Formula: see text]Executive functions in extremely low birth weight and late-preterm preschoolers: Effects on working memory and response inhibition

Executive function (EF) refers to fundamental capacities that underlie more complex cognition and have ecological relevance across the individual's lifespan. However, emerging executive functions have rarely been studied in young preterm children (age 3) whose critical final stages of fetal development are interrupted by their early birth. We administered four novel touch-screen computerized measures of working memory and inhibition to 369 participants born between 2004 and 2006 (52 Extremely Low Birth Weight [ELBW]; 196 late preterm; 121 term-born). ELBW performed worse than term-born on simple and complex working memory and inhibition tasks and had the highest percentage of incomplete performance on a continuous performance test. The latter finding indicates developmental immaturity and the ELBW group's most at-risk preterm status. Additionally, late-preterm participants performed worse compared with term-born on measures of complex working memory but did not differ from those term-born on response inhibition measures. These results are consistent with a recent literature that identifies often subtle but detectable neurocognitive deficits in late-preterm children. Our results support the development and standardization of computerized touch-screen measures to assess EF subcomponent abilities during the formative preschool period. Such measures may be useful to monitor the developmental trajectory of critical executive function abilities in preterm children, and their use is necessary for timely recognition of deficit and application of appropriate interventional strategies.     

Executive functions in extremely low birth weight and late-preterm preschoolers: Effects on working memory and response inhibition

Executive function (EF) refers to fundamental capacities that underlie more complex cognition and have ecological relevance across the individual's lifespan. However, emerging executive functions have rarely been studied in young preterm children (age 3) whose critical final stages of fetal development are interrupted by their early birth. We administered four novel touch-screen computerized measures of working memory and inhibition to 369 participants born between 2004 and 2006 (52 Extremely Low Birth Weight [ELBW]; 196 late preterm; 121 term-born). ELBW performed worse than term-born on simple and complex working memory and inhibition tasks and had the highest percentage of incomplete performance on a continuous performance test. The latter finding indicates developmental immaturity and the ELBW group's most at-risk preterm status. Additionally, late-preterm participants performed worse compared with term-born on measures of complex working memory but did not differ from those term-born on response inhibition measures. These results are consistent with a recent literature that identifies often subtle but detectable neurocognitive deficits in late-preterm children. Our results support the development and standardization of computerized touch-screen measures to assess EF subcomponent abilities during the formative preschool period. Such measures may be useful to monitor the developmental trajectory of critical executive function abilities in preterm children, and their use is necessary for timely recognition of deficit and application of appropriate interventional strategies.     

Verbal Memory Deficits in Children with Less than 750 g Birth Weight

Numerous studies have documented memory deficits in very low birthweight (VLBW, < 1500 g) children, yet we know little about the nature of these memory problems. To clarify memory sequelae and examine memory deficits in relation to the degree of low birth weight, we administered the California Verbal Learning Test–Children’s Version (CVLT-C) to a regional sample of 57 < 750 g birthweight children and to groups of 53 750–1499 g birthweight children and 49 term-born controls. Group comparisons revealed significant differences between the < 750 g birthweight group and term-born children on measures of list learning, delayed recall, and inaccurate recall. In addition, the percentage improvement in correct recognitions relative to long-term delayed recall was greater in the < 750 g group than in the term-born controls. Similar differences were observed between VLBW children with and without abnormal neonatal cerebral ultrasounds (high- and low-risk groups). Differences in learning rate between the VLBW and term-born groups, and between high- and low-risk VLBW children, were evident even when vocabulary skill was covaried or when children with neurosensory deficits or IQ < 80 were excluded from analysis. The findings document deficits in verbal memory in the subset of VLBW children at greatest biological risk, and suggest that acquisition processes are selectively impaired.     

