Vocal tract dimensional development of adolescents: An acoustic reflection study

Objective

The purpose of the study was to investigate the effects of age and gender on adolescents’ vocal tract dimensional development with acoustic reflection technology (ART).

Methods

A total of ninety-five male and female adolescents aged between 10 and 18 divided into three age groups were tested with acoustic reflection technology (ART) and acoustic program to secure their vocal tract dimensional parameters and the vowel formant frequencies.

Results

Significant age and gender effects were found not only in vocal tract length, but also segmental volumetric measurements, as well as the vowel formant frequencies.

Conclusions

The findings of this study have provided insights on the developmental trend of adolescents’ vocal tracts. The study has also offered a preliminary anatomical database of adolescents’ vocal tract dimensional growth for otolaryngologists, clinical anatomists, speech therapists and other health professionals of swallowing, respiration and communicative disorders.     

The effect of radiofrequency volumetric tissue reduction of soft palate on voice

The surgical techniques used for snoring and OSA treatment include partial/complete resection or tissue reduction of the oropharyngeal structures such as uvula, tonsilla palatinas, soft palate, lateral pharyngeal tissues and tongue base. So it is predictable for these techniques to affect the resonating volume of the vocal tract and therefore the speech sounds. The goal of this study was to evaluate whether radiofrequency volumetric tissue reduction (RFVTR) of the soft palate can cause voice changes by altering the formant frequencies and fundamental frequency of vowels. A prospective study of 26 habitual snorers and mild obstructive sleep apnea patients (apnea–hypopnea index, <10 in all cases) were investigated before and 6 weeks after RFVTR. The patients received one Somnoplasty® RFVTR treatment of 1,400 J per treatment session: 700 J into the midline and 350 J on each side of the soft palate with a maximum temperature of 80°C. Acoustic evaluation was made by the Multidimensional Voice Program. The mean fundamental frequency (MF0) and the first three formant frequencies (F1, F2, F3) of four sustained vowels /a/, /e/, /i/ and /o/ were determined. Comparison between preoperative and postoperative acoustic analysis of the MF0 and F1, F2, F3 of sustained vowels revealed no significant change. The findings of the study indicate that RFVTR of the soft palate as a treatment for snoring and mild forms of OSA does not have a significant impact on the mean fundamental frequency and formant frequencies of vowels. These results seem to be important in management of patients with concerns about postoperative vocal quality, such as singers and professional speakers.     

Articulatory changes following treatment of muscle tension dysphonia: preliminary acoustic evidence

PURPOSE: Primary muscle tension dysphonia (MTD), a voice disturbance that occurs in the absence of structural or neurological pathology, may respond to manual circumlaryngeal techniques, which ostensibly alter the posture of the larynx and/or the configuration of the vocal folds without directly targeting supralaryngeal articulatory structures. Although the phonatory benefits of these techniques have been documented previously, this investigation examined whether acoustic evidence exists for articulatory changes accompanying successful management. METHOD: In this retrospective study of a clinical database, pre- and post-treatment speech samples from 111 women with MTD were analyzed for acoustic evidence of supraglottal vocal tract changes associated with voice improvement, which was confirmed by perceptual ratings of dysphonia severity. The slopes of the first and second formants in diphthongs, as well as global measures of speech timing were acquired. Twenty younger females with normal voices were recorded twice, across a similar time-span to the disordered speakers, to allow comparisons in performance. RESULTS: Repeated measures analysis of variance was used to evaluate changes accompanying treatment. Significant time by group interactions for /I/ F2 slope, /eI/ F2 slope, sample duration, and speaking time ratio were observed. As compared to the controls, diphthong second formant transitions increased in slope, and timing measures showed increases in speech continuity for the speakers with MTD. CONCLUSIONS: Collectively, these preliminary findings suggest that individuals with MTD experience changes in both articulatory and phonatory behavior following successful treatment that targets the larynx.     

Isovowel lines for the evaluation of vowel formant structure in speech disorders

This report describes a system of isovowel lines in the F1-F2 and F2-F3 planes and demonstrates how these linear approximations to vowel formant frequencies for a diverse sample of speakers can be used to evaluate the vowel formant structures of individuals with speech disorders. The application to disordered speech is illustrated with data for dysarthric adults, deaf adolescents, and young children with developmental errors of: Formula: (See Text) production.     

An acoustic and perceptual study of final stops produced by profoundly hearing impaired adolescents.

