Laryngeal Closure Research Articles

Intravenous Bolus Injection of Fentanyl Triggers an Immediate Central and Upper Airway Obstructive Apnea via Activating Vagal Sensory Afferents.

Intravenous bolus (IVb) injection of fentanyl induces an immediate apnea, but the characteristics of the apnea and relevant mechanism remain unclear. Here, we tested whether IVb injection of fentanyl induced an immediate central and upper airway obstructive apnea associated with chest wall rigidity via activating vagal C-fibers (VCFs) and vagal afferent opioid receptors (ORs). Cardiorespiratory and electromyography of external and internal intercostal, thyroarytenoid and superior pharyngeal constrictor muscles (EMGEI, EMGII, EMGTA and EMGSPC) responses to IVb injection of fentanyl were recorded in anesthetized and spontaneously breathing rats with or without bilateral peri-vagal capsaicin treatment or intra-vagal microinjection of naloxone. Immunohistochemical approach was employed to define the presence of opioid mu-receptor (MOR) expression in vagal C-neurons and a patch clamp technique utilized to determine the evoked current responses of vagal C-neurons to fentanyl in vitro. Fentanyl induced an immediate apnea and subsequent respiratory depression. The apnea was characterized by cessation of EMGEI activity and augmentation of tonic discharges of EMGII, EMGTA, and EMGSPC, i.e., central expiratory apnea, laryngeal closure and pharyngeal constriction/collapse accompanied with chest wall rigidity. The apneic response was abolished by blockade of VCF signal conduction and largely attenuated by antagonism of vagal afferent ORs. The latter significantly alleviated the initial (within 5 min post injection), but not the later, respiratory depression. Vagal C-neurons expressed MORs and were activated by fentanyl. We conclude that IVb injection of fentanyl causes a VCF- and vagal afferent OR-mediated immediate central apnea, upper airway obstruction and chest wall rigidity.

Predicting Swallowing Recovery in Subacute Stroke Patients via Temporal and Spatial Parameters of Videofluoroscopy.

The purpose of this study was to identify the temporal and spatial parameters of videofluoroscopic swallowing study (VFSS) that could predict the recovery of swallowing function in subacute stroke patients. We included 102 patients who were admitted to the Department of Rehabilitation Medicine between 2019 and 2022. Patients were classified into good and poor prognosis groups according to whether they had restored prestroke swallowing function or were able to consume sufficient nutrition via oral feeding to meet their body's needs. Univariate and multivariate regression analyses were used to identify the predictors. Calibration and discrimination were tested using the Hosmer-Lemeshow test and area under the curve (AUC), respectively. Of the 102 included patients, 51 had a good prognosis for swallowing function within 6 months of onset. The final multivariate regression model included three significant factors: laryngeal closure duration (LCD) (OR: 0.998; 95% CI: 0.996-0.999; p < 0.05), maximum width of the upper esophageal sphincter opening (MWUESO) (OR: 1.251; 95% CI: 1.073-1.458; p < 0.05), and pharyngeal residual grade (PRG) (p < 0.05). The shorter LCD and larger MWUESO were positive predictors of good swallowing function outcomes, while higher PRG was a negative predictor of good outcomes. The AUC for PRG, MWUESO, and LCD were 0.767 (p < 0.05), 0.738 (p < 0.05), and 0.681 (p < 0.05), respectively. Identifying prognostic factors for the recovery of swallowing function in patients with poststroke dysphagia is essential for developing treatment strategies. The findings of this study may provide an important reference for developing appropriate therapeutic interventions to promote the recovery of swallowing function in stroke patients.

Respiratory-swallow patterning and oropharyngeal swallowing impairment in patients undergoing evaluation for lung transplant.

