High-resolution manometry of pharyngeal swallow pressure events associated with head turn and chin tuck

Derivation and measurement consistency of a novel biofluid dynamics measure of deglutitive bolus-driving function-pharyngeal swallowing power

BACKGROUND

The primary function of the pharyngeal swallowing mechanism is to drive ingested materials into the esophagus. Currently, a definitive measure of pharyngeal bolus-driving function that accounts for bolus movement remains lacking. The primary objectives of this study were to describe the derivation of a novel biofluid dynamics measure of deglutition-that is, pharyngeal swallowing power (PSP)-and to demonstrate the consistency of PSP in normal swallowing.

METHODS

The pharyngeal swallowing mechanism was conceptualized as a hydraulic power system with the upper esophageal sphincter (UES) as a conduit. PSP was calculated as the product of bolus pressure and flow across the UES. Thirty-four young healthy subjects swallowed materials consisting of two bolus volumes (10, 20 mL) and four bolus viscosities (thin liquid, nectar-thick liquid, honey-thick liquid, pudding). High-resolution impedance manometry was used for data collection. The consistency of PSP across specific bolus conditions was evaluated using standardized Cronbach's coefficient alpha.

KEY RESULTS

Standardized Cronbach's coefficient alphas in specific bolus conditions ranged between 0.85 and 0.93. Fisher weighted mean Cronbach's coefficient alphas for swallow trials across bolus volumes and across bolus viscosities ranged from 0.86 to 0.90. Fisher weighted mean Cronbach's coefficient alpha for overall consistency of PSP across all swallow trials was 0.88.

CONCLUSIONS AND INFERENCES

PSP estimates the output power of the pharyngeal bolus-driving mechanism during deglutition. PSP's high consistency indicates that it can be a useful biofluid dynamics measure of pharyngeal bolus-driving function. Current results also demonstrate that consistency in pharyngeal bolus propulsion is an important physiological target for the pharyngeal swallowing mechanism.

A systematic review of current methodology of high resolution pharyngeal manometry with and without impedance

PURPOSE

This systematic review appraises and summaries methodology documented in studies using high resolution pharyngeal manometry (HRM) with and without impedance technology (HRIM) in adult populations.

METHODS

Four electronic databases CINAHL, EMBASE, MEDLINE, and Cochrane Library were searched up to, and including March 2017. Studies reporting pharyngeal HRM/HRIM for swallowing and/or phonatory assessment, published in peer-reviewed journals in English, German, or Spanish were assessed for the inclusion criteria. Of the selected studies, methodological aspects of data acquisition and analysis were extracted. Publications were graded based on their level of evidence and quality of methodological aspects was assessed.

RESULTS

Sixty-two articles were identified eligible, from which 50 studies reported the use of HRM and 12 studies used HRIM. Of all included manuscripts, the majority utilized the ManoScan™ system (64.5%), a catheter diameter of 4.2 mm was most prevalently documented (30.6%). Most publications reported the application of topical anesthesia (53.2%). For data analysis in studies using HRM, software intrinsic to the recording system was reported most frequently (56%). A minority of the studies using HRM provided data about measurement reliability (10%). This is higher for studies using HRIM (50%).

CONCLUSIONS

Considerable methodological variability exists regarding data acquisition and analysis in published studies using HRM/HRIM. Lacking reports of methodology make study replications difficult and reduce the comparability across studies. More data regarding the impact of individual methodological aspects on study outcomes are further required for the development of methodological recommendations.

SLP-Perceived Technical and Patient-Centered Factors Associated with Pharyngeal High-Resolution Manometry

High-resolution manometry (HRM) objectively measures swallowing-related pressures in the pharynx and esophagus. It has been used in many research applications, but it is unclear how HRM is perceived amongst speech-language pathologists (SLP) as it enters into clinical practice. The purpose of this study was to explore SLP perceptions of clinical HRM use. Based on qualitative data collected at four focus groups held at two national conferences and a survey based on open-ended questions, we found broad consensus among those queried regarding how HRM's objective and targeted data could enhance diagnosis and drive treatments. However, we found less consensus among SLPs regarding which patients may and may not benefit, as well as when in the clinical process HRM would best supplement existing technologies, showing a need for further research. These findings highlight how SLPs can be motivated to adopt new clinical technologies if they see a patient-centered benefit and underscore the need for continued SLP education on pharyngeal HRM.

Correlates of Early Pharyngeal High-Resolution Manometry Adoption in Expert Speech-Language Pathologists

Pharyngeal high-resolution manometry (HRM) is at a point of entry into speech-language pathologist (SLP) clinical practice. However, the demographic characteristics of SLPs who are early adopters of HRM are unclear; perspectives of early adopters may shape how the technology is received by the field at large. We hypothesized that younger SLPs, those working in outpatient settings, those with a strong knowledge base in HRM, and those with experience in other types of instrumentation are more likely to have interest in adopting HRM. We surveyed the population of board-certified SLPs (BCS-S; n = 262) with a 33% response rate (n = 78). Firth logistic regression was used to determine differences in those expressing interest in adopting HRM into future practice (n = 28) and those who did not (n = 45) from the analytic sample of 73 respondents. The best fitting model predicted that SLPs: (1) with training in more types of instrumentation; and (2) believing they could explain the HRM procedure to a patient were more likely to plan to adopt pharyngeal HRM into regular clinical practice. Experience with a variety of instrumentation techniques may encourage SLPs to use new forms of technology. Knowledge of early adopter demographics will allow for development of targeted trainings and determination of HRM implementation barriers. Identification of a clinician sub-group more likely to adopt other new technologies in the future may also be possible.

Defining pharyngeal contractile integral during high-resolution manometry in neonates: a neuromotor marker of pharyngeal vigor

BACKGROUND

Pharyngeal contractility is critical for safe bolus propulsion. Pharyngeal contractile vigor can be measured by Pharyngeal Contractile Integral (PhCI): product of mean pharyngeal contractile amplitude, length, and duration. We characterized PhCI in neonates and examined the hypothesis that PhCI differs with mode of stimulation.

METHODS

Nineteen neonates born at 38.6 (34-41) weeks gestation were evaluated at 42.9 (40.4-44.0) weeks postmenstrual age using high-resolution manometry (HRM). PhCI was calculated using: (a) Conventional and (b) Automated Swallow Detection algorithm (ASDA) methods. Contractility metrics of all pharyngeal regions were examined using mixed statistical models during spontaneous and adaptive state (pharyngeal and oral stimulus) swallowing.

RESULTS

PhCI of oral stimuli swallows were distinct from pharyngeal stimuli and spontaneous swallows (P < 0.05). Correlation between conventional and ASDA methods was high (P < 0.001). PhCI increased with swallows for pharyngeal stimulation (P < 0.05) but remained stable for swallows with oral stimulation. PhCI differed between proximal and distal pharynx (P < 0.001).

