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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., (© 2024 John Wiley & Sons Ltd.)

Background: Electrical stimulation therapy is effective for patients with dysphagia. However, because of the pain, strong stimulation cannot be applied. Although magnetic stimulation induces less pain, there are no reports on magnetic stimulation being synchronised with a swallowing reflex., Objective: This study aimed to determine whether it is possible to induce magnetic stimulation during a voluntary swallowing using electromyography (EMG)-triggered peripheral magnetic stimulation and to evaluate its effect on healthy individuals., Methods: A total of 20 healthy adults in seated position were instructed to swallow saliva and 10 ml of barium under videofluoroscopy. For concomitant use of magnetic stimulation, a magnetic stimulus for suprahyoid muscles at 30 Hz frequency was applied for 2 s when the EMG level in the sternohyoid muscle exceeded the threshold. During the voluntary swallowing, the movement of the hyoid bone and opening width of the upper oesophageal sphincter (UES) were measured. Furthermore, pressure topography was evaluated in 6 subjects using high-resolution manometry., Results: The magnetic stimulation significantly extended the movement time of the hyoid bone (p < 0.001). During liquid deglutition, significant increases were observed in the anterior maximum movement distance of the hyoid bone (p < 0.05), opening width of the UES (p < 0.001) and anterior movement distance of the hyoid bone at the maximum UES opening (p < 0.01). In the pressure topography, the maximum pressure immediately after UES closure significantly decreased with magnetic stimulation (p < 0.05)., Conclusion: EMG-triggered peripheral magnetic stimulation made it possible to apply magnetic stimulation during a voluntary swallowing., (© 2021 John Wiley & Sons Ltd.)

Purpose: The purpose of this study was to elucidate the effects of the tongue-hold swallow (THS) on the pharyngeal wall by quantifying posterior pharyngeal wall (PPW) anterior bulge during the THS. In addition, the effect of tongue protrusion length on the extent of pharyngeal wall anterior bulge was analysed., Methods: Thirteen healthy subjects (6 males and 7 females, 23-43 years) underwent 320-row area detector CT during saliva swallow (SS) and THS at two tongue protrusion lengths (THS1 protrude the tongue as much as 1/3 of premeasured maximum tongue protrusion length (MTP-L) and THS2 protrude the tongue as much as 2/3 of MTP-L). To acquire images of the pharynx at rest, single-phase volume scanning was performed three times during usual breathing with no tongue protrusion (rest), protrusion of the tongue at 1/3 of MTP-L (rTHS1) and protrusion of the tongue at 2/3 of MTP-L (rTHS2). Length from cervical spine to PPW (PPW-AP) and the volume of pharyngeal cavity was measured and was compared between rest, rTHS1 and rTHS2 and between SS, THS1 and THS2. Correlation between MTP-L and PPW-AP was calculated in three conditions, SS, THS1 and THS2., Results: PPW-AP at rest, rTHS1 and rTHS2 was 2.9 ± 0.6 mm, 3.0 ± 0.5 mm and 3.0 ± 0.5 mm, respectively, showing no significant differences across swallows. PPW-AP at the maximum pharyngeal constriction was 8.1 ± 2.0 mm, 9.1 ± 2.4 mm and 8.7 ± 2.0 mm in SS, THS1 and THS2, respectively. Compared to SS, PPW-AP in THS1 was significantly larger (p = 0.04) and PPW-AP in THS2 was not significantly different (p = 0.09). Pharyngeal volume at rest, rTHS1 and rTHS2 was 16.4 ± 5.2 mm 3 , 18.4 ± 4.5 mm 3 and 21.3 ± 6.2 mm 3 , respectively. It was significantly larger during rTHS2 compared with rest or rTHS1 (rTHS2-rest p = 0.007, rTHS2-rTHS1 p = 0.007). Pharyngeal volume was completely obliterated (zero volume) at maximum pharyngeal contraction in all except one subject. There was no correlation between MTP-L and PPW-AP in any of the three conditions (SS, THS1 and THS2)., Discussion: This study demonstrated that the expanded pharyngeal cavity due to the tongue protrusion was completely obliterated by the increase in anterior motion of pharyngeal wall during THS. It also became clear that the degree of tongue protrusion did not linearly correlate with the movement of PPW during THS. There was no relationship between PPW motion and the MTP-L, suggesting that the effect of tongue protrusion is better determined in each subject by analysing the motion of PPW using imaging tools., (© 2021 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Objective: This study investigated the effects of bolus consistency on pharyngeal volume during swallowing using three-dimensional kinematic analysis., Methods: Eight subjects (2 males and 6 females, mean ± SD 44 ± 10 years old) underwent a 320-row area detector scan during swallows of 10 mL of honey-thick liquid and thin liquid. Critical event timing (hyoid, soft palate, UES) and volume of pharyngeal cavity and bolus were measured and compared between two swallows., Results: The pharynx is almost completely obliterated by pharyngeal constriction against the tongue base for both consistencies. There were no significant differences in maximum volume, minimum volume and pharyngeal volume constriction ratio values between thick and thin liquids. However, the pattern of pharyngeal volume change (decrease) was different. For thick liquids, the air volume started to decrease before the onset of hyoid anterosuperior movement and decreased rapidly after onset of hyoid anterosuperior movement. During thin liquid swallowing, air volume remained relatively large throughout the swallow and started to decrease later when compared to swallowing thick liquids. At onset of UES opening, the bolus volume was not significantly different between thin and thick liquids; however, air volume was significantly larger when swallowing thin liquids, which made the total volume of the pharyngeal cavity larger., Conclusion: This difference between the two consistencies is associated with differences in tongue motion to propel the bolus and clear the pharynx from possible residue., (© 2020 John Wiley & Sons Ltd.)

