Autonomic Recalibration: A Promising Approach for Alleviating Myofascial Pain Explored in a Retrospective Case Series.

This retrospective case series introduces autonomic recalibration (AR) as a novel approach for alleviating chronic myofascial pain. The manuscript explores the rationale, theory, and practice of AR, which targets the autonomic nervous system (ANS) to restore homeostasis and reduce pain. The involvement of the ANS in pain modulation and the role of autonomic imbalance in chronic pain are discussed, emphasizing the potential benefits of addressing autonomic dysregulation through AR. The technique combines manual interventions and patient education, relying on neuroplastic adaptations. Three diverse case reports are presented to illustrate the effectiveness of AR in patients with different sources of pain. Each case presents a unique clinical scenario, including a nine-year-old male diagnosed with spondylolisthesis, a 68-year-old male with a history of abdominal surgeries, and a 56-year-old male with chronic low back pain following lumbar fusion surgery. In all cases, AR resulted in pain relief, improved sleep, and restoration of functional abilities. These findings support the potential of AR as an effective alternative approach for myofascial pain. Further research is warranted to validate these outcomes and investigate the underlying mechanisms of AR.

Clinical shadowing experience PIF rubric.

BACKGROUND: The purpose of this study was to develop and evaluate a tool for documenting professional identity formation (PIF) among preclinical medical students, via reflective writings (RWs) about their clinical shadowing experiences. APPROACH: To address our key questions, stakeholders conducted comprehensive literature analysis, and the authors developed an analytic rubric through an iterative immersion/crystallisation process. EVALUATION: Rubric iterations were empirically tested, assessed for interrater reliability, refined and then applied in successive development phases to medical student RW narratives. Twenty-nine first-year RWs on their shadowing experiences were included for this developmental evaluation. IMPLICATIONS: The clinical shadowing experience PIF rubric is a theory-informed analytic tool that demonstrates feasibility of measuring PIF in preclinical medical students' RWs. Reliable use of this tool currently requires a team approach that could be improved by machine learning.

Pilot Study of Quantitative Methods for Differentiating Pharyngeal Swallowing Mechanics by Dysphagia Etiology.

Quantitative analysis of modified barium swallow (MBS) imaging is useful to determine the impact of various disease states on pharyngeal swallowing mechanics. In this retrospective proof of concept study, kinematic analysis and computational analysis of swallowing mechanics (CASM) were used to demonstrate how these methods differentiate swallowing dysfunction by dysphagia etiology. Ten subjects were randomly selected from four cohorts of dysphagic patients including COPD, head and neck cancer (HNC), motor neuron disease, and stroke. Each subject was age- and gender-matched with healthy, non-dysphagic controls. MBS videos of 5 ml thin and 5 ml thick bolus trials from each subject were used. A MATLAB tracker tool was adapted and updated to collect and compile data for each video (n = 160). For kinematic measurements, a MANOVA was performed with post-hoc analyses to determine group differences. For CASM measurements, a morphometric canonical variate analysis with post hoc analysis was performed to determine group differences. Kinematic analyses indicated statistically significant differences between HNC cohort and controls in distance measurements for hyolaryngeal approximation (p = .001), laryngeal elevation (p = 0.0001), pharyngeal shortening (p = 0.0002), and stage transition duration timing (p = 0.002). Timing differences were noted between the stroke cohort and controls for pharyngeal transit time (p = 0.007). Multivariate morphometric canonical variate analysis showed significant differences between etiology groups (p < 0.0001) with eigenvectors indicating differing patterns of swallowing mechanics. This study demonstrated that swallowing mechanics among cohorts of dysphagic patients can be differentiated using kinematics and CASM, providing different but complementary quantitative methods for investigating the impact of various disease states on swallowing function.

What does it mean to be a physician? Exploring social imaginaries of first-year medical students.

