Comorbid Word Reading and Mathematics Computation Difficulty at Start of First Grade

The purpose of this analysis was to describe cognitive processes associated with comorbid difficulty between word reading (WR) and mathematics computation (MC) at the start of first grade among children selected for WR and MC delays. A sample of 234 children (mean age 6.50 years, SD = 0.31) was assessed on WR, MC, core cognitive processes (phonological processing, rapid automatized naming, verbal counting [VC]), and domain-general cognitive processes (working memory, oral language, nonverbal reasoning, attentive behavior). Structural equation modeling was used to predict a latent Comorbidity factor, which modeled shared variance between WR and MC, and to identify processes associated with that Comorbidity factor. Results identified each of the core cognitive processes, especially VC, and each of the domain-general cognitive processes, especially working memory, as explaining shared variance between WR and MC. Implications for understanding comorbid difficulty at the start of first grade and designing coordinated first-grade interventions are discussed.

An Evaluation of the Structure of Attention in Adolescence

This study evaluated the factor structure of attention, considering internal and external attention, and juxtaposed alongside processing speed (PS) and working memory (WM). We expected the hypothesized model to fit better than unitary or method factors. We included 27 measures with 212 Hispanic middle schoolers from Spanish-speaking backgrounds, where a substantial proportion were at risk for learning difficulties. Confirmatory factor analytic models separated factors of PS and WM, but the final model did not align with theoretical predictions; rather only measurement factors emerged. Findings extend and refine our understanding of the structure of attention in adolescents.

Visual attention and reading: A test of their relation across paradigms

Relations of visual attention to reading have long been hypothesized; however, findings in this literature are quite mixed. These relations have been investigated using several different visual attention paradigms and with variable controls for other competing reading-related processes. We extended current knowledge by evaluating four of the key visual attention paradigms used in this research-visual attention span, attention blink, visual search, and visuospatial attention-in a single study. We tested the relations of these to reading in 90 middle schoolers at high risk for reading difficulties while considering their effect in the context of known language predictors. Performance on visual-spatial, visual search, and attentional blink paradigms showed weak nonsignificant relations to reading. Visual attention span tasks showed robust relations to reading even when controlling for language, but only when stimuli were alphanumeric. Although further exploration of visual attention in relation to reading may be warranted, the robustness of this relationship appears to be questionable, particularly beyond methodological factors associated with the measurement of visual attention. Findings extend and refine our understanding of the contribution of attention to reading skill and raise questions about the mechanism by which visual attention is purported to affect reading.

The influence of student engagement on the effects of an inferential reading comprehension intervention for struggling middle school readers

Although many students benefit from evidence-based reading comprehension interventions, not all students will exhibit adequate response. Moderation analysis provides a statistical approach to examine for whom and under what conditions interventions are most effective. Conducted within a parent project, which investigated the effects of an inferential reading comprehension intervention, the current study examined factors related to the deployment of students' attention as well as language status that might be associated with differential response to intervention. Sixty-six struggling middle school readers were randomly assigned to a computerized version of the intervention, a teacher-led version, or business-as-usual (BaU) control instruction. The influence of language status (i.e., English Learner status) and pre-intervention levels of mind-wandering, anxiety, and mindset on the effects of the inferential reading comprehension intervention were examined. There were no moderator effects for the teacher-led group compared to the BaU control. Conversely, anxiety, mind-wandering, and language status moderated the effects of the computer-led intervention for some reading and inference-making outcomes. The computer-led intervention was associated with improved inference-making for students with higher levels of self-reported anxiety and mind-wandering. In contrast, the computer-led intervention was less beneficial than BaU instruction for English learners. Findings are discussed with respect to how these factors might be relevant for interpreting the effects of interventions for struggling middle school readers in general, and for English learners in particular. The findings also point to the importance of considering the characteristics of both student and instructional features in the creation and testing of reading comprehension interventions.

The Role of Knowledge Availability in Forming Inferences with Rural Middle Grade English Learners

We investigated differences in knowledge-based inferencing between rural, middle grade monolingual English-speaking students and English learners. Students were introduced to facts about an imaginary planet Gan followed by a multi-episode story about Gan. Participants were tested on the accuracy of fact recall and inferences using this knowledge at three time points (i.e., immediate, one-week, and one-month follow-up). Results show that monolingual English-speaking students significantly outperformed English learners on the inference task. Both subgroups made elaborative inferences more accurately than coherence. Students' ability to recall knowledge base facts was the strongest predictor of their ability to accurately make inferences using this knowledge at each time point.

