Inhibitory control in children with agenesis of the corpus callosum compared with typically developing children.

OBJECTIVES: The developmental absence (agenesis) of the corpus callosum (AgCC) is a congenital brain malformation associated with risk for a range of neuropsychological difficulties. Inhibitory control outcomes, including interference control and response inhibition, in children with AgCC are unclear. This study examined interference control and response inhibition: 1) in children with AgCC compared with typically developing (TD) children, 2) in children with different anatomical features of AgCC (complete vs. partial, isolated vs. complex), and 3) associations with white matter volume and microstructure of the anterior (AC) and posterior commissures (PC) and any remnant corpus callosum (CC). METHODS: Participants were 27 children with AgCC and 32 TD children 8-16 years who completed inhibitory control assessments and brain MRI to define AgCC anatomical features and measure white matter volume and microstructure. RESULTS: The AgCC cohort had poorer performance and higher rates of below average performance on inhibitory control measures than TD children. Children with complex AgCC had poorer response inhibition performance than children with isolated AgCC. While not statistically significant, there were select medium to large effect sizes for better inhibitory control associated with greater volume and microstructure of the AC and PC, and with reduced volume and microstructure of the remnant CC in partial AgCC. CONCLUSIONS: This study provides evidence of inhibitory control difficulties in children with AgCC. While the sample was small, the study found preliminary evidence that the AC (f2=.18) and PC (f2=.30) may play a compensatory role for inhibitory control outcomes in the absence of the CC.

Episodic and prospective memory difficulties in 13-year-old children born very preterm.

OBJECTIVES: Children born very preterm (VP) are susceptible to a range of cognitive impairments, yet the effects of VP birth on long-term, episodic, and prospective memory remains unclear. This study examined episodic and prospective memory functioning in children born VP compared with their term-born counterparts at 13 years. METHOD: VP (n = 81: born <30 weeks' gestation) and term (n = 26) groups were aged between 12 and 14 years. Children completed: (i) standardized verbal and visuospatial episodic memory tests; and (ii) an experimental time- and event-based prospective memory test that included short-term (within assessment session) and long-term (up to 1-week post-session) tasks. Parents completed a questionnaire assessing memory functions in everyday life. RESULTS: The VP group performed worse on all measures of verbal and visuospatial episodic memory than the term group. While there were no group differences in event-based or long-term prospective memory, the VP group performed worse on time-based and short-term prospective memory tasks than term-born counterparts. Parents of children born VP reported more everyday memory difficulties than parents of children born at term, with parent-ratings indicating significantly elevated rates of everyday memory challenges in children born VP. CONCLUSIONS: Children born VP warrant long-term surveillance, as challenges associated with VP birth include memory difficulties at 13 years. This study highlights the need for greater research and clinical attention into childhood functional memory outcomes.

Parental Mental Health and Parenting Behaviors Following Very Preterm Birth: Associations in Mothers and Fathers and Implications for Child Cognitive Outcome.

OBJECTIVES: To investigate the longitudinal associations between parental mental health symptoms within 4 weeks of birth, parenting behaviors at 1 year, and child general cognitive ability at 4.5-5 years in a sample of children born very preterm (VP). This study also examined whether these associations differed based on level of family social risk. METHODS: Participants were 143 children born <30 weeks' gestation and their parents. Within 4 weeks of birth, mothers' and fathers' depressive and anxiety symptoms were assessed using the Center for Epidemiologic Studies Depression Scale and Hospital Anxiety Depression Scale-Anxiety Subscale. Parents' sensitive and structuring parenting behaviors were assessed at 1 year using the Emotional Availability Scales. Child general cognitive ability was assessed at 4.5-5 years using the Wechsler Preschool & Primary Scale of Intelligence-Fourth Edition. RESULTS: Higher maternal depressive symptoms were associated with lower levels of sensitive and structuring parenting behavior, while higher maternal anxiety symptoms were associated with higher levels of structuring parenting behavior. There was weak evidence for positive associations between mothers' sensitive parenting behavior and fathers' structuring parenting behavior and child general cognitive ability. There was also weak evidence for stronger associations between mothers' mental health symptoms, parenting behaviors, and child general cognitive ability, in families of higher compared with lower social risk. CONCLUSIONS: Depressive and anxiety symptoms experienced by mothers in the initial weeks following VP birth can have long-term effects on their parenting behaviors. Enquiring about parents' mental health during their child's hospitalization in the neonatal intensive care unit is crucial.

