How neuropsychology informs our understanding of developmental disorders

Motor Adaptation Deficits in Children with Developmental Coordination Disorder and/or Reading Disorder

Procedural learning has been mainly tested through motor sequence learning tasks in children with neurodevelopmental disorders, especially with isolated Developmental Coordination Disorder (DCD) and Reading Disorder (RD). Studies on motor adaptation are scarcer and more controversial. This study aimed to compare the performance of children with isolated and associated DCD and RD in a graphomotor adaptation task. In total, 23 children with RD, 16 children with DCD, 19 children with DCD-RD, and 21 typically developing (TD) children wrote trigrams both in the conventional (from left to right) and opposite (from right to left) writing directions. The results show that movement speed and accuracy were more impacted by the adaptation condition (opposite writing direction) in children with neurodevelopmental disorders than TD children. Our results also reveal that children with RD have less difficulty adapting their movement than children with DCD. Children with DCD-RD had the most difficulty, and analysis of their performance suggests a cumulative effect of the two neurodevelopmental disorders in motor adaptation.

Profiling Children With Cerebral Visual Impairment Using Multiple Methods of Assessment to Aid in Differential Diagnosis

Cerebral (cortical) visual impairment (CVI), the primary cause of visual impairment in children in high-income countries, is increasing globally due to improved life-saving measures for premature and full-term infants. Yet the consequences of this condition are only beginning to be understood and addressed. According to the topography, site, and the extent of the pathology, the deficit may variably concern central visual functions, visual field, perception of movement, visual analysis, visual exploration, attention, or visual memory, as well as visual guidance of movement. Each affected child has a unique clinical picture, which needs to be identified and individually profiled. This is probably the underlying reason that CVI is commonly underdiagnosed or misdiagnosed, especially in children, and, as a consequence, the full range of potential behavioral outcomes are not identified and adequately addressed. The present paper shows how the use of multiple methods of assessment can improve understanding of children with CVI.

I can read it in your eyes: what eye movements tell us about visuo-attentional processes in developmental dyslexia

Most studies today agree about the link between visual-attention and oculomotor control during reading: attention seems to affect saccadic programming, that is, the position where the eyes land in a word. Moreover, recent studies show that visuo-attentional processes are strictly linked to normal and impaired reading. In particular, a large body of research has found evidence of defective visuo-attentional processes in dyslexics. What do eye movements tell us about visuo-attentional deficits in developmental dyslexia? The purpose of this paper is to explore the link between oculomotor control and dyslexia, taking into account its heterogeneous manifestation and comorbidity. Clinical perspectives in the use of the eye-movements approach to better explore and understand reading impairments are discussed.

Development, cognition, and behaviour in Pitt-Hopkins syndrome

AIM

The aim of the study was to collect detailed data on behavioural, adaptive, and psychological functioning in 10 individuals with Pitt-Hopkins syndrome (PTHS), with specific attention to manifestations of autism spectrum disorder (ASD).

METHOD

The participants (four females, six males), residing in the Netherlands and Belgium, were ascertained through the Dutch national PTHS support group. Median age of participants was 10 years, the age range was between 32 and 289 months. They underwent psychiatric examinations and neuropsychological measurements using a comprehensive assessment battery. Additionally, parental information was gathered through standardized interviews and questionnaires. Findings were compared with those from the literature.

RESULTS

All participants showed profound intellectual disability, amiable demeanour with minimal maladaptive behaviours, severe impairments of communication and language, and intense, frequent motor stereotypies. Impairments in all participants were beyond what would be expected for cognitive abilities, fitting a classification of ASD.

INTERPRETATION

Patients with PTHS are characterized not only by specific physical and genetic manifestations but also by specific behavioural and cognitive characteristics. Studying behaviour and cognition may improve diagnosis and prognosis, allows recognition of comorbidities, and contributes to adequate counselling of families.

Posttraumatic stress disorder: shifting toward a developmental framework

This article reviews the current classification of posttraumatic stress disorder and its limitations when applied to youth. Distinctions are made between single-event and multiple-event traumas. Diagnosis, neurobiology, treatment development, and treatment outcomes are presented. A summary of current empirical interventions is provided. The authors present implications for future research and for clinical practice.

Patterns of developmental trajectories in toddlers with autism spectrum disorder

OBJECTIVE

Our objective was to follow toddlers referred for risk of autism, using standardized observational measures administered frequently from age 18 months to age 36 months.

METHOD

Sixty-five children who were consecutive referrals and 13 children from other research projects were seen approximately every 2 months, from age 18 months to age 36 months, for standardized assessments and clinical judgments by the same examiner and every 6 months by an examiner blind to previous scores.