Effects of semantic reinforcement, semantic discrimination, and affix frequency on new word learning in skilled and less skilled readers in Grades 6 to 12

Two approaches to word learning were investigated in 1214 6th- to 12th-grade students. Definitions were provided, followed either by two sentences that were semantically correct exemplars, called semantic reinforcement learning, or by one correct sentence and a contrasting incorrect sentence (i.e., example followed by a structurally aligned non-example), called semantic discrimination learning. Type of learning was blocked, and examples and non-examples were explained. Effects of affix frequency were also assessed. Students were taught words, followed by assessments of abilities to recall the meanings of the words immediately after learning them, to choose the correct words among distractors to match given definitions after all words had been instructed, and to judge the semantic veracity of new sentences containing taught words 1-3 days later. Explanatory item response models were used to predict word learning using student and item characteristics along with their interactions. Few grade-related differences emerged. Higher-frequency affixes were generally beneficial for learning and retention across comprehension skill levels and measures. Immediate recall of word meanings was facilitated by semantic reinforcement learning. In contrast, performance after all the words had been instructed was facilitated by semantic discrimination learning, but only for more highly skilled comprehenders. The ability to learn the meanings of new words accounted for unique variance on one measure of reading comprehension, controlling for decoding, previously acquired vocabulary knowledge, and working memory. Results are discussed with reference to models of vocabulary learning and implications for vocabulary instruction for adolescents.

Sustained attention and behavioral ratings of attention in struggling readers

Attention is correlated with reading, but the extent to which behavioral ratings and sustained attention relate to reading skills is unclear. We assessed 245 4th and 5th grade struggling readers (mean age = 10.3 years) on behavioral ratings of attention, sustained attention, and reading over a school year. Contributions of behavioral ratings and sustained attention were considered cross-sectionally and longitudinally in the context of other important predictors of reading. Results suggest that sustained measures and behavioral ratings assess distinct, yet overlapping, aspects of attention. Both types of attention accounted for unique variance in comprehension, but not word reading accuracy or fluency, when evaluated cross-sectionally. Results also support the role of behavioral ratings of attention in fluency and in comprehension growth. Findings suggest that multidimensional assessment of attention is useful when considering its relation to reading, and highlights the need to integrate conceptualizations of attention that arise from different theoretical approaches.

Neuropsychological care guidelines for people with spina bifida

While the neuropsychological profile for individuals with Spina Bifida (SB) can vary, often certain patterns of strengths and weaknesses are evident across the lifespan. Understanding variability related to neural structure, genetics, ethnicity, and the environment is key to understanding individual differences in outcomes and can be vital in planning interventions and tracking progress. This article outlines the SB Guideline for the Neuropsychological Care of People with Spina Bifida from the 2018 Spina Bifida Association's Fourth Edition of the Guidelines for the Care of People with Spina Bifida and acknowledges that further research in SB neurocognitive profiles is warranted.

A framework for executive function in the late elementary years

OBJECTIVE

Executive function (EF) is a commonly used but difficult to operationalize construct. In this study, we considered EF and related components as they are commonly presented in the neuropsychological literature, as well as the literatures of developmental, educational, and cognitive psychology. These components have not previously been examined simultaneously, particularly with this level of comprehensiveness, and/or at this age range or with this sample size. We expected that the EF components would be separate but related, and that a bifactor model would best represent the data relative to alternative models.

METHOD

We assessed EF with 27 measures in a large sample (N = 846) of late elementary school-age children, many of whom were struggling in reading, and who were demographically diverse. We tested structural models of EF, from unitary models to methodological models, utilizing model-comparison factor analytic techniques. We examined both a common factor as well as a bifactor structure.

RESULTS

Initial models showed strong overlap among several latent EF variables. The final model was a bifactor model with a common EF, and five specific EF factors (working memory-span/manipulation and planning; working memory-updating; generative fluency, self-regulated learning; metacognition).

CONCLUSIONS

Results speak to the commonality and potential separability of EF. These results are discussed in light of prevailing models of EF and how EF might be used for structure/description, prediction, and for identifying its mechanism for relevant outcomes. (PsycINFO Database Record

Executive Function: Association with Multiple Reading Skills

Executive function (EF) is related to reading. However, there is a lack of clarity around (a) the relative contribution of different components of EF to different reading components (word reading, fluency, comprehension), and (b) how EF operates in the context of known strong language predictors (e.g., components of the Simple View of Reading or SVR), and other skills theoretically related to reading (e.g., vocabulary, processing speed) and/or to EF (e.g., short-term memory, motor function). In a large sample of 3rd to 5th graders oversampled for struggling readers, this paper evaluates the impact of EF derived from a bifactor model (Cirino, Ahmed, Miciak, Taylor, Gerst, & Barnes, 2018) in the context of well-known covariates and demographics. Beyond common EF, five specific factors (two related to working memory, and factors of fluency, self-regulated learning, and behavioral inattention/metacognition) were addressed. EF consistently showed a unique contribution to already-strong predictive models for all reading outcomes; for reading comprehension, EF interacted with SVR indices (word reading and listening comprehension). The findings extend and refine our understanding of the contribution of EF to reading skill.

