The development of reaching behavior in low-risk preterm infants

This longitudinal study investigated the development of reaching behavior in the seated position in preterm infants at the ages of 5–7 months by analyzing kinematic variables (straightness and adjustment indexes, movement unit, mean and final velocities). The correlation between kinematic variables and grasping was verified. The participants were nine low-risk preterm infants with no cerebral lesions. Ten fullterm infants served as control. In both groups, kinematic variables remained unchanged over age, except for the adjustment index, which was higher at 6 months in the preterm group. Successful grasping increased in both groups over age and it was shown to be negatively correlated with mean velocity in the preterm infants. At the ages of 6 and 7 months, preterms showed lower mean and final velocities and higher adjustment index when compared with fullterms. The relative constancy in the kinematic variables suggests that, after having explored the action possibilities during the acquisition phase, the infants selected an adaptative pattern to perform the reaching movements. Slower movements and greater adjustments may be functional strategies of preterms to achieve successful grasps.     

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.     

Potential underlying mechanisms for greater weight gain in massaged preterm infants

In this paper, potential underlying mechanisms for massage therapy effects on preterm infant weight gain are reviewed. Path analyses are presented suggesting that: (1) increased vagal activity was associated with (2) increased gastric motility, which, in turn, was related to (3) greater weight gain; and (4) increased IGF-1 was related to greater weight gain. The change in vagal activity during the massage explained 49% of the variance in the change in gastric activity. And, the change in vagal activity during the massage explained 62% of the variance in the change in insulin. That the change in gastric activity was not related to the change in insulin suggests two parallel pathways via which massage therapy leads to increased weight gain: (1) insulin release via the celiac branch of the vagus; and (2) increased gastric activity via the gastric branch of the vagus.     

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.     

Moderate versus light pressure massage therapy leads to greater weight gain in preterm infants

Sixty-eight preterm infants (M GA = 30 weeks) were randomly assigned to a moderate or to a light pressure massage therapy group to receive 15 massages three times per day for 5 days. Behavior state, stress behaviors and heart rate were recorded for 15 min before and during the first 15-min therapy session. Weight gain was recorded over the 5-day therapy period. The moderate versus light pressure massage group gained significantly more weight per day. During the behavior observations the moderate versus light pressure massage group showed significantly lower increases from the pre-session to the session recording on: (1) active sleep; (2) fussing; (3) crying; (4) movement; and (5) stress behavior (hiccupping). They also showed a smaller decrease in deep sleep, a greater decrease in heart rate and a greater increase in vagal tone. Thus, the moderate pressure massage therapy group appeared to be more relaxed and less aroused than the light pressure massage group which may have contributed to the greater weight gain of the moderate pressure massage therapy group.     

The relationship between sleep problems and working memory in children born very preterm

In two studies, the relationship between sleep and working memory performance was investigated in children born very preterm (i.e., gestation less than 32 weeks) and the possible mechanisms underlying this relationship. In Study 1, parent-reported measures of snoring, night-time sleep quality, and daytime sleepiness were collected on 89 children born very preterm aged 6 to 7 years. The children completed a verbal working memory task, as well as measures of processing speed and verbal storage capacity. Night-time sleep quality was found to be associated with verbal working memory performance over and above the variance associated with individual differences in processing speed and storage capacity, suggesting that poor sleep may have an impact on the executive component of working memory. Snoring and daytime sleepiness were not found to be associated with working memory performance. Study 2 introduced a direct measure of executive functioning and examined whether sleep problems would differentially impact the executive functioning of children born very preterm relative to children born to term. Parent-reported sleep problems were collected on 43 children born very preterm and 48 children born to term (aged 6 to 9 years). Problematic sleep was found to adversely impact executive functioning in the very preterm group, while no effect of sleep was found in the control group. These findings implicate executive dysfunction as a possible mechanism by which problematic sleep adversely impacts upon cognition in children born very preterm, and suggest that sleep problems can increase the cognitive vulnerability already experienced by many of these children.     

