Marco Guzman

Vocal Tract and Glottal Function During and After Vocal Exercising With Resonance Tube and Straw

OBJECTIVE The present study aimed to investigate the vocal tract and glottal function during and after phonation into a tube and a stirring straw. METHODS A male classically trained singer was assessed. Computerized tomography (CT) was performed when the subject produced [a:] at comfortable speaking pitch, phonated into the resonance tube and when repeating [a:] after the exercise. Similar procedure was performed with a narrow straw after 15 minutes silence. Anatomic distances and area measures were obtained from CT midsagittal and transversal images. Acoustic, perceptual, electroglottographic (EGG), and subglottic pressure measures were also obtained. RESULTS During and after phonation into the tube or straw, the velum closed the nasal passage better, the larynx position lowered, and hypopharynx area widened. Moreover, the ratio between the inlet of the lower pharynx and the outlet of the epilaryngeal tube became larger during and after tube/straw phonation. Acoustic results revealed a stronger spectral prominence in the singer/speakers formant cluster region after exercising. Listening test demonstrated better voice quality after straw/tube than before. Contact quotient derived from EGG decreased during both tube and straw and remained lower after exercising. Subglottic pressure increased during straw and remained somewhat higher after it. CONCLUSION CT and acoustic results indicated that vocal exercises with increased vocal tract impedance lead to increased vocal efficiency and economy. One of the major changes was the more prominent singers/speakers formant cluster. Vocal tract and glottal modifications were more prominent during and after straw exercising compared with tube phonation.

Changes in glottal contact quotient during resonance tube phonation and phonation with vibrato.

Phonating into narrow hard-walled tubes of varying diameters and length as an extension of the vocal tract is considered a semioccluded vocal tract exercise. Semioccluded vocal tract postures have been postulated to have a therapeutic effect during the treatment of the dysphonic patient. They appear to affect at least two components of the voice source (1) glottal flow pulse and (2) vibrational characteristics of the vocal folds. Vibrato also has been described as a possible therapeutic tool and may decrease phonatory hyperfunction. The aim of this study was to determine the influence of resonance tubes and phonation with vibrato on the closed quotient. Thirty-six adult classical singers were recruited for this study. Subjects were asked to produce four phonatory tasks at comfortable pitch and loudness: sustained vowel [a:] without vibrato, sustained vowel [a:] with vibrato, sustained phonation into a straw without vibrato, and sustained phonation into a straw with vibrato. Computer analysis of the contact quotient (CQ) was performed for each type of phonation in every participant. An increase in CQ variability was observed during tube phonation when compared with vowel phonation. Although there was a decrease in the mean CQ values when comparing vowel phonation without vibrato with the other three phonatory tasks, the difference was not statistically significant. Intrasubject analysis demonstrated a decrease in the CQ during tube and vibrato phonation in most of the participants. Although a causal relationship is not proven, this finding suggests that the use of straws and vibrato during phonation may have potential therapeutic value in the treatment of patients with hyperfunctional voice disorders.

Laryngeal and pharyngeal activity during semioccluded vocal tract postures in subjects diagnosed with hyperfunctional dysphonia.

High vertical laryngeal position (VLP), pharyngeal constriction, and laryngeal compression are common features associated with hyperfunctional voice disorders. The present study aimed to observe the effect on these variables of different semioccluded vocal tract postures in 20 subjects diagnosed with hyperfunctional dysphonia. During observation with flexible endoscope, each participant was asked to produce eight different semioccluded exercises: lip trills, hand-over-mouth technique, phonation into four different tubes, and tube phonation into water using two different depth levels. Participants were required to produce each exercise at three loudness levels: habitual, soft, and loud. To determine the VLP, anterior-to-posterior (A-P) compression, and pharyngeal width, a human evaluation test with three blinded laryngologists was conducted. Judges rated the three endoscopic variables using a five-point Likert scale. An intraclass correlation coefficient to assess intrarater and interrater agreement was performed. A multivariate linear regression model considering VLP, pharyngeal width, and A-P laryngeal compression as outcomes and phonatory tasks and intensity levels as predictive variables were carried out. Correlation analysis between variables was also conducted. Results indicate that all variables differ significantly. Therefore, VLP, A-P constriction, and pharyngeal width changed differently throughout the eight semioccluded postures. All semioccluded techniques produced a lower VLP, narrower aryepiglottic opening, and a wider pharynx than resting position. More prominent changes were obtained with a tube into the water and narrow tube into the air. VLP significantly correlated with pharyngeal width and A-P laryngeal compression. Moreover, pharyngeal width significantly correlated with A-P laryngeal compression.