Developmental normative data for the Baron-Hopkins Board test of spatial location memory

Developmentally appropriate domain-specific tests with strong psychometric properties for preschoolers are lacking and infrequently developed. Baron’s modification of the Hopkins Board test (B-HB) to assess spatial location learning and recall in 3- and 6-year-old children has shown promise in the study of young children born prematurely. Current study data were analyzed on 172 typically developing children at age 3 years and 193 at age 6 years, born at term (≥ 37 weeks; ≥ 2500 grams). Statistically significant gender differences were found and data stratification of T-scores and percentile ranks are provided for each of the eight B-HB measures. The B-HB’s strong interrater reliability (99.5%), low-to-moderate test-retest reliability across the 3-year age span, Pearson correlations showing criterion validity, and differential functioning from other selective attention and visuospatial/visuoperceptual tests provide initial normative data for this novel measure of spatial location memory in young children.     

The contribution of visual processing to academic achievement in adolescents born extremely preterm or extremely low birth weight

Children born extremely preterm (EP, <28 weeks) and/or extremely low birth weight (ELBW, <1000 g) have more academic deficiencies than their term-born peers, which may be due to problems with visual processing. The aim of this study is to determine (1) if visual processing is related to poor academic outcomes in EP/ELBW adolescents, and (2) how much of the variance in academic achievement in EP/ELBW adolescents is explained by visual processing ability after controlling for perinatal risk factors and other known contributors to academic performance, particularly attention and working memory. A geographically determined cohort of 228 surviving EP/ELBW adolescents (mean age 17 years) was studied. The relationships between measures of visual processing (visual acuity, binocular stereopsis, eye convergence, and visual perception) and academic achievement were explored within the EP/ELBW group. Analyses were repeated controlling for perinatal and social risk, and measures of attention and working memory. It was found that visual acuity, convergence and visual perception are related to scores for academic achievement on univariable regression analyses. After controlling for potential confounds (perinatal and social risk, working memory and attention), visual acuity, convergence and visual perception remained associated with reading and math computation, but only convergence and visual perception are related to spelling. The additional variance explained by visual processing is up to 6.6% for reading, 2.7% for spelling, and 2.2% for math computation. None of the visual processing variables or visual motor integration are associated with handwriting on multivariable analysis. Working memory is generally a stronger predictor of reading, spelling, and math computation than visual processing. It was concluded that visual processing difficulties are significantly related to academic outcomes in EP/ELBW adolescents; therefore, specific attention should be paid to academic remediation strategies incorporating the management of working memory and visual processing in EP/ELBW children.     

Verbal memory deficits in children with less than 750 g birth weight.

Numerous studies have documented memory deficits in very low birthweight (VLBW, < 1500 g) children, yet we know little about the nature of these memory problems. To clarify memory sequelae and examine memory deficits in relation to the degree of low birth weight, we administered the California Verbal Learning Test-Children's Version (CVLT-C) to a regional sample of 57 < 750 g birthweight children and to groups of 53 750-1499 g birthweight children and 49 term-born controls. Group comparisons revealed significant differences between the < 750 g birthweight group and term-born children on measures of list learning, delayed recall, and inaccurate recall. In addition, the percentage improvement in correct recognitions relative to long-term delayed recall was greater in the < 750 g group than in the term-born controls. Similar differences were observed between VLBW children with and without abnormal neonatal cerebral ultrasounds (high- and low-risk groups). Differences in learning rate between the VLBW and term-born groups, and between high- and low-risk VLBW children, were evident even when vocabulary skill was covaried or when children with neurosensory deficits or IQ < 80 were excluded from analysis. The findings document deficits in verbal memory in the subset of VLBW children at greatest biological risk, and suggest that acquisition processes are selectively impaired.     

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.     