Preterm infants show reduced stress behaviors and activity after 5 days of massage therapy

Preterm infants residing in an NICU were randomly assigned to a massage therapy or to a control group. The preterm infants in the massage therapy group received three 15-min massages each day for 5 consecutive days, with the massages consisting of moderate pressure stroking to the head, shoulders, back, arms and legs and kinesthetic exercises consisting of flexion and extension of the limbs. Infant stress behaviors and activity were recorded on the first and last day of the study. Preterm infants receiving massage therapy showed fewer stress behaviors and less activity from the first to the last day of the study. The findings suggest that massage has pacifying or stress reducing effects on preterm infants, which is noteworthy given that they experience numerous stressors during their hospitalization.     

Two-month-olds' attention and affective response to maternal still face: a comparison between term and preterm infants in Taiwan

Maternal still face is a robust experimental procedure designed to examine infants’ sensitivity to social contingency and reactivity to its violation. To extend earlier research on the still-face effect on term infants in Western cultures, the present study compared Taiwanese term and preterm infants’ attention and affective response to and recovery from a modified maternal still-face procedure that used an additional still-face reengagement sequence at 2 months of age (corrected age for preterm infants). Infants’ gaze and facial affect were coded from videos. Results showed that preterm infants were as sensitive as term infants to the interruption to social contingency. Both groups of infants reacted with decreased gaze and positive affect across episodes, together with a decreased latency to gaze aversion and an increased latency to positive affect. Both term and preterm infants also demonstrated a W-shaped pattern of decline-followed-by-recovery in their latency to negative affect. However, compared to term infants, preterm infants became distressed faster and stayed in a negative affective state longer after the first exposure to maternal still face. Effects of prematurity on infant attention and affect regulation were discussed. Implications of preterm infants’ heightened affective negativity to mild stress for intervention studies were also addressed.     

Vocal responsiveness of preterm infants to maternal infant-directed speaking and singing during skin-to-skin contact (Kangaroo Care) in the NICU

Vocalizations of full-term newborns occur in a short latency time during the neonatal period. Contingent response time of preterm babies is still unknown. An increase of preterm babies’ vocalizations following exposure to parental speech was also observed. Mothers and babies co-modulate their vocalizations in preterm dyads. Purpose: To observe temporal features of maternal and infants’ vocalizations in speaking and singing conditions in preterm dyads. Methods: In a NICU mothers (N = 36) were invited to speak and to sing to their preterm infants during Kangaroo Care. Microanalysis of temporal units were performed with ELAN Software. Results and conclusions: Preterm infants vocalize less often while their mothers speak and sing than during baseline and their vocalizations tend to be more alternating in the speaking condition and more overlapping in the singing condition. It is also concluded that preterm infants take more time to respond to maternal speaking than to maternal singing.     

Prem Baby Triple P a new parenting intervention for parents of infants born very preterm: acceptability and barriers

Over 10% of preterm infants develop major disabilities, 50% develop behavioural problems and 40% need special education ( [Huddy et al., 2001] and [0185] ). Prem Baby Triple P is a new variant of the Positive Parenting Program (Triple P) adapted specifically for parents of very preterm infants. The aim of this study is to assess the acceptability of Prem Baby Triple P to parents of infants born preterm and to test whether parental attributions and parental perception of infant health/developmental status are barriers to intervention acceptability. One hundred and twenty-three parents of preterm infants participated, 83 parents of very preterm infants and 40 parents of preterm infants. In addition, 32 parents of term infants participated as a comparison group. The acceptability of Prem Baby Triple P was moderately high and did not differ significantly across the three groups. Parental attributions were not found to be barriers to intervention acceptability and parental perceptions that their infant is less healthy/developmentally delayed facilitated Prem Baby Triple P acceptance in parents of infants born very preterm. This suggests that the planned Prem Baby Triple P content is acceptable to parents of infants born very preterm and sensitised to medical and developmental issues. These findings, as social validation data, will contribute towards the further development of Prem Baby Triple P and a future randomised controlled trial.     

