The exeter dysphagia assessment technique

The Exeter Dysphagia Assessment Technique (EDAT) uses noninvasive equipment to record, simultaneously, “feeding respiratory patterns,” the time drink entered the mouth, and associated swallow sounds during feeding. The easily portable equipment enabled patients' swallowing ability to be tested, at the bedside if necessary, using a small amount of fruit-flavored drink. The results appear in chart form. EDAT findings from groups of normal subjects aged 2–90 years were compared with those from patients with dysphagia of neurologic origin and normal subjects under experimental feeding conditions. The results revealed maturation of the feeding respiratory pattern in the teenage years and remarkable consistency thereafter. Differences in the recordings between the normal and abnormal subjects were sufficiently marked to allow the findings to be used in the diagnosis of other patients with dysphagia of doubtful neurologic cause. Interpretation of the charts and recorded timings of the oral and pharyngeal stages of swallowing permitted a more accurate identification of sensory nerve, motor nerve, and functional involvement causing dysphagia of neurologic origin and may be used as a guide to the origin of the sensory deficit.     

Cervical Auscultation Synchronized with Images from Endoscopy Swallow Evaluations

Cervical auscultation is the use of a listening device, typically a stethoscope in clinical practice, to assess swallow sounds and by some definitions airway sounds. Judgments are then made on the normality or degree of impairment of the sounds. Listeners interpret the sounds and suggest what might be happening with the swallow or causing impairment. A major criticism of cervical auscultation is that there is no evidence on what causes the sounds or whether the sounds correspond to physiologically important, health-threatening events. We sought to determine in healthy volunteers (1) if a definitive set of swallow sounds could be identified, (2) the order in which swallow sounds and physiologic events occur, and (3) if swallow sounds could be matched to the observed physiologic events. Swallow sounds were computer recorded via a Littmann stethoscope from 19 healthy volunteers (8 males, 11 females, age range = 18–73 years) during simultaneous fiberoptic laryngoscopy and respiration monitoring. Six sound components could be distinguished but none of these occurred in all swallows. There was a wide spread and a large degree of overlap of the timings of swallow sounds and physiologic events. No individual sound component was consistently associated with a physiologic event, which is a clinically significant finding. Comparisons of groups of sounds and events suggest associations between the preclick and the onset of apnea; the preclick and the start of epiglottic excursion; the click and the epiglottis returning to rest; the click and the end of the swallow apnea. There is no evidence of a causal link. The absence of a swallow sound in itself is not a definite sign of pathologic swallowing, but a repeated abnormal pattern may indicate impairment. At present there is no robust evidence that cervical auscultation of swallow sounds should be adopted in routine clinical practice. There are no data to support the inclusion of the technique into clinical guidelines or management protocols. More evaluation using imaging methods such as videofluoroscopy is required before this subjective technique is validated for clinical use by those assessing swallowing outside of a research context. Study performed at the Freeman Hospital, Newcastle upon Tyne, UK. This project was supported by the Stroke Association (grant 11/98). Presented in part at the ASHA Convention, Chicago, Illinois, 13–15 November 2003     

Interrater Reliability of Videofluoroscopic Swallow Evaluation

Abstract The past two decades have brought an enormous widening of interest in and knowledge about swallowing disorders. The most frequently used technique for swallow evaluation is X-ray videofluoroscopy. Most interventions are based on this examination. Only a few studies assessing interobserver reliability of videofluoroscopy have been published. The aim of our study was to assess the interobserver reliability of videofluoroscopy for swallow evaluation. Fifty-one consecutive dysphagic patients referred for videofluoroscopy were entered into the study regardless of their underlying disorder. The first swallow (5 ml of a semisolid radio-opague contrast media) of each patient was assessed in the lateral projection by 9 independent, experienced observers from different international swallow centers. All studies were evaluated according to a standardized protocol sheet and the interobserver reliability was calculated. The interobserver reliabilities assessed as kappa coefficient for parameters of the oral and pharyngeal phase, for the temporal occurrence of penetration/aspiration, and for the location of bolus residue ranged from 0.01 to 0.56. High reliability with an intraclass coefficient of 0.80 was achieved only with the well defined penetration/aspiration score. Our study underlines the need for exact definitions of the parameters assessed by videofluoroscopy, in order to raise interobserver reliability. To date, only aspiration is evaluated with high reliability by videofluoroscopy, whereas the reliability of all other parameters of oropharyngeal swallow is poor.     