Thirteen-Year Outcomes of a Randomized Clinical Trial of Early Preventive Care for Very Preterm Infants and Their Parents.

OBJECTIVE: To evaluate 13-year outcomes of a randomized controlled trial of preventive care (VIBeS Plus) for infants born very preterm and their parents and examine whether possible effects of intervention varied by family social risk. STUDY DESIGN: Families were randomized to an intervention arm (n = 61) or a standard care arm (n = 59). The intervention was delivered at home by psychologists and physiotherapists over the infants' first year, focusing on infant development and parental mental health. At 13 years corrected age, cognitive, motor, and behavioral outcomes, and parental mental health were assessed. Primary estimands were between-group mean differences, estimated using multiple imputed regression models. RESULTS: Follow-up included 81 surviving children (69%). There was little evidence of benefits of the intervention for IQ, attention, executive functioning, working memory, and academic skills regardless of level of social risk. Specifically, mean differences in adolescent cognitive outcomes ranged from -2.0 units (95% CI, -9.9 to 5.9) in favor of standard treatment to 5.1 units (95% CI, -2.3 to 12.5) favoring the intervention. A group-by-social risk interaction was observed only for adolescent motor outcomes, with mean differences favoring the intervention for those at higher social risk (balance, 4.9; 95% CI, 1.3-8.5; total motor, 3.2; 95% CI, 0.3-6.2), but not those at lower social risk (balance, -0.3; 95% CI, -2.4 to 1.9; total motor, 0.03; 95% CI, -1.9 to 2.0). Mean differences in adolescent behavior and parental mental health ranged from -6.6 (95% CI -13.8, 0.5) to -0.2 (95% CI, -1.9 to 1.4) and -1.8 (95% CI, -4.1 to 0.6) to -1.7 (95% CI, -4.3 to 1.0), respectively, indicating a pattern of fewer symptoms in the intervention group. CONCLUSIONS: Benefits of the intervention persisted for adolescent behavior, with better motor outcomes observed in those from socially disadvantaged families. Replication with larger samples, multiple informant reports, and assessment of quality of life-related outcomes is warranted. TRIAL REGISTRATION: http://www.anzctr.org.au/: ACTRN12605000492651.

Parenting and Neurobehavioral Outcomes in Children Born Moderate-to-Late Preterm and at Term.

OBJECTIVES: To compare the parenting environment and the relationships between parenting behaviors and concurrent child neurobehavioral outcomes at 2 years of corrected age between children born moderate-to-late preterm (MLP; 32-36 weeks of gestation) and at term (≥37 weeks of gestation). STUDY DESIGN: Participants were 129 children born MLP and 110 children born at term and their mothers. Mothers' parenting behaviors (sensitivity, structuring, nonintrusiveness, nonhostility) were assessed at 2 years of corrected age using the Emotional Availability Scales. Child cognitive and language development were assessed using the Bayley Scales of Infant and Toddler Development, and social-emotional competence using the Infant Toddler Social and Emotional Assessment. RESULTS: Mothers of children born MLP and at term displayed similar parenting behaviors overall, with slightly lower nonintrusiveness in mothers of children born MLP (adjusted mean difference -0.32 [-0.60, -0.04]; P = .03). In both groups of children, greater maternal sensitivity was associated with better cognitive development (P < .001 MLP; P = .02 term), increased maternal structuring was associated with better social-emotional competence (P = .02 MLP; P = .03 term), and higher maternal nonintrusiveness was associated with better cognitive, language, and social-emotional outcomes (all P < .04). Greater maternal sensitivity and structuring were associated with better language development in children born MLP but not in children born at term. CONCLUSIONS: Parenting behaviors are important for neurobehavioral outcomes in children born MLP and at term. Language development may be more strongly influenced by select parenting behaviors in children born MLP compared with children born at term.

Structural Neuroplastic Responses Preserve Functional Connectivity and Neurobehavioural Outcomes in Children Born Without Corpus Callosum.