Background: Dysphagia is a common problem in patients with a history of stroke. In Japan, a reclined position is commonly used as a compensatory technique to address this problem., Objective: To evaluate the effect of reclined position on swallowing function in patients with stroke who had dysphagia., Methods: A retrospective analysis was carried out on the videofluoroscopic examination of swallowing (VF) of 4ml honey-thick liquid swallows collected over 9 years. Penetration-aspiration scale (PAS) and residue scores were compared for the following: a body position at 90° upright (90°U) and 60° reclining (60°R) groups, as well as 60°R and 45° reclining (45°R) groups., Results: Two hundred and five records from 98 subjects were reviewed. These included patients with ischaemic stroke (62%), haemorrhagic stroke (32%) and subarachnoid haemorrhage (6%). PAS scores were lower when the body was in a more reclined position (P < .001). The amount of residue in the valleculae and pyriform sinus also reduced in the more reclined position (P < .001). The deeper bolus head at swallowing onset was positively correlated with severe PAS (P < .001)., Conclusions: These findings suggest that in patients with stroke who had dysphagia, a reclined position may be useful in reducing the risk of penetration and aspiration, and in decreasing the amount of residue in the pharyngeal area. The depth of the bolus head at the onset of swallowing increases the severity of penetration and aspiration., (© 2020 John Wiley & Sons Ltd.)

Swallowing disorder or dysphagia is quite common in hospitalised patients. Using fibre-optic endoscopic evaluation of swallowing (FEES) is one of the clinical standards for evaluating swallowing disorder to prevent serious consequences such as aspiration pneumonia. This study aimed to determine the prevalence and the associated risk of dysphagia in hospitalised patients by using FEES finding. We retrospectively analysed the FEES records from the patients who were screened and suspected of swallowing problems by a certified nurse of dysphagia nursing (CNDN). The FEES findings were compared between dysphagia and without dysphagia to evaluate the associated risk of dysphagia. Six-hundred and nine FEES records were analysed. We found dysphagia 76% in patients who suspected swallowing problems by CNDN. FEES was assessed after the subjects had been admitted for 22 days on average. There was no difference in age between dysphagia and without dysphagia participants. However, the advanced age (age > 85 years old) increased the odd of dysphagia 1.18, P = .03. The primary disease of the subjects was mainly cerebrovascular disease (24%) and pneumonia (22%). Abnormal FEES findings including soft palate elevation, velopharyngeal contraction, whiteout, volitional cough, glottis closure during breath holding, cough reflex and presence of secretion in pharynx were found in hospitalised patients with dysphagia. The prevalence of dysphagia was high in hospitalised patients. Hence, screening the swallowing problem by nurse and FEES evaluation is essential to detect and prevent the complication in the patient who has dysphagia., (© 2020 John Wiley & Sons Ltd.)

Objectives: To assess the effect of age on swallowing with a focus on structural movement, timing and duration of physiologic events., Design: Cross-sectional study., Setting: Tertiary University Medical Center., Participants: Community-dwelling adults (3 age groups): younger 20 to 39 (n = 23; mean 32 ± 5), middle-aged 40 to 59 (n = 29; mean 49 ± 5) and older adults 60 to 74 (n = 15; mean 67 ± 5)., Intervention: One 10-mL honey-thick liquid (1700 mPa) swallow was studied using 320-row area detector computed tomography scanning., Measurements: Kinematic analysis was performed for each swallow including temporal characteristics and structural movements., Results: The duration of velopharyngeal closure and laryngeal closure (including epiglottis inversion, laryngeal vestibule closure, true vocal cord closure) was significantly different by age group (P = 0.002, P < 0.001, P = 0.017, P = 0.041, respectively). Events were prolonged in older adults compared with middle-aged and younger adults. The pharyngeal phase was longer for older adults. Velopharyngeal closure started earlier and continued until after complete UES opening. In younger adults, velopharyngeal and laryngeal opening occurred before complete UES opening. No differences were found in bolus movement through the oropharynx by group., Conclusion: During swallowing, older adults had a longer pharyngeal phase characterised by prolonged velopharyngeal and laryngeal closure. This difference may be a protective mechanism to compensate for age-related weakness. A better understanding of the mechanism by which this adaptation occurs is needed to tailor rehabilitation strategies and to maintain swallowing function during the lifespan., (© 2018 John Wiley & Sons Ltd.)

