Developmental patterns of rhythmic suck and swallow in preterm infants

Abstract

Twenty healthy preterm infants (gestational age 26 to 33 weeks, postmenstrual age [PMA] 32.1 to 39.6 weeks, postnatal age [PNA] 2.0 to 11.6 weeks) were studied weekly from initiation of bottle feeding until discharge, with simultaneous digital recordings of pharyngeal and nipple (teat) pressure and nasal thermistor and thoracic strain gauge readings. The percentage of sucks aggregated into 'runs' (defined as > or = 3 sucks with < or = 2 seconds between suck peaks) increased over time and correlated significantly with PMA (r=0.601, p<0.001). The length of the sucking-runs also correlated significantly with PMA (r=0.613, p<0.001). The stability of sucking rhythm, defined as a function of the mean/SD of the suck interval, was also directly correlated with increasing PMA (r=0.503, p=0.002), as was increasing suck rate (r=0.379, p<0.03). None of these measures was correlated with PNA. Similarly, increasing PMA, but not PNA, correlated with a higher percentage of swallows in runs (r=0.364, p<0.03). Stability of swallow rhythm did not change significantly from 32 to 40 weeks' PMA. In low-risk preterm infants, increasing PMA is correlated with a faster and more stable sucking rhythm and with increasing organization into longer suck and swallow runs. Stable swallow rhythm appears to be established earlier than suck rhythm. The fact that PMA is a better predictor than PNA of these patterns lends support to the concept that these patterns are innate rather than learned behaviors. Quantitative assessment of the stability of suck and swallow rhythms in preterm infants may allow prediction of subsequent feeding dysfunction as well as more general underlying neurological impairment. Knowledge of the normal ontogeny of the rhythms of suck and swallow may also enable us to differentiate immature (but normal) feeding patterns in preterm infants from dysmature (abnormal) patterns, allowing more appropriate intervention measures.

Cue-based oral feeding clinical pathway results in earlier attainment of full oral feeding in premature infants

“…While there has been discussion regarding whether the maturation of suck-swallow-breathe coordination is related to the infant's PMA or experience, Simpson et al 5 recently found that experience may play the more important role. 18,19 While there was a trend toward starting oral feedings earlier in our study, the difference was not statistically significant. Because this study included the first patients put on the clinical pathway, relative inexperience in assessing signs of feeding readiness may have kept some staff from starting oral feedings at an earlier PMA.…”

Sucking and swallowing in infants and diagnostic tools

“…This stabilization correlates more with PMA than with postnatal age. 20 The studies by Gewolb et al 20 show that rhythm is an integrated part of maturation. Quereshi et al 16 expand on this theme by explaining that the changes observed at 1 month of age may be an adaptation of the drinking pattern to include volition, with longer sequences and a larger number of sucking movements.…”

“…From this point of view, it is likely that these behavioral patterns are congenital rather than acquired. 20 However, the rhythmicity of the suck-swallow-breath relationship depends also on nonmaturational factors, such as satiety, behavioral state and milk flow. Milk flow depends on the hole size of the nipple (bottle feeding), the milk ejection reflex (in breastfeeding), but it also depends on the infant.…”

“…Within certain ranges the infant can autoregulate milk flow by changing the suction pressure and frequency. 17,21 Rhythmic stability can be expressed in a measure used by Gewolb et al, 20,22 the coefficient of variation. The coefficient of variation is the standard deviation of the intervals between two processes (such as swallow-swallow, suck-suck, suck-swallow) divided by the mean interval between these processes.…”

The development of potentially better practices to support the neurodevelopment of infants in the NICU

“…155 At about 32 weeks gestation, an infant will begin to display bursts of sucking, and by 34 weeks a rhythmic suck, swallow and breathe pattern is developing. [156][157][158][159][160][161] Non-nutritive sucking will transition towards more effective nutritive sucking, concurrent with state of alertness and increasing gestational age. 162 Non-nutritive sucking with pacifier use may facilitate the transition to effective nutritive sucking at 32 to 34 weeks gestation.…”