Examination of swallowing maneuver training and transfer of practiced behaviors to laryngeal vestibule kinematics in functional swallowing of healthy adults

Impact of Varying Transcutaneous Electrical Stimulation Pulse Frequency on Swallow Timing Measures in Healthy Adults

The impaired swallow timing subsequent to dysphagia or aging can potentially endanger swallowing safety and efficiency. Preliminary evidence has suggested that transcutaneous electrical stimulation (TES) may have the potential to affect swallow timing. However, limited knowledge exists regarding which TES parameters can optimize swallow timing. Pulse frequency is one of the primary TES parameters that can affect the quality of muscle contraction. Yet, no clear information exists regarding how changing pulse frequency impacts the timing of swallowing events. This study aimed to investigate the varying effects of submental TES pulse frequency on swallowing events during and post-15-min TES administration. Twenty-six healthy individuals between the ages of 20 and 54 participated in this study and were assigned to high pulse frequency (HPF) (80 Hz) or low pulse frequency (LPF) (30 Hz) groups. Videofluoroscopic swallowing study (VFSS) was used to record swallowing. Three trials of 10 mL pureed mixed with barium sulfate were presented under three different conditions, including pre-TES, during TES, and post-TES, in which measures were taken following 15 min of TES delivery. The swallow timing events that were measured in each condition were time to maximum hyoid elevation, time to maximum laryngeal elevation, laryngeal vestibule closure reaction time (LVCrt), laryngeal vestibule closure duration (LVCd), time to maximum pharyngeal constriction, and pharyngoesophageal segment (PES) opening duration. No significant pulse frequency effect was found on any swallow timing measures during or after 15 min of TES. Both protocols decreased the duration of some swallowing events during TES including time to maximum hyoid elevation [p < 0.017, ηp2 = 0.185], LVCrt [p < 0.032, ηp2 = 0.158], and time to maximum pharyngeal constriction [p < 0.034, ηp2 = 0.155]. None of the significant TES effects were continued when TES ceased after 15 min. Overall, both protocols have comparable immediate effects on shortening the duration of some swallowing events during TES. Future clinical trials should examine whether these physiologic timing changes can lead to safer and more efficient swallows in patients with dysphagia.

Quantitative Analysis of Temporal Parameters Correlated with Aspiration and Lesion Location in Stroke Patients

The purpose of this study was to identify differences in temporal parameters correlating to the presence of aspiration and the severity of penetration-aspiration scale (PAS) in patients with dysphagia after stroke. We also investigated whether there was a significant difference in temporal parameters based on the location of the stroke lesion. A total of 91 patient videofluoroscopic swallowing study (VFSS) videos of stroke patients with dysphagia were retrospectively analyzed. Various temporal parameters including oral phase duration, pharyngeal delay time, pharyngeal response time, pharyngeal transit time, laryngeal vestibule closure reaction time, laryngeal vestibule closure duration, upper esophageal sphincter opening duration and upper esophageal sphincter reaction time were measured. Subjects were grouped by the presence of aspiration, PAS score, and location of the stroke lesion. Pharyngeal response time, laryngeal vestibule closure duration, and upper esophageal sphincter opening duration were significantly prolonged in the aspiration group. These three factors showed positive correlation with PAS. In terms of stroke lesion, oral phase duration was significantly prolonged in the supratentorial lesion group, while upper esophageal sphincter opening duration was significantly prolonged in the infratentorial lesion group. We have demonstrated that quantitative temporal analysis of VFSS can be a clinically valuable tool identifying dysphagia pattern associated with stroke lesion or aspiration risk.

Reference Values for Videofluoroscopic Measures of Swallowing: An Update

PURPOSE

It is essential that clinicians have evidence-based benchmarks to support accurate diagnosis and clinical decision making. Recent studies report poor reliability for diagnostic judgments and identifying mechanisms of impairment from videofluoroscopy (VFSS). Establishing VFSS reference values for healthy swallowing would help resolve such discrepancies. Steele et al. (2019) released preliminary reference data for quantitative VFSS measures in healthy adults aged < 60 years. Here, we extend that work to provide reference percentiles for VFSS measures across a larger age span.