Recovery of Working Memory Following Pediatric Traumatic Brain Injury: A Longitudinal Analysis

In a prospective longitudinal study, the trajectory of verbal and visual-spatial working memory (WM) development was examined 2-, 6-, 12-, and 24-months following complicated-mild to severe pediatric traumatic brain injury (TBI; n = 55) relative to an orthopedic injury comparison group (n = 47). Individual growth curve modeling revealed an interaction of age, severity, and time for verbal, but not visual-spatial WM. The youngest children with severe TBI had the lowest scores and slowest verbal WM growth. WM outcome is best understood in light of age at injury and TBI severity. Findings support the early vulnerability hypothesis and highlight the need for long-term follow-up.

Executive Function, Self-Regulated Learning, and Reading Comprehension: A Training Study

The goal of this study was to evaluate the extent to which training that emphasizes the process of executive function (EF) and self-regulated learning (SRL) would result in increased reading comprehension; we also evaluated interrelationships of EF, SRL, and reading. We report an experiment ( N = 75 fourth graders) that contrasted two researcher-implemented conditions (text-based reading [TB] and text-based reading plus executive function [TB+EF]) to a control. We also evaluated relationships among measures of SRL, EF, and reading. Both the TB and TB+EF groups outperformed the control group for proximal text comprehension (where the topic was similar to that covered in training) and background knowledge related to it, but the two researcher-led groups performed similarly. There were no significant differences for less proximal text, and again similar performance for both TB and TB+EF. Correlations among measures were weak in general, although the pattern was similar to that found in the extant literature. The findings speak to the difficulty in separating these components from those of strong instruction more generally. The relationships of these constructs to reading comprehension will likely be enhanced by more sensitive measurement of EF and reading comprehension, particularly where tied to active treatment components.

Early numeracy skills in preschool-aged children: a review of neurocognitive findings and implications for assessment and intervention

OBJECTIVES

The goals are to (1) provide a review of the typical and atypical development of early numeracy; (2) present what is known about the neurocognitive underpinnings of early numeracy; and (3) discuss the implications for early assessment and intervention.

METHOD

Studies on the development of typical and atypical early numeracy are reviewed with a particular focus on longitudinal findings including those from our work on spina bifida myelomeningocele. Implications of this research for assessment are presented. The paper ends with a discussion of early math interventions.

RESULTS

Learning to count, identify numbers, and compare and manipulate quantities are key early numeracy skills. These are powerful predictors of school-age mathematical learning and performance. General neurocognitive abilities such as working memory and language, are also important for the development of early numeracy. It is recommended that early assessment for risk of mathematical learning difficulties include tests of both early number knowledge and key neurocognitive abilities. Math-specific interventions are most effective for improving early numeracy. There is currently little evidence that training of general cognitive functions transfers to mathematical learning.

CONCLUSION

Understanding the development of early numeracy skills and their neurocognitive predictors offer important insights into early assessment and intervention for children at risk for or with mathematical learning difficulties.

Cognitive Difficulties in Struggling Comprehenders and their Relation to Reading Comprehension: A Comparison of Group Selection and Regression-Based Models

Difficulties suppressing previously encountered, but currently irrelevant information from working memory characterize less skilled comprehenders in studies in which they are matched to skilled comprehenders on word decoding and nonverbal IQ. These "extreme" group designs are associated with several methodological issues. When sample size permits, regression approaches permit a more accurate estimation of effects. Using data for students in grades 6 to 12 (n = 766), regression techniques assessed the significance and size of the relation of suppression to reading comprehension across the distribution of comprehension skill. After accounting for decoding efficiency and nonverbal IQ, suppression, measured by performance on a verbal proactive interference task, accounted for a small amount of significant unique variance in comprehension (less than 1%). A comparison of suppression in less skilled comprehenders matched to more skilled comprehenders (48 per group) on age, word reading efficiency and nonverbal IQ did not show significant group differences in suppression. The implications of the findings for theories of reading comprehension and for informing comprehension assessment and intervention are discussed.

Does processing speed mediate the effect of pediatric traumatic brain injury on working memory?

OBJECTIVE

Processing speed (PS) and working memory (WM), core abilities that support learning, are vulnerable to disruption following traumatic brain injury (TBI). Developmental increases in WM are related to age-related changes in PS. The purpose of this study was to investigate whether WM deficits in children with TBI are mediated by PS.

METHOD

The performance of children with complicated mild, moderate, and severe TBI (n = 77) was examined relative to an orthopedic injury (n = 30) and a healthy comparison group (n = 40) an average of 4 years after injury (range 8 months to 12 years). Coding was utilized as a measure of PS, while the WM measures included complex verbal and visual-spatial span tasks with parallel processing requirements. Mediation analysis examined whether TBI might have an indirect effect on WM through PS.

RESULTS

Children in the TBI group performed more poorly than the combined comparison groups on coding and visual-spatial WM. Verbal WM scores were lower in TBI and the healthy comparison relative to the orthopedic group. TBI severity group differences were found on coding, but not WM measures. The relation between coding and both the WM tasks was similar. Bootstrap regression analyses suggested that PS, as measured by coding, might partially mediate the effect of group performance on WM.