Visual configural processing in adults born at extremely low birth weight

Being born at extremely low birth weight (ELBW; ≤1,000 g) is associated with enduring visual impairments. We tested for long‐term, higher order visual processing problems in the oldest known prospectively followed cohort of ELBW survivors. Configural processing (spacing among features of an object) was examined in 62 adults born at ELBW (M_age = 31.9 years) and 82 adults born at normal birth weight (NBW; ≥2,500 g: M_age = 32.5 years). Pairs of human faces, monkey faces, or houses were presented in a delayed match‐to‐sample task, where non‐matching stimuli differed only in the spacing of their features. Discrimination accuracy for each stimulus type was compared between birth weight groups, adjusting for neurosensory impairment, visual acuity, binocular fusion ability, IQ, and sex. Both groups were better able to discriminate human faces than monkey faces (p < .001). However, the ELBW group discriminated between human faces (p < .001), between monkey faces (p < .001), and to some degree, between houses (p < .06), more poorly than NBW control participants, suggesting a general deficit in perceptual processing. Human face discrimination was related to performance IQ (PIQ) across groups, but especially among ELBW survivors. Coding (a PIQ subtest) also predicted human face discrimination in ELBW survivors, consistent with previously reported links between visuo‐perceptive difficulties and regional slowing of cortical activity in individuals born preterm. Correlations with Coding suggested ELBW survivors may have used a feature‐matching approach to processing human faces. Future studies could examine brain‐based anatomical and functional evidence for altered face processing, as well as the social and memory consequences of face‐processing deficits in ELBW survivors.     

Latent mean comparisons on the BRIEF in preterm children: Parent and teacher differences

Executive function is a heterogeneous construct applied to cognitive capacities that together enable individuals to effectively engage in activities toward a purposive goal. Children born at extremely low birth weight (ELBW) are at risk of executive dysfunction on performance-based measures. In natural contexts, executive function may be described using such parental and teacher questionnaires as the Behavior Rating Inventory of Executive Function (BRIEF). This study examined the factor structure of the BRIEF-parent form in 124 ELBW children and of the BRIEF-teacher form in 90 ELBW children. Although our data showed that the fit of a two-factor structure was adequate for the parent report, a three-factor model provided advantages over the two-factor model across all fit indices and best characterized the data. For teacher report, these data supported a three-factor but not a two-factor model. Using the three-factor model for both groups of informants, we compared parent and teacher reports (n = 90 pairs) between the three identified latent variables. Parents reported significantly more difficulty with Emotional Regulation (p < .05), and teachers reported significantly more difficulty with Behavioral Regulation (p < .05). No significant differences were found between parent and teacher reports for Metacognition.     

Still cautious: Personality characteristics of extremely low birth weight adults in their early 30s

Extremely low birth weight survivors (ELBW; <1000 g) display a personality style characterized by cautiousness, shyness, and risk aversion in their 20s. We examined whether non-impaired ELBW survivors were still more cautious than their normal birth weight (NBW) peers at ages 30–35 and assessed the stability of this personality characteristic across approximately a decade in the oldest known cohort of ELBW survivors. Of the 154 participants tested at ages 22–26, 111 (i.e., 72%) of them returned approximately 10 years later [i.e., 69% (49/71) ELBW and 75% (62/83) NBW], and once again they completed the Eysenck Personality Questionnaire-Revised (EPQ-R). We created the same theoretically and empirically derived composite measure of cautiousness at each visit by summing the EPQ-R psychoticism scale (reverse scored) and the EPQ-R lie scale. We found that ELBW adults reported higher cautiousness than their NBW counterparts at ages 30–35. We also found that levels of cautiousness remained stable over approximately 10 years in both groups. Our findings suggest that individuals born at ELBW were more cautious than NBW peers and that this personality characteristic remained stable into their early 30s. The present study appears to be the first empirical demonstration of personality stability among adult ELBW survivors.     

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.     

Relation between verbal recall and visual recognition of the same stimuli in young children

Five-year-old children (N = 112) were shown drawings of common objects three times either as a naming-and-learning task or as a preference task (incidental learning). A verbal recall test followed by a class- and item-recognition test, scaled to reflect the accuracy of item recognition, were given either 2 min or two weeks after presentation. Intentional learning with naming led to better immediate recall than incidental learning, but the recognition and delayed recall scores were equal for the two learning conditions. The probability of verbal recall of object names was in each case uncorrelated with the accuracy of visual recognition of the same objects by the same Ss. The results are closely similar to those obtained with adult Ss by Bahrick and Boucher (1968).     