PURPOSE: This study investigated formant frequencies for their role as acoustic and perceptual correlates to the place of articulation of Cantonese final stops produced by profoundly hearing impaired speakers. METHOD: Speakers were 10 Cantonese adolescents (mean age=13;5 [years;months]) who were profoundly hearing impaired (HI). Control speakers were 10 adolescents (mean age=13;5) with normal hearing. Stimuli were Cantonese words that were minimally contrastive in place of final stops (/p, t, k/). Listeners were 10 final-year speech therapy students. The frequencies of F1, F2, and F3 were measured at the middle, 40 ms before the end, and at the end of the vocalic segments. RESULTS: Control speakers distinguished place contrasts through formant frequency differences at the end positions of the vowels. HI speakers produced final stops with missing formant transitions and neutralized vowels preceding final stops. Listeners relied on F2 transition cues for stops produced by control speakers, whereas F1 and F3 transition cues were used for stops produced by HI speakers. CONCLUSIONS: Formant frequencies of final stops produced by HI speakers showed reduced place distinction. When listeners identified the place of final stops produced by HI speakers, they relied on formant frequency cues that were different from those used for stops produced by control speakers.     

Vowel category dependence of the relationship between palate height, tongue height, and oral area.

This article evaluates intertalker variance of oral area, logarithm of the oral area, tongue height, and formant frequencies as a function of vowel category. The data consist of coronal magnetic resonance imaging (MRI) sequences and acoustic recordings of 5 talkers, each producing 11 different vowels. Tongue height (left, right, and midsagittal), palate height, and oral area were measured in 3 coronal sections anterior to the oropharyngeal bend and were subjected to multivariate analysis of variance, variance ratio analysis, and regression analysis. The primary finding of this article is that oral area (between palate and tongue) showed less intertalker variance during production of vowels with an oral place of articulation (palatal and velar vowels) than during production of vowels with a uvular or pharyngeal place of articulation. Although oral area variance is place dependent, percentage variance (log area variance) is not place dependent. Midsagittal tongue height in the molar region was positively correlated with palate height during production of palatal vowels, but not during production of nonpalatal vowels. Taken together, these results suggest that small oral areas are characterized by relatively talker-independent vowel targets and that meeting these talker-independent targets is important enough that each talker adjusts his or her own tongue height to compensate for talker-dependent differences in constriction anatomy. Computer simulation results are presented to demonstrate that these results may be explained by an acoustic control strategy: When talkers with very different anatomical characteristics try to match talker-independent formant targets, the resulting area variances are minimized near the primary vocal tract constriction.     

Effects of long-term tracheostomy on spectral characteristics of vowel production.

This study investigated the effects of long-term tracheostomy on the development of speech. Eight children who underwent tracheotomy during the prelingual period were compared to matched controls on selected spectral parameters of the speech acoustic signal and standard measures of oral-motor, phonologic, and articulatory proficiency. Analysis of formant frequency values revealed significant between-group differences. Children with histories of long-term tracheostomy showed reduced acoustic vowel space, as defined by group formant frequency values. This suggests that these children were limited in their ability to produce extreme vocal tract configurations for vowels (a,i,u) postdecannulation. Oral motor patterns were less mature, and sound substitutions were not only more variable for this group, but also reflected a persistent overlay of maladaptive compensations developed during cannulation.     

Role of vocal tract morphology in speech development: perceptual targets and sensorimotor maps for synthesized French vowels from birth to adulthood.

The development of speech from infancy to adulthood results from the interaction of neurocognitive factors, by which phonological representations and motor control abilities are gradually acquired, and physical factors, involving the complex changes in the morphology of the articulatory system. In this article, an articulatory-to-acoustic model, integrating nonuniform vocal tract growth, is used to describe the effect of morphology in the acoustic and perceptual domains. While simulating mature control abilities of the articulators (freezing neurocognitive factors), the size and shape of the vocal apparatus are varied, to represent typical values of speakers from birth to adulthood. The results show that anatomy does not prevent even the youngest speaker from producing vowels perceived as the 10 French oral vowels /i y u e phi o epsilon oe [symbol: see text] a/. However, the specific configuration of the vocal tract for the newborn seems to favor the production of those vowels perceived as low and front. An examination of the acoustic effects of articulatory variation for different growth stages led to the proposed variable sensorimotor maps for newbornlike, childlike, and adultlike vocal tracts. These maps could be used by transcribers of infant speech, to complete existing systems and to provide some hints about underlying articulatory gestures recruited during growth to reach perceptual vowel targets in French.     

