Decoupling of biomechanics of hyoid movement and bolus flow in preterm infants

Abstract

Determining the timing of bolus passage over the airway, and into the esophagus, is critical for biomechanical studies of swallowing. Videofluroscopy is the gold standard for determining fluid movement, but is not always possible. Hylolaryngeal movement, measured from light film or standard videography, is a reliable marker for adult human swallowing, but its validity for the biomechanics of swallowing in immature infants is unknown. We tested the relationship between hyolaryngeal movement from light camera data compared to bolus movement from video fluoroscopy in pre‐term and term infant pigs.Three term and four pre‐term pigs were fed from a bottle containing barium and a milk solution. At seven days after birth pigs were recorded feeding from the bottle using simultaneous high speed (100 fps) x‐ray and light video cameras. In the light video, the frame of most rapid elevation of the hyoid was scored as the swallow. In the x‐ray, the swallows were scored as the beginning of posterior bolus movement. The number of frames separating x‐ray and light camera swallow identifications was calculated for each swallow.Hyoid movement was found to be closely correlated to bolus movement in term pigs, but no correlation existed in pre‐term pigs. The mean frame offsets for term and pre‐term pigs were different (Wilcox test, p<0.001). The variance for the pre‐term pigs was significantly larger (Levene's test p<0.001).The light videos were found to be a good measure of swallows in term pigs, but were not a good measure of swallows in pre‐term pigs. The biomechanics of bolus movement are altered in the neurologically poorly coordinated pre‐term pigs. Specifically, hyolaryngeal elevation and bolus movement are decoupled in pre‐terms whereas they are tightly coordinated in term pigs. Prematurity leads to altered form function relationships through immature development.Support or Funding InformationNICHD grant 088561This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.