CONCLUSIONS

TBI disrupts core PS and WM abilities that scaffold more complex abilities. Importantly, slowed PS was associated with WM deficits commonly identified following pediatric TBI. Implications of our findings regarding the relation between PS and WM may suggest interventions for children and adolescents following TBI.

Parenting Predictors of Delay Inhibition in Socioeconomically Disadvantaged Preschoolers

This study examined longitudinal associations between specific parenting factors and delay inhibition in socioeconomically disadvantaged preschoolers. At Time 1, parents and 2- to 4-year-old children (mean age = 3.21 years; N = 247) participated in a videotaped parent-child free play session, and children completed delay inhibition tasks (gift delay-wrap, gift delay-bow, and snack delay tasks). Three months later, at Time 2, children completed the same set of tasks. Parental responsiveness was coded from the parent-child free play sessions, and parental directive language was coded from transcripts of a subset of 127 of these sessions. Structural equation modeling was used, and covariates included age, gender, language skills, parental education, and Time 1 delay inhibition. Results indicated that in separate models, Time 1 parental directive language was significantly negatively associated with Time 2 delay inhibition, and Time 1 parental responsiveness was significantly positively associated with Time 2 delay inhibition. When these parenting factors were entered simultaneously, Time 1 parental directive language significantly predicted Time 2 delay inhibition whereas Time 1 parental responsiveness was no longer significant. Findings suggest that parental language that modulates the amount of autonomy allotted the child may be an important predictor of early delay inhibition skills.

Neurocognitive predictors of mathematical processing in school-aged children with spina bifida and their typically developing peers: Attention, working memory, and fine motor skills

OBJECTIVE

Math and attention are related in neurobiological and behavioral models of mathematical cognition. This study employed model-driven assessments of attention and math in children with spina bifida myelomeningocele (SBM), who have known math difficulties and specific attentional deficits, to more directly examine putative relations between attention and mathematical processing. The relation of other domain general abilities and math was also investigated.

METHOD

Participants were 9.5-year-old children with SBM (n = 44) and typically developing children (n = 50). Participants were administered experimental exact and approximate arithmetic tasks, and standardized measures of math fluency and calculation. Cognitive measures included the Attention Network Test (ANT), and standardized measures of fine motor skills, verbal working memory (WM), and visual-spatial WM.

RESULTS

Children with SBM performed similarly to peers on exact arithmetic, but more poorly on approximate and standardized arithmetic measures. On the ANT, children with SBM differed from controls on orienting attention, but not on alerting and executive attention. Multiple mediation models showed that fine motor skills and verbal WM mediated the relation of group to approximate arithmetic; fine motor skills and visual-spatial WM mediated the relation of group to math fluency; and verbal and visual-spatial WM mediated the relation of group to math calculation. Attention was not a significant mediator of the effects of group for any aspect of math in this study.

CONCLUSION

Results are discussed with reference to models of attention, WM, and mathematical cognition.

The Relation of Knowledge-Text Integration Processes and Reading Comprehension in 7th- to 12th-Grade Students

The integration of knowledge during reading was tested in 1,109 secondary school students. Reading times for the second sentence in a pair (Jane's headache went away) were compared in conditions where the first sentence was either causally or temporally related to the first sentence (Jane took an aspirin vs. Jane looked for an aspirin). Mixed-effects explanatory item response models revealed that at higher comprehension levels, sentences were read more quickly in the causal condition. There were no condition-related reading time differences at lower comprehension levels. This interaction held with comprehension- and inference-related factors (working memory, word and world knowledge, and word reading efficiency) in the models. Less skilled comprehenders have difficulty in knowledge-text integration processes that facilitate sentence processing during reading.

Mathematics development and difficulties: the role of visual-spatial perception and other cognitive skills

Several neurocognitive abilities, including visual-spatial and language-based processes, attention, and fine motor/finger skills, are thought to play important roles in mathematical development and disability. Evidence for relations of specific neurocognitive skills and mathematical development and disability is presented, with a particular emphasis on findings from longitudinal studies. Why these particular neurocognitive skills are related to math is also discussed. We suggest that mathematics learning in children with congenital and acquired neurodevelopmental disorders, including children treated for cancer, is particularly vulnerable to disruption because these disorders often affect one or more of the neurocognitive systems that support math learning and performance. Implications for assessment of and interventions for math difficulties are discussed. The article ends with implications for mathematical functioning in children treated for acute lymphoblastic leukemia and brain tumors.

