Glottal Area Research Articles

Computational Study of the Impact of Dehydration-Induced Vocal Fold Stiffness Changes on Voice Production

Systemic vocal fold dehydration is known to increase vocal fold stiffness, which has been hypothesized to have important effect on voice production. However, it remains unclear whether the dehydration-induced vocal fold stiffness changes can have a noticeable impact on phonation, particularly in normal phonation conditions. The goal of this study was to investigate the impact of vocal fold stiffness changes due to vocal fold systemic dehydration and its significance in daily communication. Parametric computational simulation using a three-dimensional vocal fold model, in which the vocal fold stiffness was varied as a function of systemic dehydration levels based on previously-reported experimental data. The results showed that systemic dehydration had significant effects on voice production only at high levels of dehydration, at which dehydration increased the phonation threshold pressure and fundamental frequency, and decreased glottal opening area, vocal intensity and glottal efficiency. The effect depended mainly on the overall dehydration level but was also slightly affected by the dehydration distribution and muscular control. However, for dehydration levels typical of normal phonation conditions, the effect was negligible. The results indicated that dehydration-induced vocal fold stiffness change likely is not an important mechanism through which vocal fold systemic dehydration affects voice production. Nevertheless, a large decrease in glottal efficiency implies a possible perceived increase of vocal effort under a realistic dehydration condition.

Comparison of two external manoeuvres with the conventional technique on glottic visualisation using a C-MAC® videolaryngoscope in children for elective surgery

Background and Aims:Glottic visualization is a pre-requisite for successful intubation. We compared the effect of backward upward rightward pressure (BURP) and jaw thrust manoeuvres with the conventional technique on glottic visualisation using a C-MAC® videolaryngoscope in children of 3 to 10 years.Methods:Ninety children of either gender of 3 to 10 years with normal airways and of the American Society of Anesthesiologists grade I or II for elective surgery under general anaesthesia with endotracheal intubation using a C-MAC® videolaryngoscope were enroled. Glottic views with the conventional technique (C), BURP (B), and jaw thrust (J) manoeuvres in three groups were assessed by modified Cormack Lehane grade (MCL) grade, percentage of glottic view (POGO) score, and a new two-dimensional metric – approximate glottic opening area in pixels squared. Approximate glottic opening area calculations were performed using tool pencil in horos medical imaging software.Results:Jaw thrust had statistically significant superiority over the conventional technique and BURP on glottic visualisation (a p value of C vs J < 0.0001 and B vs J < 0.05 for all the three parameters). BURP was comparable to the conventional technique in MCL grade and POGO score (a p value of C vs B > 0.05) but was superior to the conventional technique in glottic area (a p value of C vs B = 0.013).Conclusion:Jaw thrust enhanced glottic visualisation by maximising all the glottic view parameters as compared to the BURP manoeuvre and the conventional technique and should be considered the primary manoeuvre to aid intubation in children.Glottic Area (pixels squared)C (n=90)B (n=90)J (n=90)Total P C vs BC vs JB vs JMean±SD3969.64±2180.884657.19±1994.875508.12±2036.954711.65±2158.81<.00010.013<.00010.006Median (25th-75th percentile)3469.79 (2356.025-5193.743)4452.7 (3238.408-5482.152)5332.83 (4157.038-6904.62)4419.82 (3065.835-5821.836)Range639.02-9996.47638.23-9467.261603.95-9848638.23-9996.47

Relationship Between Oropharyngeal Geometry and Vocal Parameters in Subjects With Parkinson's Disease

