Cardiac and behavioral responsivity to tactile stimulation in premature and full-term infants.

Attempted to determine whether psychophysiological differences exist between prematurely born and full-term infants in their responsivity to tactile stimulation and in their ability to discriminate among different intensities of such stimulation. The performance of 20 full-term neonates in active sleep was compared with that of 20 premature infants of comparable conceptional age (average, 38.5 wks). Whereas the full-term Ss showed both behavioral responsiveness and heart rate acceleration to the stronger levels of stimulation, the premature Ss showed weaker behavioral responses and no significant cardiac response. Even on those trials where the premature infants did show strong behavioral response, their cardiac response was smaller than that of the full-term infants. A significant sex difference for premature Ss indicated that the lower behavioral responsiveness was due mainly to males. Issues raised were whether the lack of cardiac responsivity in the premature infant is secondary to his/her heightened level of autonomic arousal whether it reflects a lack of integration between motor and autonomic systems. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A model for assessing the development of preterm infants as a function of gestational, conceptional, or chronological age.

Developed a mathematical model to deal with the longitudinal data of a new neurobehavioral assessment procedure for preterm infants ranging between 25 and 35 wks conceptional age. The model's analytic procedure permits the assessment of the differential effects of the Ss' chronological, conceptional, and gestational ages, birth weight, and other factors of interest on infant performance. Furthermore, it facilitates estimation of catch-up time (i.e., that CA at which the effects of differential gestational age on a particular test response would disappear). Using data on 22 preterm infants (gestational ages 25–32 wks), the model's use is illustrated by application to cluster scores of visual alertness, active tone, a cluster of miscellaneous maturity items, and irritability and/or hypertonicity, all of which in a pilot study reflected clear developmental trends. The potential usefulness of the model for clarifying methodological, developmental, clinical, and remedial issues are discussed. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erratum to Rose, Schmidt, and Bridger.

Reports an error in the original article by by Susan A. Rose, Katalin Schmidt, and Wagner H. Bridger (Developmental Psychology, 1976, Vol. 12, No. 4, pp. 311-320). In the article, the Method section and the Results section were placed in the wrong order. The correction is listed here. (The following abstract of this article originally appeared in record 1976-25557-001.) Attempted to determine whether psychophysiological differences exist between prematurely born and full-term infants in their responsivity to tactile stimulation and in their ability to discriminate among different intensities of such stimulation. The performance of 20 full-term neonates in active sleep was compared with that of 20 premature infants of comparable conceptional age (average, 38.5 wks). Whereas the full-term Ss showed both behavioral responsiveness and heart rate acceleration to the stronger levels of stimulation, the premature Ss showed weaker behavioral responses and no significant cardiac response. Even on those trials where the premature infants did show strong behavioral response, their cardiac response was smaller than that of the full-term infants. A significant sex difference for premature Ss indicated that the lower behavioral responsiveness was due mainly to males. Issues raised were whether the lack of cardiac responsivity in the premature infant is secondary to his/her heightened level of autonomic arousal whether it reflects a lack of integration between motor and autonomic systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory–visual responsiveness in full-term and preterm infants.

Compared older preterm and full-term infants in their response to objects in a dynamic multimodal context. In Study I, 67 12-wk-old full-term infants and 29 preterm infants (mean age 90 days) served as Ss. After familiarization with a silent moving object, full-term Ss recognized the object when it was stationary. When sound accompanied the moving object during familiarization, full-term Ss showed increased attention to the object but no subsequent recognition of that object. Neither high- nor low-risk preterms, at a comparable conceptional age, recognized the objects under any condition, but the low-risk preterms did show greater attention to the moving objects with sound. In Study II, 43 preterm Ss were tested approximately 6 mo after their estimated term date. The performance of the low-risk preterms was the same as that of full-terms; that is, through differential responding, they demonstrated association of an object and sound. In contrast, the high-risk preterms showed no differential looking. Thus both low- and high-risk preterms showed less differential responding than did normal full-terms at 3 mo, but at 6 mo only the high-risk preterms were different from the full-terms. Results suggest that the high-risk preterms are at a disadvantage for learning about the dynamic and multimodal aspects of their environment. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delayed maturation of Hering-Breuer inflation reflex activity in preterm infants

