Improvement of oral function and its impact on oral food intake in subacute stroke patients: A prospective study with dental intervention.

BACKGROUND: The association between oral food intake and oral function during the subacute stage of stroke is not well known. OBJECTIVE: To investigate (1) oral function changes in subacute stroke patients and (2) association between oral function and oral intake status at several time points. METHODS: In a prospective study involving 324 stroke patients at a convalescent rehabilitation unit, four oral function parameters (maximum tongue pressure, MTP; lip-tongue motor function, LTMF; maximum occlusal force, MOF and oral health assessment tool, OHAT) were quantitatively measured upon admission (T0), at 1 month (T1) and 2 months (T2). Oral feeding status was assessed using the Functional Oral Intake Scale (FOIS) and divided based on the FOIS score into the dysphagic and regular diet groups. The changes in oral functions at the three time points were tested using generalized estimating equation analysis. The association between FOIS groups and oral functions at T1 and T2 was analysed by means of logistic regression analysis. RESULTS: All oral function parameters improved significantly over time during the hospital stay (mean differences: 4.9 for MTP, 0.6 for LTMF, 1.1 for MOF and -1.8 for OHAT). The FOIS groups were significantly associated with MTP (p < .05) and OHAT (p < .05) at both T1 and T2. CONCLUSION: Our findings suggest that oral function significantly improves in patients during subacute stroke rehabilitation and better oral health can be associated with better oral intake. Improved oral function through dental intervention and oral rehabilitation may contribute to gains in oral food intake.

Location of the upper oesophageal sphincter during swallowing: Analysis using swallowing CT.

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.

Effect of the Effortful Swallow on Pharyngeal Cavity Volume: Kinematic Analysis in Three Dimensions Using 320-Row Area Detector Computed Tomography.

This study evaluated the effects of the effortful swallow (ES) on pharyngeal cavity volume using three-dimensional kinematic analyses. Nine healthy volunteers (30.7 ± 7.8 years old) underwent a CT scan while swallowing 10 ml of honey thick liquid using no maneuvers (control) and during an ES. Upper and lower volumes (bordered by valleculae) of the pharyngeal air column and the bolus were measured at every frame and were compared between ES and control swallows. Duration of pharyngeal obliteration and the timing of swallowing events were also measured. Maximum volume and volume at the onset of hyoid anterosuperior movement using ES were significantly smaller than those in control swallows (p = 0.012, p = 0.015) in the upper pharynx but not significantly different in lower pharynx. Minimum pharyngeal volume was sustained for a longer time when ES was used compared to control swallows in both upper and lower pharynx (upper p = 0.016, lower p = 0.027). Onset of velopharyngeal closure was earlier when comparing ES and control swallows (p = 0.04). Termination of all events was significantly delayed when the ES was used (p < 0.05). Changes in the upper pharyngeal volume and in the onset of velopharyngeal closure suggest earlier pharyngeal constriction when using the ES. Longer pharyngeal obliteration and prolonged termination of velopharyngeal closure and epiglottis inversion suggest the prolonged pharyngeal constriction during the ES. These findings suggest the ES can be useful for improving the efficiency of swallowing.

Thin Liquid Bolus Volume Alters Pharyngeal Swallowing: Kinematic Analysis Using 3D Dynamic CT.

The previous studies reported that different volumes of thick liquid had an impact on spatiotemporal characteristics and pharyngeal response of swallowing. However, the bolus flow and swallowing motion pattern were different between thick and thin liquids. The effects of thin bolus volume on pharyngeal swallowing, especially true vocal cord (TVC) closure is still unclear. This study assessed the temporal characteristics when swallowing different volumes of thin liquid to determine the mechanical adaptation using 320-row area detector computed tomography (320-ADCT) and investigated a change of swallowing physiology including laryngeal closure, particularly TVC closure. Fourteen healthy women (28-45 years) underwent 320-ADCT while swallowing of 3, 10, and 20 ml of thin liquid barium in 45° semi-reclining position. Kinematic analysis was performed for each swallow including temporal characteristic, structural movements while swallowing, and maximal cross-sectional area of the upper esophageal sphincter (UES) opening. Bolus head reached to pharynx and esophagus earlier in larger volume significantly, indicating faster bolus transport as volume increased. There were significant effects on swallowing mechanism revealing earlier TVC closure and UES opening with increasing volume. Maximum cross-sectional area of the UES opening was increased to accommodate a larger bolus. Differences in mechanical adaptation through bolus transit and motion of swallowing structures were detected across increasing volumes. These volume-dependent adaptations potentially reduce the risk of aspiration. Understanding the swallowing physiological changes as volume increased is helpful for diagnosis and treatment of dysphagia patients as well as outcomes of swallowing rehabilitation in clinical practice.