Swallowing reflex is known to be evoked by gastroesophageal regurgitation or oesophageal stimulation in animal studies. However, details regarding the stimulating material, bolus size and stimulation area remain unclear for the stimulation-induced type of swallowing reflex in humans. Here, we evaluated the effects of different kinds of stimulation via water and air injection of the oesophagus on the initiation of the swallowing reflex. Nine healthy individuals participated in this study. A fibre-optic endoscope was passed transnasally, and a thin catheter for injection was passed through the other side. The tip of the catheter was placed at the upper, upper middle, lower middle or lower region of the oesophagus, and the rate of injection was controlled at 0.2 mL/s. Swallowing reflex latency was calculated as the time from injection via air or thin/thick fluid until the onset of white-out in endoscopic images. Reflex latency was significantly shorter when injection occurred at the upper region of the oesophagus than at the lower region, for both thin and thick fluids (P < .01). At the upper region of the oesophagus, the latency was significantly shorter after injection of thin fluid than with thick fluid (P < .05). Injection of air did not induce the swallowing reflex at all sites. These findings suggest that while the swallowing reflex is evoked by stimulation via fluid injection of the oesophagus in humans, sensitivity is greatest in the upper region of the oesophagus compared with the lower region and can vary depending on the injecting material., (© 2017 John Wiley & Sons Ltd.)

This study investigated the effects of three different volumes of honey-thick liquid on the temporal characteristics of swallowing. Twenty-six healthy subjects (15 males, 11 females) underwent 320-row area detector CT scan while swallowing 3, 10 and 20 mL of honey-thick liquid barium. Three-dimensional images were created at 10 images/s. Kinematic events involving six structures (velopharynx, hyoid bone, epiglottis, laryngeal vestibule (LV), true vocal cords (TVC), upper esophageal sphincter (UES)) and timing of bolus movement were timed using frame by frame analysis. The overall sequence of events did not differ across three volumes; however, increasing bolus volume significantly changed the onset and termination of events. The bolus head reached to pharynx and esophagus earlier and the duration of bolus passing through UES was significantly longer in 10 and 20 mL compared to 3 mL (P < .05). Consequently, the onset of UES opening was significantly earlier with increased volume (P < .05). LV and TVC closure occurred later in 20 mL compared to 3 mL (P < .05). These changes in motion of pharynx and larynx appeared to promote swallow safety by preventing aspiration, suggesting that anatomical structure movements adapt in response to bolus volume. Our findings also suggest that the pharyngeal swallow behaviours may be modified by afferents in the oral cavity. The three-dimensional visualization and quantitative measurements provided by 320-ADCT provide essential benchmarks for understanding swallowing, both normal and abnormal., (© 2017 John Wiley & Sons Ltd.)

Although oropharyngeal and laryngeal structures are essential for swallowing, the three-dimensional (3D) anatomy is not well understood, due in part to limitations of available measuring techniques. This study uses 3D images acquired by 320-row area detector computed tomography ('320-ADCT'), to measure the pharynx and larynx and to investigate the effects of age, gender and height. Fifty-four healthy volunteers (30 male, 24 female, 23-77 years) underwent one single-phase volume scan (0.35 s) with 320-ADCT during resting tidal breathing. Six measurements of the pharynx and two of larynx were performed. Bivariate statistical methods were used to analyse the effects of gender, age and height on these measurements. Length and volume were significantly larger for men than for women for every measurement (P < 0.05) and increased with height (P < 0.05). Multiple regression analysis was performed to understand the interactions of gender, height and age. Gender, height and age each had significant effects on certain values. The volume of the larynx and hypopharynx was significantly affected by height and age. The length of pharynx was associated with gender and age. Length of the vocal folds and distance from the valleculae to the vocal folds were significantly affected by gender (P < 0.05). These results suggest that age, gender and height have independent and interacting effects on the morphology of the pharynx and larynx. Three-dimensional imaging and morphometrics using 320-ADCT are powerful tools for efficiently and reliably observing and measuring the pharynx and larynx., (© 2015 John Wiley & Sons Ltd.)