OBJECTIVES: To explore if community embedded discussions with local community members reshape the social imaginary of medicine among students and contribute positively to their professional identity. METHODS: This explorative, qualitative study involved 35 first-year medical students who volunteered to attend a 2-hour forum at a local church to ask community members about their experiences with doctors and healthcare systems.  Student participants were asked to reflect on five structured questions. The written reflections were submitted for analysis, de-identified, and analyzed using Glaser's classic grounded theory, constant comparative analysis, and Taylor's model of modern social imaginaries as an analytical lens. RESULTS: The results indicate that student participants identified seven main themes regarding what community members expect from their doctors, including active listening (n=22), physical touch (n=18), and compassion (n=16). Responses also indicated that only 5.6% of the students felt that the preclinical curriculum was adequately preparing them for what local community members identified as important to patient care. However, students recognized that two aspects of the curriculum, Physical Diagnosis (n=12) and volunteering/community engagement (n=9), were congruent with the expectations of future patients. CONCLUSIONS: The results suggest that students identified educational experiences that were congruent with the social imaginary of patients. However, patient expectations were discordant to some aspects of the medical imaginary of medical students. The experience and subsequent reflections may be salient to contributing to each student's professional identity and provide a model for other medical schools to explore how the curriculum is fulfilling the community's perception of ideal patient care.

Variations in Healthy Swallowing Mechanics During Various Bolus Conditions Using Computational Analysis of Swallowing Mechanics (CASM).

Bolus properties such as volume, consistency, and density have been shown to influence swallowing through the analysis of kinematics and timing in both normal and disordered swallowing. However, inherent intra- and inter-person variability of swallowing cloud interpretation of group data. Computational analysis of swallow mechanics (CASM) is an established methodology that uses coordinate tracking to map structural movements during swallowing and yields statistically powerful analyses at both the group and individual levels. In this study, the CASM method was used to determine how different bolus properties (volume, consistency, and density) altered swallow mechanics in healthy young adults at the group and individual levels. Videofluoroscopic swallow studies of 10 (4 females) healthy young adults were analyzed using CASM. Five bolus types were administered in each study (3 × 5 ml 40% w/v nectar, 3 × 5 ml 22% w/v thin, 3 × 5 ml 40% w/v thin, 3 × 10 ml 22% w/v thin, and 3 × 20 ml 22% w/v thin). Canonical variate analyses demonstrated that bolus condition did not affect swallowing mechanics at the group level, but bolus condition did affect pharyngeal swallow mechanics at the individual level. Functional swallow adaptations (e.g., hyoid movement) to bolus conditions were not uniform across participants, consistent with the nonsignificant group finding. These results suggest that individual swallowing systems of healthy young individuals vary in how they respond to bolus different conditions, highlighting the intrinsic variability of the swallow mechanism and the importance of individually tailored evaluation and treatment of swallowing. Findings warrant further investigation with different bolus conditions and aging and disordered populations.

Pharyngeal swallowing mechanics associated with upper esophageal sphincter pressure wave.

BACKGROUND: Opening of the upper esophageal sphincter (UES) is a critical element of swallowing. Understanding the functional pharyngeal anatomy during UES opening would be clinically useful for dysphagia evaluation and treatment. METHODS: Simultaneous high-resolution pharyngeal manometry and videofluoroscopy (VFS) videos for 18 nondysphagic subjects were evaluated. UES pressure readings were segmented into six pressure phases, including a poorly understood pre-relaxation contraction. Anatomic landmarks were tracked in VFS imaging and evaluated morphometrically to determine the movement of key swallowing structures within each UES pressure phase. RESULTS: There were significant differences in pharyngeal mechanics by UES pressure stage (range of D-values = 1.7-2.2, P < .0001). The soft palate maximally elevates during the pre-relaxation contraction of the UES. Early during UES relaxation, the hyolaryngeal complex and pharyngeal structures maximally elevate and pharyngeal structures constrict around the bolus. CONCLUSION: The mechanics underlying the UES pressure wave suggest generation of a sealed pharyngeal cavity, possibly integral to pharyngeal pressure generation and bolus propulsion.

Taste Manipulation and Swallowing Mechanics in Trauma-Related Sensory-Based Dysphagia.

