Measuring Hyoid Excursion Across the Life Span: Anatomical Scaling to Control for Variation

Alterations in Swallowing Six Weeks After Primary Anterior Cervical Discectomy and Fusion (ACDF)

This aim of this study is to characterize the nature and pathophysiology of dysphagia after ACDF surgery by precisely and comprehensively capturing within-subject changes on videofluoroscopy between preoperative and postoperative time points. 21 adults undergoing planned primary ACDF procedures were prospectively recruited and enrolled. Participants underwent standardized preoperative and six-week postoperative videofluoroscopic swallow studies. Videos were blindly rated using the Penetration-Aspiration Scale (PAS) and analysis of total pharyngeal residue (%C2-42), swallowing timing, kinematics, and anatomic change was completed. Linear mixed-effects modeling was used to explore the relationships between possible predictor variables and functional outcomes of interest that changed across timepoints. There was no change in PAS scores across timepoints. Total pharyngeal residue (%C2-C42) was increased postoperatively (p < 0.001). Our statistical model revealed significant main effects for timepoint (p = 0.002), maximum pharyngeal constriction area (MPCAN) (p < 0.001), and maximum thickness of posterior pharyngeal (PPWTMAX) (p = 0.004) on the expression of total pharyngeal residue. There were significant two-way interactions for timepoint and MPCAN (p = 0.028), timepoint and PPWTMAX (p = 0.005), and MPCAN and PPWTMAX (p = 0.010). Unsurprisingly, we found a significant three-way interaction between these three predictors (p = 0.027). Our findings suggest that in planned ACDF procedures without known complications, swallowing efficiency is more likely to be impaired than airway protection six weeks after surgery. The manifestation of impaired swallowing efficiency at this timepoint appears to be driven by a complex relationship between reduced pharyngeal constriction and increased prevertebral edema.

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.

Normal Variations in Upper Esophageal Sphincter Function During Deglutition: A Secondary Analysis of Videofluoroscopic Data

OBJECTIVE

Cricopharyngeal dysfunction is a common potential cause of pharyngoesophageal dysphagia. Contextual factors (i.e., personal demographics and bolus properties) appear to impact upper esophageal sphincter (UES) function but have yet to be assessed collectively in a large-scale study using psychometrically sound swallow task procedures. Using a standardized and validated videofluoroscopic approach, we investigated the collective effects of age, sex, and swallow task on UES opening duration (UESOdur) and UES maximum distension (UESmax) in a large sample of healthy adults.

METHODS

UESOdur and UESmax data were analyzed from existing videofluoroscopic images of 195 healthy adults (21-89 years old) across seven swallow tasks (thin liquid to viscous liquids, puree, and a solid). Generalized estimating equation modeling captured the effects of the aforementioned contextual factors (α = 0.05).

RESULTS

UESOdur significantly increased with age, while UESmax had an inverse relationship. Females had significantly wider UESmax. UESOdur of 5 mL thin liquid was significantly shorter than all other liquid swallow tasks, while solid had an inverse effect. Compared to 5 mL thin liquid, all other swallow tasks resulted in significantly wider UESmax. Mildly and moderately thick liquid significantly increased UESOdur when isolating viscosity. UESmax was significantly wider with mildly and moderately thick liquid and puree than thin liquid. When isolating volume, cup sip thin liquid increased both measures significantly relative to 5 mL.

CONCLUSION

Age, sex, and swallow task can influence the normal timing and extent of UES movement. These collective effects contribute to normal variability in UES function and should be considered for clinical decision-making.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2306-2315, 2024.

