Pharyngeal Swallowing Mechanics Secondary to Hemispheric Stroke

Abstract

Goals Computational Analysis of Swallowing Mechanics is a method that utilizes multivariate shape change analysis to uncover covariant elements of pharyngeal swallowing mechanics associated with impairment using videofluoroscopic swallowing studies. The goals of this preliminary study were to (1) characterize swallowing mechanics underlying stroke related dysphagia, (2) decipher the impact of left and right hemispheric stroke on pharyngeal swallowing mechanics, and (3) determine pharyngeal swallowing mechanics associated with penetration-aspiration status. Materials and Methods Videofluoroscopic swallowing studies of 18 dysphagic patients with hemispheric infarcts and age and gender matched controls were selected from well-controlled data sets. Patient data including laterality, and penetration-aspiration status was collected. Coordinates mapping muscle group action during swallowing were collected from videos. Multivariate morphometric analyses of coordinates associated with stroke, affected hemisphere, and penetration-aspiration status were performed. Findings Pharyngeal swallowing mechanics differed significantly in the following comparisons: stroke vs. controls (D=2.19, p<.0001); right hemispheric stroke vs. controls (D=3.64, p<.0001); left hemispheric stroke vs. controls (D=2.06, p<.0001); right hemispheric stroke vs. left hemispheric stroke (D=2.89, p<.0001); and penetration-aspiration vs. within normal limits (D=2.25, p<.0001). Differences in pharyngeal swallowing mechanics associated with each comparison were visualized using eigenvectors. Conclusion While current literature focuses on timing changes in stroke-related dysphagia, this data suggests that mechanical changes are also functionally important. Pharyngeal swallowing mechanics differed by affected hemisphere and penetration-aspiration status. Computational Analysis of Swallowing Mechanics can be used to identify patient specific swallowing impairment associated with stroke injury that could help guide rehabilitation strategies to improve swallowing outcomes.

Pharyngeal swallowing mechanics associated with upper esophageal sphincter pressure wave

“…Then, for each frame, the x-and y-coordinates of each landmark were recorded until the bolus passed into the esophagus and the pharynx returned to its resting position. These landmarks (except #13) have been previously described 15,17,18 and represent anatomic structures underlying functional changes during swallowing including soft palate elevation and retraction, hyoid movement, laryngeal elevation, pharyngeal shortening, tongue base retraction, and pharyngeal constriction. The first author previously met reliability criterion for coordinate mapping (interrater r > .95 for all coordinates) and collected all coordinate points using the MATLAB (Mathworks, Natick, Massachusetts) CASM tool.…”

Taste Manipulation and Swallowing Mechanics in Trauma-Related Sensory-Based Dysphagia

“…To further examine the oropharyngeal swallowing physiology associated with taste trials, a subset of swallow events was analyzed using CASM (May et al, 2017). Trial selection for this analysis was based on (a) availability of an unflavored (baseline), sour, and sweet-sour trial from the same date and participant in order to control for subject morphology in a small data set and (b) VFSS collimation that included all anatomical structures required for the analysis in all three trials from that participant.…”

Clinical Application of Flexible Endoscopic Evaluation of Swallowing in Stroke

“…[49][50][51][52] Individuals with right hemisphere strokes have been shown to have a more impaired swallow than those with left-sided strokes when compared with controls. 51,[53][54][55] Further, those with right hemisphere strokes have demonstrated significantly reduced hyoid excursion, reduced tongue-base retraction, increased neck flexion, and posterior positioning of the larynx. 53 For videofluoroscopy studies, objective measures are established to quantify and characterize deficits, such as oral and pharyngeal transit time and hyolaryngeal elevation during videofluoroscopy.…”