An analysis of the criteria used to diagnose children with Nonverbal Learning Disability (NLD)

Visual-Motor Integration Deficits in 3q29 Deletion Syndrome

3q29 deletion syndrome (3q29del) is associated with neuropsychiatric and neurodevelopmental phenotypes. We previously reported that graphomotor weakness is present in up to 78% of individuals with 3q29del. We have now explored nuances of the graphomotor phenotype and its association with other comorbidities in this population. Participants were recruited from the online 3q29 registry (3q29deletion.org) for two days of deep phenotyping. 32 individuals with 3q29del (62.5% male) were evaluated with the Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) to assess visual-motor integration. Participants were also evaluated with measures of cognitive ability, executive function, adaptive behavior, and school function. Males with 3q29del performed significantly worse than females on the VMI and Motor Coordination subtest. VMI performance was significantly associated with ADHD diagnosis and cognitive ability. Compared to published data from individuals with 22q11.2 deletion syndrome, individuals with 3q29del showed significantly more impairment. The 3q29 deletion is associated with substantial deficits in visual-motor integration, Visual Perception, and Motor Coordination. Our data suggests that 3q29del may qualify as a nonverbal learning disability. Future studies should assess whether individuals with 3q29del would benefit from early interventions, including occupational therapy.

Looking Ahead: Advancing Measurement and Analysis of the Block Design Test Using Technology and Artificial Intelligence

The block design test (BDT) has been used for over a century in research and clinical contexts as a measure of spatial cognition, both as a singular ability and as part of more comprehensive intelligence assessment. Traditionally, the BDT has been scored using methods that do not reflect the full potential of individual differences that could be measured by the test. Recent advancements in technology, including eye-tracking, embedded sensor systems, and artificial intelligence, have provided new opportunities to measure and analyze data from the BDT. In this methodological review, we outline the information that BDT can assess, review several recent advancements in measurement and analytic methods, discuss potential future uses of these methods, and advocate for further research using these methods.

"Picture this from there": spatial perspective-taking in developmental visuospatial disorder and developmental coordination disorder

Introduction

Either Developmental Visuospatial Disorder (DVSD) and Developmental Coordination Disorder (DCD) present with difficulties in visuospatial processing, even though entailing different degrees of impairment. Among the visuospatial domain, spatial perspective taking is essential to interact with the environment and is significantly involved in many daily activities (e.g., environment navigation and spatial orienting). Notwithstanding, no previous studies have investigated this spatial domain in children with DVSD and limited evidence is available regarding DCD. Consistent with a transdiagnostic approach, the first goal of the present study was to compare spatial perspective taking abilities of these groups, also including a control group of not diagnosed peers (ND). Secondly, the role of different fine-motor and visuo-spatial predictors on the spatial perspective taking performance was considered.

Method

A total of 85 participants (DVSD = 26; DCD = 26; ND = 33), aged between 8 and 16 years old, were included in the study. Tasks assessing spatial perspective taking, fine-motor, visual imagery, and mental rotation skills, as well as visuo-spatial working memory were administered.

Results and Discussion

Overall, our results confirmed weaknesses in spatial perspective taking in both clinical groups, with the DVSD obtaining the lowest scores. Similarities and differences in the predictors accounting for the performance in the spatial perspective taking task emerged, suggesting the possible employment of different fine-motor or visuospatial strategies by group. Findings are discussed considering the potential impact they may have both in research and clinical practice.

Estimating the prevalence of Non-Verbal Learning Disability (NVLD) from the ABCD sample

