Early indications of delayed cognitive development in preschool children born very preterm: evidence from domain‐general and domain‐specific tasks

Cognitive impairment often follows preterm birth but its early underlying nature is not well understood. We used a novel approach by investigating the development of colour cognition in 54 very preterm children born ?30 weeks gestational age without severe neurosensory impairment and 37 age‐matched term‐born controls, aged 2–5 years. Quantitative and qualitative differences in the development of colour cognition are well charted throughout the preschool years, enabling delayed from deviant development to be determined. Standardized domain‐general and experimental colour‐specific tests of language, attention, and memory were employed. Very preterm children showed significantly depressed language than term controls, with very preterm group girls significantly outperforming boys. Very preterm children also showed poorer attention and memory than term controls, but not significantly so. Importantly, colour‐specific tests showed qualitatively similar performance, but for naming and executive planning quantitatively poorer performance, across groups, indicating typical but delayed development. Hence, even before school entry, compared with term‐born peers, very preterm children show delayed development of cognitive processes that underpin later scholastic abilities, but the nature by which these processes operate appears to be typical of term children. If left untreated these early developmental delays may underpin later deviations from the typical developmental trajectory. Copyright © 2010 John Wiley & Sons, Ltd.     

Ophthalmological,cognitive, electrophysiological and MRI assessment of visual processing in preterm children without major neuromotor impairment

Many studies report chronic deficits in visual processing in children born preterm. We investigated whether functional abnormalities in visual processing exist in children born preterm but without major neuromotor impairment (i.e. cerebral palsy). Twelve such children (< 33 weeks gestation or birthweight < 1000 g) without major neuromotor impairment and 12 born full‐term controls were assessed at 8–12 years of age by means of ophthalmological assessment (visual acuity, colour vision, stereopsis, stereoacuity, visual fields, ocular motility, motor fusion), cognitive tests of visual‐motor, visual‐perceptual and visual‐spatial skills and pattern‐reversal visual evoked potentials (PR‐VEPs). All participants also underwent magnetic resonance imaging (MRI) of the brain and neuromotor assessments. No significant differences were found between the groups on the ophthalmological, visual cognitive, neurological, neuromotor or MRI measures. The P100 component of the PR‐VEP showed a significantly shorter latency in the preterm compared with the full‐term participants. Whilst this P100 finding suggests that subtle abnormalities may exist at the neurophysiological level, we conclude that visual dysfunction is not systematically associated with preterm birth in the context of normal neurological status.     

Executive Functions in Preschool Children Born Preterm: Application of Cognitive Neuroscience Paradigms

Although children born preterm are at risk for neuropsychological impairments at school age and adolescence, including difficulties with visual motor integration, spatial/constructional skills, attention, arithmetic, and nonverbal executive functions, specific neuropsychological outcome has not been investigated adequately in preschoolers. Application of cognitive neuroscience tasks offers the opportunity to characterize early executive functions in young children born preterm. In a preliminary sample of 29 preschool children born preterm (M birth gestational age = 32.4 weeks), executive function outcome was compared to that of fullterm controls by contrasting performance on two prototypic delayed-response-type paradigms, Delayed Alternation and Spatial Reversal. Preschoolers born preterm correctly retrieved the reward on fewer trials on Delayed Alternation than did matched controls. Furthermore, preschool children born preterm used problem-solving strategies that included more perseverative errors than controls. These preliminary findings highlight the utility of cognitive neuroscience paradigms to understand neuropsychological outcome in preschool children born preterm and suggest areas of developmental vulnerability that may include dorsolateral prefrontal circuits.     

Executive functions in preschool children born preterm: application of cognitive neuroscience paradigms.

Although children born preterm are at risk for neuropsychological impairments at school age and adolescence, including difficulties with visual motor integration, spatial/constructional skills, attention, arithmetic, and nonverbal executive functions, specific neuropsychological outcome has not been investigated adequately in preschoolers. Application of cognitive neuroscience tasks offers the opportunity to characterize early executive functions in young children born preterm. In a preliminary sample of 29 preschool children born preterm (M birth gestational age = 32.4 weeks), executive function outcome was compared to that of fullterm controls by contrasting performance on two prototypic delayed-response-type paradigms, Delayed Alternation and Spatial Reversal. Preschoolers born preterm correctly retrieved the reward on fewer trials on Delayed Alternation than did matched controls. Furthermore, preschool children born preterm used problem-solving strategies that included more perseverative errors than controls. These preliminary findings highlight the utility of cognitive neuroscience paradigms to understand neuropsychological outcome in preschool children born preterm and suggest areas of developmental vulnerability that may include dorsolateral prefrontal circuits.     