Spectral study of deviant resonance in the speech of women who are deaf.

In a previous radiographic study of 4 deaf women, some aberrant features in vocal tract configuration were identified for vowels produced with excessive pharyngeal resonance. These features included neutralization of tongue position, elevation of the hyoid, and a retraction of the tongue, associated with a deflection of the epiglottis in the lower pharynx. The vowels, produced simultaneously with X-ray exposure, were analyzed spectrographically to study acoustic correlates of the vocal tract deformation. Comparisons of the formants for vowels /i/ /u/ and /a/ produced by the deaf women with mean formant values for these vowels produced by normal-hearing women revealed no consistent pattern of second-formant deviation. Formant structure evaluated on isovowel lines disclosed consistent neutralization of vowels, with F2 values clustering in the 1500-2100 Hz frequency range, which is attributed to the observed restricted horizontal movements of the tongue within the oral and pharyngeal cavities. If such restrictions affect the production of all vowels, a lower F2 might be assumed for the front vowels, which normally have a high F2; a higher F2 frequency would be anticipated for back vowels, which normally have a low F2. The limited sample studied supports this assumption.     

Acoustic and perceptual consequences of articulatory rate change in Parkinson disease.

This study sought to characterize the relationship among voluntary rate modification, vocal tract acoustic output, and perceptual impressions of speech for individuals with idiopathic Parkinson disease (PD). Healthy control speakers were studied for comparison purposes. Four research questions were addressed: (1) How is rate modification evidenced in acoustic measures of segmental and global timing? (2) What is the impact of rate modification on measures of acoustic working space for select vowels and consonants? (3) What is the impact of rate modification on perceptual impressions of severity? (4) Are rate-induced changes in measures of acoustic working space related to perceptual impressions of severity? Speakers read the Farm Passage at habitual, slow, and fast rates. The vowels /i/, /ae/, /u/, and /A/ and the fricatives /s/ and /S/ were of interest. Acoustic measures included articulatory rate, segment durations, vowel formant frequencies, and first moment coefficients. Measures of acoustic working space for vowels and fricatives also were derived. The results indicated that temporal acoustic measures changed in the expected direction across rate conditions, with a tendency toward slightly faster rates for the PD group. In addition, the relative rate change for the Fast and Slow conditions compared to the Habitual condition was similar across groups. Rate did not strongly affect measures of acoustic working space for the PD group as a whole, but there was a tendency for slower rates to be associated with larger measures of acoustic working space. Finally, there was not a strong relationship between perceived severity and measures of acoustic working space across the rate continuum for either group. Rather, the relationship between perceived severity and measures of acoustic working space was such that the PD group exhibited smaller measures of acoustic working space and more severe perceptual estimates than the control speakers, irrespective of rate condition.     

Quantification of vocal tract configuration of older children with Down syndrome: A pilot study

Objective

To quantify the vocal tract (VT) lumen of older children with Down syndrome using acoustic reflection (AR) technology.

Design

Comparative study.

Setting

Vocal tract lab with sound-proof booth.

Participants

Ten children (4 males and 6 females), aged 9-17 years old diagnosed with Down syndrome. Ten typically developing children (4 males and 6 females) matched for age, gender, and race.

Intervention

Each participant's vocal tract measurements were obtained by using an Eccovision Acoustic Pharyngometer.

Main outcome measures

Six vocal tract dimensional parameters (oral length, oral volume, pharyngeal length, pharyngeal volume, total vocal tract length, and total vocal tract volume) from children with Down syndrome and the typically developing children were measured and compared.

Results

Children with Down syndrome exhibited small oral cavities when compared to control group (F(1, 18) = 6.55, p = 0.02). They also demonstrated a smaller vocal tract volumes (F(1, 18) = 2.58, p = 0.13), although the results were not statistically significant at the 0.05 level. Pharyngeal length, pharyngeal volume, and vocal tract length were not significantly different between the two groups.

Conclusion

Children with Down syndrome had smaller oral cavities, and smaller vocal tract volumes. No significant differences were found for pharyngeal length, pharyngeal volume, and vocal tract length between these two groups.     

