Susan McKenzie

Structural mobility in deglutition after single modality treatment of head and neck carcinomas with radiotherapy

The results of a preliminary study designed to evaluate swallowing function in patients 1 year after successful treatment of head and neck carcinomas with radiotherapy are reported.

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.

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.

Timing of Swallowing Events after Single-Modality Treatment of Head and Neck Carcinomas with Radiotherapy

This paper reports the results of a preliminary study designed to evaluate swallowing function in 20 patients 1 year after successful treatment of head and neck carcinomas with radiotherapy. The timing of swallowing events was evaluated by videofluoroscopy. The mean values for each measure were compared to the normative data from 60 control subjects. The radiotherapy patients demonstrated prolonged pharyngeal bolus transit and a delay of laryngeal closure. Hyoid bone elevation began late relative to the onset of bolus movement. A strong trend toward a delay in hyoid elevation relative to bolus movement was demonstrated. The time required for the hyoid bone to reach maximal elevation did not differ from that in normals, but the hyoid was held in an elevated position for a longer period of time. As a result of changes in hyoid movement, the upper esophageal sphincter tended to open early relative to the arrival of the bolus. In conclusion, changes in deglutition occur after radiotherapy, presumably as an adaptation to changes in tissue compliance.

Structural displacements affecting pharyngeal constriction in nondysphagic elderly and nonelderly adults.

This study investigated spatial displacement variables important to pharyngeal constriction and clearing in nondysphagic elderly subjects and a control group of nondysphagic younger adults. Height, weight, and body mass index (BMI) characteristics were determined for all subjects, who then underwent videofluoroscopic swallow studies. Measures obtained during swallow of a 20-cc bolus included hyoid and laryngeal displacement, unobliterated pharyngeal space at the point of maximum pharyngeal constriction, and pharyngeal width when maximally expanded during the swallow. Data were first examined to determine if elderly subjects with medical conditions common to an aged population differed from elderly subjects with no medical condition. No differences were identified and data for all elderly subjects were subsequently pooled for comparison to data for the nonelderly control group. Findings revealed no differences in maximum hyoid displacement between the groups. Significant differences were identified for larynx-to-hyoid approximation and for the measure representing unobliterated pharyngeal space at the point of maximum pharyngeal constriction. Elderly subjects did not elevate the larynx to the same extent, or clear the pharynx, as well as the younger control subjects. In addition, data suggested that the larynx was positioned lower and that the width of the pharynx maximally expanded was greater in elderly subjects. Implications of the data for swallowing function in the elderly are discussed.

Accommodation to Changes in Bolus Viscosity in Normal Deglutition: A Videofluoroscopic Study

Videofluoroscopic swallow studies were performed on 60 normal adult volunteers. Swallowing variables were measured during swallows of a 3-cm3 paste bolus and a 3-mL liquid bolus and were compared to identify changes in swallow gesture displacement and timing, as well as changes in bolus movement timing. The study revealed that some differences measured by videofluoroscopy appear to be the result of the inherent bolus characteristics, while others likely represent changes in swallow gestures needed to accommodate variations in bolus viscosity. The overall timing of pharyngeal transit did not vary between bolus types. Oropharyngeal transit trended toward being faster for a liquid bolus with a concurrent early elevation of the aryepiglottic folds. The hyoid bone elevated at the same time, at the same rate, and to the same extent irrespective of bolus viscosity. During a liquid bolus swallow, the hyoid bone trended toward a more prolonged elevation, corresponding to prolonged pharyngoesophageal sphincter opening. The pharyngoesophageal sphincter, however, opened to a greater extent with a paste bolus.

Common medical conditions in the elderly: impact on pharyngeal bolus transit.