Purpose This study explored the effects of high-concentration taste manipulation trials on swallow function in persons with sensory-based dysphagia. Method Dysphagia researchers partnered with clinical providers to prospectively identify traumatically injured U.S. military service members (N = 18) with sensory-based dysphagia as evidenced by delayed initiation and/or decreased awareness of residue/penetration/aspiration. Under videofluoroscopy, participants swallowed trials of 3 custom-mixed taste stimuli: unflavored (40% weight/volume [wt/vol] barium sulfate in distilled water), sour (2.7% wt/vol citric acid in 40% wt/vol barium suspension), and sweet-sour (1.11% wt/vol citric acid plus 8% wt/vol sucrose in 40% wt/vol barium suspension). Trials were analyzed and compared via clinical rating tools (the Modified Barium Swallow Impairment Profile [Martin-Harris et al., 2008] and the Penetration-Aspiration Scale [Rosenbek, Robbins, Roecker, Coyle, & Wood, 1996]). Additionally, a computational analysis of swallowing mechanics (CASM) was applied to a subset of 9 swallows representing all 3 tastants from 3 participants. Results Friedman's tests for the 3 stimuli revealed significantly (p < .05) improved functional ratings for Penetration-Aspiration Scale and pharyngoesophageal opening. CASM indicated differences in pharyngeal swallowing mechanics across all tastant comparisons (p ≤ .0001). Eigenvectors revealed increased tongue base retraction, hyoid elevation, and pharyngeal shortening for sweet-sour and, to a lesser extent, sour than for unflavored boluses. Conclusion Advantageous changes in certain parameters of oropharyngeal swallowing physiology were noted with high-intensity tastants per both clinical ratings and subsequent CASM, suggesting potential therapeutic application for taste manipulation.

Functional Modules of Pharyngeal Swallowing Mechanics.

OBJECTIVES: The present retrospective cohort study aims to test the hypothesis that elements of swallowing mechanics including hyoid movement, laryngeal elevation, tongue base retraction, pharyngeal shortening, pharyngeal constriction, and head and neck extension can be grouped into functional modules, and that these modules are predictably altered in disease states. METHODS: Modified barium swallow video clips of a thick and a thin liquid swallow from 40 normal patients and 10 dysphagic post-treatment oropharyngeal head-and-neck cancer (HNC) patients were used in this study. Coordinate locations of 12 anatomical landmarks mapping pharyngeal swallowing mechanics were tracked on every frame during the pharyngeal phase of each swallow using a custom-made MATLAB tool. Morphometric modularity hypothesis testing was performed on these coordinate data to characterize the modular elements of swallowing function in each cohort using MorphoJ software. RESULTS: The elements of normal swallowing can be grouped into four functional modules including bolus propulsion, pharyngeal shortening, airway protection, and head and neck posture. Modularity in HNC patient showed an intact airway protection module but altered bolus propulsion and pharyngeal shortening modules. To cross-validate the alteration in modules, a post hoc analysis was performed, which showed significantly increased vallecular (P < .04) and piriform (P < .05) residue but no significant change in aspiration status in the HNC cohort versus controls. CONCLUSIONS: This study suggests that while pharyngeal swallowing mechanics is highly complex, the system is organized into functional modules, and that changes in modularity impacts swallowing performance. This approach to understanding swallowing function may help the patient care team better address swallowing difficulties. LEVEL OF EVIDENCE: 2b.

Intravelar and Extravelar Portions of Soft Palate Muscles in Velic Constrictions: A Three-Dimensional Modeling Study.

Purpose This study predicts and simulates the function and relative contributions of the intravelar and extravelar portions of the levator veli palatini (LVP) and palatoglossus (PG) muscles in velic constrictions. Method A finite element-based model of the 3-dimensional upper airway structures (palate, pharynx, tongue, jaw, maxilla) was implemented, with LVP and PG divided into intravelar and extravelar portions. Simulations were run to investigate the contributions of these muscles in velopharyngeal port (VPP) closure and constriction of the oropharyngeal isthmus (OPI). Results Simulations reveal that the extravelar portion of LVP, though crucial for lifting the palate, is not sufficient to effect VPP closure. Specifically, the characteristic "bulge" appearing in the posterior soft palate during VPP closure ( Pigott, 1969 ; Serrurier & Badin, 2008 ) is found to result from activation of the intravelar portion of LVP. Likewise, the intravelar portion of posterior PG is crucial in bending the "veil" or "traverse" ( Gick, Francis, Klenin, Mizrahi, & Tom, 2013 ) of the velum anteriorly to produce uvular constrictions of the OPI ( Gick et al., 2014 ). Conclusions Simulations support the view that intravelar LVP and PG play significant roles in VPP and OPI constrictions.

Genetic Taster Status as a Mediator of Neural Activity and Swallowing Mechanics in Healthy Adults.