Comparative Review of Techniques for Recording Respiratory Events at Rest and during Deglutition

The coordination between swallowing and respiration is essential for safe feeding, and noninvasive feeding-respiratory instrumentation has been used in feeding and dysphagia assessment. Sometimes there are differences of interpretation of the data produced by the various respiratory monitoring techniques, some of which may be inappropriate for observing the rapid respiratory events associated with deglutition. Following a review of each of the main techniques employed for recording resting, pre-feeding, feeding, and post-feeding respiration on different subject groups (infants, children, and adults), a critical comparison of the methods is illustrated by simultaneous recordings from various respiratory transducers. As a result, a minimal combination of instruments is recommended which can provide the necessary respiratory information for routine feeding assessments in a clinical environment.     

Impact of the diagnostic procedure on outcome measures of swallowing rehabilitation in head and neck cancer patients

This study was designed to determine whether swallow rehabilitation outcomes were affected by the type of evaluation procedure utilized by the clinician. The two evaluation techniques compared were the bedside examination and videofluoroscopy (the modified barium swallow). Ten institutions participated in this study, enrolling a total of 103 partial laryngectomized patients, 21 in the bedside arm and 82 in the videofluoroscopy arm. Data on recovery of oral intake were collected weekly. All patients received an X-ray study of swallow at 3 months after the operation. Mean time to oral intake of food was significantly lower in patients assessed with bedside examination. Overall swallow measures of transit times and swallow efficiencies after 3 months revealed significantly better function in the videofluoroscopy group. Results are discussed in terms of the visibility of swallow physiology with the two assessment techniques, the accuracy of therapy planning with the bedside examination versus videofluoroscopy and the ability of head and neck cancer patients to tolerate some aspiration without developing aspiration pneumonia. This research was funded by NIH grant PO1 CA40007     

Interrater and Intrarrater Reliability of the Exeter Dysphagia Assessment Technique Applied to Healthy Elderly Adults

The purpose of this study was to evaluate the inter- and intrarater reliabilities of the Exeter Dysphagia Assessment Technique in a sample of elderly adults. This procedure uses noninvasive methods to record aspects of oral motor efficiency and synchronization of respiration during swallowing with the aid of specially developed equipment. Changes in the direction of nasal air flow, time of lip or tongue/spoon contact, and the time/frequency of swallow sounds are monitored and analyzed. Seventy records were evaluated independently by three trained assessors on three consecutive occasions. Interrater reliability was found to be good to very good for five of the respiratory variables assessed and moderate for the sixth. Interrater agreement was also very good for three of the timed oropharyngeal events assessed and moderate for the fourth. Intrarater reliability was very good for the same five respiratory variables and moderate for the sixth. Intrarater agreement was also very good for three of the timed oropharyngeal events and moderate for the fourth. Repeat evaluations of these records showed that agreement between and within raters concerning the sixth respiratory variable was improved substantially when the charts were examined in an enlarged form that provided improved resolution. We conclude that the majority of variables monitored by the Exeter Dysphagia Assessment Technique can be evaluated very reliably.     

Radiation Dose in Videofluoroscopic Swallow Studies

Videofluoroscopy has become an increasingly important armament in the investigation and assessment of swallowing disorders. However, very little work has been published on the radiation dose used in such examinations and currently there is no national diagnostic reference level in the United Kingdom. Videofluoroscopy in our hospital is performed predominantly by one radiologist (IZM) in a single fluoroscopy room. We recorded the screening times of 230 patients over a 45-month period. Screening time ranged from 18 to 564 s (median = 171 s) associated with a median dose-area product of 1.4 Gy cm². This is below the third quartile level of 2.7 Gy cm² for all such examinations performed across the northern England. The effective dose associated with a typical videofluoroscopy dose-area product is 0.2 mSv. Videofluoroscopy is the most appropriate instrumental examination for assessing oropharyngeal swallow biomechanics and intervention strategies. This data set is based on the largest number of videofluoroscopy swallow studies published to date. Our results show that videofluoroscopy can be performed using minimal radiation doses. This study was performed at Freeman Hospital, Newcastle upon Tyne, UK.     