To verify whether the dimensions of different segments of the oropharyngeal cavity have different proportions between Parkinson's disease patients and vocally healthy subjects and investigate whether the measurements of these subjects' oropharyngeal geometry associate with their acoustic measurements of voice. Quantitative, descriptive, cross-sectional, and retrospective study with secondary data, approved by the Human Research Ethics Committee under no. 4.325.029. We used vocal samples and data from the oropharyngeal geometry of 40 subjects - 20 with Parkinson's disease stages I to III and 20 who formed the control group, matched for sex and age. Each group had 10 males and 10 females, mean age of 61 years (±6.0). Formant (F1, F2, and F3) and cepstral measures of the sustained vowel /ε/ were extracted and arranged in the database to determine their values using Praat software. The data were descriptively analyzed, with statistics generated with R software. The proportion of oropharyngeal geometry measurements was arranged by mean values and coefficients of variation. Pearson's linear correlation test was applied to relate voice parameters to oropharyngeal geometry, considering P < 0.05, and linear regression test, to justify F2. The Parkinson's disease group showed a linear relationship between oral cavity length and F1 in males (P = 0.04) and between glottal area and F2 in females (P = 0.00); linear relationships were established according to age in both groups, and a regression model for F2 was estimated (R2 = 0.61). There was no difference between pathological and healthy voices; there was a difference in the proportional relationship of oropharyngeal geometry between the groups. The proportional relationship of oropharyngeal geometry differs between the Parkinson's disease group and the control group, as well as the relationship between oropharyngeal geometry and formant and cepstral values of voice according to the subjects' sex and age.

Pressure, Flow, and Glottal Area Waveform Profile Changes During Phonation Using the Acapella Choice Device

Vibratory positive expiratory pressure (PEP) devices are now commonly used as a resource for voice therapy. PEP devices promote improved vocal economy with the added benefit of producing a massage effect in the vocal tract. Although the benefits of PEP devices for voice have already been demonstrated, their impact on the vocal source is still not very clear. This study assesses the impact of phonation into the Acapella Choice (a type of PEP device) on the voice. Three normophonic subjects underwent high-speed videoendoscopy assessment while pressure, flow and electroglottographic data was collected. Phonation into the Acapella device produces large changes in the pressure and flow profiles consequently affecting the voice source. In specific, when intraoral pressure increases as a consequence of the downward movement of the rocker arm in the Acapella device (reduction of the airflow outlet), phonation is hindered, demonstrated by the lower amplitude of vibration of the vocal folds and weaker modulation of the pressure and flow values by the glottal cycle. When the rocker arm in the Acapella device opens (increasing the airflow outlet), the opposite trend is observed where vocal fold vibration is aided and the modulation of pressure and flow by the vocal cycle increases. Based on the pressure and flow signals, we can assume that the impedance of the vocal tract alternates between two dominant regimes: increased inertive reactance (aided vibration) and increased resistance (hindered vibration). PEP devices, such as the Acapella device, are efficient in modulating the pressure and flow profiles in the vocal tract leading to the alternation of glottal vibration from aided to hindered. These changes in the glottal vibration can be considered an additional consequence of the massage effect caused by the Acapella device.

Segmentation of Glottal Images from High-Speed Videoendoscopy Optimized by Synchronous Acoustic Recordings.

Laryngeal high-speed videoendoscopy (LHSV) is an imaging technique offering novel visualization quality of the vibratory activity of the vocal folds. However, in most image analysis methods, the interaction of the medical personnel and access to ground truth annotations are required to achieve accurate detection of vocal folds edges. In our fully automatic method, we combine video and acoustic data that are synchronously recorded during the laryngeal endoscopy. We show that the image segmentation algorithm of the glottal area can be optimized by matching the Fourier spectra of the pre-processed video and the spectra of the acoustic recording during the phonation of sustained vowel /i:/. We verify our method on a set of LHSV recordings taken from subjects with normophonic voice and patients with voice disorders due to glottal insufficiency. We show that the computed geometric indices of the glottal area make it possible to discriminate between normal and pathologic voices. The median of the Open Quotient and Minimal Relative Glottal Area values for healthy subjects were 0.69 and 0.06, respectively, while for dysphonic subjects were 1 and 0.35, respectively. We also validate these results using independent phoniatrician experts.

Computational Analysis of the Droplet-Stimulated Laryngeal Adductor Reflex in High-Speed Sequences.

