Neonatal sucking behavior: Comparison of perioral movement during breast-feeding and bottle feeding

Background:  The aim of the present study was to compare orofacial motion and mouth angle during breast-feeding and bottle feeding in normal infants.
Methods:  Thirteen normal infants were enrolled in the study, and feeding sessions were recorded using a digital video camera at 4 or 5 days following birth. The analysis was successfully performed for 12 infants during both breast-feeding and bottle feeding. Markers were placed at the lateral angle of the eye, the tip of the jaw, and the throat region. Jaw and throat region movements were calculated using the direct linear transformation method. The angle of the mouth was also measured.
Results:  Throat region movement was significantly larger than jaw movement in both breast-feeding (eye–throat region changes: 1.51 ± 0.37 mm, eye–jaw changes: 0.91 ± 0.31 mm, P < 0.001) and bottle feeding (eye–throat region changes: 2.91 ± 0.46 mm, eye–jaw changes: 1.77 ± 0.33 mm, P < 0.001). Jaw and throat region movements were significantly smaller during breast-feeding than those during bottle feeding ( P < 0.001). The angle of the mouth during breast-feeding is larger than that during bottle feeding ( P < 0.001). There was a negative correlation between the angle of the mouth and jaw movement.
Conclusions:  Jaw and throat region movements during bottle feeding differ from those during breast-feeding. This partly results from the difference in the angle of the mouth during feeding.     

Feeding behaviour of infants with cleft lip and palate

AIM: To determine whether the feeding behaviour of infants with cleft lip and palate is improved with a type-P teat, which is widely used in Japan by such infants, compared with a standard teat. The difference in intra-oral movements between the type-P teat, modified for the evaluation of feeding behaviour, and an unmodified type-P teat was also compared using ultrasonography. METHODS: In part 1 of the study, 15 infants aged 2 to 3 mo and 7 infants aged 2 wk were evaluated for sucking pressure, expression pressure, frequency and duration of sucking. All the infants had a complete unilateral cleft lip and palate without any other abnormalities. In part 2, an ultrasonographic analysis of intra-oral movement was done for 5 infants enrolled in part 1 of the study. RESULTS: Sucking pressure did not occur in all infants. It was found that feeding efficiency improved with the type-P teat compared with the standard teat. The expression pressure with the type-P teat was significantly higher than that with the standard teat, and the feeding frequency with the type-P teat was lower than that with the standard teat. CONCLUSION: A type-P teat is suitable for infants with cleft lip and palate who have sucking difficulties. However, a type-P nipple with a squeezable bottle does not fully solve the feeding problems of infants with cleft lip and palate. New artificial teats that allow a higher expression pressure are desirable, and the measurement of the expression pressure may be helpful in the evaluation of artificial nipples.     

A Pilot Study of Oral-Motor Dysfunction in “At-Risk” Infants

The purposes of this pilot study were to devise a neonatal oral-motor assessment scale (NOMAS), and to correlate oral-motor function with feeding histories, perinatal-neonatal complications, neurologic status, and polygraphic recording of sucking. The methods used to study the at-risk infants were polygraphic amplification and recording of intra-oral pressure waves; scoring of sucking behavior with the NOMAS occurred concurrently with instrumental measurement. Both non-nutritive (NNS) and nutritive sucking (NS) modes were tested. Oral-motor performance tended to be disorganized or dysfunctional in infants with intraventricular hemorrhage (IVH) and asphyxia neonatorum. Those infants with brain insults (IVH, hydrancephaly) showed slower sucking rates in NNS, and the degree of slowing of the rate when switched to NS was less in these higher-risk infants. The polygraphic data did not, however, distinguish those same infants who had abnormal NOMAS scores. Oral-motor dysfunction was identified only from 40 weeks corrected age (C.A.) and correlated with generalized hypotonia on neurological examination. Polygraphic data further substantiated that oral-motor dysfunction may be the result of deviant jaw movement. Deviant motor patterns observed between 35 and 37 weeks C.A. were not easily identifiable as oral-motor dysfunction and probably represented incoordination or disorganization because, although differences in oral-motor function were noted, normal movements of both the tongue and jaw were present. Further study is needed to determine if oral-motor disorganization noted between 35 and 37 weeks can be attributed to immaturity or whether oral-motor function deteriorates with loss of normal movement, so that by term age dysfunction is subsequently noted.     