Non-Verbal Learning Disability (NVLD) is a neurodevelopmental disorder characterized by deficits in processing visuospatial information but with age-appropriate verbal skills. This cognitive profile has been hypothesized to be associated with atypical white matter, but at the present there is a lack of evidence for this hypothesis. Currently, the condition is not characterized within the main diagnostic systems, in part because no clear set of criteria for characterizing the disorder exists. This report is the first attempt to estimate NVLD prevalence, using two sets of diagnostic criteria, in a large sample of over 11,000 children who were selected without regards to problems of specific nature, either psychological, neurological, physical and/or social. Furthermore, it examined the association between the profile of cognitive abilities and aspects of whole-brain white matter measures in children with and without symptoms associated with NVLD. Participants were drawn from the Adolescent Brain Cognitive Development (ABCD) study, a 10-year longitudinal study of 11,876 children in the U.S. The data used in the present study were drawn from the initial testing point at which the children were 9-10 years old. Prevalence of NVLD based on two distinct sets of criteria, correlations between the measures used to create the criteria, correlations between criteria measures and measures of white matter integrity. The cognitive criteria included measures of visuospatial processing, reading, intelligence and social skills. By varying the cut-offs applied to social skills in conjunction with visuo-spatial difficulties, spared reading skills and intelligence scores, we calculated prevalence for two NVLD groups. White matter characteristics were measures of volume, fractional anisotropy and mean diffusivity. Based on the criteria used, the estimated prevalence of NVLD varied from 1 to 8%. Furthermore, children with NVLD showed a dissociation between measures of visuo-spatial processing not observed in non-NVLD children. At the neurological level, findings provide preliminary evidence of associations between the cognitive profile of NVLD and abnormalities in white matters tracts. The present study documents that exists, within this large non-selected sample, a proportion of youth who show evidence of NVLD. Given those results, it appears essential to establish the best diagnostic criteria, to improve the treatment options and quality of life for children with this disorder.

Neurocognitive and psychosocial profiles of children with Turner syndrome

PURPOSE

Patients with Turner syndrome (TS) have distinct neurocognitive and psychosocial characteristics. However, few clinical studies have reported neuropsychological findings in Korean patients. This study investigated the neurocognitive and psychosocial profiles of Korean children with TS.

METHODS

This retrospective cross-sectional study analyzed 20 pediatric patients (<18 years) with TS at the Department of Pediatric Endocrinology at Yonsei University Severance Children's Hospital in South Korea from January 2016 to March 2019. We selected 20 age- and sex-matched controls from among those who visited the endocrinology clinic and were confirmed to have no clinical abnormalities. All participants underwent several neuropsychological tests.

RESULTS

In the Korean Wechsler Intelligence Scale for Children-IV test, the Full-Scale Intelligence Quotient of the TS group was within the normal range. The Perceptual Reasoning Index, Working Memory Index, and Processing Speed Index scores were significantly lower in the TS group than in the control group. In contrast, the Verbal Comprehension Index did not differ significantly between the groups. The Comprehensive Attention Test results showed that the TS group displayed borderline visual selective attention. The social quotient score was significantly lower in the TS group than in the control group.

CONCLUSION

Pediatric patients with TS in Korea displayed distinct neurocognitive and psychosocial characteristics. Patients in the TS group maintained their verbal function, but their attention, visuospatial function, and social competence were low. Our findings will contribute to the development of education programs for patients with TS to improve their neurocognitive and psychosocial functioning.

Trajectory assessments of cognitive, visuospatial, and academic profile in nonverbal learning disability (visuospatial developmental disorder)

Substantial progress has been made in defining children with nonverbal learning disability (NLD), but longitudinal studies are still lacking. To start filling this gap, we examined changes in general cognitive functioning, visuo-constructive skills, and academic profiles in a group of children with NLD, also taking into account any internalizing and externalizing symptom as transdiagnostic features. A total of 30 participants (24 boys) diagnosed with NLD were tested twice, with a three-year gap between the two assessments (T1: at age 8-13; T2: at 11-16), on their cognitive profile, visuospatial abilities, and academic performance (i.e., reading, writing and arithmetic abilities). At T2, any internalizing and externalizing symptom was also investigated. Statistically significant differences emerged between the two assessments in terms of the WISC-IV Perceptual Reasoning Index (PRI), handwriting speed and arithmetical fact retrieval. The NLD profile seems to be characterized by a relative stability in its core features during a child's development, as regards both weaknesses (i.e., visuospatial processing) and strengths (i.e., verbal abilities). The presence of internalizing and externalizing symptoms also suggested the importance to analyze transdiagnostic features rather than only sharp boundaries between conditions.