The corpus callosum is the largest white matter pathway in the brain connecting the two hemispheres. In the context of developmental absence (agenesis) of the corpus callosum (AgCC), a proposed candidate for neuroplastic response is strengthening of intrahemispheric pathways. To test this hypothesis, we assessed structural and functional connectivity in a uniquely large cohort of children with AgCC (n = 20) compared with typically developing controls (TDC, n = 29), and then examined associations with neurobehavioral outcomes using a multivariate data-driven approach (partial least squares correlation, PLSC). For structural connectivity, children with AgCC showed a significant increase in intrahemispheric connectivity in addition to a significant decrease in interhemispheric connectivity compared with TDC, in line with the aforementioned hypothesis. In contrast, for functional connectivity, children with AgCC and TDC showed a similar pattern of intrahemispheric and interhemispheric connectivity. In conclusion, we observed structural strengthening of intrahemispheric pathways in children born without corpus callosum, which seems to allow for functional connectivity comparable to a typically developing brain, and were relevant to explain neurobehavioral outcomes in this population. This neuroplasticity might be relevant to other disorders of axonal guidance, and developmental disorders in which corpus callosum alteration is observed.

Large-scale functional network dynamics in human callosal agenesis: Increased subcortical involvement and preserved laterality.

In the human brain, the corpus callosum is the major white-matter commissural tract enabling the transmission of sensory-motor, and higher level cognitive information between homotopic regions of the two cerebral hemispheres. Despite developmental absence (i.e., agenesis) of the corpus callosum (AgCC), functional connectivity is preserved, including interhemispheric connectivity. Subcortical structures have been hypothesised to provide alternative pathways to enable this preservation. To test this hypothesis, we used functional Magnetic Resonance Imaging (fMRI) recordings in children with AgCC and typically developing children, and a time-resolved approach to retrieve temporal characteristics of whole-brain functional networks. We observed an increased engagement of the cerebellum and amygdala/hippocampus networks in children with AgCC compared to typically developing children. There was little evidence that laterality of activation networks was affected in AgCC. Our findings support the hypothesis that subcortical structures play an essential role in the functional reconfiguration of the brain in the absence of a corpus callosum.

Investigating the brain structural connectome following working memory training in children born extremely preterm or extremely low birth weight.

Children born extremely preterm (EP, <28 weeks' gestation) or extremely low birth weight (ELBW, <1,000 g) are a vulnerable population at high risk of working memory impairments. We aimed to examine changes in the brain structural connectivity networks thought to underlie working memory performance, after completion of a working memory training program (Cogmed) compared with a placebo program in EP/ELBW children. This was a double-blind, placebo-controlled randomized trial (the Improving Memory in a Preterm Randomised Intervention Trial). Children born EP/ELBW received either the Cogmed or placebo program at 7 years of age (n = 91). A subset of children had magnetic resonance imaging of the brain immediately pre- and 2 weeks post-training (Cogmed n = 28; placebo n = 27). T1 -weighted and diffusion-weighted images were used to perform graph theoretical analysis of structural connectivity networks. Changes from pre-training to post-training in structural connectivity metrics were generally similar between randomized groups. There was little evidence that changes in structural connectivity metrics were related to changes in working memory performance from pre- to post-training. Overall, our results provide little evidence that the Cogmed working memory training program has training-specific effects on structural connectivity networks in EP/ELBW children.

Revisiting brain rewiring and plasticity in children born without corpus callosum.

The corpus callosum is the largest white matter pathway connecting homologous structures of the two cerebral hemispheres. Remarkably, children and adults with developmental absence of the corpus callosum (callosal dysgenesis, CD) show typical interhemispheric integration, which is classically impaired in adult split-brain patients, for whom the corpus callosum is surgically severed. Tovar-Moll and colleagues (2014) proposed alternative neural pathways involved in the preservation of interhemispheric transfer. In a sample of six adults with CD, they revealed two homotopic bundles crossing the midline via the anterior and posterior commissures and connecting parietal cortices, and the microstructural properties of these aberrant bundles were associated with functional connectivity of these regions. The aberrant bundles were specific to CD and not visualised in healthy brains. We extended this study in a developmental cohort of 20 children with CD and 29 typically developing controls (TDC). The two anomalous white-matter bundles were visualised using tractography. Associations between structural properties of these bundles and their regional functional connectivity were explored. The proposed atypical bundles were observed in 30% of our CD cohort crossing via the anterior commissure, and in 30% crossing via the posterior commissure (also observed in 6.9% of TDC). However, the structural property measures of these bundles were not associated with parietal functional connectivity, bringing into question their role and implication for interhemispheric functional connectivity in CD. It is possible that very early disruption of embryological callosal development enhances neuroplasticity and facilitates the formation of these proposed alternative neural pathways, but further evidence is needed.