We have previously shown that the strength of the Hering-Breuer inflation reflex (HBIR) diminishes between 2 and 12 mo of age in full-term babies. The purpose of this study was to determine whether the onset of this decline had commenced by 3 to 4 mo of age in healthy full-term infants and whether preterm delivery influences the pattern of maturation. Serial measurements of HBIR activity using the end-inspiratory occlusion technique were made in 25 preterm and 27 full-term infants at matched postnatal and postconceptional ages during the first 6 mo of life. Although similar levels of reflex activity were observed at birth (mean +/- SD of 101.2% +/- 42.4% in preterm, and 101.0% +/- 33.9% in full-term infants), by 40 wk postconceptional age (PCA) (i.e., term equivalent) HBIR activity (mean +/- SD) had increased to 121.7% +/- 51.2% in preterm infants, which was significantly greater than that in full-term infants of similar PCA (95% CI of difference: 0.2; 41.2%). By 15 wk postnatal age (PNA), HBIR activity had decreased to 68.8% +/- 26.6% in full-term infants, but remained significantly higher in those delivered prematurely (87.8% +/- 32.7%). However, when measurements were repeated at approximately 4 mo after the expected rather than actual date of delivery, these differences were no longer evident (95% CI difference preterm-full-term: -21.2; 3.8%). This study suggests that important transitions in respiratory control mechanisms occur between 8 and 15 wk PNA in full-term infants and that these changes are delayed in preterm infants.     

Cortical response of preterm infants to phonetic and nonphonetic speech stimuli.

Auditory evoked responses (AERs) were recorded from left and right hemispheres of 11 male preterm infants (mean conceptional age 35.9 wks) in response to synthesized speech syllables and their nonphonetic and nonspeech analogs. Discrete components of the scalp-recorded AERs to these different stimuli were isolated and identified. One component reflected the presence of a left hemisphere mechanism that was sensitive to differences in phonetic and nonphonetic transitional characteristics. Other components of the AER were identified as sensitive to hemisphere differences and formant bandwidth changes. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-modal transfer in 6-month-old infants.

Investigated in 4 studies with 101 infants 25.5–32 wks of age the ability of Ss to transfer information about shape across modalities. Ss were familiarized either orally or tactually and then tested for visual recognition memory. In Exp I, Ss failed to show evidence of cross-modal transfer on any of the tasks (1 oral–visual, 2 tactual–visual). When familiarization times were increased from 30 to 60 sec in Exp II, Ss showed evidence of transfer on both tactual–visual tasks. Exp III eliminated the 5–7 sec delay that generally intervenes between the familiarization and test phase. Ss were permitted to retain the stimulus in their hand (or mouth) during the test phase while simultaneously viewing a novel stimulus and a duplicate of the familiar stimulus. This modification resulted in successful transfer on 1 of the 2 tactual–visual tasks. Ss did not show evidence of transfer on the oral–visual problem in any of these studies, despite evidence from Exp IV that they could visually discriminate the paired stimuli used in these tasks and that they showed recognition memory when familiarization and testing were both visual. Results suggest that, although cross-modal transfer of information about shape is present among 6-mo-olds, it is a less robust phenomenon than that seen in older infants. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allelotype influence at glutathione S-transferase M1 locus on breast cancer susceptibility