Although swallowing impairment is prevalent following lung transplantation, baseline respiratory and swallowing characteristics are often overlooked. Respiratory disease processes may predispose lung transplant candidates to altered respiratory-swallow patterning and swallowing impairment. This cross-sectional study included patients referred for a Modified Barium Swallow Study during lung transplant evaluation. Swallowing impairment was measured using the Modified Barium Swallow Impairment Profile and Penetration-Aspiration Scale. Respiratory plethysmographic signals synchronized with videofluoroscopy were analyzed to determine phase patterning, pause duration, and rate. Mixed-effects logistic regression was used to identify linkages between respiratory and swallowing measures. Fifty patients were included and demonstrated delayed swallow initiation (49/50), oral residue (37/50), incomplete pharyngoesophageal segment opening (35/50), and esophageal retention (43/50). Airway invasion occurred infrequently (10/50). Atypical respiratory patterning was significantly associated with impairment in pharyngeal swallow initiation (OR [95% CI] = 1.76 [1.16, 2.68], p = 0.009), laryngeal elevation (OR [95% CI] = 1.45 [1.01, 2.07], p = 0.044), and laryngeal vestibular closure (OR [95% CI] = 2.57 [1.48, 4.46], p < 0.001). Increased pause duration was associated with impaired initiation (OR [95% CI] = 2.24 [1.20, 4.16], p = 0.011), laryngeal elevation (OR [95% CI] = 1.18 [1.03, 1.36], p = 0.018), laryngeal closure (OR [95% CI] = 1.28 [1.9, 1.50], p = 0.003), and tongue base retraction (OR [95% CI] = 1.33 [1.13, 1.56], p < 0.001). Patients undergoing evaluation for lung transplant demonstrated impaired swallowing and phase patterning. Preliminary findings implicate the need for further evaluation of respiratory-swallow coordination and its potential role in swallowing impairment before and after lung transplantation.

Upper Airway and Translaryngeal Resistance During Mechanical Insufflation-Exsufflation

Mechanical insufflation-exsufflation (MI-E) uses positive and negative pressures to assist weak cough and help clear airway secretions. Laryngeal visualization during MI-E has revealed that inappropriate upper airway responses can impede its efficacy. However, the dynamics of pressure transmission in the upper airways during MI-E is unclear, as are the relationships between anatomical structure, pressure and airflow. Can airflow resistance through the upper airway and the larynx feasibly be calculated during MI-E, and if so, how are the pressures transmitted to the trachea? Cross-sectional study of ten healthy adults, where MI-E was provided with and without active cough, employing pressure settings +20/-40 and ±40 cmH2O. Airflow and pressure at the level of the facemask were measured using a pneumotachograph, while pressure transducers (positioned via transnasal fiberoptic laryngoscopy) recorded pressures above the larynx and within the trachea. Upper airway resistance (Ruaw) and translaryngeal resistance (Rtl) were calculated (cmH2O/L/sec) and compared to direct observations via laryngoscopy. Positive pressures reached the trachea effectively, while negative tracheal pressures during exsufflation were approximately half of the intended settings. Insufflation pressure increased slightly when passing through the larynx. Participant effort influenced tracheal pressures and the resistances, with findings consistent with laryngoscopic observations. During MI-E, resistance appears dynamic, with Ruaw exceeding Rtl. Inappropriate laryngeal closure increased Rtl during both positive and negative pressures. Upper airway and translaryngeal resistance can feasibly be calculated during MI-E. The findings indicate different transmission dynamics for positive and negative pressures, and that resistances are influenced by participant effort. The findings support using lower insufflation pressures and higher negative pressures in clinical practice.

Application value research of swallowing treatment device combined with swallowing rehabilitation training in the treatment of swallowing disorders after stroke.

Stroke is a common disabling disease, whether it is ischemic stroke or hemorrhagic stroke, both can result in neuronal damage, leading to various manifestations of neurological dysfunction. To explore of the application value of swallowing treatment device combined with swallowing rehabilitation training in the treatment of swallowing disorders after stroke. This study selected 86 patients with swallowing disorders after stroke admitted to our rehabilitation department from February 2022 to December 2023 as research subjects. They were divided into a control group (n = 43) and an observation group (n = 43) according to the treatment. The control group received swallowing rehabilitation training, while the observation group received swallowing treatment device in addition to the training. Both groups underwent continuous intervention for two courses of treatment. The total effective rate in the observation group (93.02%) was higher than that in the control group (76.74%) (P = 0.035). After intervention, the oral transit time, swallowing response time, pharyngeal transit time, and laryngeal closure time decreased in both groups compared to before intervention. In the observation group, the oral transit time, swallowing response time, and pharyngeal transit time were shorter than those in the control group after intervention. However, the laryngeal closure time after intervention in the observation group was compared with that in the control group (P = 0.142). After intervention, average amplitude value and duration of the genioglossus muscle group during empty swallowing and swallowing 5 mL of water are reduced compared to before intervention in both groups. After intervention, the scores of the chin-tuck swallowing exercise and the Standardized Swallowing Assessment are both reduced compared to pre-intervention levels in both groups. However, the observation group scores lower than the control group after intervention. Additionally, the Functional Oral Intake Scale scores of both groups are increased after intervention compared to pre-intervention levels, with the observation group scoring higher than the control group after intervention (P < 0.001). The cumulative incidence of complications in the observation group is 9.30%, which is lower than the 27.91% in the control group (P = 0.027). The combination of swallowing therapy equipment with swallowing rehabilitation training can improve the muscle movement level of the genioglossus muscle group, enhance swallowing function, and prevent the occurrence of swallowing-related complications after stroke.

