The external frame function in the control of pitch, register, and singing mode: radiographic observations of a female singer

Effects of Age and Parkinson's Disease on the Relationship between Vocal Fold Abductory Kinematics and Relative Fundamental Frequency

PURPOSE

This study reports on two experiments to examine vocal fold abduction and its relationship with relative fundamental frequency (RFF), considering two attributes that have been shown to elicit group differences in RFF: age (Experiment 1) and Parkinson's disease (PD; Experiment 2).

METHODS

For both experiments, simultaneous acoustic and nasendoscopic recordings were collected as participants produced the utterance, /ifi/. RFF values were computed from the acoustic signal, whereas abduction duration and glottic angle at voicing offset were identified from the laryngoscopic images. In Experiment 1, 50 speakers with typical voices (18-83 years) were analyzed to examine (1A) the effects of speaker age on individual outcome measures (RFF, abduction duration, glottic angle) via Pearson's correlation coefficients, and (1B) the effects of abductory measures and age on RFF via an analysis of covariance. In Experiment 2, 20 speakers with PD and 20 matched controls were analyzed to examine (2A) the effects of group (with/without PD) on outcome measures via an analysis of variance, and (2B) the relationship of RFF with abduction duration, glottic angle, and age when considering group via an analysis of covariance.

RESULTS

Age demonstrated a significant, negative relationship with glottic angle (1A) but was not a significant factor when examining the relationship of vocal fold abduction and RFF (1B). Speaker group (with/without PD) demonstrated a significant effect on measures of RFF and abduction duration (2A) but was not a significant factor when examining the relationship of vocal fold abduction and RFF (2B).

CONCLUSIONS

RFF is sensitive to changes in vocal fold abductory patterns during devoicing, irrespective of speaker age or PD status.

Three Professional Singers' Vocal Tract Dimensions in Operatic Singing, Kulning, and Edge-A Multiple Case Study Examining Loud Singing

OBJECTIVE

A comprehensive understanding of how vocal tract dimensions vary among different types of loud voice productions has not yet been fully formed. This study aims to expand the existing knowledge on the topic.

METHODS

Three trained professional singers together practiced the vocal techniques underlying Opera and Kulning singing styles for one hour and, afterwards, phonated using these techniques on vowel [iː] at pitch C5 (523 Hz), while their vocal tracts were scanned via MRI. One of the participants also produced the samples in the Edge vocal mode using [ɛː]. Several dimensional vocal tract measurements were calculated from the MRIs. Spectral analysis was conducted on the filtered audio recorded during the MRI.

RESULTS

The Operatic technique demonstrated a lower larynx, a larger tongue-palate distance, and larger epilaryngeal and pharyngeal tube diameters compared to Kulning. Edge showed the highest laryngeal position, narrowest pharynx and epilarynx tubes, and the least forward-tilted larynx out of the styles studied. The spectra of Opera and Kulning showed a dominant first harmonic, while in Edge, the second harmonic was the strongest.

CONCLUSIONS

The results shed light on the magnitude of vocal tract changes necessary for genre-typical vocal projection. This information can be pedagogically helpful.

CPPS and Voice-Source Parameters: Objective Analysis of the Singing Voice

INTRODUCTION

In recent years cepstral analysis and specific cepstrum-based measures such as smoothed cepstral peak prominence (CPPS) has become increasingly researched and utilized in attempts to determine the extent of overall dysphonia in voice signals. Yet, few studies have extensively examined how specific voice-source parameters affect CPPS values.

OBJECTIVE

Using a range of synthesized tones, this exploratory study sought to systematically analyze the effect of fundamental frequency (fo), vibrato extent, source-spectrum tilt, and the amplitude of the voice-source fundamental on CPPS values.

MATERIALS AND METHODS

A series of scales were synthesised using the freeware Madde. Fundamental frequency, vibrato extent, source-spectrum tilt, and the amplitude of the voice-source fundamental were systematically and independently varied. The tones were analysed in PRAAT, and statistical analyses were conducted in SPSS.

RESULTS

CPPS was significantly affected by both fo and source-spectrum tilt, independently. A nonlinear association was seen between vibrato extent and CPPS, where CPPS values increased from 0 to 0.6 semitones (ST), then rapidly decreased approaching 1.0 ST. No relationship was seen between the amplitude of the voice-source fundamental and CPPS.

