Fleur Lejeune

The Manual Habituation and Discrimination of Shapes in Preterm Human Infants from 33 to 34+6 Post-Conceptional Age

Background Grasping at birth is well-known as a reflex in response to a stimulation of the palm of the hand. Recent studies revealed that this grasping was not only a pure reflex because human newborns are able to detect and to remember differences in shape features. The manual perception of shapes has not been investigated in preterm human infants. The aim of the present study was to investigate manual perception by preterm infants. Methodology/Principal Findings We used a habituation/reaction to novelty procedure in twenty-four human preterm infants from 33 to 34+6 post-conceptional age. After habituation to an object (prism or cylinder) in one hand (left or right) in a habituation phase, babies were given either the same object or the other (novel) object in the same hand in a test phase. We observed that after successive presentations of the same object, a decrease of the holding time is observed for each preterm infant. Moreover, a significant increase of the holding time is obtained with the presentation of the novel object. Finally, the comparison between the current performance of preterm infants and those of full-term newborns showed that preterm babies only had a faster tactile habituation to a shape. Conclusion/Significance For the first time, the results reveal that preterm infants from 33 to 34+6 GW can detect the specific features that differentiate prism and cylinder shapes by touch, and remember them. The results suggest that there is no qualitative, but only quantitative, difference between the perceptual abilities of preterm babies and those of full-term babies in perceiving shape manually.

Tactile Sensory Capacity of the Preterm Infant: Manual Perception of Shape From 28 Gestational Weeks

OBJECTIVE: Recent studies have shown that from the postconceptional age of 33 weeks, preterm infants are able to memorize tactile information about the shape of an object by using their hands, and can detect differences with another shape. This study aimed to investigate tactile abilities earlier on in development, in very preterm and mildly preterm human infants. METHODS: Infants were assigned to 2 groups according to postconceptional age: very preterm (before 32 weeks) and mildly preterm (from 32 to 33+6 weeks). The test consisted of the repeated presentation of an object (prism or cylinder) in the left hand. The experiment was conducted in 3 phases: habituation (repeated presentation of the same object), discrimination (presentation of a novel object), followed by recognition (presentation of the familiar object). RESULTS: Forty-eight newborns were recruited (24 very preterm; 24 mildly preterm). During habituation, each infant showed a decrease in the holding time of the object. Then, when a novel shape was put into the preterm newborn’s hand, holding time increased. Finally, when the familiar shape was presented again, the holding time decreased. Preterm infants can memorize by touch specific features that differentiate prism and cylinder shapes, discriminate between them, and recognize them after interference. CONCLUSIONS: From 28 weeks, and from the first days of life, the preterm newborn is endowed with tactile sensory capacities. The tactile stimulations that are presented to preterm infants during their hospitalization should be adapted while respecting their sleep-wake rhythms.

Emotional and effortful control abilities in 42-month-old very preterm and full-term children

BACKGROUND Very preterm (VP) infants are at greater risk for cognitive difficulties that may persist during school-age, adolescence and adulthood. Behavioral assessments report either effortful control (part of executive functions) or emotional reactivity/regulation impairments. AIMS The aim of this study is to examine whether emotional recognition, reactivity, and regulation, as well as effortful control abilities are impaired in very preterm children at 42 months of age, compared with their full-term peers, and to what extent emotional and effortful control difficulties are linked. STUDY DESIGN Children born very preterm (VP; < 29 weeks gestational age, n=41) and full-term (FT) aged-matched children (n=47) participated in a series of specific neuropsychological tests assessing their level of emotional understanding, reactivity and regulation, as well as their attentional and effortful control abilities. RESULTS VP children exhibited higher scores of frustration and fear, and were less accurate in naming facial expressions of emotions than their aged-matched peers. However, VP children and FT children equally performed when asked to choose emotional facial expression in social context, and when we assessed their selective attention skills. VP performed significantly lower than full terms on two tasks of inhibition when correcting for verbal skills. Moreover, significant correlations between cognitive capacities (effortful control) and emotional abilities were evidenced. CONCLUSIONS Compared to their FT peers, 42 month-olds who were born very preterm are at higher risk of exhibiting specific emotional and effortful control difficulties. The results suggest that these difficulties are linked. Ongoing behavioral and emotional impairments starting at an early age in preterms highlight the need for early interventions based on a better understanding of the relationship between emotional and cognitive difficulties.

