Zoom in: factors affecting vocal habits during online meetings, a prospective trial on 40 subjects.

PURPOSE: To identify factors that influence vocal habits during online meetings (OMs). METHODS: A prospective trial of forty participants without any known hearing or vocal cord disorders. Subjects participated in an OM divided into six randomly ordered sections, with alterations in audio/speaking equipment and language: the computer's speaker-microphone, a single earbud, two-earbuds or headphones; with/without video, native-language-speaking (Hebrew) versus second language-speaking (English). Each section included free speech, sustained phonation, and a standardized passage. Participants ranked their vocal-effort for each section. Three blinded raters independently scored the voice using the GRBAS scale, and acoustic analyses were performed. RESULTS: No significant difference in self-reported vocal effort was demonstrated between sections. Second-language speaking resulted in significantly increased intensity (p < 0.0001), frequency (p = 0.015), GRBAS (p = 0.008), and strain (p < 0.0001) scores. Using the computer's speaker/microphone resulted in significantly higher strain (p < 0.0001). Using headphones, single or two earbuds resulted in lower intensity and a lower strain score. No differences were detected between OMs with or without video. CONCLUSIONS: Using the computer's microphone/speaker or speaking in a second language during OMs, may result in vocal habits associated with vocal trauma.

Register transitions in an in vivo canine model as a function of intrinsic laryngeal muscle stimulation, fundamental frequency, and sound pressure level.

Phonatory instabilities and involuntary register transitions can occur during singing. However, little is known regarding the mechanisms which govern such transitions. To investigate this phenomenon, we systematically varied laryngeal muscle activation and airflow in an in vivo canine larynx model during phonation. We calculated voice range profiles showing average nerve activations for all combinations of fundamental frequency (F0) and sound pressure level (SPL). Further, we determined closed-quotient (CQ) and minimum-posterior-area (MPA) based on high-speed video recordings. While different combinations of muscle activation favored different combinations of F0 and SPL, in the investigated larynx there was a consistent region of instability at about 400 Hz which essentially precluded phonation. An explanation for this region may be a larynx specific coupling between sound source and subglottal tract or an effect based purely on larynx morphology. Register transitions crossed this region, with different combinations of cricothyroid and thyroarytenoid muscle (TA) activation stabilizing higher or lower neighboring frequencies. Observed patterns in CQ and MPA dependent on TA activation reproduced patterns found in singers in previous work. Lack of control of TA stimulation may result in phonation instabilities, and enhanced control of TA stimulation may help to avoid involuntary register transitions, especially in the singing voice.

Effect of physical frailty on maximum phonation time in community-dwelling older individuals who visited a neurology outpatient clinic.

BACKGROUND: Maximum phonation time (MPT) is used to assess speech and other oral rehabilitation-related issues. Various factors contribute to MPT decline in older individuals. Although the impact of physical frailty on MPT has been suggested, this has not been conclusively determined. OBJECTIVE: To examine the relationship between MPT and physical frailty in community-dwelling individuals aged ≥60 years who were independently mobile. MPT-associated factors were investigated. METHODS: This cross-sectional study analysed the clinical data of 122 patients (age [interquartile range]: 80.0 [74.0-83.0] years) without dementia who visited a neurology department between 1 February 2021 and 31 January 2023. Investigated factors included age, sex, weight, height, body mass index, smoking history, grip strength, functional independence measure, vital capacity, oral diadochokinesis, MPT and the Japanese Cardiovascular Health Study score. Physical frailty was assessed based on the total score from five items (weight loss, weakness, exhaustion, slowness and low physical activity). The relationship between MPT and physical frailty was examined using Spearman's rank correlation coefficient and hierarchical multiple regression analysis. RESULTS: The MPT was negatively correlated with age (r = -0.347, p < .01) and physical frailty (r = -0.681, p < .01) and positively correlated with vital capacity (r = 0.474, p < .01) and height (r = 0.248, p < .01). The hierarchical multiple regression analysis, conducted with MPT as the dependent variable, demonstrated that physical frailty (ß = -.59, 95% confidence interval: -0.74 to 0.43, p < .001) had a strong influence on MPT. CONCLUSION: In older individuals, MPT is associated with physical frailty. When assessing MPT in clinical settings, it is advisable to perform a concurrent assessment of physical frailty.

