Early Indicators of Academic Difficulties in Children with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a genetic neurocutaneous disorder, with an estimated incidence of 1 in 3,000 persons. It is phenotypically variable disorder associated with elevated rates of intellectual disability and learning disabilities, attention problems, speech and language impairment, and executive functioning deficits. Research investigating the presentation of NF1 in preschool-age children is limited, but the data available indicate that cognitive difficulties are present and can be identified at an early age. There is also evidence from the general population that early neuropsychological deficits can be used to predict concurrent and later learning difficulties. The goal of the current study was to characterize the early learning profile of young children with NF1 and to determine which neuropsychological skills may contribute to academic difficulties. The results indicate that early learning difficulties are present and can be identified in young children with NF1. General intellectual functioning was strongly related to academic performance and accounted for many of the relations between neuropsychological and academic skills in the NF1 group. However, some specific neuropsychological skills continued to relate to foundational reading and math skills even when controlling for overall developmental level. These findings provide an indication of processing domains that may support academic skill development for future longitudinal work. Clinically, the findings suggest that cognitive screenings should be a routine part of care for young children with NF1. If appropriate interventions are implemented at an early age, academic skill development could be altered, preventing subtle learning difficulties from becoming more pronounced over time

Memory in autism spectrum disorder: a meta-analysis of experimental studies

To address inconsistencies in the literature on memory in Autism Spectrum Disorder (ASD), we report the first ever meta-analysis of short-term (STM) and episodic long-term (LTM) memory in ASD, evaluating the effects of type of material, type of retrieval and the role of inter-item relations. Analysis of 64 studies comparing individuals with ASD and typical development (TD) showed greater difficulties in ASD compared to TD individuals in STM (Hedges’ g=-0.53 [95%CI -0.90; -0.16], p=.005, I²=96%) compared to LTM (g=-0.30 [95%CI -0.42; -0.17], p<.00001, I²=24%), a small difficulty in verbal LTM (g=-0.21, p=.01), contrasting with a medium difficulty for visual LTM (g= -0.41, p=.0002) in ASD compared to TD individuals. We also found a general diminution in free recall compared to cued recall and recognition (LTM, free recall: g=-0.38, p<.00001, cued recall: g=-0.08, p=.58, recognition: g=-0.15, p=.16; STM, free recall: g=-0.59, p=.004, recognition: g=-0.33, p=.07). We discuss these results in terms of their relation to semantic memory. The limited diminution in verbal LTM and preserved overall recognition and cued recall (supported retrieval) may result from a greater overlap of these tasks with semantic long-term representations which are overall preserved in ASD. By contrast, difficulties in STM or free recall may result from less overlap with the semantic system or may involve additional cognitive operations and executive demands. These findings highlight the need to support STM functioning in ASD and acknowledge the potential benefit of using verbal materials at encoding and broader forms of memory support at retrieval to enhance performance

Mathematics difficulties in extremely preterm children : evidence of a specific deficit in basic mathematics processing

Background: Extremely preterm (EP, <26 wk gestation) children have been observed to have poor academic achievement in comparison to their term-born peers, especially in mathematics. This study investigated potential underlying causes of this difficulty. Methods: A total of 219 EP participants were compared with 153 term-born control children at 11 y of age. All children were assessed by a psychologist on a battery of standardized cognitive tests and a number estimation test assessing children’s numerical representations. Results: EP children underperformed in all tests in comparison with the term controls (the majority of Ps < 0.001). Different underlying relationships between performance on the number estimation test and mathematical achievement were found in EP as compared with control children. That is, even after controlling for cognitive ability, a relationship between number representations and mathematical performance persisted for EP children only (EP: r = 0.346, n = 186, P < 0.001; control: r = 0.095, n = 146, P = 0.256). Conclusion: Interventions for EP children may target improving children’s numerical representations in order to subsequently remediate their mathematical skills

Working Memory, Language, Reading and Behavior: The Importance of Laterality, Symbolism and Default Networks

The present review draws attention to the importance of working memory, not just for cognitive development, but also for language-related reading skills. The classical work of Patricia Goldman-Rakic drew attention to the advent of language in human development in allowing the efficient use of symbolic ‘goals’ to be held in working memory throughout the processes of goal achievement (sometimes over long periods of time). The role of a switching mechanism between cognitive, language and default circuits allows the recruitment of salient emotional and/or memory information during the process of goal completion. When these systems malfunction, the often-described comorbidities between conditions such as ADHD, language and learning disability, and behavior problems may be observed. At a developmental level, the capacity for symbolic representation in working memory is likely to be important for early orthographic and later comprehension in reading ability. More recent work has drawn attention to a specific role for selective cerebellar working memory selective areas such as lobules V11b/V111a in supporting parallel cortico-cerebellar visual working memory networks, a new specific role for cerebellar/cortical connections