Working memory training and brain structure and function in extremely preterm or extremely low birth weight children.

This study in children born extremely preterm (EP; <28 weeks' gestational age) or extremely low birth weight (ELBW; <1,000 g) investigated whether adaptive working memory training using Cogmed® is associated with structural and/or functional brain changes compared with a placebo program. Ninety-one EP/ELBW children were recruited at a mean (standard deviation) age of 7.8 (0.4) years. Children were randomly allocated to Cogmed or placebo (45-min sessions, 5 days a week over 5-7 weeks). A subset had usable magnetic resonance imaging (MRI) data pretraining and 2 weeks posttraining (structural, n = 48; diffusion, n = 43; task-based functional, n = 18). Statistical analyses examined whether cortical morphometry, white matter microstructure and blood oxygenation level-dependent (BOLD) signal during an n-back working memory task changed from pretraining to posttraining in the Cogmed and placebo groups separately. Interaction analyses between time point and group were then performed. There was a significant increase in neurite density in several white matter regions from pretraining to posttraining in both the Cogmed and placebo groups. BOLD signal in the posterior cingulate and precuneus cortices during the n-back task increased from pretraining to posttraining in the Cogmed but not placebo group. Evidence for group-by-time interactions for the MRI measures was weak, suggesting that brain changes generally did not differ between Cogmed and placebo groups. Overall, while some structural and functional MRI changes between the pretraining and posttraining period in EP/ELBW children were observed, there was little evidence of training-induced neuroplasticity, with changes generally identified in both groups. Trial registration Australian New Zealand Clinical Trials Registry, anzctr.org.au; ACTRN12612000124831.

Mental Health Trajectories of Fathers Following Very Preterm Birth: Associations With Parenting.

OBJECTIVE: Mothers of infants born very preterm (VPT) are at high risk of mental health difficulties. However, less is known about the course of fathers' depressive and anxiety symptoms over time, and the implications this may have for early parenting behaviors. METHODS: In total, 100 fathers of 125 infants born VPT (<30 weeks' gestation) completed questionnaires assessing depressive and anxiety symptoms shortly after their infant's birth, and when their infant reached term-equivalent age, 3 months, 6 months, and 12 months' corrected age. At 12 months' corrected age, fathers' parenting behaviors were assessed using the Emotional Availability Scales. Longitudinal latent class analysis was used to identify trajectories of fathers' depressive and anxiety symptoms, and linear regression equations examined relationships between these trajectories and fathers' parenting behaviors. RESULTS: For both depressive and anxiety symptoms, two distinct trajectories were identified. For depression, most fathers were assigned to the persistently low symptom trajectory (82%), while the remainder were assigned to the persistently high symptom trajectory (18%). For anxiety, 49% of fathers were assigned to the persistently low symptom trajectory, while 51% were assigned to the trajectory characterized by moderate symptoms over the first postnatal year. There were no significant differences in parenting behaviors between fathers assigned to the different depressive and anxiety symptom trajectories. CONCLUSIONS: Fathers of infants born VPT are at risk of chronic depressive and anxiety symptoms over the first postnatal year, highlighting the need for screening and ongoing support.

Influence of Fathers' Early Parenting on the Development of Children Born Very Preterm and Full Term.