How Do Quantitative Videofluoroscopy Measures Differ Between People With Amyotrophic Lateral Sclerosis and Age-Matched Healthy Adults?

Dysphagia is a leading cause of morbidity in people with amyotrophic lateral sclerosis (PwALS). Previous videofluoroscopic swallowing studies (VFSS) in PwALS do not account for the influence of senescence. We aimed to compare swallowing in PwALS and an age- and sex-matched control group using healthy reference data to define typical and atypical values. We conducted retrospective analysis of VFSS data from 19 PwALS (10 male, Mage = 63 years, range: 47-82) compared to control data from a cohort of healthy adults. Participants swallowed 20% w/v liquid barium from thin to extremely thick consistency. Blinded duplicate VFSS analysis using the ASPEKT (Analysis of Swallowing Physiology: Events, Kinematics and Timing) method yielded descriptive statistics for 16 quantitative VFSS parameters by consistency. Mann-Whitney U tests were used to identify significant cohort differences. Additionally, the frequencies of atypical values (in the 25% tails of the reference distribution) were tabulated by cohort and compared using odds ratios. PwALS showed increased frequencies of multiple swallows per bolus, incomplete laryngeal vestibule closure, and reduced hyoid speed across consistencies. By contrast, similar frequencies of atypical values for pharyngeal constriction and residue in both cohorts suggest that age-related changes may contribute to the presence of these features in PwALS. This analysis builds on previous descriptions of swallowing pathophysiology in amyotrophic lateral sclerosis (ALS) by clarifying the extent to which aging may account for some of the atypical findings seen in this patient population. Longitudinal studies are recommended to further differentiate the effects of ALS from age-related changes in swallowing over the course of disease progression.

Oropharyngeal swallowing hydrodynamics of thin and mildly thick liquids in an anatomically accurate throat-epiglottis model

Understanding the mechanisms underlying dysphagia is crucial in devising effective, etiology-centered interventions. However, current clinical assessment and treatment of dysphagia are still more symptom-focused due to our limited understanding of the sophisticated symptom-etiology associations causing swallowing disorders. This study aimed to elucidate the mechanisms giving rise to penetration flows into the laryngeal vestibule that results in aspirations with varying symptoms. Methods: Anatomically accurate, transparent throat models were prepared with a 45° down flapped epiglottis to simulate the instant of laryngeal closure during swallowing. Fluid bolus dynamics were visualized with fluorescent dye from lateral, rear, front, and endoscopic directions to capture key hydrodynamic features leading to aspiration. Three influencing factors, fluid consistency, liquid dispensing site, and dispensing speed, were systemically evaluated on their roles in liquid aspirations. Results: Three aspiration mechanisms were identified, with liquid bolus entering the airway through (a) the interarytenoid notch (notch overflow), (b) cuneiform tubercle recesses (recess overflow), and (c) off-edge flow underneath the epiglottis (off-edge capillary flow). Of the three factors considered, liquid viscosity has the most significant impact on aspiration rate, followed by the liquid dispensing site and the dispensing speed. Water had one order of magnitude higher aspiration risks than 1% w/v methyl cellulose solution, a mildly thick liquid. Anterior dispensing had higher chances for aspiration than posterior oropharyngeal dispensing for both liquids and dispensing speeds considered. The effects of dispending speed varied. A lower speed increased aspiration for anterior-dispensed liquids due to increased off-edge capillary flows, while it significantly reduced aspiration for posterior-dispensed liquids due to reduced notch overflows. Visualizing swallowing hydrodynamics from multiple orientations facilitates detailed site-specific inspections of aspiration mechanisms.