Deglutition in the elderly may be impacted by the sequelae of medical diseases. It is unknown if the long-term presence of common medical diseases, such as arthritis and hypertension, leads to changes in neurologic and muscular function and thus swallowing ability. The aim of this project was to determine if the duration of bolus pharyngeal transit in nondysphagic elderly individuals with chronic medical problems is longer than that measured in nondysphagic elderly individuals without medical problems. Videofluoroscopic swallowing studies were performed on 63 elderly subjects with a variety of well-controlled medical problems and on 23 elderly subjects with no medical problems. The mean timing of pharyngeal bolus transit was compared between the two groups. The relationship between the presence of medical problems and the likelihood of transit times prolonged beyond two standard deviations of the mean transit time found in 60 younger normal controls was also analyzed. Findings included significantly prolonged pharyngeal transit time in the group of subjects with medical problems compared with those subjects without medical problems for a small bolus size. Those individuals with hypertension demonstrated the most significant delays in bolus transit. The presence of medical problems did correlate with an increased likelihood of prolonged transit times. This preliminary study indicates that medical problems common in elderly populations are associated with a deterioration of swallowing function and that changes identified in elderly individuals may not be due to aging alone.

Sequence variability during hypopharyngeal bolus transit.

The pharyngeal phase of deglutition is considered to occur in a reflexive, preprogrammed fashion. Previous studies have determined a general sequence of events based on the mean timing of bolus transit and swallowing gestures. Individual variability has not been studied, however. The purpose of this study was to determine the amount of sequence variability that normally occurs during the hypopharyngeal phase of deglutition. Dynamic swallow studies from 60 normal volunteers were evaluated and event sequence variability was determined for 12 two-event sequences during swallowing of three bolus sizes. There was found to be some variability in event sequences for almost all events evaluated except for the following : (1) arytenoid cartilage elevation always began prior to opening of the upper esophageal sphincter, (2) the sphincter always opened prior to the arrival of the bolus at the sphincter, (3) larynx-to-hyoid approximation always occurred after the onset of upper esophageal sphincter opening, and (4) maximum pharyngeal constriction always occurred after maximal distension of the upper esophageal sphincter. Variability was more common during swallowing of the smallest bolus size. This information may be helpful in evaluating event coordination in patients with dysphagia.

Effects of Bolus Rheology on Aspiration in Patients with Dysphagia

Bolus manipulation is a primary treatment strategy in the management of oral-pharyngeal dysphagia. The use of thickening agents to alter bolus rheology is particularly commonplace; however, the precise effects of these alterations on swallowing remain uncertain. The purpose of our study, a prospective, double-blind clinical trial (Level 1b), was to investigate the effects of viscosity on aspiration. One hundred patients with dysphagia were prospectively evaluated with fluoroscopic swallow studies performed across three standardized and randomized conditions: thin liquid barium (THIN), liquid barium thickened with a starch-based agent (STARCH), and liquid barium thickened with a gum-based agent (GUM). Outcome measures included the prevalence of aspiration and score on the Penetration-Aspiration Scale. A total of 23 out of 100 patients exhibited 56 episodes of aspiration. Twenty patients aspirated on THIN, 15 on STARCH, and 11 on GUM bolus conditions (P<0.05, thin vs gum). There were 28 instances of aspiration on THIN, 16 on STARCH, and 12 on GUM. Mean Penetration-Aspiration Scale score ± standard deviation was 2.11 ± 2.22 for THIN, 1.76 ± 1.88 for STARCH, and 1.42 ± 1.47 for GUM conditions, respectively (P<0.001, THIN vs GUM). A clinically significant reduction in the incidence of penetration and aspiration was observed for gum-thickened barium compared with thin liquid barium.

Hyoid-bolus transit latencies in normal swallow

Pharyngeal swallow delay is frequently found in dysphagic patients and is thought to be a factor in a range of swallowing problems, including aspiration. Implicit in notions of swallow “delay” is a temporal interval between two events that is longer than normal. However, there appears to be little agreement about which referent events should be considered in determining delay. A number of pharyngeal bolus transit points and various pharyngeal gestures have been used in delays determined from fluoroscopic evidence, and other referents have been used in electromyographic and manometric studies of swallow. In this study latencies between the first movement of the hyoid and several pharyngeal bolus transit points were calculated from fluoroscopic swallow studies in normal nondysphagic adults. Means and standard deviations of these latencies are provided for a 3-cc and a 20-cc bolus and for both nonelderly and elderly adults. The data may be a useful resource for relating the specific latencies investigated to concepts of pharyngeal swallow delay, in particular, when assessing videofluoroscopic studies using a similar protocol.