Neonates' heart rate,sucking rhythm,and sucking amplitude as a function of the sweet taste

In previous studies of human newborn sucking, the effects of increasing fluid sweetness and/or volume included a decrease in sucking rate within sucking bursts and, paradoxically, an increase in heart rate. To determine whether the heart rate increase can be attributed to increased sucking amplitude for sweeter fluids, sucking and heart rates of 20 full-term infants were studied. Half sucked for three consecutive 2-min periods, first receiving small drops of water for each suck, then no fluid, then 15% sucrose. The other half experienced the reverse order. The results for sucking and heart rate were consistent with previous studies; sucking rates within bursts were slowest for sucrose and fastest for no fluid. Heart rate was higher for sucrose than for the other fluid conditions, however, only in the water-first group. The heart rate increase was significant on statistical tests which controlled for sucking amplitude as well as for several other motor variables. Sucking amplitude itself varied with fluid sweetness in the water-first group only, in which it was highest for water. There were more total sucks, longer sucking bursts, and less time between successive bursts under the sucrose condition. Multivariate statistics helped establish a set of dependent variables—sucking rate within bursts, total number of sucks, and heart rate—which most parsimoniously describes the effects of fluid sweetness. A hedonic explanation of the response of newborns to sweetness is thus reiterated.     

Effects of fluid delivery on the sucking response of the human newborn

Two experiments were conducted with human newborns to compare sucking behavior under nutritive and nonnutritive sucking conditions using several fixed-ratio schedules of reinforcement. Results showed that: (1) nutritive sucking produces higher over-all sucking rates but lower within-burst rates, (2) burst lengths are longer during nutritive than nonnutritive sucking, (3) fewer bursts per unit time occur during nutritive sucking, (4) fluid termination following nutritive sucking produces a sharp response decrement, suggestive of a negative contrast effect when compared with sucking rates under continuous no-fluid sucking. Response diminution occurs in the first 2–3 min of sucking under all conditions, reflecting the necessity of control comparisons in studies documenting sucking change under changing stimulus or reinforcement conditions.     

Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

The quality of sucking in infants with colic

Feeding problems have been reported in infants with colic. The purpose of this study was to examine the nutritive sucking pattern of infants identified as having colic. Twenty-nine infants (16 with colic and 13 controls) between the ages of 1 to 3 months, being bottle-fed by their mothers, were observed by a blind examiner. We hypothesized that infants with colic would show greater disorganization in nutritive sucking and show greater variability in sucking rate than infants without colic, as assessed by the revised Neonatal Oral Motor Assessment Scale (NOMAS). Infants with colic were found to present a disorganized sucking pattern; namely, a lack of rhythmical movement and a difference in amount of sucks per burst than infants without colic. Methods of intervention are suggested.     

Effects of nutritive and non-nutritive sucking on infant heart rate variability during the first 6 months of life

The effects of eating on heart rate variability (HRV) differ between adults and newborns. This may reflect the impact of suckling on the overall psychophysiological and autonomic nervous system maturation. The purpose of the present study was to explore whether the reactions of HRV during feeding change towards the adult pattern during the first 6 months of life. In addition, the effects of non-nutritive and nutritive sucking on heart rate (HR) and HRV were compared. The participants were 23 infants on whom recordings were performed as newborns and at 6, 12 and 24 weeks old. Nutritive sucking caused an increase in HR and a decline in HRV. The results were consistent with previous reports of a decrease in high frequency components of HRV during feeding in newborns, reflecting a decrease in parasympathetic activity. This response was apparent in all four ages studied, and remained similar throughout the 6-month period. However, age as an independent factor seemed to influence both HR and HRV. Pacifier sucking had no significant effects on HRV at any age. The results demonstrate the physical strain that sucking imposes on the baby, with a specific autonomic nervous system response involved. We consider this response an essential part of the overall psychophysiological maturation of infants.     

Effects of auditory stimulation upon non-nutritive sucking by premature infants.

Changes in non-nutritive sucking contingent upon presentation of an auditory stimulus previously found capable of eliciting heart-rate acceleration was investigated in a sample of 24 premature infants. Across 30 10-sec. presentations of the stimulus, only transient changes in sucking rate during the first 6 trials were observed, and these effects obtained primarily for those infants showing few abnormalities in their non-nutritive sucking behavior. These results were discussed as reflecting possible differences in infants' attention associated with sucking pathology and the dependence of psychological assessment upon the specific response index used.     

