Management of children with cleft palate and related speech disorders
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Resonance

Hypernasality

For most English sounds, the majority of acoustic energy resonates within the oral cavity. For the nasal sounds /m/, /n/ and /?/, the majority of sound resonates within the nasal cavity.

Hypernasality describes a perceptual judgment that there is excessive nasal resonance for oral sounds.

Kummer (2008) explains that "because hypernasality is due to the abnormal resonance of sounds, it is always associated with sounds that are phonated" (p. 180). Hypernasality can not occur on voiceless sounds, because these sounds do not have any acoustic energy. If voiceless sounds are perceived to be sounding nasal, then it is likely to be nasal air emission (see below), or there may be hypernasality on the vowel that precedes or follows the voiceless sound.

Henningsson et al (2008), (see further reading below, Table 2, p.6) specify guidelines for rating the severity of hypernasality along a scale of within normal limits, mild, moderate or severe. As well as considering the impact of hypernasality on intelligibility and acceptability of speech, the rating system notes the presence of hypernasality on vowels and consonants. High vowels are more vulnerable to hypernasality, as they require firmer velopharyngeal closure. Kummer (2008) explains that this is due to the high tongue position for high vowels, which reduces the space for oral resonance, and increases oral sound pressure. In cases of mild velopharyngeal inadequacy, hypernasality may only be perceived on the high vowels. Moderate hypernasality may be perceived on both high and low vowels. Hypernasality that is severe may be perceived on some voiced consonants in addition to vowels (Henningsson et al, 2008). So for example, the word "daddy" would sound more like "nanny".

Hypernasality can also result from speech motor disorders, including:

  • reduced coordination of velopharyngeal closure, as in Childhood Apraxia of Speech
  • reduced muscle tone as in dysarthria.

Note: the IPA vowel chart http://www.phonetics.ucla.edu/course/chapter1/vowels.html shows the position of the vowels – high vowels are referred to as "close" and low vowels as "open" in this chart.

 

Hyponasality

Kummer (2008) describes hyponasality as "a reduction in normal nasal resonance during speech due to blockage in the nasopharynx or nasal cavity." (p. 180). Hyponasality will be noted particularly on the nasal consonants, but may also be noticeable on vowels. This is because during the production of vowels, especially high vowels, there is some transmission of resonance through the soft palate. Perceptually, hyponasality may sound as though the speaker has a head cold, so that the word "nanny" may sound more like "daddy".

Cul-de-sac resonance is a term which is sometimes used in the literature, but does not tend to be used within our clinic.  Henningsson et al note that many clinicians have difficulty perceptually distinguishing between hyponasality and cul-de-sac resonance.

 

Mixed resonance

Any of the above types of resonance can occur in combination at different times in connected speech. For example, an individual with VPI would have predominantly hypernasal speech, noticeable on vowels and maybe some oral consonants. If that individual also had a partial blockage in the nasal cavity, then the nasal phonemes may sound hyponasal.

 

Further Reading

  • Henningsson, G., Kuehn, D.P., Sell, D., Sweeney, T., Trost-Cardamone, J. E., Whitehill, T. L., Speech Parameters Group. (2008). Universal Parameters for Reporting Speech Outcomes in Individuals with Cleft Palate. Cleft Palate-Craniofacial Journal, 45(1), 1-17. Resonance pp 6-7.
  • Kummer, A.W. (2008). Cleft Palate and Craniofacial Anomalies: Effects on Speech and Resonance (2nd ed). NY: Thomson Delmar Learning, pp 180-182.
  • Peterson-Falzone, S., Trost-Cardamone, J.E., Karnell, M. & Hardin-Jones, M. (2005). The Clinician's Guide to Treating Cleft Palate Speech. NY: Mosby, pp 19-21.

 

Disclaimer

This webpage pertains to management of children by the John Hunter Children's Hospital Cleft Palate Team.  The resource information is aimed at qualified speech pathologists working within the geographical area of the Northern Child Health Network. It assumes a working knowledge of articulation and phonological processes in paediatric populations.

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