Systematic Review of Literature on Vocal Demand Response: Understanding Physiology, Measurements, and Associated Factors.

PURPOSE: Considering the conceptual migration from vocal load and vocal loading to vocal demand and vocal demand response, this review of literature aimed to identify physiological explanations, reported measurements, and associated factors (vocal demands) reported in the literature when considering the phonatory response to a vocal demand. METHODS: A systematic review of literature, following the PRISMA Statement, was conducted using Web of Science, PubMed, Scopus, and ScienceDirect. Data were analyzed and presented in two parts. First, a bibliometric analysis, co-occurrence analysis, and content analysis were performed. Three criteria that got article inclusion were defined: (1) written in English, Spanish, and Portuguese; (2) published between 2009 and 2021; and (3) focused on vocal load and loading, vocal demand response, and voice assessment parameters. A total of 54 publications met the criteria and were included in this review. The second part included a conceptual framework based on the content analysis of three aspects of vocal demand response: (1) physiological explanations, (2) reported measurements, and (3) vocal demands. RESULTS AND CONCLUSION: As would be expected since vocal demand response is a relatively new term and not yet commonly used in literature when discussing way that the speakers respond to communicative scenarios, most of the studies reviewed (both historical and recent) still use the term of vocal load and vocal loading. Although there is a broad variety of literature discussing a wide range of vocal demands and voice parameters used to characterize the vocal demand response, results show that there is consistency across the studies. While vocal demand response is unique and intrinsic to the talker, associated factors that contribute to this response include both internal talker and external talker factors. Internal factors include muscle stiffness, viscosity in the phonatory system, vocal fold tissue damage, elevated sound pressure levels during occupational voice demands, extended periods of voice use, suboptimal body posture, difficulties in breathing technique, and sleep disturbances. Associated external factors include the working environment (noise, acoustics, temperature, humidity). In conclusion, although vocal demand response is intrinsic to the speaker, the speaker's response is affected by external vocal demands. However, due to the wide methods to evaluate vocal demand response, it has been difficult to establish its contribution to voice disorders in the general population and, specifically, among occupational voice users. This literature review identified commonly reported parameters and factors that may help clinicians and researchers define vocal demand response.

Changes in and clinical utility of maximum phonation time and repetitive saliva swallowing test scores after esophagectomy.

BACKGROUND: Postoperative pneumonia in patients with esophageal cancer occurs due to swallowing dysfunction and aspiration. Recently, maximum phonation time (MPT) assessment and repetitive saliva swallowing test (RSST) have been focused on as swallowing function assessment methods that can identify patients as high risk for pneumonia. We aimed to evaluate the clinical utility of MPT assessment and RSST in patients undergoing oncological esophagectomy. METHODS: In total, 47 consecutive patients who underwent esophagectomy for esophageal cancer between August 2020 and July 2023 were eligible. The perioperative changes in MPTs and RSST scores were examined. In addition, univariate and multivariate analyses were performed to identify the predictive factors of postoperative pneumonia. RESULTS: The median MPTs before surgery and on postoperative days (PODs) 3, 6, and 10 were 18.4, 7.2, 10.6, and 12.4 s, respectively; postoperative MPTs were significantly lower than preoperative MPT. In addition, the MPT of POD 6 was significantly longer than that of POD 3 (P < 0.05). Meanwhile, there were no significant changes in perioperative RSST scores. Overall, 8 of 47 patients (17.0%) developed pneumonia postoperatively. A short MPT on POD 6 was one of the independent predictive factors for the incidence of postoperative pneumonia (odds ratio: 12.6, 95% confidence interval: 1.29-123, P = 0.03) in the multivariate analysis. CONCLUSIONS: The MPT significantly decreased after esophagectomy. However, the RSST score did not. The MPT on POD6 can be a predictor of postoperative pneumonia.

Maximum phonation time: an independent predictor of late-onset pneumonia after esophageal cancer surgery.

