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1.
This study tested the accuracy of indirect methods of measurementof laryngeal airway resistance in normal subjects and in spasmodic dysphonia (SD). The indirect method assumes that subglottic air pressure remains constant during the voiced segment of a syllable. In this study subglottic air pressure was directly measured via puncture of the cricothyroid membrane in seven normal subjects and seven subjects with SD. The true laryngeal airway resistance was calculated and compared with airway resistance measured using indirect techniques based on intraoral air pressure. In five of the seven normal subjects, subglottic air pressure did not remain constant during the voiced segment. As a result, the error produced using indirect method of calculating average laryngeal resistance for the normal subjects varied from −44% to +50%. For SD subjects the error ranged from −49% to +22%. In general, the indirect technique over-estimated laryngeal airway resistance in normal subjects and underestimated the resistance in subjects with SD.  相似文献   

2.
Direct measures of subglottal pressure obtained through a tracheal puncture were used to calculate laryngeal airway resistance. Six subjects completed tasks including syllable trains and more natural speech samples produced at three loudness levels. Direct calculations of natural speech resistance values were compared with indirect estimates obtained during syllable train production. The degree of correspondence between direct and indirect calculations varied by subject. Overall, the smallest relative errors among calculations occurred for syllable trains, with higher relative errors for the monologue and sentence. For loudness conditions, the smallest and largest relative errors occurred for soft and loud productions, respectively. The clinical utility of indirect estimation is questioned and suggestions for improving its validity are provided.  相似文献   

3.
Measurements on the inverse filtered airflow waveform and of estimated average transglottal pressure and glottal airflow were made from syllable sequences in low, normal, and high pitch for 25 male and 20 female speakers. Correlation analyses indicated that several of the airflow measurements were more directly related to voice intensity than to fundamental frequency (F0). Results suggested that pressure may have different influences in low and high pitch in this speech task. It is suggested that unexpected results of increased pressure in low pitch were related to maintaining voice quality, that is, avoiding vocal fry. In high pitch, the increased pressure may serve to maintain vocal fold vibration. The findings suggested different underlying laryngeal mechanisms and vocal adjustments for increasing and decreasing F0 from normal pitch.  相似文献   

4.
The purpose of this study was to compare oral pressure (Po), nasal airflow (Vn), and velopharyngeal (VP) orifice area estimates from 12 tracheoesophageal (TE) and 12 laryngeal speakers as they produced /p/ and /m/ in syllable series. The findings were as follows: (1) TE speakers produced greater Po than the laryngeal speakers; (2) for /p/, TE speakers generated Vn, and VP orifice area estimates comparable with, or less than, the laryngeal speakers; and (3) for /m/, TE speakers had Vn and VP orifice area estimates greater than the laryngeal speakers. The elevated Po could be the result of several factors such as high source driving pressures and vocal tract volume changes postlaryngectomy. Attempts at more precise articulation, and subsequently less coarticulation, by the TE speakers may explain the Vn and VP orifice area estimates for /p/ and /m/. TE speakers may be limiting the oral-nasal cavity coupling for /p/ (smaller VP gap, less Vn) in an attempt to produce a very precise oral /p/. For /m/, TE speakers may be attempting to overtly mark the consonant as a nasal (greater Vn, larger VP gap). Further studies are needed to confirm/refute the explanations postulated here regarding the VP aerodynamic differences that were identified.  相似文献   

5.
This study examined speech breathing patterns during reading bywomen with bilateral vocal fold nodules judged as mildly dysphonic and by women without vocal nodules. Although it might be predictable that the speech breathing patterns of individuals with laryngeal dysfunction will differ from those without laryngeal dysfunction, there is a lack of empirical data to support such assumptions.The results of the current study indicated that glottal airflow was greaterduring reading for the women with vocal nodules and that a larger volume of air was expended both per syllable and per breath group during reading. The rate of speech did not significantly differ between the two groups of women. There was no significant difference for the average duration of the breath groups and no significant difference for the number of syllables spoken per breath group. Additionally, both groups of women demonstrated a similar pattern of inspiratory pause location during the reading. The results suggest that speech breathing patterns associated with dysphonia be examined independently to distinguish specifically the nature of the interaction between the laryngeal dysfunction and the speech breathing pattern. Certainly, more information on how the severity of a voice disorder influences speech breathing is necessary.  相似文献   