Characterization of the developmental stages of sucking in preterm infants during bottle feeding

It is acknowledged that the difficulty many preterm infants have in feeding orally results from their immature sucking skills. However, little is known regarding the development of sucking in these infants. The aim of this study was to demonstrate that the bottle-feeding performance of preterm infants is positively correlated with the developmental stage of their sucking. Infants' oral-motor skills were followed longitudinally using a special nipple/bottle system which monitored the suction and expression/compression component of sucking. The maturational process was rated into five primary stages based on the presence/absence of suction and the rhythmicity of the two components of sucking, suction and expression/compression. This five-point scale was used to characterize the developmental stage of sucking of each infant. Outcomes of feeding performance consisted of overall transfer (percent total volume transfered/volume to be taken) and rate of transfer (ml/min). Assessments were conducted when infants were taking 1-2, 3-5 and 6-8 oral feedings per day. Significant positive correlations were observed between the five stages of sucking and postmenstrual age, the defined feeding outcomes, and the number of daily oral feedings. Overall transfer and rate of transfer were enhanced when infants reached the more mature stages of sucking. We have demonstrated that oral feeding performance improves as infants' sucking skills mature. In addition, we propose that the present five-point sucking scale may be used to assess the developmental stages of sucking of preterm infants. Such knowledge would facilitate the management of oral feeding in these infants.     

The analysis of sucking behaviour in newborn infants.

A special video camera devised by the author and a fiberscope were used to film the neonatal sucking response of 50 low-risk full-term newborn infants on the 5th day after birth. Analysis of the sucking behaviour showed that the sucking movements consist mainly of a peristaltic tongue movement and two kinds of negative pressure; that the peristaltic tongue movements are synchronized with the jaw movements; that infants actively adapt to a varying environment; and that the sucking movements change to minimize the energy required.     

Antenatal olfactory learning influences infant feeding

The aim is to know whether antenatal olfactory learning have a greater effect than postnatal olfactory learning on infant feeding even in the absence of triggering signals. We evaluated the sucking behavior of infants completely separated from their mothers for 10-14 days since birth. The 12 infants admitted to Chiba Children's Hospital were studied at 10-14 days of age. Oral feeding was initiated at 4-7 days of age. The sucking and expression pressures, frequency, and sucking efficiency were measured during bottle-feeding with exposure to odors of mother's milk, formula, and water. The mother's milk odor elicited more frequent sucking with higher expression pressure than did formula or water. In conclusion, the odor preferences acquired independently from postnatal experience may have a greater effect than postnatal olfactory learning on sucking activity.     

Coordination of suck-swallow and swallow respiration in preterm infants

Safe oral feeding of infants necessitates the coordination of suck-swallow-breathe. Healthy full-term infants demonstrate such skills at birth. But, preterm infants are known to have difficulty in the transition from tube to oral feeding. AIM: To examine the relationship between suck and swallow and between swallow and breathe. It is hypothesized that greater milk transfer results from an increase in bolus size and/or swallowing frequency, and an improved swallow-breathe interaction. METHODS: Twelve healthy preterm (<30 wk of gestation) and 8 full-term infants were recruited. Sucking (suction and expression), swallowing, and respiration were recorded simultaneously when the preterm infants began oral feeding (i.e. taking 1-2 oral feedings/d) and at 6-8 oral feedings/d. The full-term infants were similarly monitored during their first and 2nd to 4th weeks. Rate of milk transfer (ml/min) was used as an index of oral feeding performance. Sucking and swallowing frequencies (#/min), average bolus size (ml), and suction amplitude (mmHg) were measured. RESULTS: The rate of milk transfer in the preterm infants increased over time and was correlated with average bolus size and swallowing frequency. Average bolus size was not correlated with swallowing frequency. Bolus size was correlated with suction amplitude, whereas the frequency of swallowing was correlated with sucking frequency. Preterm infants swallowed preferentially at different phases of respiration than those of their full-term counterparts. CONCLUSION: As feeding performance improved, sucking and swallowing frequency, bolus size, and suction amplitude increased. It is speculated that feeding difficulties in preterm infants are more likely to result from inappropriate swallow-respiration interfacing than suck-swallow interaction.     

