Fatigue Analysis Before and After Shaker Exercise: Physiologic Tool for Exercise Design

Recent studies suggest that the Shaker exercise induces fatigue in the upper esophageal sphincter (UES) opening muscles and sternocleidomastoid (SCM), with the SCMs fatiguing earliest. The aim of this study was to measure fatigue induced by the isometric portion of the Shaker exercise by measuring the rate of change in the median frequency (MF rate) of the power spectral density (PSD) function, which is interpreted as proportional to the rate of fatigue, from surface electromyography (EMG) of suprahyoid (SHM), infrahyoid (IHM), and SCM. EMG data compared fatigue-related changes from 20-, 40-, and 60-s isometric hold durations of the Shaker exercise. We found that fatigue-related changes were manifested during the 20-s hold. The findings confirm that the SCM fatigues initially and as fast as or faster than the SHM and IHM. In addition, upon completion of the exercise protocol, the SCM had a decreased MF rate, implying improved fatigue resistance, while the SHM and IHM showed increased MF rates, implying that these muscles increased their fatiguing effort. We conclude that the Shaker exercise initially leads to increased fatigue resistance of the SCM, after which the exercise loads the less fatigue-resistant SHM and IHM, potentiating the therapeutic effect of the Shaker exercise regimen with continued exercise performance.

Augmentation of Deglutitive Thyrohyoid Muscle Shortening by the Shaker Exercise

Earlier studies of the effect of 6 weeks of the Shaker Exercise have shown significant increase in UES opening and anterior excursion of larynx and hyoid during swallowing in patients with upper esophageal sphincter (UES) dysfunction, resulting in elimination of aspiration and resumption of oral intake. This effect is attributed to strengthening of the suprahyoid muscles, as evidenced by comparison of electromyographic changes in muscle fatigue before and after completion of the exercise regime. The effect of this exercise on thyrohyoid muscle shortening is unknown. Therefore the aim of this study was to determine the effect of the exercise on thyrohyoid muscle shortening. We studied 11 dysphagic patients with UES dysfunction. Six were randomized to traditional swallowing therapy and five to the Shaker Exercise. Videofluoroscopy was used to measure deglutitive thyrohyoid shortening before and after completion of assigned therapy regimen. Maximum thyrohyoid muscle shortening occurred at close temporal proximity to the time of maximal thyroid cartilage excursion. The percent change in thyrohyoid distance from initiation of deglutition to maximal anterior/superior hyoid excursion showed no statistically significant difference between the two groups prior to either therapy (p = 0.54). In contrast, after completion of therapy, the percent change in thyrohyoid distance in the Shaker Exercise group was significantly greater compared to the traditional therapy (p = 0.034). The Shaker Exercise augments the thyrohyoid muscle shortening in addition to strengthening the suprahyoid muscles. The combination of increased thyrohyoid shortening and suprahyoid strengthening contributes to the Shaker Exercise outcome of deglutitive UES opening augmentation.

Aspiration and the elderly

Aspiration is prevalent in the elderly but its association with impairment of oral intake and gastroesophageal reflux is often misunderstood. This paper describes the causes, pathophysiology, and consequences of aspiration and their unique features in aged persons. It also explains how videofluoroscopic evaluation can assess current function while limiting factors that result in misinformation. The management of aspiration is discussed, emphasizing the importance and difficulties in maintaining functional well-being and possible complications of therapy.     

Strength-Training Exercise in Dysphagia Rehabilitation: Principles,Procedures, and Directions for Future Research

Dysphagia rehabilitation, historically, has focused a great deal on various compensations during swallowing to prevent aspiration and/or improve safety and efficiency. Exercise, in general, has been a part of the dysphagia rehabilitation landscape. However, heightened discussions in the field regarding best practices for exercise training, particularly strengthening, raise more questions than answers. The intent of this paper is to (1) explore the overriding principles of neuromuscular plasticity with regard to strength training, (2) evaluate how current exercise-training interventions in dysphagia rehabilitation correspond to these principles, and (3) postulate directions for future study of normal and disordered swallowing and determine how to incorporate these principles into dysphagia rehabilitation.     

