Measurement of the lengths of different sections of the upper airway and their predictive factors.

BACKGROUND: No studies have been conducted to define the lengths of the upper airway's different segments in normal healthy adults. AIMS/OBJECTIVES: This study aimed to determine the length of the subglottis and extrathoracic trachea and the factors affecting it. MATERIAL AND METHODS: This was an observational retrospective review study. Included 102 adult patients who underwent CT scan during the quiet inspiration phase of the upper airway. RESULTS: The results revealed significant positive linear relationships between height and both anterior and posterior subglottic measurements (p < 0.001). Additionally, a statistically significant, moderately strong negative correlation between age and extrathoracic tracheal measurements (p > 0.001) was observed. Men exhibited longer anterior (p < 0.001) and posterior (p > 0.001) subglottic measurements. In both sexes, the average length of the anterior subglottis was 14.16 (standard deviation [SD]: 2.72) mm, posterior subglottis was 14.51 (SD: 2.85) mm and extrathoracic trachea was 66.37 (SD: 13.71) mm. CONCLUSION AND SIGNIFICANCE: We concluded that a normal healthy adult's anterior subglottis length is 6.3-19.3 mm (mean: 14.16 [SD: 2.72] mm), posterior subglottis length is 6.1-20.0 mm (mean: 14.51 [SD: 2.85] mm) and extrathoracic trachea length is 25.2-98.5 mm (mean: 66.37 [SD: 13.71] mm). Age, height and sex affected the upper airway length.

The Effects of a Shoulder Roll During Laryngoscopy in Infants: A Randomized, Single-Blinded, Crossover Study.

BACKGROUND: The use of a shoulder roll to view the glottic opening during direct laryngoscopy in infants has been recommended but is not evidence based. METHODS: Twenty infants with normal airways, <6 months of age undergoing elective surgery under general anesthesia were randomized to undergo direct laryngoscopy first with a 2-inch vertical shoulder roll and then without, or vice versa. The primary outcome was the difference in the vertical distance between the angle of the laryngoscopist's eye and the operating room table in the 2 positions. Also, the views of the glottic opening in both positions were recorded for each infant and analyzed by a blinded investigator using the percent of glottic opening (POGO). RESULTS: Twenty infants completed the study without complications. The vertical distance did not differ significantly whether the shoulder roll was placed first or second, and there was no evidence of a differential carryover effect in the crossover design (P = .268). The main effect of the shoulder roll on the mean (95% confidence interval [CI]) vertical distances without 47.8 cm (43.5-52.1) and with the shoulder roll 37.2 cm (33.3-41) yielded a mean (95% CI) vertical difference of 10.6 cm (9.3-11.79; P = .0001). The median (interquartile range [IQR]) POGO scores without 100 [86.2, 100] and with the shoulder roll 97.5 [80, 100] did not differ (median difference [95% CI]: 0 [-20 to 0]; P = .39). CONCLUSIONS: A 2-inch shoulder roll lowers the line of sight of the glottic opening compared with no shoulder roll, without affecting the view of the glottic opening during laryngoscopy in infants.

Effect of an aerosol box on tracheal intubation difficulty.

The aim of this study was to determine the effect of an aerosol box on tracheal intubation difficulty. Eighteen experienced anesthetists intubated the trachea of a manikin with a normal airway 6 times using a direct laryngoscope, a McGRATH™ MAC videolaryngoscope, or an airway scope AWS-S200NK videolaryngoscope with or without an aerosol box. Although the aerosol box prolonged the time to successful intubation and decreased the percentage of glottic opening (POGO) score when using a direct laryngoscope, the statistically significant differences were clinically irrelevant. When a McGRATH™ MAC and an AWS-S200NK were used, the times to successful intubation and POGO scores were comparable with and without the aerosol box. When using any of the laryngoscopes, there were no statistically significant differences in the Cormack-Lehane grade and peak force to maxillary incisors with and without the aerosol box. In summary, the effect of an aerosol box on tracheal intubation difficulty is not clinically relevant when an experienced anesthetist intubates the trachea in a normal airway condition.

