title: Preliminary study of acoustic analysis for evaluating speech-aid oral prostheses: Characteristic dips in octave spectrum for comparison of nasality.
abstract: OBJECTIVE
  Acoustic analysis is often used in speech evaluation but seldom for the evaluation of oral prostheses designed for reconstruction of surgical defect. This study aimed to introduce the application of acoustic analysis for patients with velopharyngeal insufficiency (VPI) due to oral surgery and rehabilitated with oral speech-aid prostheses.
  
  
  METHODS
  The pre- and postprosthetic rehabilitation acoustic features of sustained vowel sounds from two patients with VPI were analyzed and compared with the acoustic analysis software Praat.
  
  
  RESULTS
  There were significant differences in the octave spectrum of sustained vowel speech sound between the pre- and postprosthetic rehabilitation. Acoustic measurements of sustained vowels for patients before and after prosthetic treatment showed no significant differences for all parameters of fundamental frequency, jitter, shimmer, noise-to-harmonics ratio, formant frequency, F1 bandwidth, and band energy difference. The decrease in objective nasality perceptions correlated very well with the decrease in dips of the spectra for the male patient with a higher speech bulb height.
  
  
  CONCLUSIONS
  Acoustic analysis may be a potential technique for evaluating the functions of oral speech-aid prostheses, which eliminates dysfunctions due to the surgical defect and contributes to a high percentage of intelligible speech. Octave spectrum analysis may also be a valuable tool for detecting changes in nasality characteristics of the voice during prosthetic treatment of VPI.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Cathay General Hospital, Taipei, Taiwan; School of Medicine, Fu Jen Catholic University, Taipei, Taiwan.
authors.forename: Yen-Liang
authors.initials: YL
authors.lastname: Chang
authors.affiliation: Department of Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan; Department of Dentistry, Shin-Kong Memorial Hospital, Taipei, Taiwan.
authors.forename: Chao-Ho
authors.initials: CH
authors.lastname: Hung
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Shuang Ho Hospital, Taipei, Taiwan.
authors.forename: Po-Yueh
authors.initials: PY
authors.lastname: Chen
authors.affiliation: Chen Wei-Chang Voice Clinic, Taipei, Taiwan.
authors.forename: Wei-Chang
authors.initials: WC
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology, School of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Otolaryngology, Taipei Medical University Hospital, Taipei, Taiwan. Electronic address: seedturtle@gmail.com.
authors.forename: Shih-Han
authors.initials: SH
authors.lastname: Hung
mesh_terms: D000162:Acoustics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010158:Palatal Obturators; D013060:Speech; D014681:Velopharyngeal Insufficiency / Q000534:rehabilitation*; D014833:Voice Quality
keywords: acoustic analysis; oral prostheses; speech aid; velopharyngeal insufficiency