Preterm Birth Impacts the Timing and Excursion of Oropharyngeal Structures during Infant Feeding

Abstract

Swallowing in mammals requires the precise coordination of multiple oropharyngeal structures, including the palatopharyngeal arch. During a typical swallow, the activity of the palatopharyngeus muscle produces pharyngeal shortening to assist in producing pressure required to swallow and may initiate epiglottal flipping to protect the airway. Most research on the role of the palatopharyngeal arch in swallowing has used pharyngeal manometry, which measures the relative pressures in the oropharynx, but does not quantify the movements of the structures involved in swallowing. In this study, we assessed palatopharyngeal arch and soft palate function by comparing their movements in a healthy population to a pathophysiological population longitudinally through infancy (term versus preterm pigs). In doing so, we test the impact of birth status, postnatal maturation and their interaction on swallowing. We tracked the three-dimensional movements of radiopaque beads implanted into relevant anatomical structures and recorded feeding via biplanar high-speed videofluoroscopy. We then calculated the total three-dimensional excursion of the arch and soft palate, the orientation of arch movement, and the timing of maximal arch constriction during each swallow. Soft palate excursion was greater in term infants at both seven and 17 days postnatal, whereas arch excursion was largely unaffected by birth status. Maximal arch constriction occurred much earlier in preterm pigs relative to term pigs, a result that was consistent across age. There was no effect of postnatal age on arch or soft palate excursion. Preterm and term infants differed in their orientation of arch movement, which most likely reflects both differences in anatomy and differences in feeding posture. Our results suggest that the timing and coordination of oropharyngeal movements may be more important to feeding performance than the movements of isolated structures, and that differences in the neural control of swallowing and its maturation in preterm and term infants may explain preterm swallowing deficits.

The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy

“…(a) The role of variation in muscle firing during feeding Younger pigs had higher variation in both muscle firing patterns and length changes relative to older pigs. Many of the behaviours associated with infant sucking and swallowing undergo postnatal maturation [12,38,39]. Our results indicate that the neural control of those behaviours may become less variable with age.…”

Head posture impacts mammalian hyoid position and suprahyoid muscle length: implication for swallowing biomechanics

“…Head-neck or head-trunk interactions are often necessary for successful food transport in vertebrates [25][26][27][28]. Human dysphagia patients are sometimes encouraged to adopt a specific head posture during swallowing [29,30], yet swallowing head posture has not been systematically documented across mammals in general [31]. In theory, individuals may adopt certain swallowing head postures for several, non-mutually exclusive reasons, including priming hyolingual muscle geometry for optimal control of hyoid position [24], and/or manipulating spatial dimensions of the pharynx for safer bolus transit [29,[32][33][34].…”

Effect of cue-based feeding on time to nipple feed and time to discharge in very low birth weight infants

“…The suck–swallow–breath pattern is not fully developed in an infant until around 32–34 weeks post-menstrual age (PMA) 2 . While seemingly simple for a healthy individual, this coordinated action can be difficult for preterm infants, due to differences in anatomy and neural physiology 3 – 5 . Attempts to nipple feed when not fully developed can lead to fatigue, risk of aspiration, and bradycardia during feeding 6 , 7 .…”