Dysphagia after esophagectomy is a major risk factor for aspiration pneumonia, thus preoperative assessment of swallowing function is important. The maximum phonation time (MPT) is a simple indicator of phonatory function and also correlates with muscle strength associated with swallowing. This study aimed to determine whether preoperative MPT can predict postoperative aspiration pneumonia. The study included 409 consecutive patients who underwent esophagectomy for esophageal cancer between 2017 and 2021. Pneumonia detected by routine computed tomography on postoperative days 5-6 was defined as early-onset pneumonia, and pneumonia that developed later (most often aspiration pneumonia) was defined as late-onset pneumonia. The correlation between late-onset pneumonia and preoperative MPT was investigated. Patients were classified into short MPT (<15 seconds for males and <10 seconds for females, n = 156) and normal MPT groups (≥15 seconds for males and ≥10 seconds for females, n = 253). The short MPT group was significantly older, had a lower serum albumin level and vital capacity, and had a significantly higher incidence of late-onset pneumonia (18.6 vs. 6.7%, P < 0.001). Multivariate analysis showed that short MPT was an independent risk factor for late-onset pneumonia (odds ratio: 2.26, P = 0.026). The incidence of late-onset pneumonia was significantly higher in the short MPT group (15.6 vs. 4.7%, P = 0.004), even after propensity score matching adjusted for clinical characteristics. MPT is a useful predictor for late-onset pneumonia after esophagectomy.

The effect of type 1 diabetes mellitus on voice in pediatric patients.

PURPOSE: The aim of this prospective case-control study was to determine the effect on the voice of type 1 diabetes mellitus (T1DM) in paediatric patients. MATERIALS AND METHODS: The study included patients aged 6-18 years followed up for at least 1 year because of T1DM, and a control group of age and gender-matched healthy volunteers. Following an Ear, Nose, and Throat (ENT) examination, all subjects underwent flexible endoscopic laryngeal examination. Fasting venous blood samples were taken in the morning for the examination of fasting blood glucose (FBG), HgbA1C, and kidney, liver, and thyroid function tests. Data were recorded from the patient files of age, gender, comorbidities, and the development of diabetes-related complications. Voice recordings were taken and the Voice Handicap Index (VHI)-10 form was completed. The patients and control group were compared in respect of the parameters of fundamental frequency, jitter, shimmer, and acoustic voice quality index (AVQI). RESULTS: Evaluation was made of 64 children and adolescents as 32 in the patient group (Group 1) and 32 healthy control subjects (Group 2). Group 1 comprised 17 females and 15 males with a mean age of 12.75 ± 3.23 years. Group 2 comprised 17 females and 15 males with a mean age of 12.75 ± 3.33 years. In Group 1, mean disease duration was 5.21 ± 3.17 years (range, 1-13 years), the FBG value was mean 216.6 ± 122.3 mg/dl, mean HgbA1c was 10.7 ± 2.8, as ≤ 7 in 4 patients, 7-9 in 4, and > 9 in 24. Maximum phonation time (MPT) was determined as 10.66 ± 3.6 secs in Group 1 and 12.11 ± 4.43 in Group 2. VHI was determined as 2.33 ± 3 in Group 1 and 2.31 ± 2.77 in Group 2. No statistically significant difference was determined between the groups was determined in respect of acoustic analysis, perturbation parameters, AVQI and body mass index. CONCLUSIONS: This study is the first to have investigated the effects of T1DM on the voice in paediatric patients. The study results showed that the AVQI value was higher in the patient group but not to a statistically significant level. Therefore, there is a need for further studies with larger samples. The current study can be of guidance for further studies in this field.

An experimental model of the pharyngoesophageal segment in tracheoesophageal phonation.

Tracheoesophageal (TE) speech is an important method of speech rehabilitation for those who undergo a total laryngectomy. Despite the many advantages over other methods, there is still room for improvement in terms of the overall quality of the TE voice as well as its success rate. These points could be greatly assisted by an improved knowledge on the mechanics of TE speech. Here, an experimental model of the pharyngoesophageal segment (PES), based on the idea of a collapsible tube, is proposed. To implement the model, considerable simplifications had to be made, most notably in the use of a thin flexible tube to represent the PES. The model was used to assess the minimum amount of tonicity required for the onset of phonation in terms of the flow rate and longitudinal tension. Additionally, comparisons with a mathematical model [Tourinho, da Silva, dos Santos, Thomaz, and Vieira, J. Acoust. Soc. Am. 149, 1979-1988 (2021)] have been made, yielding similar trends for sufficiently large flow rates. The measurements also suggest that the phonation frequency is most affected by the tonicity of the PES, which highlights the question of which physiological mechanism is responsible for the control of the fundamental frequency of phonation.

