A comparison of children with epilepsy to an age- and IQ-matched control group on the Children's Memory Scale.

Past research has found that children with epilepsy exhibit decreased memory skills. In addition, some studies have found that children with epilepsy obtain significantly lower IQ scores than controls. In an effort to examine whether children with epilepsy have specific memory weaknesses versus global cognitive difficulties, the present study compared the performance of 62 children (age range = 6-16 years). Thirty-one children with epilepsy were compared to 31 age- and IQ-matched controls on the Children's Memory Scale (CMS) to determine whether differences in memory skills persist when IQ is matched. An independent t-test comparing index and scaled scores was performed. The results indicated that with the exception of the Word Pairs subtest (p < .01), children with epilepsy did not differ significantly on the CMS subtests when IQ was matched. This suggests that list-learning paradigms may be particularly sensitive to memory impairments in children with epilepsy and/or that children with epilepsy have more global cognitive impairments.     

Neurocognitive functioning of preschool children with uncomplicated epilepsy

Only few studies are available on the cognitive functioning of preschool children with uncomplicated epilepsy. The aim of this study was to describe the neurocognitive functioning of 3–6-year-old children with uncomplicated epilepsy. A subgroup of children with uncomplicated epilepsy from a population based cohort of preschool children with active epilepsy (N = 64) participated in the study. The neurocognitive functioning of these children (N = 13) was compared to that of matched healthy controls (N = 13). The Wechsler's Primary and Preschool Scale of Intelligence - Revised and the Developmental Neuropsychological Assessment were administered. The intellectual functioning of the children with uncomplicated epilepsy was within normal range, but differed significantly from that of healthy controls, which was contrary to expectations. Statistically significant differences emerged between the study and the control group in Verbal IQ and Full Scale IQ, but no differences were found in Performance IQ. The children with uncomplicated epilepsy also had minor neurocognitive difficulties in verbal short-term memory (p <.01) compared to healthy children. The result suggests that uncomplicated epilepsy in preschool children may interfere with language and verbal short-term memory functions. Further studies with detailed neuropsychological assessments and follow-up time are needed to gain more insight into the developmental course of children with uncomplicated epilepsy. Also, because of the developmental risks reported in this study, psychological screening and detailed neuropsychological assessment are recommended in clinical practice.     

Facial memory deficits in children with fetal alcohol spectrum disorders

Prenatal exposure to alcohol may lead to a range of neurobehavioral effects, including impaired learning and memory. Although children with fetal alcohol spectrum disorders (FASD) exhibit both verbal and nonverbal memory impairments, their memory for faces has not been as thoroughly investigated and the extent literature provides inconsistent results. The aim of the current study was to determine whether difficulties in face memory exist in children with FASD and whether the difficulties are mediated by task demands. To address this, we used two measures of immediate and delayed facial recognition memory, the Children's Memory Scale (CMS) and Test of Memory and Learning (TOMAL). Compared to typically developing controls, children with FASD showed memory deficits on all tests and were more likely to perform in a clinically significant range. As well, children performed more poorly on the CMS compared to TOMAL, a finding consistent with the greater difficulty of the CMS task. Our results are consistent with our hypothesis that children with FASD show impairment in facial memory, particularly on demanding memory tasks.     

Facial memory deficits in children with fetal alcohol spectrum disorders

Prenatal exposure to alcohol may lead to a range of neurobehavioral effects, including impaired learning and memory. Although children with fetal alcohol spectrum disorders (FASD) exhibit both verbal and nonverbal memory impairments, their memory for faces has not been as thoroughly investigated and the extent literature provides inconsistent results. The aim of the current study was to determine whether difficulties in face memory exist in children with FASD and whether the difficulties are mediated by task demands. To address this, we used two measures of immediate and delayed facial recognition memory, the Children's Memory Scale (CMS) and Test of Memory and Learning (TOMAL). Compared to typically developing controls, children with FASD showed memory deficits on all tests and were more likely to perform in a clinically significant range. As well, children performed more poorly on the CMS compared to TOMAL, a finding consistent with the greater difficulty of the CMS task. Our results are consistent with our hypothesis that children with FASD show impairment in facial memory, particularly on demanding memory tasks.     