Swallowing kinematics and submental muscles activation during a newly designed maneuver called Mouth Open Swallowing Maneuver: A comparative study

The aim of this study was to design a new maneuver called the Mouth Open Swallowing Maneuver (MOSM), and to compare swallowing kinematics and submental muscles activation (SMA) between MOSM and two current approaches used in dysphagia rehabilitation. Fifty healthy volunteers were asked to perform three repetitions of dry swallowing (DS) (control task), the MOSM, the Mendelsohn Maneuver (MM), and the Tongue-Hold Maneuver (THM) during videofluoroscopic swallowing study accompanied with simultaneous SMA recording. Swallowing kinematics were measured by frame-by-frame analysis on hyolaryngeal movement using ImageJ. Swallowing with maximum hyolaryngeal movement and SMA during these tasks was used for comparative analysis. Vertical movement of the hyoid during the MOSM was significantly greater than those observed during the DS and the THM (p<0.001, p<0.001). Horizontal movement of the hyoid during DS and the THM was significantly greater than that observed during the MM (p = 0.001, p = 0.001). Vertical movement of the larynx during the MOSM was significantly greater than those observed during DS, MM, and THM (p<0.001). There was no significant difference between tasks in horizontal movement of the larynx (p = 0.785). SMA during the THM was significantly greater than that observed during MOSM (p = 0.002). No significant difference was found between other tasks in terms of SMA (p>0.05). The MOSM as a newly designed maneuver was significantly superior to other maneuvers in increasing vertical hyolaryngeal movement. The THM has as much effect on hyolaryngeal movement as the MM. In this study, the MOSM was shown to be effective in increasing hyolaryngeal movement. ClinicalTrials.gov Protocol Registration and Results System (PRS); the clinical trial registration number (NCT05579041).

Radiographic Magnification on Videofluoroscopy: An Important Variable to Consider for Scaled Analyses of Swallowing

PURPOSE

Traditionally, kinematic measures on videofluoroscopy require the use of an external scalar (such as a penny) to transform pixels to absolute distances. Videofluoroscopy is subject to image magnification based on the distance of the feature of interest to the X-ray source. However, the impact of the position/location of the external scalar on swallowing measures is unknown. Our goal was to systematically investigate the accuracy of various common external scalar locations in lateral and anterior-posterior (A-P) view.

METHOD

U.S. pennies were taped to a styrofoam head in three positions (on the left and right lateral neck and in midline submentally). Locations were measured to ensure equal left and right, as well as midline, placement. A metal screwdriver (6 mm in diameter) was inserted into the premanufactured hole that is centrally located at the bottom of the styrofoam head. The head was centered on a medical tray and placed in the middle of a Siemens Alpha C-arm Fluoroscope field. ImageJ was used to measure penny length in pixels (three locations) in both lateral and A-P views. Penny length was known (19.05 mm), and, therefore, used to derive screwdriver size (for each location) for comparison to the actual screwdriver size.

RESULTS

All scalars overestimated the screwdriver size ranging from 6.55 to 7.87 mm, representing a 9%-31% inflation. Scalars closer to the X-ray source had the largest magnification.

CONCLUSIONS

Our results confirm that image magnification of external scalars is a significant source of variability that is currently unaccounted for in the swallowing literature. Recommendations for future research design/measurement methods are provided.

Defining Normal Sequential Swallowing Biomechanics

Little is known about the physiology of a common fluid ingestion pattern-sequential swallowing. This study investigated sequential swallowing biomechanics in healthy adults. Archival normative videofluoroscopic swallow studies were analyzed for hyolaryngeal complex (HLC) patterning and biomechanical measures from the first 2 swallows of a 90-mL thin liquid sequential swallow task. The effects of age, sex, HLC type, and swallow order were explored. Eighty-eight participants were included in the primary analyses as they performed sequential swallows. HLC Type I (airway opens, epiglottis approaches baseline) and Type II (airway remains closed, epiglottis remains inverted) most commonly occurred (47% each), followed by Type III (mixed, 6%). Age was significantly associated with Type II and longer hypopharyngeal transit, total pharyngeal transit (TPT), swallow reaction time (SRT), and duration to maximum hyoid elevation. Males demonstrated significantly greater maximum hyoid displacement (Hmax) and longer duration of maximum hyoid displacement. Significantly larger maximum hyoid-to-larynx approximation was linked to the first swallow, while the subsequent swallow had significantly longer oropharyngeal transit, TPT, and SRT. Secondary analyses included an additional 91 participants who performed a series of discrete swallows for the same swallow task. Type II had significantly greater Hmax than Type I and series of discrete swallows. Sequential swallowing biomechanics differ from discrete swallows, and normal variance exists among healthy adults. In vulnerable populations, sequential swallowing may challenge swallow coordination and airway protection. Normative data allow comparison to dysphagic populations. Systematic efforts are needed to further standardize a definition for sequential swallowing.