Dysphagia in cerebral palsy: A comparative study of the exeter dysphagia assesment technique and a multidisciplinary assessment

Eighteen children with cerebral palsy in a special school, most of whom had feeding difficulties, were studied to compare the diagnostic value of the Exeter Dysphagia Assessment Technique (EDAT) with an exhaustive clinical assessment undertaken by a multidisciplinary team experienced in the diagnosis and treatment of dysphagia of neurological origin. Four feeding skills were assessed by each method independently, viz. anticipation, intraoral sensory perception, oral-motor efficiency, and pharyngeal triggering. Comparison of the two sets of results showed agreement in at least 78% of the assessed skills. The possible reasons for the few discrepancies are discussed. The noninvasive EDAT equipment was easy to use with the children, who had a range of type and severity of cerebral palsy. The test was undertaken in their familiar surroundings and took 15 to 20 min per child. Interpretation of the results showed that EDAT provided a rapid, reliable diagnostic aid which assisted in the assessment of the degree of feeding impairment within each of the four feeding skills tested. The authors are very grateful for the financial support for this project which was provided partially by Action Research and partially by the Northcott Devon Medical Foundation     

Videofluoroscopic assessment of dysphagia in children with severe spastic cerebral palsy

Very little has been published about the characteristics and sequelae of dysphagia in children with neurological impairment. The swallowing difficulties encountered by children with spastic cerebral palsy are particularly debilitating and potentially lethal. However, aggressive evaluation and management of their feeding is typically deferred until they are medically or nutritionally compromised. Reports of the use of videofluoroscopy to analyze the swallowing patterns and presence or absence of aspiration in such children are rare. This paper describes the histories and analyzes the videofluorographic swallow studies of 22 patients with the primary diagnosis of severe spastic cerebral palsy. The ages of the subjects ranged from 7 months to 19 years. All had severe dysphagia and were slow, inefficient eaters. Fifteen patients (68.2%) demonstrated significant silent aspiration during their swallow study. Analysis of specific features of their swallowing patterns indicated that decreased or poorly coordinated pharyngeal motility was predictive of silent aspiration. Moderately to severely impaired oral-motor coordination was indicative of severity of feeding complications. Our data suggeest that early diagnostic workup, including baseline and comparative videofluoroscopic swallow studies, could be helpful in managing the feeding difficulties in these children and preventing chronic aspiration, malnutrition, and unpleasant lengthy mealtimes.     

Morphologic Parameters of Normal Swallowing Events Using Single-Shot Fast Spin Echo Dynamic MRI

This study was designed to determine visible and measurable morphological parameters in normal swallowing using dynamic MRI with single-shot fast spin echo (SSFSE), as a preliminary study in view of noninvasive MRI swallowing evaluation in patients with dysphagia. Seven healthy volunteers aged 24–40 underwent dynamic MRI with SSFSE, with a 1.5-T unit, using a head and neck antenna. Patients repeated dry swallow, water swallow, marshmallow swallow, cake swallow, and cookie chewing for a total of five series, with 15 acquisitions per series at a rate of 700 ms per acquisition. A checklist of swallowing events and anatomic landmarks was used to determine which anatomic landmarks are always visible, which phases or swallowing movements are always visible, and which landmarks can be used to measure oral and pharyngeal motion in swallowing. The oral preparatory, oral, and oropharyngeal phases of deglutition were visible in all cases. No aspiration, reflux, or abnormal residue was observed. Spatial resolution allowed for anatomical measurements of laryngeal elevation, oropharyngeal diameter, and tongue base and velum displacement in all cases. SSFSE dynamic MRI is pertinent for evaluation of the anatomical and physiological characteristics of swallow. The temporal parameters, however, cannot be studied using this technique. Motion artifacts preclude its use in the study of mastication. It remains complementary to videofluoroscopy and other techniques in swallow evaluation.     