Attachment representations in mothers of preterm infants

The aim of the study was to assess attachment representations in mothers of preterm infants using the Working Model of Child Interview (WMCI) at the 12 months of the infant's corrected age. In addition, the relation between WMCI representation categories and the Edinburgh Postnatal Depression Scale score at 6 months of the infant's corrected age was studied. There were 38 mothers of preterm infants (<1500 g or <32 gestational weeks) and 45 mothers of full-term infants. The results showed no differences between the study groups in the distribution of the three main representation categories (balanced, disengaged and distorted). However, there were qualitative differences in representations between the groups. Furthermore, maternal depression symptoms were associated with distorted representation category. We suggest that despite the qualitative differences in the mothers’ representations, mothers of preterm infants are as likely to form balanced attachments with their infants as mothers of full-term infants.     

Early interactive behaviours in preterm infants and their mothers: Influences of maternal depressive symptomatology and neonatal birth weight

The study evaluated the quality of preterm infant–mother interactions, considering severity of birth weight (ELBW and VLBW) and maternal depression, compared to full term babies. 69 preterm infants (29 ELBW and 40 VLBW) and 80 full-term (FT) infants and their mothers were recruited. At 3 months of corrected age, the quality of mother–infant interaction was evaluated through Global Rating Scales; moreover, infant level of development and maternal depression were assessed through Griffith Development Mental Scales and Edinburgh Postnatal Depression Scale. Results showed adequate sensitivity in preterm infants’ mothers and higher involvement with their infants, compared to full term mothers, but ELBW ones exhibited an intrusive interactive pattern and a higher prevalence of depressive symptoms. The study underlined the relevance of paying special attention to both ELBW infants and their mothers, in order to support the parenting role and the co-construction of early interactions.     

Effect of developmental care for very premature infants on neurodevelopmental outcome at 2 years of age

BackgroundTo determine the effect of developmental care on neurodevelopmental outcome in formerly preterm infants at a corrected age of 2 years.MethodsA prospective phase-lag study was performed at an Austrian neonatal intensive care unit (NICU). From January 2003 to December 2005 (study period of conventional care) and January 2007 to December 2009 (study period of developmental care), we enrolled all infants born in Tyrol at less than 32 weeks of gestation. During this period a total of 261 of 359 preterm infants (participation rate 72.7%) completed the follow-up visit at 2 years of age; there were 124 children in the conventional and 137 in the developmental care group. The association between developmental care and delayed motor or mental development (Bayley Scales of Infant Development II; psychomotor or mental developmental index <85) was analyzed by means of logistic regression analysis at a corrected age of 24 months.ResultsChildren in the developmental care group showed less psychomotor delay than did those in the control group (developmental care group: 16.1%, conventional care group 27.4%; adjusted odds ratio 0.37 [95% confidence interval: 0.19–0.74], P = 0.005). Not smoking in pregnancy and higher gestational age were also significant predictors for a better psychomotor outcome at 2 years of age. Regarding cognitive outcome, no significant difference was observed between these two groups.ConclusionOur data implicate that developmental care may result in an improved 2-year psychomotor outcome in formerly preterm infants.     

Emotional and neuroendocrine regulation in very preterm and full-term infants at six months of age

Emotional and neuroendocrine regulation have been shown to be associated. However, results are inconsistent. This paper explores the functioning and relationships between these two systems in 54 healthy preterm and 25 full-term born infants at six months of age. Results showed significant differences between very preterm and full-term children in emotional intensity and regulation, as well as in neuroendocrine regulation. No evidence of an association between neuroendocrine and emotional regulations was found. Results suggest a possible delay in the maturation of the neuroendocrine system as well as in emotional regulation in very preterm infants.     