Development of sucking behavior in infants who have not been fed for 2 months after birth

BACKGROUND: Term infants are able to develop sucking behavior after birth. However, the requirements for this development have not yet been fully elucidated. In the present study, we investigated whether an oral-feed practice is necessary for the development of sucking behavior and whether non-nutritive sucking could support the development of this behavior while the infants cannot be fed. METHODS: Subjects of the present study were four term or near-term infants who had never been fed orally for approximately 2 months after birth because of gastrointestinal problems. Sucking pressure was measured with a silicone tube inserted into an artificial nipple and sucking efficiency was calculated during an entire feeding. RESULTS: Sucking pressure, frequency and duration at the first time oral feed corresponded to values obtained for normal-term infants at their first oral feed. Although infants who had not received oral feeding demonstrated poor sucking abilities initially, sucking performance improved with practice. Sucking parameters measured 1 month since oral feeding was initiated in these infants corresponded to values obtained for normal-term infants at 1 month of age. Although infants who had not received oral feeding had often sucked a pacifier for sedation, this non-nutritive sucking did not result in the development of sucking behavior. CONCLUSIONS: These results demonstrate that an oral feeding practice is necessary for the development of sucking behavior and that non-nutritive sucking does not affect the development of sucking.     

Does the choice of bottle nipple affect the oral feeding performance of very‐low‐birthweight (VLBW) infants?

Background: There is a continuous debate regarding the best bottle nipple to be used to enhance the bottle-feeding performance of a preterm infant. Aim: To verify that feeding performance can be improved by using the bottle nipple with the physical characteristics that enhance infants' sucking skills. Methods: Ten “healthy” VLBW infants (941±273 g) were recruited. Feeding performance was monitored at two time periods, when taking 1-2 and 6-8 oral feedings/d. At each time and within 24 h, performance was monitored using three different bottle nipples offered in a randomized order. Rate of milk transfer (ml/min) was the primary outcome measure. The sucking skills monitored comprised stage of sucking, suction amplitude, and duration of the generated negative intraoral suction pressure. Results: At both times, infants demonstrated a similar rate of milk transfer among all three nipples. However, the stage of sucking, suction amplitude, and duration of the generated suction were significantly different between nipples at 1-2, but not 6-8 oral feedings/d.

Conclusion: We did not identify a particular bottle nipple that enhanced bottle feeding in healthy VLBW infants. Based on the notion that afferent sensory feedback may allow infants to adapt to changing conditions, we speculate that infants can modify their sucking skills in order to maintain a rate of milk transfer that is appropriate with the level of suck-swallow-breathe coordination achieved at a particular time. Therefore, it is proposed that caretakers should be more concerned over monitoring the coordination of suck-swallow-breathe than over the selection of bottle nipples.     