Resting State Dynamic Reconfiguration of Spatial Attention Cortical Networks and Visuospatial Functioning in Non-Verbal Learning Disability (NVLD): A HD-EEG Investigation

Nonverbal learning disability (NVLD) is a neurodevelopmental disorder characterized by deficits in visuospatial processing but spared verbal competencies. Neurocognitive markers may provide confirmatory evidence for characterizing NVLD as a separate neurodevelopmental disorder. Visuospatial performance and high-density electroencephalography (EEG) were measured in 16 NLVD and in 16 typically developing (TD) children. Cortical source modeling was applied to assess resting-state functional connectivity (rs-FC) in spatial attention networks (dorsal (DAN) and ventral attention networks (VAN)) implicated in visuospatial abilities. A machine-learning approach was applied to investigate whether group membership could be predicted from rs-FC maps and if these connectivity patterns were predictive of visuospatial performance. Graph theoretical measures were applied to nodes inside each network. EEG rs-FC maps in the gamma and beta band differentiated children with and without NVLD, with increased but more diffuse and less efficient functional connections bilaterally in the NVLD group. While rs-FC of the left DAN in the gamma range predicted visuospatial scores for TD children, in the NVLD group rs-FC of the right DAN in the delta range predicted impaired visuospatial performance, confirming that NVLD is a disorder with a predominant dysfunction in right hemisphere connectivity patterns.

Severe developmental topographical disorientation associated with ADHD and dyscalculia: A case report

We report the clinical case of AB, a right-handed 19-year-old woman who presents severe developmental topographical disorientation, a relatively rare syndrome, leading to difficulties in navigating in familiar (and novel) environments. This symptomatology appears without acquired cerebral damage (MRI described as normal) nor more global cognitive disability (high degree of education achieved). An extensive assessment of spatial cognition with different aspects of underlying cognitive processes is first presented. Second, the patient's preserved cognitive abilities and her major difficulties in calculation, as well as her attention deficit, as seen in a detailed neuropsychological assessment, are reported. For the first time to our knowledge, we show that developmental topographical disorientation can be associated with other developmental cognitive disorders affecting number processing (dyscalculia) and attention (Attention Deficit-Hyperactivity Disorder (ADHD)). We discuss the links between these different cognitive processes in relation to visuo-spatial working memory and magnitude representation, which could represent common denominators for all these syndromes. This case report highlights the importance of thoroughly assessing potentially associated neurocognitive disorders in developmental topographical disorientation. In addition, it highlights the necessity to keep in mind the prevalence of spatial difficulties in the assessment of children and adolescents with other neurodevelopmental syndromes. Finally, this case study raises a new question about the nosology of developmental disorders affecting the visuo-spatial and spatial domains.

Do comorbid symptoms discriminate between autism spectrum disorder, ADHD and nonverbal learning disability?

Characterizing the functioning of individuals with neurodevelopmental disorders is crucial to their diagnosis. Research has found that children with different neurodevelopmental disorders, including autism spectrum disorders (ASD), attention deficit and hyperactivity disorder (ADHD), and nonverbal learning disability (NLD), may have comorbid symptoms of anxiety and depression, and problems with pragmatic language. The main aim of the present study was to identify any differences in the above-mentioned comorbid symptoms associated with these clinical profiles. A second aim was to establish how well signs of pragmatic language difficulties could discriminate between the three clinical profiles, in terms of their diagnostic power. For this purpose, 107 participants from 8 to 16 years old with a diagnosis of ASD, ADHD or NLD were compared with a group of typically-developing children. Self-reports on symptoms of anxiety and depression, and parents' reports on social and communication problems were analyzed. Our findings confirmed that symptoms of anxiety and depression, and problems with pragmatic language are associated with different neurodevelopmental disorders, but not in the same way. In terms of diagnostic power, we found that pragmatic language difficulties clearly discriminated children with ASD, ADHD or NLD from typically-developing children. Importantly, pragmatic language difficulties also discriminated adequately between ASD and NLD. Our findings are discussed in terms of the value of considering comorbid symptoms to obtain a more accurate diagnosis of neurodevelopmental disorders.