METHOD

Data for 16 VFSS parameters were collected from 78 healthy adults aged 21-82 years (39 male). Participants swallowed three comfortable sips each of thin, slightly, mildly, moderately, and extremely thick barium (20% w/v). VFSS recordings were analyzed in duplicate by trained raters, blind to participant and task, using the Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) Method. Reference percentiles (p2.5, 5, 25, 50, 75, 95, and 97.5) were determined as per Clinical and Laboratory Standards Institute EP28-A3c guidelines.

RESULTS

We present VFSS reference percentile tables, by consistency, for (a) timing parameters (swallow reaction time; the hyoid burst-to-upper esophageal sphincter (UES)-opening interval; UES opening duration; time-to-laryngeal vestibule closure (LVC); and LVC duration) and (b) anatomically scaled pixel-based measures of maximum UES diameter, pharyngeal area at maximum pharyngeal constriction and rest, residue (vallecular, pyriform, other pharyngeal locations, total), and hyoid kinematics (X, Y, XY coordinates of peak position; speed). Clinical decision limits are proposed to demarcate atypical values of potential clinical concern.

CONCLUSION

These updated reference percentiles and proposed clinical decision limits are intended to support interpretation and reliability for VFSS assessment data.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24043041.

Expanding Rehabilitation Options for Dysphagia: Skill-Based Swallowing Training

Over the past four decades, our understanding of swallowing neural control has expanded dramatically. However, until recently, advances in rehabilitation approaches for dysphagia have not kept pace, with a persistent focussing on strengthening peripheral muscle. This approach is no doubt very appropriate for some if not many of our patients. But what if the dysphagia is not due to muscles weakness? The purpose of this clinical manuscript is to reflect on where we have been, where we are now and perhaps where we need to go in terms of our understanding of swallowing motor control and rehabilitation of motor control impairments. This compilation is presented to clinicians in the hope that suggesting approaches "outside the box" will inspire clinicians to focus their attention "inside the box" to ultimately improve rehabilitation and long-term outcomes for patients with dysphagia.

Voluntary Cough Testing as a Clinical Indicator of Airway Protection in Cervical Spinal Cord Injury

OBJECTIVE

Voluntary cough testing (VCT) may be useful for determining aspiration risk in neurogenic dysphagia; however, has yet to be investigated in traumatic cervical spinal cord injury (tCSCI). The study explored if VCT may elucidate swallowing safety and kinematics related to airway protection in tCSCI survivors.

METHODS

Ten inpatients, 13-73 days post-tCSCI (7 incomplete injuries), completed VCT and a modified barium swallowing study that was analyzed via the Penetration Aspiration Scale (PAS) and norm-referenced measures of swallowing events related to airway protection. Spearman rho correlations explored relations among cough airflow, median PAS, and airway protection. Mann-Whitney U tests explored group differences based on clinical airway invasion (PAS > 2) and receiver operating characteristic statistics probed the sensitivity/specificity of VCT measures.

RESULTS

Safe (PAS > 2) and unsafe swallowers differed by cough volume acceleration (CVA) for the total sample and by inspiratory duration for incomplete injuries (p = 0.03, r > 0.7). A cut-off value of 24.8 L/s for CVA predicted airway invasion (AUC = 0.917, p = 0.03) with sensitivity = 100%/specificity = 75%. CVA correlated with delayed laryngeal vestibule closure during swallowing for both the total sample and for incomplete injuries (r_s  > 0.6, p < 0.05). Blunted peak flow and prolonged cough phases were associated with disordered laryngeal kinematics and prolonged bolus transit during swallowing (p < 0.05).

CONCLUSIONS

Reduced CVA, blunted peak flow, and prolonged cough phases reflected PAS and disrupted mechanisms of airway protection in tCSCI survivors, demonstrating promise for VCT as a clinical assessment for post-tCSCI dysphagia.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Submental transcutaneous electrical stimulation can impact the timing of laryngeal vestibule closure

Background

Laryngeal vestibule closure (LVC) is one of the critical airway protection mechanisms during swallowing. LVC timing impairments during swallowing are among the common causes of airway invasion in patients with dysphagia.