The phylogenetic significance of the morphology of the syrinx, hyoid and larynx, of the southern cassowary, Casuarius casuarius (Aves, Palaeognathae).

BACKGROUND: Palaeognathae is a basal clade within Aves and include the large and flightless ratites and the smaller, volant tinamous. Although much research has been conducted on various aspects of palaeognath morphology, ecology, and evolutionary history, there are still areas which require investigation. This study aimed to fill gaps in our knowledge of the Southern Cassowary, Casuarius casuarius, for which information on the skeletal systems of the syrinx, hyoid and larynx is lacking - despite these structures having been recognised as performing key functional roles associated with vocalisation, respiration and feeding. Previous research into the syrinx and hyoid have also indicated these structures to be valuable for determining evolutionary relationships among neognath taxa, and thus suggest they would also be informative for palaeognath phylogenetic analyses, which still exhibits strong conflict between morphological and molecular trees. RESULTS: The morphology of the syrinx, hyoid and larynx of C. casuarius is described from CT scans. The syrinx is of the simple tracheo-bronchial syrinx type, lacking specialised elements such as the pessulus; the hyoid is relatively short with longer ceratobranchials compared to epibranchials; and the larynx is comprised of entirely cartilaginous, standard avian anatomical elements including a concave, basin-like cricoid and fused cricoid wings. As in the larynx, both the syrinx and hyoid lack ossification and all three structures were most similar to Dromaius. We documented substantial variation across palaeognaths in the skeletal character states of the syrinx, hyoid, and larynx, using both the literature and novel observations (e.g. of C. casuarius). Notably, new synapomorphies linking Dinornithiformes and Tinamidae are identified, consistent with the molecular evidence for this clade. These shared morphological character traits include the ossification of the cricoid and arytenoid cartilages, and an additional cranial character, the articulation between the maxillary process of the nasal and the maxilla. CONCLUSION: Syrinx, hyoid and larynx characters of palaeognaths display greater concordance with molecular trees than do other morphological traits. These structures might therefore be less prone to homoplasy related to flightlessness and gigantism, compared to typical morphological traits emphasised in previous phylogenetic studies.

The distance between the glottis and the cuff of a tracheal tube placed through three supraglottic airway devices in children: A randomised controlled trial.

BACKGROUND: After tracheal tube insertion via various types of supraglottic airway devices, the distance from the tube cuff to the vocal cords has not been evaluated in children. OBJECTIVES: The aim of this study was to evaluate the position of a tracheal tube cuff relative to the glottis in children when one of three supraglottic airway devices (I-gel, AuraGain and air-Q laryngeal airway) are used as intubation conduits. DESIGN: A randomised controlled trial. SETTING: Tertiary children's hospital. PATIENTS: Children aged less than 7 years. INTERVENTION: In vivo fibre-optic assessment and in vitro measurement. MAIN OUTCOME MEASURES: The main outcome was the safety margin: the distance between the ventilation outlet of the supraglottic airway device and the beginning of the proximal cuff minus that from the ventilation outlet to the glottis. The maximum inner diameter of the cuffed tracheal tube that could be inserted, the fibre-optic view score and the oropharyngeal leak pressure were also evaluated. RESULTS: The three devices exhibited significant differences in the distance from the ventilation outlet to the glottis (mean ±â€ŠSD): I-gel 3.6 ±â€Š0.6 cm, AuraGain 3.8 ±â€Š0.7 cm, air-Q 2.8 ±â€Š1.0 cm (P < 0.001). The safety margin was greatest with the air-Q and narrowest with the I-gel: I gel 1.9 ±â€Š1.1 cm, AuraGain 4.4 ±â€Š0.7 cm and air-Q 7.9 ±â€Š1.1 cm. Using the AuraGain and air-Q, the cuffs of the tracheal tubes were predicted to be located below the glottis with one-size and two-size smaller tracheal tubes in all patients. However, using I-gel, the cuffs would be below the glottis in 69% (95% CI 49.6 to 84.5) and 29% (95% CI 14.0 to 48.4) of the patients with a one-size and two-size smaller tube, respectively. CONCLUSION: The AuraGain and air-Q are well tolerated intubating conduits. The possibility of vocal cord damage is higher when the I-gel is used. TRIAL REGISTRATION: www.clinicaltrials.gov (number: NCT03156166).