The laryngeal adductor reflex (LAR) is an important protective mechanism of the airways. Its physiology is still not completely understood. The available methods for LAR evaluation offer limited reproducibility and/or rely on subjective interpretation. A new approach, termed Microdroplet Impulse Testing of the LAR (MIT-LAR), was recently introduced. Here, the LAR is elicited by a droplet and a laryngoscopic high-speed recording is acquired simultaneously. In the present work, image-processing algorithms for autonomous MIT-LAR sequence analysis were developed. This allowed the automated approximation of kinematic LAR parameters in humans. Development and testing of computational methods. Computational image processing enabled the autonomous estimation of the glottal area, the glottal angle, and the vocal fold edge distance in MIT-LAR sequences. A suitable analytical representation of these glottal parameters allowed the extraction of seven relevant LAR parameters. The obtained values were compared to the literature. A generalized logistic function showed the highest average goodness of fit among four different analytical approaches for each of the glottal parameters. Autonomous sequence analysis yielded bilateral LAR response latencies of (229 ± 116) ms and (182 ± 60) ms for cases of complete and incomplete glottal closure, respectively. The initial/average/maximum angular vocal fold adduction velocity was estimated at (157 ± 115) °s-1 /(891 ± 516) °s-1 /(929 ± 583) °s-1 and (88 ± 53) °s-1 /(421 ± 221) °s-1 /(520 ± 238) °s-1 for complete and incomplete glottal closure, respectively. The automated extraction of LAR parameters from laryngoscopic high-speed sequences can potentially increase the objectiveness of optical LAR characterization and reduce the associated workload. The proposed methods may thus be helpful for future research on this vital reflex. NA Laryngoscope, 132:2412-2419, 2022.

TREATMENT OF EARLY GLOTTIC CARCINOMA WITH TRANSORAL ENDOSCOPIC LASER SURGERY.

Laryngeal carcinoma is one of the most common tumors of the head and neck, just after skin cancer. Alongside open surgery, transoral endoscopic laser surgery (TOLS) has become widespread as a treatment method. Our aim was to assess the efficacy of transoral laser cordectomy in a group of patients with early glottic carcinoma. We retrospectively analyzed data on 131 patients who underwent TOLS in the 2017-2021 period. We divided patients into groups according to tumor stage and type of cordectomy performed, and compared outcomes between the groups. Our results revealed a higher number of patients in the group with Tis and T1a than in those with T1b and T2 who underwent type III cordectomy, and also a higher number of those for whom outpatient follow-ups were sufficient after surgery in the same group. We did not observe significant difference in outcomes according to cordectomy type except for type V (a-d), where a higher number of patients had to undergo radiotherapy. This study underlines the importance of careful patient selection for TOLS, as well as the need for close cooperation with pathology and radiology specialists to ensure optimal approach and extent of surgery for each individual patient. It also displayed TOLS as a sound therapeutic option for early stages of glottic carcinoma but also indicated the need for similar studies in a larger number of patients to elucidate the effectiveness in certain glottis areas.

A study comparing either using intravenous propofol or topical lidocaine over the larynx as adjuncts to inhalational induction of anesthesia for facilitating nasotracheal intubation for pediatric patients undergoing tonsillectomy surgery

Background Nasotracheal intubation in tonsillectomy surgery is used to facilitate surgical exposure. Intubation without muscle relaxant is commonly practiced for pediatric patients in ambulatory surgeries. Using adjuncts to inhalational induction makes more suitable conditions for intubation with hemodynamic stability and less laryngeal morbidities. In this study, lidocaine, 1% was used topically on vocal cords to facilitate nasotracheal intubation in comparison with intravenous propofol after inhalational induction using muscle relaxant only as a rescue medication in case of failure.Patients and methods A randomized controlled study was conducted on 96 patients aged 3–7 years and with American Society of Anesthesiologists physical status I and II scheduled for elective tonsillectomy. Patients were divided randomly into two equal groups, each consisting of 48 patients. Group P patients received inhalational induction using sevoflurane followed by propofol 2 mg/kg. Group L received inhalational induction by sevoflurane followed by topical lidocaine 1% on glottic and supraglottic areas. The intubation conditions, hemodynamic parameters (heart rate, mean blood pressure, and oxygen saturation), respiratory depression, sedation score, and incidence of laryngospasm after recovery were recorded and statistically analyzed.Results The intubation score was statistically significant with a high difference between the two groups. The score mean values were less than 10 with more success of the intubation in the lidocaine group. The success rate of intubation without the use of short-time-acting muscle relaxant was higher in the lidocaine group (88.89%) as compared with the propofol group (79.2%). Hemodynamic stability after intubation in the lidocaine group, was statistically significant. The incidence of postoperative laryngospasm was statistically nonsignificant, but the incidence rate was higher in the propofol group.Conclusion Using lidocaine 1% topically on the larynx can achieve an acceptable condition of the intubation without muscle relaxant in most of the cases, with hemodynamic stability and decreasing incidence of postoperative laryngospasm.