CONCLUSIONS

PhCI is a novel reliable metric capable of distinguishing (1) proximal and distal pharyngeal activity, (2) effects of oral and pharyngeal stimulation, and (3) effects of prolonged stimulation. Changes in pharyngeal contractility with maturation, disease, and therapies can be examined with PhCI.

Presentation of oropharyngeal dysphagia and rehabilitative intervention following esophagectomy: a systematic review

No study has systematically reviewed the evidence on presentation of oropharyngeal dysphagia and swallowing rehabilitation following esophagectomy. The purposes of this systematic review are to 1) qualitatively synthesize the current findings on oropharyngeal swallowing abnormalities identified by instrumental swallowing evaluations, 2) describe the reported health-related outcomes in relation to swallowing abnormality following esophagectomy, and 3) examine the efficacy of reported rehabilitative interventions for oropharyngeal dysphagia in patients who underwent esophagectomy. Publications were searched using five electronic databases. No language or publication date restrictions were imposed. Two authors performed a blind review for published or unpublished studies that reported swallowing biomechanics and dysphagic symptoms using instrumental evaluation of swallowing, specifically the videofluoroscopic swallowing study and fiberoptic endoscopic evaluation of swallowing, and/or health-related outcomes in relation to swallowing abnormalities, and/or therapeutic interventions for oropharyngeal dysphagia following esophagectomy. Twelve studies out of 2,193 studies including 458 patients met the inclusion criteria. Reported abnormal swallowing biomechanics included vocal fold immobility, delayed onset of swallowing, reduced hyolaryngeal elevation, and reduced opening of the upper esophageal sphincter. Aspiration (0-81%) and pharyngeal residue (22-100%) were prevalent. Those abnormal swallowing biomechanics and swallowing symptoms were commonly reported following both transhiatal and transthoracic esophagectomy. Pneumonia presented in 5-25% of the study patients. One quasi-experimental study examined the effectiveness of swallowing exercises for postoperative oropharyngeal dysphagia; three case series reported a benefit of the chin-tuck maneuver in reducing aspiration and residue. This review revealed distinct swallowing impairments and increased pneumonia risks following esophagectomy. This review also found that evidence on the efficacy of therapeutic interventions was limited. Future studies are warranted to develop effective rehabilitative interventions for postesophagectomy patients with oropharyngeal dysphagia.

Methods for measuring swallowing pressure variability using high-resolution manometry

Any movement performed repeatedly will be executed with inter-trial variability. Oropharyngeal swallowing is a complex sensorimotor action, and swallow-to-swallow variability can have consequences that impact swallowing safety. Our aim was to determine an appropriate method to measure swallowing pressure waveform variability. An ideal variability metric must be sensitive to known deviations in waveform amplitude, duration, and overall shape, without being biased by waveforms that have both positive and sub-atmospheric pressure profiles. Through systematic analysis of model waveforms, we found a coefficient of variability (CV) parameter on waveforms adjusted such that the overall mean was 0 to be best suited for swallowing pressure variability analysis. We then investigated pharyngeal swallowing pressure variability using high-resolution manometry data from healthy individuals to assess impacts of waveform alignment, pharyngeal region, and number of swallows investigated. The alignment that resulted in the lowest overall swallowing pressure variability was when the superior-most sensor in the upper esophageal sphincter reached half its maximum pressure. Pressures in the tongue base region of the pharynx were least variable and pressures in the hypopharynx region were most variable. Sets of 3 - 10 consecutive swallows had no overall difference in variability, but sets of 2 swallows resulted in significantly less variability than the other dataset sizes. This study identified variability in swallowing pressure waveform shape throughout the pharynx in healthy adults; we discuss implications for swallowing motor control.

Effect of Body Position on Pharyngeal Swallowing Pressures Using High-Resolution Manometry

The effect of body position and gravitational pull on the complex pressure-driven process of pharyngeal swallowing remains unknown. Using high-resolution manometry (HRM), this study aims to identify positional adaptations of pharyngeal physiology by evaluating swallowing pressure patterns in a series of inverted body positions. Ten healthy adults each underwent swallowing tasks with pharyngeal HRM at six body positions using an inversion table (0°[upright], 45°, 90°[supine], 110°, 135°, and 180°[fully inverted]). Repeated measures ANOVA was used to assess impact of position on pressure parameters, and pharyngeal-UES pressure gradients translate. Velopharyngeal pressures varied by position (P < 0.001), with significantly higher pressures generated with inversion ≥90°, compared with upright and 45°. Change in position did not significantly affect common mesopharyngeal pressures or swallowing pressure durations. UES valving mechanisms were preserved during inversion, with subtle variations observed in integral pressures (P = 0.011). Pharyngeal-UES pressure gradients changed with position (P < 0.01), increasing with inversion > 90° compared to upright and 45°. Mechanisms of deglutition may differ with position and relative direction of gravity, particularly when at > 45° inclination. Increased palatal pressure is generated in the upside-down position to achieve nasopharyngeal closure and prevent regurgitation. While other classically measured pressures may not consistently differ with positioning, many individuals exhibit adaptations in pressure gradients when inverted, likely due to a combination of changes in pharyngeal driving force and UES opening mechanisms. Identification of these changes, relative to position, further builds on our understanding of the adaptability of the pharyngeal swallowing system.

Effect of topical nasal anesthetic on swallowing in healthy adults: A double-blind, high-resolution manometry study

OBJECTIVE

Topical nasal anesthetic (TNA) is used when evaluating pharyngeal swallowing with high-resolution manometry (HRM). It is unclear if desensitizing the nasal mucosa improves procedure tolerability or affects pharyngeal pressure. This study evaluated the effects of TNA on comfort and pharyngeal pressure using HRM.

METHODS

A double-blinded study was conducted with 20 healthy participants ( x¯ = 27 years). Participants performed five saliva and five 10-mL swallows during two exams with ManoScan HRM ESO catheter (Medtronic, Minneapolis, MN) randomized under placebo (nonanesthetic lubricant) and anesthetized (0.4 mL of 2% viscous lidocaine hydrochloride) conditions. Comfort was rated using a 100-mm visual analog scale (VAS). Pharyngeal HRM amplitude and timing were analyzed.

