Infants' learning about words and sounds in relation to objects.
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In acquiring language, babies learn not only that people can communicate about objects and events, but also that they typically use a particular kind of act as the communicative signal. The current studies asked whether 1-year-olds' learning of names during joint attention is guided by the expectation that names will be in the form of spoken words. In the first study, 13-month-olds were introduced to either a novel word or a novel sound-producing action (using a small noisemaker). Both the word and the sound were produced by a researcher as she showed the baby a new toy during a joint attention episode. The baby's memory for the link between the word or sound and the object was tested in a multiple choice procedure. Thirteen-month-olds learned both the word-object and sound-object correspondences, as evidenced by their choosing the target reliably in response to hearing the word or sound on test trials, but not on control trials when no word or sound was present. In the second study, 13-month-olds, but not 20-month-olds, learned a new sound-object correspondence. These results indicate that infants initially accept a broad range of signals in communicative contexts and narrow the range with development. (+info)
Randomised controlled trial of low dose fentanyl infusion in preterm infants with hyaline membrane disease.
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AIM: To evaluate the effects of low dose fentanyl infusion analgesia on behavioural and neuroendocrine stress response and short term outcome in premature infants ventilated for hyaline membrane disease. METHODS: Twenty seven ventilated preterm infants were randomly assigned to receive a mean fentanyl infusion of 1.1 (0.08 SE) micrograms/kg/h for 75 (5) hours, and 28 untreated infants were considered a control group. A behavioural sedation score was used to assess the infants' behaviour. Urinary metanephrine and the normetanephrine:creatinine molar ratio were determined at 0, 24, 48 and 72 hours. Outcome data and ventilatory indexes were recorded for each infant. RESULTS: The fentanyl group showed significantly lower behavioural stress scores and O2 desaturations than controls and lower urinary concentrations of metanephrine and normetanephrine at 24, 48, 72 hours. The two groups showed no significant difference in ventilatory variables or short term outcome. CONCLUSIONS: A short course of low dose fentanyl infusion reduces behavioural sedation scores, O2 desaturations and neuroendocrine stress response in preterm ventilated infants. (+info)
Measurement of upper esophageal sphincter tone and relaxation during swallowing in premature infants.
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Upper esophageal sphincter (UES) motor function has not been previously evaluated in premature infants. The motor patterns associated with tonic activity and swallow-related relaxation of the UES were recorded for 1 h after completion of gavage feeding in 11 healthy preterm neonates (postmenstrual age 33-37 wk) with a micromanometric assembly, which included a sleeve sensor specifically adapted for UES recordings. A clearly defined UES high-pressure zone was observed in all premature infants studied. Resting UES pressure ranged from 2.3 to 26.2 mmHg and was higher during periods of irritability and apparent discomfort. During dry swallows, UES pressure relaxed from a resting pressure of 28.2 +/- 4.0 mmHg to a nadir of 1.1 +/- 3.3 mmHg. The mean UES relaxation interval (the time from relaxation onset to relaxation offset) was 0. 31 +/- 0.11 s. We conclude that in premature infants >/=33 wk postmenstrual age the motor mechanisms regulating UES resting pressure and the onset of UES relaxation are well developed. (+info)
Behavioral methods used in the study of long-chain polyunsaturated fatty acid nutrition in primate infants.
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Domains of behavior may be broadly categorized as sensory, motor, motivational and arousal, cognitive, and social. Differences in these domains occur because of changes in brain structure and function. Docosahexaenoic acid (DHA; 22:6-23) and arachidonic acid (AA; 20:4-26) are major structural components of the brain that decrease when diets deficient in the essential fatty acids (EFA) alpha-linolenic acid and linoleic acid are consumed. Early electrophysiologic and behavioral studies in EFA-deficient rodents showed behavioral effects attributable to lower-than-normal accumulation of DHA and AA in the brain. More recently, electrophysiologic and behavioral studies in EFA-deficient primate infants and analogous studies in human infants have been conducted. The human infants were fed formulas that could result in lower-than-optimal accumulation of long-chain polyunsaturated fatty acids (LCPUFAs) in the brain during critical periods of development. This article describes the behavioral methods that have been used to study primate infants. These methods may be unfamiliar to many physicians and nutritionists who wish to read and interpret the human studies. The behavioral outcomes that have been evaluated in LCPUFA studies represent only a fraction of those available in the behavioral sciences. Specific developmental domains have been studied less often than global development, even though studies of nonhuman primates deficient in EFAs suggest that the former provide more information that could help target the underlying mechanisms of action of LCPUFAs in the brain. (+info)
Skin conductance and the stress response from heel stick in preterm infants.
