Vowel Harmonic Amplitude Differences in Persons With Vocal Nodules

Background

Spectrum is a fast Fourier transform-generated power spectrum extracted from the speech sample. It is reported to provide a quantitative acoustic index of the degree of glottal abduction and adduction in voices perceived to be breathy or pressed. In the present study, it was hypothesized that there would be abnormal reduction of higher harmonic amplitudes relative to the amplitude of the first harmonics in the subjects with vocal nodules and hence the present study was carried out.

Method

One hundred twenty participants were divided into clinical group and control group. They were instructed to phonate /a/ at their most comfortable pitch and loudness. Fourier transformation of the recorded acoustic signal was first performed to create a spectrum. Amplitudes were measured for the first and second harmonics (H1 and H2) as well as the harmonics at the first, second, and third formants (A1, A2, and A3) using the Computerized Speech Science Lab (Kay Pentax, Lincoln, NJ).

Results

There was a significant difference between the means of two groups for all the parameters, such as H1-H2, H1-A1, H1-A2, and H1-A3 at P < 0.05. The obtained results are discussed with respect to the underlying pathophysiology.

Conclusions

The present study investigated the vowel harmonic amplitude differences in persons with vocal nodules. The results revealed a significant difference between the two groups for the vowel harmonic amplitude differences. This particular measure could be used to track the changes following the vocal treatment.     

Perceptual sensitivity to first harmonic amplitude in the voice source

Little is known about the perceptual importance of changes in the shape of the source spectrum, although many measures have been proposed and correlations with different vocal qualities (breathiness, roughness, nasality, strain...) have frequently been reported. This study investigated just-noticeable differences in the relative amplitudes of the first two harmonics (H1-H2) for speakers of Mandarin and English. Listeners heard pairs of vowels that differed only in the amplitude of the first harmonic and judged whether or not the voice tokens were identical in voice quality. Across voices and listeners, just-noticeable-differences averaged 3.18 dB. This value is small relative to the range of values across voices, indicating that H1-H2 is a perceptually valid acoustic measure of vocal quality. For both groups of listeners, differences in the amplitude of the first harmonic were easier to detect when the source spectral slope was steeply falling so that F0 dominated the spectrum. Mandarin speakers were significantly more sensitive (by about 1 dB) to differences in first harmonic amplitudes than were English speakers. Two explanations for these results are possible: Mandarin speakers may have learned to hear changes in harmonic amplitudes due to changes in voice quality that are correlated with the tones of Mandarin; or Mandarin speakers' experience with tonal contrasts may increase their sensitivity to small differences in the amplitude of F0 (which is also the first harmonic).     

Influence of Speaker Gender on Listener Judgments of Tracheoesophageal Speech

The objectives of this prospective and exploratory study are to determine: (1) na?ve listener preference for gender in tracheoesophageal (TE) speech when speech severity is controlled; (2) the accuracy of identifying TE speaker gender; (3) the effects of gender identification on judgments of speech acceptability (ACC) and naturalness (NAT); and (4) the acoustic basis of ACC and NAT judgments. Six male and six female adult TE speakers were matched for speech severity. Twenty na?ve listeners made auditory-perceptual judgments of speech samples in three listening sessions. First, listeners performed preference judgments using a paired comparison paradigm. Second, listeners made judgments of speaker gender, speech ACC, and NAT using rating scales. Last, listeners made ACC and NAT judgments when speaker gender was provided coincidentally. Duration, frequency, and spectral measures were performed. No significant differences were found for preference of male or female speakers. All male speakers were accurately identified, but only two of six female speakers were accurately identified. Significant interactions were found between gender and listening condition (gender known) for NAT and ACC judgments. Males were judged more natural when gender was known; female speakers were judged less natural and less acceptable when gender was known. Regression analyses revealed that judgments of female speakers were best predicted with duration measures when gender was unknown, but with spectral measures when gender was known; judgments of males were best predicted with spectral measures. Na?ve listeners have difficulty identifying the gender of female TE speakers. Listeners show no preference for speaker gender, but when gender is known, female speakers are least acceptable and natural. The nature of the perceptual task may affect the acoustic basis of listener judgments.     

Multidimensional analyses of voicing offsets and onsets in female speakers

This study investigates cross-speaker differences in the factors that predict voicing thresholds during abduction-adduction gestures in six normal women. Measures of baseline airflow, pulse amplitude, subglottal pressure, and fundamental frequency were made at voicing offset and onset during intervocalic /h/, produced in varying vowel environments and at different loudness levels, and subjected to relational analyses to determine which factors were most strongly related to the timing of voicing cessation or initiation. The data indicate that (a) all speakers showed differences between voicing offsets and onsets, but the degree of this effect varied across speakers; (b) loudness and vowel environment have speaker-specific effects on the likelihood of devoicing during /h/; and (c) baseline flow measures significantly predicted times of voicing offset and onset in all participants, but other variables contributing to voice timing differed across speakers. Overall, the results suggest that individual speakers have unique methods of achieving phonatory goals during running speech. These data contribute to the literature on individual differences in laryngeal function, and serve as a means of evaluating how well laryngeal models can reproduce the range of voicing behavior used by speakers during running speech tasks.     

Glottal characteristics of male speakers: acoustic correlates and comparison with female data.