RESULTS

VAS ratings were similar under placebo (mean = 38.4, standard deviation [SD] = 19.92) and TNA conditions (mean = 33.78, SD = 18.9), with no significant differences between placebo and anesthetized conditions (t[19] = 1.23, P = 0.23) or tolerability at first and second procedure (t[19] = 1.38, P = 0.18). Lower maximum and mean pharyngeal pressure were found for the TNA condition when compared to placebo (dry: maximum [-15.45 mmHg, standard error (SE) = 5.06 mmHg, P = 0.021]; mean [-5.22 mmHg, SE = 1.58 mmHg, P = 0.005]), and (liquid: maximum [-14.79 mmHg, SE = 5.01 mmHg, P = 0.010]; mean [-2.79 mmHg, SE = 1.99 mmHg, P = 0.008]).

CONCLUSION

This double-blind, randomized study is the first to investigate effects of TNA on tolerability and pharyngeal pressure using HRM. Results indicate TNA offered no significant difference in procedure comfort while affecting the magnitude of pharyngeal swallowing.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1335-1339, 2018.

Characterization of pharyngeal peristaltic pressure variability during volitional swallowing in healthy individuals

BACKGROUND

Recent technological advances incorporated in high resolution manometry have justifiably heightened interest in manometric evaluation of the pharynx. Despite this interest, from both physiologic and clinical perspective there remain a number of unanswered questions regarding the magnitude of variability of pharyngeal pressure phenomena. Therefore, the aim of the present study was to characterize in healthy individuals the inter-subject and recording-site specific variability of pharyngeal peristaltic pressure phenomena.

METHODS

We studied 32 healthy subjects (age: 21-83 years,20 under 35 years) during dry,5 and 10 mL water swallows ×3. Pharyngeal peristaltic pressures were recorded using a high resolution (HR) manometric system and a catheter assembly with 36 circumferential sensors spaced at 1 cm intervals positioned trans-nasally to traverse the pharynx, UES and proximal esophagus.

KEY RESULTS

Both site-specific pressure data and the Pharyngeal contractile integral (PhCI) showed wide dispersion ranging between values under 50 mm Hg to over 300 mm Hg and 100-600 mm Hg/cm/s,respectively. There was also wide range of dispersion of data for both the standard deviations and the coefficient of variation for all sites (P=.001). The coefficient of variation for PhCI ranged between 0.02 and 0.25 representing data dispersion of 2-25 percent of the mean among subjects (P=.001). Position, age and volume of swallowed fluid did not influence the magnitude of variability.

CONCLUSIONS

Deglutitive Pharyngeal peristalsis generates pressures with significant degree of site-related and inter-subject variability. This variability is not influenced by age, position and volume of swallowed fluid.

Quantitative Analysis of Swallowing Function Between Dysphagia Patients and Healthy Subjects Using High-Resolution Manometry

Objective

To compare swallowing function between healthy subjects and patients with pharyngeal dysphagia using high resolution manometry (HRM) and to evaluate the usefulness of HRM for detecting pharyngeal dysphagia.

Methods

Seventy-five patients with dysphagia and 28 healthy subjects were included in this study. Diagnosis of dysphagia was confirmed by a videofluoroscopy. HRM was performed to measure pressure and timing information at the velopharynx (VP), tongue base (TB), and upper esophageal sphincter (UES). HRM parameters were compared between dysphagia and healthy groups. Optimal threshold values of significant HRM parameters for dysphagia were determined.

Results

VP maximal pressure, TB maximal pressure, UES relaxation duration, and UES resting pressure were lower in the dysphagia group than those in healthy group. UES minimal pressure was higher in dysphagia group than in the healthy group. Receiver operating characteristic (ROC) analyses were conducted to validate optimal threshold values for significant HRM parameters to identify patients with pharyngeal dysphagia. With maximal VP pressure at a threshold value of 144.0 mmHg, dysphagia was identified with 96.4% sensitivity and 74.7% specificity. With maximal TB pressure at a threshold value of 158.0 mmHg, dysphagia was identified with 96.4% sensitivity and 77.3% specificity. At a threshold value of 2.0 mmHg for UES minimal pressure, dysphagia was diagnosed at 74.7% sensitivity and 60.7% specificity. Lastly, UES relaxation duration of <0.58 seconds had 85.7% sensitivity and 65.3% specificity, and UES resting pressure of <75.0 mmHg had 89.3% sensitivity and 90.7% specificity for identifying dysphagia.

Conclusion

We present evidence that HRM could be a useful evaluation tool for detecting pharyngeal dysphagia.

Ability of High-Resolution Manometry to Determine Feeding Method and to Predict Aspiration Pneumonia in Patients With Dysphagia

OBJECTIVES

The introduction of high-resolution manometry (HRM) offered an improved method to objectively analyze the status of pharynx and esophagus. At present, HRM for patients with oropharyngeal dysphagia has been poorly studied. We aimed to determine feeding method and predict the development of aspiration pneumonia in patients with oropharyngeal dysphagia using HRM.

METHODS

We recruited 120 patients with dysphagia who underwent both HRM and videofluoroscopic swallow study. HRM was used to estimate pressure events from velopharynx (VP) to upper esophageal sphincter (UES). Feeding methods were determined to non-oral or oral feeding according to dysphagia severity. We prospectively followed patients to assess the development of aspiration pneumonia.

RESULTS

VP maximal pressure and UES relaxation duration were independently associated with non-oral feeding. Non-oral feeding was determined based on optimal cutoff value of 105.0 mm Hg for VP maximal pressure (95.0% sensitivity and 70.0% specificity) and 0.45 s for UES relaxation duration (76.3% sensitivity and 57.5% specificity), respectively. During a mean follow-up of 18.8 months, 15.8% of patients developed aspiration pneumonia. On multivariate Cox regression analysis, VP maximal pressure (P<0.01) and UES relaxation duration (P<0.05) independently predicted the development of aspiration pneumonia. Cumulative incidence of aspiration pneumonia was significantly increased in patients with readings below optimal cutoff values for VP maximal pressure (P<0.01) and UES relaxation duration (P<0.01), individually.

CONCLUSIONS

We first established the optimal thresholds for HRM parameters to determine feeding method and predict the development of aspiration pneumonia in patients with oropharyngeal dysphagia.

Normalization of Temporal Aspects of Swallowing Physiology after the McNeill Dysphagia Therapy Program

Objectives

We examined the timing of physiological swallowing events in patients before and after completion of an exercise-based dysphagia intervention (McNeill Dysphagia Therapy Program; MDTP) and compared their performance to that of healthy volunteers.

Methods

Eight adults (mean age, 57.5 years) with chronic dysphagia (mean, 45 months) completed 3 weeks of the MDTP. Before and after the MDTP we measured lingual-palatal and pharyngeal manometric pressures during swallows of thin liquid, thick liquid, and pudding material in 5-mL volumes. Using the pressure peak of the pharyngoesophageal segment clearing wave as the anchor point, we measured the relative timing of pressure peaks from the anterior, middle, and posterior parts of the tongue and the manometric peaks from the base of the tongue, the hypopharynx, and the nadir of the pharyngoesophageal segment. We compared these results to identical measures obtained from 34 healthy adults (mean age, 44.0 years).