Individual and developmental differences in eyewitness recall and suggestibility in children with intellectual disabilities

This study examined two key issues: (1) whether there were developmental improvements in eyewitness memory performance for children with intellectual disabilities (ID); and (2) whether standardised measures of cognitive ability and suggestibility would relate to eyewitness recall and suggestibility. Children with ID and age‐matched controls (ages 8/9 and 12 years) watched a video of a crime and were asked a range of open‐ended and specific questions about the event in a subsequent interview. Free recall increased between the two age levels for children with and without ID, but at a faster rate for those without ID. For other question types, differences in performance between children with and without ID were far more marked than age differences. Standardised measures of interrogative suggestibility (Gudjonsson Suggestibility Scale, GSS), verbal IQ, non‐verbal IQ, mental age and speed of information processing were related to eyewitness performance. In particular, higher eyewitness recall scores (free recall, non‐leading specific questions) were related to higher scores on the standardised GSS free recall measure; and higher eyewitness suggestibility scores were related to higher scores on the standardised GSS suggestibility measures. Mental age was a better predictor of performance on a range of eyewitness memory question types than verbal or non‐verbal IQ; and speed of information processing showed some relationships with eyewitness performance. Copyright © 2006 John Wiley & Sons, Ltd.     

Reading Comprehension in Children with ADHD: Cognitive Underpinnings of the Centrality Deficit

We examined reading comprehension in children with ADHD by assessing their ability to build a coherent mental representation that allows them to recall central and peripheral information. We compared children with ADHD (mean age 9.78) to word reading-matched controls (mean age 9.89) on their ability to retell a passage. We found that even though children with ADHD recalled more central than peripheral information, they showed their greatest deficit, relative to controls, on central information—a centrality deficit (Miller and Keenan, Annals of Dyslexia 59:99–113, 2009). We explored the cognitive underpinnings of this deficit using regressions to compare how well cognitive factors (working memory, inhibition, processing speed, and IQ) predicted the ability to recall central information, after controlling for word reading ability, and whether these cognitive factors interacted with ADHD symptoms. Working memory accounted for the most unique variance. Although previous evidence for reading comprehension difficulties in children with ADHD have been mixed, this study suggests that even when word reading ability is controlled, children with ADHD have difficulty building a coherent mental representation, and this difficulty is likely related to deficits in working memory.     

Working memory deficits can be overcome: Impacts of training and medication on working memory in children with ADHD

This study evaluated the impact of two interventions—a training program and stimulant medication—on working memory (WM) function in children with attention deficit hyperactivity disorder (ADHD). Twenty‐five children aged between 8 and 11 years participated in training that taxed WM skills to the limit for a minimum of 20 days, and completed other assessments of WM and IQ before and after training, and with and without prescribed drug treatment. While medication significantly improved visuo‐spatial memory performance, training led to substantial gains in all components of WM across untrained tasks. Training gains associated with the central executive persisted over a 6‐month period. IQ scores were unaffected by either intervention. These findings indicate that the WM impairments in children with ADHD can be differentially ameliorated by training and by stimulant medication. Copyright © 2009 John Wiley & Sons, Ltd.     

Adaptive training leads to sustained enhancement of poor working memory in children

Working memory plays a crucial role in supporting learning, with poor progress in reading and mathematics characterizing children with low memory skills. This study investigated whether these problems can be overcome by a training program designed to boost working memory. Children with low working memory skills were assessed on measures of working memory, IQ and academic attainment before and after training on either adaptive or non‐adaptive versions of the program. Adaptive training that taxed working memory to its limits was associated with substantial and sustained gains in working memory, with age‐appropriate levels achieved by the majority of children. Mathematical ability also improved significantly 6 months following adaptive training. These findings indicate that common impairments in working memory and associated learning difficulties may be overcome with this behavioral treatment.     

Identifying the nature of impairments in executive functioning and working memory of children with severe difficulties in arithmetic

An age-matched achievement-matched design was used to examine whether the executive functioning and working memory impairments exhibited by children with severe difficulties in arithmetic (SDA) are better viewed as developmental lags or as cognitive deficits. Three groups of children were included: 20 SDA children, 20 typically achieving children (CM) matched in chronological age with the SDA children, and 20 younger typically achieving children (AM) matched in achievement with the SDA group. While children with SDA did not exhibit impairments in color-word inhibition and verbal working memory, they did demonstrate impairments in shifting, quantity-digits inhibition, and visuospatial working memory. As children with SDA did not perform more poorly than their AM counterparts on any of these tasks, impairments in specific areas of executive functioning and working memory appear to reflect developmental lags rather than cognitive deficits.     

