Publication detail

Computational modelling of effect of tonsillectomy on voice production

ŠVANCARA, P. HORÁČEK, J. VOKŘÁL, J. ČERNÝ, L.

Czech title

Výpočtové modelování vlivu odebrání mandlí na výslovnost

English title

Computational modelling of effect of tonsillectomy on voice production

Type

journal article - other

Language

en

Original abstract

The aim of this study is to develop mathematical 3D finite element (FE) models for numerical simulations of vibroacoustic properties of the human vocal tract after a tonsillectomy. Similar experimental studies are not easily realisable on living subjects. The FE models of the acoustic spaces corresponding to the human vocal tract for the Czech vowels /A/ and /I/ and the acoustic space around the human head were used in numerical simulations of phonation. The acoustic resonant characteristics of the FE models were studied using modal and transient analyses (excitation by a short pulse). Calculated results show that a tonsillectomy causes a frequency shift of the 3rd (~180Hz) and 4th (~120Hz) formants down to the lower frequencies for the vowel /A/ and similarly for the 2nd, 4th and 5th formants for the vowel /I/ (all ~100Hz). Similar effects and results can be found in experimental studies in literature. The formant changes are dependent on the size of additional acoustic spaces that occur after a tonsillectomy. The verification of the model was performed on the recordings of patients before and after the tonsillectomy operation. Multi-Dimensional Voice Program (MDVP Advanced, KAY Elemetrics) was used for the comparing of the formant center frequencies. Very small differences in the results of subjective evaluation of the voice before and after tonsillectomy were found.

Czech abstract

Cílem tohoto přípěvku je vytvořit matematický (3D konečněprvkový) model pro numerickou simulaci vlivu odebrání krčních mandlí (tonzilektomie) na výslovnost českých samohlásek. Obdobné experimenty s pacinty jsou obtížně realizovatelné. Byly vytvořeny MKP modely vokálních traktů pro české samohlásky /a/ a /i/ s akustickým prostorem kolem hlavy. Rezonanční charakteristiky těchto modelů byly studovány pomocí modální a přechodové analýzy (buzení krátkým pulsem). Z výsledků vyplývá, že odebrání mandlí způsobilo pro samohlásku /a/ posun třetího (~180 Hz) a čtvrtého (~120 Hz) formantu směrem k nižším frekvencím a pro samohlásku /i/ posun druhého, čtvrtého a pátého (~100 Hz) formantu také směrem dolů. Posun formantů je závislý na velikosti akustického prostoru který vznikne po odebrání mandlí. Ověření modelu bylo provedeno měřením na pacientech před a po operaci. Pro určení polohy formantů byl použit Multi-Dimensional Voice Program (MDVP Advanced, KAY Elemetrics). Při subjektivním hodnocení záznamů poslechem byl zjištěna jenom velmi malá změna.

English abstract

The aim of this study is to develop mathematical 3D finite element (FE) models for numerical simulations of vibroacoustic properties of the human vocal tract after a tonsillectomy. Similar experimental studies are not easily realisable on living subjects. The FE models of the acoustic spaces corresponding to the human vocal tract for the Czech vowels /A/ and /I/ and the acoustic space around the human head were used in numerical simulations of phonation. The acoustic resonant characteristics of the FE models were studied using modal and transient analyses (excitation by a short pulse). Calculated results show that a tonsillectomy causes a frequency shift of the 3rd (~180Hz) and 4th (~120Hz) formants down to the lower frequencies for the vowel /A/ and similarly for the 2nd, 4th and 5th formants for the vowel /I/ (all ~100Hz). Similar effects and results can be found in experimental studies in literature. The formant changes are dependent on the size of additional acoustic spaces that occur after a tonsillectomy. The verification of the model was performed on the recordings of patients before and after the tonsillectomy operation. Multi-Dimensional Voice Program (MDVP Advanced, KAY Elemetrics) was used for the comparing of the formant center frequencies. Very small differences in the results of subjective evaluation of the voice before and after tonsillectomy were found.

Keywords in English

biomechanics of voice; formant frequencies; finite element modeling of voice, tonsillectomy

RIV year

2006

Released

05.09.2006

Publisher

Taylor & Francis

ISSN

1401-5439

Volume

31

Number

3

Pages from–to

117–125

Pages count

9

BIBTEX


@article{BUT43720,
  author="Pavel {Švancara} and Jaromír {Horáček} and Jan {Vokřál} and Libor {Černý},
  title="Computational modelling of effect of tonsillectomy on voice production",
  year="2006",
  volume="31",
  number="3",
  month="September",
  pages="117--125",
  publisher="Taylor & Francis",
  issn="1401-5439"
}