Visual‐motor and executive functions in children born preterm: The Bender Visual Motor Gestalt Test revisited

Böhm, B., Lundequist, A. & Smedler, A.‐C. (2010). Visual‐motor and executive functions in children born preterm: The Bender Visual Motor Gestalt Test revisited. Scandinavian Journal of Psychology, 51, 376–384. Visual‐motor development and executive functions were investigated with the Bender Test at age 5½ years in 175 children born preterm and 125 full‐term controls, within the longitudinal Stockholm Neonatal Project. Assessment also included WPPSI‐R and NEPSY neuropsychological battery for ages 4–7 ( Korkman, 1990 ). Bender protocols were scored according to Brannigan & Decker (2003) , Koppitz (1963) and a complementary neuropsychological scoring system (ABC), aimed at executive functions and developed for this study. Bender results by all three scoring systems were strongly related to overall cognitive level (Performance IQ), in both groups. The preterm group displayed inferior visual‐motor skills compared to controls also when controlling for IQ. The largest group differences were found on the ABC scoring, which shared unique variance with NEPSY tests of executive function. Multiple regression analyses showed that hyperactive behavior and inattention increased the risk for visual‐motor deficits in children born preterm, whereas no added risk was seen among hyperactive term children. Gender differences favoring girls were strongest within the preterm group, presumably reflecting the specific vulnerability of preterm boys. The results indicate that preterm children develop a different neurobehavioral organization from children born at term, and that the Bender test with a neuropsychological scoring is a useful tool in developmental screening around school start.     

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.     

Cognitive predictors of parent-rated inattention in very preterm children: The role of working memory and processing speed

Inattention is one of the most common neurobehavioral problems following very preterm birth. Attention problems can persist into adulthood and are associated with negative socio-emotional and educational outcomes. This study aimed to determine whether the cognitive processes associated with inattention differ between term-born and very preterm children. Sixty-five children born very preterm (<33+0 weeks’ gestation) aged 8–11 years were recruited alongside 48 term-born controls (?37 20 +0 weeks’ gestation). Both groups included children with a wide spectrum of parent-rated inattention (above average attention to severe inattention) measured as a continuous dimension using the Strengths and Weaknesses of ADHD and Normal-Behavior (SWAN) scale. The children completed tests to assess basic cognitive processes and executive function. A hierarchical multiple regression analysis was implemented to assess which neurocognitive processes explained variance in parent-rated inattention and whether these differed between preterm and term-born children. In both groups, poorer verbal and visuospatial short-term memory and poorer visuospatial working memory independently explained variance in parent-rated inattention. Slower motor processing speed explained variance in inattention among very preterm children only. The cognitive mechanisms associated with parent-rated inattention were predominantly overlapping between groups, but relationships between motor processing speed and inattention were unique to very preterm children. These associations may reflect risk factors for inattention in term and very preterm children. Future research should assess the efficacy of these cognitive processes as potential targets for intervention     

The impact of periventricular brain injury on reading and spelling abilities in the late elementary and adolescent years.

The present study was designed: (1) to investigate the long-term consequences of both the presence and the severity of periventricular brain injury (PVBI) on intellectual, academic, and cognitive outcome in extremely-low-birthweight (ELBW: < 1,000 grams) children at a mean age of 11 years; and (2) to determine the nature of the underlying difficulties associated with academic problems in these children. The results indicated that ELBW children without PVBI performed as well as full-term children on intelligence, academic, and cognitive ability tests. In contrast, ELBW children with mild and severe PVBI achieved significantly lower scores than either ELBW children without PVBI or children who were born at term. A second analysis indicated that, after accounting for Full Scale IQ, working memory and phonological processing were significant predictors of reading and spelling performance in ELBW children. These findings suggest that the presence and severity of PVBI, and not ELBW status alone, is associated with performance on tests of intelligence, and academic and cognitive functioning, and that some of the same factors known to be associated with learning disabilities in full-term children contribute to learning disabilities in ELBW children.     