Sound Interferes with the Early Tactile Manual Abilities of Preterm Infants.

Premature birth is a sudden change of the sensory environment of a newborn, while their senses are still in development, especially in the stressful and noisy environment of the NICU. The study aimed to evaluate the effect of noise on the early tactile manual abilities of preterm infants (between 29 and 35 weeks PCA). Infants were randomly assigned to one of the two conditions: Silence and Noise. For each condition, two phases were introduced: a habituation phase (repeated presentation of the same object, prism or cylinder), followed by a test phase (presentation of the familiar or a novel object). In the Silence condition, they received the tactile habituation and test phases: In the Noise condition, they went through the same phases, while an alarm sounded. Sixty-three preterm infants were included. They displayed a strong and effective ability to memorize tactile manual information and to detect the difference between two shape features, but this ability seems to be impaired by the concomitant exposure to an alarm sound. This study is the first to highlight the effect of a negative stimulus on sensory functioning in premature infants. It reinforces the importance of developing environmental measures to lower the sound level in NICUs.

The effect of postnatal age on the early tactile manual abilities of preterm infants.

BACKGROUND Although preterm infants possess early tactile manual abilities, the influence of the postnatal experience has not yet been systematically examined. AIMS To investigate whether early tactile manual habituation, discrimination and recognition (following interference) of shape in preterm infants are modified by postnatal age. STUDY DESIGN Prospective study. SUBJECTS Forty preterm infants were assessed from the post-conceptional age (PCA) of 34 weeks. Two groups were made up according to postnatal age (PNA): low PNA (PNA≤10 days of life) and high PNA (PNA≥12 days of life). OUTCOME MEASURES An object (prism or cylinder) was presented repeatedly in the left hand, and holding times of the object were recorded during each trial. RESULTS Holding time was shorter for all preterm infants following successive presentation of the same object irrespective of postnatal age range. In the discrimination phase, the mean holding time for the novel object was longer than holding times in the last two habituation trials, in both PNA groups. Finally, the mean holding time of the familiar object presented in the recognition phase was shorter than the holding time of the novel object presented previously, but only in the low PNA group. CONCLUSIONS Tactile manual habituation and discrimination of shape information is present in preterm infants at a post-conceptional age of 34 weeks, independently of postnatal age. However, tactile manual recognition of familiar shapes following interference is affected by length of postnatal experience. The significance of this last result is discussed in detail.

Intermanual transfer of shapes in preterm human infants from 33 to 34 + 6 weeks postconceptional age.

This study investigated the ability of preterm infants to learn an object shape with one hand and discriminate a new shape in the opposite hand (without visual control). Twenty-four preterm infants between 33 and 34 + 6 gestational weeks received a tactile habituation task with either their right or left hand followed by a tactile discrimination task in the opposite hand. The results confirmed that habituation occurred for both shapes and both hands. Infants subsequently held the novel shape longer in the opposite hand. The results reveal that preterm infants are capable of intermanual transfer of shape information. In spite of the immaturity of the corpus callosum in preterm infants, its development seems to be sufficient to allow some transfer of information between both hands.