Analysis and treatment of finger sucking

We analyzed and treated the finger sucking of 2 developmentally typical children aged 7 and 10 years. The functional analysis revealed that the finger sucking of both children was exhibited primarily during alone conditions, suggesting that the behavior was maintained by automatic reinforcement. An extended analysis provided support for this hypothesis and demonstrated that attenuation of stimulation produced by the finger sucking resulted in behavior reductions for both children. Treatment consisted of having each child wear a glove on the relevant hand during periods when he or she was alone. Use of the glove produced zero levels of finger sucking for 1 participant, whereas only moderate reductions were obtained for the other. Subsequently, an awareness enhancement device was used that produced an immediate reduction in finger sucking.     

Dynamics of oralrespiratory coordination in full-term and preterm infants: II. Continuing effects at 3 months post term

Thirty-two infants participating in a longitudinal study of the effects of premature birth on sucking and breathing were tested at 3 months post term. They were assigned at a previous test to either a healthy full-term, healthy preterm, or high risk preterm group on the basis of birth weight, postconceptional age at birth, and perinatal medical status. Positive and negative sucking pressure as well as chest and abdominal breathing movements were recorded during nutritive sucking. The high risk preterms used a simpler and more stable pattern of coordination between sucking and breathing, were more likely to interrupt breathing at milk onset, and produced longer phase lags between positive and negative sucking pressure.     

Influence of auditory tempo on the endogenous rhythm of non-nutritive sucking

The aim of this study was to examine the perception of time in the first months of life. Does the perception of contextual temporal information (an auditory tempo) induce modifications in spontaneous motor behavior (in the present case, non-nutritive sucking behavior) at birth and at 2 months? Two auditory tempos were successively tested. The first was the same as the previously recorded spontaneous motor tempo (SMT); the second was 15% faster or 15% slower than the infant's SMT according to the group. Results showed that modification of the sucking tempo depended on age and contextual temporal information. Two-month-old infants were able to adapt their endogenous sucking rhythm to an external tempo if it was faster than their spontaneous rhythm. Results also confirmed that slowing down the sucking rate was difficult for both groups of infants. In sum, the results suggest that, to a certain extent, very young infants are sensitive to contextual modifications (which indicates that they perceive them). This study has thus identified certain features of the internal time base rate from birth which could help define a developmental internal clock model of contextual temporal processing.     

The organization of non-nutritive sucking in the premature infant

Changes in non-nutritive sucking contingent upon the repeated presentation of unpatterned and patterned light stimulation were examined in a sample of 18 premature infants. Stimulus contingent sucking change in chronologically younger infants tended to be somewhat shorter in duration than that of the chronologically older infants and showed stimulus contingent sucking acceleration as well as suppression. Evidence was also found for less orienting among infants showing abnormalities in their sucking behavior. No evidence for habituation was found in any subgroup. Possible factors contributing to the strength and nature of stimulus contingent non-nutritive sucking changes in infants are discussed.     

Effects of nonnutritive sucking on state and activity: Term-preterm comparisons

The effects of ad libitum access to a pacifier on the behavioral state and motor activity of preterm infants have been compared with those observed in full-term neonates. Regardless of maturity, nonnutritive sucking (NNS) decreases the amount of time spent in active states and increases that spent in quiescent states, lengthens the longest state bout, and decreases the frequency of state transitions. NNS also reduces overall motor activity as well as that during Active Sleep. Provided such ad libitum sucking opportunity, preterm infants thus appear to derive no less benefit from NNS than do term neonates. This result contrasts with an earlier finding that preterms are less soothed by NNA than are term infants.     

Depressed mothers' newborns show less discrimination of other newborns' cry sounds

Newborns' crying in response to the cry of another newborn has been called an empathetic response. The purpose of this study was to determine whether newborns of depressed mothers showed the same response. Newborns of depressed and non-depressed mothers were presented with cry sounds of themselves or other infants, and their sucking and heart rate were recorded. The newborns of non-depressed mothers responded to the cry sounds of other infants with reduced sucking and decreased heart rate. In contrast, the newborns of depressed mothers did not show a change in their sucking or heart rate to the cry sounds of other infants. This lesser attentiveness/responsiveness to other infants' cry sounds may predict their later lack of empathy.     

Evaluation of an awareness enhancement device for the treatment of thumb sucking in children

An evaluation of the awareness enhancement device (AED) described by Rapp, Miltenberger, and Long (1998) was conducted with 2 children who engaged in thumb sucking past the age at which it was developmentally appropriate. The AED effectively suppressed thumb sucking for both children. Future research evaluating the AED is discussed.     

