Differences in the swallowing process of newborns and healthy preterm infants: first results with a non-invasive bioimpedance and electromyography measurement system.

ABSTRACT

PURPOSE: Preterm infants (PI) have difficulty coordinating sucking, swallowing and breathing, and there is a risk of aspiration. The causes of this are not yet sufficiently understood. The aim of this study was to test a novel measurement device to measure breathing and pharyngeal processes involved in swallowing externally in everyday life to identify possible differences in neonates (NB) and PI. METHODS: Forty healthy NB were studied at 4-8 weeks of age (mean 6.7 weeks) and 20 healthy PI (mean gestational age 30.5 weeks) at postmenstrual age (PMA) 34/35 weeks (mean PMA 35.1 weeks) during a single feeding. Surface electrodes were used to measure bioimpedance and electromyography reflecting swallow-related changes in the pharynx and muscle activation of the tongue and submental muscles. A respiratory belt was combined with recording of the depth of chest movements and the occurrence of pauses in breathing. RESULTS: Velocity and extent of pharyngeal closure did not differ significantly across the feeding period (velocity p=0.09, closure p=0.17), but during the first two suck-swallow bursts PI had greater velocity (p<0.001*) and extent of pharyngeal closure (p=0.004*) than NB. The duration of swallowing phases was significantly longer in PIs (p<0.001*), their muscle activation decreased faster (p<0.001*), and they had more pauses in breathing than NBs. CONCLUSIONS: The novel measurement device allowed, for the first time in everyday life, the measurement of factors influencing swallowing and breath-swallow coordination in NBs and PIs. PIs showed differences from NBs most likely due to differences in muscle strength and condition.