Predicting preschool motor and cognitive performance in appropriate-for-gestational-age children born at ≤ 32 weeks gestation

Although many follow-up studies have been performed on preterm infants, little attention has been devoted to prediction of motor skills in the preschool or school years. We studied the relationship of performance on the Bayley Scales of Infant Development at a mean corrected age of 21 months to performance on the McCarthy Scales of Children's Abilities at a mean corrected age of 44.7 months for 43 appropriate-for-gestational-age (AGA) children born at ≤ 32 weeks gestation. Motor scores were stable over time with a significant correlation between the Bayley Psychomotor Developmental Index (PDI) and the McCarthy Motor subscale (r = 0.60; p = 0.0001). Scores of cognitive abilities also showed a significant correlation between the Bayley Mental Developmental Index (MDI) and the McCarthy General Cognitive Index (r = 0.42; p = 0.009). Small-for-gestational-age (SGA), very low-birthweight (≤ 1500 grams) children scored lower on the McCarthy General Cognitive Index (p = 0.01) and on the Motor subscale (p = 0.047) than the AGA children. We concluded that motor performance of AGA children born at ≤ 32 weeks gestation is stable from toddlerhood to preschool age. We suggest that SGA children be excluded from studies of motor performance of prematurely born children.     

Patterns of motor disability in very preterm children

Motor development in very preterm children differs in several important ways from that of children born at full term. Variability is common, although the anatomic and physiologic bases for that variability are often poorly understood. Motor patterns over the first postnatal year may depend on behaviours learned during often long periods of neonatal intensive care. The normal pattern of development may be modified by disturbances of brain function caused both by the interruption of normal brain maturation ex-utero and the superimposition of focal brain injuries following very preterm birth. Abnormal patterns of development over the first year may evolve into clear neuromotor patterns of cerebral palsy or resolve, as "transient dystonias." Cerebral palsy is associated with identified patterns of brain injury secondary to ischaemic or haemorrhagic lesions, perhaps modified by activation of inflammatory cytokines. Cerebral palsy rates have not fallen as might be expected over the past 10 years as survival has improved, perhaps because of increasing survival at low gestations, which is associated with the highest prevalence of cerebral palsy. Children who escape cerebral palsy are also at risk of motor impairments during the school years. The relationship of these impairments to perinatal factors or to neurological progress over the first postnatal year is debated. Neuromotor abnormalities are the most frequent of the "hidden disabilities" among ex-preterm children and are thus frequently associated with poorer cognitive ability and attention deficit disorders. Interventions to prevent cerebral palsy or to reduce these late disabilities in very preterm children are needed.     

Stability of developmental status and risk of impairment at 24 and 36 months in late preterm infants

BackgroundFew studies investigated whether late preterm infants might have developmental delays in several domains in early life and how stable the lag in developmental status might be.AimWe aimed to examine the stability of potential delays across developmental domains at 24 and 36 months of age in late preterm (34°-36⁶ weeks) and term (≥37 weeks) children and whether the risk of delays remained high at 36 months.Study design, subjects, and outcome measureWe conducted a prospective cohort analysis of the children of pregnant women participating in the Vitamin Antenatal Asthma Reduction Trial (VDAART). 652 children who were prospectively followed up and had parent-completed Ages Stages Questionnaires (ASQ-3) questionnaires at both 24 and 36 months were analyzed to assess their domain-specific developmental status.Results6.61 % (42/635) of children had a late preterm birth. Developmental delays were stable between 24 and 36 months on all 5 domains for the children born preterm and on 4/5 domains for those born at term. The developmental domains with the status stability at 24 and 36 months in both late preterm and term children were the gross motor, communication, personal-social skills, and problem-solving. Late preterm children compared with term children remained at higher risk of delays at 36 months for gross motor, communication, and problem-solving skills (aOR = 4.54, 95 %CI: 1.81−10.79; aOR = 8.60, 95 %CI: 3.10−23.28 and aOR = 3.80, 95 %CI: 1.58−8.73, respectively).ConclusionLate preterm birth is associated with suboptimal development and stability in several domains at both 24 and 36 months and compared with term birth, requiring early monitoring and assessment of the developmental lag to avoid potential long-term implications.     