Effortful Swallow Maneuver and Modifications on Swallow Dynamics in Healthy Adults

Introduction: Effortful swallow (ES) is a widely used technique in dysphagia management, believed to strengthen oropharyngeal muscles and enhance swallowing safety and efficiency. Although its impact on the oral phase of swallowing is well documented, its effects on pharyngeal swallowing physiology remain inconsistent. This study aimed to elucidate the effects of ES on swallowing kinematics and timing, addressing existing inconsistencies in the literature. Methods: This study involved 22 healthy adults using archived videofluoroscopic swallowing studies. Participants performed three swallow trials of 10 mL puree under regular conditions and with the ES maneuver. The outcome measures comprised swallow timing and kinematic measures. Swallow timing parameters included time to maximum hyoid and laryngeal excursion, laryngeal vestibule closure (LVC) reaction and duration, pharyngeal constriction duration, pharyngoesophageal segment (PES) opening duration, and swallow duration. Swallow kinematic parameters encompassed hyoid and laryngeal excursions, pharyngeal constriction ratio, and maximum PES width. All variables were analyzed via videofluoroscopy. Paired t tests were used to examine the effect of ES on each outcome measure, with a significance threshold set at p < 0.004. Results: The ES maneuver significantly increased the duration of LVC, pharyngeal constriction, PES opening, and overall swallow duration. It also improved the pharyngeal constriction ratio. However, there were no significant changes in hyoid and laryngeal excursions. Submental muscle activity showed a notable increase during ES. Conclusion: The study demonstrates that ES can effectively modify certain temporal and kinematic aspects of swallowing, particularly by prolonging key phases and enhancing pharyngeal constriction. These findings suggest the potential utility of ES in dysphagia rehabilitation, especially in cases that require prolonged pharyngeal constriction, LVC, and PES opening. However, the limited impact on hyoid and laryngeal excursions along with LVC reaction time indicates that ES may not address all aspects of dysphagia. The findings highlight the need for tailored therapeutic approaches in dysphagia management, considering individual physiological impairment profiles.

Tongue Pressure Resistance Training for Post-Stroke Dysphagia: A Case Study

Introduction: Swallowing outcomes regarding lingual resistance training have been mixed due to variability in methods, leading to ambiguity concerning the utility of this intervention. The purpose of this study was to explore the effect of a lingual resistance training protocol on the swallowing function of an individual presenting with dysphagia and reduced tongue pressure following a supratentorial ischemic stroke. Methods: A study involving a lingual resistance training protocol with videofluoroscopy to measure outcomes comparing different parameters to ASPEKT normative reference values at three timepoints: baseline (videofluoroscopic swallowing study [VFSS] A), following a 4-week lead-in period to control for spontaneous recovery (VFSS B), and at the 8-week endpoint of treatment (VFSS C). The study was interrupted due to the COVID-19 pandemic after 1 participant enrollment and is presented as a single case study. Results: Isometric tongue pressures: Following the 4-week lead-in, a decline in maximum isometric anterior tongue pressure (MAIP) and regular effort saliva swallow pressures (RESS) was noted; however, there was no change in maximum posterior isometric tongue pressures (MPIP). Isometric tongue pressures improved post-treatment, with increases in MAIP, MPIP, and to a lesser degree RESS. Swallowing function: Impairments in swallowing safety continued between the baseline VFSS A (Penetration-Aspiration Scale score [PAS] = 8) and lead-in VFSS B (PAS = 5). Swallowing safety improved following the intervention, with PAS scores = 1 at the endpoint VFSS C. Pixel-based measures of swallowing efficiency revealed a reduced frequency of post-swallow total pharyngeal residue following the treatment. Improvements were found in two other swallowing parameters, laryngeal vestibule closure integrity and pharyngeal area at maximum pharyngeal constriction, at the endpoint VFSS. Conclusion: These pilot data suggest improvements in some swallowing parameters as an outcome of intervention.

Risk Factors of Aspiration in Pediatric Dysphagia: A Videofluoroscopic Swallowing Study Analysis

Objectives: This study examined to identify effective temporal measures to distinguish between aspirators and non-aspirators in young children with dysphagia.Methods: Fortytwo children aged from 1 year to 3 years 11 months were included in this study. All children were referred to Videofluoroscopic Swallowing Study (VFSS) at a tertiary hospital in South Korea. The children were divided into two groups depending on the presence of aspiration: aspirators (N=16) and non-aspirators (N=26). Seven temporal measures were measured to identify swallowing physiologies by using frame-by-frame analysis. A multilevel model with binomial distribution was used to examine which temporal measures better predict group membership.Results: Delayed pharyngeal swallow (DPS), pharyngeal transit time (PTT), and initiation of laryngeal closure (ILC) were significant factors in distinguishing the aspirators from the non-aspirators. DPS was the most useful temporal measure to distinguish between the groups. ILC placed second, followed by PTT. A model including DPS and PTT was the best model to predict the group membership. A model with PTT and ILC ranked second.Conclusion: The findings indicated that an aspiration risk appeared to increase when the bolus stayed longer in the pharynx and initiation of pharyngeal swallow was delayed. Also, the bolus remained in the pharynx for an abnormally longer time while the airway was open in the aspirators. This study suggests that clinicians should not only recognize pathophysiological factors that may increase the aspiration risk but also determine which abnormal physiology is a main factor of aspiration during VFSS.