CONCLUSION

The large effect of fo should be taken into account when analyzing the voice, particularly in singing-voice research, when comparing pre and posttreatment data, and when comparing inter-subject CPPS data.

Voice Outcomes Following Head-Lift Exercises in Head and Neck Cancer: A Randomized Controlled Study

OBJECTIVES

This prospective randomized study aimed to investigate whether patients with dysphagia after treatment for head and neck cancer improve their vocal function from doing head lift exercises (Shaker's exercise).

METHODS

Patients were randomized into an intervention group (n = 24) or a control group (n = 26). Patients in the intervention group performed the head lift exercise three times a day for 8 weeks. At baseline and at follow-up after 8 weeks, participants' voices were evaluated perceptually with the Grade-Roughness-Breathiness-Asthenia-Strain (GRBAS) scale. Vocal fry (VF) was also perceptually evaluated and patients filled in the Voice Handicap Index (VHI).

RESULTS

Patients in the intervention group were perceptually evaluated as having less roughness and vocal fry in their voices at follow-up compared to the control group. There were no statistically significant changes between baseline and follow-up neither in the intervention nor the control group regarding GRBAS, VF, or VHI. Neither were there any statistically significant differences within the groups when results on the perceptual evaluations at baseline and follow-up were compared.

CONCLUSIONS

The voices of the participants in the intervention group were slightly better than the voices of the participants in the control group with less roughness and VF at follow-up. However, no improvement in the VHI or the remaining GRBAS variables was found. Therefore, this study can only give cautious support to the head lift exercise as a method for improving the voice of patients with dysphagia after treatment for head and neck cancer.

Analysis of vibratory mode changes in symmetric and asymmetric activation of the canine larynx

Investigations of neuromuscular control of voice production have primarily focused on the roles of muscle activation levels, posture, and stiffness at phonation onset. However, little work has been done investigating the stability of the phonation process in regards to spontaneous changes in vibratory mode of vocal fold oscillation as a function of neuromuscular activation. We evaluated 320 phonatory conditions representing combinations of superior and recurrent laryngeal nerve (SLN and RLN) activations in an in vivo canine model of phonation. At each combination of neuromuscular input, airflow was increased linearly to reach phonation onset and beyond from 300 to 1400 mL/s. High-speed video and acoustic data were recorded during phonation, and spectrograms and glottal-area-based parameters were calculated. Vibratory mode changes were detected based on sudden increases or drops of local fundamental frequency. Mode changes occurred only when SLNs were concurrently stimulated and were more frequent for higher, less asymmetric RLN stimulation. A slight increase in amplitude and cycle length perturbation usually preceded the changes in the vibratory mode. However, no inherent differences between signals with mode changes and signals without were found.

Finite element modeling of the effects of velopharyngeal opening on vocal tract reactance in female voice

Classical singers use nasal consonants as "resonance exercises," and experimental results have shown that singers may use some velopharyngeal opening (VPO), most often in [a:] and more seldom in [i:] or [u:]. In particular, male singers have been found to increase VPO as pitch rises toward register change frequencies (passaggi). Laryngoscopic findings have shown that some VPO stabilizes vocal fold vibration; the effect is related to positive reactance. This study investigates the effects of VPO on vocal tract (VT) reactance over the range of fundamental frequencies (f₀) used in singing using a computerized tomography-based finite element model of the VT and nose of a female. According to the results, by raising the lowest VT resonances, the VPO increased the VT reactance in the frequency ranges 207-359 Hz for [i:], 265-411 Hz for [u:], and 500-611 Hz for [a:], depending on the VPO size (full or half VPO). These frequency ranges are close to the first and second passaggio of a female singer. The change may have an especially practical stabilizing effect for [a:], which is otherwise characterized by very large changes in VT reactance and negative reactance at the second passaggio.

Contribution of Weight and Volume of the Extirpated Thyroid Gland on Voice Alterations After Total Thyroidectomy in Patients With Papillary Carcinoma of the Thyroid

PURPOSE

Voice change after thyroid surgery is common despite preservation of laryngeal nerves. In this study, we sought to find if the change in voice after total thyroidectomy is related to the weight and volume of the removed thyroid gland.