Perception of oral diadochokinetic performances in elderly adults

Twenty speech-language pathologists judged the adequacy of oral diadochokinetic performances by ten normal young adult speakers, ten normal geriatric speakers, and four dysarthric speakers (foils) for the purpose of investigating age-related changes in speech. Listeners rated each speaker according to 11 perceptual dimensions. Significant differences in ratings were found among the three subject groups for 10 of the 11 perceptual dimensions. The performances of elderly normal adult speakers were rated farther from the "normal" endpoint of a seven-point continuum than those of the young normal adults. The listeners also reported lesser degrees of confidence in their ratings of the geriatrics in comparison with both young adult and dysarthric groups. Perceptual characteristics associated with oral diadochokinetic performance appear to be altered with advanced age. Further analysis of clinicians' judgments suggest support for Ryan and Burk's (1974) proposal that the speech of aged adults may fall at the "mild end of a dysarthric continuum." Results emphasized the need for development of clinical standards of speech normality for the geriatric population.     

An auditory-feedback-based neural network model of speech production that is robust to developmental changes in the size and shape of the articulatory system.

The purpose of this article is to demonstrate that self-produced auditory feedback is sufficient to train a mapping between auditory target space and articulator space under conditions in which the structures of speech production are undergoing considerable developmental restructuring. One challenge for competing theories that propose invariant constriction targets is that it is unclear what teaching signal could specify constriction location and degree so that a mapping between constriction target space and articulator space can be learned. It is predicted that a model trained by auditory feedback will accomplish speech goals, in auditory target space, by continuously learning to use different articulator configurations to adapt to the changing acoustic properties of the vocal tract during development. The Maeda articulatory synthesis part of the DIVA neural network model (Guenther et al., 1998) was modified to reflect the development of the vocal tract by using measurements taken from MR images of children. After training, the model was able to maintain the 11 English vowel targets in auditory planning space, utilizing varying articulator configurations, despite morphological changes that occur during development. The vocal-tract constriction pattern (derived from the vocal-tract area function) as well as the formant values varied during the course of development in correspondence with morphological changes in the structures involved with speech production. Despite changes in the acoustical properties of the vocal tract that occur during the course of development, the model was able to demonstrate motor-equivalent speech production under lip-restriction conditions. The model accomplished this in a self-organizing manner even though there was no prior experience with lip restriction during training.     

Implications of Peripheral Muscular and Anatomical Development for the Acquisition of Lingual Control for Speech Production: A Review

Objectives: Normally developing children learn to produce intelligible speech during rapid, non-uniform growth of their articulators and other vocal tract structures. The purpose of this review is to focus attention on the consequences of peripheral growth and development for the acquisition of lingual control for speech production. This paper (1) reviews physiological underpinnings of tongue shaping and movements that are likely to be changing in young children; (2) estimates, from previously published studies, the net consequences of growth of multiple vocal tract structures on lingual control; (3) integrates our findings with the example of [R] production, and (4) highlights areas where further investigations would be most helpful. Patients and Methods: The authors searched the literature, including the PubMed database, for studies of the development of muscle proteins, muscle fibers, and motor units of the tongue, and of the growth of the tongue, jaw, adenoids, soft and hard palates, oral and pharyngeal cavities, and the vocal tract as a whole. Conclusions: Substantial anatomical and muscular data sets focused on children from 1-4 years of age, and rigorous definitions of the tongue boundaries are needed.     

Effects of tonsillectomy and/or adenoidectomy on vocal function: laryngeal, supralaryngeal and perceptual characteristics

A prospective, non-randomized study evaluated the effects of tonsillectomy and/or adenoidectomy (T +/- A) on acoustic and perceptual aspects of vocal function. Thirty-one children, ranging in age from 4 to 15 years participated and measurements were made prior to and 3 months following surgery. Twenty-three children had T +/- A and eight had adenoidectomy alone. Quantitative acoustic measures included: laryngeal (vocal fundamental frequency, FO) and supralaryngeal characteristics of sustained vowels (F1 and F2 formants, formant bandwidths, two-dimensional measures of vowel space) and temporal properties of consonant-vowel productions (diadochokinetic syllable rates). Perceptual measures were based on samples of continuous speech, using the Buffalo voice profile (BVP) and parental interviews/questionnaires were used to evaluate other aspects of surgery (i.e. subjective speech changes, protracted pain, difficulty swallowing, bleeding, etc.). Based on ANOVA, no significant post-surgical changes were detected for the majority of acoustic speech measures studied (vocal F0, formant bandwidths, measures of vowel space or diadochokinetic rates). However, the F2 formant frequency for vowels /i/ and /a/ increased and F1 decreased for /o/ following surgery. These changes had the largest effect on the structure of vowel /i/, which became more acute and diffuse following surgery. Furthermore, of the majority of perceptual measured studied with the BVP, 92% showed no change postoperatively. However, in the category of resonance, a significant decrease in hyponasality was detected. These results demonstrate that removing soft tissue from the oropharynx has only minimal impact on quantitative or qualitative (perceptual) aspects of vocal function, when measurements are made approximately 15 weeks post surgery.     