Acoustic measurements believed to reflect glottal characteristics were made on recordings collected from 21 male speakers. The waveforms and spectra of three nonhigh vowels (/ae, lambda, epsilon/) were analyzed to obtain acoustic parameters related to first-formant bandwidth, open quotient, spectral tilt, and aspiration noise. Comparisons were made with previous results obtained for 22 female speakers [H. M. Hanson, J. Acoust. Soc. Am. 101, 466-481 (1997)]. While there is considerable overlap across gender, the male data show lower average values and less interspeaker variation for all measures. In particular, the amplitude of the first harmonic relative to that of the third formant is 9.6 dB lower for the male speakers than for the female speakers, suggesting that spectral tilt is an especially significant parameter for differentiating male and female speech. These findings are consistent with fiberscopic studies which have shown that males tend to have a more complete glottal closure, leading to less energy loss at the glottis and less spectral tilt. Observations of the speech waveforms and spectra suggest the presence of a second glottal excitation within a glottal period for some of the male speakers. Possible causes and acoustic consequences of these second excitations are discussed.     

Spastic/spasmodic vs. tremulous vocal quality: motor speech profile analysis

Strained, strangled, and tremulous vocal qualities that are typically seen in adductor spasmodic dysphonia (ADSD), voice tremor (Tremor), and the spastic dysarthria of amyotrophic lateral sclerosis (ALS) may sound similar and be difficult to differentiate. The purpose of this study was to determine if these vocal qualities of neurologic origin could be differentiated on the basis of acoustic and motor speech parameters. Three groups of subjects (ADSD, ALS, and Tremor) were analyzed by the Motor Speech Profile System (Kay Elemetrics, Lincoln Park, NJ) for fundamental frequency (Fo), standard deviation of Fo, diadochokinetic rate (ddk), standard deviation of ddk, mean intensity and standard deviation of ddk, frequency and amplitude variability in connected speech, and speaking rate in connected speech. Profiles of the three groups are presented with the significant features that differentiated one from the other.     

激光脉宽对谐波频移和振幅强度的影响

数值研究了激光脉宽对H_2~+和T_2~+谐波辐射的影响.计算结果表明:(i)对于谐波频移现象:在少周期激光场下,H_2~+和T_2~+谐波辐射呈现红移.随着激光脉宽增大,H_2~+谐波辐射呈现蓝移; T_2~+谐波辐射红移减弱.(ii)对于谐波振幅强度:H_2~+和T_2~+谐波辐射强度会随着激光脉宽增大而增强.但是,在少周期激光场下,H_2~+谐波截至能量附近的强度要大于T_2~+.在多周期激光场下,T_2~+谐波截至能量附近的强度要大于H_2~+.     

Adductor spasmodic dysphonia and muscular tension dysphonia: Acoustic analysis of sustained phonation and reading

Acoustic phonatory events were identified in 10 women diagnosed with adductor spasmodic dysphonia (ADSD) and compared to 5 women and 5 men diagnosed with muscle tension dysphonia (MTD). The three acoustic parameters examined during sustained vowel production and reading included phonatory breaks, aperiodicity, and frequency shifts. Intra- and intermeasurer correlations showed high reliability for the measures. Findings indicated that those with ADSD produced a greater number of aberrant acoustic events than those with MTD. The results suggested that: (1) only those with ADSD show evidence of phonatory breaks during vocalization, albeit a sustained vowel or voicing during reading; (2) those with ADSD demonstrate greater variation in the type of aberrant acoustic events produced as a function of speech task. The latter point suggests that control of the larynx varies as a function of task demand, a finding not evident in the functionally based disorder of MTD. MTD is a disorder that often presents itself in a similar clinical manner to ADSD because of its perceptual commonalties and resembling laryngoscopic characteristics. The acoustic analysis presented in this study could be used as a method to assist in distinguishing between the two disorder types.     

Loudness predicts prominence: fundamental frequency lends little

We explored a database covering seven dialects of British and Irish English and three different styles of speech to find acoustic correlates of prominence. We built classifiers, trained the classifiers on human prominence/nonprominence judgments, and then evaluated how well they behaved. The classifiers operate on 452 ms windows centered on syllables, using different acoustic measures. By comparing the performance of classifiers based on different measures, we can learn how prominence is expressed in speech. Contrary to textbooks and common assumption, fundamental frequency (f0) played a minor role in distinguishing prominent syllables from the rest of the utterance. Instead, speakers primarily marked prominence with patterns of loudness and duration. Two other acoustic measures that we examined also played a minor role, comparable to f0. All dialects and speaking styles studied here share a common definition of prominence. The result is robust to differences in labeling practice and the dialect of the labeler.     

Direct magnitude estimation and interval scaling of pleasantness and severity in dysphonic and normal speakers

The purpose of this study was to determine the validity of voice pleasantness and overall voice severity ratings of dysphonic and normal speakers using direct magnitude estimation (DME) and equal-appearing interval (EAI) auditory-perceptual scaling procedures. Twelve naive listeners perceptually evaluated voice pleasantness and severity from connected speech samples produced by 24 adult dysphonic speakers and 6 normal adult speakers. A statistical comparison of the two auditory-perceptual scales yielded a linear relationship representative of a metathetic continuum for voice pleasantness. A statistical relationship that is consistent with a prothetic continuum was revealed for ratings of voice severity. These data provide support for the use of either DME or EAI scales when making auditory-perceptual judgments of pleasantness, but only DME scales when judging overall voice severity for dysphonic speakers. These results suggest further psychophysical study of perceptual dimensions of voice and speech must be undertaken in order to avoid the inappropriate and invalid use of EAI scales used in the auditory-perceptual evaluation of the normal and dysphonic voice.