As part of a larger study examining relationships between taste properties and swallowing, we assessed the influence of genetic taster status (GTS) on measures of brain activity and swallowing physiology during taste stimulation in healthy men and women. Twenty-one participants underwent videofluoroscopic swallowing study (VFSS) and functional magnetic resonance imaging (fMRI) during trials of high-intensity taste stimuli. The precisely formulated mixtures included sour, sweet-sour, lemon, and orange taste profiles and unflavored controls. Swallowing physiology was characterized via computational analysis of swallowing mechanics plus other kinematic and temporal measures, all extracted from VFSS recordings. Whole-brain analysis of fMRI data assessed blood oxygen responses to neural activity associated with taste stimulation. Swallowing morphometry, kinematics, temporal measures, and neuroimaging analysis revealed differential responses by GTS. Supertasters exhibited increased amplitude of most pharyngeal movements, and decreased activity in the primary somatosensory cortex compared to nontasters and midtasters. These preliminary findings suggest baseline differences in swallowing physiology and the associated neural underpinnings associated with GTS. Given the potential implications for dysphagia risk and recovery patterns, GTS should be included as a relevant variable in future research regarding swallowing function and dysfunction.

Improvements resulting from respiratory-swallow phase training visualized in patient-specific computational analysis of swallowing mechanics.

The aim of this study was to visualize improved swallowing mechanics resulting from respiratory-swallow phase training using patient specific computational analysis of Modified Barium Swallow (MBS) videofluoroscopic images. Imaging from a single subject showing improved MBSImP™© scores in 17 of 18 pre- to post-treatment swallows was selected for analysis. Using a semi-automated MATLAB tracker tool, a frame-by-frame annotation of 10 coordinates mapping muscle functional groups was performed during oropharyngeal swallowing. Computational analysis of coordinate shape change was executed using MorphoJ software to determine differences in swallowing mechanics associated with multiple independent variables. Canonical variant analysis indicated significant differences in mechanics associated with respiratory-swallow phase training (D=1.92,p<.0001). Vectors allowed for visualization of changes in swallowing mechanics associated with respiratory-swallow phase training. A regression of shape associated with laryngeal vestibular closure on respiratory-swallow phase training was highly significant (p<.0001) and accounted for 94.1% of the variance.

Computational analysis of swallowing mechanics after surgery for obstructive sleep apnea.

Multilevel upper airway surgery for obstructive sleep apnea (OSA) has been shown to cause clinically significant dysphagia in some patients. We describe the cases of 2 adults with OSA who developed persistent dysphagia after multilevel upper airway surgery. Patient-specific computational analysis of swallowing mechanics (CASM) revealed absent pharyngeal shortening and aberrant tongue base retraction in both patients. These findings are consistent with the OSA surgical goal of enlarging the hypopharyngeal airway but likely contributed to our patients' dysphagia. Patient-specific CASM allows for sensitive identification of swallowing mechanical dysfunction that might otherwise be overlooked, and it may be utilized in future head and neck surgery patients to analyze swallowing dysfunction associated with treatment.

Differences in swallow physiology in patients with left and right hemispheric strokes.

BACKGROUND: We sought to determine the impact of lesion lateralization and lesion volume on swallow impairment on group-level by comparing patients with left and right hemisphere strokes and on patient-level by analyzing patients individually. METHODS: We performed a retrospective, observational, cross-sectional study of 46 patients with unilateral (22 left, 24 right), acute, first-ever, ischemic strokes who received a diffusion weighted MRI (DW-MRI) and modified barium swallow study (MBSS) during their acute hospital stay. We determined lesion side on the DW-MRI and measured swallow physiology using the Modified Barium Swallow Impairment Profile (MBSImP™©), Penetration-Aspiration Scale (PAS), swallow timing, distance, area, and speed measures. We performed Pearson's Chi-Square and Wilcoxon Rank-Sum tests to compare patients with left and right hemisphere strokes, and Pearson or Spearman correlation, simple logistic regression, linear, and logistic multivariable regression modeling to assess the relationship between variables. RESULTS: At the group-level, there were no differences in MBSImP oral swallow impairment scores between patients with left and right hemisphere stroke. In adjusted analyses, patients with right hemisphere strokes showed significantly worse MBSImP pharyngeal total scores (p = 0.02), worse MBSImP component specific scores for laryngeal vestibular closure (Bonferroni adjusted alpha p ≤ 0.0029), and worse PAS scores (p = 0.03). Patients with right hemisphere strokes showed worse timing, distance, area, and speed measures. Lesion volume was significantly associated with MBSImP pharyngeal residue (p = 0.03) and pharyngeal total scores (p = 0.04). At the patient-level, 24% of patients (4 left, 7 right) showed opposite patterns of MBSImP oral and pharyngeal swallow impairment than seen at group-level. CONCLUSION: Our study showed differences in swallow physiology between patients with right and left unilateral strokes with patients with right hemisphere strokes showing worse pharyngeal impairment. Lesion lateralization seems to be a valuable marker for the severity of swallowing impairment at the group-level but less informative at the patient-level.