Associations Among Parental Education, Home Environment Quality, Effortful Control, and Preacademic Knowledge

This study used a longitudinal design to examine whether effortful control mediated the associations of parental education and home environment quality with preacademic knowledge in toddlers and young preschoolers. The sample consisted of 226 children (2 to 4 years of age at T1) from socioeconomically disadvantaged backgrounds. Parents provided data on parent education and home environment quality. Children completed effortful control, early literacy, and early math assessments. T2 effortful control partially mediated the associations of T1 parental education and T1 home environment quality with T3 emergent literacy after accounting for child age, gender, race/ethnicity, T1 effortful control, and T2 early literacy. T2 effortful control partially mediated the association between T1 parental education and T3 emergent math after accounting for child age, gender, race/ethnicity, T1 effortful control, and T2 early math. Prior to entry into preschool, parental education and home environment quality may shape effortful control which in turn influences preacademic knowledge.

The Contribution of Attentional Control and Working Memory to Reading Comprehension and Decoding

Little is known about how specific components of working memory, namely, attentional processes including response inhibition, sustained attention, and cognitive inhibition, are related to reading decoding and comprehension. The current study evaluated the relations of reading comprehension, decoding, working memory, and attentional control in 1,134 adolescent students. Path analyses were used to assess the direct and indirect effects of working memory and aspects of attentional control on reading comprehension and decoding. There were significant direct effects of working memory, sustained attention, and cognitive inhibition on reading comprehension, but not decoding. There was a significant direct effect of working memory and response inhibition on decoding, but not comprehension. These results suggest that different aspects of attentional control are important for decoding versus comprehension.

Longitudinal mediators of achievement in mathematics and reading in typical and atypical development

Longitudinal studies of neurodevelopmental disorders that are diagnosed at or before birth and are associated with specific learning difficulties at school-age provide one method for investigating developmental precursors of later-emerging academic disabilities. Spina bifida myelomeningocele (SBM) is a neurodevelopmental disorder associated with particular problems in mathematics, in contrast to well-developed word reading. Children with SBM (n=30) and typically developing children (n=35) were used to determine whether cognitive abilities measured at 36 and 60 months of age mediated the effect of group on mathematical and reading achievement outcomes at 8.5 and 9.5 years of age. A series of multiple mediator models showed that: visual-spatial working memory at 36 months and phonological awareness at 60 months partially mediated the effect of group on math calculations, phonological awareness partially mediated the effect of group on small addition and subtraction problems on a test of math fluency, and visual-spatial working memory mediated the effect of group on a test of math problem solving. Groups did not differ on word reading, and phonological awareness was the only mediator for reading fluency and reading comprehension. The findings are discussed with reference to theories of mathematical development and disability and with respect to both common and differing cognitive correlates of math and reading.

Prediction and stability of mathematics skill and difficulty

The present study evaluated the stability of math learning difficulties over a 2-year period and investigated several factors that might influence this stability (categorical vs. continuous change, liberal vs. conservative cut point, broad vs. specific math assessment); the prediction of math performance over time and by performance level was also evaluated. Participants were 144 students initially identified as having a math difficulty (MD) or no learning difficulty according to low achievement criteria in the spring of Grade 3 or Grade 4. Students were reassessed 2 years later. For both measure types, a similar proportion of students changed whether assessed categorically or continuously. However, categorical change was heavily dependent on distance from the cut point and so more common for MD, who started closer to the cut point; reliable change index change was more similar across groups. There were few differences with regard to severity level of MD on continuous metrics or in terms of prediction. Final math performance on a broad computation measure was predicted by behavioral inattention and working memory while considering initial performance; for a specific fluency measure, working memory was not uniquely related, and behavioral inattention more variably related to final performance, again while considering initial performance.

Motor contingency learning and infants with Spina Bifida

Infants with Spina Bifida (SB) were compared to typically developing infants (TD) using a conjugate reinforcement paradigm at 6 months-of-age (n = 98) to evaluate learning, and retention of a sensory-motor contingency. Analyses evaluated infant arm-waving rates at baseline (wrist not tethered to mobile), during acquisition of the sensory-motor contingency (wrist tethered), and immediately after the acquisition phase and then after a delay (wrist not tethered), controlling for arm reaching ability, gestational age, and socioeconomic status. Although both groups responded to the contingency with increased arm-waving from baseline to acquisition, 15% to 29% fewer infants with SB than TD were found to learn the contingency depending on the criterion used to determine contingency learning. In addition, infants with SB who had learned the contingency had more difficulty retaining the contingency over time when sensory feedback was absent. The findings suggest that infants with SB do not learn motor contingencies as easily or at the same rate as TD infants, and are more likely to decrease motor responses when sensory feedback is absent. Results are discussed with reference to research on contingency learning in infants with and without neurodevelopmental disorders, and with reference to motor learning in school-age children with SB.