Effects of white noise masking and low pass filtering on speech kinematics

The effects of reduced auditory information on spatial and temporal parameters of speech production were investigated using cinefluorographic techniques. While subjects read a series of test words embedded in carrier sentences, they received normal auditory information, auditory information regarding only the first formant of their production, or high level noise to mask all formant information. Kinematic analyses indicated that while there were some changes across conditions, these changes were not consistent either within or across the subjects. Parameters that were affected included mean displacement, vocal tract shape, interarticulator timing, and steady state duration. The results suggest that auditory information plays a role in maintaining dynamic aspects of speech kinematics. That is, while speech can be produced without auditory information, the precise action and coordination that characteristic normal production may be altered.     

Effect of the loss of auditory feedback on segmental parameters of vowels of postlingually deafened speakers

Objective: The most obvious and best documented changes in speech of postlingually deafened speakers are the rate, fundamental frequency, and volume (energy). These changes are due to the lack of auditory feedback. But auditory feedback affects not only the suprasegmental parameters of speech. The aim of this study was to determine the change at the segmental level of speech in terms of vowel formants. Methods: Twenty-three postlingually deafened and 18 normally hearing speakers were recorded reading a German text. The frequencies of the first and second formants and the vowel spaces of selected vowels in word-in-context condition were compared. Results: All first formant frequencies (F1) of the postlingually deafened speakers were significantly different from those of the normally hearing people. The values of F1 were higher for the vowels /e/ (418±61 Hz compared with 359±52 Hz, P=0.006) and /o/ (459±58 compared with 390±45 Hz, P=0.0003) and lower for /a/ (765±115 Hz compared with 851±146 Hz, P=0.038). The second formant frequency (F2) only showed a significant increase for the vowel/e/(2016±347 Hz compared with 2279±250 Hz, P=0.012). The postlingually deafened people were divided into two subgroups according to duration of deafness (shorter/longer than 10 years of deafness). There was no significant difference in formant changes between the two groups. Conclusion: Our report demonstrated an effect of auditory feedback also on segmental features of speech of postlingually deafened people.     

Age-related temporal processing speed deterioration in auditory cortex

A common problem among the elderly is a difficulty in discriminating speech sounds. One factor that may contribute to this is a deterioration in the ability to process dynamic aspects of speech such as formant transitions. For the aging auditory system, this deterioration in temporal processing speed may be manifest as a deficit in encoding time-varying sounds that contain rapidly changing frequencies such as formant transitions. The primary goal of this study was to explore the neural basis of the effects of aging on temporal processing speed. To this end, single units were recorded from the auditory cortex of young and aged rats in response to frequency-modulated (FM) sweeps that changed from trial to trial in both direction and speed. Results showed that the majority of cells recorded from young rats responded most vigorously to fast and medium speeds. By contrast, the majority of units recorded from aged animals responded best to slow speeds. For preferred direction of FM sweep, similar results were observed for both age groups, namely, approximately half of the units exhibited a direction-selective response. The results of the present study demonstrate an age-related decrease in the rate of change of frequency that can be processed by the auditory cortex.     

Acoustic-perceptual correlates of voice quality in elderly men and women

Common perceptual characteristics of the elderly voice include hoarseness, breathiness, instability, and a change in the pitch of the voice. Although research is available concerning changes in the elderly voice, little research has been completed to examine the relationship between the perception of voice quality and acoustic measures. The purpose of this study was to examine the relationship between perceived breathiness and hoarseness and selected acoustic variables. The results of the study revealed significant age-related differences in fundamental frequency standard deviation, amplitude perturbation quotient, and noise-to-harmonic ratio. No significant difference in perceived hoarseness was found between the young and elderly speakers. However, the young women were perceived as significantly more breathy than the elderly women. Moderate correlations were found between the perceptions of hoarseness and breathiness and the acoustic measures. These findings are discussed relative to age-related laryngeal changes that may contribute to the perception of aging. LEARNING OUTCOMES: (1) To understand the perceptual attributes of the aging voice in men and women. (2) To understand the relation between the perception of voice quality and acoustic measures of voice production in the aging voice.