Quantitative Measurement of Adult Human Larynx post General Anesthesia with Intubation.

Introduction: Post-anaesthetic sore throat (PAST) is a well-recognized consequence of tracheal intubation; however, quantitative morphometric measurements remain challenging. This study aimed to introduce a special laser projection device that can facilitate computer-assisted, digitalized analysis and provide important information on laryngeal mucosa change, pre and post-surgery under general anesthesia with intubation.Materials and methods: The laryngeal images were captured and divided into the control group and the intubation group. Image processing techniques were used to quantify the post-extubation laryngeal variation, with its distinct color space and texture features. Meanwhile, the maximum length of the vocal fold, vocal width at the midpoint, and maximum cross-sectional area of the glottic space were determined and calculated. These parameters were analyzed and compared pre and post-surgery.Results: A total of 69 subjects were enrolled in this study, comprising 32 subjects in the healthy group and 37 subjects in the intubation group. The color space and texture analysis with contrast and correlation profiles all shows trend toward higher measures in the intubation group than in the healthy group, with statistical significance and outstanding discrimination ability, especially in the interarytenoid region. The incidence of PAST was approximately 46% (17 patients). The gender difference, type of surgery, and the fixation position of the tube were not significantly related to the PAST occurrence. All the eigenvalues showed significant differences pre and post-surgery in the interarytenoid region and a significant trend toward red and increased contrast texture profiles was revealed. Furthermore, the glottic area showed a significant decrease of 25.29%, while the vocal width showed a significant increase post extubation.Conclusion: Our equipment and processing can measure subtle laryngeal changes that would allow a clinician to diagnose postoperative laryngeal inflammation in a simpler and less invasive way. The trend toward red, the increased contrast texture and vocal width, and the reduced glottic space were all compatible with post-intubation inflammatory response, especially in the interarytenoid region. This is important to know so that one can take appropriate steps to alleviate PAST in the future.

Quantitative assessment of progressive laryngeal hemiplegia in a 4-year-old beagle.

Progression of unilateral laryngeal paralysis (LP) was quantified in an asymptomatic 4-year-old beagle during spontaneous breathing stimulated with inhaled 10% CO2. Laryngeal evaluation was performed sequentially to track progression of LP over an 18-month period. Videos of the larynx during CO2-stimulated breathing were obtained under propofol anaesthesia. Maximal inspiratory normalised glottal gap area (NGGA) was determined on each occasion for left and right hemiglottis. Left NGGA was smaller than the right side throughout the period of follow-up. After 18 months, LP had progressed to such a degree that the left arytenoid was completely paralysed with no movement during inspiration. This case report demonstrates the possibility of early detection of LP, and quantification of progression. Early detection may allow regenerative surgical strategies for LP to maintain glottic area and reduce postoperative complication rates.

Objective Laryngoscopic Measures From Older Patients With Voice Complaints and Signs of Aging.

The purpose of this study was to use objective measures of glottal gap, bowing, and supraglottic compression from selected images of laryngoscopic examinations from adults over 60 years of age with voice complaints and signs of aging to test current hypotheses on whether degree of severity impacts treatment recommendations and potential follow-through with treatment. Records from 108 individuals 60 years or older with voice complaints and signs of aging were reviewed. Three objective measures (normalized glottal gap area [NGGA], total bowing index, and normalized true vocal fold width) were derived. Each measure was subsequently divided into three categories by severity: absence, small degree, or large degree. Nonparametric statistics tested associations between severity and treatment recommendations as well as potential follow-through. Noninvasive treatments (observation/voice therapy) were marginally associated with no glottal gap (p = .09). More invasive treatments (injection/bilateral thyroplasty) were associated with glottal gaps being present (p = .026), but bilateral thyroplasty recommendations were not significantly associated with the largest gaps. Treatment modalities were not characterized by specific severity categories for any of the objective measures. No significant differences were found for any of the three objective measures between those who followed through with recommended treatment and those who did not. Results demonstrated some support for current hypotheses on how degrees of severity of objective measures relate to treatment recommendations. Of the three measures, NGGA appears to be more informative regarding treatment recommendations and follow-through, but due to low power, larger sample sizes are needed to confirm clinical relevance.