Editorial: Time to Recognize Nonverbal Learning Disability to Foster Advances in Its Research

The definitions of most of the currently recognized neurodevelopmental disorders and the criteria used to identify them have seen important changes since their inclusion in diagnostic classification systems (see, for instance, how the definitions of specific learning disorders and autism spectrum disorder (ASD) have been revised in successive versions of DSM). As is the case with many other mental conditions, our understanding of neurodevelopmental disorders is continuously being updated in the light of new research findings. However, this has not been the case for nonverbal learning disability. More than 50 years since it was first described,¹ there is still no consensus on the merits of identifying it as a separate disorder or using a clear and acknowledged diagnostic label. Instead of trying to establish why nonverbal learning disability has yet to be included in the diagnostic manuals, this editorial examines why recognized criteria for the condition would improve research in this field and avoid the negative consequences of continuing to conduct research without adopting shared criteria.

Systematic Review: Nonverbal Learning Disability

OBJECTIVE

To summarize the current state of the research literature on nonverbal learning disability (NVLD), including criteria used to define NVLD in research contexts and the quality of the extant research; and to determine what research can tell us about ways in which NVLD is distinct from DSM neurodevelopmental disorders and typical development.

METHOD

A systematic search of 7 databases was conducted to identify research on NVLD published through February 2019. Criteria used to define NVLD were extracted from identified studies and sorted by category. Each study was assessed for risk of bias and rated "good," "fair," or "poor;" findings from studies rated good or fair were summarized.

RESULTS

A total of 61 articles (63 studies) met inclusion criteria. There was great heterogeneity in the criteria used to define NVLD. Deficits in visuospatial ability/intelligence was the most common criterion used, followed by discrepancy between verbal and nonverbal intelligence (VIQ>PIQ split of 10 or greater). All studies were cross-sectional and most included small, poorly described samples. Most studies focused on children and young adolescents. Eight studies were rated as good, 42 as fair, and 13 as poor. Review of results from the 50 good or fair studies suggest that there is sufficient evidence that youths with NVLD (as defined by significant deficits in visuospatial abilities) can be clearly differentiated from their typically developing peers, those with verbal learning disorders, and from other clinical groups (eg, individuals with high functioning autism).

CONCLUSION

A standard set of criteria for determining an NVLD diagnosis would greatly improve research studies and the possibility of inclusion in the DSM and the International Classification of Diseases.

Motor and Visual-spatial Cognitive Abilities in Children Treated for Infantile Esotropia

While many studies have investigated links between motor and visual spatial cognitive abilities in typically developing children, only a few studies have tested this link among children with innate handicaps. Therefore, we assessed motor abilities (using the M-ABC-2) and visual spatial cognitive skills (using the Block Design subtest of the WPPSI-III and a picture mental rotation task, PRT) of 5-7 year old typically developing children (n= 17) and same-aged children with severe deficits in stereopsis due to infantile esotropia (n= 17). Compared to the typically developing children, children with esotropia showed significantly poorer motor performances, especially in manual dexterity and ball skills, and significantly poorer and slower performance on the visual spatial cognitive tasks. Especially the girls treated for infantile esotropia needed more time to mentally rotate the pictures of the PRT correctly. Overall, this study showed that perceptual, motor and cognitive processes are interconnected and that children treated for infantile esotropia had an increased risk of motor and visual spatial cognitive deficits.

Altered structure and functional connectivity of the hippocampus are associated with social and mathematical difficulties in nonverbal learning disability

The hippocampus is known to play a critical role in a variety of complex abilities, including visual-spatial reasoning, social functioning, and math. Nonverbal learning disability (NVLD) is a neurodevelopmental disorder characterized by deficits in visual-spatial reasoning that are accompanied by impairment in social function or mathematics, as well as motor or executive function skills. Despite the overlap between behaviors supported by the hippocampus and impairments in NVLD, the structure and function of the hippocampus in NVLD has not been studied. To address this gap in the literature, we first compared hippocampal volume and resting-state functional connectivity in children with NVLD (n = 24) and typically developing (TD) children (n = 20). We then explored associations between hippocampal structure, connectivity, and performance on measures of spatial, social, and mathematical ability. Relative to TD children, those with NVLD showed significant reductions in left hippocampal volume and greater hippocampal-cerebellar connectivity. In children with NVLD, reduced hippocampal volume associated with worse mathematical problem solving. Although children with NVLD exhibited more social problems (social responsiveness scale [SRS]) and higher hippocampal-cerebellar connectivity relative to TD children, greater connectivity was associated with fewer social problems among children with NVLD but not TD children. Such an effect may suggest a compensatory mechanism. These structural and functional alterations of the hippocampus may disrupt its putative role in organizing conceptual frameworks through cognitive mapping, thus contributing to the cross-domain difficulties that characterize NVLD.