Results

The timing of physiological events before the MDTP was significantly slower than that of the group of healthy volunteers. The timing data from after the MDTP were not significantly different from those of the healthy group. The magnitude change was greatest for thin liquid.

Conclusions

Dysphagia therapy with the MDTP improves the timing of physiological events during swallowing. Temporal coordination of swallowing components after therapy approximates that of healthy adults, suggesting a normalization of swallow timing after the MDTP.

Pharyngeal peristaltic pressure variability, operational range, and functional reserve

The present understanding of pharyngeal motor function remains incomplete. Among the remaining gaps of knowledge in this regard is the magnitude of variability of pharyngeal peristaltic pressure amplitude. Although variability can pose difficulty in interpretation of manometric findings, its magnitude can inform the operational range and reserve of the pharyngeal contractile function. We aimed to define the intra- and intersubject and intersession variability of select pharyngeal manometric parameters and, using this information, determine the number of swallow repetitions for acquiring reliable pharyngeal manometric data. We recorded pharyngeal peristalsis in 10 healthy subjects (age: 50 ± 25 yr, 5 women) by high-resolution manometry during two separate sessions of 20 sequences of 0.5-ml water swallows. Two-way ANOVA showed significant variation in the mean peak peristaltic pressure value across sites (P < 0.0001) as well as within the data at each site (P < 0.0001). Similarly, the pharyngeal contractile integral exhibited significant inter- (P = 0.003) and intrasubject (P < 0.001) variability. The Shapiro-Wilk normality test showed mixed results, in that some sites showed normally distributed data, whereas others did not. A robust Monte Carlo simulation showed that the nominal sample size was different for various tested metrics. For a power of 0.8, commonly accepted as an adequate threshold for acceptable statistical power, the optimal sample size for various peristaltic parameters ranged between 3 and 15. There is significant intra- and intersubject variability in site-specific and integrated parameters of pharyngeal peristalsis. The observed variance indicates a significant operational range and reserve in pharyngeal contractile function while necessitating parameter-specific sample size for reliable results.NEW & NOTEWORTHY Intra- and intersubject variability are significant and different at various sites within the contractile pharynx. In addition, significant swallow-to-swallow and subject-to-subject variability exists in pharyngeal contractile integral. The range of intrasubject variability indicates the existence of broad operational range and reserve. Lastly, our variability studies informed Monte Carlo and power analyses, yielding estimates of sample size that would ensure accurate representation of pressure metric variability.

Pharyngeal swallowing pressures in the base-of-tongue and hypopharynx regions identified with three-dimensional manometry

OBJECTIVES

This study aims to use three-dimensional (3D) high-resolution manometry to identify circumferential pressure patterns generated within the asymmetrical base-of-tongue and hypopharynx regions of the pharynx during deglutition.

STUDY DESIGN

Case series.

METHODS

Radial pressures in the regions of interest were evaluated during swallowing events in 12 healthy subjects using 3D high-resolution manometry.

RESULTS

Repeated measures analysis of variance revealed asymmetrical pharyngeal clearance pressures in the base-of-tongue and hypopharynx regions during swallowing. A significant main effect of direction on pressure was found at the time point of average maximum pressure (P < 0.001) and for pressure integral (P < 0.001), with pressure primarily generated from the posterior direction. An interaction was noted between direction and location when comparing maximum directional pressures, regardless of time (P =0.045), highlighting the differences in anterior pressure production between regions. In contrast to the high posterior pressures produced in the base-of-tongue region, an anteroposterior dominant pressure pattern was observed in the hypopharynx. Pressure waveform complexity in the hypopharynx also is likely attributed to activity in the anterior and posterior directions. Symmetrical pressure generation was observed during intrabolus flow within the hypopharynx.

CONCLUSION

This study shows that pressure is asymmetrically generated in the base-of-tongue and hypopharynx regions during swallowing of a 10-mL bolus, reflecting the complex anatomy within the pharynx. Understanding of these complex pressure patterns aids in the interpretation of high-resolution manometry and can help guide further study in the clinical assessment and treatment of pharyngeal pathology.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:1989-1995, 2017.

Multimodal Swallowing Evaluation with High-Resolution Manometry Reveals Subtle Swallowing Changes in Early and Mid-Stage Parkinson Disease

BACKGROUND

Parkinson disease (PD) has detrimental effects on swallowing function. Treatment options are largely behavioral; thus, patients would benefit from an earlier start to therapy. Early swallowing changes in PD are not well-known, so patients do not typically receive swallowing treatment until later in the progression of PD.

OBJECTIVE

We used predictive modeling to determine what quantitative swallowing variables best differentiate individuals with early to mid-stage PD from healthy controls.

METHODS

Participants included twenty-six individuals with early to mid-stage PD and 26 healthy, age- and sex-matched controls. Swallowing was evaluated by simultaneous high-resolution manometry and videofluoroscopy as well as the Sydney Swallow Questionnaire (SSQ). Binomial logistic regression was performed on 4 sets of data: 1) high-resolution manometry only; 2) videofluoroscopy only; 3) SSQ only; and 4) all data combined.

RESULTS

A model from a combined data set had the highest accuracy in differentiating individuals with PD from controls. The model included maximum pressure in the velopharynx (soft palate), pressure variability in the velopharynx, and the SSQ item concerning difficulty with swallowing saliva. No significant models could be generated using the videofluoroscopy data.

CONCLUSIONS

Individuals with PD show quantitative changes in pressure generation and are able to self-assess aspects of swallowing function in the early and mid-stages of PD, even in the absence of swallowing changes seen on videofluoroscopy. A multimodal approach for the assessment of swallowing may be more accurate for determining subtle swallowing changes that occur in the early stages of PD.

The effectiveness of the head-turn-plus-chin-down maneuver for eliminating vallecular residue

Purpose When swallowing efficiency is impaired, residue accumulates in the pharynx. Cued or spontaneous swallows in the head neutral position do not always successfully clear residue. We investigated the impact of a novel maneuver on residue clearance by combining a head turn with the chin down posture. Methods Data were collected from 26 participants who demonstrated persistent vallecular residue after an initial head neutral clearance swallow in videofluoroscopy. Participants were cued to perform a head-turn-plus-chin-down swallow, with the direction of head turn randomized. Pixel-based measures of residue in the vallecular space before and after the maneuver were made on still frame lateral images using ImageJ software. Measures of % full and the Normalized Residue Ratio Scale (NRRS) were extracted. Univariate analyses of variance were used to detect significant reductions in residue. Results On average, pre-maneuver measures showed residue filling 56-73% of the valleculae, depending on stimulus consistency (NRRS scores: 0.2-0.4). More than 80% of pre-swallow measures displayed NRRS ratios > 0.06, a threshold previously linked to increased risk of post-swallow aspiration. Conclusion The head-turn-plus-chin-down maneuver achieved significant reductions in residue for thin and nectar-thick fluids, suggesting that this maneuver can be effective in reducing persistent vallecular residue with these consistencies.