METHODS

This is a prospective cohort study of 50 patients of papillary carcinoma of the thyroid treated with total thyroidectomy from December 2016 through May 2018. Both objective and subjective voice parameters were analyzed preoperatively and at 1 and 3 months following surgery.

RESULTS

A cohort of 29 patients, with a median age of 31 years (18-64 years), comprising 22 women were eligible for final analysis. Speaking fundamental frequency showed a mean change of 17.21 Hz (SD 34.49) while the mean intensity change was 5.54 dB (SD 18.21). The mean weight and volume of thyroid gland was 18.99 g (SD 8.93) and 15.67 ml (SD 8.70), respectively. On multivariate analysis, both weight and volume affected the range of frequency (P = 0.002 and 0.035, respectively) and range of intensity (P = 0.014 and 0.008, respectively).

CONCLUSION

Larger thyroid tumors are more likely to be associated with transient change in voice quality following their surgical removal despite physical preservation of external and recurrent laryngeal nerves, which may persist up to 3 months. This study affirms that perturbations in voice after thyroidectomy can still exist in spite of clinical demonstration of integrity of neuromuscular function.

Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

Effect of wound massage on neck discomfort and voice changes after thyroidectomy

BACKGROUND

Neck discomfort and voice change are common complications after thyroidectomy. These symptoms might be due to damaged laryngeal nerves, intrinsic structures, or extralaryngeal muscles. They can also occur without injury to any structure as with wound adhesion after thyroidectomy. The objective of this study was to determine causes of neck discomfort and voice change after thyroidectomy and to evaluate the effect of wound massage on symptom relief.

METHODS

Forty-five female patients who underwent total thyroidectomy were included (21 in the experimental group and 24 in the control group). Wound massage was used as an intervention to release surgical adhesion. After wound massage education, participants in the experimental group received wound massage from 4 to 12 weeks after thyroidectomy. Analysis was performed for both groups.

RESULTS

No laryngeal pathology was found after thyroidectomy. The experimental group had significantly better recovery from surgical adhesion and subjective visual analog scale, voice impairment score, and swallowing impairment score (all P < .01) compared with the control group. Voice analysis results associated with laryngeal movement (speaking fundamental frequency, voice range profile maximum, voice range profile range) also indicated significant recovery (P < .01) in the experimental group. These results indicate that local adhesion after thyroidectomy might affect general movement of the larynx and that wound massage could help patients recover normal general movement of the larynx.

CONCLUSION

Neck discomfort and voice change after thyroidectomy are related to local wound adhesion, possibly associated with impairment of laryngeal vertical movement. Release of wound adhesion could help patients recover from neck discomfort and voice changes after thyroidectomy.

Changes in Oral Vowel Sounds and Hyoid Bone Movement After Thyroidectomy

OBJECTIVES

Voice and speech alterations after total thyroidectomy may be associated with other extralaryngeal factors, such as neck muscle dysfunction and neck scar contracture. We evaluated the acoustic characteristics of oral vowel sounds and changes in hyoid bone movement before and after thyroidectomy.

METHODS

Twenty-nine female patients undergoing total thyroidectomy were included. Fundamental frequencies (Fo), formants and vowel space areas were evaluated before surgery and 7 days and 3 months after surgery to acoustically analyze the oral vowel sounds. Videofluoroscopic images were taken at the same times to evaluate hyoid bone movement.

RESULTS

The Fo levels of seven vowels decreased significantly after surgery. The vowel formant changes the F1 of vowel /[e]/ decreased significantly from baseline at 3 months postoperatively, and the F3 of vowel /[i]/ decreased significantly from baseline 7 days postoperatively. The change in the vowel space area was not observed. The Y coordinate of the vowels /[i]/ and /[e]/ decreased significantly from baseline 7 days postoperatively due to changes in hyoid movement.

CONCLUSION

The damage to the neck muscles after thyroidectomy changes in Fo, formant and hyoid bone position. These quantitative results could be used as basic data for voice management in patients who undergo thyroidectomy.

Laryngeal evidence for the first and second passaggio in professionally trained sopranos

Introduction

Due to a lack of empirical data, the current understanding of the laryngeal mechanics in the passaggio regions (i.e., the fundamental frequency ranges where vocal registration events usually occur) of the female singing voice is still limited.