Objectives

To understand whether using submental transcutaneous electrical stimulation (TES) with varying pulse durations can impact the LVC reaction time (LVCrt) and LVC duration (LVCd) measures in healthy adults.

Methods

Twenty‐six healthy adults underwent three TES conditions while receiving three trials of 10 ml pureed: no TES, TES with short pulse duration (300 μs) and TES with long pulse durations(700 μs). Two pairs of electrodes were placed diagonally on the submental area. For each active TES condition, the stimulation was increased up to the participant's self‐identified maximum tolerance. Each swallow trial was recorded using videofluoroscopic swallowing study. All data were extracted and analysed offline using VideoPad Video Editor program.

Results

Submental TES reduced LVCrt during swallowing [F (2, 46) = 7.234, p < .007, ηp2 = .239] but had no significant impact on LVCd [F (2, 50) = .1.118, p < .335, ηp2 = .043]. Furthermore, pulse duration had no distinguished impact on any LVC timing measures.

Conclusion

Transcutaneous electrical stimulation may benefit patients with dysphagia who suffer from delayed LVC during swallowing. Future studies should seek whether the same physiologic effect can be observed in patients with dysphagia.

Can Videofluoroscopic Swallowing Kinematic Analysis Predict Recovery of Oral Intake in Postoperative Oral Cancer Patients Requiring Nasogastric Tube Feeding?

This retrospective study determined the significant predictive factors for the number of days required to remove nasogastric tubes (NGTs) after surgery in patients with oral cancer (OC). In this study, patients underwent a videofluoroscopic swallowing study (VFSS) approximately 2 weeks after surgery. Videofluoroscopic images were analyzed, and variables such as swallowing and swallowing kinematics were measured. Patient characteristics, swallowing kinematics, and swallowing results were assessed using a Cox proportional hazards model. This study assessed 129 participants (66 men, 63 women, mean age: 69.0 ± 14.1 years) with nine types of cancer. The Cox proportional hazard ratio revealed that sex, body mass index before surgery, radiotherapy and/or chemotherapy, dysphagia before surgery, normalized pharyngeal constriction ratio, upper esophageal sphincter (UES) opening, and laryngeal vestibule disclosure (LVC) disorder were predictive factors for the removal of NGTs when adjusted for age. The study identified several predictive factors for the removal of NGTs and oral intake recovery in patients with OC. Regarding swallowing kinematics, UES opening is the most significant predictive factor. After surgery for OC, VFSS should be performed to assess safe eating methods and predict the recovery of oral intake and removal of the NGT.

A Retrospective Analysis of Swallowing Function and Physiology in Patients Living with Dementia

Dysphagia is commonly diagnosed in patients living with dementia, but we lack understanding of changes in swallowing physiology and the resulting relationship to impairments of safety and efficiency. The purpose of this study was to describe the pathophysiology of dysphagia in a retrospective sample of patients living with dementia. Videofluoroscopy data from 106 adults (mean age: 84) diagnosed with dementia were scored by blinded raters. Raters analyzed 412 thin liquid swallows for safety [Penetration-Aspiration Scale (PAS)], efficiency [% of (C2-C4)²], timing [Pharyngeal Transit Time (PTT), Swallow Reaction Time (SRT), Laryngeal Vestibule Closure Reaction Time (LVCrt), Upper Esophageal Sphincter Opening Duration (UESO)], and kinematics (pharyngeal constriction). Impairment thresholds from existing literature were used to characterize swallowing. Chi-square tests and Pearson's correlations were used to determine associations between swallowing physiology and function. Compared to published norms, we identified significant differences in PTT, SRT, LVCrt, UESO, and degree of maximum pharyngeal constriction. Unsafe swallowing (PAS > 2) was seen in 17% of swallows. Clinically significant residue (i.e., % of (C2-C4)² > 0.54 vallecular; > 0.34 pyriforms) was seen in most patients. Chi-square tests revealed significant associations between LVCrt and unsafe swallowing. There was a weak positive association between post-swallow residue in the pyriforms and poor pharyngeal constriction. Detailed analysis of swallowing physiology in this sample provides insight into the pathophysiological mechanisms associated with dysphagia in patients living with dementia. Further work is needed to explore additional bolus consistencies and to identify how physiology changes based on type and severity of dementia diagnosis.