Radiological correlates of vocal fold bowing as markers of Parkinson's disease progression: A cross-sectional study utilizing dynamic laryngeal CT.

To determine whether arytenoid cartilage position and dynamics change with advancing duration and severity (as graded by MDS-UPDRS part III scores) in Parkinson's disease, in a cross-sectional study design, we performed laryngeal four-dimensional computed tomography (4D-CT) in people with Parkinson's disease and controls. 31 people with Parkinson's disease covering a range of disease duration and severity and 19 controls underwent laryngeal 4D-CT whilst repeatedly vocalizing. We measured on each CT volume the glottic area (GA), inter-arytenoid distance (IAD), IAD-Area index (IAI) and arytenoid cartilage velocity ([Formula: see text]). People with Parkinson's disease had reductions in the mean/effective minimum IAD when compared to controls, while mean/effective minimum GA and mean/effective maximum IAI were increased. Arytenoid cartilage velocities showed no difference. On Spearman correlation analyses, advancing disease duration and severity of PD showed moderately strong and significant correlations with increasing mean/effective minimum GA, increasing mean/effective maximum IAI and decreasing effective minimum IAD. Linear mixed models which considered the effects of intra and inter-individual variation showed that both disease duration (b = -0.011, SEb = 0.053, 95% CI [-0.022, 0], t(27) = -2.10, p = 0.045) and severity (b = -0.069, SEb = 0.032, 95% CI [-0.14,-0.0039], t(27) = -2.17, p = 0.039) were significant predictors for IAD, and also for transformed values of the GA and IAI. There are progressive alterations in phonatory posturing as Parkinson's disease advances. The increases in GA despite reductions in IAD are concordant with prior observations of vocal fold bowing. Our study provides a basis for using laryngeal 4D-CT to assess disease progression in Parkinson's disease.

Videolaryngoscopy vs. Direct Laryngoscopy for Elective Airway Management in Paediatric Anaesthesia: A prospective randomised controlled trial.

The indirect visualisation of the glottic area with a videolaryngoscope could improve intubation conditions which may possibly lead to a higher success rate of the first intubation attempt. Comparison of videolaryngoscopy and direct laryngoscopy for elective airway management in paediatric patients. Prospective randomised controlled trial. Operating room. 535 paediatric patients undergoing elective anaesthesia with tracheal intubation. 501 patients were included in the final analysis. Patients were randomly allocated to the videolaryngoscopy group (n = 265) and to the direct laryngoscopy group (n = 269) for the primary airway management. The first attempt intubation success rate was assessed as the primary outcome. The secondary outcomes were defined as: the time to successful intubation (time to the first EtCO2 wave), the overall intubation success rate, the number of intubation attempts, the incidence of complications, and the impact of the length of the operator's clinical practice. The study was terminated after the planned interim analysis for futility. There were no significant demographic differences between the two groups. The first attempt intubation success rate was lower in the videolaryngoscopy group; 86.8% (n = 211) vs. 92.6% (n = 239), P = 0.046. The mean time to the first EtCO2 wave was longer in the videolaryngoscopy group at 39.0 s ± 36.7 compared to the direct laryngoscopy group, 23.6 s ± 24.7 (P < 0.001). There was no difference in the overall intubation success rate, in the incidence of complications nor significant difference based on the length of the clinical practice of the operator. The first attempt intubation success rate was lower in the videolaryngoscopy group in comparison to the direct laryngoscopy group. The time needed for successful intubation with videolaryngoscopy was longer compared with direct laryngoscopy. Clinicaltrials.gov identifier: NCT03747250.

Automatic glottis segmentation for laryngeal endoscopic images based on U-Net

The glottis’s morphology not only reflects vocal and respiratory information, but also plays an important role in the diagnosis of laryngeal diseases. The glottis segmentation is a primary step in computer-aided diagnostic system, however is challenging due to various shapes of glottis, low contrast with surrounding tissues, the existence of laryngeal diseases and so on. In this paper, a deep attention network based on U-Net with color normalization operation (CN-DA-Unet) is proposed to achieve an end-to-end segmentation of the glottal area for the first time. The original images are first processed by color normalization to reduce the adverse effects of low contrast and large differences in colors between different images. The normalized images are then sent to the proposed DA-Unet for feature extraction. In this network, residual structure is incorporated to extract rich features from deep neural networks. After extracting features, a feature pyramid attention (FPA) module is applied to enhance the semantic information of the glottal area. These features are up-sampled and added to the features from the corresponding encoding layer for several times to obtain the final segmented image. The proposed approach is tested on laryngeal images of an in–house dataset including images from healthy subjects and pathologic subjects. Its performance is evaluated by several reliable and popular evaluation metrics, achieving the dice coefficient of 92.9%, sensitivity of 93.5% and precision of 92.6%. These results demonstrate the effectiveness of our proposed approach and the better performance comparing with several popular networks.