Material and methods

In this study the first and second passaggio regions of 10 professionally trained female classical soprano singers were analyzed. The sopranos performed pitch glides from A3 (ƒ_o = 220 Hz) to A4 (ƒ_o = 440 Hz) and from A4 (ƒ_o = 440 Hz) to A5 (ƒ_o = 880 Hz) on the vowel [iː]. Vocal fold vibration was assessed with trans-nasal high speed videoendoscopy at 20,000 fps, complemented by simultaneous electroglottographic (EGG) and acoustic recordings. Register breaks were perceptually rated by 12 voice experts. Voice stability was documented with the EGG-based sample entropy. Glottal opening and closing patterns during the passaggi were analyzed, supplemented with open quotient data extracted from the glottal area waveform.

Results

In both the first and the second passaggio, variations of vocal fold vibration patterns were found. Four distinct patterns emerged: smooth transitions with either increasing or decreasing durations of glottal closure, abrupt register transitions, and intermediate loss of vocal fold contact. Audible register transitions (in both the first and second passaggi) generally coincided with higher sample entropy values and higher open quotient variance through the respective passaggi.

Conclusions

Noteworthy vocal fold oscillatory registration events occur in both the first and the second passaggio even in professional sopranos. The respective transitions are hypothesized to be caused by either (a) a change of laryngeal biomechanical properties; or by (b) vocal tract resonance effects, constituting level 2 source-filter interactions.

A Review of Singing Voice Subsystem Interactions-Toward an Extended Physiological Model of "Support"

During phonation, the respiratory, the phonatory, and the resonatory parts of the voice organ can interact, where physiological action in one subsystem elicits a direct effect in another. Here, three major subsystems of these synergies are reviewed, creating a model of voice subsystem interactions: (1) Vocal tract adjustments can influence the behavior of the voice source via nonlinear source-tract interactions; (2) The type and degree of vocal fold adduction controls the expiratory airflow rate; and (3) The tracheal pull caused by the respiratory system affects the vertical larynx position and thus the vocal tract resonances. The relevance of the presented model is discussed, suggesting, among others, that functional voice building work concerned with a particular voice subsystem may evoke side effects or benefits on other subsystems, even when having a clearly defined and isolated physiological target. Finally, four seemingly incongruous historic definitions of the concept of singing voice "support" are evaluated, showing how each of these pertain to different voice subsystems at various levels of detail. It is argued that presumed discrepancies between these definitions can be resolved by putting them into the wider context of the subsystem interaction model presented here, thus offering a framework for reviewing and potentially refining some current and historical pedagogical approaches.

Vocal and Neural Responses to Unexpected Changes in Voice Pitch Auditory Feedback During Register Transitions

OBJECTIVE/HYPOTHESIS

It is known that singers are able to control their voice to maintain a relatively constant vocal quality while transitioning between vocal registers; however, the neural mechanisms underlying this effect are not understood. It was hypothesized that greater attention to the acoustical feedback of the voice and increased control of the vocal musculature during register transitions compared with singing within a register would be represented as neurological differences in event-related potentials.

STUDY DESIGN/METHODS

Nine singers sang musical notes at the high end of the modal register (the boundary between the modal and the head/falsetto registers) and at the low end (the boundary between the modal and the fry/pulse registers). While singing, the pitch of the voice auditory feedback was unexpectedly shifted either into the adjacent register ("toward" the register boundary) or within the modal register ("away from" the boundary). Singers were instructed to maintain a constant pitch and ignore any changes to their voice feedback.

RESULTS

Vocal response latencies and magnitude of the accompanying N1 and P2 event-related potentials were greatest at the lower (modal-to-fry) boundary when the pitch shift carried the subjects' voices into the fry register as opposed to remaining within the modal register.

CONCLUSIONS

These findings suggest that when a singer lowers the pitch of his or her voice such that it enters the fry register from the modal register, there is increased sensory-motor control of the voice, reflected as increased magnitude of the neural potentials to help minimize qualitative changes in the voice.