Reflex vs. volitional cough differences amongst head and neck cancer survivors characterized by time since treatment and aspiration status

BACKGROUND

The aim of this study was to investigate differences in reflexive and volitional cough airflows in advanced stage head and neck cancer survivors as it relates to aspiration status and time since treatment. The hypothesis is that those who aspirate several years after treatment completion would demonstrate reduced airflows for all cough parameters compared to those recently status post treatment completion given the known progressive deterioration associated with radiotherapy.

METHODS

Demographic and airflow data during both reflexive and volitional cough tasks and aspiration status as determined during fiberoptic endoscopic evaluation of swallow function were collected from 33 Head and Neck Cancer (HNC) survivors.

RESULTS

Omnibus MANOVA for dependent airflow variables and independent variables aspiration status, time since treatment and cough type (reflex or volitional) was significant (F(3,1) = 184, p < 0.000) indicating that peak expiratory flow rates (PEFR) were reduced under reflex (mean PEFR 1.88 SD 0.7) versus volitional (mean PEFR 2.3, SD 0.7) cough types; reduced for aspirators versus non-aspirators (F(2,1) = 4.1, p = 0.04) and reduced for those in the subacute versus chronic phase status post Intensity Modulated Radiotherapy (IMRT) (F(2,1) = 10.05, p = 0.002).

CONCLUSION

Findings of reduced reflexive compared to volitional cough airflows in head and neck cancer survivors are consistent with those from both healthy and other diseased populations. Additional findings that aspirators demonstrate reduced cough airflows compared to non-aspirators supports the hypothesis. Surprisingly, those recently status post treatment completion show worse cough airflows compared to those remotely status post treatment completion.

Impact of the Chin-Down Posture on Temporal Measures of Patients With Dysphagia: A Pilot Study

Purpose The chin-down position is a commonly prescribed posture by health care professionals to alleviate the symptoms of dysphagia. Yet, how the technique influences swallowing physiology lacks clarity. Our goal was to examine the impact of the postural technique on patients with various medical conditions and swallowing impairments. Method Temporal and functional measures were examined with videofluoroscopy in the chin-down and neutral head position on 15 patients. Also, timing differences between head positions were examined to determine the presence of improvement during the chin-down posture. Results The primary finding was chin-down posture swallows prolonged the elapsed time between when the prematurely spilled bolus entered the pharynx relative to swallow onset compared to the neutral head position (p = .006). Also, no improvement in airway protection was found when performing the postural technique. Conclusions The chin-down posture may benefit patients with specific swallowing impairments. However, the general use of the technique for all patients who experience swallowing difficulty might be negligent and could potentially have adverse or no effect on patient outcomes. Future studies examining patients with the same pathophysiology are needed to understand the benefit of the chin-down posture based on swallowing impairment.

The Influence of Surface Electromyography Visual and Clinician Verbal Feedback on Swallow Effort Ratio at Different Bolus Volumes in a Healthy Population

BACKGROUND/AIMS

The effortful swallow is a common treatment intervention requiring increased intensity to facilitate adaptations and modify swallow kinematics. The type of feedback and bolus volume provided may influence the intensity of the effortful swallow. To determine the increased effortful swallow intensity, a clinician can collect the peak amplitude of an effortful swallow and a typical swallow and compute a "swallow effort ratio" (SER). Dividing the effortful swallow surface electromyography (sEMG) peak amplitude by the typical swallow sEMG peak amplitude derives the SER. A higher SER suggests increased intensity. An increase in the SER may have clinical relevance in swallowing therapy as a threshold of intensity is required to elicit neuroplastic change. The purpose of this investigation was to determine whether sEMG visual and clinician verbal feedback increases the SER. Additionally, the investigation examined whether the SER is influenced by different liquid bolus volumes.