Correlation between lesion location and dysphagia characteristics in post-stroke patients

ObjectiveTo assess the correlation between lesion location and swallowing function characteristics in post-stroke dysphagia (PSD) patients. Materials and methodsWe enrolled 133 PSD. The patients were divided into supratentorial and infratentorial stroke groups. We compared the measurements in the videofluoroscopic swallowing study (VFSS) with 3ml and 5 ml of diluted and thickened barium liquid data between supratentorial and brainstem stroke groups. We further compared the difference of VFSS measurements between patients with left hemispheric or right hemispheric lesions (further divided into unilateral hemispheric cortical and subcortical subgroups) and brianstem leison stroke group.To explore the lesion location's effect on different bolus volume, the VFSS measurements of 3ml and 5ml in each subgroups were compared respectively. The measurements of VFSS included the oral transit time, soft palate elevation duration, hyoid bone movement duration (HMD), UES opening duration, pharyngeal transit duration (PTD), stage of ansition duration, and laryngeal closure duration (LCD), the upper esophageal sphincter opening (UESO), hyoid bone superior horizontal displacement, and hyoid bone anterior horizontal displacement. General swallowing function was assessed using the Penetration Aspiration Scale (PAS) and Functional Oral Intake Scale (FOIS). We performed the paired t-test, Spearman's correlation, and Kruskal–Wallis test analysis to characterize the parameters among the groups. ResultsFifty-eight patients were assessed in the final analysis. The HMD (p = 0.019), PTD (p = 0.048) and LCD (p = 0.013) were significantly different between the supratentorial and brainstem lesion groups in 5ml volume. The HMD was significantly different (p = 0.045) between the left cortical and brainstem lesion groups. Significant differences in the HMD (p = 0.037) and LCD (p = 0.032) between the left subcortical and brainstem lesion groups were found in 5ml volume bolus. There was no group different when taking the 3ml volume bolus. Regarding the relationship between food bolus volume and swallowing functions, only the UESO demonstrated a significant difference in the subcortical lesion of the right hemisphere (p = 0.0032) compared the 3 ml and 5 ml volume bolus. The PTD demonstrated a moderate correlation with the PAS scores (r = 0.38, p = 0.0044). The HMD (r = 0.32, p = 0.018) and LCD (r = 0.29, p = 0.039) demonstrated weak correlations with the PAS scores. We did not identify any correlation between the VFSS parameters and FOIS scores in each subgroup level. ConclusionThe PSD with brainstem lesion shows more sever dysfunction in the pharyngeal phases. The left hemisphere was engaged in both the oral and pharyngeal phases. Lesions in the bilateral cortical, subcortical, and brainstem regions may impair sensory input.

Dysphagia in Open Partial Horizontal Laryngectomy Type IIa: Quantitative Analysis of Videofluoroscopy using the ASPEKT Method.

Open Partial Horizontal Laryngectomy (OPHL) Type IIa surgery is a conservative surgical technique used in the treatment of laryngeal carcinomas. In this pilot study, we aimed to characterize swallowing function and physiology in a series of patients after OPHL Type IIa surgery through comparison to healthy reference values for quantitative measures for videofluoroscopy. We performed retrospective quantitative analysis of videofluoroscopy recordings of thin liquid swallows for a preliminary sample of 10 male patients. Each videofluoroscopy clip was rated in triplicate by trained blinded raters according to the ASPEKT Method (Analysis of Swallowing Physiology: Events, Kinematics and Timing). This preliminary sample of patients with previous OPHL surgery showed functional airway protection, with only 2 patients showing incomplete laryngeal vestibule closure (LVC) and associated airway invasion. However, the majority of patients (90%) showed prolonged latencies to LVC and upper esophageal sphincter (UES) opening. Prolonged durations of LVC and UES opening were also noted, but these were in the direction of compensation rather than impairment. Reduced pharyngeal area at rest was seen in 70% of the sample, and all patients showed poor pharyngeal constriction. Post-swallow residue was a prominent finding in ≥ 75% of these patients. In particular, reduced or absent constriction of the hypopharynx in the region of the pyriform sinuses was noted as a characteristic of swallowing in this sample. The data from these patients suggest that despite functional airway protection, severe swallowing dysfunction involving poor pharyngeal constriction and bolus clearance may be likely after OPHL surgery.