"Building blocks and drawing figures is not the same": Neuropsychological bases of block design and Rey figure drawing in typically developing children

Several studies investigated the neuropsychological bases of spatial construction in developmental samples. However, no study directly tested whether the pattern of the neuropsychological processes implied in spatial construction changed depending on whether a block building or a figure drawing task is considered. Here, we used the path analysis to test the direct and indirect effects of verbal abilities (naming and verbal knowledge), executive functions, figure disembedding and mental rotation on two classical spatial construction tasks: the Rey-Osterrieth Complex Figure (ROCF) and the Block Design (BD). We recruited a sample of 186 typically developing children (age range: 7-12 years). Results showed that ROCF copying was directly influenced by age and figure disembedding, and it was indirectly affected by executive functions, naming and verbal knowledge, whereas BD was influenced in a direct way by verbal knowledge, figure disembedding and mental rotation and indirectly affected by executive functions and naming skills. Moreover, the results showed a full measurement invariance of the path model between sexes, whereas only partial invariance was found for age. Thus, we tested the model in two age groups (age ranges: 7-9.5 and 9.6-12 years) and found that the relationships between the variables of the model changed across development. Although other variables might be relevant to spatial construction, the present findings demonstrate different neuropsychological bases of drawing figures and building blocks in typically developing children.

A comparison of local-global visuospatial processing in autism spectrum disorder, nonverbal learning disability, ADHD and typical development

BACKGROUND

Research on visuospatial functioning has revealed cognitive challenges for children with autism spectrum disorder (ASD), nonverbal learning disability (NLD) and attention deficit hyperactivity disorder (ADHD). These disorders are characterized by some overlapping symptoms, making their diagnosis a challenge.

AIMS

The study aims to clarify the role of visuospatial abilities in their neuropsychological profiles by investigating different visuospatial domains and their interplay with the local-global processing.

METHOD AND PROCEDURES

Participants (N = 150) with ASD, NLD, or ADHD were compared with typically-developing (TD) children on visuospatial processing speed, visuo-perceptual abilities, visuo-constructive abilities, and visuospatial working memory. Generalized mixed-effects models were performed and receiver operating characteristic curves were estimated to express the usefulness of a local-global processing index in discriminating groups.

OUTCOMES AND RESULTS

The NLD group was impaired in all domains; children with ADHD revealed a heterogeneous profile, with greater impairments in visuospatial processing speed; ASD and TD groups were comparable. The local-global processing index had predictive power in discriminating among groups in visuo-constructive task.

CONCLUSIONS AND IMPLICATIONS

The study of visuospatial abilities of children with ASD, NLD and ADHD might help to understand strengths and weaknesses in their neuropsychological profile and to differentiate between them. Clinical implications of these findings are discussed.

Estimated Prevalence of Nonverbal Learning Disability Among North American Children and Adolescents

IMPORTANCE

Nonverbal learning disability (NVLD) is a neurodevelopmental disorder characterized by deficits in visual-spatial processing but not in reading or verbal ability; in addition, problems in math calculation, visual executive functioning, fine-motor skills, and social skills are often present. To our knowledge, there are no population-based estimates of the prevalence of NVLD in community samples.

OBJECTIVE

To estimate the prevalence of the NVLD cognitive profile in 3 independent samples of children and adolescents from studies centered around brain imaging in the US and Canada.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from 2 samples recruited from the community and overselected for children with psychiatric disorders (Healthy Brain Network [HBN], January 1, 2015, to December 31, 2019, and Nathan Kline Institute-Rockland Sample [NKI], January 1, 2011, to December 31, 2018) and 1 community-ascertained population sample (Saguenay Youth Study [SYS], January 1, 2003, to December 31, 2012) overselected for active maternal smoking during pregnancy.

