Keiko Aihara

The super-supraglottic swallow (SSGS) improves laryngeal closure, and head flexion compensates for inadequate closure of the airway. These two procedures are typically utilized by speech-language pathologists for specific patient populations. This study compared the effect of the SSGS with head flexion (i.e., modified SSGS [mSSGS]) on laryngeal closure with that of usual swallowing and the SSGS in healthy individuals. Twenty-one healthy volunteers were instructed to swallow 4 ml of thin liquid barium in a sitting position during usual swallowing, SSGS, and mSSGS under X-ray fluoroscopy. The primary outcome was the distance between the epiglottis and arytenoid (DEA) at onset of the swallowing reflex. The secondary outcomes were DEA before onset of the swallowing reflex, the head flexion angle before and at onset of the swallowing reflex, and the Penetration-Aspiration Scale (PAS) score. The relative ease of performing the mSSGS compared with the SSGS was evaluated using a 7-point Likert scale. DEA at onset of the swallowing reflex was significantly shorter with mSSGS than with usual swallowing (P < 0.001) or the SSGS (P = 0.006). DEA before swallowing was also significantly shorter with the mSSGS than with usual swallowing (P < 0.001) and the SSGS (P = 0.006). PAS score was 1 in all trials. The median Likert score was 3, indicating that the SSGS was easier than the mSSGS. The findings suggest that the mSSGS maneuver enhances laryngeal closure more than the SSGS maneuver and usual swallowing.

This study aimed to establish reference values for quantitative measurements of pharyngeal volume and residue during swallowing in healthy individuals and to examine how these measurements are influenced by age, sex, height, and bolus properties. We performed a retrospective analysis of 288 swallows from 135 healthy Japanese adults (median age, 43 years; height, 163 cm) who underwent Swallowing CT. Test boluses included thin or extremely thick liquids in either 3 mL, 10 mL, or 20 mL amounts. Pharyngeal cavity volume at bolus hold (PVHOLD), unobliterated air and bolus volume at maximum pharyngeal constriction (PVMAX), and pharyngeal volume constriction ratio (PVCR), and post-swallow pharyngeal residue were measured on dynamic 3D-CT images using a semi-automated software. We determined the 2.5th, 50th, 97.5th percentile values to obtain normative reference values for each parameter and made generalized linear regression models to determine how these volume measurements are associated with demographic factors and bolus properties. Normative values (median [97.5th percentile]) across all swallows were PVHOLD 20.9 cm3 [38.6 cm3], PVMAX 0.3 cm3 [2.1 cm3], PVCR 98.8% [2.5th percentile 89.1%], and residue 0 cm3 [0.4 cm3]. Males exhibited larger values than females. PVHOLD significantly increased with height (β = 0.465, p < 0.001) and age (β = 0.068, p = 0.001), while PVMAX and PVCR increased with larger bolus volumes (β = 0.293, p = 0.005) and in thicker consistencies (β = 0.376, p = 0.017). Pharyngeal residue was present in 98/288 (34.0%) of swallows and was significantly associated with increasing bolus volume (adjusted odds ratio [aOR] = 1.865 [95% confidence interval: 1.275-2.727]), age (aOR = 1.025 [1.010-1.040]), thicker bolus (aOR = 1.806 [1.275-2.727]). Each 1 cm2 increase in PVMAX was associated with nearly double the odds of residue (aOR = 1.86 [1.202-2.862]). Similarly, each 1% decrease in PVCR corresponded to a 10.6% increase in the odds of residue (aOR = 1.106 [1.015-1.295]). These normative data provide a bases for comparing individuals with or without pharyngeal impairments.

This study aimed to determine the impact of bolus volume on UES opening. Twenty-two healthy subjects (10 males and 12 females, 23-45 years) underwent a CT scan while swallowing 3-, 10-, and 20 ml of thin liquid. Upper esophageal sphincter (UES) cross-sectional area and hyoid and laryngeal displacement were measured at every frame across three conditions. The timing of UES opening onset, UES maximum opening, and duration of UES opening were also measured. With increasing bolus volume, the UES maximum opening area increased, at the UES opening onset, at the UES maximum opening was earlier, and the duration of the UES opening prolonged. The maximum displacement of the hyoid and larynx was significantly more anteriorly and higher with a large bolus volume. However, the hyoid displacement at the timing of UES maximum opening did not change across three bolus volumes. This result suggests that the increase in the UES maximum opening area with increasing bolus volume was modulated by the bolus itself rather than by the hyoid movement.

This study evaluated the validity of pharyngeal 2D area measurements acquired from the lateral view for predicting the actual 3D volume in healthy adults during swallowing. Seventy-five healthy adults (39 females, 36 males; mean age 51.3 years) were examined using 320-row area detector computed tomography (320-ADCT). All participants swallowed a 10 mL honey-thick barium bolus upon command while seated in a 45° semi-reclining position. Multi-planar reconstruction images and dynamic 3D-CT images were obtained using Aquilion ONE software. Pharyngeal 2D area and 3D volume measurements were taken before swallowing and at the frame depicting maximum pharyngeal constriction. Pharyngeal volume before swallowing (PVhold) was accurately predicted by 2D area (R2 = 0.816). Adding height and sex to the model increased R2 to 0.836. Regarding pharyngeal volume during maximum constriction (PVmax), 2D area also exhibited acceptable predictive power (R2 = 0.777). However, analysis of statistical residuals and outliers revealed a greater tendency for prediction errors when there is less complete constriction of the pharynx as well as asymmetry in bolus flow or movement. Findings highlight the importance of routinely incorporating anterior-posterior views during VFSS exams. Future work is needed to determine clinical utility of pharyngeal volume measurements derived from 320-ADCT.

BACKGROUND: Upper oesophageal sphincter (UES) serves as an important anatomical and functional landmark during swallowing. However, the precise UES location before and during swallowing has not been well established. OBJECTIVE: This study aimed to determine upper oesophageal sphincter (UES) location and displacement during swallowing accounting for sex, age, and height in healthy adults using 320-row area detector computed tomography (320-ADCT). METHODS: Ninety-four healthy adults (43 males; 22-90 years) underwent 320-ADCT scanning while swallowing one trial of 10 mL honey thick barium. UES location at bolus hold and at maximum displacement and vertical displacement during swallowing were identified using the coordinates and the section classification of vertebrae (VERT scale). The differences and correlations of UES location and distance in terms of sex, age, and height were analysed using Mann-Whitney U test and Spearman's correlation coefficient. RESULTS: UES locations at bolus hold and at maximum displacement were significantly lower and UES vertical displacement was significantly larger in males than in females (p < .001). UES location at bolus hold became lower with increasing age (r = -.312, p = .002), but the negative correlation was low at maximum displacement (r = -.230, p = .026), resulting in larger vertical distance with ageing. UES locations showed high negative correlation at bolus hold with height (r = -.715, p < .001), and showed moderate negative correlation at maximum displacement with height (r = -.555, p < .001), although this effect was unclear when analysed by sex. CONCLUSION: Males showed lower UES location and larger displacement than females. The impact of age was evident with lower location before swallowing and larger displacement during swallowing. Differences observed by sex were not completely explained by using the VERT scale to adjust for height.