DNA-based species detection capabilities using laser transmission spectroscopy

Early detection of invasive species is critical for effective biocontrol to mitigate potential ecological and economic damage. Laser transmission spectroscopy (LTS) is a powerful solution offering real-time, DNA-based species detection in the field. LTS can measure the size, shape and number of nanoparticles in a solution and was used here to detect size shifts resulting from hybridization of the polymerase chain reaction product to nanoparticles functionalized with species-specific oligonucleotide probes or with the species-specific oligonucleotide probes alone. We carried out a series of DNA detection experiments using the invasive freshwater quagga mussel (Dreissena bugensis) to evaluate the capability of the LTS platform for invasive species detection. Specifically, we tested LTS sensitivity to (i) DNA concentrations of a single target species, (ii) the presence of a target species within a mixed sample of other closely related species, (iii) species-specific functionalized nanoparticles versus species-specific oligonucleotide probes alone, and (iv) amplified DNA fragments versus unamplified genomic DNA. We demonstrate that LTS is a highly sensitive technique for rapid target species detection, with detection limits in the picomolar range, capable of successful identification in multispecies samples containing target and non-target species DNA. These results indicate that the LTS DNA detection platform will be useful for field application of target species. Additionally, we find that LTS detection is effective with species-specific oligonucleotide tags alone or when they are attached to polystyrene nanobeads and with both amplified and unamplified DNA, indicating that the technique may also have versatility for broader applications.

Influence of unilateral castration and increased plane of nutrition on sexual development of Holstein bulls. III. Endocrine responses

Pituitary gonadotropic hormones were assayed in 65 Holstein bulls from 7 days to 16 months. Pituitary LH concentration and content at 2, 4, 8 and 16 months increased (P<.01) with age, while FSH content increased with age (P<.01) but was lower in UC bulls at 2, 4 and 8 months and higher at 16 months (A x UC, P<.01) as compared to intact bulls. In five samples of plasma collected at 90-minute intervals, one day each month from 1 to 15 months in 10 of the bulls killed at 16 months, LH concentration and variance changed (P<.01) with age reaching maxima at 4 and 3 months respectively. Plasma testosterone concentration and variance changed (P<.01) with age, reaching maxima at 10 and 9 months respectively. In the other 10 bulls killed at 16 months, assays of plasma collected before and after exposure to a teaser showed that stimulation increased LH by 20 minutes after exposure but LH declined by 60 minutes while testosterone was increased 20 (P<.05) and 60 (P<.01) minutes after exposure.

Influence of unilateral castration and increased plane of nutrition on sexual development of Holstein bulls. I. Growth and sperm production

Sixty-five Holstein bull calves were used to study the effects of unilateral castration (UC) and increased plane of nutrition on the growth and development of the reproductive system. Bulls were slaughtered at 1 wk., 2, 4, 8 and 16 months. Half of each slaughter group above one week was unilaterally castrated at 7 days of age. Half of the bulls remaining at 6 months of age received 90% of their recommended daily TDN allowance while the remainder received 120%. Compensatory hypertrophy was evident as early as 2 months and the degree of compensation increased for the duration of the experiment (Age x UC, P<.01). By 16 months of age the remaining testis of UC animals was 73% heavier than the average testis weight of intact bulls. While epididymal weight was significantly increased by UC, seminal vesicle weight was not. UC bulls produced significantly more sperm per testis than intact bulls both from the onset of puberty to slaughter and for the 16 week period prior to slaughter. Testis sperm concentration was similar in UC and intact bulls. UC at one weel of age caused greater testis growth and greater sperm production per testis, but did not promote earlier puberty.

The effects of pediatric traumatic brain injury on verbal and visual-spatial working memory

The purpose of this study was to investigate the effects of pediatric traumatic brain injury (TBI) on verbal and visual-spatial working memory (WM). WM tasks examined memory span through recall of the last item of a series of stimuli. Additionally, both verbal and visual-spatial tests had a dual-task condition assessing the effect of increasing demands on the central executive (CE). Inhibitory control processes in verbal WM were examined through intrusion errors. The TBI group (n = 73) performed more poorly on verbal and visual-spatial WM tasks than orthopedic-injured children (n = 30) and non-injured children (n = 40). All groups performed more poorly on the dual-task conditions, reflecting an effect of increasing CE load. This effect was not greater for the TBI group. There were no group differences in intrusion errors on the verbal WM task, suggesting that problems in WM experienced by children with TBI were not primarily due to difficulties in inhibitory control. Finally, injury-related characteristics, namely days to follow commands, accounted for significant variance in WM performance, after controlling for relevant demographic variables. Findings suggest that WM impairments in TBI are general rather than modality-specific and that severity indices measured over time are better predictors of WM performance than those taken at a single time point.

