Velopharyngeal Dysfunction (VPD)
What is VPD?
Velopharyngeal Dysfunction (VPD) is a condition where the velopharyngeal valve does not close consistently and completely during speech sound production.
Three Types of VPD
- Velopharyngeal insufficiency (VPI): a structural defect that prevents adequate velopharyngeal closure. This is the most common type of VPD, as it includes a short or abnormal velum. This occurs in children with a submucous cleft or cleft palate.
- Velopharyngeal incompetence (VPI): a neurophysical disorder which results in poor movement of the velopharyngeal structures. This is common in individuals with dysarthria due to cortical damage or velar paresis due to cranial nerve damage.
- Children with VPI may demonstrate hypernasality(too much soundin the nasal cavity), nasal air emission (leakage of airduring consonant production) and compensatory articulation productions (abnormal articulation productions in the pharynx to compensate for a lack of oral air pressure due to VPI).
- Velopharyngeal mislearning: lack of velopharyngeal closure on certain sounds due to the use of sounds in the pharynx as a substitution for certain oral sounds.
- Children with velopharyngeal mislearning may produce pharyngeal sounds as a substitute for oral sounds. This causes nasal emission due to the placement of production.
When is Speech Therapy Necessary?
- Speech therapy cannot change abnormal structure and therefore, cannot correct hypernasality or nasal emission due to VPI— even if there is only a small gap! VPI requires physical management such as surgery, or a prosthetic device.
- Speech therapy is beneficial when nasal emission or hypernasality is caused by placement errors.
What is done in Speech Therapy
- Use a “listening tube” (even a bending straw), have the child put one end of the tube in the entrance of a nostril and the other end near his ear. When nasality occurs, it is heard loudly through the tube. Ask the child to try to reduce or eliminate the sound coming through the tube as he produces oral sounds and then words.
- Bring awareness to the abnormal production versus the target sound. Give as many clues as possible using visual, tactile and auditory feedback.
- Have the child produce the phoneme /p/ and then a vowel preceded by an /h/. For example, /p…hɑ/ for /pɑ/ and /p…ho/ for /po/. This keeps the vocal folds open during transition to the vowel and prevents the production of the glottal stop.
Ashley E. MA, CF-SLP