The influence of motor function on processing speed in preterm and term-born children

This study investigates the relationship between motor function and processing speed in preterm children. Processing speed was compared in 145 adolescents, born 25–41 weeks gestational age, utilizing tasks including differing motor demands. The influence of motor cortex excitability and functional motor skills on task performance was assessed. For tasks with motoric demands, differences in performance between preterm and term-born children were mediated by the relationship between gestational age, corticomotor excitability, and motor function. There were no differences in non-motor processing speed task performance between preterm and term-born children. Measures of processing speed may be confounded by a timed motor component.     

The Impact of Periventricular Brain Injury on Reading and Spelling Abilities in the Late Elementary and Adolescent Years

The present study was designed: (1) to investigate the long-term consequences of both the presence and the severity of periventricular brain injury (PVBI) on intellectual, academic, and cognitive outcome in extremely-low-birthweight (ELBW: < 1,000 grams) children at a mean age of 11 years; and (2) to determine the nature of the underlying difficulties associated with academic problems in these children. The results indicated that ELBW children without PVBI performed as well as full-term children on intelligence, academic, and cognitive ability tests. In contrast, ELBW children with mild and severe PVBI achieved significantly lower scores than either ELBW children without PVBI or children who were born at term. A second analysis indicated that, after accounting for Full Scale IQ, working memory and phonological processing were significant predictors of reading and spelling performance in ELBW children. These findings suggest that the presence and severity of PVBI, and not ELBW status alone, is associated with performance on tests of intelligence, and academic and cognitive functioning, and that some of the same factors known to be associated with learning disabilities in full-term children contribute to learning disabilities in ELBW children.     

Social skills and nonverbal decoding of emotions in very preterm children at early school age

The aim of this study was to investigate the nonverbal decoding of emotion in a group of very preterm children and its relationship to social skills and problem behaviours. All children born less than 30 weeks gestation were prospectively enrolled in developmental follow-up. At 8 years of age, 112 children were assessed using the Receptive Faces subtest of the Diagnostic Analysis of Nonverbal Accuracy. Parents and teachers were asked to complete the Social Skills Rating System. In this very preterm group, 12.5% were rated by their parents as having a social skills impairment. Children were dichotomized by median split into below and above-average social skills groups. These groups differed significantly for social skill acquisition deficits, but not for the performance of already acquired skills. Children with below-average social skills showed significantly more errors in decoding emotional stimuli for both adult and child faces. Anger and low-intensity stimuli were particularly problematic. Ratings for behaviour problems were not related to decoding ability. Among social skills, assertion and responsibility were significantly related to decoding skills of child faces. The ability to decode facial emotion appears to be a factor in poorer social skills performance in very preterm children.     

Selective deficit in spatial location memory in extremely low birth weight children at age six: The PETIT Study

Spatial location memory has rarely been assessed in young children due to a scarcity of developmentally appropriate tests. This study sought to compare nonverbal learning and recall in children born extremely low birth weight (ELBW; <1000 g) and less than 33 gestational weeks (GW) with term-born children at early school age using a recently developed and adapted test. We administered a modification of the Hopkins Board to 210 children at age six; 84 born ELBW (35 born < 26 GW; 49 born 26–33 GW) and 126 term-born. Six measures were obtained: naming, trials-to-criterion, errors-to-criterion, delayed item recall, delayed location recall, and percent retention. After age correction, ELBW children had worse general cognition, item naming, delayed item recall, delayed location recall, and percent retention than term-born children. Delayed item recall and percent retention performances of ELBW children remained worse after correction for general cognition. ELBW groups (< 26 GW and 26–33 GW) groups performed worse than term-born children in naming and delayed item recall with chronological age as covariate. Those born before 26 GW, but not 26–33 GW, performed worse than term-born children in delayed location recall and percent retention. Differences remained significant after controlling for gender, maternal education, and delivery type. All three groups' performance declined from final learning trial to delayed location recall, with a decline greater for less than 26 GW than term-born children. Extreme prematurity (< 26 GW) and ELBW are significant risk factors for spatial location memory deficit. The modified Hopkins Board discriminated high-risk preterm and term-born children at early school age and appears to be a useful test to measure this rarely studied cognitive capacity.     