Comparing biomechanics and neurophysiology between different phenotypes of patients with oropharyngeal dysphagia.

The pathophysiology of oropharyngeal dysphagia (OD) across patient phenotypes may differ. The aim of this study was to compare the biomechanics and neurophysiology of swallowing between healthy volunteers (HVs) and patients with dysphagia as a consequence of aging (OOD), post-stroke (PSOD), Parkinson's disease (POD), or dementia (DOD). A retrospective study including 35 HVs and 109 OOD, 195 PSOD, 78 POD, and 143 DOD patients was performed. Videofluoroscopic data of signs of impaired efficacy and safety, penetration-aspiration scale (PAS) score, and the biomechanics of laryngeal vestibule closure (LVC) and opening (LVO) and of upper esophageal sphincter opening (UESO) were collected. Neurophysiology was assessed with pharyngeal sensory evoked potentials and neurotopography maps. All OD phenotypes showed signs of impaired efficacy and safety of swallowing, increased PAS score (p < 0.001), and delayed time to LVC (p < 0.0001). OOD (p < 0.0001), PSOD (p < 0.0001), and POD (p = 0.0065) patients also had delayed time to LVO, and OOD (p = 0.0062) and DOD (p = 0.0016) patients to UESO. Regarding neurophysiology, all phenotypes presented impaired pharyngeal sensitivity, a significant reduction in cortical activation, and impaired sensory input integration. Additionally, only PSOD was associated with impaired conduction of sensory stimuli. In conclusion, we found common but also specific pathophysiological elements. These results improve our understanding of OD pathophysiology and may help pave the way for phenotype-specific treatments.

Dysphagia Pattern in Early to Moderate Parkinson's Disease Caused by Abnormal Pharyngeal Kinematic Function.

Airway invasion is common in patients with Parkinson's disease (PD) and can cause serious complications. However, a PD-related dysphagic pattern has not been clearly elucidated. In this study, 53 patients with early to moderate PD were enrolled to undergo a videofluoroscopic study of swallowing evaluation (VFSS) and a battery of neuropsychological assessments. A set of VFSS variables (three visuoperceptual, nine temporal, and six spatial) were measured. The main effects of bolus viscosity and volume on airway invasion were calculated. Statistical analyses were performed to determine key kinematic factors of airway invasion for swallowing each bolus type. Airway invasion frequency was significantly higher for liquid boluses (liquid vs. pudding P < 0.001; liquid vs. honey P = 0.006). Laryngeal vestibule closure reaction time (LVCrt) was the key kinematic factor of airway invasion for 3ml liquid swallow (P = 0.040), anterior displacement of hyoid bone was the key kinematic factor for both 5ml and 10ml liquid swallows (P = 0.010, 0.034, respectively). Male sex and advanced Hoehn and Yahr stage were significantly related to reduced anterior displacement of hyoid bone. These results reveal the dysphagic pattern related to PD, demonstrating that prolonged LVCrt and reduced anterior displacement of hyoid bone are two crucial kinematic factors contributing to airway invasion during the liquid swallow. In addition, hyoid bone dysfunction was correlated with disease severity and male sex. Our findings warrant further investigation of the pathophysiological mechanism of dysphagia in PD and would guide clinical intervention.

VIDEOFLUOROSCOPIC EVALUATION OF THE IMPACT OF CAPSULE SIZE AND SUBJECT'S AGE AND GENDER ON CAPSULE SWALLOWING.