Effortful pitch glide: a potential new exercise evaluated by dynamic MRI

PURPOSE

The purpose of this study was to compare the biomechanics of the effortful pitch glide (EPG) with swallowing using dynamic MRI. The EPG is a combination of a pitch glide and a pharyngeal squeeze maneuver for targeting laryngeal and pharyngeal muscles. The authors hypothesized that the EPG would elicit significantly greater structural excursions of anterior hyoid, superior hyoid, hyolaryngeal approximation, laryngeal elevation, and lateral pharyngeal wall medialization compared with swallowing.

METHOD

Eleven healthy, young subjects with a mean age of 25 were recruited. The EPG was first taught and verified via laryngoscopy. Then 2-planar (coronal and sagittal) dynamic MRI acquisitions captured 10 repeated swallows and 3 EPGs. Kinematic analyses of minimum and maximum excursion of anatomical landmarks were calculated.

RESULTS

Results showed a nonsignificant difference between the 2 tasks for range of excursion with all measured biomechanics except for superior hyoid, where the swallow showed significantly greater excursion. This indicated that swallowing and EPG biomechanics were comparable, lending support for the potential use of the EPG as another nonswallowing exercise.

CONCLUSION

Findings suggest EPG may be an effective exercise to target several important swallowing muscles, especially the long pharyngeal muscles that elevate the larynx and shorten the pharynx in swallowing.

Real-time ultrasonographic assessment of true vocal fold length in professional singers

PURPOSE

To assess changing true vocal fold (TVF) length with ultrasonography.

MATERIALS

Thirty-five professional singers (12 tenors and 23 sopranos) were included in this study. Each subject had a documented TVF length with laryngeal ultrasonography (SonoAce X6 scanner; Samsung Medison, Seoul, Korea) during respiration, phonation, and singing.

RESULTS

The average TVF lengths could be measured in each situation with real-time laryngeal ultrasonography. The mean (standard deviation [SD]) of TVF length was 1.71 cm (0.29) at inspiration, 1.56 cm (0.26) at expiration, 1.70 cm (0.21) at comfort phonation, 2.00 cm (0.22) at the highest tone, and 1.47 cm (0.19) at the lowest tone in tenors. In sopranos, the mean (SD) was 1.35 cm (0.12) at inspiration, 1.17 cm (0.12) at expiration, 1.42 cm (0.12) at comfort phonation, 1.65 cm (0.12) at the highest tone, and 1.14 cm (0.15) at the lowest tone. All variables had significant differences between both sexes (P<0.01). The lengths showed statistically significant differences in each phase (P<0.01). The differences in length between each phase were evaluated as well. When analyzed in each sex, all variables were statistically different except few of them. In both sexes, the highest tone and comfort phonation showed no difference (P=0.081 in tenors and P=0.289 in sopranos). The inspiratory phase and comfort phonation had significant difference only in sopranos (P<0.01) in contrast to tenors (P=0.905).

CONCLUSION

Ultrasonographic measurement of TVF could be used to assess physiological variation of TVF. To reach a high-pitched voice, the professional singers used similar range of TVF length at comfort phonation. TVF length was affected more by inspiration in tenors. In sopranos, TVF at comfort phonation was significantly lengthened than in tenors.

Stereotypic laryngeal and respiratory motor patterns generate different call types in rat ultrasound vocalization

Rodents produce highly variable ultrasound whistles as communication signals unlike many other mammals, who employ flow-induced vocal fold oscillations to produce sound. The role of larynx muscles in controlling sound features across different call types in ultrasound vocalization (USV) was investigated using laryngeal muscle electromyographic (EMG) activity, subglottal pressure measurements and vocal sound output in awake and spontaneously behaving Sprague-Dawley rats. Results support the hypothesis that glottal shape determines fundamental frequency. EMG activities of thyroarytenoid and cricothyroid muscles were aligned with call duration. EMG intensity increased with fundamental frequency. Phasic activities of both muscles were aligned with fast changing fundamental frequency contours, for example in trills. Activities of the sternothyroid and sternohyoid muscles, two muscles involved in vocal production in other mammals, are not critical for the production of rat USV. To test how stereotypic laryngeal and respiratory activity are across call types and individuals, sets of ten EMG and subglottal pressure parameters were measured in six different call types from six rats. Using discriminant function analysis, on average 80% of parameter sets were correctly assigned to their respective call type. This was significantly higher than the chance level. Since fundamental frequency features of USV are tightly associated with stereotypic activity of intrinsic laryngeal muscles and muscles contributing to build-up of subglottal pressure, USV provide insight into the neurophysiological control of peripheral vocal motor patterns.

