Influence of swaddling on tactile manual learning in preterm infants.

BACKGROUND AND AIM: Swaddling is a well-known technique in developmental care programs as there is some evidence that swaddling is an appropriate stress-reducing method for preterm infants in the NICU. However, no experimental study has investigated the influence of swaddling in a learning context. This study aimed to assess the impact of swaddling on tactile manual abilities in preterm infants. METHODS: Two phases were introduced for all infants: habituation (successive presentation of the same object, prism or cylinder in the left hand), followed by discrimination (presentation of a new-shaped object). The infants were assigned to one of the two conditions (swaddled; non-swaddled). RESULTS: Forty preterm infants were included (between 28 and 35 weeks' postconceptional age). First, swaddled and non-swaddled infants exhibited similar tactile habituation abilities. However, all infants needed more time and more trials to habituate to the cylinder than to the prism. Second, they all exhibited an effective discrimination, but the importance of the increase in holding time for the new-shaped object varied according to the habituated-shape and the condition. Moreover, stress intensity was higher in non-swaddled infants during tactile exploration. Finally, infants with greater previous swaddling experience during the week preceding the test took more time and more trials to habituate to the object, regardless of the condition. CONCLUSION: Swaddling preterm infants during sensory learning did not influence the tactile memorization process but would improve the use of their attentional resources. Swaddling seems to provide favorable conditions for sensory learning by improving attention to tactile stimuli. CLINICAL TRIAL REGISTRATION: This trial, EMMASENS, has been registered at www.clinicaltrials.gov (identifier NCT04315428).

Preterm infant showed better object handling skills in a neonatal intensive care unit during silence than with a recorded female voice.

AIM: This study compared whether preterm infants showed better tactile abilities during silence or when they heard a prerecorded female voice at different intensities. METHODS: We studied 74 preterm infants of 28-35 weeks' postconceptional age who were admitted to a French neonatal intensive care unit from 2014 to 2017. They were presented with wooden objects, one smooth and one angled, at various points during silence (n = 26) or while listening to a female voice at +5 (n = 24) or +15 decibels (n = 24) inside their incubator. We compared the conditions to see if there was any difference in how the infants handled the objects and also compared familiar and unfamiliar objects. RESULTS: The preterm infants showed better handling skills and only displayed effective discrimination, during silence. We found that 27.1% of the infants exposed to female voices failed to get habituated to the object, compared to 7.7% in the silence condition (p < 0.05) and success during the voice conditions required more trials (6.1 vs. 5.3) than the silence condition (p = 0.05). The different voice intensities made no difference. CONCLUSION: Being exposed to a female voice had a negative impact on preterm infants' tactile sensory learning, regardless of its intensity.

Sound levels in a neonatal intensive care unit significantly exceeded recommendations, especially inside incubators.

AIM: This study measured sound levels in a 2008 built French neonatal intensive care unit (NICU) and compared them to the 2007 American Academy of Pediatrics (AAP) recommendations. The ultimate aim was to identify factors that could influence noise levels. METHODS: The study measured sound in 17 single or double rooms in the NICU. Two dosimeters were installed in each room, one inside and one outside the incubators, and these conducted measurements over a 24-hour period. The noise metrics measured were the equivalent continuous sound level (Leq ), the maximum noise level (Lmax ) and the noise level exceeded for 10% of the measurement period (L10 ). RESULTS: The mean Leq , L10 and Lmax were 60.4, 62.1 and 89.1 decibels (dBA), which exceeded the recommended levels of 45, 50 and 65 dBA (p < 0.001), respectively. The Leq inside the incubator was significantly higher than in the room (+8 dBA, p < 0.001). None of the newborns' characteristics, the environment or medical care was correlated to an increased noise level, except for a postconceptional age below 32 weeks. CONCLUSION: The sound levels significantly exceeded the AAP recommendations, particularly inside incubators. A multipronged strategy is required to improve the sound environment and protect the neonates' sensory development.

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.

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.

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.

[Communicating with premature newborns through touch]. / Communiquer par le toucher avec le nouveau-né prématuré.

How does the premature newborn perceive the outside world? The first sense developed by the foetus is touch. Through the physiology of sensoriality and brain maturation, touch can constitute an essential vector in communicating with and caring for the premature child.