Acoustic technique for determining timing of velopharyngeal closure in swallowing

A pure tone sound source was introduced at a nostril and monitored by a miniature accelerometer on the throat. During velopharyngeal closure in a swallow, the pure tone component in the accelerometer signal was attenuated. Throat accelerometer recordings were made simultaneously with videofluoroscopy of a modified barium swallow in adults with normal velopharyngeal mechanisms. It was verified that the period of sound attenuation corresponded to the period of velar closure. This noninvasive method of monitoring otherwise silent velopharyngeal closure holds promise for normative studies on swallowing function, as an adjunct method in longitudinal assessment, and as a training aid.     

Swallowing/ventilation interactions during oral swallow in normal children and children with cerebral palsy

Many children with cerebral palsy (CP) suffer from feeding disorders. Twenty children with spastic CP and 20 neurologically normal children (age range 6.2–12.9 years) were monitored with ultrasound imaging of the oral cavity synchronized with surface electromyographic (EMG) recordings of masseter and infrahyoid museles and respiratory inductance plethysmograph (RIP) recordings during feeding tasks. A lip-cup contact detector signaled contact of the drinking cup on the lip during liquid tasks. Children with CP required more time than normals for collection and organization of 5 ml and 75 ml liquid boluses for swallowing. The ventilatory preparation phase, recovery to baseline resting ventilatory pattern after swallowing, and total time for task completion were longer in children with CP for 5-ml and 75-ml tasks. The interval from lip-cup contact until alteration of ventilation from baseline resting ventilatory pattern was longer for children with CP during 75-ml tasks but not for 5-ml tasks. The interval from completion of the task-related cookie swallow until initiation of the next swallow was longer in children with CP than in normal children. These data provide evidence than children with CP manage solid boluses more easily than liquid boluses and small liquid boluses more easily than large liquid boluses. This investigation statistically confirms empirically based recommendations that children with CP be allowed more time to complete feeding tasks and consume small volume drinks rather than large volume drinks.     

Methodology for detecting swallowing sounds

The use of cervical auscultation in the evaluation of the pharyngeal swallow may become a part of the clinical evaluation of dysphagic patients. Though its use is based on subjective evaluation, an acoustic analysis of swallowing sounds might establish more objective criteria in the detection of swallowing disorders. The present study sought to investigate three aspects of the methodology for detecting swallowing sounds: (1) the type of acoustic detector unit suited to an acoustic analysis of the pharyngeal swallow, (2) the type of adhesive suited for the attachement of the detector, and (3) the optimal site for sound detection of the pharyngeal swallow. An accelerometer with double-sided paper tape was selected as the appropriate detector unit because of its wide range of frequency response and small attenuation level. Using this detector unit, swallowing sounds and noise associated with simulated laryngeal elevation and the carotid pulse were acquired at 24 sites on the neck in 14 normal subjects; these signals were acoustically analyzed. The determination of the optimal site for detecting swallowing sounds was based on the signal-to-noise ratio. The site over the lateral border of the trachea immediately inferior to the cricoid cartilage is the optimal site for detection of swallowing sounds because this site showed the greatest signal-to-noise ratio with the smallest variance. The site over the center of the cricoid cartilage and the midpoint between the site over the center of the cricoid cartilage and the site immediately superior to the jugular notch were also considered to be the most appropriate sites.     

A Pilot Study of Respiration and Swallowing Integration in Parkinson’s Disease: “On” and “Off” Levodopa

Parkinson's disease is associated with both swallowing and respiratory dysfunction, increasing the risk of aspiration and pneumonia. Previous studies have shown improvements in measurements of swallowing and respiration with levodopa; however, the studies are small and some studies show conflicting reports. The aim of this study was to further investigate the effect of levodopa on respiration. Ten patients with Parkinson's disease were tested "On" and "Off" levodopa. Assessments included Unified Parkinson's Disease Rating Scale (UPDRS), coordination of swallowing and respiration, timed-test of swallowing, lung function testing, and, qualitative assessment of swallowing. There was a nonsignificant trend to lower volume per swallow when "On" levodopa, significant reduction in lung function when "On" levodopa, but no difference in coordination of swallowing and respiration or qualitative assessment of swallowing. There was a significant increase in motor examination score of the UPDRS when "Off" levodopa compared to "On." There may be a reduction in efficiency of swallowing with levodopa medication without any apparent increase in risk of aspiration. These pilot data suggest that further evaluation with larger numbers of participants is justified.     