The influence of source-filter interaction on the voice source in a three-dimensional computational model of voice production.

The goal of this computational study is to quantify global effects of vocal tract constriction at various locations (false vocal folds, aryepiglottic folds, pharynx, oral cavity, and lips) on the voice source across a large range of vocal fold conditions. The results showed that while inclusion of a uniform vocal tract had notable effects on the voice source, further constricting the vocal tract only had small effects except for conditions of extreme constriction, at which constrictions at any location along the vocal tract decreased the mean and peak-to-peak amplitude of the glottal flow waveform. Although narrowing in the epilarynx increased the normalized maximum flow declination rate, vocal tract constriction in general slightly reduced the source strength and high-frequency harmonic production at the glottis, except for a limited set of vocal fold conditions (e.g., soft, long vocal folds subject to relatively high pressure). This suggests that simultaneous laryngeal and vocal tract adjustments are required to maximize source-filter interaction. While vocal tract adjustments are often assumed to improve voice production, our results indicate that such improvements are mainly due to changes in vocal tract acoustic response rather than improved voice production at the glottis.

Effect of functional electric stimulation on phonation in an ex vivo aged ovine model.

With age, the atrophy of the thyroarytenoid muscle (TAM), and thus atrophy of the vocal folds, leads to decreased glottal closure, increased breathiness, and a loss in voice quality, which results in a reduced quality of life. A method to counteract the atrophy of the TAM is to induce hypertrophy in the muscle by functional electric stimulation (FES). In this study, phonation experiments were performed with ex vivo larynges of six stimulated and six unstimulated ten-year-old sheep to investigate the impact of FES on phonation. Electrodes were implanted bilaterally near the cricothyroid joint. FES treatment was provided for nine weeks before harvesting. The multimodal measurement setup simultaneously recorded high-speed video of the vocal fold oscillation, the supraglottal acoustic signal, and the subglottal pressure signal. Results of 683 measurements show a 65.6% lower glottal gap index, a 22.7% higher tissue flexibility (measured by the amplitude to length ratio), and a 473.7% higher coefficient of determination (R2) of the regression of subglottal and supraglottal cepstral peak prominence during phonation for the stimulated group. These results suggest that FES improves the phonatory process for aged larynges or presbyphonia.

Verifying Efficacy of Self-Inhalation Training for Velopharyngeal Dysfunction.

Velopharyngeal closure in healthy adults during different tasksObjective: Velopharyngeal dysfunction causes not only resonance problems (so-called "hypernasality") but also dysphagia, particularly in the elderly. In our previous study, we developed a new inhaling training method to objectively improve velopharyngeal function using the measurement of peak inspiratory flow (PIF) rate, which was effective in all patients. In this study, we clarify the degree of velopharyngeal closure to determine the efficacy of our training to improve the closure mechanism. METHODS: Three healthy volunteers performed tasks in a magnetic resonance imaging (MRI) gantry in the supine position. To confirm velopharyngeal function, volunteers were first asked to distinguish the difference in the velum position between the production of a nonnasal (sustained phonation /shi:/) and a nasal (sustained phonation /n:/) sound. They were then asked to inhale forcefully through the mouth from an empty 500-mL plastic bottle. For comparison, volunteers performed exhaling forcefully, then inhaling and exhaling softly, through a straw. Each task was performed for 30 s, and the MRI images were obtained in sagittal sections. RESULTS: Inhaling forcefully from an empty plastic bottle created the strongest velopharyngeal closure between the posterior surface of the velum (soft palate) and the posterior pharyngeal wall in all volunteers. CONCLUSION: The results of our MRI study supported our training method. Using inhalation through a PIF meter or from a plastic bottle to create resistance strengthens particularly the levator veli palatini muscle for velopharyngeal closure, which may be useful in patients with other acquired velopharyngeal dysfunctions including physiological aging. Also, anyone anywhere can train with plastic bottles.

Synthetic mucus for an ex vivo phonation setup: Creation, application, and effect on excised porcine larynges.