PURPOSE: To compare development of visual acuity and binocular vision in preterm and full-term infants in a prospective study that used testers masked to subject's gestational age. METHODS: Seventy-nine healthy full-term infants, mean gestational age 40 weeks, and 18 low-risk preterm infants, mean gestational age 33 weeks, were examined biweekly between the 44th and 54th weeks of postmenstrual age. Ocular alignment, convergence, fusion, grating acuity, and onset of optokinetic nystagmus (OKN) were assessed at each examination. RESULTS: The mean postnatal ages of onset of ocular alignment, convergence, fusion, grating acuity to 1.6 cycles per degree, and OKN from temporal to nasal and nasal to temporal were, respectively, 5, 7, 7, 11, 6, and 9 weeks for the full-term and 12, 13, 14, 18, 13, and 16 weeks for the preterm infants. The mean postmenstrual ages of onset for the corresponding parameters were 46, 48, 48, 51, 46, and 50 weeks for full-term and 46, 47, 48, 52, 47, and 49 weeks for preterm infants. The onset of all parameters was earlier in full-term infants than in preterm infants of the same postnatal age (P < or = 0.0001). However, no differences were found when the parameters were compared at postmenstrual ages. CONCLUSIONS: Additional visual experience of preterm infants does not influence development of visual acuity or binocular vision during the first months of life as measured from the time of conception.     

Cardiac and behavioral responses to repeated tactile and auditory stimulation by preterm and term neonates.

Auditory stimuli (a buzzer and rattle) and a tactile stimulus (a plastic filament) were repeatedly presented to 18 term and 18 preterm infants. Both groups initially responded to all stimuli with increased limb movements and heart rate acceleration. However, only the term infants responded to stimulus repetition by decreasing both cardiac and behavioral responses. In addition, they differentially responded to the 3 stimuli and showed response recovery in both systems. Since a behavioral response decrement was observed without a cardiac response decrement in the preterm group, a 2nd experiment was conducted. Heart rate change during the sucking activity of Exp II revealed an integration between autonomic and motor responsivity of preterm infants comparable to that of term newborns. The lack of cardiac–behavioral response integration during Exp I is discussed in the context of state differences between preterm and term infants as well as potential immaturity or some insult experienced by the preterm infants. The stimulus discrimination and habituation demands of Exp I may have overtaxed the preterm infants' ability to maintain response integration. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of preterm and full-term infant ability on AB, recall memory, transparent barrier detour, and means-end tasks

10 preterm and 10 full-term infants were tested longitudinally from 28 to 60 weeks of age on a modified version of the AB task, a nonreaching AB task, a Barrier Detour task, a Means-End task, and Perseveration in the Means-End task. Results show that age-corrected (age since conception) premature infants tolerated longer delays than full-term infants on the modified and nonreaching AB tasks. However, when compared by chronological age (age since birth), there were no group differences on either the reaching or nonreaching AB task. No group differences were found on Barrier Detour, Means-End, or Perseveration in either the age-corrected or chronological age comparisons. The results suggest that the function that mediates modified AB performance is one of memory and not of perseveration or means-end ability. Further, these findings suggest that current proposals about brain development based on single samples of infants may be tenuous. Finally, the results of this study suggest that development of the brain structure(s) that mediate modified AB performance is strongly influenced by experience in the postnatal environment.     

Infant auditory discrimination in preterm and full-term infants as a predictor of 5-year intelligence.

Examined the relation between responsiveness to auditory novelty in full-term and preterm infants at 4 mo and subsequent intellectual performance at 5 yrs of age. At 4 mo, cardiac response to repetitive and novel auditory stimulation was assessed using a variable-trials habituation procedure for 9 full-term and 19 preterm infants. Ss were followed until the age of 5 yrs, and intellectual performance was measured using the Stanford-Binet Intelligence Scale. A statistically significant correlation of .60 was found between infant novelty response scores and 5-yr intelligence scores. Mother's education also related to 5-yr performance, although not significantly when the novelty response was partialed out. Results suggest that measures of early perceptual-memory development may reflect early cognitive processes necessary for later intellectual performance. Within the preterm group, there was a sample of male infants with below-average intelligence at 5 yrs. These Ss failed to respond to novelty, and their mothers had not completed high school. Thus, a subsample of high-risk Ss can be identified early in life. A significant positive relation was also found between scores on the Bayley Scales of Infant Development and intelligence at 5 yrs of age. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation of young infants' reaching behavior to stimulus distance and solidity.