Effect of changes in medial surface shape on voice production in excised human larynges.

Clinical intervention of glottal insufficiency often focuses on correcting glottal gap as visualized from above. In contrast, changes in medial surface shape due to intervention have received less attention. This study investigated how changes in medial surface shape affect voice production in excised human larynges, by locally medializing the medial surface at different longitudinal and vertical locations. The results showed that localized medialization at a more inferior location yielded better improvement in glottal closure and higher-order harmonic excitation in the produced voice. This study shows that surgical intervention of glottal insufficiency should also aim at restoring desirable medial surface shape.

Tube tip and cuff position using different strategies for placement of currently available paediatric tracheal tubes.

BACKGROUND: Tracheal tube tip and cuff positions of different cuffed paediatric tracheal tube brands in the trachea can vary with design. METHODS: Data from three clinical studies with measured tracheal lengths were pooled in a database including 422 children aged from birth to 16 yr. Dimensional data of seven cuffed paediatric tracheal tube brands (ID 3.0-7.0 mm) were recorded. Positions of tracheal tube tip and upper cuff border were calculated for each of the 422 tracheas using depth mark based tracheal tube placement, placement of the tracheal tube tip at a calculated safety distance above the carina, and mid-tracheal tube placement. Percentage of accidental bronchial intubations and tracheal tube cuff positions in the subglottic or supraglottic region were calculated. RESULTS: Depth mark based tracheal tube placement resulted in accidental bronchial intubation of up to 18% of cases and tracheal tube cuffs being placed in the subglottic region in up to 91%. Tracheal tube tip placement at a calculated safety distance resulted in up to 54% of tube cuffs placed too high. Mid-tracheal tube placement led to 100% subglottic or supraglottic tracheal tube cuff positions. CONCLUSIONS: All studied cuffed paediatric tracheal tubes have major design flaws potentially leading to airway complications. Tracheal tube manufacturers are urgently asked to improve the design of cuffed paediatric tracheal tubes. Alternative strategies for tracheal tube placement can allow safe tracheal tube placement of uncuffed but not of cuffed tracheal tubes.

A randomised clinical trial comparing the 'sniffing' and neutral position using channelled (KingVision® ) and non-channelled (C-MAC® ) videolaryngoscopes.

Head and neck position is one of the factors which can be associated with difficult videolaryngoscopy and tracheal intubation. This prospective randomised clinical trial compared 'sniffing' and neutral positions using a channelled (KingVision® ) and a non-channelled (C-MAC® D-blade) videolaryngoscope in 200 adult patients randomly allocated into four groups (KingVision 'sniffing', KingVision neutral, C-MAC 'sniffing' and C-MAC neutral). The primary outcome was the ease of tracheal intubation using the modified intubation difficulty scale (mIDS) score. Laryngoscopy time, intubation time, laryngoscopic view using the percentage of glottic opening (POGO) score and success rate of tracheal intubation were secondary outcomes. The median (IQR [range]) modified difficulty scale scores for the four groups, respectively, were 0 (0-1 [0-3]), 0 (0-1 [0-4]), 1 (0-1 [0-5]) and 0 (0-1 [0-3]; p = 0.384). There was no significant difference in laryngoscopy time (p = 0.020), intubation time (p = 0.272) and success rate (p = 0.968) between the groups. The percentage of glottic opening score was lower for C-MAC neutral group as compared with other three groups (p = 0.01). There was no significant difference in the ease of intubation between the 'sniffing' and the neutral position when using the KingVision and the C-MAC videolaryngoscopes. Therefore, either of the two positions could be used with these types of videolaryngoscopes, if deemed advantageous for the patient.