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AIM: To evaluate whether spontaneous skin conductance activity is an objective method for measuring the stress response to painful stimuli in premature infants. The number and amplitude of the waves and the baseline increase with the activity of the sympathetic nervous system. METHODS: In 20 preterm infants of gestational age >/= 29 weeks, behavioural state and spontaneous skin conductance activity variables were measured for three minutes before, during, and for three minutes after heel stick. RESULTS: The number of waves (p < 0.001), the amplitude of the waves (p = 0.001), and the level of the behavioural state (p < 0.001) increased during heel stick, and then decreased to levels found before the procedure. The baseline increased both during (p < 0.001) and after heel stick (p < 0.001), compared with levels before. CONCLUSION: Spontaneous skin conductance activity reflects the stress response to heel stick in premature infants from at least 29 weeks of gestational age. (+info)
Brief report: the Brazelton Neonatal Behavioral Assessment Scale detects differences among newborn infants of optimal health.
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OBJECTIVE: To determine whether the Brazelton Neonatal Behavioral Assessment Scale (NBAS) can detect behavioral differences in newborn infants of optimal health and, if such differences appear, also detect gender differences among those neonates. METHODS: Participants were a group of healthy Swedish neonates, 20 boys and 18 girls. The infants were assessed by the NBAS under standardized conditions at 48-72 hours of age, at the midpoint between two meals. RESULTS: All items except those in the dimensions Autonomic System and Motor System had a wide interquartile range. The trend was that girls had higher median item profiles, which means a higher level of functioning than boys. Four out of seven median values in the dimension Social Interactive Organization, as well as the median value in the self-quieting item in the dimension State Regulation, were significantly higher for girls. The interquartile range of the items seemed wider for boys than for girls. CONCLUSIONS: The results indicate behavioral variability among healthy neonates. Gender differences were also observed with girls showing higher levels of functioning than boys. (+info)
Parenting stress in mothers of very-low-birth-weight (VLBW) and full-term infants: a function of infant behavioral characteristics and child-rearing attitudes.
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OBJECTIVE: To examine the moderating effects of child-rearing attitudes on the relation between parenting stress and infant behavioral characteristics for mothers of very-low-birth-weight (VLBW) and full-term infants. METHODS: Fifty-six 9-month-old infants (23 VLBW and 33 full-term) and their mothers were the participants. Mothers completed measures of parenting stress, child-rearing attitudes, infant temperament, and infant behavioral problems. RESULTS: The VLBW infants had a higher frequency of behavioral problems, and their mothers reported more child health concerns than the mothers of the full-term infants. Regression analyses showed that the relation between parenting stress and infant distress was moderated at medium and high levels of parental strictness for only the VLBW infants. CONCLUSIONS: The amount of stress the mothers of the VLBW infants experienced was a result of the congruence between their infant's behavioral characteristics and their own child-rearing attitudes. (+info)
Regulation of milk intake after exposure to alcohol in mothers' milk.
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OBJECTIVE: Contrary to the folklore which claims that drinking alcohol during lactation benefits both mother and infant, previous research in our laboratory revealed that breastfed infants consumed significantly less milk during the immediate hours after their mothers' consumption of an alcoholic beverage. Because breastfed infants are clearly capable of regulating milk intake, the present study tested the hypothesis that infants would compensate for the diminished milk intake if their mothers then refrained from drinking alcohol. METHODS: A within-subjects design that controlled for time of day was implemented because of the great individual and daily variation in both milk composition and intake. To this end, 12 exclusively breastfed infants and their mothers were tested on 2 days separated by 1 week. Each woman drank a 0.3 g/kg dose of alcohol in orange juice on one testing day and orange juice alone on the other; the order was counterbalanced. The infants' behaviors were monitored for the next 16 hr, the first 4 hr of monitoring on each test day occurred at the Monell Center. The infants fed on demand and immediately before and after each feeding, infants were weighed without a change in clothing. RESULTS: Consistent with previous findings, infants consumed significantly less milk during the 4 hr immediately after exposure to alcohol in mothers' milk compared with the control condition. Compensatory increases in intake were then observed during the 8 to 16 hr after exposure when mothers refrained from drinking alcohol. CONCLUSIONS: These findings demonstrate that short-term exposure to small amounts of alcohol in mothers' milk produces distinctive changes in the infants' patterns of feeding. (+info)