Maturation of oral feeding skills in preterm infants

AIM: Safe and successful oral feeding requires proper maturation of sucking, swallowing and respiration. We hypothesized that oral feeding difficulties result from different temporal development of the musculatures implicated in these functions. METHODS: Sixteen medically stable preterm infants (26 to 29 weeks gestation, GA) were recruited. Specific feeding skills were monitored as indirect markers for the maturational process of oral feeding musculatures: rate of milk intake (mL/min); percent milk leakage (lip seal); sucking stage, rate (#/s) and suction/expression ratio; suction amplitude (mmHg), rate and slope (mmHg/s); sucking/swallowing ratio; percent occurrence of swallows at specific phases of respiration. Coefficients of variation (COV) were used as indices of functional stability. Infants, born at 26/27- and 28/29-week GA, were at similar postmenstrual ages (PMA) when taking 1-2 and 6-8 oral feedings per day. RESULTS: Over time, feeding efficiency and several skills improved, some decreased and others remained unchanged. Differences in COVs between the two GA groups demonstrated that, despite similar oral feeding outcomes, maturation levels of certain skills differed. CONCLUSIONS: Components of sucking, swallowing, respiration and their coordinated activity matured at different times and rates. Differences in functional stability of particular outcomes confirm that maturation levels depend on infants' gestational rather than PMA.     

Prediction for developmental delay on Neonatal Oral Motor Assessment Scale in preterm infants without brain lesion

Background:  Preterm infants often have difficulty in achieving a coordinated sucking pattern. To analyze the correlation between preterm infants with disorganized sucking and future development, weekly studies were performed of 27 preterm infants from initiation of bottle feeding until a normal sucking pattern was recognized.
Methods:  A total of 27 preterm infants without brain lesion participated in the present study. Neonatal Oral Motor Assessment Scale (NOMAS) was utilized to evaluate the sucking pattern. Infants who were initially assessed as having disorganized sucking on NOMAS and regained a normal sucking pattern by 37 weeks old were assigned to group I; infants with a persistent disorganized sucking pattern after 37 weeks were assigned to group II. The mental (MDI) and psychomotor (PDI) developmental indices of Bayley Scales of Infant Development, second edition were used for follow-up tests to demonstrate neurodevelopment at 6 months and 12 months of corrected age.
Results:  At 6 months follow up, subjects in group I had a significantly higher PDI score than group II infants ( P = 0.04). At 12 months follow up, group I subjects had a significantly higher score on MDI ( P = 0.03) and PDI ( P = 0.04). There was also a higher rate for development delay in group II at 6 months ( P = 0.05).
Conclusion:  NOMAS-based assessment for neonatal feeding performance could be a helpful tool to predict neurodevelopmental outcome at 6 and 12 months. Close follow up and early intervention may be necessary for infants who present with a disorganized sucking pattern after 37 weeks post-conceptional age.     

Gastric Suction in Healthy Newborn Infants Effects on Circulation and Developing Feeding Behaviour

ABSTRACT. Gastric emptying of newborn infants is a procedure performed to prevent aspiration of gastric contents. The present investigation was conducted to study the effects of gastric suction on circulatory and behavioural parameters in 21 healthy newborn children (11 cases, 10 controls). A small elevation in mean arterial blood pressure was observed during gastric suction. The incidence of retching was also increased. In all children spontaneous sucking and rooting movements, as well as state of sleep and wakefulness were recorded. In the control group spontaneous sucking and rooting movements started to occur 15 min after birth and reached a maximum at 45 and 60 min, respectively. The first hand to mouth movement was observed after a mean of 34 min and the infants found the nipple and started to suckle at about 55 min. This sequence of prefeeding behaviour was disrupted in children who had undergone gastric suction. The physiological side-effects induced by gastric suction are minor, but it seemed to be unpleasant for the child and no clear advantages are gained by the procedure.     

Gastric suction in healthy newborn infants. Effects on circulation and developing feeding behaviour

Gastric emptying of newborn infants is a procedure performed to prevent aspiration of gastric contents. The present investigation was conducted to study the effects of gastric suction on circulatory and behavioural parameters in 21 healthy newborn children (11 cases, 10 controls). A small elevation in mean arterial blood pressure was observed during gastric suction. The incidence of retching was also increased. In all children spontaneous sucking and rooting movements, as well as state of sleep and wakefulness were recorded. In the control group spontaneous sucking and rooting movements started occur 15 min after birth and reached a maximum at 45 and 60 min, respectively. The first hand to mouth movement was observed after a mean of 34 min and the infants found the nipple and started to suckle at about 55 min. This sequence of prefeeding behaviour was disrupted in children who had undergone gastric suction. The physiological side-effects induced by gastric suction are minor, but it seemed to be unpleasant for the child and no clear advantages are gained by the procedure.     