An assessment of the tolerability of the Cook staged extubation wire in patients with known or suspected difficult airways extubated in intensive care.

The Cook staged extubation set (Cook Medical) has been developed to facilitate management of the difficult airway. A guidewire inserted before tracheal extubation provides access to the subglottic airway should re-intubation be required. This prospective cohort study examines patients' tolerance of the guidewire and its impact on clinical status around tracheal extubation in the intensive care unit. Vital signs, incidence of symptoms and patient tolerance of the wire were recorded. Twenty-three patients were enrolled and 17 (73%) tolerated the wire for 4 h. Nasendoscopy was performed in 11 of these patients and revealed one wire was in the oesophagus. The most common symptom was a mild intermittent cough in 13 patients. There was no impact of the guidewire on nursing care in 16 patients, tolerable impact in five and severe impact necessitating removal of the wire in one patient.

Effect of the Macintosh curved blade size on direct laryngoscopic view in edentulous patients.

OBJECTIVE: In the present study, we compared the laryngoscopic view depending on the size of the Macintosh curved blade in edentulous patients. METHODS: Thirty-five edentulous adult patients scheduled for elective surgery were included in the study. After induction of anesthesia, two direct laryngoscopies were performed alternately using a standard-sized Macintosh curved blade (No. 4 for men and No. 3 for women) and smaller-sized Macintosh curved blade (No. 3 for men and No. 2 for women). During direct laryngoscopy with each blade, two digital photographs of the lateral view were taken when the blade tip was placed in the valleculae; the laryngoscope was lifted to achieve the best laryngeal view. Then, the best laryngeal views were assessed using the percentage of glottic opening (POGO) score. On the photographs of the lateral view of direct laryngoscopy, the angles between the line extending along the laryngoscopic handle and the horizontal line were measured. RESULTS: The POGO score was improved with the smaller-sized blade compared with the standard-sized blade (87.3% [11.8%] vs. 71.3% [20.0%], P<0.001, respectively). The angles between the laryngoscopic handle and the horizontal line were greater with the smaller-sized blade compared to the standard-sized blade when the blade tip was placed on the valleculae and when the laryngoscope was lifted to achieve the best laryngeal view (both P<0.001). CONCLUSIONS: Compared to a standard-sized Macintosh blade, a smaller-sized Macintosh curved blade improved the laryngeal exposure in edentulous patients.

Simultaneous electromagnetic articulography and electroglottography data acquisition of natural speech.

This paper reports on the concurrent use of electroglottography (EGG) and electromagnetic articulography (EMA) in the acquisition of EMA trajectory data for running speech. Static and dynamic intersensor distances, standard deviations, and coefficients of variation associated with inter-sample distances were compared in two conditions: with and without EGG present. Results indicate that measurement discrepancies between the two conditions are within the EMA system's measurement uncertainty. Therefore, potential electromagnetic interference from EGG does not seem to cause differences of practical importance on EMA trajectory behaviors, suggesting that simultaneous EMA and EGG data acquisition is a viable laboratory procedure for speech research.

Importance of glottis landmarks for the assessment of cleft lip and palate speech intelligibility.

The present work explores the acoustic characteristics of articulatory deviations near g(lottis) landmarks to derive the correlates of cleft lip and palate speech intelligibility. The speech region around the g landmark is used to compute two different acoustic features, namely, two-dimensional discrete cosine transform based joint spectro-temporal features, and Mel-frequency cepstral coefficients. Sentence-specific acoustic models are built using these features extracted from the normal speakers' group. The mean log-likelihood score for each test utterance is computed and tested as the acoustic correlates of intelligibility. Derived intelligibility measure shows significant correlation (ρ = 0.78, p < 0.001) with the perceptual ratings.