The reaching behavior of 12 infants in the presence of solid objects and pictures of objects placed within and beyond possible contact distance was videotaped in 3 sessions at 15, 19, and 24 wks of age. From 15 wks onward the Ss adjusted their reaching behavior to changes in the physical distance of stimuli. However, infants who attempted to manipulate the solid objects tended to reach for pictured objects in the same way. The different amounts of visual attention Ss paid to objects and pictures indicated that they could visually discriminate between the flat and solid stimuli, but it seemed this capacity for depth perception could be obscured by the rather compulsive tendency of young infants to manipulate patterned surfaces situated within reach. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional maturation of cochlear active mechanisms and of the medial olivocochlear system in humans

The aim of this study was to investigate the functional development of cochlear active mechanisms and of the medial efferent olivocochlear system. Otoacoustic emissions (evoked and spontaneous) were recorded in 42 preterm neonates (conceptional age ranging form 33 to 39 weeks) and a control group of 20 young normal-hearing adults. Medial olivocochlear system activity was examined by coupling evoked otoacoustic emission recording to a contralateral stimulation. Otoacoustic emission recordings were carried out using the Otodynamic ILO88 software and hardware. The stimuli were unfiltered clicks and the contralateral stimulation was broad band noise of 50 and 70 dBSPL delivered by an Adam generator. The results revealed the presence of EOAEs and SOAEs from at least 33 weeks in humans, suggesting that the functional maturation of the outer hair cells is nearly complete at that age. The study further revealed that the contralateral stimulation had no effect on evoked otoacoustic emissions in preterm neonates. The lack of activity observed in medial olivocochlear system indicated functional immaturity here, at least before full-term birth.     

Learning in premature infants.

Examined instrumental learning in premature infants by using a teddy bear that "breathed" quietly at a rate that reflected the infant's respiration rate. At 33 wks conceptional age (CA), 45 infants were provided with a breathing bear (BRB) or a nonbreathing bear (NBRB). The baby was monitored by time-lapse video for 3-day periods at the beginning and end of a 2-wk intervention period. The BRB babies decreased their latency to contact the bear over time, whereas the NBRB babies showed the opposite pattern. For the BRB babies, decreased contact latencies were correlated with increased total contact and increased contact frequencies. Thus, by 35 wks CA, premature infants learned to find and make contact with a reinforcing source of stimulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of attention in preterm infants

The quality of the awake state and attention in preterm infants has been evaluated by rating indices of attention such as widening of the eye, type of fixation, brightening, scanning, and cessation of sucking measured during visual fixation of patterns. Twenty-six infants ranging from 28 to 32 weeks' gestation at birth (mean, 31 weeks) were tested from one to four weeks postnatally until 36 weeks' gestation. Indices of attention were rated on a scale of 4 with an optimal mean index of 4. A progressive increase in behaviors associated with fixation of visual stimuli has been shown from 32 to 36 weeks of conceptual age. Mean scores ranged from 0.7 at 31 weeks' gestation to 1.8 at 34 weeks' and 2.7 at 36 weeks' gestation. The possibility therefore exists that by as early as 31 to 32 weeks from conception the human brain may be capable of waking states and thus able to process some sensory stimulation.rease in behaviors associated with fixation of visual stimuli has been shown from 32 to 36 weeks of conceptual age. Mean scores ranged from 0.7 at 31 weeks' gestation to 1.8 at 34 weeks' and 2.7 at 36 weeks' gestation. The possibility therefore exists that by as early as 31 to 32 weeks from conception the human brain may be capable of waking states and thus able to process some sensory stimulation.     

Attention and recognition memory in the 1st year of life: A longitudinal study of preterm and full-term infants.

Several aspects of visual attention and their implications for recognition memory were examined in a longitudinal sample of full-term and preterm (birth weight?     

Impact of premature birth on the development of the infant in the family.

