papers referring to vocal muscles
authors Perlman AL. Titze IR. Cooper DS.
title Elasticity of canine vocal fold tissue.
source Journal of Speech & Hearing Research. 27(2):212-9, 1984 Jun.
abbreviated source J Speech Hear Res. 27(2):212-9, 1984 Jun.
abstract Stress-strain curves were obtained from vocalis muscle tissue that was kept viable in an aerated Krebs-Ringer solution after excision of the larynx from live dogs. Results are compared to similar curves obtained from dead tissue and suggest that vocal fold elasticity depends on the level of strain, the elapsed time after elongation, the condition of the tissue, and the choice of rest length for strain computation. Tables of Young's moduli for various conditions are given.
authors Alipour-Haghighi F. Titze IR.
title Viscoelastic modeling of canine vocalis muscle in relaxation.
source Journal of the Acoustical Society of America. 78(6):1939-43, 1985 Dec.
abbreviated source J Acoust Soc Am. 78(6):1939-43, 1985 Dec.
abstract Analysis of vocal fold vibration requires information on the viscoelastic properties of the vocalis muscle. The force response of two canine vocalis muscles was measured in one-dimensional, stepwise elongation of the tissue as a function of time with a computer-controlled ergometer. The viscoelastic behavior of the muscle in its passive state was demonstrated through the relaxation test. A quasilinear viscoelastic model was used to parametrize the relaxation function, and results are reported for various levels of strain. Furthermore, a model was used to obtain theoretical time-dependent stress-strain curves to compare with experimental data.
authors Alipour-Haghighi F. Titze IR. Durham P.
title Twitch response in the canine vocalis muscle.
source Journal of Speech & Hearing Research. 30(3):290-4, 1987 Sep.
abbreviated source J Speech Hear Res. 30(3):290-4, 1987 Sep.
abstract The twitch response of the canine vocalis muscle was investigated through a series of experiments conducted in vitro. Samples of vocalis muscle were dissected and prepared from canine larynges a few minutes before death and kept in Krebs solution at a temperature of 37 +/- 1 degrees C and pH of 7.4 +/- 0.05. Field stimulation with parallel-plate silver electrodes was applied to study the twitch response of muscle samples. The peak tension and time course of isometric contraction of isolated muscle samples were measured electronically with a Cambridge Technology Dual Servo System (ergometer). Contraction time and 50% relaxation time of this muscle were measured for seven samples at various levels of strain. It was found that contraction time ranged between 22 and 32 ms and 50% relaxation time ranged between 17 and 37 ms. Results indicate that the vocalis muscle is a fast muscle capable of performing rapid maneuvers in support of changes in fundamental frequency.
authors Perlman AL. Alipour-Haghighi F.
title Comparative study of the physiological properties of the vocalis and cricothyroid muscles.
source Acta Oto-Laryngologica. 105(3-4):372-8, 1988 Mar-Apr.
abbreviated source Acta Otolaryngol (Stockh). 105(3-4):372-8, 1988 Mar-Apr.
abstract Viable tissue samples of the vocalis muscle and pars recta portion of the cricothyroid muscle were dissected from the excised larynges of middle-aged, male, mixed breed dogs. The samples were maintained in an aerated Krebs-Ringer solution and curarized. Temperature and pH were controlled. Field stimulation was performed with parallel-plate platinum electrodes. Using a dual mode ergometer, in vitro measurements were made at increased levels of strain. Least-squares regression analyses were performed on contraction times and 50% relaxation times as a function of strain. Results of this investigation indicated important differences in the active and passive properties of the pars recta portion of the cricothyroid and the vocalis muscle. The mean contraction time of the vocalis muscle was 24 ms and that of the cricothyroid muscle, 33.5 ms. The mean half relaxation time was 20 ms for the vocalis muscle and 30 ms for the cricothyroid. The twitch contraction and half relaxation times of the vocalis remained independent of strain, whereas those of the cricothyroid showed strong positive dependence on strain level. Differences in the passive properties of the two muscles were also evidenced; the vocalis muscle was found to be stiffer at all levels of strain.
authors Alipour-Haghighi F. Titze IR. Perlman AL.
title Tetanic contraction in vocal fold muscle.
source Journal of Speech & Hearing Research. 32(2):226-31, 1989 Jun.
abbreviated source J Speech Hear Res. 32(2):226-31, 1989 Jun.
abstract Active properties of canine vocalis muscle tissue were investigated through a series of experiments conducted in vitro. Samples of the vocalis muscle were dissected from dog larynges excised a few minutes before death and kept in Krebs solution at a temperature of 37 +/- 1 degree C and a pH of 7.4 +/- 0.05. Isometric and isotonic tetanic responses of the vocalis muscle were obtained electronically with a Dual Servo System (ergometer). Isometric tension was recorded at various levels of elongation and stimulation rate. Isotonic shortening was recorded at various levels of force, and shortening velocity was obtained by numerical analysis of recorded data. It was found that fused tetanus occurred at stimulation rates of about 90 Hz, where the isometric tetanic force saturates. Repeated stimulation of the muscle in vitro not only caused nonrecoverable fatigue in the tissue, but also decreased its passive tension. The combined active and passive isometric tension increased with elongation of the muscle. Results of isometric active responses were normalized with respect to average passive response. This normalization allowed for better comparison between tetanic contraction and twitch contraction. It was found that maximum tetanic contraction was 6.4 times greater than maximum twitch contraction obtained in a previous study. A tetanic contraction period was defined and investigated for eight samples of vocalis muscle tissue from different dogs. The tetanic contraction period showed a linear increasing trend with strain.