Investigating socio-emotional cognition in late preterm children: A case-control study

ABSTRACT

This study aimed to investigate socio-emotional cognitive competence in late preterm and term born children. Late preterm children (n = 53; 5–10 years) and full-term control children (n = 53; 5–10 years) were evaluated on the four socio-emotional cognitive tests of the Intelligence and Development Scales (IDS): emotion recognition, emotion regulation, social understanding, and social behavioural competence. Compared to full-term children, late preterm children (LPT) performed significantly worse on the emotion recognition and social behavioural competence tasks, but otherwise, no significant differences were found in emotion regulation and social understanding tasks. These findings support the conclusion that late-preterm birth may be associated with negative, but selective, socio-emotional cognitive difficulties. Targeted interventions aimed to limit the incidence of these dysfunctions during childhood could be quite important for LPT children.     

Cognitive development in 7- to 24-month-old extremely/very-to-moderately/late preterm and full-term born infants: The mediating role of focused attention

The present study analyzed the links between prematurity, attention, and global cognitive performance in infancy and early childhood. At 7 months, focused attention (FA) was examined with an object examination task in 93 preterm infants (39 of them born extremely/very preterm, 54 born moderately/late preterm, and 38 infants born full-term). Global cognition was assessed at 7 and 24 months with the Bayley-II cognitive scale. Groups did not differ with respect to global cognitive performance but FA of infants born extremely/very preterm was significantly lower than in infants born moderately/late preterm. FA correlated significantly with both prematurity and cognitive performance at 7 months of age but not with global cognition in childhood. Findings point to a subtle adverse effect of prematurity on early attention and reveal evidence for the mediating role of FA on the effect of prematurity on cognition.     

Mathematics ability and related skills in preschoolers born very preterm

Children born very preterm (VPT) are at risk for academic, behavioral, and/or emotional problems. Mathematics is a particular weakness and better understanding of the relationship between preterm birth and early mathematics ability is needed, particularly as early as possible to aid in early intervention. Preschoolers born VPT (n = 58) and those born full term (FT; n = 29) were administered a large battery of measures within 6 months of beginning kindergarten. A multiple-mediation model was utilized to characterize the difference in skills underlying mathematics ability between groups. Children born VPT performed significantly worse than FT-born children on a measure of mathematics ability as well as full-scale IQ, verbal skills, visual–motor integration, phonological awareness, phonological working memory, motor skills, and executive functioning. Mathematics was significantly correlated with verbal skills, visual–motor integration, phonological processing, and motor skills across both groups. When entered into the mediation model, verbal skills, visual–motor integration, and phonological awareness were significant mediators of the group differences. This analysis provides insights into the pre-academic skills that are weak in preschoolers born VPT and their relationship to mathematics. It is important to identify children who will have difficulties as early as possible, particularly for VPT children who are at higher risk for academic difficulties. Therefore, this model may be used in evaluating VPT children for emerging difficulties as well as an indicator that if other weaknesses are found, an assessment of mathematics should be conducted.     

Attention development in infants and preschool children born preterm: a review

A potential mechanism that can explain preterm children's heightened risk for the development of later cognitive and behavioral problems is attention. Attention is the ability of an infant or child to orient to, to shift between and to maintain focus on events, objects, tasks, and problems in the external world, processes which are all dependent on the functioning of attentional networks in the brain. The aim of this paper is to provide a review of the literature on attention development in children born preterm during the first 4 years of life. First, research examining the differences between preterm and full-term children indicates that early attention development in infants born preterm is less optimal and that these differences increase when infants grow into toddlers. Second, studies investigating individual differences within preterm populations reveal the influence of both biological factors and environmental factors. Third, individual differences in early orienting and sustained attention have been shown to be predictive of later attentional, cognitive and behavioral functioning in children born preterm. The importance of long-term follow-up studies, with a focus on individual developmental trajectories in orienting, sustained and executive attention, is emphasized.     

Attention Deficits in Children with &lt; 750 gm Birth Weight

Although attention deficit disorders are frequently diagnosed in low birth-weight children, it is not clear if attention problems are apparent in neuropsychological testing. The present study examined the performances of a regional sample of 68 children with birth weights &lt;750 gm on several psychometric measures of attention given at early school age. Matched groups of 65 children with birth weights between 750–1499 gm and 61 term controls were also assessed. The group &lt;750 gm performed more poorly on one attention test than did either comparison group, even when overall cognitive ability was taken into account. Performances on the attention tests were also related to academic skills and ratings of behavior. Findings confirm the hypothesis that children with birth weights &lt;750 gm have specific attentional weaknesses and support the validity of attention tests as predictors of learning and behavior problems.