This article describes effects of the birth of a premature infant on the family system and focuses on how problems associated with premature birth such as infant illness, hospitalization, and immaturity can place the family at risk. New data are presented describing differences in the behavior of preterm and full-term infants and in the feelings of mothers toward their infants at 12 months. Mothers of preterm infants reported feeling overprotective toward them, were less willing to leave them with sitters, and believed that their birth had an initially negative effect on the family. Preterm infants showed less exploratory play and stayed closer to their mothers during free play. The fact that these differences are not reflected in patterns of attachment, a key measure of the mother–infant relationship, is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extreme prematurity in healthy 5-year-old children: a re-analysis of sex effects on event-related brain activity

A male disadvantage has been reported in several outcome studies of children born preterm. Twenty-two healthy premature children (10 girls, 12 boys) born between 25 and 28 weeks of gestation and 20 controls born full-term (10 boys, 10 girls) were matched on socioeconomical status and age. Event-related potentials (ERPs) were recorded by using 14 electrodes in a visual oddball task, with 75% frequent and 25% rare stimuli. This task elicited a larger P3 to the rare than to the frequent stimuli, with a prominent parietocentral localization. However, the amplitude was larger in full-term boys than in full-term girls, a difference that was not observed between preterm boys and preterm girls, especially to targets and on the central electrodes. In addition, the preterm group was characterized by a frontal slow wave larger in boys than in girls. In these prematures, the lack of the sex-related difference may be accounted by differences in the strength of the neuronal generators in males, as they might have been affected by the high level of androgens by the fetal testis under the control of placental gonadotropes during the first two thirds of gestation.     

Gender-specific frequency of background somatic mutations at the hypoxanthine phosphoribosyltransferase locus in cord blood T lymphocytes from preterm newborns

Limited information is available regarding the frequency, spectrum, and clinical relevance of somatic mutations in the developing fetus. The goal of this study was to determine somatic mutant frequencies (Mfs) at the hypoxanthine phosphoribosyltransferase (HPRT) reporter gene in cord blood T lymphocytes from preterm infants to gain insight into in utero mutational events. Mf determinations were made by using the HPRT T cell cloning assay on cord blood samples from 52 preterm infants. Natural logarithm Mfs (lnMfs) from preterm infants were compared with results from our database for full-term infants. Our analysis revealed higher lnMfs in cord blood T lymphocytes from preterm compared with full-term infants (P = 0.008). In addition, preterm females had significantly higher lnMfs compared with full-term females (P < 0.001), whereas preterm males were found to have significantly lower lnMfs than preterm females (P = 0.005). Regression analyses also demonstrate a significant relationship between lnMf and gestational age for preterm females that does not exist for preterm males. These results demonstrate the gender-specific association between Mf and age in humans.     

Ligation of medically refracted patent ductus arteriosus (PDA) in an extremely low body weight premature infant

Medically refracted patent ductus arteriosus (PDA) in an extremely low birth weight (ELBW) preterm (gestation 24 weeks 2 days) infant was successfully ligated under general anesthesia in the neonatal intensive care unit (NICU). Pharmacological agents are more effective to close PDA in preterm infants than in full-term infants, although within 48 h three doses of indomethacin were not sufficient to close PDA in this case. At the age of 69 h the infant developed severe symptoms including bradycardia, systemic hypotension, pulmonary hypertension, diastolic steal (reverse distal aorta flow velocity), and anuria. A PDA ligation was thus performed surgically at 72 h of age. General anesthesia and surgical stress were tolerated by this 531 g infant. Postoperatively all symptoms improved dramatically and the general conditions were stable. On the 38th day the endotracheal tube was extubated and on the 50th day nasogastric milk feeding was started. The oxygen supply was weaned on the 78th day. Growth and development until 6 months were within the normal range of very low birth weight infants. A surgical ligation as early as possible in medically refracted PDA in an ELBW infant is thus considered to be a safe and effective treatment. It prevents the development of further complications of cardiopulmonary vascular problems. Color Doppler echocardiography can reliably measure the PDA size, flow velocity, and hemodynamic changes of persistent PDA, even in tiny infants.