Effects of head flexion posture in patients with dysphagia.

BACKGROUND: The chin-down posture is often used as a compensatory manoeuvre for patients with dysphagia. This posture presumably involves flexion of the head and/or neck, but this is not clearly defined. OBJECTIVE: This study aimed to assess the effects of head flexion posture in a retrospective study of videofluoroscopic examination of swallowing (VF). METHODS: A total of 73 patients who underwent VF both with and without head flexion posture in the lateral projection were included in the analysis. The head and neck angles at the initiation of the swallowing reflex, penetration-aspiration scale (PAS), nasopharyngeal closure time, stage transition duration, duration of laryngeal closure, time from swallowing reflex to laryngeal closure and to the opening of upper oesophageal sphincter (UES), duration of UES opening, location of the bolus leading edge at swallowing reflex, and bolus transition time were evaluated. RESULTS: The head flexion angle increased (p < 0.001), but the neck flexion angle did not change in the head flexion posture. Moreover, PAS improved (p < 0.001), aspiration was reduced (p < 0.001), the time between the swallowing reflex and the onset of laryngeal closure was shortened (p = 0.006), and the leading edge of the bolus at swallowing reflex became shallower (p = 0.004) in the head flexion posture. Other parameters did not significantly change. CONCLUSION: The head flexion posture resulted in earlier laryngeal closure and a shallower position of the leading bolus edge at swallowing reflex, resulting in PAS improvement and decreased aspiration.

Stroke Patients with Nearly Independent Transfer Ability are at High Risk of Falling.

OBJECTIVES: To examine the relationship between patients' transfer ability and fall risk in stroke patients during hospitalization. MATERIALS AND METHODS: We retrospectively enrolled 237 stroke patients who were transferred to a convalescent rehabilitation ward from acute wards in the same hospital. Using incident reports, we investigated their fall rates and activity status at the falls according to their transfer abilities, which were assessed with Functional Independence Measure (FIM) transfer scores. The bi-weekly time trend of fall rates in all patients and in three subgroups based on FIM transfer scores of 1-3, 4-5, and 6-7, and activity status at the falls, were investigated. In addition, changes of patients' transfer ability on admission, at the first fall, and at discharge were investigated among falling patients. RESULTS: The fall rate was the greatest in patients with a FIM transfer score of 4 (14.3 times/1000 person-days). The majority of falls for patients with a FIM transfer score of 1 occurred at the activity status of "on the bed" and "sitting", while three quarters of patients with a FIM score of 7 had falls during "standing" and "walking". No longitudinal trend in fall rates was found overall; however, the fall rate trends differed depending on the FIM transfer score. The majority of the patients who fell required full assistance for transfers upon admission but required no assistance at discharge. CONCLUSIONS: Fall risk differed among patients with various transfer abilities; the greatest risk was in those who needed minimal assistance for transfers.

Association between oral health status and oral food intake level in subacute stroke patients admitted to a convalescent rehabilitation unit.

BACKGROUND: Stroke patients often suffer from dysphagia during their recovery. We hypothesised that subacute stroke patients with dysphagia had more deteriorated oral health status including muscle strength and motor function. OBJECTIVE: Quantitatively investigate oral health status and identify associations with oral feeding status in stroke patients admitted to a convalescent rehabilitation unit. METHODS: We prospectively recruited 187 stroke patients admitted to a convalescent rehabilitation unit. Oral feeding status was examined using the Functional Oral Intake Scale (FOIS), and the cohort was divided into three groups based on FOIS score as non-oral feeding (FOIS-123; 22 patients), dysphagic diet (FOIS-45; 74 patients), and regular diet (FOIS-67; 91 patients) groups. Activities of daily living (ADL) were assessed with the Functional Independence Measure (FIM). Oral health status was measured quantitatively in six oral function parameters and Oral Health Assessment Tool (OHAT), and differences according to the FOIS, age and FIM were statistically tested. RESULTS: In bivariate analysis, two parameters, tongue pressure and tongue-lip motor functions were significantly higher in the regular diet group than in the other groups (P < .01). Gross OHAT score was also significantly better in the regular diet group than in the other groups (P < .01). These significant associations mostly remained in the multiple model after adjusting for age and FIM. CONCLUSION: This study suggests that, amongst oral health status, tongue strength and motor function, as well as OHAT score, may have strong associations with oral feeding status in subacute stroke patients at convalescent rehabilitation units regardless of ADL levels.