OBJECTIVES: To examine factors associated with fathers' early parenting behaviors (including very preterm [VPT] birth, familial social risk, child sex, and child medical risk), and the relationship between fathers' early parenting behaviors and later child development. STUDY DESIGN: Participants were 81 VPT (born <30 weeks of gestation) and 39 full-term father-child dyads. Parenting behaviors (sensitivity, structuring, nonintrusiveness, nonhostility) were assessed at 12 months of corrected age using the Emotional Availability Scales, with scores ranging from 1 (low) to 7 (high). At 24 months of corrected age, child cognitive, language, motor, and social-emotional development were assessed. Results are presented as (regression coefficients; 95% CIs). RESULTS: There was little evidence that VPT birth, familial social risk, or child medical risk were associated with fathers' parenting behaviors. Fathers of girls tended to be more sensitive (0.42; 0.18, 0.65), less intrusive (0.36; 0.04, 0.70), and less hostile (0.26; 0.01, 0.50) compared with fathers of boys. Higher structuring was associated with more optimal cognitive (3.29; 1.25, 5.34), and language development (4.69; 2.26, 7.14). Higher sensitivity was associated with more optimal language development 3.35 (0.95, 5.75), and more intrusive behavior was associated with more externalizing symptoms (-1.68; -3.06, -0.31). CONCLUSIONS: Early parenting did not differ between fathers with VPT and full-term children, but fathers' parenting did vary according to child sex. Fathers' early parenting was associated with future neurodevelopment, reinforcing the need to support fathers' parenting, and include fathers in early intervention programs.

Long-Term Academic Functioning Following Cogmed Working Memory Training for Children Born Extremely Preterm: A Randomized Controlled Trial.

OBJECTIVE: To assess the effectiveness of Cogmed Working Memory Training compared with a placebo program in improving academic functioning 24 months post-training in extremely preterm/extremely low birth weight 7-year-olds. STUDY DESIGN: A multicenter double-blind, placebo-controlled randomized controlled trial was conducted across all tertiary neonatal hospitals in the state of Victoria, Australia. Participants were 91 extremely preterm/extremely low birth weight 7-year-old children born in Victoria in 2005. Children were randomly assigned to either the Cogmed or placebo arm and completed the Cogmed or placebo program (20-25 sessions of 35-40 minutes duration) at home over 5-7 weeks. Academic achievement (word reading, spelling, sentence comprehension, and mathematics) was assessed 24 months post-training, as well as at 2 weeks and 12 months post-training, via standardized testing inclusive of working memory, attention, and executive behavior assessments. Data were analyzed using an intention-to-treat approach with mixed-effects modeling. RESULTS: There was little evidence of any benefits of Cogmed on academic functioning 24 months post-training, as well as on working memory, attention, or executive behavior at any age up to 24 months post-training compared with the placebo program. CONCLUSIONS: We currently do not recommend administration of Cogmed for early school-aged children born extremely preterm/extremely low birth weight to improve academic functioning. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12612000124831.

A Neuropsychological Profile for Agenesis of the Corpus Callosum? Cognitive, Academic, Executive, Social, and Behavioral Functioning in School-Age Children.

OBJECTIVES: Agenesis of the corpus callosum (AgCC), characterized by developmental absence of the corpus callosum, is one of the most common congenital brain malformations. To date, there are limited data on the neuropsychological consequences of AgCC and factors that modulate different outcomes, especially in children. This study aimed to describe general intellectual, academic, executive, social and behavioral functioning in a cohort of school-aged children presenting for clinical services to a hospital and diagnosed with AgCC. The influences of age, social risk and neurological factors were examined. METHODS: Twenty-eight school-aged children (8 to 17 years) diagnosed with AgCC completed tests of general intelligence (IQ) and academic functioning. Executive, social and behavioral functioning in daily life, and social risk, were estimated from parent and teacher rated questionnaires. MRI findings reviewed by a pediatric neurologist confirmed diagnosis and identified brain characteristics. Clinical details including the presence of epilepsy and diagnosed genetic condition were obtained from medical records. RESULTS: In our cohort, ~50% of children experienced general intellectual, academic, executive, social and/or behavioral difficulties and ~20% were functioning at a level comparable to typically developing children. Social risk was important for understanding variability in neuropsychological outcomes. Brain anomalies and complete AgCC were associated with lower mathematics performance and poorer executive functioning. CONCLUSIONS: This is the first comprehensive report of general intellectual, academic, executive social and behavioral consequences of AgCC in school-aged children. The findings have important clinical implications, suggesting that support to families and targeted intervention could promote positive neuropsychological functioning in children with AgCC who come to clinical attention. (JINS, 2018, 24, 445-455).