Intelligence and specific cognitive functions in intellectual disability: implications for assessment and classification

Purpose of review: Current diagnostic criteria for intellectual disability categorize ability as measured by IQ tests. However, this does not suit the new conceptualization of intellectual disability, which refers to a range of neuropsychiatric syndromes that have in common early onset, cognitive impairments, and consequent deficits in learning and adaptive functioning. A literature review was undertaken on the concept of intelligence and whether it encompasses a range of specific cognitive functions to solve problems, which might be better reported as a profile, instead of an IQ, with implications for diagnosis and classification of intellectual disability. Recent findings: Data support a model of intelligence consisting of distinct but related processes. Persons with intellectual disability with the same IQ level have different cognitive profiles, based on varying factors involved in aetiopathogenesis. Limitations of functioning and many biopsychological factors associated with intellectual disability are more highly correlated with impairments of specific cognitive functions than with overall IQ. Summary: The current model of intelligence, based on IQ, is of limited utility for intellectual disability, given the wide range and variability of cognitive functions and adaptive capacities. Assessing level of individual impairment in executive and specific cognitive functions may be a more useful alternative. This has considerable implications for the revision of the International Classification of Diseases and for the cultural attitude towards intellectual disability in general

Visual illusions: An interesting tool to investigate developmental dyslexia and autism spectrum disorder

A visual illusion refers to a percept that is different in some aspect from the physical stimulus. Illusions are a powerful non-invasive tool for understanding the neurobiology of vision, telling us, indirectly, how the brain processes visual stimuli. There are some neurodevelopmental disorders characterized by visual deficits. Surprisingly, just a few studies investigated illusory perception in clinical populations. Our aim is to review the literature supporting a possible role for visual illusions in helping us understand the visual deficits in developmental dyslexia and autism spectrum disorder. Future studies could develop new tools – based on visual illusions – to identify an early risk for neurodevelopmental disorders

Number Processing in Infants and Children Born Very Preterm

Individuals born very preterm (<32 weeks; VP) have notably poorer attainment in mathematics than their term-born peers. Only a handful of studies have investigated basic numerical skills in VP children and the underlying mechanisms associated with problems with mathematics in this population are still not fully comprehended. Basic processes underlying numerical cognition can go awry very early in development and there is a lack of knowledge of early trajectories of acquisition of numerical skills in infants born prematurely. This thesis reports on a series of studies investigating number processing in very preterm infants and children. These make use of a combination of tools, such as neurodevelopmental assessments, eye-tracking, event-related-potentials, neuropsychological evaluations and experimental tasks. Specifically, cross-sectional studies investigated numerical sensitivity in VP infants aged six and twelve months. Behavioural and electrophysiological measures assessing a range of domain-general and domain-specific skills associated with mathematics performance were also investigated in VP school-aged children. The results showed that, during the first year of post-natal life, VP infants do not exhibit differential developmental trajectories in the basic ability to discriminate numerosities compared to infants born at full term, although they required a longer time to discriminate the new number of elements. Later in development, school-aged VP children demonstrated difficulties in processing basic numerical information. Electrophysiological data demonstrated that this might be associated with deficits in sensory and attention resources and not necessarily in how VP children encode number-related information. Difficulties in processing numerical information, however, have only a marginal impact on their performance in mathematics. We tentatively conclude that difficulties in mathematics in individuals born very prematurely are largely associated with domain-general skills

Neuropsychological Assessment of Children with Learning Disabilities

Learning disabilities are a heterogeneous and common group of disorders that have a relevant impact on children’s academic function. The most common learning disorders consist of dyslexia, dyscalculia, dysgraphia or other non-verbal learning disorders. These disorders are commonly associated with neurological or behavioral disorders such as attention-deficit hyperactivity disorders. Understanding of cognitive and mental problems of children with learning disorders is an interesting challenge, and various approaches have been applied for their study, including medical, genetic, educational, epidemiologic and experimental psychologist. Nowadays, clinical neuropsychological approach, which is based on neurocognitive models, is one of the best existing models for description and interpretation of learning disorders. This approach assumes that there is a strong relationship between the various learning deficits and brain functioning. This paper consists of a descriptive review about components of a specialized neuropsychological approach that can be applied for the assessment of children with learning disabilities