Air Pressure and Contact Quotient Measures During Different Semioccluded Postures in Subjects With Different Voice Conditions.

OBJECTIVE The purpose of this study was to investigate the effect of phonation into tubes in air and tubes submerged in water on air pressure variables and vocal fold adduction in subjects with different voice conditions. METHODS Forty-five participants representing four vocal conditions were included: (1) subjects diagnosed with normal voice and without voice training, (2) subjects with normal voice with voice training, (3) subjects with muscle tension dysphonia, and (4) subjects with unilateral vocal fold paralysis. Participants phonated into different kinds of tubes (drinking straw, 5 mm in inner diameter; stirring straw, 2.7 mm in inner diameter; silicon tube, 10 mm in inner diameter) with the free end in air and in water. Aerodynamic, acoustic, and electroglottographic signals were captured simultaneously. Mean values of the following variables were considered: glottal contact quotient (CQ) measured by electroglottograph, fundamental frequency, subglottic pressure (Psub), oral pressure (Poral), and transglottal pressure. RESULTS All exercises had a significant effect on Psub, Poral, transglottal pressure, and CQ (P < 0.05). Phonation into a 55-cm silicon tube submerged 10 cm in water and phonation into a stirring straw resulted in the highest values for CQ, Psub, and Poral compared with baseline (repetition of syllable [pa:]) for all vocal status. Poral and Psub correlated positively. CONCLUSION During semioccluded exercises, most variables behaved in a similar way (same trend with a quite large individual variation) regardless of the vocal status of the participants.

Immediate acoustic effects of straw phonation exercises in subjects with dysphonic voices

Abstract This study sought to measure any acoustic changes in the speaking voice immediately after phonation exercises involving plastic straws versus phonation exercises with the open vowel /a/. Forty-one primary school teachers with slightly dysphonic voices were asked to participate in four phonatory tasks. Phonetically balanced text at habitual intensity level and speaking fundamental frequency was recorded. Acoustical analysis with long-term average spectrum was performed. Significant changes after therapy for the experimental group include the alpha ratio, L1–L0 ratio and ratio between 1–5 kHz and 5–8 kHz. The results indicate that the use of phonatory tasks with straw exercises can have immediate therapeutic acoustic effects in dysphonic voices. Long-term effects were not assessed in this study.

Laryngoscopic, Acoustic, Perceptual, and Functional Assessment of Voice in Rock Singers

Objective: The present study aimed to vocally assess a group of rock singers who use growl voice and reinforced falsetto. Method: A group of 21 rock singers and a control group of 18 pop singers were included. Singing and speaking voice was assessed through acoustic, perceptual, functional and laryngoscopic analysis. Results: No significant differences were observed between groups in most of the analyses. Acoustic and perceptual analysis of the experimental group demonstrated normality of speaking voice. Endoscopic evaluation showed that most rock singers presented during singing voice a high vertical laryngeal position, pharyngeal compression and laryngeal supraglottic compression. Supraglottic activity during speaking voice tasks was also observed. However, overall vocal fold integrity was demonstrated in most of the participants. Slightly abnormal observations were demonstrated in few of them. Singing voice handicap index revealed that the most affected variable was the physical sphere, followed by the social and emotional spheres. Conclusions: Although growl voice and reinforced falsetto represent laryngeal and pharyngeal hyperfunctional activity, they did not seem to contribute to the presence of any major vocal fold disorder in our subjects. Nevertheless, we cannot rule out the possibility that more evident vocal fold disorders could be found in singers who use these techniques more often and during a longer period of time.

Do Different Semi-Occluded Voice Exercises Affect Vocal Fold Adduction Differently in Subjects Diagnosed with Hyperfunctional Dysphonia?

