Resonance Disorders

Resonance is the quality of the voice that results from sound vibrations in the throat, mouth, and nose. During normal speech, the soft palate (velum) and the throat (pharynx) muscles move to close the soft palate muscle on most sounds in the mouth. This closure keeps air from escaping through the nose. When air does escape through the nose, it can make the voice sound nasal.

Children with craniofacial disorders, particularly cleft palate, commonly have problems with the quality of their voice.

Patients can be seen by Texas Children's experts in Plastic Surgery and Speech, Language and Learning.

Causes & Risk Factors

This type of disorder can occur when the soft palate and throat do not function properly to prevent the transmission of sound into the nasal cavity.

Causes include:

  • Physical structure of the throat, mouth or nose (for example, short soft palate)
  • Movement of the throat, mouth or nose areas (for example, inadequate movement of the soft palate)
  • Inadequate learning: when a child learns to make sounds, certain sounds are pronounced incorrectly
  • A blockage that prevents sound transmission into the nasal cavity for the nasal speech sounds (m, n, and ng)

Risk factors:

  • Cleft palate
  • Enlarged adenoids
  • Craniofacial disorders

Symptoms & Types

Symptoms include:

  • Muffled speech
  • High pitched voice that cannot be understood
  • Nasal sounding voice that is hard to understand

Types include:

  • Hypernasality:
    • The voice is high pitched and can be hard to understand. This happens when too much sound comes from the nose while talking.
    • You can particularly notice this disorder on vowel sounds and voiced consonants (these are consonant sounds where the vocal cords vibrate and you can feel the vibration in your throat).
  • Hyponasality:
    • Occurs when there is a reduction in the quality of voice vibrations from the nose. This often happens because of a blockage, such as enlarged adenoids, or an obstruction in the nose.
       
  • Cul-de-sac resonance:
    • Occurs when sound is trapped in the throat, resulting in speech that sounds muffled.
    • Enlarged tonsils may cause cul-de-sac resonance.
  • Mixed resonance:
    • Occurs when there is a combination of an improper closing of the soft palate muscle and a blockage in the nasal airway.
  • Nasal air emission:
    • Occurs when there is an inappropriate release of air through the nose on a consonant sound. Nasal air emission can sometimes be heard and sometimes not.
  • Maladaptive compensatory errors:
    • Unique speech errors often seen in young children in which the soft palate muscle does not close properly while talking (called velopharyngeal insufficiency).
    • These errors develop because the child has problems with correctly pronouncing consonants.
    • These errors require speech therapy.

Diagnosis & Tests

A speech pathology evaluation includes an assessment to decide whether your child's resonance is normal.

Tests may include:

  • Computer-based tests such as pressure-flow testing and nasometry
    • These tests assess the quality of the voice that results from sound vibrations, air flow and air pressure.
  • Video x-ray (videofluoroscopy)
    • Your child is filmed while repeating words and phrases.
    • This allows the speech-language pathologist to see how the soft palate and the throat work during speech.
  • Nasoendoscopy
    • A tube with a camera is inserted through the nose while your child repeats words and phrases.
    • This allows the speech-language pathologist to see how the soft palate and the throat work during speech.

Treatment & Care

Treatment and care may include:

  • Medical and surgical interventions
  • Speech therapy
  • Prosthetic management (considered when surgery is not an option)

Other Contributors

James Carter, MA, CCC-SLP