Therapeutic intervention in oropharyngeal dysphagia

Oropharyngeal dysphagia is a frequent consequence of several medical aetiologies, and even considered part of the normal ageing process. Early and accurate identification provides the opportunity for early implementation of dysphagia treatments. This Review describes the current state of the evidence related to dysphagia therapies - focusing on treatments most clinically utilized and of current interest to researchers. Despite successes in select studies, the level of evidence to support the efficacy of these treatments remains limited. Heterogeneity exists across studies in both how interventions are administered and how their therapeutic value is assessed, thereby making it difficult to establish external validation. Future work needs to address these caveats. Also, to be most efficacious, dysphagia therapies need to account for influences from pre-morbid patient characteristics as these factors have potential to increase the risk of dysphagia and the resulting complications of aspiration, malnutrition and psychological burden. Dysphagia therapies therefore need to incorporate the medical aetiology that is at its root, the resulting swallow physiology captured from comprehensive clinical and/or instrumental assessments, and the existing needs and supports of patients.

Chicago Classification of Esophageal Motility Disorders: Applications and Limits in Adults and Pediatric Patients with Esophageal Symptoms

The Chicago classification (CC) is most valued for its systematic approach to esophageal disorders and great impact in unifying practice for esophageal manometric studies. In view of the ever-growing wealth of knowledge and experience gained by the expanding use of high-resolution manometry (HRM) in various clinical scenarios, the CC is regularly updated. Its clinical impact and ability to predict clinical outcome, both in adults and pediatrics, will be further promoted by recognizing its current limitations, incorporating new metrics in its diagnostic algorithms and adjusting the HRM protocols based on the clinical question posed. Herein, we discuss the current limitations of the CC and highlight some areas of improvement for the future.

Pharyngeal Pressure and Timing During Bolus Transit

Determining intrabolus pressure (IBP) at the upper esophageal sphincter (UES) and in the esophagus has given compelling evidence that IBP can be a predictor for swallowing dysfunction. Studies have looked most superiorly at the low hypopharynx region but there has been no inquiry into what IBP measures throughout the entire pharynx can tell us. We present a study to describe the pressures within and surrounding the moving bolus throughout the pharynx and into the UES. Simultaneous high-resolution manometry (HRM) and videofluoroscopy were performed in ten healthy subjects swallowing ten 10 mL thin-liquid barium boluses. Three events surrounding bolus movement were tracked via videofluoroscopy, and two additional events were found using manometric measures. As the bolus passes through the pharynx, low pressure is created at and below the head of the bolus. A modest pressure increase is seen as the bolus passes through the pharynx, and finally, high pressure is observed at the bolus tail, followed by an even larger pressure generation of a clearance event. HRM allows for greater resolution in data collection in the pharynx and in this study, aided in identifying semi-unique characteristics around the hypopharynx and the UES which are consistent with the complex anatomy of the regions and the transition of the UES from active closure to relaxed opening. In the future, additional studies designed to look at aged and diseased populations may lead to better understanding of disease etiology, and treatment options.

The Effects of Bolus Volume and Texture on Pharyngeal Pressure Events Using High-resolution Manometry and Its Comparison with Videofluoroscopic Swallowing Study

Background/Aims

The purpose of this study was to develop new parameters of high-resolution manometry (HRM) and to applicate these to quantify the effect of bolus volume and texture on pharyngeal swallowing.

Methods

Ten healthy subjects prospectively swallowed dry, thin fluid 2 mL, thin fluid 5 mL, thin fluid 10 mL, and drinking twice to compare effects of bolus volume. To compare effect of texture, subjects swallowed thin fluid 5 mL, yogurt 5 mL, and bread twice. A 32-sensor HRM catheter and BioVIEW ANALYSIS software were used for data collection and analysis. HRM data were synchronized with kinematic analysis of videofluoroscopic swallowing study (VFSS) using epiglottis tilting.

Results

Linear correlation analysis for volume showed significant correlation for area of velopharynx, duration of velopharynx, pre-upper esophageal sphincter (UES) maximal pressure, minimal UES pressure, UES activity time, and nadir UES duration. In the correlation with texture, all parameters were not significantly different. The contraction of the velopharynx was faster than laryngeal elevation. The durations of UES relaxation was shorter in the kinematic analysis than HRM.

Conclusions

The bolus volume was shown to have significant effect on pharyngeal pressure and timing, but the texture did not show any effect on pharyngeal swallowing. The parameters of HRM were more sensitive than those of kinematic analysis. As the parameters of HRM are based on precise anatomic structure and the kinematic analysis reflects the actions of multiple anatomic structures, HRM and VFSS should be used according to their purposes.

Three-dimensional manometry of the upper esophageal sphincter in swallowing and nonswallowing tasks

Objectives/Hypothesis

High‐resolution manometry (HRM) is useful in identifying disordered swallowing patterns and quantifying pharyngeal and upper esophageal sphincter (UES) physiology. HRM is limited by unidirectional sensors and circumferential averaging of pressures, resulting in an imperfect understanding of pressure from asymmetrical pharyngeal anatomy. This study aims to evaluate UES pressures simultaneously from different axial directions.

Study Design

Case series.

Methods

Three‐dimensional HRM was performed on eight healthy subjects to evaluate circumferential UES pressure patterns at rest, during the Valsalva maneuver, and during water swallowing.

Results

Multivariate analysis of the variance revealed a significant main effect of circumferential direction on pressure while at rest (P < .001); pressure was greater in the anterior and posterior portions of the UES versus lateral portions. A significant main effect of direction on pressure was not found during the Valsalva maneuver. During swallowing of a 5‐mL water bolus, circumferential direction had a significant main effect on pressure immediately before UES pressure dropped (P = .001), while the UES was open (P = .01) and at UES closure (P < .001). There was also a significant main effect of sensor level along the vertical axis on pressure immediately before UES pressure dropped (P = .032) and at UES closure (P < .001). Anterior and posterior pressures were again greater than lateral pressures at all swallowing events.

Conclusions

These results confirm that UES pressures vary significantly based on their circumferential origin, with the majority of the total pressure generated in anterior and posterior regions. Improved understanding of UES pressure in a three‐dimensional space can lead to more sophisticated treatments for pharyngeal and UES dysfunction.