Laryngeal mucus hydrates and lubricates the deformable tissue of the vocal folds and acts as a boundary layer with the airflow from the lungs. However, the effects of the mucus' viscoelasticity on phonation remain widely unknown and mucus has not yet been established in experimental procedures of voice research. In this study, four synthetic mucus samples were created on the basis of xanthan with focus on physiological frequency-dependent viscoelastic properties, which cover viscosities and elasticities over 2 orders of magnitude. An established ex vivo experimental setup was expanded by a reproducible and controllable application method of synthetic mucus. The application method and the suitability of the synthetic mucus samples were successfully verified by fluorescence evidence on the vocal folds even after oscillation experiments. Subsequently, the impact of mucus viscoelasticity on the oscillatory dynamics of the vocal folds, the subglottal pressure, and acoustic signal was investigated with 24 porcine larynges (2304 datasets). Despite the large differences of viscoelasticity, the phonatory characteristics remained stable with only minor statistically significant differences. Overall, this study increased the level of realism in the experimental setup for replication of the phonatory process enabling further research on pathological mucus and exploration of therapeutic options.

Velocity differences in laryngeal adduction and abduction gestures.

The periodic repetitions of laryngeal adduction and abduction gestures were uttered by 16 subjects. The movement of the cuneiform tubercles was tracked over time in the laryngoscopic recordings of these utterances. The adduction velocity and abduction velocity were determined objectively by means of a piecewise linear model fitted to the cuneiform tubercle trajectories. The abduction was found to be significantly faster than the adduction. This was interpreted in terms of the biomechanics and active control by the nervous system. The biomechanical properties could be responsible for a velocity of abduction that is up to 51% higher compared to the velocity of adduction. Additionally, the adduction velocity may be actively limited to prevent an overshoot of the intended adduction degree when the vocal folds are approximated to initiate phonation.

Contribution of laryngeal size to differences between male and female voice production.

In this study we investigated the effect of sex- and age-related differences in vocal fold length, thickness, and depth on voice production in a three-dimensional vocal fold model. The results showed that the cause-effect relationships between vocal fold physiology and voice production previously identified in an adult male-like vocal fold geometry remained qualitatively the same in vocal folds with geometry representative of adult females and children. We further showed that the often-observed differences in voice production between adult males, adult females, and children can be explained by differences in length and thickness. The lower F0, higher flow rate, larger vocal fold vibration amplitude, and higher sound pressure level (SPL) in adult males as compared to adult females and children can be explained by differences in vocal fold length. In contrast, the thickness effect dominated and contributed to the larger closed quotient of vocal fold vibration, larger normalized maximum flow declination rate, and lower H1-H2 in adult males as compared to adult females and children. The effect of differences in vocal fold depth was generally small. When targeting a specific SPL, adult males experienced a lower peak vocal fold contact pressure during phonation than adult females and children.

The effectiveness of voice therapy on voice-related handicap: A network meta-analysis.

BACKGROUND: Treatment approaches for voice therapy are diverse, yet their differential effects are not well understood. Evaluations of treatment effects across approaches are important for clinical guidance and evidence-based practice. OBJECTIVE OF REVIEW: To quantify the evidence of treatment effectiveness on the outcome measure Voice Handicap Index with the 30-items (VHI-30) from existing randomised controlled/clinical trials (RCT) of voice therapy using the statistical approach of a network meta-analysis (NMA) with a random effects model. TYPE OF REVIEW: Meta-analysis. SEARCH STRATEGY: We searched in MEDLINE (PubMed, 1950 to 2019), Embase (1974 to 2019) and Science Citation Index (1994 to 2019) using five key terms. The inclusion criteria were reports of randomised controlled/clinical trials (RCTs) published in English or German which evaluated the effectiveness of a specific voice therapy treatment using VHI-30 as an outcome measure in adult participants with non-organic or organic voice disorders. Studies were excluded if participants had been diagnosed with neurological motor speech disorders or who were vocally healthy. Furthermore, no medical, pharmacological or instrumental (eg voice amplification) treatments were considered. EVALUATION METHOD: The primary outcome variable was VHI-30 with a score from 0 to 120. The pre-post treatment change in VHI-30 scores was an average score of 13 points related to various VHI-30 test-retest results. RESULTS: We retrieved 464 publications (ie with duplicates) and included 13 RCTs, which evaluated nine interventions, in the final analysis. The most effective intervention with a significant and clinically relevant effect was Stretch-and-Flow Phonation (SFP) (mean pre-post difference -28.37, 95% confidence interval [CI], -43.05 to-13.68). Resonant Voice (RV), the Comprehensive Voice Rehabilitation Program (CVRP) and Vocal Function Exercises (VFE) also demonstrated significant improvements. CONCLUSIONS: Of the nine voice interventions identified with the present NMA, SFP, RVT, CVRP, and VFE effectively improved VHI-30 scores from pre- to post-treatment. SFP proved to be the most significant and clinically relevant treatment. Further contributions of high-quality intervention studies are needed to support evidence-based practice in vocology.

