[High-resolution manometry of the upper esophageal sphincter]

Potential for Behavioural Pressure Modulation at the Upper Oesophageal Sphincter in Healthy Swallowing

Supratentorial structures are known to be involved in the neural control of swallowing, thus the potential for volitional manipulation of pharyngeal swallowing is of rehabilitative interest. The extent of volitional control of the upper oesophageal sphincter (UOS) during swallowing remains unclear. Prior research has shown that the UOS opening duration can be volitionally prolonged during execution of the Mendelsohn manoeuvre, which does not change the UOS opening time in isolation but the swallowing response in its entirety. This study explored the capacity of healthy adults to increase the period of pressure drop in the region of the UOS (UOS-Pdrop) during swallowing, through volitional UOS pressure modulation in the absence of altered pharyngeal pressure. The period of UOS-Pdrop was used as a proxy of UOS opening duration that is associated with a pressure decrease at the region of the UOS. Six healthy adults were seen 45 min daily for 2 weeks and for one follow-up session. During training, high-resolution manometry contour plots were provided for visual biofeedback. Participants were asked to maximally prolong the blue period on the monitor (period of UOS-Pdrop) without altering swallowing biomechanics. Performance was assessed prior to training start and following training. There was evidence within the first session for task-specific volitional prolongation of the period of UOS-Pdrop during swallowing with biofeedback; however, performance was not enhanced with further training. This may suggest that the amount to which the period of UOS-Pdrop may be prolonged is restricted in healthy individuals. The findings of this study indicate a potential of healthy adults to volitionally prolong UOS opening duration as measured by the period of pressure drop at the region of the UOS. Further research is indicated to evaluate purposeful pressure modulation intra-swallow in patient populations with UOS dysfunction to clarify if the specificity of behavioural treatment may be increased.

[High-resolution manometry of pharyngeal swallowing dynamics]

BACKGROUND

To transport a bolus from the mouth into the stomach, regular contraction of the pharyngeal muscles and a coordinated function of the upper esophageal sphincter (UES) are necessary. The muscle contraction generates intraluminal pressure, which pushes the bolus continuously forward. In contrast to imaging studies, manometric methods enable assessment of intraluminal pressure buildup and the function of the muscles involved. These methods were initially established for the esophagus and have been used increasingly in the pharynx for 7-8 years. Pharyngeal high-resolution manometry (pHRM) allows pressure measurements in high spatial and temporal resolution, and assessment of pharyngeal swallowing dynamics.

OBJECTIVE

An overview is given of the implementation, evaluation, and interpretation of the pHRM data, as well as of the current state of research.

MATERIALS AND METHODS

PubMed and Scopus were searched for the keywords "high-resolution manometry" and "pharynx" or "upper esophageal sphincter". Original articles, reviews, and book chapters on the subject pHRM were included.

RESULTS

Swallowing pressure conditions in the pharynx and the UES can be assessed by pHRM. The spatiotemporal pressure plot gives an overview of changes in pharyngeal motor function. Determination of swallowing parameters enables a sophisticated evaluation of swallowing; a comparison with normal values permits delimitation of pathologies.

CONCLUSION

Although several swallowing parameters still need to be further evaluated for clinical routine, a pHRM study should nowadays always be carried out for a comprehensive evaluation of the swallowing process.

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.

[High resolution manometry study of pharyngeal function in patients with myotonic dystrophy]

BACKGROUND

Patients with myotonic dystrophy (MD) are known to suffer from oropharyngeal dysphagia and esophageal motility disorders, which are often the cause of aspiration pneumonia. So far only little is known about the pharyngeal contractility and the function of the upper esophageal sphincter in these patients, in particular only few data are available for manometric investigations allowing assessment of the pharyngeal pressure build-up during swallowing. The aim of this study was to collect such data in patients with MD using high resolution manometry.

METHOD

In two patients with MD high resolution manometry studies were performed during swallowing and phonation to determine pressure-dependent parameters. The results were compared with normal values from healthy subjects.

RESULTS

In both patients a reduced pressure in the entire pharynx during swallowing was determined. The duration of the contraction in the velopharynx and tongue base region was shortened. The structural course of the swallowing process and the opening and closing functions of the upper esophageal sphincter were regular. During realization of closed vowels a reduced pressure build-up in the velopharyngeal region was observed.

CONCLUSION

The force of contraction and the associated pharyngeal pressure build-up during swallowing were reduced resulting in an incomplete clearing of the pharynx. Beside myopathic disorders, neuromuscular disorders also have to be considered. The functional course of the swallowing process and the swallowing pattern was retained. The reduced pressure build-up in the velopharyngeal region can be considered as the cause for rhinophonia. To evaluate the pharyngeal function in patients with MD, high resolution manometry is a useful tool for assessing the pharyngeal function besides the basic diagnostics.

[Physiology of the upper esophageal sphincter]

The upper esophageal sphincter (UES) forms a barrier between the pharynx and the esophagus. When opened, the UES allows the food bolus to pass into the esophagus, as well as permitting emesis and eructation. The basal sphincter tone constitutes a barrier function which serves to prevent reflux and passive aerophagia in the case of deep breathing. Basal sphincter tone is dependent on several influencing factors; during swallowing, sphincter opening and closure follow a complex multiphase pattern. This article presents an overview of the current understanding of UES physiology.