Computational Analysis of Pharyngeal Swallowing Mechanics in Patients with Motor Neuron Disease: A Pilot Investigation.

Swallowing impairment (dysphagia) is a common sequela in patients with motor neuron disease (MND). The purpose of this retrospective, observational pilot investigation was to characterize how pharyngeal swallowing mechanics are impacted in patients with MND using a comparison with healthy, non-dysphagic control group. Computational analysis of swallowing mechanics (CASM) was used to determine covariate biomechanics of pharyngeal swallowing from videofluoroscopic assessment in 15 patients with MND and 15 age- and sex-matched healthy controls. Canonical variant analysis with post hoc discriminate function analysis (DFA) was performed on coordinate data mapping functional muscle groups underlying pharyngeal swallowing. Differences in swallowing mechanics associated with group (MND; control), motor neuron predominance (upper; lower), onset (bulbar; spinal), and swallow task (thin, pudding) were evaluated and visualized. Pharyngeal swallowing mechanics differed significantly in patients with MND compared with healthy controls (D = 2.01, p < 0.0001). Post hoc DFA pairwise comparisons suggest differences in pharyngeal swallow mechanics by motor neuron predominance (D = 5.03, p < 0.0001), onset (D = 2.03, p < 0.0001), and swallow task (D = 1.04, p < 0.0001). Pharyngeal swallowing mechanics of patients with MND differ from and are more heterogeneous than healthy controls. These findings suggest patients with MND may compensate reductions in pharyngeal shortening and tongue base retraction by extending the head and neck and increasing hyolaryngeal excursion. This work and further CASM investigations will lead to further insights into development and evaluation of targeted clinical treatments designed to prolong safe and efficient swallowing function in patients with MND.

Swallowing Mechanics Associated With Artificial Airways, Bolus Properties, and Penetration-Aspiration Status in Trauma Patients.

Purpose: Artificial airway procedures such as intubation and tracheotomy are common in the treatment of traumatic injuries, and bolus modifications may be implemented to help manage swallowing disorders. This study assessed artificial airway status, bolus properties (volume and viscosity), and the occurrence of laryngeal penetration and/or aspiration in relation to mechanical features of swallowing. Method: Coordinates of anatomical landmarks were extracted at minimum and maximum hyolaryngeal excursion from 228 videofluoroscopic swallowing studies representing 69 traumatically injured U.S. military service members with dysphagia. Morphometric canonical variate and regression analyses examined associations between swallowing mechanics and bolus properties based on artificial airway and penetration-aspiration status. Results: Significant differences in swallowing mechanics were detected between extubated versus tracheotomized (D = 1.32, p < .0001), extubated versus decannulated (D = 1.74, p < .0001), and decannulated versus tracheotomized (D = 1.24, p < .0001) groups per post hoc discriminant function analysis. Tracheotomy-in-situ and decannulated subgroups exhibited increased head/neck extension and posterior relocation of the larynx. Swallowing mechanics associated with (a) penetration-aspiration status and (b) bolus properties were moderately related for extubated and decannulated subgroups, but not the tracheotomized subgroup, per morphometric regression analysis. Conclusion: Specific differences in swallowing mechanics associated with artificial airway status and certain bolus properties may guide therapeutic intervention in trauma-based dysphagia.

Pharyngeal Swallowing Mechanics Secondary to Hemispheric Stroke.