Goal Setting Deficits at 13 Years in Very Preterm Born Children.

OBJECTIVES: Preterm children demonstrate deficits in executive functions including inhibition, working memory, and cognitive flexibility; however, their goal setting abilities (planning, organization, strategic reasoning) remain unclear. This study compared goal setting abilities between very preterm (VP: <30 weeks/<1250 grams) and term born controls during late childhood. Additionally, early risk factors (neonatal brain abnormalities, medical complications, and sex) were examined in relationship to goal setting outcomes within the VP group. METHODS: Participants included 177 VP and 61 full-term born control children aged 13 years. Goal setting was assessed using several measures of planning, organization, and strategic reasoning. Parents also completed the Behavior Rating Inventory of Executive Function. Regression models were performed to compare groups, with secondary analyses adjusting for potential confounders (sex and social risk), and excluding children with major neurosensory impairment and/or IQ<70. Within the VP group, regression models were performed to examine the relationship between brain abnormalities, medical complications, and sex, on goal setting scores. RESULTS: The VP group demonstrated a clear pattern of impairment and inefficiency across goal setting measures, consistent with parental report, compared with their full-term born peers. Within the VP group, moderate/severe brain abnormalities on neonatal MRI predicted adverse goal setting outcomes at 13. CONCLUSIONS: Goal setting difficulties are a significant area of concern in VP children during late childhood. These difficulties are associated with neonatal brain abnormalities, and are likely to have functional consequences academically, socially and vocationally. (JINS, 2018, 24, 372-381).

Predicting neurocognitive and behavioural outcome after early brain insult.

AIMS: The aims of the study were to investigate (1) the impact of age at brain insult on functional outcome and (2) the influence of insult and environmental factors on cognitive and behavioural outcomes. METHOD: The study was a cross-sectional, retrospective observational study, involving 138 children (76 males, 62 females; mean age 13y 1mo, SD 1y 11mo, range 10­16y) with magnetic resonance imaging (MRI) evidence of focal brain insult sustained from the first trimester of pregnancy to adolescence. Children underwent MRI and intellectual, executive, behavioural, and social evaluation. Outcome predictors were insult (lesion location, laterality, and extent, history of seizures, age at insult) and environmental (social risk and family function) factors. RESULTS: Focal insult before the age of 3 years was associated with poorer outcomes than insult after the age of 3 years across all domains. For IQ outcomes, insult characteristics and seizures were highly predictive. For executive and behavioural domains, family function and social risk had the greatest impact. Earlier age at insult predicted poorer social competence. INTERPRETATION Focal brain insult before age 3 years has devastating consequences for children's development. Findings suggest that greater emphasis should be placed on providing early intervention for children who sustain early focal brain insults.

Language and communication functioning in children and adolescents with agenesis of the corpus callosum.

The corpus callosum, the largest white matter inter-hemispheric pathway, is involved in language and communication. In a cohort of 15 children and adolescents (8-15 years) with developmental absence of the corpus callosum (AgCC), this study aimed to describe language and everyday communication functioning, and explored the role of anatomical factors, social risk, and non-verbal IQ in these outcomes. Standardised measures of language and everyday communication functioning, intellectual ability and social risk were used. AgCC classification and anterior commissure volume, a potential alternative pathway, were extracted from T1-weighted images. Participants with AgCC showed reduced receptive and expressive language compared with test norms, and high rates of language and communication impairments. Complete AgCC, higher social risk and lower non-verbal IQ were associated with communication difficulties. Anterior commissure volume was not associated with language and communication. Recognising heterogeneity in language and communication functioning enhances our understanding and suggests specific focuses for potential interventions.

Exploring Working Memory Capacity and Efficiency Processes to Understand Working Memory Training Outcomes in Primary School Children.