Breathing pattern and ventilation during oral feeding in term newborn infants

The effect of oral feeding on breathing pattern and ventilation was studied in 19 healthy term neonates in the semiupright supine position. Ventilation was measured with a nasal flowmeter, and sucking pressure via a modified nipple that permitted milk delivery. The feeding pattern in these infants consisted of an initial period of continuous sucking followed by intermittent sucking for the remainder of the feed. A significant reduction in minute ventilation (P less than 0.01) was observed during continuous sucking, and resulted entirely from a reduction in breathing frequency (P less than 0.01). Tidal volume did not change (P greater than 0.05), but prolongation of expiration (P less than 0.01) and shortening of inspiration (P less than 0.05) were also observed. During intermittent sucking, the minute ventilation was similar to that of the control period. However, smaller but significant changes in breathing frequency and in duration of inspiration and expiration persisted during intermittent sucking. Our results document a significant reduction in ventilation during the initial part of oral feeding in term neonates, and subsequent recovery with continued feeding. Depending on the magnitude of this reduction in ventilation, cyanosis and bradycardia may develop in some infants during oral feeding.     

The maturation and coordination of sucking,swallowing, and respiration in preterm infants

OBJECTIVES: Our objectives were to establish normative maturational data for feeding behavior of preterm infants from 32 to 36 weeks of postconception and to evaluate how the relation between swallowing and respiration changes with maturation. STUDY DESIGN: Twenty-four infants (28 to 31 weeks of gestation at birth) without complications or defects were studied weekly between 32 and 36 weeks after conception. During bottle feeding with milk flowing only when infants were sucking, sucking efficiency, pressure, frequency, and duration were measured and the respiratory phase in which swallowing occurs was also analyzed. Statistical analysis was performed by repeated-measures analysis of variance with post hoc analysis. RESULTS: The sucking efficiency significantly increased between 34 and 36 weeks after conception and exceeded 7 mL/min at 35 weeks. There were significant increases in sucking pressure and frequency as well as in duration between 33 and 36 weeks. Although swallowing occurred mostly during pauses in respiration at 32 and 33 weeks, after 35 weeks swallowing usually occurred at the end of inspiration. CONCLUSIONS: Feeding behavior in premature infants matured significantly between 33 and 36 weeks after conception, and swallowing infrequently interrupted respiration during feeding after 35 weeks after conception.     

Decreased ventilation in preterm infants during oral feeding

As respiratory difficulty may accompany nipple feeding in preterm neonates, we studied the effect of oral feeding on ventilation in 23 preterm infants. The infants composed two groups based on their postconceptional age at the time of study: Group A comprised 12 infants 34 to 35.9 weeks of age, and group B, 11 infants 36 to 38 weeks. Ventilation was measured via a nasal mask pneumotachometer, and sucking pressure via a nipple that also permitted milk delivery; transcutaneous PO2 and PCO2 were continuously monitored. The feeding pattern comprised an initial period of continuous sucking of at least 30 seconds, followed by intermittent sucking bursts for the remainder of the feed. When compared with an initial semi-upright control period, minute ventilation (V1) during continuous sucking fell by 52 +/- 6% (P less than 0.001) and 40 +/- 2% (P less than 0.001) in groups A and B, respectively. This was the result of a decrease in respiratory frequency and tidal volume and was associated with a fall in TcPO2 of 13 +/- 4 mm Hg (P less than 0.01) in group A and 10 +/- 2 mm Hg (P less than 0.01) in group B. During intermittent sucking, V1 and TcPO2 recovered partially only in the more mature infants (group B). At the end of the feed, TcPCO2 have risen by 3 +/- 1 mm Hg (P less than 0.001) in group A and by 2 +/- 2 mm Hg (P less than 0.05) in group B. Thus oral feeding results in an impairment of ventilation during continuous sucking and the subsequent recovery during intermittent sucking is dependent on postconceptional age.     

