A video-fiberscopic study of laryngopharyngeal behaviour in the human beatbox.

The human beatbox is the art of reproducing all types of sounds with the mouth while 'adapting' them for better control. To understand how these 'voice virtuosos' juggle with so many different sounds--instrumental, rhythmic, and vocal--at the same time, we have performed a descriptive analysis of three beatboxers by observing their vocal tract behaviour by fiberscopic imaging using an OCM visual scale. From an anatomical-dynamic point of view, beatboxers mobilize all the structures of their laryngopharynx separately. With this first physiological study of the human beatbox, we could observe a well-developed laryngopharyngeal system with extreme articulatory configurations to perform their art.

Long-term acoustic comparison of thyroplasty versus autologous fat injection.

OBJECTIVES: Medialization by thyroplasty or intracordal autologous fat injection provides voice improvement in patients with unilateral vocal fold paralysis. Thyroplasty is considered a "permanent" medialization, whereas fat injection is considered "temporary" because of reabsorption. The objective of this study was to compare the evolution of acoustic parameters for these procedures over 1 year and to evaluate the results of fat injection at 2 years. METHODS: From 1994 to 1998, 46 consecutive patients (17 women and 29 men) were treated exclusively by intracordal injection of autologous fat, and then from 1999 to 2002, 48 consecutive patients (19 women and 29 men) were treated with the Montgomery Thyroplasty Implant System or Gore-Tex thyroplasty. Each patient's voice was prospectively recorded before operation and at 1,3, 12, and 24 months after operation. Six patients (13%) in the injection group underwent a second injection, and 1 patient (2%) in the thyroplasty group underwent revision surgery. Jitter, shimmer, and noise-to-harmonics ratio (NHR) were calculated for a 1000-ms midvowel segment of the vowel /a/. RESULTS: One month after operation, jitter, shimmer, and NHR were significantly improved in both groups (Wilcoxon's test, p < 0.05 in all cases). Jitter and shimmer did not change significantly between 1 and 3 months or between 1 and 12 months (p > 0.05). The NHR had improved at 12 months in both groups (injection, p = 0.0004; thyroplasty, p = 0.0178) and at 24 months in the injection group (p = 0.0076). No significant difference was noted between the two techniques before operation or at 1, 3, or 12 months after operation (Mann-Whitney test, p > 0.05). Jitter and shimmer had not changed significantly after 24 months in either group. At 24 months, there was no difference in acoustic parameters between the two treatment groups. CONCLUSIONS: The two techniques provided comparable objective acoustic voice improvement. At 2 years, autologous fat injection provides long-term acoustic voice improvement comparable to that of thyroplasty, but it has a higher rate of revision surgery.

Vocal tract area function for vowels using three-dimensional magnetic resonance imaging. A preliminary study.

OBJECTIVE: To assess whether magnetic resonance imaging (MRI) allows the vocal tract (VT) area function to be determined for a normal male speaker. METHOD: VT shapes were acquired using MRI during sustained production of French points vowels: /i/, /a/, /u/. Cross-sectional areas were measured from a series of planes spaced at intervals of 1 cm along the length of the VT and were used as input in a previously described VT model to simulate the vowels. The first three formant frequencies, F1, F2, and F3, computed from the MRI-measured VT model were compared with subject's natural formant frequencies. RESULTS: Including piriform sinuses, calculated formants differed from measured formants F1, F2, and F3, respectively, for /i/ by -3.5%, +7.7%, and +27.5%; for /a/ by +11% +19.5%, and -4.3%; and for /u/ by +.9%, +23.4%, and +9.6%. Excluding piriform sinuses, calculated formants differed from measured formants F1, F2, and F3, respectively, for /i/ by -3.5%, +12%, and +28%, and for /u/ by +10.1%, +26.8%, and +13.7% The piriform sinuses were not visualized for /a/ on MRI. CONCLUSIONS: MRI is a noninvasive technique that allows VT imaging and determination of VT area function for a normal male speaker. Several possible sources of discrepancies are as follows: variability of the articulation, difficulties in assessment of VT wall boundaries, role of the piriform sinuses, and VT length.

Fundamental frequency histograms measured by electroglottography during speech: a pilot study for standardization.

This study was designed to develop a database for the electroglottographic measurement of fundamental frequency (Fo) in normal subjects in running speech, for reference in the diagnosis and follow-up of dysphonic patients. A prospective pilot study included 20 healthy male volunteers without laryngeal disorder. Electroglottographic recordings of speaking Fo during connected speech (French) were obtained from two texts with different prosodic content. Fo histograms were sensitive to the variation of speaking Fo between both texts. Graphic representation of the range and distribution of the Fo of the speaker were designed as normalized Fo histograms with plot lines at 5th and 95th percentiles. Less than 5% variability of Fo histograms was recorded when recording more than 15 subjects. This pilot study designed a graphic display of standardized electroglottographic Fo measurements during the physiological condition of connected speech. As the degree of Fo variability depends on the phonetic contents of the text and on the language spoken, a separate histogram for normal subjects needs to be developed in each country or at least for each voice laboratory, with a standard, previously chosen text.

Phonetic effects of paralytic dysphonia.