UES Opening and Cricopharyngeal Bar in Nondysphagic Elderly and Nonelderly Adults

The intent of the study was to investigate upper esophageal sphincter (UES) opening and cricopharyngeal bar, and their relationship to other swallowing variables, in elderly, nondysphagic subjects. Extent and duration of UES opening, hypopharyngeal transit time, hyoid displacement, hyoid-to-larynx approximation, and incomplete pharyngeal clearing were determined from fluoroscopic swallow studies in 84 nonelderly control subjects and 88 elderly subjects. No differences in these measures were found between elderly subjects with and without medical conditions, and data were subsequently pooled. Mild, moderate, or marked cricopharyngeal bars were identified in more than 30% of elderly subjects, and subsequent analyses were performed on the control group, the elderly group without bars, and the elderly group with bars. Maximum opening of the UES in the elderly bar group was significantly reduced compared with that of the elderly group without bars and the nonelderly control group. However, timing measures did not differentiate elderly subjects with bars from other elderly subjects and they suggest that prolonged transit times in the elderly cannot be explained by the presence of a cricopharyngeal bar. With the exception of hyoid displacement, all variables investigated differed significantly between the nonelderly and one or both of the elderly groups. With the exception of UES opening, variables examined generally did not differentiate the two elderly groups.     

Airway Protection: Evaluation with Videofluoroscopy

During videofluoroscopic swallowing studies performed in the lateral view, the arytenoid cartilages are seen to elevate and approximate the down-folding epiglottis, effectively closing the supraglottic larynx and protecting the airway. This mechanism may be incomplete or delayed in patients complaining of dysphagia and may lead to penetration of bolus material into the airway. This study evaluates the timing of supraglottic closure relative to the arrival of the bolus at the upper esophageal sphincter in 60 young control subjects and in 63 elderly control subjects without dysphagia. Event timing was measured in 0.01-s intervals from videofluoroscopic studies for two liquid bolus size categories. Results of the analysis revealed that, in most individuals, the arytenoid cartilages approximate the epiglottis prior to the arrival of the bolus at the upper esophageal sphincter. However, in both bolus size categories, there were individuals who achieved complete supraglottic closure after the bolus had arrived at the sphincter, but never greater than 0.1 s later. No delay in the timing of supraglottic closure relative to bolus arrival at the sphincter was found in the elderly subject group compared with the young subject group. The information from this study has allowed us to objectively determine if supraglottic closure timing is delayed in patients with dysphagia and to address any delay with strategies and exercises designed specifically to correct the delay. A case study is presented to illustrate the clinical significance of this study.     

Bolus Location at the Initiation of the Pharyngeal Stage of Swallowing in Healthy Older Adults

This study characterized the vertical position of the bolus head at the onset of the pharyngeal swallow in healthy older adults. Lateral-view videofluoroscopic (VF) images were obtained from ten healthy volunteers (age-71.6 ± 7.5 years, mean± SD) as they swallowed 5-cc thin liquid barium aliquots. For each swallow, the bolus head and several anatomic landmarks were digitally recorded from the image in which pharyngeal swallow-related hyoid bone elevation began. Vertical distance between the bolus head and the intersection of the tongue base and mandibular ramus (TMI) was computed. Bolus head position at swallow onset ranged from 47.4-mm above to 34.9-mm below the TMI (2.2 ± 14.4-mm, mean ± SD). Although the bolus head was below the level of the TMI for the majority of swallows, neither penetration nor aspiration occurred. For individual subjects, mean bolus head position ranged from 25.8 ± 5.0-mm above to 15.5 ± 6.5-mm below the TMI. Whereas five of ten subjects initiated the pharyngeal swallow with the bolus head consistently above or consistently below the TMI, five subjects initiated swallowing with the bolus head either above or below the TMI across trials. Older adults commonly initiate thin-liquid swallows with the bolus head well below the TMI without associated penetration or aspiration. Thus, bolus position alone does not differentiate between normal and pathologic swallowing within the healthy elderly. Bolus position at pharyngeal swallow onset can vary substantially from trial to trial within an individual, suggesting that the triggering of swallowing depends on multiple influences. This research was supported by NSERC grant No. 0GPO171208 and an Ontario Ministry of Health Career Scientist Award to REM.     