Objective: To observe the possible differential effects of 8 different semi-occluded vocal tract exercises on glottal contact quotient (CQ) as a measure of vocal fold impact stress. Patients and Methods: Eighty participants were divided into two groups: an experimental group with hyperfunctional dysphonia and a control group of vocally healthy subjects. The participants were recorded before, during and after the exercises. Electroglottographic samples were analyzed to obtain CQ. Results: For the experimental group, all exercises, except lip trills and tongue trills, had an overall significant effect when conditions before, during and after the exercises were compared. The CQ presented differently across the 8 semi-occluded postures during exercise for both groups. For the experimental group, most exercises increased the CQ during practice. Only lip and tongue trills demonstrated lower CQ during exercise. Conclusions: Different semi-occluded exercises differentially affect vocal fold adduction. Lip and tongue trills produced the lowest CQ. Therefore, they may be recommended for decreasing glottal adduction. A straw submerged 10 cm below the water surface presented the greatest CQ. A shallower depth led to a lower CQ, while deeper submersion produced a higher CQ.

Effect on long-term average spectrum of pop singers' vocal warm-up with vocal function exercises.

Abstract This case-control study aimed to investigate if there is any change on the spectral slope declination immediately after vocal function exercises (VFE) vs traditional vocal warm-up exercises in normal singers. Thirty-eight pop singers with perceptually normal voices were divided into two groups: an experimental group (n = 20) and a control group (n = 18). One single session with VFE for the experimental group and traditional singing warm-up exercises for the control group was applied. Voice was recorded before and after the exercises. The recorded tasks were to read a phonetically balanced text and to sing a song. Long-term average spectrum (LTAS) analysis included alpha ratio, L1–L0 ratio, and singing power ratio (SPR). Acoustic parameters of voice samples pre- and post-training were compared. Comparison between VFE and control group was also performed. Significant changes after treatment included the alpha ratio and singing power ratio in speaking voice, and SPR in the singing voice for VFE group. The traditional vocal warm-up of the control group also showed pre–post changes. Significant differences between VFE group and control group for alpha ratio and SPR were found in speaking voice samples. This study demonstrates that VFE have an immediate effect on the spectrum of the voice, specifically a decrease on the spectral slope declination. The results of this study provide support for the advantageous effect of VFE as vocal warm-up on voice quality.

Neuromuscular electrical stimulation of the cricothyroid muscle in patients with suspected superior laryngeal nerve weakness.

In this retrospective case study, we report the apparent clinical effectiveness of neuromuscular electrical stimulation (NMES) in combination with voice therapy (VT) for rehabilitating dysphonia secondary to suspected superior laryngeal nerve (SLN) weakness in two female patients. Both patients failed or plateaued with traditional VT but had significant improvement with the addition of NMES of the cricothyroid muscle and SLN using a VitalStim unit. Stimulation was provided simultaneously with voice exercises based on musical phonatory tasks. Both acoustic analysis and endoscopic evaluation demonstrated important improvements after treatment. In the first patient, the major change was obtained within the primo passaggio region; specifically, a decrease in voice breaks was demonstrated. In the second patient, an improvement in voice quality (less breathiness) and vocal range were the most important findings. Additionally, each patient reported a significant improvement in their voice complaints. Neuromuscular laryngeal electrical stimulation in combination with vocal exercises might be a useful tool to improve voice quality in patients with SLN injury.

Efectos acústicos inmediatos de una secuencia de ejercicios vocales con tubos de resonancia

PURPOSE: the purpose of this study is to determine the immediately acoustic effect of phonatory exercise sequence using resonance tubes in a group of dysphonic subjects METHOD: a unique sequence of four phonatory tasks within resonance tubes was applied in twenty-four teachers with dysphonic voices, assessed perceptually with GRBAS scale. Voice samples were recorded before and after the exercise sequence. Acoustic analysis included the following items: Cepstrum, Jitter, Shimmer, noise-harmonic ratio (NHR). Subjects were asked to fill out a vocal self-assessment protocol after the exercise sequence in order to assess the subjective effects of these exercises. Acoustic parameters of voice samples pre and post training were compared. RESULTS: significant changes were obtained in the Cepstral analysis, jitter and harmonic-to-noise ratio. In the self-assessment, positive effects prevailed over the negative ones, being the main, as follows: more steady voice, more clear voice and more open throat sensation. CONCLUSION: the outcome indicates that the use of phonatory tasks with resonance tubes may have immediate therapeutic physiological effects on subjects with hoarse voices and a subjective perception of improvement in voice production after the therapy.