METHODS

Eighty-two nondysphagic, healthy adults were assigned at random to 2 groups. One group received no feedback, and the other received verbal and visual feedback while performing typical and effortful swallows at 3 liquid volumes.

RESULTS

An analysis of covariance compared the typical and effortful peak swallow amplitudes among 3 volumes in the 2 feedback groups. There was a significant effect on the peak amplitude values by feedback group F(2, 79) = 22.82, p < 0.001. There were no differences in peak amplitude by volume regardless of feedback F(2, 78) = 0.413, p = 0.663.

CONCLUSION

It appears that sEMG visual and clinician verbal feedback increases the SER, which may be a surrogate for intensity. An increased SER may have a positive effect on swallow intervention as intensity is known to influence outcomes of exercise and elicit neuroplastic change.

Predictors of Residue and Airway Invasion in Parkinson's Disease

Dysphagia is a highly prevalent disorder in Parkinson's Disease (PD) characterized by changes in swallowing kinematics, residue, and airway invasion. These changes can lead to serious medical morbidities including malnutrition, aspiration pneumonia, and death. However, little is known about the most predictive causes of residue and airway invasion in this patient population. Therefore, the aims of this study were to (1) assess how disease severity affects residue, airway invasion, and swallowing kinematics in PD; and (2) determine which swallowing kinematic variables were most predictive of residue and airway invasion. A secondary analysis of forty videofluoroscopic swallow studies (VFSS) from individuals with early through mid-stage PD was performed. Airway invasion (Penetration-Aspiration Scale 'PAS'), residue (Bolus Clearance Ratio 'BCR'), and ten spatiotemporal swallowing kinematic variables were analyzed. Statistical analyses were used to determine if disease severity predicted residue, depth of airway invasion, and swallowing kinematics, and to examine which swallowing kinematic variables were most predictive of residue and the presence of airway invasion. Results revealed that residue and the presence of airway invasion were significantly predicted by swallowing kinematics. Specifically, airway invasion was primarily influenced by the extent and timing of airway closure, while residue was primarily influenced by pharyngeal constriction. However, disease severity did not significantly predict changes to swallowing kinematics, extent of residue, or depth of airway invasion during VFSS assessment. This study comprehensively examined the pathophysiology underlying dysphagia in people with early to mid-stage PD. The results of the present study indicate that disease severity alone does not predict swallowing changes in PD, and therefore may not be the best factor to identify risk for dysphagia in PD. However, the swallowing kinematics most predictive of residue and the presence of airway invasion were identified. These findings may help to guide the selection of more effective therapy approaches for improving swallowing safety and efficiency in people with early to mid-stage PD.

Effects of bolus consistency and reclining position on kinematic swallowing events in analysis using 320-row area detector computed tomography

This study used 320-row area detector computed tomography (320-ADCT) to determine whether kinematic swallowing events and bolus movement through the oropharynx are affected by bolus consistency and angle of recline. Fourteen healthy adults (4 men, 10 women; age, 22-90 years) underwent 320-ADCT assessment during three 10-mL barium swallow tests, with honey-thick liquid at 60° recline (60°thick), thin liquid at 60° recline (60°thin), and thin liquid at 45° recline (45°thin). The times of swallowing events were measured and compared among the different tests. Bolus propulsion, onset time of true vocal cord (TVC) closure, and upper esophageal sphincter opening were significantly earlier for 60°thin than for 60°thick. Onset time did not significantly differ between 60°thin and 45°thin; however, greater variability was noted for onset of TVC closure with 45°thin, as the TVC started to close before onset of swallowing in 30% of participants. Modulation of TVC closure depends on bolus transport in different reclining positions. The 45° reclining position elicited pre-swallow TVC closure in some participants, which suggests that excessive recline can increase perceived risk of airway invasion during swallowing.

