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.     

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.     

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 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.     

The effects of the environment upon state cycles in the human newborn

The effects of increased ambient noise level or decreased illumination level upon the postprandial state cycles of the neonate were investigated. As compared to the control group of subjects only the dimmer light condition had any effect. It was found to stabilize the respiration rate per minute over the subjects irrespective of state and to significantly lower the mean respiration rate in epochs of either Alertness or Active Sleep. The increased level of ambient noise had no such effect. Neither environmental change significantly affected the cycling of the states in the post-prandial period nor did they have any effect upon the mean heart rate per minute of the babies. A simple explanation for the positive effect of the dim-light condition was offered.     

Locus of habituation in the human newborn

There is some controversy concerning the youngest age at which an infant will habituate to a visual stimulus or will prefer a novel to a familiar pattern. One suggestion has been that apparently successful reports of habituation and dishabituation in the newborn baby are attributable to retinal adaptation. This interpretation was tested in two experiments. In both experiments monocular conditions of viewing were used: newborns were habituated with one eye as the 'seeing' eye, and posthabituation novelty preferences investigated with the other eye. Significant preferences were found both for a novel colour (experiment 1) and for a novel shape (experiment 2), which implies that a retinal-adaptation model can be ruled out. It is suggested that the habituation effects and the subsequent novelty preferences found in the experiments are most reasonably interpreted as a function of memory formation, and evidence is presented for the storage of visual experience from birth. The results also demonstrate some form of binocular interaction in the newborn.     

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.     

National evaluation of US newborn screening system components

Newborn screening has existed as a state-based public health service since the early 1960s. Every state and most territorial jurisdictions have comprehensive newborn screening programs in place, but in the United States a national newborn screening policy does not exist. This results in different administrative infrastructures, screening requirements, laboratory and follow-up services, medical management approaches, and related activities across the country. Federal initiatives and support have contributed to limited evaluations of various aspects of individual newborn screening programs at the national level, but funding is an issue. The national evaluation strategies have taken various forms, all with the intent of improving the screening system through review of actions taken and suggestions for future improvements. While participation in the national evaluation effort for newborn screening laboratory practices includes all US programs, and this has aided in improving quality and harmonizing protocols, other national evaluation activities have been only moderately successful. National data reporting of quality indicators for various program elements must be comprehensive and timely, and the elements must be universally accepted in order to meet the evaluation and improvement needs of the national newborn screening system. A comprehensive real time national evaluation activity will likely require additional resources and enforcement incentives. Limited federal actions through grant incentives and selected reporting requirements provide a possible means of stimulating programs to participate in national harmonization efforts.