RESULTS

Thirty children never received an autism spectrum disorder (ASD) diagnosis; 48 children (all referrals) received at least 1 diagnosis of ASD. The best trajectory typology, using Autism Diagnostic Observation Schedule (ADOS) scores, revealed 4 trajectory classes with high probabilities for fit to the most likely class: severe persistent (21%), worsening (21%), improving (19%), and nonspectrum (40%). Classes differed by trajectories in verbal and nonverbal mental ages; never-ever ASD groups differed on Autism Diagnostic Interview-Revised (ADI-R) domain scores and clinician judgments, but improving-worsening trajectory groups did not.

CONCLUSIONS

The results replicated the findings from studies of infants whose siblings have autism and infants whose siblings do not have autism, suggesting variability in early trajectories and supporting the need for early identification, regular monitoring, and standardized assessments of young children suspected of having ASD.

ACORNS: a tool for the visualisation and modelling of atypical development

Across many academic disciplines visualisation and notation systems are used for modelling data and developing theory, but in child development visual models are not widely used; yet researchers and students of developmental difficulties may benefit from a visualisation and notation system which can clearly map developmental outcomes and trajectories, and convey hypothesised dynamic causal pathways. Such a system may help understanding of existing accounts and be a tool for developing new theories. We first present criteria that need to be met in order to provide fully nuanced visualisations of development, and discuss strengths and weaknesses of the visualisation system proposed by Morton. Secondly, we present a tool we have designed to give more precise accounts of development while also being accessible, intuitive and visually appealing. We have called this an Accessible Cause-Outcome Representation and Notation System (ACORNS). This system provides a framework for clear mapping and modelling of developmental sequences, illustrating more precisely how functions change over time, how factors interact with the environment, and the absolute and relative nature of causal outcomes. We provide a new template, a set of rules for the appropriate use of boxes and arrows, and a set of visually accessible indicators that can be used to show more precisely relative rates, degrees and variance of functioning over different capacities at different time points. We have designed ACORNS to give a precise and clear visualisation of how development unfolds; allowing the representation of less 'static' and more transactional models of developmental difficulties. We hope ACORNS will help students, clinicians and theoreticians across disciplines to better represent nuances of debates, and be a seed for the development of new theory.

Development and validation of the Arizona Cognitive Test Battery for Down syndrome

Neurocognitive assessment in individuals with intellectual disabilities requires a well-validated test battery. To meet this need, the Arizona Cognitive Test Battery (ACTB) has been developed specifically to assess the cognitive phenotype in Down syndrome (DS). The ACTB includes neuropsychological assessments chosen to 1) assess a range of skills, 2) be non-verbal so as to not confound the neuropsychological assessment with language demands, 3) have distributional properties appropriate for research studies to identify genetic modifiers of variation, 4) show sensitivity to within and between sample differences, 5) have specific correlates with brain function, and 6) be applicable to a wide age range and across contexts. The ACTB includes tests of general cognitive ability and prefrontal, hippocampal and cerebellar function. These tasks were drawn from the Cambridge Neuropsychological Testing Automated Battery (CANTAB) and other established paradigms. Alongside the cognitive testing battery we administered benchmark and parent-report assessments of cognition and behavior. Individuals with DS (n=74, ages 7-38 years) and mental age (MA) matched controls (n=50, ages 3-8 years) were tested across 3 sites. A subsample of these groups were used for between-group comparisons, including 55 individuals with DS and 36 mental age matched controls. The ACTB allows for low floor performance levels and participant loss. Floor effects were greater in younger children. Individuals with DS were impaired on a number ACTB tests in comparison to a MA-matched sample, with some areas of spared ability, particularly on tests requiring extensive motor coordination. Battery measures correlated with parent report of behavior and development. The ACTB provided consistent results across contexts, including home vs. lab visits, cross-site, and among individuals with a wide range of socio-economic backgrounds and differences in ethnicity. The ACTB will be useful in a range of outcome studies, including clinical trials and the identification of important genetic components of cognitive disability.

Social cognition in children with Down's syndrome: challenges to research and theory building

Characterising how socio-cognitive abilities develop has been crucial to understanding the wider development of typically developing children. It is equally central to understanding developmental pathways in children with intellectual disabilities such as Down's syndrome. While the process of acquisition of socio-cognitive abilities in typical development and in autism has received considerable attention, socio-cognitive development in Down's syndrome has received far less scrutiny. Initial work in the 1970s and 1980s provided important insights into the emergence of socio-cognitive abilities in the children's early years, and recently there has been a marked revival of interest in this area, with research focusing both on a broader range of abilities and on a wider age range. This annotation reviews some of these more recent findings, identifies outstanding gaps in current understanding, and stresses the importance of the development of theory in advancing research and knowledge in this field. Barriers to theory building are discussed and the potential utility of adopting a transactional approach to theory building illustrated with reference to a model of early socio-cognitive development in Down's syndrome. The need for a more extensive model of social cognition is emphasised, as is the need for larger-scale, finer-grained, longitudinal work which recognises the within-individual and within-group variability which characterises this population. The value of drawing on new technologies and of adapting innovative research paradigms from other areas of typical and atypical child psychology is also highlighted.