Level of Evidence

4. Laryngoscope, 126:2539–2545, 2016

Preliminary Evaluation of Functional Swallow After Total Laryngectomy Using High-Resolution Manometry

INTRODUCTION

Understanding of swallowing pressures after total laryngectomy (TL) and what constitutes a "functional" swallow are limited. Mobile structures are altered or removed after TL, with consequent effects on pressure profiles. High-resolution manometry (HRM) can characterize these pressures.

METHODS

Six TL subjects without dysphagia and 6 controls underwent pharyngeal HRM. Timing and pressure variables for the velopharynx, mesopharynx, and upper esophageal sphincter (UES) were compared. Changes in variables due to bolus volume were evaluated in TL subjects.

RESULTS

The TL subjects had increased duration of velopharyngeal pressure (P = .012). Maximum mesopharyngeal pressure was lower versus controls (P = .003). Maximal and total pre-opening (P = .002, P = .002) and post-closure (P = .001, P = .002) UES pressures were lower. Maximum mesopharyngeal pressure (P = .032) decreased with increasing bolus volume.

CONCLUSIONS

Increased velopharyngeal pressure duration and total swallow duration reflect separation of the pharynx into distinct conduits for air and food, thus ensuring successful bolus passage without the need for respiration. Decreased UES pressure highlights the effects of disrupting the cricopharyngeal and rostral esophageal muscle fibers from their attachments to the larynx and performing a cricopharyngeal myotomy. Additional studies including subjects with dysphagia could further characterize the functional TL swallow and identify aspects susceptible to dysfunction.

A multisensor approach to improve manometric analysis of the upper esophageal sphincter

OBJECTIVES/HYPOTHESIS

High-resolution manometry (HRM) improves on previous manometric systems by including a greater number of sensors that are more densely placed. Due to deglutitive movement of the HRM catheter and upper esophageal sphincter (UES), it is unclear which HRM sensors capture pressure in the UES. To address this issue, we present two complementary studies to describe UES pressure patterns using HRM + videofluoroscopy and HRM + electromyography (EMG).

STUDY DESIGN

Case series involving a new analysis method.

METHODS

Study 1: Simultaneous HRM + videofluoroscopy were performed in 11 healthy subjects swallowing five 10-mL thin-liquid boluses. HRM catheter and UES movement were tracked to identify UES pressure patterns over multiple HRM sensors. Study 2: Simultaneous HRM + cricopharyngeal EMGs were performed in six healthy subjects swallowing five 10-mL water boluses. HRM and EMG outputs were correlated over individual and multiple HRM sensors.

RESULTS

HRM sensors move prior to UES movement (P < .001) and to a lesser extent in rostral and ventral directions (P ≤ .01) than the UES. UES closure pressure is captured with two distinct patterns: 1) a rostral UES pattern with short durations and fast rate of pressure release, depicting UES descent along the catheter as it closes; and 2) a caudal UES pattern with tonic pressures at baseline and a deglutitive nadir. The HRM + EMG multisensor correlation (r = 0.88) was significantly stronger than the single-sensor correlation (r = 0.80; P = .02).

CONCLUSIONS

During deglutition, the HRM catheter and the UES rise above baseline positions and create a distinctive, multisensor manometric trace. Accurate deglutitive UES pressure evaluation must include multiple manometric sensors.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:657-664, 2016.

Propagation Curve and Velocity of Swallowing Pressure in Healthy Young Adults

The objective of this study is to construct a propagation curve and determine propagation velocities in young healthy adults examined using a 2.64-mm-diameter high-resolution manometry catheter with 36 circumferential sensors; to explore data reproducibility; and to determine whether the swallowing pressure (SP) propagation velocity correlated with bolus volume. Repeated measures with subjects serving as their own controls. Thirty healthy subjects (average age 25.3 years) swallowed saliva and 2, 5, and 10 mL of cold water to determine the maximum SP from the soft palate to the cervical esophagus. The SP propagation curve was obtained by plotting the duration to reach each SP peak. The SP propagation velocity was calculated for each region. These parameters were examined according to bolus size and gender. The intra-class correlation coefficient for estimating the SP propagation curves was >0.61 (i.e., highly consistent). The propagation velocity was maximal at the meso-hypopharynx and minimal at the UES and cervical esophagus. The SP propagation curve was very reproducible within any subject. Neither the water volume (with the exception of 2 and 5 mL) nor gender exerted any apparent effect on velocity in any region. However, the velocity was quite variable at the cervical esophagus.

Effects of Head Rotation and Head Tilt on Pharyngeal Pressure Events Using High Resolution Manometry

Objective

To observe changes in pharyngeal pressure during the swallowing process according to postures in normal individuals using high-resolution manometry (HRM).

Methods

Ten healthy volunteers drank 5 mL of water twice while sitting in a neutral posture. Thereafter, they drank the same amount of water twice in the head rotation and head tilting postures. The pressure and time during the deglutition process for each posture were measured with HRM. The data obtained for these two postures were compared with those obtained from the neutral posture.

Results

The maximum pressure, area, rise time, and duration in velopharynx (VP) and tongue base (TB) were not affected by changes in posture. In comparison, the maximum pressure and the pre-upper esophageal sphincter (UES) maximum pressure of the lower pharynx in the counter-catheter head rotation posture were lower than those in the neutral posture. The lower pharynx pressure in the catheter head tilting posture was higher than that in the counter-catheter head tilting. The changes in the VP peak and epiglottis, VP and TB peaks, and the VP onset and post-UES time intervals were significant in head tilting and head rotation toward the catheter postures, as compared with neutral posture.

Conclusion

The pharyngeal pressure and time parameter analysis using HRM determined the availability of head rotation as a compensatory technique for safe swallowing. Tilting the head smoothes the progress of food by increasing the pressure in the pharynx.

The effect of position on esophageal structure and function determined with solid-state high-resolution manometry

OBJECTIVE

To investigate the influence of posture on the anatomy and function of esophageal sphincters using solid-state high-resolution manometry.

METHODS

Fifty individuals underwent esophageal manometry with a 36-channel solid-state catheter in the supine and upright positions. The length and pressure of the esophageal sphincters, as well as the esophageal and intra-abdominal lengths of lower esophageal sphincter (LES), were recorded. The residual pressure of the upper esophageal sphincter (UES) and the 4-s integrated relaxation pressure were also measured when the participants swallowed 10 consecutive servings of water (5 mL each). The Bland-Altman plot was used to assess agreement between these parameters in the supine and upright positions.

RESULTS

The LES resting pressure was significantly decreased in the upright position compared with the supine position (13.85 ± 5.90 mmHg vs 18.09 ± 7.80 mmHg, P = 0.000). Weaker integrated relaxation pressures were observed when the participants were in the upright position (5.66 ± 3.33 mmHg vs 7.80 ± 3.25 mmHg, P = 0.000). Compared with the supine position, the upright esophageal length was longer (P = 0.004) and the upper border of the LES was lower (P = 0.050) when the individuals were in the upright position. The agreement between the two positions was acceptable for the esophageal length, LES upper border location and LES pressure measurements.

