Electromyography of muscles involved in feeding premature infants.

PURPOSE: To measure and compare the electrical activity of masseter, temporal, and suprahyoid muscles in premature newborn infants during breast-feeding and cup-feeding.

METHODS

This cross-sectional observational study was carried out by the electromyographic assessment of 36 preterm infants, 53% of whom were male, with mean gestational age of 32 weeks and birth weight of 1,719 g, fed via oral route, by full breast-feeding and supplementation of diet, through cup with expressed breast milk, until 15 days after hospital discharge. Children with neurological disorders, genetic syndromes, oral-motor, and/or congenital malformations were excluded. The different methods of feeding and the variables gestational age at birth, corrected gestational age, chronological age, birth weight and size, head circumference, and Apgar scores at 1 and 5 minutes were analyzed and compared by appropriate statistical analysis.

RESULTS

No difference was observed between breast-feeding and cup-feeding in the analysis of the temporal and masseter muscles. However, higher activity of suprahyoid musculature was observed during cup-feeding (p=0.001). The other variables were not correlated with the electrical activity of the muscles during the different feeding methods.

CONCLUSION

There may be a balance between the activity of the temporal and masseter muscles during breast-feeding and cup-feeding. There was higher activity of suprahyoid musculature during cup-feeding. This can be explained by the greater range of tongue movement, as premature infants usually perform tongue protrusion to get the milk from the cup.