OBJECTIVES: This study was performed to determine whether and how unilateral vocal fold paralysis (UVFP) affects the production and perception of voiced stop consonants as compared with unvoiced stops, and to analyze the phonetic effects of UVFP on the voicing feature. METHODS: Phonetic constructs pronounced by 7 male patients with UVFP and 5 normal male subjects were recorded. The 432 speech tokens consisted of intervocalic, prevocalic, and postvocalic stop consonants (/p/, /t/, /k/, /b/, /d/, /g/) in the vowel contexts /a/ and /i/. Perceptual consonant identification testing was performed with 5 voice and speech professionals as listeners. The type and frequency of errors made in consonant identification were analyzed. Spectrographic analysis was used to analyze acoustic cues. RESULTS: The rate of correct consonant identification was significantly lower for tokens pronounced by patients with UVFP (77.3% versus 97.6%, p = .0001) because of incorrect identification of the voiced consonants, frequently perceived as their unvoiced homologues. Confusion between dental and alveolar place of articulation for unvoiced stops was also noted. CONCLUSIONS: Unilateral vocal fold paralysis alters the voiced-unvoiced stop consonant distinction and the dental-palatal stop consonant distinction in an experimental nonspeech context. This finding implies the existence of a phonetic handicap for patients with UVFP. Further studies should determine the effects of UVFP on global speech intelligibility.

Laryngeal aerodynamics after vocal fold augmentation with autologous fat vs thyroplasty in the same patient.

OBJECTIVE: To analyze laryngeal aerodynamics in the same patient in 4 different circumstances: before the onset of unilateral vocal fold paralysis (UVFP), after the onset of UVFP, and after 2 types of surgical vocal fold medialization techniques to compare the results of surgery with the measurements made in that same patient when his larynx was healthy (before paralysis). DESIGN: Prospective self-paired study of 1 male patient. Measurements were taken before iatrogenic UVFP (of the patient's healthy larynx), 1 week after the onset of iatrogenic UVFP (thoracic surgery), 3 days after vocal fold medialization with autologous fat, and 2 months after polytetrafluoroethylene thyroplasty. SETTING: University hospital. MAIN OUTCOME MEASURE: Phonatory airflow and intraoral pressure. RESULTS: Airflow and intraoral pressure increased after the onset of UVFP. Airflow decreased to preparalytic values after both types of vocal fold medialization. Intraoral pressure decreased after fat injection but increased after thyroplasty, despite the favorable effects of this treatment on laryngeal resistance and vocal efficiency compared with preparalytic values. CONCLUSIONS: Our study demonstrates the variability of intraoral pressure as an indirect measure of subglottal pressure after vocal fold medialization in UVFP, due to as yet unknown factors. Phonatory airflow, laryngeal resistance, and vocal efficiency seem to be more reliable indicators of aerodynamic results after vocal fold medialization.

Acoustic analysis of autologous fat injection versus thyroplasty in the same patient.

We objectively measured the acoustic effects of treatment of unilateral vocal fold paralysis by injection of autologous fat and by polytetrafluoroethylene thyroplasty, in the same patient. To our knowledge, this is the first report comparing the two techniques by using the patient's normal voice as the control. The voice of a male patient was recorded before and after onset of unilateral vocal fold paralysis, after treatment with autologous fat, and after polytetrafluoroethylene thyroplasty. Acoustic analysis was performed on a long-term average spectrum of text and on the MDVP (Kay Elemetrics) evaluation of the vowel /a/. Jitter and shimmer were not normalized, but they improved to a greater extent after fat injection. The cepstral peak prominence, spectral skewness, and long-term average spectrum returned to preparalytic values after both treatments, but improved to a greater extent after fat injection. This study showed that both techniques can return the voice to preparalytic values. Spectral measurements best reflected the voice improvement. Further prospective studies in a larger number of patients will be necessary to confirm these results and to determine the long-term objective voice outcome obtained with these techniques.

Objective acoustic and aerodynamic measures of breathiness in paralytic dysphonia.

This study was designed to determine which objective acoustic or aerodynamic parameters allowed a homogeneous group of patients with unilateral vocal fold paralysis (UVFP) to be distinguished from an age-matched and smoking-matched control group and to search for linear correlations between the objective parameters and the subjective breathiness ratings. Eight patients with recent-onset UVFP and 12 controls were prospectively studied. The acoustic parameters measured for the vowel /a/ at a comfortable frequency and intensity were: jitter, shimmer, harmonics-to-noise ratio, cepstral peak prominence, the difference between the levels of the first two harmonics and the relative energy above 6 kHz. Aerodynamic parameters included the mean flow rate during a sustained /a/ and intraoral pressure during the production of the phoneme /pi/. The long-term average spectrum was calculated for 40 s of text, and the relative average energies in four frequency bands were compared. Six judges rated a mid-/a/ sample using a five-parameter scale with four levels of severity. Nonparametric statistical analysis revealed significant differences ( P<.05) between the UVFP group and the control group for 14 of the 19 parameters studied. Correlations between the objective parameters and perceived breathiness differed in the two groups. Correlations were not always as expected as based on previous literature reports. These measurements provided an objective qualification of voice in patients with UVFP and successfully distinguished them from the normal controls. The objective acoustic and aerodynamic measurements had generally low linear correlations with breathiness ratings in the control group. Higher correlations were seen in the UVFP group, in which breathiness was best correlated with airflow measurements.