Influence of doxapram and intermittent 10% carbon dioxide inspiration on cardiovascular and laryngeal functions in anesthetized dogs.

To compare the effects of two doses of doxapram intravenous injection and carbon dioxide inhalation on the cardiovascular and laryngeal functions of anesthetized hounds. Experimental study. Six healthy adult dogs. In a Latin-square design, the mean arterial blood pressure (MABP) and heart rate (HR) were recorded continuously. The inspiratory normalized glottic gap areas (iNGGA) were measured before and after each stimulation with 0.55 mg/kg of doxapram (L-DOX), 2.2mg/kg of doxapram (H-DOX), or 90 s of inhalation of 10% carbon dioxide in oxygen (I-CO2 ). The stimulations were tested in duplicate or triplicate. Video clips of the laryngeal movement were scored by board-certified surgeons masked to the treatment. The MABP increased with L-DOX and H-DOX up to 81% (both p < .001 compared to I-CO2 ), and persisted during the other stimulations (both p < .001). An intermittent tachycardic effect of up to 79% increase in HR was observed with doxapram. The HR following H-DOX was higher than L-DOX and I-CO2 (both p < .016). Neither hypertension nor tachycardia was observed with I-CO2 . The iNGGA increased with all treatments (p < .001). The iNGGA was greater with H-DOX than L-DOX and I-CO2 (both p < .007). All treatments received higher scores (all p < .001) with acceptable inter- and intra-observers Krippendorff's alphas. All treatments were effective respiratory stimulants in anesthetized dogs; however, doxapram caused hypertension and tachycardia. Carbon dioxide inhalation might improve arytenoid motion without cardiovascular effects in dogs during clinical airway examinations.

Influence of Reduced Saliva Production on Phonation in Patients With Ectodermal Dysplasia

Patients with ectodermal dysplasia (ED) suffer from an inherited disorder in the development of the ectodermal structures. Besides the main symptoms, i.e. significantly reduced formation/expression of teeth, hair and sweat glands, a decreased saliva production is objectively accounted. In addition to difficulties with chewing/swallowing, ED patients frequently report on the subjective impression of rough and hoarse voices. A correlation between the reduced production of saliva and an affliction of the voice has not yet been investigated objectively for this rare disease. Following an established measurement protocol, a study has been conducted on 31 patients with ED and 47 controls (no ED, healthy voice). Additionally, the vocal fold oscillations were recorded by high-speed videoendoscopy (HSV@4kHz). The glottal area waveform was determined by segmentation and objective glottal dynamic parameters were calculated. The generated acoustic signal was evaluated by objective and subjective measures. The individual impairment was documented by a standardized questionnaire (VHI). Additionally, the amount of generated saliva was measured for a defined period of time. ED patients displayed a significantly reduced saliva production compared to the control group. Furthermore, the auditory-perceptual evaluation yielded significantly higher ratings for breathiness and hoarseness in the voices of male ED patients compared to male controls. The majority of male ED patients (67%) indicated at least minor impairment in the self-evaluation. Objective acoustic measures like Jitter and Shimmer confirmed the decreased acoustic quality in male ED patients, whereas none of the investigated HSV parameters showed significant differences between the test groups. Statistical analysis did not confirm a statistically significant correlation between reduced voice quality and amount of saliva. An objective impairment of the acoustic outcome was demonstrated for male ED patients. However, the vocal folds dynamics in HSV recordings seem unaffected.

Numerical solution of Rothenberg's equation of the glottal airflow rate as a function of the glottal area using backward differentiation (L).