Effect of electromyography-triggered peripheral magnetic stimulation on voluntary swallow in healthy humans.

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.

Effect of tongue-hold swallow on posterior pharyngeal wall using dynamic area detector computed tomography.

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 mm3 , 18.4 ± 4.5 mm3 and 21.3 ± 6.2 mm3 , 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.

Repetitive Peripheral Magnetic Stimulation for Strengthening of the Suprahyoid Muscles: A Randomized Controlled Trial.

OBJECTIVE: Head lift exercise is a widely known form of training in the rehabilitation of patients with dysphagia. This study aimed to compare muscular strength reinforcement training of the suprahyoid muscles using repetitive peripheral magnetic stimulation (rPMS) with head lift exercises in a randomized controlled trial. MATERIALS AND METHODS: Twenty-four healthy adults were randomly assigned to either the magnetic stimulation group (M group) or the head lift exercise group (H group). Both groups underwent training five days a week for two weeks. The primary outcome was the cervical flexor strength, and secondary outcomes were jaw-opening force, tongue pressure, muscle fatigue of the hyoid and laryngeal muscles, displacement of the hyoid bone and opening width of the upper esophageal sphincter (UES) while swallowing 10 mL of liquid, training performance rate, and pain. RESULTS: No dropouts were reported during the two-week intervention period. Cervical flexor strength significantly increased solely in the M group. Tongue pressure significantly improved in both groups. There were no significant differences in the jaw-opening force, median frequency rate of the anterior belly of the digastric muscle, sternohyoid muscle, sternocleidomastoid muscle, anterior and superior hyoid bone displacement, and UES opening width in both groups. CONCLUSIONS: Two-week rPMS of the suprahyoid muscles increased the strength of these muscles compared with the head lift exercise during the same period.

The effect of reclining position on swallowing function in stroke patients with dysphagia.

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.

The prevalence and findings of fibre-optic endoscopic evaluation of swallowing in hospitalised patients with dysphagia.

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.

The effect of bolus consistency on pharyngeal volume during swallowing: Kinematic analysis in three dimensions using dynamic Area Detector CT.

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.

Control of Emissive Excited States of Silver(I) Halogenido Coordination Polymers by a Solid Solution Approach.

Luminescent silver(I) halogenido coordination polymers [Ag2X2(PPh3)2(bpy)] n (X = I, Br, Cl) have been prepared. The iodido and bromido complexes exhibit strong blue phosphorescence assignable to the 3π-π*-excited-state of bpy, whereas the chlorido complex shows luminescence thermochromism due to the π-π*-state of bpy and charge transfer from the {Ag2Cl2} core to the bpy π*-orbital. Taking advantage of their structural similarities, we prepared a series of mixed-halogenido silver(I) complexes [Ag2(X xX'(1- x))2(PPh3)2(bpy)] n (X, X' = I, Br, Cl) at varying molar fractions as solid solutions. The mixed-halogenido complexes are as strongly luminescent as their parent complexes. The detailed study of their structure and emissive properties revealed smooth energy migration between the luminescent units and modification of the luminescence properties based on the planarity of bpy.

The Association of 3-D Volume and 2-D Area of Post-swallow Pharyngeal Residue on CT Imaging.

Pharyngeal residue, the material that remains in the pharynx after swallowing, is an important marker of impairments in swallowing and prandial aspiration risk. The goals of this study were to determine whether the 2D area of post-swallow residue accurately represents its 3D volume, and if the laterality of residue would affect this association. Thirteen patients with dysphagia due to brainstem stroke completed dynamic 320-detector row computed tomography while swallowing a trial of 10 ml honey-thick barium. 3D volumes of pharyngeal residue were compared to 2D lateral and anterior-posterior areas, and a laterality index for residue location was computed. Although the anteroposterior area of residue was larger than the lateral area, the two measures were positively correlated with one another and with residue volume. On separate bivariate regression analyses, residue volume was accurately predicted by both lateral (R2 = 0.91) and anteroposterior (R2 = 0.88) residue areas, with limited incidence of high residuals. Half of the sample demonstrated a majority of pharyngeal residue lateralized to one side of the pharynx, with no effect of laterality on the association between areas and volume. In conclusion, the area of post-swallow pharyngeal residue was associated with volume, with limitations in specific cases. Direct measurement of pharyngeal residue volume and swallowing physiology with 3D-CT can be used to validate results from standard 2D instrumentation.