Development and dissemination of an aspiration risk reduction diet

Patients with oropharyngeal swallowing disorders secondary to neurologic impairments benefit from diets that minimize the risk of aspiration. An aspiration risk reduction diet was developed from our hospital's regular menu cycle. Examples of the diet's preparation, dissemination, and use in a 600-bed acute medical/surgical teaching hospital are discussed.     

Swallowing therapy of neurologic patients: Correlation of outcome with pretreatment variables and therapeutic methods

The results of swallowing therapy in 58 patients with neurologic disorders are presented. All patients received tube feeding, either partially or exclusively, at admission, and successful outcomes, defined as exclusively oral feeding, were achieved in 67% of patients over a median treatment interval of 15 weeks. A subset of 11 patients who had experienced disease onset 25 weeks or more prior to admission nonetheless had a similar success rate of 64%. No other pretreatment variable, including age, localization of lesion, type or degree of aspiration, or cognitive status, correlated with successful outcome. Indirect therapy methods such as stimulation techniques and exercises to enhance the swallowing reflex, alter muscle tone, and improve voluntary function of the orofacial, lingual, and laryngeal musculature were utilized in all but 1 patient. Direct methods including compensatory strategies such as head and neck positioning, and techniques such as supraglottic swallowing and the Mendelsohn maneuver were additionally employed in nearly one-half of patients. Swallowing therapy is associated with successful outcome, as defined by exclusively oral feeding, among patients with neurogenic dysphagia, regardless of pretreatment variables including time since disease onset. Indirect treatment methods appear to be effective when used either alone or in combination with direct methods. Achievement of oral feeding is not associated with undue risk of pneumonia. Further rigorous scientific studies are needed.     

Effects of Cuff Deflation and One-Way Tracheostomy Speaking Valve Placement on Swallow Physiology

This study examined the effects of tracheostomy cuff deflation and one-way speaking valve placement on swallow physiology. Fourteen nonventilator-dependent patients completed videofluoroscopic swallow studies (VFSS) under three conditions: (1) cuff inflated, (2) cuff deflated, and (3) one-way valve in place. Four additional patients with cuffless tracheostomy tubes completed VFSS with and without the one-way valve in place. All swallows were analyzed for the severity of penetration/aspiration using an 8-point penetration–aspiration scale. Seven preselected swallow duration measures, extent of hyolaryngeal elevation and anterior excursion, and oropharyngeal residue were also determined. Scores on the penetration–aspiration scale were not significantly affected by cuff status, i.e., inflation or deflation. However, one-way valve placement significantly reduced scores on the penetration–aspiration scale for the liquid bolus. Patients who are unable to tolerate thin liquids may be able to safely take thin liquids when the valve is in place. However, one-way valve placement may not be beneficial for all patients. Clinicians who complete VFSS with tracheostomized patients should include several bolus presentations with a one-way speaking valve in place before making any decisions regarding the use of the valve as a means to reduce aspiration. Work was performed at The University of Tennessee Medical Center, Knoxville, Tennessee.     

Simultaneous Modified Barium Swallow and Blue Dye Tests: A Determination of the Accuracy of Blue Dye Test Aspiration Findings

Abstract The overall objective of this pilot study was to determine blue dye test reliability and validity for the identification of aspiration of secretions, food, and/or drink in 50 simultaneously administered blue dye (BDT) and modified barium swallow (MBS) tests of tracheostomized individuals. With the MBS as an objective test of aspiration, BDT sensitivity and specificity identifying aspiration were less than 80% and 62%, respectively. Certain tracheostomy tube conditions and food consistencies were associated with more accurate BDT aspiration results than others. Characteristics of the aspiration episodes, interpretation of the results, and needs for further research are discussed.     

