Publication detail
Numerical Modelling of Effect of Tonsillectomy on Production of Czech Vowels
ŠVANCARA, P. HORÁČEK, J.
Czech title
Numerické modelování vlivu vynětí mandlí člověka na fonaci českých samohlásek
English title
Numerical Modelling of Effect of Tonsillectomy on Production of Czech Vowels
Type
journal article in Web of Science
Language
en
Original abstract
Aim of the study is to numerically examine the effect of tonsillectomy on production of Czech vowels. Similar experimental studies on living subjects are not easily realisable. The finite element (FE) models of the acoustic spaces corresponding to the human vocal tracts and acoustic space around the human head are used in numerical simulations of phonation. Models for Czech vowels /a/, /e/, /i/, /o/ and /u/ are analyzed. The acoustic resonant characteristics of the FE models are studied using modal and transient analyses (excitation by a short pulse). The production of vowels is simulated in time domain using transient analysis of the FE models excited by Liljencrants-Fants (LF) glottal signal model. Calculated results show that tonsillectomy causes frequency shifts of some formant frequencies mostly down to lower frequencies. Biggest shifts were obtained for 3rd and 4th formants for vowel /o/ ~300Hz down to lower frequencies, for 3rd (~450Hz) and 4th (~150Hz) formants for vowel /u/ and for 4th (~200Hz) formant of vowel /e/ down too. The frequency shifts of the formants are significantly dependent on position and size of the tonsils.
Czech abstract
Cílem tohoto přípěvku je analyzovat pomocí výpočtového modelování vliv odebrání krčních mandlí (tonzilektomie) na výslovnost českých samohlásek. Byly vytvořeny MKP modely vokálních traktů pro české samohlásky /a/, /e/, /i/, /o/ a /u/ s akustickým prostorem kolem hlavy člověka, umožňující pomocí přechodové analýzy s analyticky popsaným budícím signálem v úrovni hlasivek (Liljencrants-Fantův model) numerickou simulaci vyslovování těchto samohlásek. Z výsledků vyplývá, že odebrání mandlí způsobilo posun některých formantů především směrem k nižším frekvencím. Největší posun byl zjištěn pro F3 a F4 formant (-300 Hz) pro samohlásku /o/, pro F3 (-450 Hz) a F4(-150 Hz) u samohláksy /u/ a pro F4 (-200 Hz) u samohlásky/e/. Posun formantů je ovšem velice závislý nejen na velikosti mandlí, ale i na jejich poloze ve vokálním traktu.
English abstract
Aim of the study is to numerically examine the effect of tonsillectomy on production of Czech vowels. Similar experimental studies on living subjects are not easily realisable. The finite element (FE) models of the acoustic spaces corresponding to the human vocal tracts and acoustic space around the human head are used in numerical simulations of phonation. Models for Czech vowels /a/, /e/, /i/, /o/ and /u/ are analyzed. The acoustic resonant characteristics of the FE models are studied using modal and transient analyses (excitation by a short pulse). The production of vowels is simulated in time domain using transient analysis of the FE models excited by Liljencrants-Fants (LF) glottal signal model. Calculated results show that tonsillectomy causes frequency shifts of some formant frequencies mostly down to lower frequencies. Biggest shifts were obtained for 3rd and 4th formants for vowel /o/ ~300Hz down to lower frequencies, for 3rd (~450Hz) and 4th (~150Hz) formants for vowel /u/ and for 4th (~200Hz) formant of vowel /e/ down too. The frequency shifts of the formants are significantly dependent on position and size of the tonsils.
Keywords in English
biomechanics of voice; formant frequencies; finite element modeling of voice
RIV year
2006
Released
12.10.2006
Publisher
S. Hirzel Verlag
ISSN
1610-1928
Volume
92
Number
5
Pages from–to
681–688
Pages count
8
BIBTEX
@article{BUT43721,
author="Pavel {Švancara} and Jaromír {Horáček},
title="Numerical Modelling of Effect of Tonsillectomy on Production of Czech Vowels",
year="2006",
volume="92",
number="5",
month="October",
pages="681--688",
publisher="S. Hirzel Verlag",
issn="1610-1928"
}