Altered Amygdala Development and Fear Processing in Prematurely Born Infants

Context: Prematurely born children have a high risk of developmental and behavioral disabilities. Cerebral abnormalities at term age have been clearly linked with later behavior alterations, but existing studies did not focus on the amygdala. Moreover, studies of early amygdala development after premature birth in humans are scarce. Objective: To compare amygdala volumes in very preterm infants at term equivalent age (TEA) and term born infants, and to relate premature infants’ amygdala volumes with their performance on the Laboratory Temperament Assessment Battery (Lab-TAB) fear episode at 12 months. Participants: Eighty one infants born between 2008 and 2014 at the University Hospitals of Geneva and Lausanne, taking part in longitudinal and functional imaging studies, who had undergone a magnetic resonance imaging (MRI) scan at TEA enabling manual amygdala delineation. Outcomes: Amygdala volumes assessed by manual segmentation of MRI scans; volumes of cortical and subcortical gray matter, white matter and cerebrospinal fluid (CSF) automatically segmented in 66 infants; scores for the Lab-TAB fear episode for 42 premature infants at 12 months. Results: Amygdala volumes were smaller in preterm infants at TEA than term infants (mean difference 138.03 mm3, p < 0.001), and overall right amygdala volumes were larger than left amygdala volumes (mean difference 36.88 mm3, p < 0.001). White matter volumes were significantly smaller (p < 0.001) and CSF volumes significantly larger (p < 0.001) in preterm than in term born infants, while cortical and subcortical gray matter volumes were not significantly different between groups. Amygdala volumes showed significant correlation with the intensity of the escape response to a fearsome toy (rs = 0.38, p = 0.013), and were larger in infants showing an escape response compared to the infants showing no escape response (mean difference 120.97 mm3, p = 0.005). Amygdala volumes were not significantly correlated with the intensity of facial fear, distress vocalizations, bodily fear and positive motor activity in the fear episode. Conclusion: Our results indicate that premature birth is associated with a reduction in amygdala volumes and white matter volumes at TEA, suggesting that altered amygdala development might be linked to alterations in white matter connectivity reported in premature infants. Moreover, our data suggests that such alterations might affect infants’ fear-processing capabilities.

The integration of visual context information in facial emotion recognition in 5- to 15-year-olds

The current study investigated the role of congruent visual context information in the recognition of facial emotional expression in 190 participants from 5 to 15years of age. Children performed a matching task that presented pictures with different facial emotional expressions (anger, disgust, happiness, fear, and sadness) in two conditions: with and without a visual context. The results showed that emotions presented with visual context information were recognized more accurately than those presented in the absence of visual context. The context effect remained steady with age but varied according to the emotion presented and the gender of participants. The findings demonstrated for the first time that children from the age of 5years are able to integrate facial expression and visual context information, and this integration improves facial emotion recognition.

Le toucher chez les enfants prématurés

Touch being the first sense to develop in utero, it plays an essential role in the perceptual-cognitive development in infancy. The study of tactile skills in premature infants is a relevant approach to better understand the early development of touch. After briefly summarizing some elements of neurophysiological substrates of passive and active touch, namely the somatosensory system and its early development, this article describes, first, a review of experimental work on early skills of premature infants in both passive touch and active touch, and secondly, a summary of studies about two programs of developmental care in which touch is an essential component: the massage therapy and the kangaroo mother care. Overall, studies show in premature infants the occurrence of 1. discrimination subsequent to passive tactile stimulation from 30 weeks of gestation; 2. active manual discrimination between two different object shapes from 28 weeks and finally 3. beneficial effects on their neurodevelopmental future after receiving a massage therapy or the kangaroo mother care.

Développement des fonctions exécutives de l’enfant prématuré

The rate of children born prematurely has increased considerably in the last few decades, and their developmental outcome remains of great concern. The literature on the impact of prematurity has reported a wide range of cognitive and behavioral problems that may be related to deficits in executive function (EF) skills. EF refers to a series of high-level processes (selective attention, inhibition, set shifting, working memory, planning, goal setting) that develop throughout childhood and adolescence and play an important role in cognitive and social development as well as in school achievement. EF skills have been linked to the prefrontal cortex, as well as to other neural networks and brain regions including the basal ganglia and cerebellum. This paper focuses on studies related to the development of EF and social behavior in children born preterm. The preschool period is a critical time to perform neuropsychological assessment in addition to IQ testing, and to detect the childs specific needs in order to adapt effective intervention to enhance the development of executive processes in these high-risk children.