Clinical Utility of the 3-ounce Water Swallow Test

The 3-ounce water swallow test is frequently used to screen individuals for aspiration risk. Prior research concerning its clinical usefulness, however, is confounded by inadequate statistical power due to small sample sizes and varying methodologies. Importantly, research has been limited to a few select patient populations, thereby limiting the widespread generalizability and applicability of the 3-ounce test. The purpose of this study was to investigate the clinical utility of the 3-ounce water swallow test for determining aspiration status and oral feeding recommendations in a large and heterogeneous patient population. Fiberoptic endoscopic evaluation of swallowing (FEES) was performed in conjunction with the 3-ounce water swallow test on 3000 participants with a wide range of ages and diagnoses. A total of 1151 (38.4%) passed and 1849 (61.6%) failed the 3-ounce water swallow test. Sensitivity of the 3-ounce water swallow test for predicting aspiration status during FEES = 96.5%, specificity = 48.7%, and false positive rate = 51.3%. Sensitivity for identifying individuals who were deemed safe for oral intake based on FEES results = 96.4%, specificity = 46.4%, and false positive rate = 53.6%. Passing the 3-ounce water swallow test appears to be a good predictor of ability to tolerate thin liquids. However, failure often does not indicate inability to tolerate thin liquids, i.e., low specificity and high false-positive rate. Use of the 3-ounce water swallow test alone to make decisions regarding safety of liquid intake results in over-referral and unnecessary restriction of liquid intake for nearly 50% of patients tested. In addition, because 71% of participants who failed the 3-ounce water swallow test were deemed safe for an oral diet, nonsuccess on the 3-ounce water swallow test is not indicative of swallowing failure. The clinical utility of the 3-ounce water swallow test has been extended to include a wide range of medical and surgical diagnostic categories. Importantly, for the first time it has been shown that if the 3-ounce water swallow test is passed, diet recommendations can be made without further objective dysphagia testing.     

Answering Orientation Questions and Following Single-Step Verbal Commands: Effect on Aspiration Status

In the acute-care setting patients with altered mental status as a result of such diverse etiologies as stroke, traumatic brain injury, degenerative neurologic impairments, dementia, or alcohol/drug abuse are routinely referred for dysphagia testing. A protocol for dysphagia testing was developed that began with verbal stimuli to determine patient orientation status and ability to follow single-step verbal commands. Although unknown, it would be beneficial to ascertain if this information on mental status was predictive of aspiration risk. The purpose of this investigation was to determine if there was a difference in odds for aspiration based upon correctly answering specific orientation questions, i.e., 1. What is your name? 2. Where are you right now? and 3. What year is it?, and following specific single-step verbal commands, i.e., 1. Open your mouth. 2. Stick out your tongue. and 3. Smile. In a consecutive retrospective manner data from 4070 referred patients accrued between 1 December 1999 and 1 January 2007 were analyzed. The odds of liquid aspiration were 31% greater for patients not oriented to person, place, and time (odds ratio [OR] = 1.305, 95% CI = 1.134–1.501). The odds of liquid aspiration (OR = 1.566, 95% CI = 1.307–1.876), puree aspiration (OR = 1.484, 95% CI = 1.202–1.831), and being deemed unsafe for any oral intake (OR = 1.688, 95% CI = 1.387–2.054) were, respectively, 57, 48, and 69% greater for patients unable to follow single-step verbal commands. Being able to answer orientation questions and follow single-step verbal commands provides information on odds of aspiration for liquid and puree food consistencies as well as overall eating status prior to dysphagia testing. Knowledge of potential increased odds of aspiration allows for individualization of dysphagia testing thereby optimizing swallowing success.     

Manofluorographic analysis of swallowing in the elderly

This study examined the effect of aging on the mechanisms of swallowing by comparing 16 elderly subjects (80 years±5) with 20 healthy volunteers. Manofluorography was used to obtain quantitative and qualitative data of the pharyngeal swallow. Aging is associated with a significant decrease in the level of negative pressure resulting from the opening of the upper esophageal sphincter and with a substantial number of incomplete relaxations of the sphincter. In addition, several qualitative changes were noted.     

Interjudge and intrajudge reliabilities in fiberoptic endoscopic evaluation of swallowing (fees) using the penetration-aspiration scale: a replication study

This study used Fiberoptic Endoscopic Evaluation of Swallowing (FEES(R)) to assess the reliability of the Penetration-Aspiration Scale (PAS) using 79 swallows and four judges in a replication of a study using videofluoroscopy (VFSS). The swallows were diagnosed using FEES, which allowed for comparison between the two techniques. The findings indicated that all categories of the PAS achieved adequate reliability, both on intrajudge and interjudge assessments. Reliabilities, with the exception of Scale Score 7, were higher in this study than in the original study by Rosenbek and associates. Data analysis indicated that judges were more highly consistent on second ratings compared with their original ratings, indicating a learning curve on the PAS. In addition, findings suggested that the FEES was more reliable on assessing penetration than VFSS, but that VFSS was more reliable on the assessment of the various severities of aspiration. The two techniques were equally effective in discriminating between penetration and aspiration. This study found that FEES was just as reliable as VFSS when using the PAS.     