Differences in memory functioning between children with attention-deficit/hyperactivity disorder and/or focal epilepsy

Prior research has shown that attention-deficit/hyperactivity disorder (ADHD) and epilepsy are frequently comorbid and that both disorders are associated with various attention and memory problems. Nonetheless, limited research has been conducted comparing the two disorders in one sample to determine unique versus shared deficits. Hence, we investigated differences in working memory (WM) and short-term and delayed recall between children with ADHD, focal epilepsy of mixed foci, comorbid ADHD/epilepsy and controls. Participants were compared on the Core subtests and the Picture Locations subtest of the Children’s Memory Scale (CMS). Results indicated that children with ADHD displayed intact verbal WM and long-term memory (LTM), as well as intact performance on most aspects of short-term memory (STM). They performed worse than controls on Numbers Forward and Picture Locations, suggesting problems with focused attention and simple span for visual-spatial material. Conversely, children with epilepsy displayed poor focused attention and STM regardless of the modality assessed, which affected encoding into LTM. The only loss over time was found for passages (Stories). WM was intact. Children with comorbid ADHD/epilepsy displayed focused attention and STM/LTM problems consistent with both disorders, having the lowest scores across the four groups. Hence, focused attention and visual-spatial span appear to be affected in both disorders, whereas additional STM/encoding problems are specific to epilepsy. Children with comorbid ADHD/epilepsy have deficits consistent with both disorders, with slight additive effects. This study suggests that attention and memory testing should be a regular part of the evaluation of children with epilepsy and ADHD.     

Neurodevelopmental model of long-term outcomes of adult survivors of childhood brain tumors

Childhood brain tumors and related treatments disrupt the developing brain and have a cascading impact on core cognitive skills and intellectual (intelligence quotient [IQ]) and academic achievement outcomes. Theoretical models for this cascade have been developed based on the literature, but no studies thus far have empirically evaluated the models. The current study aimed to empirically test the two extant models and generate a new data-driven model of the relationships among neurodevelopmental risk factors, core cognitive skills (i.e., processing speed, attention span, working memory), and IQ and achievement outcomes. Fifty-seven adult survivors of childhood brain tumors and fifty-seven demographically matched neurotypical individuals were included in the current study. The average age at brain tumor diagnosis was 8 years, and the average time since diagnosis was 17 years. Three a priori path models tested the hypothesized relationships among variables. Results of the path analyses revealed that the hybrid model best fit the data for both survivors and controls based on all statistical criteria. For survivors, processing speed was the core cognitive skill most widely associated with neurodevelopmental risk factors and outcomes. However, working memory and attention span also had unique contributions to IQ and academic achievement. Processing speed appears to be the central cognitive skill that disrupts the other core cognitive skills of attention span and working memory, and all three make a unique contribution to IQ and academic achievement. This is best demonstrated by a novel neurodevelopmental model that combines components of two earlier untested theoretical models.     

Assessment of the global intelligence and selective cognitive capacities in preterm 8-year-old children

The aim of this study was to assess various cognitive abilities such as attention, IQ, reasoning, and memory related to academic achievement in 8- and 9-year-old preterm children. A total of 141 children were assessed. The preterm group (=37 weeks) comprised 63 children and was compared to 78 full-term children. Attention was evaluated using the d2 Selective Attention test, and the IQ by the L-M form of the Stanford-Binet Intelligence Scale, establishing a profile of abilities: perception, memory, comprehension, reasoning, and verbal fluency. Significant differences in IQ were found between the preterm and full-term children. Of the cognitive abilities assessed, the only significant differences were found in verbal fluency, with preterm boys showing lower verbal fluency scores than full-term children. In conclusion, all preterm groups have attention ability similar to that of full-term children. However, preterm children obtain lower scores in intelligence measures. In addition, preterm boys have verbal fluency difficulties. Taking into account the increase in preterm births, suitable intervention programs must be planned to attend the difficulties found.     

Executive Functions in Preschool Children with Aggressive Behavior: Impairments in Inhibitory Control

The question whether executive function (EF) deficits in children are associated with conduct problems remains controversial. Although the origins of aggressive behavior are to be found in early childhood, findings from EF studies in preschool children with aggressive behavior are inconsistent. The current study aimed to investigate whether preschool children with aggressive behavior show impairments in EF. From a population-based sample, 82 preschool children who were showing aggressive behavior as indicated by scores at or above the 93rd percentile on the Aggressive Behavior Scale of the CBCL 1 1/2-5 were selected. These children with aggressive behavior were matched on IQ to a group of typically developing control children (N = 99). Six neuropsychological tasks were administered to assess set shifting, inhibition, working memory and verbal fluency. A factor analysis was conducted which yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition factor than control children and boys performed worse on this factor than girls. This association between aggressive behavior and inhibition deficits was maintained after controlling for attention problems. In addition, gender differences in all EFs measured were found with boys exhibiting more impairment in EF than girls. These findings demonstrate that preschool children with aggressive behavior show impairments in inhibition, irrespective of attention problems.     

