiency can cause solid foods and fluids to regurgitate through the nose.
Doctors suspect velopharyngeal insufficiency in people with the typical speech abnormalities. To confirm the diagnosis, doctors inspect the velopharyngeal sphincter with a fiberoptic nasoendoscope (a flexible tube passed through the nose) or x-rays taken while swallowing different foods (videofluroscopy).
Treatment is with speech therapy and sometimes with a special device worn in the mouth or surgery.