title: The effect of sound intensity on velopharyngeal function in normal individuals.
abstract: OBJECTIVE
  Velopharyngeal closure is an important physiological process contributing to the normal function of speech and swallowing. The aim of this study was to analyze the influence of sound intensity on velopharyngeal function in normal individuals.
  
  
  METHODS
  Lateral cephalograms of 38 volunteers obtained at rest and during phonation of vowel /i:/ at both high and low sound intensity were carefully analyzed. The digital sound level meter was used to evaluate and record the sound intensity of the phonation process. The angular and linear parameters on the lateral cephalograms were then measured to reveal the correlation between sound intensity and velopharyngeal closure.
  
  
  RESULTS
  All the angular parameter values measured in the study were significantly greater in high sound intensity condition. As for linear parameters, all values were found to be significantly larger at high sound intensity, except for the effective velopharyngeal length and the vertical velopharyngeal length. A multiple linear regression model was set up to describe the correlation between the sound intensity, the effective velopharyngeal length, and velopharyngeal closure. With the increase of sound intensity and the decrease of the effective velopharyngeal length, the width of velopharyngeal closure is enlarged.
  
  
  CONCLUSIONS
  As one of the characteristic features of sound wave, the sound intensity was found to affect the objectively measured parameters of velopharyngeal closure on lateral cephalograms.
authors.affiliation: State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province China.
authors.forename: Meng
authors.initials: M
authors.lastname: Jiang
authors.affiliation: Department of Oral and Maxillofacial Radiology, Nanjing Stomatological Hospital, Nanjing, Jiangsu Province, China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province China.
authors.forename: Bin
authors.initials: B
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province China.
authors.forename: Meng
authors.initials: M
authors.lastname: You
authors.affiliation: State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province China. Electronic address: wanghu200108@163.com.
authors.forename: Hu
authors.initials: H
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D016014:Linear Models; D008297:Male; D010699:Phonation; D011859:Radiography; D055158:Velopharyngeal Sphincter / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult
keywords: Lateral cephalogram; Sound intensity; Velopharyngeal closure