This letter shows the application of backward differentiation formulas to solve a differential equation by Rothenberg [(1981). Department for Speech, Music and Hearing Quarterly Progress and Status Report (KTH Royal Institute of Technology, Stockholm, Sweden), Vol. 22], which models the glottal airflow rate vs the glottal area. The formulas avoid a singularity of the equation that occurs when the glottal area is zero and that prevents the application of Runge-Kutta and other numerical methods. They can also be used when the equation is augmented with a glottal air viscosity term to eliminate non-differentiability at glottal opening and closure.

Risk factors of laryngeal injuries in extubated critical pediatric patients

BackgroundThe larynx in children is unique compared to adults. This makes the larynx more prone to trauma during intubation. Under sedation and frequent repositioning of the tube are recorded as risk factors for laryngeal injury. We examined the larynx of 40 critically ill children in the first 24 h after extubation to estimate the frequency and analyze the risk factors for laryngeal trauma using the classification system for acute laryngeal injury (CALI).ResultsThe post-extubation stridor patients had a higher frequency of diagnosis of inborn errors of metabolism, longer duration of ventilation, longer hospital stay, moderate to severe involvement of glottic and subglottic area, frequent intubation attempts, and more than 60 s to intubate Regression analysis of the risk factors of severity of the injury has shown that development of ventilator-associated pneumonia carried the highest risk (OR 32.111 95% CI 5.660 to 182.176), followed by time elapsed till intubation in seconds (OR 11.836, 95% CI 2.889 to 48.490), number of intubation attempts (OR 10.8, CI 2.433 to 47.847), and development of pneumothorax (OR 10.231, 95% CI 1.12 to 93.3).ConclusionThe incidence of intubation-related laryngeal trauma in pediatric ICU is high and varies widely from mild, non-symptomatic to moderate, and severe and could be predicted by any of the following: prolonged days of ventilation, pneumothorax, multiple tube changes, or difficult intubation.

Multivariate Analysis of Vocal Fold Vibrations on Various Voice Disorders Using High-Speed Digital Imaging

Although many quantitative parameters have been devised to describe abnormalities in vocal fold vibration, little is known about the priority of these parameters. We conducted a prospective study using high-speed digital imaging to elucidate disease-specific key parameters (KPs) to characterize the vocal fold vibrations of individual voice disorders. From 304 patients with various voice disorders and 46 normal speakers, high-speed digital imaging of a sustained phonation at a comfortable pitch and loudness was recorded and parameters from visual-perceptual rating, laryngotopography, digital kymography, and glottal area waveform were calculated. Multivariate analysis was then applied to these parameters to elucidate the KPs to explain each voice disorder in comparison to normal subjects. Four key parameters were statistically significant for all laryngeal diseases. However, the coefficient of determination (R2) was very low (0.29). Vocal fold paralysis (8 KPs, R2 = 0.76), sulcus vocalis (4 KPs, R2 = 0.74), vocal fold scarring (1 KP, R2 = 0.68), vocal fold atrophy (6 KPs, R2 = 0.53), and laryngeal cancer (1 KP, R2 = 0.52) showed moderate-to-high R2 values. The results identified different KPs for each voice disorder; thus, disease-specific analysis is a reasonable approach.

OpenHSV: an open platform for laryngeal high-speed videoendoscopy

High-speed videoendoscopy is an important tool to study laryngeal dynamics, to quantify vocal fold oscillations, to diagnose voice impairments at laryngeal level and to monitor treatment progress. However, there is a significant lack of an open source, expandable research tool that features latest hardware and data analysis. In this work, we propose an open research platform termed OpenHSV that is based on state-of-the-art, commercially available equipment and features a fully automatic data analysis pipeline. A publicly available, user-friendly graphical user interface implemented in Python is used to interface the hardware. Video and audio data are recorded in synchrony and are subsequently fully automatically analyzed. Video segmentation of the glottal area is performed using efficient deep neural networks to derive glottal area waveform and glottal midline. Established quantitative, clinically relevant video and audio parameters were implemented and computed. In a preliminary clinical study, we recorded video and audio data from 28 healthy subjects. Analyzing these data in terms of image quality and derived quantitative parameters, we show the applicability, performance and usefulness of OpenHSV. Therefore, OpenHSV provides a valid, standardized access to high-speed videoendoscopy data acquisition and analysis for voice scientists, highlighting its use as a valuable research tool in understanding voice physiology. We envision that OpenHSV serves as basis for the next generation of clinical HSV systems.