Velopharyngeal Dsyfunction & Resonance Disorders

CODI 546 - Craniofacial Anomalies
Velopharyngeal Dysfunction & Resonance Disorders

Velopharyngeal Dysfunction: Underlying Etiology
1. Velopharyngeal Insufficiency (VPI)- Structural defect causes the velum to be short relative to the posterior pharyngeal wall
2. Velopharyngeal Incompetence (VPI) - Physiological deficiency that results in poor movement of the velopharyngeal structures
3. Velopharyngeal Mislearning - Abnormal resonance and nasal air emission without a primary velopharyngeal disorder (functional)

Causes of Velopharyngeal Insufficiency
1. History of cleft palate or submucous cleft

20% show inadequate velar length following surgical repair

Submucous cleft causes gap along midline during closure

2. Short velum or deep pharynx

Congenitally short velum
Deep pharynx due to cranial base abnormalities

3. Status Postadenoidectomy

Prior to surgery closure was velum to adenoid pad
Following surgery velum must stretch greater distance
Most adapt to changes in short time (6 wks)

Increase in velar mobility
Increase in velar height at closure
Increase in velar stretch
Increased movement of pharyngeal walls

History of cleft or submucous cleft are contraindications for adenoidectomy

4. Adenoid atrophy - Onset of VPI around puberty

5. Irregular adenoids - Deep indentation or cleft in adenoid tissue prevents tight seal & leads to nasal air emission during speech; May occur after adenoidectomy

6. Postmaxillary advancement -

Pull maxillary arch forward in relation to mandible
Improves aesthetics, articulation, nasal airway but also increases pharyngeal depth

7. Oral Cavity Tumors

8. Hypertrophic tonsils

Push velum up on one side
Restrict medial movement of lateral pharyngeal walls
Force tongue to move forward in mouth interfering with articulation of velar sounds
Tonsil projects into pharynx & prevents adequate velopharyngeal seal during speech

Causes of Velopharyngeal Incompetence
1. Abnormal muscle insertion
2. Poor lateral pharyngeal wall movement
3. Dysarthria (central or peripheral nerve damage)

Cerebral palsy, myasthenia gravis, myotonic dystrophy, neurofibromatosis, cerebral or brainstem tumors
Cranial nerve damage (IX, X, XII) causing isolated weakness of velum or pharyngeal muscles

4. Apraxia of speech - Inability to correctly time upward & downward movements during speech for oral vs nasal sounds

Velopharyngeal Mislearning
1.Faulty Articulation

Learned patterns that include posterior nasal fricative
Phoneme specific nasal air emission (PSNAE)
Posterior tongue position, limited mouth opening, low volume, reduced respiratory or articulatory effort

2. Habituated Speech Patterns
3. Lack of Auditory Feedback
4. Conversion Disorders - Learned reaction to a certain event for example following tonsillectomy

Effects of Velopharyngeal Dysfunction on Speech
1. Hypernasality

Only associated with sounds that are phonated
More perceptible on vowels
Voiced plosives sound like nasal cognates
Associated with moderate to large velopharyngeal gaps

2.Nasal air emission

Inappropriate release of air pressure through the nasal cavity
Audible as high-frequency, low intensity sound
Occurs on consonants especially high pressure sounds
Associated with fairly large opening

3. Nasal rustle (nasal turbulence)

Fricative sound that occurs as air is pushed through small velopharyngeal gap
Heard as bubbly sound at back of nose
Can be very loud and mask sound of consonant
Common on voiceless fricatives

4. Nasal snort - Forcible emission of air through the nose during consonant production producing a noisy, sneeze-like sound -associated with /s/
5. Nasal grimace
6. PSNAE
7. Weak or Omitted Consonants
8. Short Utterance Length
9. Compensatory Articulation Productions

Productions are acquired, so do respond to speech therapy
Developed in response to inadequate intraoral pressure

10. Dysphonia

Congenital abnormalities of laryngeal structures
Hyperfunction due to increased respiratory & muscular effort to close velopharyngeal port
Use of glottal stops or aggressive speech therapy to improve velopharyngeal function

Resonance Disorders
1. Hypernasality due to velopharyngeal dysfunction
2. Hyponasality usually due to obstruction
3. Cul-de-sac resonance

Blockage in vocal tract causing sound to enter cavity without a way out
Hypertrophied tonsils blocking oral cavity entrance
VPI with anterior blockage of nasal cavity

4. Mixed resonance

VPI plus significant nasal cavity or airway blockage
Oral-motor disorders with inappropriate timing

Predicting Severity of Effects on Speech
1. Co-vary with articulatory & phonatory status
2. Small VP opening can have an increased effect on quality & intelligibility
3. Moderate opening has less effect
4. Large opening usually greatest effect causing:

moderate to severe hypernasality,
weak consonants,
oral sounds nasalized or substituted by compensatory productions