Hyolaryngeal Movement During Normal and Effortful Swallows Determined During Ultrasonography

PURPOSE

This study investigated (a) the effects of the effortful swallow under two different instructions (tongue emphasis vs. pharyngeal squeezing) on hyoid displacement and hyoid-larynx approximation, (b) the association between tongue pressure and hyolaryngeal movement during normal swallowing and the effortful swallow produced with tongue emphasis, and (c) age-related differences in hyolaryngeal movement during normal and effortful swallows (tongue emphasis vs. pharyngeal squeezing) in healthy individuals.

METHOD

Forty healthy adults (20 younger and 20 older) swallowed their saliva as they normally do (normal swallow) and performed the effortful swallow with tongue emphasis and pharyngeal squeezing. Tongue-to-palate pressure during swallowing was measured using the Iowa Oral Performance Instrument, hyolaryngeal movement was measured using ultrasonography, and submental surface electromyography was used to track swallows.

RESULTS

Results revealed differences in hyolaryngeal movement across swallowing types. Both types of effortful swallows showed greater hyolaryngeal movement than normal swallows. Additionally, hyolaryngeal movement was greater during the effortful swallow with tongue emphasis than the effortful swallow with pharyngeal squeezing. Age-related differences were found only in hyoid-larynx approximation during the effortful swallow with tongue emphasis (younger > older adults). Furthermore, moderate positive correlations were identified between tongue pressure and hyolaryngeal movement during normal swallows and the effortful swallow with tongue emphasis.

CONCLUSIONS

The findings show that varying instructions of the effortful swallow affect hyolaryngeal movement differently, suggesting that clinicians may need to individualize the effortful swallow instruction according to the physiological impairments of each patient. Additionally, natural age-related changes in swallowing physiology do not seem to affect an individual's ability to perform the effortful swallow or to impact hyolaryngeal movement. Finally, the association between tongue pressure and hyolaryngeal movement during normal swallows and the effortful swallow with tongue emphasis suggests that the tongue plays a critical role in swallowing, priming subsequent swallowing events.

Validation of a Geriatric Bedside Swallowing Screen (GEBS): Protocol of a Prospective Cohort Study

BACKGROUND

Demographic changes will raise the need for specialized care of older patients. Oropharyngeal dysphagia has recently been declared a geriatric syndrome reflecting its multifactorial background. Alongside multimorbidity, sarcopenia, frailty, and disability, swallowing disorders increase with advancing age, with prevalence rates reported to be as high as 44% in acute geriatric hospital settings and 80% in long-term care facilities. Hence, systematic screening of older patients to diagnose dysphagia and initiate treatment is of paramount importance to prevent bolus death, aspiration pneumonia, and malnutrition and improve quality of life. Several screening tools have been evaluated in emergency and stroke units. However, no published dysphagia screening tool has been validated in the hospitalized, older adult population using a gold standard in dysphagia diagnostics as a reference test. The validation of the proposed test is a first step.

OBJECTIVE

The Geriatric Bedside Swallowing Screen (GEBS) study aims to validate a new screening tool developed specifically for older inpatients against an instrumental swallowing evaluation, the flexible endoscopic evaluation of swallowing (FEES), which is considered a gold standard. Primary outcomes to be evaluated are sensitivity and specificity for the GEBS in the detection of dysphagia in a mixed older adult population. The presence of dysphagia will be defined by an instrumental swallowing evaluation (FEES), analyzed by the standardized penetration-aspiration scale.

METHODS

To validate the GEBS, a prospective cohort study will be carried out. Two institutions, an acute geriatric department and a long-term care facility, will aim to recruit a total of 100 patients aged ≥75 years. After giving their informed consent, patients will undergo the full screening protocol described in the GEBS as well as an evaluation of swallowing function using the FEES. Investigators will be blinded to the results of the respective other testing. The analysis of pseudonymized data sets will be done by a third investigator. Outcomes to be considered are sensitivity, specificity, diagnostic odds ratio, positive and negative likelihood quotient, and the reliability of the proposed dysphagia screening tool using the κ coefficient.

