The Relationship Between Pharyngeal Constriction and Post-swallow Residue.

Shauna L Stokely,Sonja M Molfenter,Chelsea Leigh,Catriona M Steele,Melanie Peladeau-Pigeon

doi:10.1007/s00455-015-9606-5

Abstract

Pharyngeal constriction has been proposed as a parameter that may distinguish functional from impaired swallows. We employed anatomically normalized pixel-based measures of pharyngeal area at maximum constriction, and the ratio of this measure to area at rest, and explored the association between these measures and post-swallow residue using the normalized residue ratio scale (NRRS). Videofluoroscopy data for 5 ml boluses of 22 % (w/v) liquid barium were analyzed from 20 healthy young adults and 40 patients with suspected neurogenic dysphagia. The frames of maximum pharyngeal constriction and post-swallow hyoid rest were extracted. Pixel-based measures of pharyngeal area were made using ImageJ and size-normalized using the squared C2–C4 vertebral distance as a reference scalar. Post-swallow residue and the areas of the vallecular and pyriform sinus spaces were measured on the hyoid rest frame to calculate the NRRSv and NRRSp. The dataset was divided into swallows with residue within or exceeding the upper confidence interval boundary seen in the healthy participants. Mixed model repeated measures ANOVAs were used to compare pharyngeal area (rest, constriction) and the pharyngeal constriction ratio, between individuals with and without residue. Measures of pharyngeal area at maximum constriction were significantly larger (i.e., less constricted, p = 0.000) in individuals with post-swallow residue in either the valleculae or the pyriform sinus. These results support the idea that interventions targeted toward improving pharyngeal constriction have the potential to be effective in reducing post-swallow residue.

Highlights

Pharyngeal constriction has been proposed as a parameter that may distinguish functional from impaired swallows [1,2,3,4,5]
For swallows without residue, measures of pharyngeal area at postswallow hyoid rest occupied approximately 2/3 of the anatomical scalar reference area defined by the squared distance of the C2–C4 vertebral length
Pharyngeal area measures at rest were slightly larger (95 % confidence interval: 70–97 % of the scalar reference area) for swallows displaying residue above the normal limits. When these pharyngeal area measures are entered into the normalized pharyngeal constriction ratio formula, the swallows without residue show almost complete obliteration of the pharynx on maximum constriction, taking up less than 4 % of the corresponding measures at rest

Summary

Introduction

Pharyngeal constriction has been proposed as a parameter that may distinguish functional from impaired swallows [1,2,3,4,5]. Pharyngeal manometry is the gold standard with which to measure the strength of the pharyngeal contraction, it is not readily available in many clinical settings. As an alternative to pharyngeal manometry, Leonard and colleagues developed the ‘Pharyngeal Constriction Ratio’ (PCR), a pixel-based measure made on lateral view videofluoroscopy swallow study (VFSS) frames [2]. The PCR is calculated by tracing the unobliterated area of the pharynx (including the bolus) at the point of maximum constriction during the swallow and dividing that area by a corresponding area measure when the pharynx is at rest. The convention used by Leonard and colleagues is to measure maximum constriction during a.

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