The effects of body positioning on sucking behaviour in sick neonates

Some infants show better oxygenation in the prone position compared to the supine position while they are bottle-fed; however, the reason for this phenomenon is not clear. The purpose of this study was to obtain a better understanding of the effects of body position on the oral feeding performance, i.e. the sucking pressure, frequency, efficiency, and ventilation. A total of 14 infants (12 full-term, 2 preterm), who often showed O₂ desaturation (SpO₂ < 90) during oral feeding, were enrolled in the study. The infants were fed either in the supine position or in the prone position throughout feeding. Oxygen saturation was recorded with a pulse oxymeter. The sucking pressure was measured with a 1 mm I.D. silicone tube inserted into the artificial nipple. The ventilation volume during bottle feeding was measured with a pneumotachograph. The prone position resulted in better oxygenation (97.2 ± 0.6% prone, 92.5 ± 0.9% supine, P < 0.05) and larger tidal volume (6.4 ± 0.8 ml/kg prone and 4.9 ± 0.6 ml/kg supine, P < 0.05), although the minute ventilation during bottle-feeding was not different from that in the supine position. In the prone position, the sucking pressure and frequency were higher and the duration of each suck was shorter. Conclusion Sucking in the prone position may to some extent reduce disadvantages of oral feeding on ventilation. Received: 18 January 2000 / Accepted: 9 May 2000     

Effect of suckling on the peripheral sensitivity of full-term newborn infants

BACKGROUND: Sucking may reduce the manifestations of pain in newborn infants. OBJECTIVE: To examine the effect of suckling on the threshold for peripheral somatosensory responses. Subjects and methods: Graded Von Frey filaments were applied to the heel to initiate peripheral somatosensory responses (withdrawal reflex and gross body movements) in term infants. RESULTS: Dummy sucking increases the somatosensory threshold, but breast feeding had a more marked effect, increasing the threshold of the flexion withdrawal reflex (p相似文献   

Développement de l'oralité chez le nouveau-né prématuré

Preterm infants cannot readily transition from tube to oral feeding. Such difficulty often delays their discharge from the hospital and mother-infant reunion. Therefore, understanding the development of the necessary skills preterm infants need to acquire for safe and successful oral feeding is essential. It is now recognized that a mature sucking pattern consisting of the rhythmic alternation of suction and expression is not sufficient for an infant to feed by mouth safely. Rather, an adequate coordination of sucking, swallowing, and respiration appear to be crucial if the infant is to feed with no episodes of desaturation, apnea, bradycardia, and/or aspiration. Studies have shown the benefits of some interventions in facilitating oral feeding in the preterm infant. However, it remains to be determined whether these effects can be generalized.     

The relationship between birth weight and feeding maturation in preterm infants

Aim: To report changes in ingestive behaviour from 35 to 40 weeks post-conceptual age and examine the association between birth weight and feeding maturation in preterm infants.
Methods: One hundred and four preterm infants born 24 to 34 weeks gestational age were studied. Feeding maturation was assessed as the change from 35 to 40 weeks post-conceptual age in the number of sucks over 5 min, sucking bursts, sucks per burst, time between bursts and maximum pressure during a suck (Pmax). The association between birth weight and each sucking behaviour was examined after adjusting for potential confounders.
Results: Significant changes in feeding maturation occurred between 35 and 40 weeks. Birth weight was positively associated with change in Pmax and change in number of sucks per burst for extremely premature infants born 24 to <29 weeks gestational age but not for very premature infants born ≥29 to 34 weeks. The association between birth weight and change in Pmax for extremely premature infants remained significant after adjustment (adjusted beta = 0.128 mmHg increase in change in maximum sucking pressure per every 1 g of birth weight, 95% CI = 0.017, 0.239, p = 0.03).
Conclusion: Birth weight is positively associated with maturation in maximum sucking pressure among infants born extremely premature.