CONCLUSIONS

Body position exerts a greater influence on the LES than on the UES. Thus, it is necessary to establish normal values for the LES basal pressure and residual pressure in different positions.

Upper esophageal sphincter resting pressure varies during esophageal manometry

Background

The upper esophageal sphincter is composed of striated muscle. The stress of intubation and the need to inhibit dry swallows during an esophageal manometry test may lead to variations in basal pressure of this sphincter. Upper esophageal sphincter is usually only studied at the final part of the test. Was observed during the performance of high resolution manometry that sphincter pressure may vary significantly over the course of the test.

Aim

To evaluate the variation of the resting pressure of the upper esophageal sphincter during high resolution manometry.

Methods

Was evaluated the variation of the basal pressure of the upper esophageal sphincter during high resolution manometry. Were reviewed the high resolution manometry tests of 36 healthy volunteers (mean age 31 years, 55% females). The basal pressure of the upper esophageal sphincter was measured at the beginning and at the end of a standard test.

Results

The mean time of the test was eight minutes. The basal pressure of the upper esophageal sphincter was 100 mmHg at the beginning of the test and 70 mmHg at the end (p<0.001). At the beginning, one patient had hypotonic upper esophageal sphincter and 14 hypertonic. At the end of the test, one patient had hypotonic upper esophageal sphincter (same patient as the beginning) and seven hypertonic upper esophageal sphincter.

Conclusion

A significant variation of the basal pressure of the upper esophageal sphincter was observed in the course of high resolution manometry. Probably, the value obtained at the end of the test may be more clinically relevant.

Implementation of high-resolution manometry in the clinical practice of speech language pathology

Visual imaging modalities, videofluoroscopic swallow study (VFSS) and fiberoptic endoscopic evaluation of swallow, for assessment of oropharyngeal dysphagia have been part of the speech language pathologist's (SLPs) armamentarium for the diagnosis and treatment of dysphagia for decades. Recently, the addition of high-resolution manometry (HRM) has enabled the SLP to evaluate pharyngeal pressures and upper esophageal sphincter relaxation. Taken together, the use of visual imaging modalities with HRM can improve interpretation of swallowing physiology and facilitate more effective treatment planning. The goal of this article is to describe a clinical paradigm using HRM as an adjunct to VFSS, by the SLP, in the assessment of complex dysphagia. Moreover, in three cases described, the value of manometric measurements in elucidating swallowing imaging studies and documenting physiologic change in response to treatment is highlighted. As technology in this area is evolving, so will the clinical use of HRM by the SLP. Limitations of current HRM systems and applications are discussed.

Application and Interpretation of High-resolution Manometry for Pharyngeal Dysphagia

The pharyngeal phase of swallowing is a complex event consisted with subsequent muscular contractions and pressure generation to move a bolus from the mouth to the esophagus. Recently, high-resolution impedance manometry (HRIM) was developed and used for the evaluation of pharyngeal dysphagia. Although HRIM provides precise pharyngeal pressure information, it has yet to be used as part of routine clinical practice for the assessment of dysphagia. The main reasons are thought to be that the test method and result interpretation are not easily applicable and standardized. The anatomical landmarks for HRIM parameters are velopharynx, tongue base, epiglottis, low pharynx, and upper esophageal sphincter. With HRIM, the pressure and timing data could be obtained at a precise anatomical structure. In the present review, we will review how to apply HRIM for the evaluation of pharyngeal dysphagia, including the interpretation of its parameters.

Influence of the chin-down and chin-tuck maneuver on the swallowing kinematics of healthy adults

The purpose of the study was to investigate the influence of the chin-tuck maneuver on the movements of swallowing-related structures in healthy subjects and formulate standard instructions for the maneuver. A total of 40 healthy volunteers (20 men and 20 women) swallowed 10 mL of diluted barium solution in a “normal and comfortable” position (NEUT), a comfortable chin-down position (DOWN), and a strict chin-tuck position (TUCK). Resting state anatomy and kinematic changes were analyzed and compared between postures. Although angles of anterior cervical flexion were comparable between DOWN (46.65 ± 9.69 degrees) and TUCK (43.27 ± 12.20), the chin-to-spine distance was significantly shorter in TUCK than in other positions. Only TUCK showed a significantly shorter anteroposterior diameter of the laryngeal inlet (TUCK vs. NEUT, 14.0 ± 4.3 vs. 16.3 ± 5.0 mm) and the oropharynx (18.8 ± 3.1 vs. 20.5 ± 2.8 mm) at rest. The maximal horizontal displacement of the hyoid bone was significantly less in TUCK (9.6 ± 3.0 mm) than in NEUT (12.6 ± 2.6 mm; p < 0.01) or DOWN (12.1 ± 3.0 mm; p < 0.01). TUCK facilitated movement of the epiglottic base upward (TUCK vs. NEUT, 15.8 ± 4.7 vs. 13.3 ± 4.5 mm; p < 0.01). In contrast, DOWN increased the horizontal excursion of the epiglottic base and reduced movement of the vocal cords. These results quantitatively elucidated the biomechanical influences of the chin-tuck maneuver including reduced horizontal movement of the hyoid bone, facilitation of vertical movement of the epiglottic base, and narrowing of the airway entrance. Comparing DOWN and TUCK, only TUCK induced significant changes in the airway entrance, hyoid movement, and epiglottic base retraction.

Quantifying contributions of the cricopharyngeus to upper esophageal sphincter pressure changes by means of intramuscular electromyography and high-resolution manometry

OBJECTIVES

We sought to determine whether the association between cricopharyngeus muscle activity and upper esophageal sphincter pressure may change in a task-dependent fashion. We hypothesized that more automated tasks related to swallow or airway protection would yield a stronger association than would more volitional tasks related to tidal breathing or voice production.

METHODS

Six healthy adult subjects underwent simultaneous intramuscular electromyography of the cricopharyngeus muscle and high-resolution manometry of the upper esophageal sphincter. Correlation coefficients were calculated to characterize the association between the time-linked series.

RESULTS

Cricopharyngeus muscle activity was most strongly associated with upper esophageal sphincter pressure during swallow and effortful exhalation tasks (r = 0.77 and 0.79, respectively; P < .01). The association was also less variable during swallow and effortful exhalation.

CONCLUSIONS

These findings suggest a greater coupling for the more automatic tasks, and may suggest less coupling and more flexibility for the more volitional, voice-related tasks. These findings support the important role of central patterning for respiratory- and swallow-related tasks.