BACKGROUND: Computational analysis of swallowing mechanics (CASM) is a method that utilizes multivariate shape change analysis to uncover covariant elements of pharyngeal swallowing mechanics associated with impairment using videofluoroscopic swallowing studies. The goals of this preliminary study were to (1) characterize swallowing mechanics underlying stroke-related dysphagia, (2) decipher the impact of left and right hemispheric strokes on pharyngeal swallowing mechanics, and (3) determine pharyngeal swallowing mechanics associated with penetration-aspiration status. METHODS: Videofluoroscopic swallowing studies of 18 dysphagic patients with hemispheric infarcts and age- and gender-matched controls were selected from well-controlled data sets. Patient data including laterality and penetration-aspiration status were collected. Coordinates mapping muscle group action during swallowing were collected from videos. Multivariate morphometric analyses of coordinates associated with stroke, affected hemisphere, and penetration-aspiration status were performed. RESULTS: Pharyngeal swallowing mechanics differed significantly in the following comparisons: stroke versus controls (D = 2.19, P < .0001), right hemispheric stroke versus controls (D = 3.64, P < .0001), left hemispheric stroke versus controls (D = 2.06, P < .0001), right hemispheric stroke versus left hemispheric stroke (D = 2.89, P < .0001), and penetration-aspiration versus within normal limits (D = 2.25, P < .0001). Differences in pharyngeal swallowing mechanics associated with each comparison were visualized using eigenvectors. CONCLUSIONS: Whereas current literature focuses on timing changes in stroke-related dysphagia, these data suggest that mechanical changes are also functionally important. Pharyngeal swallowing mechanics differed by the affected hemisphere and the penetration-aspiration status. CASM can be used to identify patient-specific swallowing impairment associated with stroke injury that could help guide rehabilitation strategies to improve swallowing outcomes.

Computational analysis of swallowing mechanics underlying impaired epiglottic inversion.

OBJECTIVES/HYPOTHESIS: Determine swallowing mechanics associated with the first and second epiglottic movements, that is, movement to horizontal and full inversion, respectively, to provide a clinical interpretation of impaired epiglottic function. STUDY DESIGN: Retrospective cohort study. METHODS: A heterogeneous cohort of patients with swallowing difficulties was identified (n = 92). Two speech-language pathologists reviewed 5-mL thin and 5-mL pudding videofluoroscopic swallow studies per subject, and assigned epiglottic component scores of 0 = complete inversion, 1 = partial inversion, and 2 = no inversion, forming three groups of videos for comparison. Coordinates mapping minimum and maximum excursion of the hyoid, pharynx, larynx, and tongue base during pharyngeal swallowing were recorded using ImageJ software. A canonical variate analysis with post hoc discriminant function analysis of coordinates was performed using MorphoJ software to evaluate mechanical differences between groups. Eigenvectors characterizing swallowing mechanics underlying impaired epiglottic movements were visualized. RESULTS: Nineteen of 184 video swallows were rejected for poor quality (n = 165). A Goodman-Kruskal index of predictive association showed no correlation between epiglottic component scores and etiologies of dysphagia (λ = .04). A two-way analysis of variance by epiglottic component scores showed no significant interaction effects between sex and age (f = 1.4, P = .25). Discriminant function analysis demonstrated statistically significant mechanical differences between epiglottic component scores: 1 and 2, representing the first epiglottic movement (Mahalanobis distance = 1.13, P = .0007); and 0 and 1, representing the second epiglottic movement (Mahalanobis distance = 0.83, P = .003). Eigenvectors indicate that laryngeal elevation and tongue base retraction underlie both epiglottic movements. CONCLUSIONS: Results suggest that reduced tongue base retraction and laryngeal elevation underlie impaired first and second epiglottic movements. The styloglossus, hyoglossus, and long pharyngeal muscles are implicated as targets for rehabilitation in dysphagic patients with impaired epiglottic inversion. LEVEL OF EVIDENCE: 2b Laryngoscope, 126:1854-1858, 2016.

Impaired swallowing mechanics of post radiation therapy head and neck cancer patients: A retrospective videofluoroscopic study.