The Mechanism and Representation of Korean Three-Way Phonation Contrast: External Photoglottography, Intra-Oral Air Pressure, Airflow, and Acoustic Data.

This paper aims to refine our understanding of the speech mechanism and laryngeal features involved in the Korean lenis (/p t k/), aspirated (/ph th kh/), and fortis (/p' t' k'/) plosives. For this purpose we made measurements using a new noninvasive technique called external lighting and sensing photoglottography (ePGG) as well as intra-oral air pressure (Pio) above the glottis, airflow, and acoustic data. From simultaneous recordings of the experimental data, we were ableto quantify the laryngeal-oral coordination of glottal opening and a consonant release, and the covariance of airflow peak and duration of aspiration with glottal opening. The phasing of glottal opening and the 3-way phonation contrast occurs in the order, from early to late, fortis, lenis < aspirated plosives, and the glottal opening peak ranges from low to high in the same order. We also found that a Pio peak, the durations of a high Pio plateau and an oral closure, and F0 are independent of the glottal opening mechanism, varying in the order lenis < aspirated and fortis plosives. From these findings, we propose that the 2 independent patterns are accounted for by the articulator-based features [±spread glottis] and [±tense], respectively.

Randomized equivalence trial of the King Vision aBlade videolaryngoscope with the Miller direct laryngoscope for routine tracheal intubation in children <2 yr of age.

BACKGROUND.: We conducted a randomized equivalence trial to compare direct laryngoscopy using a Miller blade (DL) with the King Vision videolaryngoscope (KVL) for routine tracheal intubation. We hypothesized that tracheal intubation times with DL would be equivalent to the KVL in children <2 yr of age. METHODS.: Two hundred children were randomly assigned to tracheal intubation using DL or KVL. The primary outcome was the median difference in the total time for successful tracheal intubation. Secondary outcomes assessed were tracheal intubation attempts, time to best glottic view, time for tracheal tube entry, percentage of glottic opening score, airway manoeuvres needed, and complications. RESULTS.: The median difference between the groups was 5.7 s, with an upper 95% confidence interval of 7.5 s, which was less than our defined equivalence time difference of 10 s. There were no differences in the number of tracheal intubation attempts and the time to best glottic view [DL median 5.3 (4.1-7.6) s vs KVL 5.0 (4.0-6.3) s; P =0.19]. The percentage of glottic opening score was better when using the KVL [median 100 (100-100) vs DL median 100 (90-100); P <0.0001]. Use of DL was associated with greater need for airway manoeuvres during tracheal intubation (33 vs 7%; P <0.001). Complications did not differ between devices. CONCLUSIONS.: In children <2 yr of age, the KVL was associated with equivalent times for routine tracheal intubation when compared with the Miller blade. CLINICAL TRIAL REGISTRATION: NCT02590237.

The Cricoid Force Necessary to Occlude the Esophageal Entrance: Is There a Gender Difference?

BACKGROUND: We tested the hypothesis whether gender differences exist in the applied cricoid force necessary to prevent regurgitation. Real-time visual and dynamic means were used to assess the effectiveness of different applied cricoid forces in occluding the esophageal entrance in men (group 1) and in women (group 2). METHODS: In anesthetized and paralyzed patients, the glottis and esophageal entrance were visualized with a Glidescope video laryngoscope. Trained operators performed cricoid pressure (CP) and gastric tube insertion trials. Successful gastric tube insertion in the presence of CP was considered ineffective CP, whereas unsuccessful insertion was considered effective CP. The applied cricoid forces were measured with a novel instrument, the cricometer. The first patient in each group received 20 N. The applied cricoid force in successive patients was determined by the response of the previous patient within the same group, using the up-and-down sequential allocation technique. RESULTS: In the 30 men and 30 women who qualified for the study, the median cricoid force (cricoid force = 50) that occluded the esophageal entrance was 30.8 N (95% confidence interval = 28.15-33.5) in men, and 18.7 N in women (95% confidence interval = 17.1-20.3; P < .0001). Patency of the esophageal entrance was observed when CP was not applied and when inadequate forces that allowed successful esophageal cannulation were used. CONCLUSIONS: The current study provides evidence that the median force necessary to occlude the esophageal entrance to prevent regurgitation is less in women compared with men. Applying the appropriate cricoid force in women should also decrease airway-related problems that tend to occur with the use of excessive forces. The findings of the current study may only be applicable to patients with normal body habitus.