Volume accommodation during swallowing

Bolus volume is an important modifier of the biomechanical events of the oropharyngeal swallow. The biomechanical events comprising a swallow can be divided into events associated with the reconfiguration of the pharynx into a swallow pathway and events associated with bolus transport from the oropharynx into the esophagus. Volume modification is achieved differently for the events of reconfiguration and propulsion. In the case of reconfiguration, a longer time is allocated to the process, as exemplified by sustained laryngeal elevation and hyoid excursion during larger volume swallows. On the other hand, in the case of bolus expulsion, volume accommodation is accomplished within the same period of time by utilizing increased vigor of expulsion. The result of deglutitive volume accommodation is a remarkably different fluoroscopic appearance of a small vs. a large volume swallow. The larger volume swallow seemingly takes longer and results in much more vigorous bolus expulsion than a small volume. However, this is more related to the bolus than the swallow.     

Reliability and Validity of Cervical Auscultation: A Controlled Comparison Using Video fluoroscopy

Cervical ausculation is experiencing a renaissance as an adjunct to the clinical swallowing assessment. It is a controversial technique with a small evidence base. We have aimed to establish whether cervical ausculation interpretation is based on the actual sounds heard or, in practice, influenced by information gleaned from other aspects of the clinical assessment, medical notes, or previous knowledge. We sought to determine (a) rater reliability and its impact on the clinical value of cervical auscultation and (b) how judgments compare with the “gold standard”: videofluoroscopy. Swallow sounds were computer recorded via a Littmann stethoscope. Sounds were sampled from 10 healthy control swallows with no aspiration/penetration and 10 patient swallows with aspiration/penetration, all recorded during simultaneous videofluoroscopy. The system generated sound quality similar to “live” bedside listening, a feature rarely seen in cervical auscultation studies. The 20 sound clips were classified as “normal” or “abnormal” by 19 volunteer speech-language pathologists with experience in cervical auscultation. After at least four weeks, 11 of these judges rated the sounds rerandomized on a new CD. Intrarater reliability kappa ranged from −0.12 to 0.71. Individual reliability did not correlate with years of experience, practice pattern, or frequency of use. Interrater reliability kappa=0.17. Comparison with radiologically defined aspiration/penetration yielded 66% specificity, 62% sensitivity, and majority consensus gave 90% specificity, 80% sensitivity. There was a significant relationship between individual reliability and true positive rate (r _s=0.623,p=0.040). The reliability of individual judges varied widely and thus, inevitably, agreement between judges was poor. Validity is dependent upon reliability: Improving the poor raters would improve the overall accuracy of this technique in predicting abnormality in swallowing. The group consensus correctly identified 17 of the 20 clips so we may speculate that the swallow sound contains audible cues that shouldin principle permit reliable classification. Study performed at the Freeman Hospital, Newcastle-upon-Tyne, UK. This project was supported by the Stroke Association (grant 11/98). Presented in part at the Otorhinological Research Society, Spring Meeting, 4 April 2003, Birmingham, UK, and the ASHA Convention, 13–15 November 2003.     

Eating and Breathing: Interactions Between Respiration and Feeding on Solid Food

Chewed solid food accumulates in the oropharynx prior to swallowing. The mechanism for preventing aspiration during this interval is unknown, but may be related to respiration. The purpose of this study was to determine how eating, especially bolus formation in the pharynx, affects respiration. We examined nasal air pressures, masseter electromyography (EMG), and videofluorography (VFG) of four normal young adults eating 8 g each of banana and cookie (two trials each food). Resting respiration was recorded for 30 s before eating. Respiratory cycles (RCs) were classified as prefeeding, feeding (excluding cycles with included swallows), and swallowing cycles. RC duration was greater for swallowing than for feeding and prefeeding RCs (P < 0.001). There were up to three swallows in a single RC, but the increase in swallowing RC duration was greater than swallow duration. Swallow apnea began before bolus transport through the hypopharynx and ended as the bolus tail entered the esophagus. There were semirhythmic perturbations in nasal air pressure associated with masseter activity during chewing, suggesting that there was oronasal airflow during jaw closing via the velopharyngeal isthmus. The most important finding was that bolus aggregation in the valleculae usually occurred during an extended plateau in nasal air pressure following active expiration. This suggests that aspiration during eating is prevented by inhibiting respiration during bolus formation in the oropharynx. Supported in part by award #R01-DC02123 from the National Institute on Deafness and other Communication Disorders of the National Institutes of Health.     