Working memory, reading, and mathematical skills in children with developmental coordination disorder

The aim of the present study was investigate the relationship between working memory and reading and mathematical skills in 55 children diagnosed with developmental coordination disorder (DCD). The findings indicate a pervasive memory deficit in all memory measures. In particular, deficits observed in visuospatial short-term and working memory tasks were significantly worse than in the verbal short-term memory ones. On the basis of these deficits, the sample was divided into high and low visuospatial memory ability groups. The low visuospatial memory group performed significantly worse on the attainment measures compared to the high visuospatial memory group, even when the contribution of IQ was taken into account. When the sample was divided into high and low verbal working memory ability groups, verbal working memory skills made a unique contribution to attainment only when verbal IQ was taken into account, but not when performance IQ was statistically controlled. It is possible that the processing demands of the working memory tasks together with the active motor component reflected in the visuospatial memory tasks and performance IQ subtest both play a crucial role in learning in children with DCD.     

Speech‐evoked auditory brainstem responses reflect familial and cognitive influences

Cortical function and related cognitive, language, and communication skills are genetically influenced. The auditory brainstem response to speech is linked to language skill, reading ability, cognitive skills, and speech‐in‐noise perception; however, the impact of shared genetic and environmental factors on the response has not been investigated. We assessed auditory brainstem responses to speech presented in quiet and background noise from (1) 23 pairs of same sex, same learning diagnosis siblings (Siblings), (2) 23 unrelated children matched on age, sex, IQ, and reading ability to one of the siblings (Reading‐Matched), and (3) 22 pairs of unrelated children matched on age and sex but not on reading ability to the same sibling (Age/Sex‐Matched). By quantifying response similarity as the intersubject response‐to‐response correlation for sibling pairs, reading‐matched pairs, and age‐ and sex‐matched pairs, we found that siblings had more similar responses than age‐ and sex‐matched pairs and reading‐matched pairs. Similarity of responses between siblings was as high as the similarity of responses collected from an individual over the course of the recording session. Responses from unrelated children matched on reading were more similar than responses from unrelated children matched only on age and sex, supporting previous data linking variations in auditory brainstem activity with variations in reading ability. These results suggest that auditory brainstem function can be influenced by siblingship and auditory‐based communication skills such as reading, motivating the use of speech‐evoked auditory brainstem responses for assessing risk of reading and communication impairments in family members.     

Numerical and arithmetical cognition: patterns of functions and deficits in children at risk for a mathematical disability.

Based on performance on standard achievement tests, first-grade children (mean age = 82 months) with IQ scores in the low-average to high-average range were classified as at risk for a learning disability (LD) in mathematics, reading, or both. These at-risk children (n = 55) and a control group of academically normal peers (n = 35) were administered experimental tasks that assessed number comprehension and production skills, counting knowledge, arithmetic skills, working memory, and ease of retrieving information from long-term memory. Different patterns of intact cognitive functions and deficits were found for children in the different at-risk groups. As a set, performance on the experimental tasks accounted for roughly 50% and 10% of the group differences in mathematics and reading achievement, respectively, above and beyond the influence of IQ. Performance on the experimental tasks thus provides insights into the cognitive deficits underlying different forms of LD, as well as into the sources of individual differences in academic achievement.     

Intelligence: new findings and theoretical developments

We review new findings and new theoretical developments in the field of intelligence. New findings include the following: (a) Heritability of IQ varies significantly by social class. (b) Almost no genetic polymorphisms have been discovered that are consistently associated with variation in IQ in the normal range. (c) Much has been learned about the biological underpinnings of intelligence. (d) "Crystallized" and "fluid" IQ are quite different aspects of intelligence at both the behavioral and biological levels. (e) The importance of the environment for IQ is established by the 12-point to 18-point increase in IQ when children are adopted from working-class to middle-class homes. (f) Even when improvements in IQ produced by the most effective early childhood interventions fail to persist, there can be very marked effects on academic achievement and life outcomes. (g) In most developed countries studied, gains on IQ tests have continued, and they are beginning in the developing world. (h) Sex differences in aspects of intelligence are due partly to identifiable biological factors and partly to socialization factors. (i) The IQ gap between Blacks and Whites has been reduced by 0.33 SD in recent years. We report theorizing concerning (a) the relationship between working memory and intelligence, (b) the apparent contradiction between strong heritability effects on IQ and strong secular effects on IQ, (c) whether a general intelligence factor could arise from initially largely independent cognitive skills, (d) the relation between self-regulation and cognitive skills, and (e) the effects of stress on intelligence.     