Estimating vocal fold stiffness: Using the relationship between subglottic pressure and fundamental frequency of phonation as an analog.

OBJECTIVE: The stiffness of the vocal folds is an important factor in voice production, yet clinically applicable measurements are still lacking. It has been demonstrated in an in vivo canine model that fundamental frequency (F0 ) increased linearly as subglottic pressure (Ps ) increased, but with a lesser slope for higher levels of vocal fold tension. In this study, the relationship between F0 and Ps was investigated using the airflow interruption method in awake patients non-invasively. DESIGN: Healthy volunteers enrolled for evaluation. SETTING: Single-centre. PARTICIPANTS: Thirty-three healthy volunteers aged 20 and older were recruited, with one excluded for a recent asthma attack. MAIN OUTCOME MEASURES: The relationships between F0 and Ps , described as the slope (Hz/kPa), were investigated when the participants sustained voicing the vowel/o/at 3 incremental frequencies 4 semitones apart in the modal register (F1, F2 and F3). RESULTS: Thirty-two healthy volunteers (20 females, 12 males) aged 20-47 years were enrolled for final analyses. There was a statistically significant difference in the slopes of the linear regression lines of F0 -Ps , depending on the frequency with which the vowel/o/ was produced (P < .001). The slope differed significantly between F2 and F1 (P < .001; P = .015), F3 and F1 (P < .001; P = .002) and F3 and F2 (P < .001; P = .005) for both women and men, respectively. CONCLUSIONS: It was demonstrated that the higher the vocal fold tension, the smaller the slope between F0 and Ps . Using the relationship between F0 and Ps as an analog of vocal fold stiffness is potentially practical for clinical application.

Speech profiles of Spanish-Catalan children with developmental language disorder.

Children with developmental language disorders (DLD) are especially characterised by morphosyntactic difficulties. Nevertheless, previous studies have also shown that children with DLD have phonological difficulties. This paper aims to describe the productive and perceptive phonological speech profile of Spanish-Catalan children with DLD at the age of six in order to characterise the underlying nature of their difficulties. Fourteen Spanish-Catalan six-year-old children with DLD and 14 control children without language difficulties who attended the same class were assessed with the screening and discrimination tasks of the A-RE-HA: Análisis del Retraso del Habla (Speech Delay Analysis - Catalan and Spanish version). We analysed the production of words, syllables and phonemes, phoneme discrimination and phonological simplification processes used by these children. The results showed that children with DLD have a lower percentile in correct word structures, syllabic structures and phonemes, and have more difficulty discriminating phonemes. Detailed analyses revealed more difficulties with the most complex word and syllabic templates, and with almost all phonemes. Furthermore, children with DLD applied more phonological simplification processes than the control group. An individual analysis showed that only ten of the children with DLD also had a speech delay (percentile < 25), while four had scores in line with their age. These results show that most of the six-year-old children with DLD maintain speech difficulties, which are mainly phonological and not (or not only) articulatory. Therefore, individual differences with respect to speech delay in DLD must be taken into consideration to better detect these children.

Effects of a simulated system of straw phonation on the complete phonatory range of excised canine larynges.