Analysis of male singers laryngeal vertical displacement during the first passaggio and its implications on the vocal folds vibratory pattern

OBJECTIVES

The first voice passaggio in classical western singing is characterized by changes in the vocal tract resonance and configuration around the middle C region (261.62 Hz). Many singers agree that something occurs at the level of the vocal folds to aid the demand for higher frequencies. However, although many singers explore this transitional mechanism, little is known about its precise physiology and association with the vertical displacement of the larynx. The objective of this study is to describe the implications of the vocal tract readjustment and the vocal folds vibration during the passaggio.

METHODS

The study consisted of 11 well-experienced singers performing an ascending scale up to a few notes above middle C while maintaining a consistent vocal tract configuration and finally sustaining the very last note, hence violating the normal passaggio. Subsequently, they reproduced the last sustained note with their traditional configuration of the larynx--western opera singing style. The data were collected with an electroglottography device. A repeated-measures analysis of variance (ANOVA) was applied to analyze the vocal tract length changes, vocal fold contact area (VFCA), and closure quotient before and after the first passaggio. A paired sample t test was implemented to analyze the formants transition.

RESULTS

The results show a significant difference of scores for the formants transition, VFCA, and vocal tract length suggesting that the larynx lowers after the passaggio. This displacement of the larynx is associated with changes on the vocal folds vibratory pattern conjecturably altering from essentially isotonic contraction of the thyroarytenoid muscle to isometric contraction.

Glottal behavior in the high soprano range and the transition to the whistle register

The high soprano range was investigated by acoustic and electroglottographic measurements of 12 sopranos and high-speed endoscopy of one of these. A single laryngeal transition was observed on glissandi above the primo passaggio. It supports the existence of two distinct laryngeal mechanisms in the high soprano range: M2 and M3, underlying head and whistle registers. The laryngeal transition occurred gradually over several tones within the interval D#5-D6. It occurred over a wider range and was completed at a higher pitch for trained than untrained sopranos. The upper limit of the laryngeal transition during glissandi was accompanied by pitch jumps or instabilities, but, for most singers, it did not coincide with the upper limit of R1:f(0) tuning (i.e., tuning the first resonance to the fundamental frequency). However, pitch jumps could also be associated with changes in resonance tuning. Four singers demonstrated an overlap range over which they could sing with a full head or fluty resonant quality. Glottal behaviors underlying these two qualities were similar to the M2 and M3 mechanisms respectively. Pitch jumps and discontinuous glottal and spectral changes characteristic of a M2-M3 laryngeal transition were observed on decrescendi produced within this overlap range.

The effects of humming and pitch on craniofacial and craniocervical morphology measured using MRI

OBJECTIVES/HYPOTHESIS

Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using magnetic resonance imaging, we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.

STUDY DESIGN/METHOD

In this cross-sectional study, 10 healthy volunteers (five men, five women, aged 20-47 years, median 25 years), including singers (6 months to 10 years tuition, median 2 years) and non-singers, were assessed to establish the lowest and highest notes they could comfortably sustain while humming over 20 seconds. With head position stable, midsagittal images were acquired while volunteers hummed these predetermined low and high notes. Twenty-two craniocervical, angular, and linear dimensions defined on these images were compared using one-way repeated-measures analysis of variance. Correlations between variables were sought using Pearson correlation coefficient.

RESULTS

We found significant differences between low- and high-note conditions in six of 22 measures and widespread pitch-related correlations between variables (r≥0.63, P<0.05). Compared with low-note humming, high-note humming was accompanied by increased craniocervical angles opt/nsl and cvt/nsl (P=0.008 and 0.002, respectively); widening of the C3-menton distance (P=0.003), a rise of the larynx and hyoid in relation to the cranial base (P=0.012 and <0.001, respectively), and an increased sternum-hyoid distance (P<0.001).

CONCLUSION

Voice production is accompanied by pitch-related adjustments that are currently being masked by, or mistakenly attributed to, articulatory or postural input, identification of which could improve understanding of mechanisms underlying speech and song.