The dissociation of repetition priming and recognition memory in language/learning-disabled children.

Recent research has found that the performance of learning-disabled and non-disabled children is dissociated on explicit and implicit tests of memory (Lorsbach & Worman, 1989). The current study further examined this phenomenon by comparing language/learning-disabled (L/LD) and nondisabled children (NLD) on tasks measuring primed picture-naming and item recognition. Included within the design of the experiment was the manipulation of both presentation format (pictures or words) and retention interval (immediate or 1 day). Children were initially presented with pictures and words. Performance was measured both immediately and following a 1-day retention interval on a picture naming task, an item recognition task, and a supplementary measure of memory for presentation format. The magnitude of facilitation associated with primed picture-naming was found to be independent of item recognition performance. In addition, the effects of population (L/LD and NLD) and retention interval (immediate test or 1 day) each produced dissociations between the magnitude of naming facilitation and item recognition performance. Results were discussed in terms of their implications for our understanding of the nature of memory difficulties in L/LD children.     

Test of visuospatial construction: Validity evidence in extremely low birth weight and late preterm children at early school age

The Test of Visuospatial Construction (TVSC), a measure of visuoconstruction that does not rely on upper extremity motor response or written production, was administered to extremely low birth weight (ELBW), late preterm (LPT), and term participants at preschool (n = 355) and kindergarten (n = 265) ages. TVSC showed statistically significant weak-to-moderate positive correlations (age 3: r = .118–.303; age 6: r = .138–.348) with Developmental VMI, Differential Ability Scales-II Copying, Matrices, and Pattern Construction subtests, Baron-Hopkins Board Test, and the Purdue Pegboard. One-way ANOVA indicated ELBW performed worse than Term (p = .044) on visuospatial construction at age 3 with a small-to-medium effect size (d = ?0.43). No other statistically significant differences were found at age 3 on the TVSC (ELBW/LPT: p = .608, d = ?0.17; LPT/Term: p = .116, d = ?0.31). At age 6, ELBW participants performed worse than LPT participants (p = .027) and Term participants (p = .012); LPT participants did not differ from Term participants. Small effect sizes at age 3 (ELBW < LPT, d = ?0.17; ELBW < Term, d = ?0.43) were notably larger at age 6 (ELBW < LPT, d = ?0.42; ELBW < Term, d = ?0.53). Important practical differences showing LPT participants performed below Term participants (d = ?0.31) at age 3 were no longer evident at age 6 (d = ?0.097). These findings provide preliminary evidence of TVSC validity supporting its use to detect neuropsychological impairment and to recommend appropriate interventions in young preterm children.     

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.     

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.     

Sources of Variability in Sequelae of Very Low Birth Weight

Few investigations have examined the specificity of sequelae of very low birth weight (VLBW, &lt;1500 g) or sources of variability in outcome. To better understand the nature and determinants of outcome, we assessed neuropsychological and achievement skills at mean age 11 years in 62 children with &lt;750 g birth weight, 54 with 750-1499 g birth weight, and 66 term-born controls. Distinct cognitive constructs were identified by factor analysis, and the three birthweight groups were compared on these constructs and on composite measures of achievement. Although the group with &lt;750 g birth weight performed less well on all tests than term-born controls, group differences in a perceptual planning factor and in mathematics remained even when IQ was controlled, and deficits were more pronounced in mathematics than in reading. Results from structural equation modeling were consistent with the hypothesis that neuropsychological skills mediated the relationship between birth weight and achievement. The findings confirm the differential deficit hypothesis, support the need to consider multiple sources of variability in VLBW outcomes, and highlight the importance of neuropsychological constructs in developing an explanatory framework.