People recurrently have difficulties swallowing solid medications, which can be associated with the size of the medication and the age and gender of individuals. To evaluate the impact of capsule size and adults' age and gender on oral and pharyngeal capsule transit during capsule swallows. Videofluoroscopy was used to measure capsule oral and pharyngeal transit during swallows in 49 healthy individuals (17 men and 32 women), with a mean age of 46 years (ranging from 23 to 88 years). Smaller capsules were filled with 0.50 mL of barium sulfate, and larger capsules were filled with 0.95 mL of barium sulfate; the volume of liquid ingested with the capsules was also quantified in each ingestion. The measurements included the oral preparation time, oral transit time, swallowing reaction time, time to laryngeal vestibule closure, laryngeal vestibule closure duration, pharyngeal transit time, and upper esophageal sphincter opening duration. The capsule size did not influence either the oral or pharyngeal transit time. Increased liquid volume was ingested with larger capsules and by people older than 40 years. The oral transit time was shorter in older adults (60-88 years), and the time to laryngeal vestibule closure was longer in women. The size of large capsules did not make a difference in oral or pharyngeal transit when compared with smaller capsules. The capsule size and the participant's age influenced the volume of liquid ingested - larger capsules and older individuals required a larger volume. The capsule oral transit was faster in individuals older than 60 years. •Swallowing is influenced by the characteristics of what is being swallowed. •There was no difference in swallowing capsules containing 0.50 mL or 0.95 mL. •Larger capsules need more liquid ingestion to make swallowing easier. •Individuals older than 40 years need a greater volume of liquid to swallow capsules than younger adults.

Videofluoroscopic measures of swallowing in people with stable COPD compared to healthy aging.

Swallowing impairment is a serious extra-pulmonary manifestation of Chronic Obstructive Pulmonary Disease (COPD). Previous studies suggest that individuals with stable COPD show atypical values for several videofluoroscopy measures of swallowing, compared to healthy adults under age 60. However, it is unclear to what degree these changes are attributable to healthy aging. In this study, we aimed to clarify how swallowing in people with stable COPD differs from age-matched healthy controls. We performed a retrospective analysis of videofluoroscopy data from two previously-collected datasets: a) a sample of 28 adults with stable COPD (18 male); b) a sample of 76 healthy adults, from which 28 adults were selected, matched for sex and age to participants in the COPD cohort. In both prior studies, participants swallowed 20% w/v liquid barium prepared in different consistencies (thin; mildly, moderately, and extremely thick). Blinded duplicate ratings were performed according to a standard procedure, yielding measures of laryngeal vestibule closure (LVC) integrity and timing, swallow timing, upper esophageal sphincter (UES) opening, pharyngeal constriction and pharyngeal residue. Mann-Whitney U tests and odds ratios were performed to determine significant group differences (p<.05). Across the consistencies tested, participants with COPD showed significantly shorter durations of LVC, earlier onsets and shorter durations of UES opening, and reduced pharyngeal constriction. No significant differences were seen in other measures. These results point to features of swallowing in people with stable COPD that differ from changes seen with healthy aging, and which represent risks for potential aspiration.

The Effectiveness of Slightly Thick Liquids for Improving Swallowing in Bottle-Fed Children With Aerodigestive Concerns.

Strategies for facilitating safe and functional bottle feeding in children with dysphagia include selecting nipples that reduce flow rate, pacing, altered positioning, and thickening liquid consistencies. We aimed to determine the impact of slightly thick liquids on swallowing through retrospective review of a convenience sample of clinical videofluoroscopic swallowing studies (VFSS) from 60 bottle-fed children (21 boys and 39 girls, mean age of 9.9 months) referred due to suspected aspiration. Eligible VFSS exams were those in which the child swallowed both thin and slightly thick barium (40% w/v Varibar barium) using the same nipple. VFSS sequences (i.e., uninterrupted portions of the VFSS recording) were randomly assigned in duplicate for rating by trained raters; discrepancies were resolved by consensus. Parameters measured included number of swallows/sequence, sucks/swallow, swallow and sequence duration, number and timing of penetration or aspiration events, laryngeal vestibule closure integrity, and pharyngeal residue. Chi-square tests, linear mixed-model analyses of variance, and Wilcoxon signed-ranks tests identified consistency effects. There were no aspiration events in these recordings. Slightly thick liquids resulted in significantly fewer penetration events (p < .05), increased sucks/swallow, fewer swallows/sequence, and longer swallow and sequence durations. The number of children with ≥ 1 sequence showing pyriform sinus residue was significantly higher with slightly thick liquids. Slightly thick liquids can be effective in reducing penetration in bottle-fed children with dysphagia. However, slightly thick liquids may also lead to a safety-efficiency trade-off, with increased risk of pyriform sinus residue. Thickening for children with dysphagia should be considered only when other approaches are not effective. Overthickening should be avoided to limit negative impact on swallowing efficiency.