PURPOSE: This study investigated the effects of straw phonation therapy on the aerodynamic and acoustic parameters of the vocal folds at different levels of elongation and subglottal pressure. METHODS: 20 excised canine larynges were used in both experimental (straw phonation therapy simulation) and control conditions. Aerodynamic parameters, including phonation threshold pressure (PTP), phonation instability pressure (PIP), phonation pressure range (PPR), phonation threshold flow (PTF), phonation instability flow (PIF), phonation flow range (PFR), were obtained at different levels of vocal fold elongation (0%, 10%, 20%). Acoustic parameters, including fundamental frequency (F0), jitter, shimmer, signal noise ratio (SNR) were detected at different levels of vocal fold elongation (0%, 10%, 20%) and subglottal pressure (15 cmH2O, 20 cmH2O, 25 cmH2O). RESULTS: Significant decreases in PTP and PTF and significant increases in PIP, PIF, PPR, and PFR occurred in experimental condition at all levels of elongation when compared with control condition. However, no significant changes of acoustic parameters were obtained between conditions at all levels. CONCLUSION: At different levels of vocal fold elongation, straw phonation not only lowered the onset of normal voice, but also elevated the onset of chaotic voice, indicating a better voice economy and voice control. Moreover, the improved phonatory range demonstrated that straw phonation had the potential to prevent voice users who have high voice demand from voice fatigue and vocal damage.

A systematic review of current methodology of high resolution pharyngeal manometry with and without impedance.

PURPOSE: This systematic review appraises and summaries methodology documented in studies using high resolution pharyngeal manometry (HRM) with and without impedance technology (HRIM) in adult populations. METHODS: Four electronic databases CINAHL, EMBASE, MEDLINE, and Cochrane Library were searched up to, and including March 2017. Studies reporting pharyngeal HRM/HRIM for swallowing and/or phonatory assessment, published in peer-reviewed journals in English, German, or Spanish were assessed for the inclusion criteria. Of the selected studies, methodological aspects of data acquisition and analysis were extracted. Publications were graded based on their level of evidence and quality of methodological aspects was assessed. RESULTS: Sixty-two articles were identified eligible, from which 50 studies reported the use of HRM and 12 studies used HRIM. Of all included manuscripts, the majority utilized the ManoScan™ system (64.5%), a catheter diameter of 4.2 mm was most prevalently documented (30.6%). Most publications reported the application of topical anesthesia (53.2%). For data analysis in studies using HRM, software intrinsic to the recording system was reported most frequently (56%). A minority of the studies using HRM provided data about measurement reliability (10%). This is higher for studies using HRIM (50%). CONCLUSIONS: Considerable methodological variability exists regarding data acquisition and analysis in published studies using HRM/HRIM. Lacking reports of methodology make study replications difficult and reduce the comparability across studies. More data regarding the impact of individual methodological aspects on study outcomes are further required for the development of methodological recommendations.

Three-dimensional imaging of vocalizing larynx by ultra-high-resolution computed tomography.

PURPOSE: Ultra-high-resolution computed tomography (UHRCT) is an emerging imaging technology that is able to achieve simultaneous 160 slices with super-thin 0.25 mm thickness. The purpose of this study was to assess the feasibility of UHRCT to visualize laryngeal structure and kinetics. METHODS: Three normal volunteers and three patients with unilateral vocal fold paralysis (UVFP) were incorporated in this case series. First, images were taken under five conditions in normal volunteers. Five tasks consisted of (1) air inspiration through the nose (IN), (2) breath holding (BH), (3) sustained vowel /i:/ phonation (IP), (4) humming phonation (HP), and (5) forced glottic closure during exhalation (FC). Three-dimensional CT images of arytenoid and cricoid cartilages, as well as virtual laryngoscopic images, were reconstructed using UHRCT data. Reconstructed images were compared among five conditions to assess the best tasks to picture laryngeal kinetics. Second, pre- and post-phonosurgical images were examined in UVFP patients to evaluate potential role of UHRCT to assess laryngeal pathology in hoarse patients. RESULTS: Among the five conditions, IN and IP conditions were considered suitable to visualize laryngeal structure at rest and during phonation, respectively. Kinetic abnormalities including asymmetric motion of arytenoid cartilages were elucidated in UVFP patients, and virtual endoscopy visualized the clinically invisible posterior three-dimensional glottic chinks. Furthermore, UHRCT was useful to understand changes in laryngeal structure achieved by phonosurgery. CONCLUSIONS: UHRCT is an emerging imaging technology that can be used for minimally invasive visualization and assessment of laryngeal structure and kinetics. Future studies to assess more number of patients with laryngeal dysfunction are warranted.