Physiological Compensation for Advanced Bolus Location at Swallow Onset: A Retrospective Analysis in Healthy Seniors

Purpose Previous work has established that advanced bolus location at swallow onset (BLSO) alone is not correlated with an increased swallowing safety risk in healthy seniors. The primary goal of this retrospective study was to examine whether healthy seniors systematically alter their laryngeal vestibule closure reaction time (LVCrt) to maintain a safe swallow in the context of advanced BLSO. The secondary goal was to determine if longer LVCrt distinguished Penetration-Aspiration Scale (PAS; Rosenbek, Robbins, Roecker, Coyle, & Wood, 1996) scores of 1 versus 2. Method Videofluoroscopy studies from 43 healthy seniors (21 men, 22 women; M _age = 76.7 years, SD = 7.2) were analyzed. LVCrt was calculated for 3 × 5 ml and 3 × 20 ml thin liquid barium boluses per participant. PAS and BLSO (Modified Barium Swallow Impairment Profile Component 6) were scored for all swallows. Reliability (intraclass correlation coefficient > .75) was established on all measures. A linear mixed-effects regression was run to examine the effect of PAS and BLSO on LVCrt while controlling for bolus volume and repeated swallow trial. Results There was a main effect of BLSO (F = 4.6, p = .004) and PAS (F = 29.3, p < .001) on LVCrt. Post hoc pairwise comparisons revealed that LVCrt was significantly faster in BLSO scores of 3 (pyriforms) compared to scores of both 0 (posterior angle of the ramus) and 1 (valleculae). Significantly prolonged LVCrt was observed in PAS scores of 2 in comparison to 1. No significant main effects of bolus volume or trial, or interactions, were observed. Conclusions Our findings suggest that healthy seniors compensate for advanced BLSO by increasing their LVCrt. Furthermore, faster LVCrt was shown to distinguish PAS scores of 1 versus 2. Additional work should explore the relationship between LVCrt, BLSO, and PAS scores in dysphagic populations, specifically those with known sensory impairments.

Reference Values for Healthy Swallowing Across the Range From Thin to Extremely Thick Liquids

Purpose Thickened liquids are frequently used as an intervention for dysphagia, but gaps persist in our understanding of variations in swallowing behavior based on incremental thickening of liquids. The goal of this study was to establish reference values for measures of bolus flow and swallowing physiology in healthy adults across the continuum from thin to extremely thick liquids. Method A sex-balanced sample of 38 healthy adults underwent videofluoroscopy and swallowed 20% weight-to-volume concentration barium prepared in thin and slightly, mildly, moderately, and extremely thick consistencies using a xanthan gum thickener. Participants took comfortable sips and swallowed without a cue; sip volume was measured based on presip and postsip cup weights. A standard operating procedure (the ASPEKT method: Analysis of Swallowing Physiology: Events, Kinematics and Timing) was used to analyze videofluoroscopy recordings. Results The results clarify that, for thin liquid sips (10-14 ml), a single swallow without clearing swallows is typical and is characterized by complete laryngeal vestibule closure, complete pharyngeal constriction, and minimal postswallow residue. Aspiration was not seen, and penetration was extremely rare. Bolus position at swallow onset was variable, extending as low as the pyriform sinuses in 37% of cases. With thicker liquids, no changes in event sequencing, laryngeal vestibule closure, pharyngeal constriction, or postswallow residue were seen. The odds of penetration were significantly reduced. A longer timing interval until onset of the hyoid burst movement was seen, with an associated higher bolus position at swallow onset. Other timing measures remained unaffected by changes in bolus consistency. Conclusion The results include new reference data for swallowing in healthy adults across the range from thin to extremely thick liquids.

The association between temporal measures of swallowing with penetration and aspiration in patients with dysphagia: A meta-analysis

INTRODUCTION

Temporal features of swallowing physiology vary with age in healthy normals and have the potential to impact swallow safety and efficiency in patients with dysphagia. We conducted a meta-analysis to assess the relation between temporal features of swallowing with penetration, aspiration and residue in adult patients with dysphagia regardless of etiology.