RESULTS

Recruitment started in October 2022 and will end in April 2024. Data publication is planned for early 2025.

CONCLUSIONS

If proven to be a valid screening tool for the early detection of dysphagia, further studies including different older adult populations as well as studies to determine the impact of systematic dysphagia screening on parameters, such as rates of aspiration pneumonia or nutritional status, should be planned. Effective screening of dysphagia will lead to earlier detection of patients with impaired swallowing. Those who fail the screening will be referred to speech language pathology for further diagnosis, thus optimizing care while streamlining personnel resources.

TRIAL REGISTRATION

ISCRTN Registry ISRCTN11581931; https://www.isrctn.com/ISRCTN11581931.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/46252.

Analysis of swallowing function after anterior/posterior surgery for cervical degenerative disorders and factors related to the occurrence of postoperative dysphagia

BACKGROUND CONTEXT

Dysphagia is one of the postoperative complications of cervical degenerative disorders. However, few studies have evaluated the pre- and postoperative swallowing function in detail.

PURPOSE

To analyze pre- and postoperative swallowing dynamics kinetically and investigate factors associated with postoperative dysphagia in patients with cervical degenerative disorders.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

A total of 41 consecutive patients who underwent an anterior approach (anterior cervical discectomy/corpectomy and fusion (ACDF, ACCF), hybrid surgery (ACDF+ACCF) and total disc replacement) and 44 consecutive patients who underwent a posterior approach (laminoplasty and laminoplasty/laminectomy with fusion).

OUTCOME MEASURES

We compared the pre- and postoperative functional oral intake scale (FOIS), dysphagia severity scale (DSS), esophageal dysphagia, anterior/superior hyoid movement, upper esophageal sphincter (UES) opening, pharyngeal transit time, bolus residue scale (BRS), and the number of swallows.

METHODS

Videofluoroscopy was performed on the day before surgery and within two weeks after surgery. Data related to age, gender, disease, surgical procedure, surgical site, operative time, and blood loss were collected from the medical records. Pre- and postoperative data were compared for each item in the anterior and posterior approaches. The odds ratio of dysphagia after an anterior approach was also calculated.

RESULTS

In the anterior approach, DSS, FOIS, the anterior and superior hyoid movements, maximum UES opening, BRS, and number of swallows worsened postoperatively (p<.05, respectively). In the posterior approach, DSS, FOIS, the anterior hyoid movement, and BRS worsened postoperatively (p<.05, respectively). The factors associated with dysphagia were a proximal surgical site above C3 (OR: 14.40, CI: 2.84-73.02), blood loss >100 mL (OR: 9.60, CI: 2.06-44.74), an operative time >200 minutes (OR: 8.18, CI: 1.51-44.49), and an extensive surgical field of more than three intervertebral levels (OR: 6.72, CI: 1.50-30.07). The decline in swallowing function after the posterior approach was related to aging (p=.045).

CONCLUSIONS

Each approach may decrease swallowing function, especially because of the limitation on the anterior hyoid movement. Dysphagia after anterior approaches was associated with the operative site, operative time, and blood loss.

The Influence of Sex, Age, and Repeated Measurement on Pixel-Based Measures of Pharyngeal Area at Rest

PURPOSE

Videofluoroscopic (VFSS) measurements of pharyngeal swallow mechanics can differentiate age- and disease-related changes in swallowing. Pharyngeal area at rest (PhAR) may differ in people with dysphagia, although its impact is not clear. Before the role of PhAR in dysphagia can be explored, it is important to establish whether PhAR remains stable across repeated measures in healthy adults, and varies as a function of sex or age. We hypothesized that healthy adults would show stable PhAR across repeated measures, but that larger PhAR would be seen in men versus women and in older versus younger adults.

METHOD

We collected VFSS data from 87 healthy adults (44 men, M age = 46 years, range: 21-82). Trained raters identified the swallow rest frame after the initial swallow of each bolus and measured unobliterated pharyngeal area on these frames, in %(C2-4)2 units. Repeated-measures analyses of variance with a factor of sex, a covariate of age, and a repeated factor of task repetition were performed across the first 12 available measures per participant (N = 1,044 swallows).