Preference for infant-directed speech in preterm infants

The current study explores the effects of exposure to maternal voice on infant sucking in preterm infants. Twenty-four preterm infants averaging 35 weeks gestational age were divided randomly into two groups. A contingency between high-amplitude sucking and presentation of maternal voice was instituted for one group while the other group served as a yoked control. No significant differences were observed in sucking of the two groups, but the degree of pitch modulation of the maternal voice predicted an increase in the rate of infant sucking.     

"Transitional objects" as establishing operations for thumb sucking: a case study

This study examines the effects of a "transitional object" (surgical cloth) on the thumb sucking of a 3-year-old boy in two conditions: while sitting in the lap of his physical therapist and while alone in his crib. Sucking occurred when the cloth was present and did not occur when it was absent, regardless of condition. These results are discussed in terms of establishing operations, object attachment, and application.     

Differential sucking by neonates of depressed versus non-depressed mothers

Forty-two neonates (M = 39-h old) of depressed and non-depressed mothers sucked on cold (50 °F) and warm (78 °F) nipples on alternating trials. Half the infants received the cold nipple on the first of the eight trials (20 s each) and the other half received the warm nipple first. Neonates of depressed mothers sucked twice as much as neonates of non-depressed mothers, suggesting arousal dysregulation, overactivity or greater hedonic behavior in the newborns of depressed mothers. Although the newborns did not show a preference for cold or warm nipples, a temperature order effect revealed that neonates who received the cold nipple on the first trial sucked significantly more on trials 2–8 than those who received the warm nipple on the first trial, suggesting that an initially cold nipple might elicit greater sucking. More research is needed on maternal mood effects and temperature of objects to determine how these factors affect neonatal sucking behaviors.     

Discrimination of color and pattern novelty in one-month human infants

Visual discrimination of novel colors and patterns by one-month infants was studied in two experiments where visual reinforcers were presented contingent upon infants' rate of nonnutritive, high-amplitude sucking. Discrimination was measured by recovery of sucking to the presentation of novel visual reinforcing stimuli following decrements in sucking to familiar visual stimuli. In Expt 1, following decrement to familiar stimuli, independent groups received either a change in color, pattern, both color and pattern, or no stimulus change. Reliable recovery was demonstrated for the three stimulus novelty groups relative to the no-change control. Experiment 2, employing achromatic visual reinforcers also showed reliable recovery to pattern change relative to no-change controls. These findings with one-month infants indicate discrimination between familiar and novel visual reinforcers on the basis of color and pattern differences and an increase due to novelty in the reinforcing effectiveness of visual stimuli. Individual subject differences in response decrement magnitude during familiarization were positively correlated with amount of response recovery to novelty.     

Microcomputer measurement and analysis of newborn sucking

An on-line Basic computer program with on-line monitor prompts and read-out collects, stores, and digitizes pressure and latency of sucking responses for later analyses. The program and analog equipment are described, and approximate costs are noted.     

Comparison of tongue muscle characteristics of preterm and full term infants during nutritive and nonnutritive sucking

Background

Independent oral feeding requires coordination of suck, swallow and breathe and the lingual musculature plays a significant role in this coordinative action. However, clinical benchmarks of lingual function fundamental to successful feeding have not been explored.

Aims

The present study tests our model for quantifying infant lingual force and size and compares the muscle measures of interest in two cohorts: healthy full-term infants (FT) (N = 5) and healthy preterm infants (PT) (N = 6).

Method

Using an instrumented pacifier and bottle nipple, we determined the resultant compressive forces applied to the nipple by the tongue during nutritive (NS) and nonnutritive sucking (NNS). Muscle size was estimated from measures of posterior tongue thickness using ultrasonography.

Results

After controlling for weight and post menstrual age, statistically significant differences were found between FT and PT infants beginning to feed for NNS frequency and NS tongue force. Clinically significant differences were detected for NNS tongue force and posterior tongue thickness. Additionally, PT infants demonstrated a significant difference in mean tongue force between NS and NNS and FT infants did not. FT infants demonstrated a significant difference in mean frequency between NS and NNS and PT infants did not. Linear regression indicated that mean posterior tongue thickness alone predicted 55% of the variance in NS force.

Conclusions

Results demonstrate the feasibility of our approach and suggest that infant tongue muscle characteristics necessary for successful feeding differ between healthy full term infants and preterm infants who are beginning oral feeding.     

A further analysis of the effect of satiation on the sucking response in puppies

The Psychological Record - A total of 84 tests were made on puppies to further examine the influence of stomach injected food on the sucking reflex. Sucking followed injection of milk in every...