Defining ‘open throat’ through content analysis of experts’ pedagogical practices

'Open throat' is a term regularly used in the singing studio, but agreement across pedagogues as to its definition and function has not yet been assessed. Fifteen expert singing pedagogues participated in a qualitative study involving a semi-structured interview to explore current thinking regarding terminology, pedagogy, sound quality and the perceived physiology to achieve open throat, as used in the singing studio. Most teachers included the use of the technique as a fundamental in singing training, and were positive about the sound quality it achieved, especially in classical singing. The purpose of the technique was described as a way of maximizing pharyngeal space and/or achieving abduction of the ventricular folds.

The demands of professional opera singing on cranio-cervical posture

Difficulty with singing is a rare but important complication following cervical spine surgery but there is little objective information regarding the cervical and head postural changes taking place during singing. The aim of this study was to identify postural changes in the cranio-cervical region associated with the demands of voice production in professional opera singing. The two Roentgen-cephalograms, one of which are taken whilst performing a specified singing task were taken from 18 professional opera students, 12 females (mean age 20.86 +/- 3.07 years) and six males (18.66 +/- 1.36 years). A paired t test compared mean cranio-cervical postural and pharyngeal/hyoid variables between the two registrations (P = 0.05). The association between the cranio-cervical postural variables and the pharyngeal/hyoid region in each registration position was examined using Spearman's rank correlation coefficient. In singing, the position of the atlas with respect to the true vertical (P < 0.001), the axis (P < 0.001) and the C4 vertebra both with respect to the horizontal (P < 0.001), and the axis with respect to the cranium (P < 0.001), were all significantly different to those at rest. Of the cranio-cervical postural variables in the singing registration, the angles measuring positional change of the atlas and C4 relative to the true horizontal were shown be significantly related to an increased pharyngeal airway space at the C3 level (P < 0.01). An appreciation of the requirement for the cervical spine to undergo postural change during professional opera singing has relevance to the potential impact on voice quality in professional opera singers should they undergo cervical spine surgery.

Does an exercise aimed at improving swallow function have an effect on vocal function in the healthy elderly?

Age-related sarcopenia or muscle wasting contributes to changes in the ability to perform activities of daily living, changes in deglutition, and changes in vocal function. The Shaker Exercise, an isometric and isokinetic exercise, has been shown to strengthen suprahyoid muscles and increase deglutitive anteroposterior (AP) upper esophageal sphincter (UES) opening diameter. The aim of this study was to determine if this exercise has an effect on the age-related changes in vocal function and deglutition in healthy older adults. Eleven females and 10 males, aged 65-78 years (mean = 70 +/- 4 years) and with a negative history for dysphagia and voice disorders, participated by exercising three times per day for 6 weeks. Five age-matched controls did not perform the exercise. Acoustic analysis of voice and biomechanical analysis of deglutition were performed before and after 6 weeks of exercise. Controls participated in voice analysis only. Dysphonia Severity Index (DSI), a multivariate voice index, was used to compare voice production initially and after 6 weeks. Deglutitive biomechanical measures increased and DSI scores improved in 10 of 21 participants following 6 weeks of the exercise. DSI for controls did not change over the 6-week period. Ten of 21 exercise participants experienced improved deglutitive biomechanics and DSI scores. Accuracy of exercise performance, compliance, and/or disclosed alterations in health status may contribute to the lack of deglutitive and DSI change in the participants who did not experience change in function. A large randomized control study, including periodic monitoring of health status, exercise performance accuracy, and compliance, is warranted to evaluate the affect of this exercise on deglutition as well as voice. The Shaker Exercise could be recommended as a preventative measure to diminish the effect of sarcopenia on the muscles used in deglutition and voice and alter the progression of the characteristic senescent voice and swallow changes.