Ventilation via the 2.4 mm internal diameter Tritube® with cuff - new possibilities in airway management.

BACKGROUND: A small tube may facilitate tracheal intubation and improve surgical access. We describe our initial experience with the Tritube® that is a novel cuffed endotracheal tube with a 2.4 mm internal diameter. METHODS: The Tritube® was used in seven adult Ear-Nose-and Throat surgical patients with airway narrowing or whose surgical access was facilitated by this small-bore endotracheal tube. Ventilation through Tritube® is performed with the manually operated Ventrain® -ventilator that allows active suctioning during expiration, therefore facilitating normoventilation through small diameter airways. RESULTS: The small diameter of Tritube® seemed to improve glottis visualisation during intubations and gave excellent working conditions for surgery. Two patients were intubated awake with a flexible scope and a guide wire or with an angulated video laryngoscope. One patient had almost complete glottic occlusion that just allowed for passage of the Tritube® . Adequate ventilation was achieved in all patients and intratracheal pressure was kept between 5 and 20 cm H2 O. The tube was well tolerated after emergence from anaesthesia and kept intratracheally in five awake patients in the post-operative recovery unit, in one case for more than 1 h. Ventilating with Ventrain® through Tritube® demands meticulous breath by breath measurement and adjustment of the intratracheal pressure. CONCLUSION: The 2.4 mm internal diameter Tritube® seems to facilitate tracheal intubation and to provide unprecedented view of the intubated airway during oral, pharyngeal, laryngeal or tracheal procedures in adults. This technique has the potential to replace temporary tracheostomy, jet-ventilation or extra-corporal membrane oxygenation in selected patients.

Upper airway in infants-a computed tomography-based analysis.

BACKGROUND: Recent studies suggest that the pediatric airway is elliptical with the subglottis rather than the cricoid as the narrowest part contrary to the old belief of a funnel-shaped airway. The shape of the airway in neonates and infants has not been studied separately. This study seeks to define the shape of the upper airway in neonates and infants, and determine if there are differences in airway shape between infants and older children. METHODS: We studied 40 computed tomographic scans of children from birth to 12 months of age undergoing radiological evaluation unrelated to airway symptomatology. The computed tomographic scans were obtained during either natural sleep or with sedation and spontaneous ventilation without airway devices in place. Transverse and anteroposterior diameters were measured at the subglottic level and at the cricoid ring. RESULTS: The mean age was 5.9 ± 3.4 months. The mean transverse and anteroposterior diameters were 5.3 ± 0.83 mm and 7.2 ± 0.89 mm at the subglottic region and 6.1 ± 0.86 mm and 6.7 ± 0.79 mm at the cricoid level. An increase in the transverse dimension of the airway was observed from the subglottic region to the cricoid ring. Although the anteroposterior dimension decreased from the subglottis to the cricoid ring, the airway remained wider in the anteroposterior dimension compared to the transverse dimension from the subglottis to the cricoid ring. CONCLUSION: The present study demonstrates that the airway in neonates and infants between the subglottic area and the cricoid remains elliptical. The cricoid is not round as has been observed in older children. The airway is wider anteroposteriorly and narrows in the transverse dimension from the subglottis to the cricoid in infants.