RESULTS

There were no significant variations in PhAR across repeated measures. A significant Sex × Age interaction was seen (p = .04): Males had significantly larger PhAR than females (p = .001), but females showed larger PhAR with advancing age (R = .47).

CONCLUSIONS

These data confirm stability in PhAR across repeated measurements in healthy individuals. However, significant sex and age differences should be taken into consideration in future studies exploring the role of PhAR in people with dysphagia.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22043543.

Cervical Vertebral Height Approximates Hyoid Displacement in Videofluoroscopic Images of Healthy Adults

Clinicians and researchers commonly judge the completeness of hyoid displacement from videofluoroscopic swallow study (VFSS) videos. Judgments made during the clinical exam are often subjective, and post-examination analysis reduces the measure's immediate value. This study aimed to determine the validity and feasibility of a visual, anatomically scaled benchmark for judging complete hyoid displacement during a VFSS. The third and fourth cervical vertebral bodies (C3 and C4) lie at roughly the same vertical position as the hyoid body and are strongly correlated with patient height. We hypothesized that anterior and superior displacement of the hyoid bone would approximate the height of one C3 or C4 body during safe swallows. Trained raters marked points of interest on C3, C4, and the hyoid body on 1414 swallows of adult patients with suspected dysphagia (n = 195) and 50 swallows of age-matched healthy participants (n = 17), and rated Penetration Aspiration Scale scores. Results indicated that the mean displacements of the hyoid bone were greater than one C3 unit in the superior direction for all swallows from patient and healthy participants, though significantly and clinically greater in healthy participant swallows (p < .001, d > .8). The mean anterior and superior displacements from patient and healthy participant swallows were greater than one C4 unit. Results show preliminary evidence that use of the C3 and/or C4 anatomic scalars can add interpretive value to the immediate judgment of hyoid displacement during the conduct of a clinical VFSS examination.

Jaw-retraction exercise increases anterior hyoid excursion during swallowing in older adults with mild dysphagia

OBJECTIVES

The present study aimed to evaluate the effectiveness of a newly designed jaw-retraction exercise for strengthening the geniohyoid muscle and thus improving the anterior movement of the hyoid bone during swallowing.

BACKGROUND

Although previous studies suggest a relationship between anterior hyoid excursion and upper esophageal sphincter (UES) opening, there are currently no reports of physical exercises without the use of special equipment that can effectively improve this movement of the hyoid bone during swallowing.

MATERIALS AND METHODS

This before-after study included patients presenting to the authors' hospital with mild dysphagia (Level 5 on the Dysphagia Outcome and Severity Scale). The participants were instructed to perform a jaw-retraction exercise designed to strengthen the geniohyoid muscle. Each participant was instructed to perform two sets of the exercise daily for four weeks, with each set consisting of five repetitions. Before and after the four-week training period, videofluoroscopic swallowing studies were performed and later analysed.

RESULTS

Twenty-five patients with a median age of 77 were included. The median peak anterior hyoid position before and after exercise were 129.82 and 132.74 (%C2-C4 length), respectively, and this increase was found to be significant (P = .007). The median extent of UES opening before and after exercise were 8.6 and 9.3 (mm), respectively, and this increase was also found to be significant (P = .040).

CONCLUSION

Our findings demonstrate that the jaw-retraction exercise can effectively improve the anterior movement of the hyoid bone. This exercise may be effective in individuals with oral frailty when signs of swallowing disorders are observed.