AIM: To determine swallowing outcomes and hyolaryngeal mechanics associated with post radiation therapy head and neck cancer (rtHNC) patients using videofluoroscopic swallow studies. METHODS: In this retrospective cohort study, videofluoroscopic images of rtHNC patients (n = 21) were compared with age and gender matched controls (n = 21). Penetration-aspiration of the bolus and bolus residue were measured as swallowing outcome variables. Timing and displacement measurements of the anterior and posterior muscular slings elevating the hyolaryngeal complex were acquired. Coordinate data of anatomical landmarks mapping the action of the anterior muscles (suprahyoid muscles) and posterior muscles (long pharyngeal muscles) were used to calculate the distance measurements, and slice numbers were used to calculate time intervals. Canonical variate analysis with post-hoc discriminant function analysis was performed on coordinate data to determine multivariate mechanics of swallowing associated with treatment. Pharyngeal constriction ratio (PCR) was also measured to determine if weak pharyngeal constriction is associated with post radiation therapy. RESULTS: The rtHNC group was characterized by poor swallowing outcomes compared to the control group in regards to: Penetration-aspiration scale (P < 0.0001), normalized residue ratio scale (NRRS) for the valleculae (P = 0.002) and NRRS for the piriform sinuses (P = 0.003). Timing and distance measurements of the anterior muscular sling were not significantly different in the two groups, whereas for the PMS time of displacement was abbreviated (P = 0.002) and distance of excursion was reduced (P = 0.02) in the rtHNC group. A canonical variate analysis shows a significant reduction in pharyngeal mechanics in the rtHNC group (P < 0.0001). The PCR was significantly higher in the test group than the control group (P = 0.0001) indicating reduced efficiency in pharyngeal clearance. CONCLUSION: Using videofluoroscopy, this study shows rtHNC patients have worse swallowing outcomes associated with reduced hyolaryngeal mechanics and pharyngeal constriction compared with controls.

Evaluating muscles underlying tongue base retraction in deglutition using muscular functional magnetic resonance imaging (mfMRI).

PURPOSE: Tongue base retraction during swallowing is critical to bolus propulsion in normal physiological swallowing. A better understanding of the hyoglossus and styloglossus, muscles thought to be key to tongue base retraction, will improve the quality of physical rehabilitation in dysphagic patients in addition to preventing iatrogenic damage to structures critical to deglutition. This study utilized muscle functional MRI in healthy adult human subjects in order to determine if the hyoglossus and styloglossus are active during swallowing. METHODS AND MATERIALS: Data were collected for 11 subjects with mfMRI before and after swallowing, and after performing the Mendelsohn maneuver. Whole muscle relaxation time profiles (T2 signal in milliseconds) were calculated from weighted averages of multiple dual echo MRI slices, allowing for comparison of physiological response for the muscles in each test condition. Changes in effect size (Cohen's d) of whole muscle T2 profiles were used to establish whether or not the hyoglossus and styloglossus are utilized during swallowing and during the Mendelsohn maneuver. RESULTS: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity) for the T2 signal profiles of the hyoglossus and styloglossus were found to be d=1.19 and 0.22, respectively. The hyoglossus showed an effect size change of d=0.26 for the Mendelsohn maneuver. CONCLUSIONS: Muscle functional MRI indicates a physiological response of the hyoglossus and styloglossus during swallowing, and the hyoglossus during the Mendelsohn maneuver.

Effects of non-invasive brain stimulation on post-stroke dysphagia: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: The primary aim of this review is to evaluate the effects of non-invasive brain stimulation on post-stroke dysphagia. METHODS: Thirteen databases were systematically searched through July 2014. Studies had to meet pre-specified inclusion and exclusion criteria. Each study's methodological quality was examined. Effect sizes were calculated from extracted data and combined for an overall summary statistic. RESULTS: Eight randomized controlled trials were included. These trials revealed a significant, moderate pooled effect size (0.55; 95% CI=0.17, 0.93; p=0.004). Studies stimulating the affected hemisphere had a combined effect size of 0.46 (95% CI=-0.18, 1.11; p=0.16); studies stimulating the unaffected hemisphere had a combined effect size of 0.65 (95% CI=0.14, 1.16; p=0.01). At long-term follow up, three studies demonstrated a large but non-significant pooled effect size (0.81, p=0.11). CONCLUSIONS: This review found evidence for the efficacy of non-invasive brain stimulation on post-stroke dysphagia. A significant effect size resulted when stimulating the unaffected rather than the affected hemisphere. This finding is in agreement with previous studies implicating the plasticity of cortical neurons in the unaffected hemisphere. SIGNIFICANCE: Non-invasive brain stimulation appears to assist cortical reorganization in post-stroke dysphagia but emerging factors highlight the need for more data.