METHODS

Operational definitions of relevant terms were defined a priori. A search of 5 databases was conducted to November 2016 without restriction to language. Two independent raters reviewed abstracts and full articles, with discrepancies resolved by consensus. All accepted articles advanced to data extraction and critical appraisal according to Cochrane standards. Analysis of pooled data compared measures between groups.

RESULTS

Of the 11 articles accepted, the temporal measures used in three or more studies were grouped into morphofunctional categories: bolus transit time; pharyngeal response time; laryngeal closure time; and upper esophageal opening time. Across all selected articles, definitions varied for abnormal swallow and only 4 articles reported rater blinding and reliability for measures related to timing. Pooled data identified two main findings: a. longer pharyngeal response time was associated with penetration and/or aspiration (MD = 0.40 95% CI 0.59 - 0.22), and longer upper esophageal opening duration was associated with only aspiration (PAS ≥ 6) (MD = 0.09 95% CI 0.16 - 0,02). No studies were found that related temporal measures and residue.

CONCLUSION

Our pooled findings identified an association of two temporal measures with penetration and/or aspiration but none with residue. The current evidence remains limited due to the heterogeneity across studies in how swallow measures were operationalized. Future work with a standardized and reproducible approach is direly needed.

A Survey of Clinician Decision Making When Identifying Swallowing Impairments and Determining Treatment

PURPOSE

Speech-language pathologists (SLPs) are the primary providers of dysphagia management; however, this role has been criticized with assertions that SLPs are inadequately trained in swallowing physiology (Campbell-Taylor, 2008). To date, diagnostic acuity and treatment planning for swallowing impairments by practicing SLPs have not been examined. We conducted a survey to examine how clinician demographics and swallowing complexity influence decision making for swallowing impairments in videofluoroscopic images. Our goal was to determine whether SLPs' judgments of swallowing timing impairments align with impairment thresholds available in the research literature and whether or not there is agreement among SLPs regarding therapeutic recommendations.

METHOD

The survey included 3 videofluoroscopic swallows ranging in complexity (easy, moderate, and complex). Three hundred three practicing SLPs in dysphagia management participated in the survey in a web-based format (Qualtrics, 2005) with frame-by-frame viewing capabilities. SLPs' judgments of impairment were compared against impairment thresholds for swallowing timing measures based on 95% confidence intervals from healthy swallows reported in the literature.

RESULTS

The primary impairment in swallowing physiology was identified 67% of the time for the easy swallow, 6% for the moderate swallow, and 6% for the complex swallow. On average, practicing clinicians mislabeled 8 or more swallowing events as impaired that were within the normal physiologic range compared with healthy normative data available in the literature. Agreement was higher among clinicians who report using frame-by-frame analysis 80% of the time. A range of 19-21 different treatments was recommended for each video, regardless of complexity.

CONCLUSIONS

Poor to modest agreement in swallowing impairment identification, frequent false positives, and wide variability in treatment planning recommendations suggest that additional research and training in healthy and disordered swallowing are needed to increase accurate dysphagia diagnosis and treatment among clinicians.

"Hidden in Plain Sight": A Descriptive Review of Laryngeal Vestibule Closure

A major emphasis in the evaluation of swallowing is to identify physiological abnormalities in swallowing that contribute to or explain unsafe swallowing (i.e., ingested material enters the trachea; post-swallow residue in the pharynx). Impairments in laryngeal vestibule closure are widely recognized as one of the major causes of unsafe swallowing, as it is the primary mechanism and first line of defense for preventing material from penetrating the airway during swallowing. However, this complex mechanism is often overlooked and understudied in swallowing research and dysphagia management. The purpose of this review is to promote a better understanding of the mechanism of laryngeal vestibule closure. We discuss where gaps in research exist and propose future directions for incorporating laryngeal vestibule closure as a primary outcome measure in swallowing research. Additionally, we propose that an increased knowledge of the mechanism of laryngeal vestibule closure will increase diagnostic accuracy and optimize dysphagia management for patients with dysphagia.