Effect of intracranial bleeds on the neurocognitive, academic, behavioural and adaptive functioning of boys with haemophilia

Brain insults are a risk factor for neuropsychological and academic deficits across several paediatric conditions. However, little is known about the specific effects of intracranial haemorrhage (ICH) in boys with haemophilia. The study compared neurocognitive, academic and socio-emotional/behavioural outcomes of boys with haemophilia with and without a history of ICH. Of 172 consecutive patients seen at a Pediatric Comprehensive Care Hemophila Centre, 18 had a history of ICH. Sixteen boys between the ages of 3 and 17 years were available for study and were matched to controls with haemophilia of the same age and disease severity and on the basis of maternal education. Groups were compared on neuropsychological and academic outcomes. Attention, socio-emotional function and executive skills were compared using data from parent questionnaires. Differences were found in intellectual function, visual-spatial skill, fine motor dexterity and particularly language-related skills, including vocabulary, word reading and applied math problem solving. Despite these group differences, outcomes were within the average range for most boys with ICH. No group differences were found in behavioural and socio-emotional functioning. Although ICH in haemophilia is not benign, it was not associated with significant cognitive and academic consequences for most boys. Early neuropsychological assessment may be indicated when there is a history of ICH. Investigation of age at ICH and quantitative measures of brain in relation to neurocognitive outcomes in larger groups of boys with ICH would be useful.

The cognitive phenotype of spina bifida meningomyelocele

A cognitive phenotype is a product of both assets and deficits that specifies what individuals with spina bifida meningomyelocele (SBM) can and cannot do and why they can or cannot do it. In this article, we review the cognitive phenotype of SBM and describe the processing assets and deficits that cut within and across content domains, sensory modality, and material, including studies from our laboratory and other investigations. We discuss some implications of the SBM cognitive phenotype for assessment, rehabilitation, and research.

The role of illustrations in children's inferential comprehension

Illustrations are a salient source of information in children's books, yet their effect on children's reading comprehension has been studied only through literal factual recall. The purpose of the current study was to determine the effect of illustrations on bridging inferences, an important aspect of meaning making in comprehension models. Identical short stories were presented under different illustration conditions with pictures that represented different parts of the story. Participants were 73 7- to 11-year-olds. Illustrations both facilitated and interfered with inferencing depending on the type of information depicted; however, this effect was reduced as grade increased. Additional findings were that the overall ability to make inferences increased with age and working memory was a significant predictor of this skill. Results are discussed in relation to cognitive and developmental models of comprehension.

Mathematical development in spina bifida

Spina bifida (SB) is a neural tube defect diagnosed before or at birth that is associated with a high incidence of math disability often without co-occurring difficulties in reading. SB provides an interesting population within which to examine the development of mathematical abilities and disability across the lifespan and in relation to the deficits in visual-spatial processing that are also associated with the disorder. An overview of math and its cognitive correlates in preschoolers, school-age children and adults with SB is presented including the findings from a longitudinal study linking early executive functions in infancy to the development of later preschool and school age math skills. These findings are discussed in relation to socio-historical perspectives on math education and implications for intervention and directions for further research are presented.

Hypothermia therapy after traumatic brain injury in children

BACKGROUND

Hypothermia therapy improves survival and the neurologic outcome in animal models of traumatic brain injury. However, the effect of hypothermia therapy on the neurologic outcome and mortality among children who have severe traumatic brain injury is unknown.

METHODS

In a multicenter, international trial, we randomly assigned children with severe traumatic brain injury to either hypothermia therapy (32.5 degrees C for 24 hours) initiated within 8 hours after injury or to normothermia (37.0 degrees C). The primary outcome was the proportion of children who had an unfavorable outcome (i.e., severe disability, persistent vegetative state, or death), as assessed on the basis of the Pediatric Cerebral Performance Category score at 6 months.

RESULTS

A total of 225 children were randomly assigned to the hypothermia group or the normothermia group; the mean temperatures achieved in the two groups were 33.1+/-1.2 degrees C and 36.9+/-0.5 degrees C, respectively. At 6 months, 31% of the patients in the hypothermia group, as compared with 22% of the patients in the normothermia group, had an unfavorable outcome (relative risk, 1.41; 95% confidence interval [CI], 0.89 to 2.22; P=0.14). There were 23 deaths (21%) in the hypothermia group and 14 deaths (12%) in the normothermia group (relative risk, 1.40; 95% CI, 0.90 to 2.27; P=0.06). There was more hypotension (P=0.047) and more vasoactive agents were administered (P<0.001) in the hypothermia group during the rewarming period than in the normothermia group. Lengths of stay in the intensive care unit and in the hospital and other adverse events were similar in the two groups.

CONCLUSIONS

In children with severe traumatic brain injury, hypothermia therapy that is initiated within 8 hours after injury and continued for 24 hours does not improve the neurologic outcome and may increase mortality. (Current Controlled Trials number, ISRCTN77393684 [controlled-trials.com].).