Hyoid Bone Movement at Rest by Peripheral Magnetic Stimulation of Suprahyoid Muscles in Normal Individuals.

OBJECTIVES: Neuromuscular electrical stimulation has been widely used in patients with dysphagia. However, obtaining sufficient hyoid bone movement through surface electrodes seems difficult. The aim of this study was to evaluate hyoid bone movement at rest through peripheral magnetic stimulation of the suprahyoid muscles in normal individuals. METHODS: Healthy adult men were recruited. A specially designed coil was connected to the peripheral magnetic stimulator. The coil was placed on the submental area of the subjects. Magnetic stimulation was performed at 30 Hz for 2 sec. The intensity level selected induces hyoid bone movement without causing intolerable pain to the subjects. The hyoid bone at rest between on- and off-magnetic stimulations of the suprahyoid muscles were identified using fluoroscopy at 30 frames/sec in lateral projection. Pain during peripheral magnetic stimulation was evaluated using the numerical rating scale (NRS). RESULTS: Eleven subjects aged 32 ± 9 years participated in this study. Magnetic stimulation resulted in 10.9 ± 2.8 mm forward displacement and 8.3 ± 4.1 mm (mean ± SD) upward displacement of the hyoid bone. The median NRS score during magnetic stimulation was 1. CONCLUSIONS: Peripheral magnetic stimulation is noninvasive and easy to perform. It does not require skin preparation, facilitates sufficient hyoid bone movement, and causes minimum level of pain.

The Mendelsohn Maneuver and its Effects on Swallowing: Kinematic Analysis in Three Dimensions Using Dynamic Area Detector CT.

This study investigated the effects of Mendelsohn maneuver with three-dimensional kinematic analysis. Nine female speech-language pathologists (nine females, mean ± SD 27.1 ± 3.5 years old) underwent 320-row area detector scan during swallows of 4-ml nectar-thick liquid using with no maneuvers (control) and with Mendelsohn maneuver (MM). Critical event timing (hyoid, soft palate, epiglottis, laryngeal vestibule, true vocal cords (TVC), UES), hyoid and laryngeal excursion, cross-sectional area of UES, and volume of pharyngeal cavity and bolus were measured and compared between two swallows. In MM, all the events were significantly prolonged with delayed termination time (p < 0.05) except UES opening. The onset, termination, and duration of UES opening were not significantly affected by MM nor was timing of bolus transport. The hyoid bone was positioned significantly higher at maximum displacement (p = 0.011). Pharyngeal constriction ratio was 95.1% in control and 100% of all subjects in MM. Duration of minimum pharyngeal volume was significantly longer in MM than in control (p = 0.007). The MM produces several distinct changes in the kinematics of swallowing in healthy subjects with no dysphagia. The changes in the timing and magnitude of hyoid displacements and prolonged closure of the pharynx during swallowing suggest the utility of MM for improving the safety and efficiency of swallowing in selected cases.

Pharyngeal swallowing in older adults: Kinematic analysis using three-dimensional dynamic computed tomography.

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.

Measurement of Pharyngo-laryngeal Volume During Swallowing Using 320-Row Area Detector Computed Tomography.

This study aimed to (1) evaluate changes in bolus and air volumes in the pharyngo-laryngeal cavity during swallowing and (2) determine how differences in these volumes during swallowing are influenced by bolus amount using 320-row area detector computed tomography (320-ADCT). Three-, 10-, and 20-ml honey-thick liquids (5% w/v) were presented to ten healthy subjects placed in a 45° reclining position. 3D images were created in 29 phases at an interval of 0.1 s for 3.15 s. Changes in bolus and air volumes in the pharyngo-laryngeal cavity were calculated. The two one-sided tests were used to determine equivalency of the pharyngo-laryngeal volume of each event (i.e., onset of hyoid elevation, soft palate closure, true vocal cord closure, closure of laryngeal vestibule, epiglottis inversion, pharyngo-esophageal sphincter opening) for each bolus volume. The pharyngo-laryngeal volume during swallowing was about 20 ml before swallowing. The volume temporarily increased with tongue loading, but decreased to about 0 ml with pharyngeal contraction. Subsequently, the volume returned to the original volume after airway opening. Most of the air was released from the pharyngo-laryngeal space before the bolus flowed into the esophagus during swallowing. As the bolus volume to be swallowed increased, the maximal pharyngo-laryngeal volume increased, but changes in air volume remained constant. 320-ADCT allowed for analysis of dynamic volume changes in the pharyngo-laryngeal cavity, which will increase our knowledge of kinematic and volumetric mechanisms during swallowing.