The effect of transcutaneous neuromuscular electrical stimulation on laryngeal vestibule closure timing in swallowing

Background

The purpose of this study was to investigate the effect of transcutaneous neuromuscular electrical stimulation (NMES) on the timing of laryngeal vestibule closure during the pharyngeal stage of swallowing in healthy adults. The theoretical framework proposed that NMES applied to these muscles would present a perturbation to laryngeal vestibular closure reaction time (the amount of time for the laryngeal vestibule to close once the swallowing reflex has been triggered) by providing an antagonistic force to the direction of vestibule closure.

Methods

Nine healthy adults (2 males, 7 females) received ten consecutive stimulations applied to the submandibular hyolaryngeal muscles while performing dry swallows. Laryngeal vestibule closure reaction time (LVCrt) and the laryngeal vestibule closure duration (LVCd) were measured from videoflouroscopic images pre-stimulation and post-stimulation.

Results

Results indicated a significant effect of stimulation on LVCrt but not LVCd. LVCrt was significantly reduced (timing was faster) during swallows immediately after stimulation compared to pre-stimulation.

Conclusions

Findings from this study support the supposition that laryngeal muscles respond to perturbations via adaptation learning, which might be used for rehabilitation of neuromuscular swallowing impairment. This pilot study supports the need for further research.

A Preliminary Videofluoroscopic Investigation of Swallowing Physiology and Function in Individuals with Oculopharyngeal Muscular Dystrophy (OPMD)

Dysphagia is one of the primary symptoms experienced by individuals with Oculopharyngeal Muscular Dystrophy (OPMD). However, we lack understanding of the discrete changes in swallowing physiology that are seen in OPMD, and the resulting relationship to impairments of swallowing safety and efficiency. This study sought to describe the pathophysiology of dysphagia in a small sample of patients with OPMD using a videofluoroscopy examination (VFSS) involving 3 × 5 mL boluses of thin liquid barium (22% w/v). The aim of this study is to extend what is known about the pathophysiology of dysphagia in OPMD, by quantifying changes in swallow timing, kinematics, safety, and efficiency, measured from VFSS. This study is a secondary analysis of baseline VFSS collected from 11 adults (4 male), aged 48-62 (mean 57) enrolled in an industry-sponsored phase 2 therapeutic drug trial. Blinded raters scored the VFSS recordings for safety [Penetration-Aspiration Scale (PAS)], efficiency [Normalized Residue Ratio Scale (NRRS)], timing [Pharyngeal Transit Time (PTT), Swallow Reaction Time (SRT), Laryngeal Vestibule Closure Reaction Time (LVCrt), Upper Esophageal Sphincter Opening Duration (UESD)], and kinematics (hyoid movement, pharyngeal constriction, UES opening width). Impairment thresholds from existing literature were defined to characterize swallowing physiology and function. Further, Fisher's Exact tests and Pearson's correlations were used to conduct a preliminary exploration of associations between swallowing physiology (e.g., kinematics, timing) and function (i.e., safety, efficiency). Compared to published norms, we identified significant differences in the degree of maximum pharyngeal constriction, hyoid movement distance and speed, as well as degree and timeliness of airway closure. Unsafe swallowing (PAS ≥ 3) was seen in only 3/11 patients. By contrast, clinically significant residue (i.e., NRRS scores ≥ 0.09 vallecular; ≥ 0.2 pyriform) was seen in 7/11 patients. Fisher's Exact tests revealed associations between prolonged SRT, PTT, and unsafe swallowing. Weak associations were also identified between post-swallow residue and poor pharyngeal constriction during the swallow. Detailed analysis of swallowing physiology in this series of adults with OPMD aligns with impaired muscular function (e.g., reduced pharyngeal constriction, incomplete laryngeal vestibule closure) associated with the disease, and primary functional challenges with swallow efficiency. Further work is needed to explore a greater range of food and liquid textures, and to identify additional physiological mechanisms underlying swallowing impairment in OPMD.