authors Alipour-Haghighi F. Perlman AL. Titze IR.
title Tetanic response of the cricothyroid muscle.
source Annals of Otology, Rhinology & Laryngology. 100(8):626-31, 1991 Aug.
abbreviated source Ann Otol Rhinol Laryngol. 100(8):626-31, 1991 Aug.
abstract Tetanic response of canine cricothyroid muscle tissue was investigated through a series of experiments conducted in vitro. Two separate portions of the cricothyroid muscle, namely the pars recta and pars oblique, were studied. Samples of the muscle were dissected from dog larynges excised a few minutes before death and kept in Krebs-Ringer solution at a temperature of 37 degrees +/- 1 degrees C and a pH of 7.4 +/- 0.05. Tetanic contraction of the muscle samples was obtained by field stimulation to the muscle through a pair of parallel-plate platinum electrodes and with a train of square pulses of 0.1-millisecond duration and 85-V amplitude. Isometric force responses of the pars recta and pars oblique muscles were obtained electronically with a dual servo system (ergometer). The effect of tissue elongation on the active and passive responses was quantified by stimulation of the sample during cyclic elongation. Both active and passive responses as a function of elongation were obtained on the same sample.
authors Alipour-Haghighi F. Titze IR.
title Elastic models of vocal fold tissues.
source Journal of the Acoustical Society of America. 90(3):1326-31, 1991 Sep.
abbreviated source J Acoust Soc Am. 90(3):1326-31, 1991 Sep.
abstract Elastic properties of canine vocal fold tissue (muscle and mucosa) were obtained through a series of experiments conducted in vitro and were modeled mathematically. The elastic properties play a significant role in quantitative analysis of vocal fold vibrations and theory of pitch control. Samples of vocalis muscle and mucosa were dissected and prepared from dog larynges a few minutes premortem and kept in a Krebs solution at a temperature of 37 +/- 1 degrees C and a pH of 7.4 +/- 0.05. Samples of muscle tissue and mucosa were stretched and released in a slow, sinusoidal fashion. Force and displacement of the samples were measured with a dual-servo system (ergometer). After digitization, stress-strain data for samples of muscle tissue and cover tissue were averaged. The stress-strain data were then fitted numerically by polynomial and exponential models.
authors Hsiao TY. Solomon NP. Luschei ES. Titze IR. Liu K. Fu TC. Hsu MM.
title Effect of subglottic pressure on fundamental frequency of the canine larynx with active muscle tensions.
source Annals of Otology, Rhinology & Laryngology. 103(10):817-21, 1994 Oct.
abbreviated source Ann Otol Rhinol Laryngol. 103(10):817-21, 1994 Oct.
abstract The relation between subglottic pressure and the fundamental frequency of vocal fold vibration was studied by means of evoked phonation in an in vivo canine model. The evoked-phonation model involved electrical stimulation of the midbrain that resulted in consistent responses by respiratory and laryngeal musculature, accompanied by phonation. The dynamic stiffness properties of the vocal folds, especially the "cover," were investigated by delivering various amounts of air pressure to the larynx from an opening in the trachea. The fundamental frequency of vocal fold vibration increased linearly with subglottic pressure. The slopes ranged from 22.4 to 118.7 Hz per kilopascal in 7 animals. The results indicated that the dependence of fundamental frequency on subglottic pressure is a passive mechanical phenomenon.
authors Story BH. Titze IR.
title Voice simulation with a body-cover model of the vocal folds.
source Journal of the Acoustical Society of America. 97(2):1249-60, 1995 Feb.
abbreviated source J Acoust Soc Am. 97(2):1249-60, 1995 Feb.
abstract A simple, low-dimensional model of the body-cover vocal-fold structure is proposed as a research tool to study both normal and pathological vocal-fold vibration. It maintains the simplicity of a two-mass model but allows for physiologically relevant adjustments and separate vibration of the body and the cover. The classic two-mass model of the vocal folds [K. Ishizaka and J. L. Flanagan, Bell Syst. Tech. J. 51, 1233-1268 (1972)] has been extended to a three-mass model in order to more realistically represent the body-cover vocal-fold structure [M. Hirano, Folia Phoniar. 26, 89-94 (1974)]. The model consists of two "cover" masses coupled laterally to a "body" mass by nonlinear springs and viscous damping elements. The body mass, which represents muscle tissue, is further coupled laterally to a rigid wall (assumed to represent the thyroid cartilage) by a nonlinear spring and a damping element. The two cover springs are intended to represent the elastic properties of the epithelium and the lamina propria while the body spring simulates the tension produced by contraction of the thyroarytenoid muscle. Thus contractions of the cricothyroid and thyroarytenoid muscles are incorporated in the values used for the stiffness parameters of the body and cover springs. Additionally, the two cover masses are coupled to each other through a linear spring which can represent vertical mucosal wave propagation. Simulations show reasonable similarity to observed vocal-fold motion, measured vertical phase difference, and mucosal wave velocity, as well as experimentally obtained intraglottal pressure.