6.
Phonation threshold pressures were directly measured in five normal subjects in a variety of voicing conditions. The effects of fundamental frequency, intensity, closure speed of the vocal folds, and laryngeal airway resistance on phonation threshold pressures were determined. Subglottic air pressures were measured using percutaneous puncture of the cricothyroid membrane. Both onset and offset of phonation were studied to see if a hysteresis effect produced lower offset pressures than onset pressures. Univariate analysis showed that phonation threshold pressure was influenced most strongly by fundamental frequency and intensity. Multiple linear regression showed that these two variables, as well as laryngeal airway resistance, most strongly predicted phonation threshold pressure. Two of the five subjects demonstrated a significant hysteresis effect, but one subject actually had higher offset pressures than onset pressures.  相似文献   

7.
The bassoon is a demanding double-reed woodwind instrument requiring exquisite control of airflow and air pressure to the reed to produce desired tonal characteristics. Little information is available from direct visualization of the vocal tract and larynx of the bassoonist while playing. Of particular interest is the mechanism(s) of vibrato. This study was undertaken to understand more fully the mechanics of the upper airway in bassoonists during music production. Four adult bassoon players served as subjects. Three players were studied with both sound-synchronized videofluoroscopy and fiber-optic nasal endoscopy. The other subject was studied only by fiber-optic endoscopy. All subjects were evaluated while playing various scales and standard passages common in music pedagogy. The results from this study revealed several findings on the mechanics of upper airway activity during playing: (1) firm velopharyngeal closure was a prerequisite for maximal containment of air pressure and regulation of airflow in the oropharyngeal regions; (2) changes in the pitch and intensity were associated with differential expansion of the pharynx; (3) tongue activity was notable because of its shaping the size and shape of the airway, its role in regulating airflow to the reed, and its contributions to conditioning airflow in vibrato; and (4) slight vocal fold displacements from subglottal airflow and epiglottic movements from tongue base activity contributed to airway changes during vibrato. These seemed to further condition subglottal pressure trains derived primarily from expiration.  相似文献   

8.
Measurements on the inverse filtered airflow waveform (the "glottal waveform") and of estimated average transglottal pressure and glottal airflow were made from noninvasive recordings of productions of syllable sequences in soft, normal, and loud voice for 25 male and 20 female speakers. Statistical analyses showed that with change from normal to loud voice, both males and females produced loud voice with increased pressure, accompanied by increased ac flow and increased maximum airflow declination rate. With change from normal voice, soft voice was produced with decreased pressure, ac flow and maximum airflow declination rate, and increased dc and average flow. Within the loudness conditions, there was no significant male-female difference in air pressure. Several glottal waveform parameters separated males and females in normal and loud voice. The data indicate higher ac flow and higher maximum airflow declination rate for males. In soft voice, the male and female glottal waveforms were more alike, and there was no significant difference in maximum airflow declination rate. The dc flow did not differ significantly between males and females. Possible relevance to biomechanical differences and differences in voice source characteristics between males and females and across loudness conditions is discussed.  相似文献   

9.
In the context of the transmission of airborne noise into an aircraft fuselage, a mathematical model for sound transmission into a thin cylindrical shell is used to study sound transmission under “flight conditions”: i.e., under conditions of external air flow past a pressurized cylinder at flight altitude. Numerical results for different incidence angles are presented for a typical narrow-bodied jet in cruising flight at 10 660 m (35 000 ft) with interior pressure at 2440 m (8000 ft). A comparison is made between no-flow sound transmission at standard conditions on the ground to sound transmission under flight conditions. It is shown that at M = 0, the cylinder transmission loss has dips at fR (cylinder ring frequency) and fc (critical frequency for a flat panel of same material and thickness as shell). Below fR cylinder resonances affect TL. Between fR and fc, cylinder TL follows a masslaw behavior. Flow provides a modest increase in TL in the mass-law region, and strongly interacts with the cylinder resonances below fR. For normally-incident waves, TL is unaffected by flow.  相似文献   

10.
High sound insulation ventilating windows (HSIVW) were recently proposed for noise control in buildings close to motorways or railways, where noise barriers are not effective or too expensive. These windows are characterized by good insulation performances and at the same time allow airflow through the window itself; such a performance matches summer indoor ventilation and refreshment needs.In the last years at the Acoustics Laboratory of the University of Perugia various prototypes were tested and their acoustic and airflow performances were assessed, also verifying the influence of filtering systems in the aerator.In the present paper a lot of experimental data are presented and in particular the results of a recent campaign, aimed at testing windows samples integrated with insulated rolling shutter boxes are presented. Sound reduction index R and single number sound reduction index Rw are evaluated, considering different exercise conditions; acoustic intensity measurements and analysis have also been performed, in order to verify the parts of the window which need to be optimized.  相似文献   

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