Characterizing Swallows From People With Neurodegenerative Diseases Using High-Resolution Cervical Auscultation Signals and Temporal and Spatial Swallow Kinematic Measurements

Purpose The prevalence of dysphagia in patients with neurodegenerative diseases (ND) is alarmingly high and frequently results in morbidity and accelerated mortality due to subsequent adverse events (e.g., aspiration pneumonia). Swallowing in patients with ND should be continuously monitored due to the progressive disease nature. Access to instrumental swallow evaluations can be challenging, and limited studies have quantified changes in temporal/spatial swallow kinematic measures in patients with ND. High-resolution cervical auscultation (HRCA), a dysphagia screening method, has accurately differentiated between safe and unsafe swallows, identified swallow kinematic events (e.g., laryngeal vestibule closure [LVC]), and classified swallows between healthy adults and patients with ND. This study aimed to (a) compare temporal/spatial swallow kinematic measures between patients with ND and healthy adults and (b) investigate HRCA's ability to annotate swallow kinematic events in patients with ND. We hypothesized there would be significant differences in temporal/spatial swallow measurements between groups and that HRCA would accurately annotate swallow kinematic events in patients with ND. Method Participants underwent videofluoroscopic swallowing studies with concurrent HRCA. We used linear mixed models to compare temporal/spatial swallow measurements (n = 170 ND patient swallows, n = 171 healthy adult swallows) and deep learning machine-learning algorithms to annotate specific temporal and spatial kinematic events in swallows from patients with ND. Results Differences (p < .05) were found between groups for several temporal and spatial swallow kinematic measures. HRCA signal features were used as input to machine-learning algorithms and annotated upper esophageal sphincter (UES) opening, UES closure, LVC, laryngeal vestibule reopening, and hyoid bone displacement with 66.25%, 85%, 68.18%, 70.45%, and 44.6% accuracy, respectively, compared to human judges' measurements. Conclusion This study demonstrates HRCA's potential in characterizing swallow function in patients with ND and other patient populations.

Which Physiological Swallowing Parameters Change with Healthy Aging?

Research suggests there are age-related changes in swallowing that do not constitute impairment ("presbyphagia"). The goal of this study was to explore the influence of age on quantitative measures of healthy swallowing by controlling for the effects of sex and sip volume in order to determine the specific characteristics of presbyphagia. Videofluoroscopy recordings of thin liquid swallows from 76 healthy adults (38 male), aged 21-82 were analysed. Blinded duplicate ratings of swallowing safety, efficiency, kinematics, and timing were made using the ASPEKT method. Hierarchical regression models were used to determine the effects of age, sex, and sip-volume on swallowing. There were no age-related changes in sip volume, number of swallows per bolus, frequency or severity of penetration-aspiration, duration of the hyoid-burst (HYB)-to-upper-esophageal-sphincter (UES) opening interval, time-to-laryngeal-vestibule-closure (LVC), peak hyoid position, hyoid speed, or pharyngeal residue. Significant changes seen with increasing age included: longer swallow reaction time, UES opening duration and LVC duration; larger pharyngeal area at rest and maximum constriction; and wider UES diameter. Male participants had larger sip volume and pharyngeal area at rest. Larger sip volumes were associated with multiple swallows per bolus and shorter hyoid-burst-to-UES opening intervals. These results help to define presbyphagic changes in swallowing that can be expected in healthy older adults up to 80 years of age, and distinguish them from changes that represent impairment. Certain parameters showed changes that were opposite in direction to changes that are usually considered to reflect impairment: longer UES opening, longer LVC duration and wider UES opening. These changes may reflect possible compensations for slower bolus transit. Further research is needed to determine the points along the age continuum where observed age-related changes in swallowing begin to emerge.

Variations in Hyoid Kinematics Across Liquid Consistencies in Healthy Swallowing

Purpose Judgments regarding hyoid movement are frequently included in evaluations of swallowing. However, the literature lacks reference values for measures of hyoid kinematics in healthy swallowing. This study explores hyoid movement across the continuum from thin to extremely thick liquids. Method Participants were 39 healthy adults under the age of 60 years (19 men) who underwent videofluoroscopy involving three sips each of 20% w/v thin barium and six sips each of slightly, mildly, moderately, and extremely thick barium. Half of the thickened stimuli were prepared using xanthan gum; and half, with a starch-based thickener. Sip volume was derived from pre- and post-sip cup weights. Hyoid position was tracked frame-by-frame relative to the anterior-inferior corner of C4. Measures of peak hyoid position (along the XY axis) were normalized to a C2-C4 scalar, and measures of time-to-peak position, speed, and time-to-peak speed were derived. As a first step, Spearman's correlations confirmed the influence of sip volume on these hyoid measures. Linear mixed-effects models then explored the effects of stimulus, sip volume, and task repetition on the dependent variables. Results The data set comprised 975 swallows with available hyoid tracking data. Sip volume was correlated with peak hyoid XY position (rs = .15, p < .01), time-to-peak position (rs = -.15, p < .05), and speed (rs = .13, p < .01). No significant differences in hyoid kinematics were found across stimuli. Conclusion Measures of hyoid movement in healthy swallowing remain stable across the range from thin to extremely thick liquids with no systematic alterations in hyoid position or kinematics.