Pediatric upper airway dimensions using three-dimensional computed tomography imaging.

INTRODUCTION: Computed tomography- (CT) and magnetic resonance imaging (MRI)-based measurements have recently suggested that the narrowest dimension of the pediatric airway is the subglottic region. These data are contrary to the previously held tenets of a funnel- or conical-shaped airway. The current study evaluates airway volumes and shapes using three-dimensional CT images of the air way column in spontaneously breathing children. METHODS: The study included CT-based radiological images of the neck in children who required imaging unrelated to airway symptomatology. The children were evaluated during spontaneous ventilation during natural sleep or with sedation without airway devices in place. The three-dimensional images of the airway column were evaluated, volumes calculated, and comparisons made between the subglottic, cricoid, and tracheal volumes and shapes. RESULTS: The study cohort included 54 children, ranging in age from 2 months to 8 years. An increase in the airway volumes was observed from the subglottic (0.17 ± 0.06 mm3 ) to the cricoid (0.19 ± 0.06 mm3 ) to the tracheal regions (0.22 ± 0.07 mm3 ). The volumes of the subglottic, cricoid, and tracheal regions demonstrated a linear relationship with age. CONCLUSION: This study confirms recent studies demonstrating that the subglottic region not the cricoid is the narrowest part of the airway.

Association of breathing sound spectra with glottal dimensions in exercise-induced vocal cord dysfunction.

The objective of this study was to evaluate associations between the breathing sound spectra and glottal dimensions in exercise-induced vocal cord dysfunction (EIVCD) during a bicycle ergometry test. Nineteen subjects (mean age 21.8 years and range 13-39 years) with suspected EIVCD were studied. Vocal folds were continuously imaged with videolaryngoscopy and breathing sounds were recorded during the bicycle exercise test. Twelve subjects showed paradoxical movement of the vocal folds during inspiration by the end of the exercise. In seven subjects, no abnormal reactions in vocal folds were found; they served as control subjects. The glottal quotient (interarytenoid distance divided by the anteroposterior glottal distance) was calculated. From the same time period, the tracheal-vocal tract resonance peaks of the breathing sound spectra were analyzed, and stridor sounds were detected and measured. Subjects with EIVCD showed significantly higher resonance peaks during the inspiratory phase compared to the expiratory phase (p < 0.014). The glottal quotient decreased significantly in the EIVCD group (p < 0.001), but not in the control group. 8 out of 12 EIVCD patients (67%) showed stridor sounds, while none of the controls did. There was a significant inverse correlation between the frequencies of the breathing sound resonance peaks and the glottal quotient. The findings indicate that the typical EIVCD reaction of a paradoxical approximation of the vocal folds during inspiration, measured here as a decrease in the glottal quotient, is significantly associated with an increase in inspiratory resonance peaks. The findings are applicable in the documentation of EIVCD findings using videolaryngoscopy, in addition to giving clinicians tools for EIVCD recognition. However, the study is limited by the small number of subjects.

Simulating alveolar trills using a two-mass model of the tongue tip.

This paper investigates the possibility of reproducing the self-sustained oscillation of the tongue tip in alveolar trills. The interest is to study the articulatory and phonatory configurations that are required to produce alveolar trills. Using a realistic geometry of the vocal tract, derived from cineMRI data of a real speaker, the paper studies the mechanical behavior of a lumped two-mass model of the tongue tip. Then, the paper proposes a solution to simulate the incomplete occlusion of the vocal tract during linguopalatal contacts by adding a lateral acoustic waveguide. Finally, the simulation framework is used to study the impact of a set of parameters on the characteristic features of the produced alveolar trills. It shows that the production of trills is favored when the distance between the equilibrium position of the tongue tip and the hard palate in the alveolar zone is less than 1 mm, but without linguopalatal contact, and when the glottis is fully adducted.