authors Min YB. Titze IR. Alipour-Haghighi F.
title Stress-strain response of the human vocal ligament.
source Annals of Otology, Rhinology & Laryngology. 104(7):563-9, 1995 Jul.
abbreviated source Ann Otol Rhinol Laryngol. 104(7):563-9, 1995 Jul.
abstract The longitudinal elastic properties of the human vocal ligament were quantified by stress-strain measurements and by modeling the response mathematically. Human ligaments were obtained from surgery and autopsy cases. They were dissected, mounted, and stretched with a dual-servo ergometer to measure force versus elongation and to convert the results into stress and strain. To calculate a longitudinal Young's modulus, the stress-strain curves were fitted with polynomial and exponential functions and differentiated. Young's modulus was separately defined in the low- and high-strain regions. The mean Young's modulus for the low-strain region was 33.1 +/- 10.4 kilopascals. In the high-strain region, A and B parameters for an exponential fit were 1.4 +/- 1.0 and 9.6 +/- 1.2 kilopascals, respectively. The stress-strain and Young's modulus curves showed the typical hysteresis and nonlinearity seen previously in other vocal fold tissues (muscle and mucosa), but the nonlinearity was most profound for the vocal ligament.
authors Titze IR. Jiang JJ. Lin E.
title The dynamics of length change in canine vocal folds.
source Journal of Voice. 11(3):267-76, 1997 Sep.
abbreviated source J Voice. 11(3):267-76, 1997 Sep.
abstract The time courses of vocal fold elongation and contraction have been measured as a function of intrinsic laryngeal muscle activity. The superior and recurrent laryngeal nerves of anesthetized canines were stimulated supramaximally (on-off in all combinations) while the vocal folds were surgically exposed and illuminated for conventional and higher speed (300 frames per second) video recording. Microsutures were placed on various points on the vocal folds to measure elongation and contraction. Vocal fold strain, defined as elongation divided by rest length, ranged from -17% to +45%. The typical time constant for exponential increase or decrease in strain was about 30 ms. This reflects primarily the intrinsic muscle activation times rather than a passive (inertial or viscoelastic) response of cricothyroid joint rotation or translation.
authors Cox KA. Alipour F. Titze IR.
title Geometric structure of the human and canine cricothyroid and thyroarytenoid muscles for biomechanical applications.
source Annals of Otology, Rhinology & Laryngology. 108(12):1151-8, 1999 Dec.
abbreviated source Ann Otol Rhinol Laryngol. 108(12):1151-8, 1999 Dec.
abstract The geometric structure of the cricothyroid (CT) muscle and thyroarytenoid (TA) muscle was quantified in 6 human and 3 canine larynges. Each muscle was divided into a series of fiber bundles. With a 3-dimensional micrometer probe, the coordinates of the origin and insertion of each bundle were measured before dissection. It was found that the mass of the CT muscle in the dog was 1.463+/-0.280 g, which was significantly greater than the 0.9423+/-0.123 g found in the human. This was a result of the cross-sectional area of the canine CT muscle being 105.3+/-11.6 mm2 instead of the 73.8+/-7.4 mm2 found for the human. However, the ratios of CT/TA mass and cross-sectional area between the two groups were not significantly different, suggesting that the two muscles grow proportionally.
authors Alipour F. Titze I.
title Active and passive characteristics of the canine cricothyroid muscles.
source Journal of Voice. 13(1):1-10, 1999 Mar.
abbreviated source J Voice. 13(1):1-10, 1999 Mar.
abstract Active and passive characteristics of the canine cricothyroid muscle were investigated through a series of experiments conducted in vitro and compared with their counterparts in the thyroarytenoid muscle. Samples from separate portions of canine cricothyroid muscle, namely, the pars recta and pars obliqua, were dissected from dog larynges excised a few minutes before death and kept in Krebs-Ringer solution at a temperature of 37 degrees C +/- 1 degrees C and a pH of 7.4+/-0.05. Active tetanic stress was obtained in isometric and isotonic conditions by applying field stimulation to the muscle samples through a pair of parallel-plate platinum electrodes and using a train of square pulses of 0.1-ms duration and 85-V amplitude. Force and elongation of the samples were obtained electronically with a dual-servo system (ergometer). The results indicate that the dynamic response of the canine cricothyroid muscle is almost twice as slow as that of the thyroarytenoid muscle. The average 50% tetanic contraction times for pars recta and pars obliqua were 84 ms and 109 ms, respectively, in comparison to 50 ms for thyroarytenoid. The examination of force-velocity response of this muscle indicates a maximum shortening velocity of 2 to 3 times its length per second, which is about half of the thyroarytenoid shortening speed. The passive properties of the pars recta and pars obliqua portions are similar to those of thyroarytenoid muscle.