Cine Magnetic Resonance Imaging with Single-Shot Fast Spin Echo for Evaluation of Dysphagia and Aspiration

The aim of this study was to determine the feasibility of and interest in evaluation of swallowing using dynamic magnetic resonance imaging (cine-MRI) in patients with dysphagia and aspiration caused by an abnormal pharyngeal phase of swallow. A cohort of six patients previously treated for head and neck cancer with persistent dysphagia and/or aspiration were evaluated an average of 47 months after treatment. The morphology and mobility of the oral, oropharyngeal, and laryngeal structures were analyzed using cine-MRI using single-shot fast spin echo technology. The qualitative observations were compared with a clinical fiberoptic swallowing evaluation. Swallowing physiology was analyzable for dry (saliva) swallow in all patients. MRI was well-tolerated by all six patients and no clinical aspiration occurred during the MRI. In five of six cases, further information on the cause of dysphagia was obtained using cine-MRI compared with the clinical evaluation alone. In the remaining case, cine-MRI confirmed the clinical evaluation. Cine-MRI using the dry swallow technique is feasible and without risk in patients with clinical aspiration. Cine-MRI is complementary to clinical evaluation of swallowing in patients with an abnormal pharyngeal phase of swallowing resulting from treatment of cancer.     

The probability of correctly predicting subglottic penetration from clinical observations

It is difficult to predict from clinical signs and symptoms which patients suffer from subglottic penetration of foods. Most investigators attempting to predict aspiration have used small numbers of patients and relatively unsophisticated statistical techniques. In this study, we utilized 249 patients to examine the predictive value of several clinical factors thought to be suggestive of subglottic penetration with discriminant analysis. Using this approach we were able to correctly predict about 2/3 of both those who aspirate and those who do not aspirate. This is better than others have reported but still inadequate for clinical purposes.     

Swallowing therapy with neurologic patients: Results of direct and indirect therapy methods in 66 patients suffering from neurological disorders

The results of direct and indirect therapy methods applied to 66 patients suffering from neurological disorders are presented. Variables considered were age, time since lesion, localization of central nervous system lesion, type of swallowing disorder (defined according to swallowing phase, type of aspiration and degree of aspiration), cognitive deficits (memory, planning/problem-solving, and attention deficits), and duration of therapy. Success of therapy was defined by progress in type, ease, and safety of feeding and by range of diet. Therapeutic outcome was correlated with the above-listed variables. The findings suggest that swallowing therapy is effective for patients with neurological disorders.     

Surface EMG measurements at the throat during dry and wet swallowing

Within the sphere of dysphagia management, there is a growing need for the development of noninvasive methods of quantification of swallowing disorders. The purpose of the present investigation was to determine if surface electromyogram (EMG) at the throat could be measured during swallowing. Surface EMG was measured from 35 normal human subjects during dry and wet swallowing. The EMG signals recorded were highpass filtered using digital fourth order highpass Butterworth filter to eliminate baseline variations. Spectral analysis was performed on the filtered signals. The mean power values of the surface EMG signals were then calculated. Paired t-test between the mean power values of surface EMG during dry and wet swallowing showed a statistically significant difference (p<0.005). The results of the study confirmed the hypothesis that surface EMG at the throat during swallowing could be measured. Mean power of surface EMG measurement provides a reliable noninvasive measure of swallowing.     

Use of the electroglottograph for measurement of temporal aspects of the swallow: Preliminary observations

The electroglottograph (EGG) is a noninvasive, electrical impedance device that was developed for observing vocal fold contact during phonation. After a thorough study of the frequency response characteristics of the EGG, we found that the EGG output can be used to identify maximum laryngeal displacement and the duration of laryngeal movement during swallowing. With a small intranasal pressure transducer placed beneath the velum and the EGG electrodes placed externally on the thyroid cartilage, additional information on the temporal aspects of the swallow can be measured. The EGG has direct clinical application when teaching such techniques as the safe swallow and Mendelsohn maneuver and it is useful as a research technique when using repeated measures designed to study the swallow reflex.