Hypopharyngeal geometry impact on air-induced loads on the supraglottis

Exercise-induced laryngeal obstruction (EILO) describes paradoxical laryngeal closure during inspiration at high-intensity exercise. It is hypothesised that during intense activity, the air-induced loads on supraglottic walls overcome their internal stiffness, leading to the obstruction. Recent investigations have revealed that the air-induced loads on the supraglottic walls vary nonlinearly with increasing flow rate. It is, however, unclear whether certain geometric configurations of the hypopharynx and larynx may contribute to the predisposition to EILO. This study investigates the influence of hypopharyngeal and laryngeal geometry on upper respiratory tract airflow and air-induced forces. A computational fluid dynamics model is developed to study airflow through larynx. Four real, adult upper respiratory tracts with variable configurations are considered. Two steady, uniform inspiratory flow rates of 60 L/min and 180 L/min are considered. The analysis shows that geometries with a space lateral to the epiglottis (EpiS) and piriform fossae (PF) directs the hypopharyngeal and supraglottic pressure field to remain positive and increase with the flow rate. In geometries with EpiS and PF, pressure differential occurs around the aryepiglottic fold producing a net inward force over the region. The three-fold increase in flow rate induces near ten-fold increases in force over the region which may facilitate the closure. It is concluded that hypopharyngeal anatomy, particularly the piriform fossae, play a significant role in the obstruction of the supraglottic airway and should be considered in research and clinical assessment of EILO.

Therapeutic Effect on Swallowing Function and on Hydration Status of a New Liquid Gum-Based Thickener in Independently-Living Older Patients with Oropharyngeal Dysphagia

ThickenUp® Gel Express (TUGE) is a new, xanthan- and acacia-gum-based, liquid, thickening product. In independently living older adults with oropharyngeal dysphagia (OD), we assessed: (1) the rheological properties of TUGE; (2) its therapeutic effect at four viscosity levels (achieved by 5 g, 10 g, 20 g and 30 g of TUGE in water + Omnipaque X-ray contrast) versus thin liquid; and (3) the effect on hydration status and gastrointestinal tolerance after fourteen days. Shear viscosity of TUGE was measured in SI units (mPa·s at 50 s−1). The Penetration Aspiration Scale (PAS) score and the swallow response at each viscosity level was assessed with videofluoroscopy (VFS), and in the 14-day study we assessed fluid intake, hydration, and tolerance. Thickened fluids with TUGE were unaffected (−0.3%) by α-salivary amylase (α-SA). The shear viscosity values with VFS were 49.41 ± 2.38, 154.83 ± 10.22, 439.33 ± 11.72 and 672.5 ± 35.62 mPa·s. We studied 60 independently living adults (70 ± 11.4 years) with mild OD (PAS 4.1 ± 2.2, 25% aspirations). TUGE caused a shear-viscosity-dependent improvement in PAS at 150–670 mPa·s and in safety of swallow, slightly increased oral residue, did not affect pharyngeal residue and reduced time to laryngeal vestibule closure (−27%) at 670 mPa·s. Fluid intake with TUGE (1488 mL/day) was well tolerated, and hydration status improved. In conclusion, TUGE was unaffected by α-SA and strongly improved safety of swallow in a viscosity-dependent manner without affecting pharyngeal residue. Fourteen-day treatment of thickened fluids with TUGE is safe and well tolerated and improves hydration status in older adults with dysphagia.

Application of deep learning technology for temporal analysis of videofluoroscopic swallowing studies

Temporal parameters during swallowing are analyzed for objective and quantitative evaluation of videofluoroscopic swallowing studies (VFSS). Manual analysis by clinicians is time-consuming, complicated and prone to human error during interpretation; therefore, automated analysis using deep learning has been attempted. We aimed to develop a model for the automatic measurement of various temporal parameters of swallowing using deep learning. Overall, 547 VFSS video clips were included. Seven temporal parameters were manually measured by two physiatrists as ground-truth data: oral phase duration, pharyngeal delay time, pharyngeal response time, pharyngeal transit time, laryngeal vestibule closure reaction time, laryngeal vestibule closure duration, and upper esophageal sphincter opening duration. ResNet3D was selected as the base model for the deep learning of temporal parameters. The performances of ResNet3D variants were compared with those of the VGG and I3D models used previously. The average accuracy of the proposed ResNet3D variants was from 0.901 to 0.981. The F1 scores and average precision were 0.794 to 0.941 and 0.714 to 0.899, respectively. Compared to the VGG and I3D models, our model achieved the best results in terms of accuracy, F1 score, and average precision values. Through the clinical application of this automatic model, temporal analysis of VFSS will be easier and more accurate.