Synthetic orocutaneous stimulation entrains preterm infants with feeding difficulties to suck

Abstract

Background: Prematurity can disrupt the development of a specialized neural circuit known as suck central pattern generator (sCPG), which often leads to poor feeding skills. The extent to which suck can be entrained using a synthetically patterned orocutaneous input to promote its development in preterm infants who lack a functional suck is unknown.

Objective: To evaluate the effects of a new motorized 'pulsating' pacifier capable of entraining the sCPG in tube-fed premature infants who lack a functional suck and exhibit feeding disorders.

Methods: Prospective cohort study of 31 preterm infants assigned to either the oral patterned entrainment intervention (study) or non-treated (controls) group, matched by gestational age, birth weight, oxygen supplementation history and oral feed status. Study infants received a daily regimen of orocutaneous pulse trains through a pneumatically controlled silicone pacifier concurrent with gavage feeds.

Results: The patterned orocutaneous stimulus was highly effective in accelerating the development of non-nutritive suck (NNS) in preterm infants. A repeated-measure multivariate analysis of covariance revealed significant increases in minute rates for total oral compressions, NNS bursts, and NNS cycles, suck cycles per burst, and the ratiometric measure of NNS cycles as a percentage of total ororhythmic output. Moreover, study infants also manifest significantly greater success at achieving oral feeds, surpassing their control counterparts by a factor of 3.1 x (72.8% daily oral feed versus 23.3% daily oral feed, respectively).

Conclusion: Functional expression of the sCPG among preterm infants who lack an organized suck can be induced through the delivery of synthetically patterned orocutaneous pulse trains. The rapid emergence of NNS in treated infants is accompanied by a significant increase in the proportion of nutrient taken orally.

Figures

Figure 1

N Trainer system engineered in our laboratory to produce synthetic patterned oral somatosensory stimulation in preterm infants.

Figure 2

A sample of the digitally synthesized control signal (DAC – top panel), resultant pacifier intraluminal air pressure (middle panel), and radial displacement of the pacifier nipple during NTrain stimulation (bottom panel). The synthetic pulse train used to mimic NNS burst-pause structure consisted of a series of 6-cycle bursts and 2-second pause periods. Within-burst cycle rate was 1.8 Hz.

Figure 3

A sample response history for a preterm infant who began the NTrainer patterned orosensory treatment regimen at 35.4 weeks PMA without a functional suck and 0% oral feed. The upper panel shows the daily and cumulative history of NTrainer sessions administered to the infant. Periodic assessment of NNS dynamics using NeoSuck is given at two baseline Pre- Treatment points (A,B) in the lower left panels, and repeated at days 4 and 9 of the oral pattern stimulation regimen in the lower right waveform panels (C,D). The absence of an organized NNS pattern during the pre-treatment phase is replaced with the classic NNS burst-pause pattern and rapid progress toward oral feed competence.