Respiratory and Acoustic Signals Associated with Bolus Passage during Swallowing

In order to advance our understanding of the relation between respiration and deglutition, simultaneous videofluoroscopy and respirodeglutometry was performed. Fifteen normal, healthy, young adults (20-29 years of age) were connected to a respirodeglutometer and positioned for simultaneous videofluoroscopic assessment in the lateral plane. Subjects performed three swallows each of a 5-ml and a 10-ml bolus of liquid barium and a 5-ml bolus of paste barium, for a total of nine swallows per subject. Location of the bolus head as identified with videofluoroscopy was associated with eight respirodeglutometric variables. In addition, temporal relations for seven respirodeglutometric variables were calculated as a function of bolus volume and viscosity. Significant temporal differences were found for five of the variables by volume. No significant temporal differences were noted by viscosity. Expiration occurred before 79% and after 96% of the swallows. The number of inspirations preceding a swallow suggested a possible effect resulting from the need to hold a bolus in the mouth before receiving instructions to swallow during videofluoroscopic assessment. This effect may be important during patient evaluation. For a significant number of swallows, respiratory flow ceased before the velum was fully elevated.     

A Pilot Exploratory Study of Oral Electrical Stimulation on Swallow Function following Stroke: An Innovative Technique

This pilot study investigated the effect of oral electrical stimulation on swallow function in stroke patients with chronic dysphagia. The purpose was to determine whether an innovative technique could make an improvement in swallow function that might be developed as a potential treatment for patients with persistent dysphagia. Four stroke patients with chronic dysphagia were recruited on the basis of videofluoroscopic findings of a delayed swallow reflex. A single case design was used. Oral electrical stimulation of swallowing was carried out using a palatal prosthesis starting at an output pulse of 0.5 mA, with a fixed duration of 200 μsec, repeated at 1-sec intervals. Barium paste (1 × 5 ml) was introduced at the level of the patient's maximum tolerance of stimulation and any effect on swallow function was recorded by videofluoroscopy. The findings from the pilot study indicated that oral electrical stimulation resulted in an improvement in swallow function in 2 of the 4 patients. The stimulation was well tolerated in all cases with no serious adverse effects. These early results are promising, but further research is needed.     

Quantitative assessment of swallowing in healthy adults

Swallowing has hitherto been evaluated during physical examination, radiologic barium studies, manometry, and cervical auscultation. Radiography principally demonstrates qualitative aspects of oral and pharyngeal function, whereas quantitative aspects have primarily been documented by manometry. To evaluate swallowing quantitatively, without using invasive methods or radiation, we have applied a combined test of water drinking, i.e., the Repetitive Oral Suction Swallow test (ROSS). The test provides reliable measurements of suction pressure, bolus volume, timing of important events in oral and pharyngeal swallow, and respiration. The test is described and results from 292 healthy, nondysphagic subjects are presented. We found a mean bolus volume of 25.6±8.5 ml during single swallow and 21.1±8.2 ml during stress (forced, repetitive swallow). During forced, repetitive swallow, the bolus volume was more strongly associated with suction time (r²=0.55) than with peak suction pressure (r²=0.04), indicating that suction time is more important than suction pressure in determining the bolus volume. The oral-pharyngeal transit time decreased: single swallow 0.56±0.36 sec, forced repetitive swallow 0.23±0.11 sec, as did the coefficient of variation (48% and 64%, respectively) indicating a more automatic neural process for pharyngeal function in forced, repetitive swallow. The postswallow respiration started with inspiration in 10% of studied individuals, but did not correlate with deviations in other variables in the test. Thus, postswallow inspiration must be considered as normal. The ROSS test offers a rapid and easy quantitative assessment of swallowing.