Preterm infant swallowing of thin and nectar-thick liquids: changes in lingual-palatal coordination and relation to bolus transit.

Tongue-soft palate coordination and bolus head pharyngeal transit were studied by means of postacquisition kinematic analysis of videofluoroscopic swallowing images of ten preterm infants referred from hospital NICUs due to poor oral feeding and suspicion of aspiration. Sequences of coordinated tongue-soft palate movements and bolus transits during swallows of thin-consistency and nectar-thick-consistency barium were digitized, and time series data were used to calculate continuous relative phase, a measure of coordination. During swallows of nectar-thick compared to thin barium, tongue-soft palate coordination was more likely to be antiphase, bolus head pharyngeal transit time was longer, and coordination was significantly correlated with bolus head pharyngeal transit. Analysis of successive swallows indicated that tongue-soft palate coordination variability decreased with nectar-thick but not with thin-consistency barium. Together, the results suggest that slower-moving bolus transits may promote greater opportunity for available sensory information to be used to modulate timing of tongue-soft palate movements so that they are more effective for pumping liquids.