Impact of Neuromuscular Electrical Stimulation on Upper Esophageal Sphincter Dynamics

Objectives:

Beside traditional dysphagia therapy, neuromuscular electrical stimulation (NMES) has been proposed to treat patients with dysphagia. Considering the complexity of the nerve-muscle interaction during swallowing, the underlying physiology of NMES remains unclear. Here, we addressed the question of whether NMES can modify upper esophageal sphincter (UES) dynamics.

Methods:

In a prospective study, 26 healthy volunteers performed water swallows with and without NMES. The stimulus was applied in a participant- and operator-initiated stimulation above, near, and below the motor threshold. Swallowing parameters were measured using high-resolution manometry.

Results:

The UES relaxation time was found to be extended by 10%, indicating a modification in UES dynamics.

Conclusions:

The chosen NMES paradigm influenced the involuntary swallowing phase by extending relaxation time, providing more time for bolus passage into the esophagus. Future studies will have to evaluate if this effect can be found in patients with dysphagia and whether it is beneficial for treatment.

Reliability of an automated high-resolution manometry analysis program across expert users, novice users, and speech-language pathologists

PURPOSE

The purpose of this study was to investigate inter- and intrarater reliability among expert users, novice users, and speech-language pathologists with a semiautomated high-resolution manometry analysis program. We hypothesized that all users would have high intrarater reliability and high interrater reliability.

METHOD

Three expert users, 15 novice users, and 5 speech-language pathologists participated in this study. Following a 20-min training session, users analyzed 30 high-resolution manometry plots using an automated analysis program. Output parameters included 2- and 3-dimensional pressure integrals over 5 anatomical regions of interest. Intraclass correlations were used to examine inter- and intrarater reliability. An analysis of variance was also performed to determine any differences in mean output parameter values.

RESULTS

Within-group interrater reliability ranged from 0.54 to 0.99, and intergroup reliability ranged from 0.92 to 0.99. Intrarater reliability ranged from 0.67 to 1.00 across all groups. There were no significant differences of output parameters among groups.

CONCLUSIONS

The high reliability observed after a short training session demonstrates that individuals with little to no prior knowledge of swallowing physiology can perform at a similar level as those with expertise. Given the quickness and ease of training in the use of this program, it has the potential for research and clinical utility.

Botulinum toxin for upper oesophageal sphincter dysfunction in neurological swallowing disorders

BACKGROUND

Adequate upper oesophageal sphincter (UOS) opening is critical to safe and efficient swallowing due to the close proximity of the UOS to the airway entrance. Many people with neurological conditions, progressive and non-progressive, present with UOS dysfunction. The consequences for the person include difficulty swallowing food with subsequent choking and aspiration (passage of material into the trachea beyond the level of the true vocal cords). Clinical complications include aspiration pneumonia, weight loss, dehydration and malnutrition. Tube feeding is often indicated but is associated with increased mortality. Quality of life is also frequently impacted. A range of interventions exist that aim to improve UOS function and swallowing. These include compensatory strategies, rehabilitation techniques, pharmacological interventions and surgery. Over the last two decades, botulinum toxin has been gaining popularity as an intervention for UOS dysfunction, with some evidence to suggest that it is successful in improving swallow function. Despite a number of studies investigating its efficacy, there is a lack of consensus regarding whether this intervention is effective in improving swallowing for individuals with UOS dysfunction associated with neurological disease.

OBJECTIVES

To establish the efficacy and safety of botulinum toxin use aimed at improving UOS dysfunction in people with swallowing difficulties (dysphagia) associated with non-progressive and progressive neurological disease.

SEARCH METHODS

We searched the following electronic databases for published trials: the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (1950 to 2013); EMBASE (1980 to 2013); AMED (Allied and Complementary Medicine) (1941 to 2013); CINAHL (Cumulative Index to Nursing and Allied Health Literature) (1937 to 2013). We also searched major clinical trials registers: CCT (http://www.controlled-trials.com); Clinical Trials (http://www.clinicaltrials.gov); Chinese Clinical Trial Register (www.chictr.org); ACTR (http://www.actr.org.au/. We examined the reference lists of all potentially relevant studies to identify further relevant trials. We handsearched published abstracts of conference proceedings from both the Dysphagia Research Society and the European Society of Swallowing Disorders. Digestive Disease Week (published in Gastroenterology) was also handsearched. Additionally, we searched ProQuest Dissertations & Theses for dissertation abstracts.

SELECTION CRITERIA

Only randomised controlled trials were sought.

DATA COLLECTION AND ANALYSIS

Independent searches were completed by JR, AM, MC and MW. Two review authors (JR and MW) independently inspected titles, abstracts and key words identified from the literature search.

MAIN RESULTS

No randomised controlled studies were retrieved. Twenty-nine studies were excluded, mainly on the basis of trial design.

AUTHORS' CONCLUSIONS

It was not possible to reach a conclusion on the efficacy and safety of botulinum toxin as an intervention for people with UOS dysfunction and neurological disease. There is insufficient evidence to inform clinical practice. Directions for future research are provided.

Effect of bolus volume on pharyngeal swallowing assessed by high-resolution manometry

OBJECTIVE

Solid-state high-resolution manometry (HRM) is fast becoming the gold standard for studying pharyngeal and esophageal motility. However, very few studies have ever evaluated the effect of bolus volume on the physiology of swallowing using HRM. We aimed to determine the effect of bolus volume on pressure, duration and velocity of the hypopharynx as well as the upper esophageal sphincter during pharyngeal swallowing using HRM.

METHODS

Thirty-four healthy subjects completed nine swallows (3 ml, 5 ml and 10 ml of water, thick liquid, and paste, respectively) in the natural sitting position. Pressure and duration measurements were acquired from the hypopharynx and upper esophageal sphincter (UES) using HRM. The UES residual pressure, UES relaxation duration, maximum preopening UES pressure, maximum postclosure UES pressure, maximum hypopharyngeal pressure, maximum hypopharyngeal pressure rise rate and hypopharyngeal pressure duration were analyzed across bolus volumes using repeated measures of one-way analysis of variance.

RESULTS

A significant increase in UES residual pressure associated with increased bolus volume during water and paste swallowing was observed. Furthermore, UES relaxation duration was significantly increased with increasing in bolus volume for all three material swallows. No significant volume effects were found on the hypopharynx.

CONCLUSIONS

In summary, bolus volume has a significant effect on the residual pressure and relaxation duration, but no effect on maximum preopening pressure or maximum postclosure pressure of the UES. Maximum hypopharyngeal pressure, maximum hypopharyngeal pressure rise rate and pressure duration were also not affected by bolus volume. Consideration of these variables is paramount in understanding normal and pathological swallowing.