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Observation and analysis of in vivo vocal fold tissue instabilities produced by nonlinear source-filter coupling: A case studya)
a)Portions of this work were presented at the 157th meeting of the Acoustical Society of America in Portland, OR, in May 2009.
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10.1121/1.3514536
/content/asa/journal/jasa/129/1/10.1121/1.3514536
http://aip.metastore.ingenta.com/content/asa/journal/jasa/129/1/10.1121/1.3514536

Figures

Image of FIG. 1.
FIG. 1.

High-speed video measurement and data acquisition system. Setup 1: complete system and flexible endoscopy through a modified CV mask are shown. Real time data visualization is displayed for convenience of the clinician and system operator.

Image of FIG. 2.
FIG. 2.

Endoscopic view obtained with (a) flexible endoscope and (b) rigid endoscope. White horizontal lines indicate the locations of the three selected DKGs. The white vertical line indicates the glottal midline.

Image of FIG. 3.
FIG. 3.

Acoustically induced bifurcation. Downward pitch glide for vowel /i/ using setup 1: (a) normalized microphone signal, (b) microphone spectrogram, (c) normalized accelerometer signal, and (d) accelerometer spectrogram. Upper arrows bound the register transition section to be further analyzed in Fig. 7. Lower arrows bound a less periodic region in the signals after the bifurcation point.

Image of FIG. 4.
FIG. 4.

Source-induced bifurcation. Upward pitch glide for vowel /ae/ using setup 2: (a) normalized microphone signal, (b) microphone spectrogram, (c) normalized accelerometer signal, and (d) accelerometer spectrogram. Upper arrows bound the register transition section to be further analyzed in Fig. 8. Lower arrows bound a region with increased harmonic amplitude prior to the bifurcation point.

Image of FIG. 5.
FIG. 5.

Snapshot sequence of voice break for vowel /i/. Time is represented from left to right and spans 10 ms per row with a 250 μs period between subsequent frames. The middle row depicts the register transition. The time interval in this HSV sequence is also shown in Fig. 7.

Image of FIG. 6.
FIG. 6.

Snapshot sequence of voice break for vowel /ae/. Time is represented from left to right and spans 10 ms per row with a downsampled 400 μs period between subsequent frames for visualization purposes. The middle row primarily depicts the register transition. The time interval in this HSV sequence is also shown in Fig. 8.

Image of FIG. 7.
FIG. 7.

Acoustically induced bifurcation. Synchronous plots for vowel /i/ selected from the interval indicated in Fig. 3: (a) microphone, (b) accelerometer, (c) derivative of electroglottograph, (d) oral volume velocity, (e) glottal area, (f) anterior, middle, and posterior kymograms, and (g) phonovibrogram. All signals normalized. The normalized PVG grayscale indicates maximum amplitude in white. Upper arrows bound the bifurcation region shown in the HSV sequence of Fig. 5. Reduced vocal fold contact, parallel vocal fold motion, and increased glottal excursion followed by a sudden register transition are observed in this region. Most signals exhibit an aperiodic component after the bifurcation.

Image of FIG. 8.
FIG. 8.

Source-induced bifurcation. Synchronous plots for vowel /ae/ selected from the interval indicated in Fig. 4: (a) microphone, (b) accelerometer, (c) derivative of electroglottograph, (d) glottal area, (e) anterior, middle, and posterior kymograms, and (f) phonovibrogram. All signals normalized. The PVG grayscale indicates maximum amplitude in white. Upper arrows bound the bifurcation region shown in the HSV sequence of Fig. 6. Reduced vocal fold contact and transitional appearance of an additional glottal pulse are observed in this region.

Tables

Generic image for table
TABLE I.

Pitch glides exhibiting voice instabilities for case study subject. Instances with HSV are denoted by (*) and (**), where the latter were used for post-processing. The experimental setup used for each recording is stated. Notation: F 0 is the fundamental frequency either before or after the instability, F 1 and F 2 are the vocal tract formant frequencies, and F 1sub and F 2sub are the frequencies of subglottal resonances. The labeling for F 0F 1 crossings was defined when the pitch was within the bandwidth of the first vocal tract formant (labeled as “supra”), the first subglottal resonance (labeled as “sub”), or outside of them (labeled as “no”).

Generic image for table
TABLE II.

Frequency jumps in Table I indicating bifurcations, where average (mean) and standard deviation (SD) of fundamental frequency (F 0) are taken across all setups. Dashes under SD mean that only one instance was observed for the case. Hysteresis in F 0 is observed with respect to the direction of the pitch glide.

Generic image for table
TABLE III.

HSV measures taken from two DKGs representing middle and posterior tissue motion during chest and falsetto registers. Average (mean) and standard deviation (SD) are obtained from 25 to 50 ms HSV samples for each case. The chest register in vowel /i/ exhibits the largest SDs with respect to the mean values for all measures.

Generic image for table
TABLE IV.

Cumulative sum of the first five relative EOF weights for each vowel both before and after the voice breaks. The first values above a 97% threshold are underlined to define the number of significant modes needed for the reconstruction. S tot is the information entropy representing irregularity and broadness of the mode distribution for each case. The chest register in vowel /i/ exhibits the broadest distribution and largest number of significant modes.

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/content/asa/journal/jasa/129/1/10.1121/1.3514536
2011-02-02
2014-04-20
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752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Observation and analysis of in vivo vocal fold tissue instabilities produced by nonlinear source-filter coupling: A case studya)
http://aip.metastore.ingenta.com/content/asa/journal/jasa/129/1/10.1121/1.3514536
10.1121/1.3514536
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