Effects of topical anesthetic and flexible fiberoptic laryngoscopy on professional sopranos

This study examined the acoustic and perceptual effects of topical anesthetic and flexible fiberoptic laryngoscopy (FFL) against a control condition on the singing voices of ten professional sopranos. Recordings of a section of an aria, various scales, and a messa di voce exercise were obtained in the three experimental conditions. Acoustic analyses of the same aria section recorded during the three conditions were similar with respect to the distribution of energy across the spectrum (LTAS) and vibrato rate and extent. The ability of the participants to achieve their highest and lowest notes or to complete the messa di voce was also not affected by the anesthetic or FFL. Perceptual ratings of a variety of parameters by experienced singing teachers also revealed little difference across conditions with only "appropriate velopharyngeal closure" found to differ in one comparison. These results indicate that highly experienced operatic sopranos are either not affected by or appear to have the ability to compensate for the presence of anesthetic and the FFL. The most likely explanation is that this group of singers relied on a solid vocal technique. Results will need to be replicated on less accomplished singers before concluding that this medical procedure does not affect the operatic singing voice.

Clinical feasibility of the new technique of functional 3D laryngeal CT

CONCLUSIONS

Functional 3D laryngeal CT (F3DLxCT) is an informative tool for visualizing the active changes in length, tension and mass of the vocal folds for pitch control. Furthermore, volume defects and level differences of paralyzed vocal folds are easily detectable with this new technique.

OBJECTIVE

To evaluate the clinical feasibility of F3DLxCT images, which can provide clear coronal images of the vocal fold in each anteroposterior direction during phonation and in the resting state.

MATERIAL AND METHODS

FLxCT images were reconstructed to three dimensions to visualize laryngeal motion. FLxCT was performed in four normal controls and in four patients with unilateral vocal fold paralysis in the resting state and during phonation with three vowel sounds of different pitch. 3D images were reconstructed with segmentation and a surface-rendering algorithm on a PC, using the DICOM file of axial images.

RESULTS

The dynamic vocal fold 3D image during phonation could visualize that the thickness and volume were decreased in relatively to the pitch increase. Typical subglottic shoulder-like image formation and ventricular widening were noted with the high-pitch tone.

Pitch-synchronous changes in the anterior cricothyroid space during singing

Pitch-synchronous changes in the anterior cricothyroid (CT) space were registered with ultrasonography (USG) for ten healthy subjects (5 males, 5 females) during the production of musical fifths throughout the whole voice range. One of the males and one of the females were trained amateur singers, the other subjects were choir singers. The average decrease in CT space per a musical fifth was 1.3-2.4 mm for the males and 1.0-1.8 mm for the females; the average decrease was smaller in the middle of the pitch range for both genders. The results suggest that (1) USG can be used for detection of pitch-synchronous changes in the CT space; (2) these changes are dependent on pitch range; and (3) more trained singers tend to have somewhat smaller changes than less trained subjects at certain frequencies. The results seem to indicate that F0 control mechanism varies according to pitch range and register, and possibly according to individual structure and vocal technique related differences.

Effects of inhalatory abdominal wall movement on vertical laryngeal position during phonation

The configuration of the body resulting from inhalatory behavior is sometimes considered a factor of relevance to voice production in singing and speaking pedagogy and in clinical voice therapy. The present investigation compares two different inhalatory behaviors: (1) with a "paradoxical" inward movement of the abdominal wall, and (2) with an expansion of the abdominal wall, both with regard to the effect on vertical laryngeal position during the subsequent phonation. Seventeen male and 17 female healthy, vocally untrained subjects participated. No instructions were given regarding movements of the rib cage. Inhaled air volume as measured by respiratory inductive plethysmography, was controlled to reach 70% inspiratory capacity. Vertical laryngeal position was recorded by two-channel electroglottography during the subsequent vowel production. A significant effect was found; the abdomen-out condition was associated with a higher laryngeal position than the abdomen-in condition. This result apparently contradicted a hypothesis that an expansion of the abdominal wall would allow the diaphragm to descend deeper in the torso, thereby increasing the tracheal pull, which would result in a lower laryngeal position. In a post-hoc experiment including 6 of the subjects, body posture was studied by digital video recordings, revealing that the two inhalatory modes were clearly associated with postural changes affecting laryngeal position. The "paradoxical" inward movement of the abdominal wall was associated with a recession of the chin toward the neck, such that the larynx appeared in a lower position in the neck, for reasons of a postural change. The results suggest that the laryngeal position can be affected by the inhalatory behavior if no attention is paid to posture, implying that instructions from clinicians and pedagogues regarding breathing behavior must be carefully formulated and adjusted in order to ensure that the intended goals are reached.