Cranial ultrasound findings in late preterm infants and correlation with perinatal risk factors.

BACKGROUND: Late preterm infants are the most represented premature babies. They are exposed to a wide spectrum of brain lesions which are often clinically silent, supporting a possible role of cerebral ultrasound screening. Aim of the study is to describe the pattern of cranial ultrasound abnormalities in late preterm infants and to define the need for cranial ultrasound according to perinatal risk factors. METHODS: A hospital-based cranial ultrasound screening was carried out by performing two scans (at 1 and 5 weeks). Unfavorable cranial ultrasound at 5 weeks was defined as either persistent periventricular hyperechogenicity or severe abnormalities. RESULTS: One thousand one hundred seventy-two infants were included. Periventricular hyperechogenicity and severe abnormalities were observed in, respectively, 19.6 % and 1 % of late preterms at birth versus 1.8 % and 1.4 % at 5 weeks. Periventricular hyperechogenicity resolved in 91.3 %. At the univariate analysis gestational age (OR 0.5, 95 % CI 0.32-0.77), Apgar score <5 at 5' (OR 15.3, 1.35-173) and comorbidities (OR 4.62, 2.39-8.98) predicted unfavorable ultrasound at 5 weeks. At the multivariate analysis the accuracy in predicting unfavorable ultrasound, estimated by combined gestational age/Apgar/comorbidities ROC curve, was fair (AUC 74.6) and increased to excellent (AUC 89.4) when ultrasound at birth was included. CONCLUSION: Gestational age and comorbitidies are the most important risk factors for detecting brain lesions. The combination of being born at 34 weeks and developing RDS represents the strongest indication to perform a cranial ultrasound. Differently from other studies, twin pregnancy doesn't represent a risk factor.

Emerging executive skills in very preterm children at 2 years corrected age: a composite assessment.

Executive Function (EF) deficits have previously been identified in preterm children. However, only recently have emerging executive functions been studied in preschool children who were born preterm without major brain damage. Our study provides a broad assessment of EFs in 72 extremely preterm births (gestational age < 34 weeks and birth weight < 2500 g) and 73 full-term children, born between 2006 and 2008, at 24 months of corrected age. Three factors were extracted from the EF administered measures: working memory, cognitive flexibility, and impulsivity control. Only cognitive flexibility was found to discriminate preterm children from controls.

Perceptual-motor abilities in pre-school preterm children.

BACKGROUND: Several studies report a high percentage of premature infants presenting perceptual motor difficulties at school age. The new version of the Movement Assessment Battery for Children allows the assessment of perceptual-motor abilities in children from the age of 3years. AIMS: To evaluate early perceptual-motor abilities in prematurely born children below the age of 4years. STUDY DESIGN: The Movement Assessment Battery for Children 2nd edition was administered to 105 low-risk prematurely born children (<32weeks gestation) and in a control group of 105 term-born children matched for age and sex. All children were assessed between the age of 3years and 3years-11months. RESULTS: 63 children (60%) had total scores above the 15th percentile, 15 (14.3%) had scores between the 5th and the 15th percentile, and 13 (12.4%) below the 5th percentile. The remaining 14 children (13.3%) refused to perform or to complete the test. The difference between preterm and control group was significant for total scores, Manual Dexterity and Aiming and Catching scores. In the preterm group there was a correlation between age at testing, total scores and Aiming and Catching subscores. The Movement ABC-2 subscores were significantly lower in children born below 29weeks. CONCLUSION: Perceptual-motor difficulties can already be detected on the assessment performed before the age of 4years. Prematurely born children assessed between 3years and 3years-3months appeared to have more difficulties in performing the test than the older ones or their age matched term-born peers. These findings support the possibility of a delayed maturation in the younger age group.

Early visual assessment in preterm infants with and without brain lesions: correlation with visual and neurodevelopmental outcome at 12 months.

BACKGROUND: Several studies have reported the development of various aspects of visual function in infancy and early childhood in both preterm and term-born infants, but only a few studies have focused on the predictive power of neonatal visual findings in infants with brain lesions. AIMS: To explore visual findings at term age, and at 3 and 12 months corrected age in preterm infants (gestational age <33 weeks) with and without brain lesions; to compare the assessment at term age and at 12 months; and to assess the relationship between visual findings and neurodevelopmental outcome at 12 months. STUDY DESIGN: Cranial ultrasound scans (US) were classified in normal, mild or major abnormalities. One-hundred and forty-five infants were assessed with age specific tests for visual function at term age, and at 3 and 12 months. Neurodevelopmental assessment (Griffiths' Scales) was performed at 12 months. RESULTS: A good correlation was found between early and late visual assessment and neurodevelopment outcome. Of the 121 infants with normal neonatal visual assessment, 119 were also normal at 12 months and 116 had normal developmental quotient. Of the 24 infants with abnormal neonatal visual assessment, 12 were also abnormal at 12 months. All the false positives had normalised by 3 months. Of the 35 infants with major US abnormalities, 20 had normal and 15 abnormal scores on the neonatal assessment. At 1 year 17 had normal and 18 abnormal scores. CONCLUSION: A normal visual assessment at term age is a good predictor of normal visual and neurodevelopmental outcome at 12 months. An abnormal visual examination in the neonatal period was a less reliable prognostic indicator, infant should be reassessed at 3 months.

Visual performance and brain structures in the developing brain of pre-term infants.

The presence of abnormal visual function has been related to overt lesions in the thalami, peritrigonal white matter (such as cavitational-necrotic periventricular leucomalacia) and optic radiations, and also to the extent of occipital cortex involvement. The normal development of visual function seems to depend on the integrity of a network that includes not only optic radiations and the primary visual cortex but also other cortical and subcortical areas, such as the frontal or temporal lobes or basal ganglia, which have been found to play a topical role in the development of vision. Therefore, the complex functions and functional connectivity of the developing brain of premature infants can be studied only with highly sophisticated techniques such as diffusion tensor tractography. The combined use of visual tests and neonatal structural and functional neuroimaging, which have become available for newborn infants, provides a better understanding of the correlation between structure and function from early life. This appears to be particularly relevant considering the essential role of early visual function in cognitive development. The identification of early visual impairment is also important, as it allows for early enrolment in intervention programmes. The association of clinical and functional studies to newer imaging techniques, which are being increasingly used also in neonates, are likely to provide further information on early aspects of vision and the mechanisms underlying brain plasticity, which are still not fully understood. Early exposure to a difficult postnatal environment together with early and unexpected removal from a protective milieu are exclusive and peculiar factors of prematurity that interfere with the normal development of the visual system in pre-term babies. The problem is further compounded by the influence of different perinatal brain lesions affecting the developing brain of premature babies. Nevertheless, in the last few decades, there have been considerable advances in our understanding of the development of vision in pre-term infants during early infancy. This has mainly been due to the development of age-specific tests assessing various aspects of visual function, from ophthalmological examination to more cortical aspects of vision, such as the ability to process orientation or different aspects of visual attention [1-7]. Improvements in understanding very early and specific neurological impairments in neurological functions have been reported in pre-term infants, known to be at risk of developing visual and visual-perceptual impairment. These impairments are due not only to retinopathy, a common finding in premature infants, but also to cerebral (central) visual impairment, secondary to brain lesions affecting the central visual pathway.