A model of comprehension in spina bifida meningomyelocele: meaning activation, integration, and revision

Spina bifida meningomyelocele (SBM) is a neurodevelopmental disorder associated with adequate development of word reading and single word comprehension, but deficient text and discourse comprehension. Studies of comprehension in children with SBM are reviewed in relation to a comprehension model in which meanings are either activated from the surface code or constructed through resource-intensive integration and revision processes to form representations of the text base and models of the situation described by the text. Two new studies probed the construction of situation models in SBM. Experiment 1 tested the ability to build spatial and affective situation models from single sentences in 86 children with SBM (8 to 18 years of age) and 37 control children (8 to 16 years of age). Experiment 2 tested the ability to integrate across sentences to build spatial situation models in 15 children with SBM and 15 age-matched controls. Compared to age peers, children with SBM did not construct situation models that required integration of information across sentences, even though they could construct such models from single sentences. The data bear on the distinctive SBM neurocognitive profile, and more generally, on the significance of integration processes for the constructive aspects of language comprehension.

Dopamine Antagonist Alters Serum Cortisol and Prolactin Secretion in Lactating Holstein Cows

The role of dopamine in regulating glucocorticoid and prolactin secretion was investigated in lactating Holstein cows by characterizing serum cortisol and prolactin responses to fluphenazine, a dopamine receptor antagonist. Twelve anovulatory cows received an intravenous bolus injection of either saline (n = 6) or 0.3 mg of fluphenazine/kg of body weight (n = 6) in wk 2 postpartum. Blood samples were collected every 30 min for 4 h before and 4 h after saline or fluphenazine injection. Serum progesterone concentration was 0.13 +/- 0.1 ng/mL and did not differ between groups. No difference in serum cortisol concentrations was detected between groups before treatments. Fluphenazine increased serum cortisol concentrations within 30 min after fluphenazine administration (>30 ng/mL) and concentrations remained elevated throughout the sampling period. Cortisol remained unchanged in saline-treated cows (<10 ng/mL). Prolactin concentrations also increased after fluphenazine administration (103.1 +/- 3.1 ng/mL), but were unaffected by saline (18 +/- 3.1 ng/mL). Prolactin concentrations remained elevated throughout the sampling period in fluphenazine-treated cows. Our results indicated that a dopamine antagonist increased cortisol, suggesting that endogenous dopamine, at least in part, regulates cortisol and prolactin secretion. These effects are regulated through dopamine receptors in anovulatory lactating dairy cows during the early postpartum period.

Arithmetic processing in children with spina bifida: Calculation accuracy, strategy use, and fact retrieval fluency

Three studies compared 98 children with spina bifida myelomeningocele (SBM)-a disorder associated with high rates of math disability and spatial deficits-to 94 typically developing children on multidigit subtraction and cognitive addition tasks. Children with SBM were classified into those with reading decoding and math disability, only math disability, and no reading or math disability. Study 1 showed that visual-spatial errors in multidigit arithmetic were not elevated in children with SBM. In Study 2, deficits in accuracy, speed, and strategy-use in single-digit addition characterized groups with math disability regardless of reading status. Accuracy and speed on single-digit addition was strongly related to performance on multidigit subtraction. A math-level matching design in Study 3 revealed less mastery of math facts by the group with SBM. The results are discussed with reference to cognitive and neuropsychological models of math disability.

Meaning construction and integration in children with hydrocephalus

Text comprehension processes were investigated in children with hydrocephalus, a neurodevelopmental disorder associated with good word decoding, but deficient reading comprehension. In Experiment 1, hydrocephalus and control groups were similar in processes related to activating word meanings and using context to enhance meaning. The hydrocephalus group was poorer at suppressing contextually irrelevant meanings. In Experiment 2, the hydrocephalus group had difficulty integrating information from an earlier read sentence to understand a new sentence as textual distance between the two propositions increased, suggesting difficulty in reactivation processes related to comprehension. Results are discussed in relation to cognitive and neurocognitive models of comprehension.

Effect of intracranial bleeds on the health and quality of life of boys with hemophilia

OBJECTIVES

To compare the health, physical function, and quality of life (QoL) of boys with hemophilia with and without a history of intracranial hemorrhage (ICH).

STUDY DESIGN

Of 172 patients with hemophilia A or B, 18 (10%) had at least one episode of ICH. For outcome assessments, 16 of 18 (89%) boys with ICH and 32 controls, matched (1:2) for age and severity of hemophilia, were available. The outcome measures were neurologic function, physical function, and QoL.

RESULTS

The median age of the boys at the first ICH was 5.9 months (range, 1 day to 2.7 years). Boys with ICH had a higher incidence of inhibitors and lower mean household income. Neurologic examination was abnormal in seven of 16 (44%) boys with ICH and nine of 32 (28%) controls (P=.3). The mean physical function in boys with ICH was lower (82%+/-25%) compared with controls (93.5%+/-12%, P=.045). The QoL was decreased in boys with ICH compared with controls (6.8+/-3.2 vs 8.5+/-1.4, P=.02), whereas health-related QoL was not significantly different between groups.

CONCLUSION

The poorer long-term outcomes of boys with hemophilia appropriately treated for ICH, especially in the domain of QoL, suggest that new strategies to prevent ICH and to manage ICH effectively in this population are needed.