A comparison of working memory profiles in children with ADHD and DCD

The main objective of present study was to investigate whether the patterns of working memory performance differ as a function of attention and motor difficulties, and whether children with ADHD and DCD could be reliably discriminated on the basis of their memory deficits. A related aim was to investigate the link between their working memory profiles and academic attainment. Fifty children with ADHD-Combined, 55 children with DCD, and an age-matched group of 50 typically developing children with average working memory were assessed on standardized measures of working memory, IQ, and academic attainment (reading, spelling, comprehension, and math). The normal controls performed significantly better than both clinical groups on all working memory tests. Specific patterns emerged in the memory profile of the clinical groups: The children with DCD had a depressed performance in all working memory tests, with particularly low scores in visuospatial memory tasks; children with ADHD performed within age-expected levels in short-term memory but had a pervasive working memory deficit that impacted both verbal and visuospatial domains. The clinical groups could reliably be discriminated on the basis of their short-term memory scores. Their learning profiles were similar. It is possible that the working memory profiles of the children with ADHD and DCD are influenced by distinct underlying cognitive mechanisms, rather than a general neurodevelopmental delay. Despite these distinctive patterns of memory performance, both clinical groups performed similarly on academic attainments, suggesting that memory may underlie learning difficulties, independent of related clinical disorders.     

Neuropsychological functioning in preschool-age children with sickle cell disease: the role of illness-related and psychosocial factors.

Cognitive and academic deficits have been identified in school-aged children with sickle cell disease (SCD). However, there have been very few identified studies that examine neuropsychological functioning in preschool-age children with SCD. It is important to understand effects of SCD from a developmental perspective and to consider the contribution of environmental factors in this at-risk population. Neuropsychological functioning of preschool-age children with SCD and no history of overt stroke (n = 26) was examined across several domains (language, immediate memory/brief attention, visuospatial/visuoconstructional, motor/visuomotor). The mean Full Scale IQ for the sample was 89.0. Performance on the Immediate Memory/ Brief Attention domain was significantly higher than the other domains, although the pattern of performance was relatively consistent, with mean standard scores ranging from 88.0 to 95.0. Disease severity was not significantly related to cognitive functioning in this group of young children with SCD. Socioeconomic status (SES) was significantly correlated with most domain scores and, based on regression analyses, accounted for 18% to 47% of the variance in functioning. Psychosocial factors, such as number of children living in the home and parental stress levels, were negatively associated with Motor/Visuomotor skills, and weekly hours in school/day care was positively associated with language-related skills. Results suggest that, at this young age, psychosocial risk factors appear to be appropriate targets for intervention, with the goal of improving long-term outcome in children with SCD. Further investigations should include comparison to a matched control group.     

Neuropsychological Functioning in Preschool-age Children with Sickle Cell Disease: The Role of Illness-related and Psychosocial Factors

Cognitive and academic deficits have been identified in school-aged children with sickle cell disease (SCD). However, there have been very few identified studies that examine neuropsychological functioning in preschool-age children with SCD. It is important to understand effects of SCD from a developmental perspective and to consider the contribution of environmental factors in this at-risk population. Neuropsychological functioning of preschool-age children with SCD and no history of overt stroke (n = 26) was examined across several domains (language, immediate memory/brief attention, visuospatial/visuoconstructional, motor/visuomotor). The mean Full Scale IQ for the sample was 89.0. Performance on the Immediate Memory/ Brief Attention domain was significantly higher than the other domains, although the pattern of performance was relatively consistent, with mean standard scores ranging from 88.0 to 95.0. Disease severity was not significantly related to cognitive functioning in this group of young children with SCD. Socioeconomic status (SES) was significantly correlated with most domain scores and, based on regression analyses, accounted for 18% to 47% of the variance in functioning. Psychosocial factors, such as number of children living in the home and parental stress levels, were negatively associated with Motor/Visuomotor skills, and weekly hours in school/day care was positively associated with language-related skills. Results suggest that, at this young age, psychosocial risk factors appear to be appropriate targets for intervention, with the goal of improving long-term outcome in children with SCD. Further investigations should include comparison to a matched control group.