Despite the abundance of research evaluating working memory training outcomes in children, few studies have examined the underlying cognitive mechanisms. This study aimed to contribute understanding by exploring whether working memory capacity (maximum span) and/or efficiency (basic and cognitive processing speeds), two proposed cognitive mechanisms, are associated with children's working memory performance immediately and 6-months post-intervention. We used data from a previous trial in primary school children (7-11 years) who completed working memory training (n = 52) or an active control (n = 36), comprising 10 sessions (each 20-minutes) in class over two weeks. Children completed five working memory measures at baseline, immediately and 6-months post-intervention: two Backwards Span and two Following Instructions measures (same paradigms as training activities), and one n-back measure (different paradigm). Maximum span, basic and cognitive processing speeds, and performance were calculated for each measure. Associations between change in maximum span, processing speeds and change in performance on the working memory measures from baseline to immediately and 6-months post-intervention did not differ between groups (all p < .05). Maximum span, processing speeds and performance on working memory measures did not differ between groups. Findings provide little evidence that the studied capacity or efficiency processes contribute to understanding working memory training outcomes in primary school children. Furthermore, working memory training did not have benefits for children's working capacity, efficiency or performance up to 6-months post-intervention. It is of interest for future studies to explore cognitive mechanisms, including strategy use, maximum span and information processing, in datasets where training effects are observed.

Does the Bayley-III Motor Scale at 2 years predict motor outcome at 4 years in very preterm children?

AIM: To assess the predictive validity of the Bayley Scales of Infant and Toddler Development - Third Edition (Bayley-III) for later motor outcome. METHOD: Ninety-six infants (49 males, 47 females) born at less than 30 weeks' gestation admitted to two tertiary hospitals in Melbourne, Australia, were assessed with the Bayley-III Motor Scale at 2 years' corrected age and were classified as suspect or definite motor impairment if they scored less than -1 or -2 standard deviations respectively, relative to the test mean. At 4 years' corrected age, children completed Movement Assessment Battery for Children - Second Edition (MABC-2); for the total motor score, cut-offs of not more than the 15th were used to classify motor development and cut-offs of not more than the 15th centile were classified as having a significant movement difficulty. RESULTS: Of the 96 children assessed at both ages, at 2 years 9% had suspect and 4% had definite motor impairment; however, by 4 years, rates had increased to 22% and 19% respectively. The specificity of the Bayley-III for motor impairments for later motor outcome was excellent (ranging from 94 to 100% for cerebral palsy [CP] and 97 to 100% for motor impairment), although the sensitivity was low (ranging from 67 to 83% for CP and 18 to 37% for motor impairment); many children with later impairment were not identified by the Bayley-III. INTERPRETATION: The Bayley-III Motor Scale at 2 years underestimates later rates of motor impairment, particularly in the absence of CP at 4 years on the MABC-2 total motor score in children born at less than 30 weeks' gestational age.

A neural index of inefficient evidence accumulation in dyslexia underlying slow perceptual decision making.

Visual processing deficits have been widely reported in developmental dyslexia however the locus of cognitive dysfunction remains unclear. Here, we examined the neural correlates of perceptual decision-making using a dot-motion task and electroencephalography (EEG) and investigated whether presenting deficits were unique to children with dyslexia or if they were also evident in other, typically developing children with equally immature reading systems. Sixty-eight children participated: 32 with dyslexia (DD; 16 females); 21 age-matched controls (AM; 11 females) and 15 reading-matched controls (RM; 9 females). All participants completed a bilaterally presented random-dot-motion task while EEG was recorded. Neural signatures of low level sensory processing (steady state visual evoked potentials; SSVEPs), pre-target attentional bias (posterior α power), attentional orienting (N2), evidence accumulation (centro-parietal positive decision signal; CPP) and execution of a motor response (ß) were obtained to dissect the temporal sequence of perceptual decision-making. Reading profile provided a score of relative lexical and sublexical skills for each participant. Although all groups performed comparably in terms of task accuracy and false alarm rate, the DD group were slower and demonstrated an earlier peak latency, reduced slope and lower amplitude of the CPP compared with both AM and RM controls. Reading profile was found to moderate the relationship between word reading ability, reaction time as well as CPP indices showing that lexical dyslexics responded more slowly and had a shallower slope, reduced amplitude and earlier latency of CPP waveforms than sublexical dyslexics. These findings suggest that children with dyslexia, particularly those with relatively poorer lexical abilities, have a reduced rate and peak of evidence accumulation as denoted by CPP markers yet remain slow in their overt response. This is in keeping with hypotheses that children with dyslexia have impairment in effectively sampling and processing evidence about visual motion stimuli.