Effects of preterm birth and gender on temperament and behavior in children

The aim of the present study was to assess the direct and interactive effects of premature birth and gender on temperament and behavioral problems in 80 children aged 18–36 months. The sample was composed of children born preterm (PT; n = 44) and children born full-term (FT; n = 36). The children's mothers completed temperament (ECBQ) and behavioral problem (CBCL 1.5–5) assessments. Analyses of variance (ANOVA 2 × 2) were performed. With regard to temperament, PT children exhibited significantly higher scores on high-intensity pleasure and perceptual sensitivity and lower scores on discomfort, cuddliness, and Attentional Focusing compared with FT children. Girls scored higher on fear and discomfort compared with boys. With concern to behavioral problems, PT children scored higher on attention problems compared with FT children. No interactive effect of premature birth and gender on temperament or behavioral problems was found.     

Effortful control,positive emotional expression,and behavior problems in children born preterm

The present study focused on the role of high effortful control in the expression of positive emotion and development of behavior problems in children born preterm (mean gestational age = 31.4 weeks). Using data from a prospective longitudinal study, the present study assessed effortful control and behavior problems at 24 and 36 months and positive emotional expression at 24 months in a sample of 173 children born preterm. Less positive emotional expression was associated with higher effortful control for boys but not girls. Higher effortful control was associated with fewer total behavior problems, but this relation was attenuated when socioeconomic assets were included in the model. More socioeconomic assets were associated with fewer behavior problems for both boys and girls and higher effortful control for girls. Socioeconomic assets appear to be an important factor in the development of effortful control and behavior problems in children born preterm regardless of gender, whereas positive emotional expression was important for boys. Future intervention research should examine fostering adaptive levels of effortful control in high-risk populations as a means to facilitate resilience processes.     

The breathing bear with preterm infants: Effects on sleep,respiration, and affect

This study investigated the sleep/wake states, respiration, and affective behaviors of premature infants who were provided à “breathing” bear in the isolette from 33 to 35 weeks conceptional age (CA). The Breathing Bear is à source of rhythmic stimulation that is optional for the infants. Its “breathing” reflects the breathing rate of the individual infant. At 33 weeks CA, 27 premature infants were provided à Breathing Bear (BrBr) and 26 were given à Non-Breathing Bear (N-BrBr). At 35 weeks, interfeed observations for an average of 1.7 hours were made of the babies' states and state-specific behaviors, along with respiration recordings. By 35 weeks, the BrBr babies showed less wakefulness, more quiet sleep, fewer startles in quiet sleep, and less crying than the N-BrBr babies. In addition, they were more likely to smile and N-BrBr babies were more likely to grimace in active sleep. These findings replicate and extend previous reports of effects of the Breathing Bear on neurobehavioral organization. They also suggest that less negative affect is expressed by the BrBr babies; and they point to the importance of future study of preterm infants' affective expressions, both in sleep and in waking.     

Visual orienting and attention deficits in 5- and 10-month-old preterm infants

Cognitive outcomes for children born prematurely are well characterized, including increased risk for deficits in memory, attention, processing speed, and executive function. However, little is known about deficits that appear within the first 12 months, and how these early deficits contribute to later outcomes. To probe for functional deficits in visual attention, preterm and full-term infants were tested at 5 and 10 months with the Infant Orienting With Attention task (IOWA; Ross-Sheehy, Schneegans and Spencer, 2015). 5-month-old preterm infants showed significant deficits in orienting speed and task related error. However, 10-month-old preterm infants showed only selective deficits in spatial attention, particularly reflexive orienting responses, and responses that required some inhibition. These emergent deficits in spatial attention suggest preterm differences may be related to altered postnatal developmental trajectories. Moreover, we found no evidence of a dose-response relation between increased gestational risk and spatial attention. These results highlight the critical role of postnatal visual experience, and suggest that visual orienting may be a sensitive measure of attentional delay. Results reported here both inform current theoretical models of early perceptual/cognitive development, and future intervention efforts.