Determining the Underlying Relationship Between Swallowing and Maximum Vocal Pitch Elevation: A Preliminary Study of Their Hyoid Biomechanics in Healthy Adults

Purpose Deficiencies in swallowing (aspiration) and in maximum vocal pitch elevation have been shown to correlate in dysphagia. However, the underlying mechanisms that may explain this relationship are not known. In this study, we compare hyoid kinematics between swallowing and maximum vocal pitch elevation in healthy adults. Method Ten young (M = 21 ± 1.33 years) and eight older (M = 72.85 ± 5.59 years) healthy adults completed trials of maximum vocal pitch elevation (vowels /a/ and /i/) and swallowing (thin liquid and pudding) under videofluoroscopy. Superior and anterior hyoid excursions were obtained using kinematic analysis. Two-way analyses of variance and Spearman rho correlations were used to examine differences and relationships between swallowing and maximum pitch elevation biomechanics. Results Superior hyoid excursion was significantly greater for liquid swallows compared to pitch elevation tasks (/a/ and /i/; p = .002; Cohen's d = 1.28; p = .0179, Cohen's d = 1.03, respectively) and for pudding swallows compared to pitch tasks (p = .000, Cohen's d = 1.64; p = .001, Cohen's d = 1.38, respectively). Anterior hyoid excursion was not significantly different between the two functions, but was overall reduced in the older group (p = .0231, Cohen's d = .90). Furthermore, there was a moderate positive correlation between the degree of superior excursion during liquid swallows and maximum pitch elevation for both vowels (r s = .601, p = .001; r s = .524, p = .003) in young adults, and between the degree of anterior excursion during liquid swallows and pitch elevation for both vowels (r s = .688, p = .001; r s = .530, p = .008) in older adults. Conclusions Swallowing and maximum pitch elevation require similar anterior, but not superior, hyoid excursion in healthy adults. Differential correlations between the two tasks for each age group may be associated with age-related muscle changes. We provide evidence of partially shared biomechanics between swallowing and maximum pitch elevation.

Establishing a method for quantifying spinal curvature during videofluoroscopic swallow studies: Applying the modified Cobb angle to healthy young and older adults

The Cobb angle is traditionally used for quantifying the degree of spinal curvature through evaluation of the full spinal cord. When conducting measurements on videofluoroscopy swallowing studies (VFSS), the Cobb angle can measure degree of cervical vertebrae curvature, which may have implications for swallowing. Given that this measure may have utility in dysphagia research, the reliability of this measure taken from C2-C4 and establishing the presence of changes with age were the focus of the current, proof-of-principle study. VFSS from 19 healthy young adults and 39 healthy older adults were retrospectively analyzed. The C2-C4 Cobb angle was measured between cervical vertebrae two and four on frames of laryngeal vestibule closure (LVC) and post-swallow rest. Results revealed excellent levels of inter- and intra-rater reliability for frame of post-swallow rest (ICCs = 0.788 and 0.793), and fair to good levels of agreement for frame of LVC (ICCs = 0.667 and 0.621). Significant differences in the C2-C4 Cobb angle were found between the healthy young and old data (p < 0.01). Healthy younger adults had a mean angle of 5.8±9.0 degrees at LVC and 7.7±4.5 degrees at swallow rest, whereas healthy older adults had a mean angle of 12.5±9.0 degrees at LVC and 12.4±9.7 degrees at rest. Consistent with the existing spine literature, the curvature of cervical vertebrae appears to increase with age. With established reliability, we propose that the C2-C4 Cobb angle may be used to determine the degree of spinal curvature in a variety of patient populations in order to determine impacts on swallowing function.