MAIN OUTCOMES AND MEASURES

Prevalence of NVLD. Criteria for NVLD were based on clinical records of deficits in visual-spatial reasoning and impairment in 2 of 4 domains of function (fine-motor skills, math calculation, visual executive functioning, and social skills). Sample weighting procedures adjusted for demographic differences in sample frequencies compared with underlying target populations. Inflation factor weights accounted for overrepresentation of psychiatric disorders (HBN and NKI samples).

RESULTS

Across 3 independent samples, the prevalence of NVLD was estimated among 2596 children and adolescents aged 6 to 19 years (mean [SD] age, 12.5 [3.4] years; 1449 male [55.8%]). After sample and inflation weights were applied, the prevalence of NVLD was 2.78% (95% CI, 2.03%-3.52%) in the HBN sample and 3.9% (95% CI, 1.96%-5.78%) in the NKI sample. In the SYS sample, the prevalence of NVLD was 3.10% (95% CI, 1.93%-4.27%) after applying the sample weight. Across samples and estimation strategies, the population prevalence of NVLD was estimated to range from 3% to 4%. When applied to the US population younger than 18 years, 2.2 million to 2.9 million children and adolescents were estimated to have NVLD.

CONCLUSIONS AND RELEVANCE

The findings suggest that the prevalence of NVLD in children and adolescents may be 3% to 4%. Given that few youths are diagnosed with NVLD and receive treatment, increased awareness, identification of the underlying neurobiological mechanisms, and development and testing interventions for the disorder are needed.

Spatial Network Connectivity and Spatial Reasoning Ability in Children with Nonverbal Learning Disability

Nonverbal Learning Disability (NVLD) is characterized by deficits in visual-spatial, but not verbal, reasoning. Nevertheless, the functioning of the neural circuits supporting spatial processing have yet to be assessed in children with NVLD. We compared the resting state functional connectivity of a spatial brain network among children with NVLD, children with reading disorder (RD), and typically developing (TD) children. Seventy-five participants (7-15 years old) were included in the study (20 TD, 24 NVLD, and 31 RD). Group differences in global efficiency and functional connectivity among 12 regions comprising a previously defined spatial network were evaluated. Associations with behavior were explored. Global efficiency of the spatial network associated positively with spatial ability and inversely with socioemotional problems. Within the spatial network, associations between left posterior cingulate (PCC) and right retrosplenial cortical activity were reduced in children with NVLD relative to those without spatial deficits (RD and TD). Connectivity between left PCC and right posterior cerebellum (Crus I and II) was reduced in both groups of children with learning disabilities (NVLD and RD) relative to TD children. Functional connectivity of the spatial network was atypically associated with cognitive and socioemotional performance in children with NVLD. Identifying a neurobiological substrate for NVLD provides evidence that it is a discrete clinical entity and suggests targets for treatment.

Nonverbal learning disability (developmental visuospatial disorder)

Nonverbal learning disability is a neurodevelopmental disorder with a core deficit in visuospatial processing with possibly associated problems in attention, motor, academic, and social skills, but without associated neurologic or genetic syndromes. The present chapter, after a brief historic overview of this disorder, will present fresh evidence that clearly shows neuropsychologic and neuroanatomical distinctions between children with nonverbal learning disability and those with other neurodevelopmental disorders. It ends with an attempt to find shared and valid diagnostic criteria. Acknowledging this disorder as a distinct diagnostic category will open up new research avenues with important scientific and clinical implications.

The Effect of Perceptual-Motor Training on Executive Functions in Children with Non-Verbal Learning Disorder

PURPOSE

Research shows an atypical cognitive process in children with nonverbal learning disorder (NLD) compared to typically developing children, but a wealth of information indicates that physical activity can influence cognitive processes. However, little is known about the effects of perceptual-motor training and its impact on the cognitive process of children with NLD. Thus, the major goals of this study are to compare the executive functions (EFs) in children with NLD with typically developing children and then to investigate the effect of perceptual-motor training on EFs of children with NLD.

METHODS

To achieve the first goal, 400 typically developing (IQ >80) and NLD children (7-13 years old) were randomly selected in the city of Mashhad, Iran, during the period 2017-2018. As for the second goal, 50 children with NLD were randomly assigned to an experimental or control group. To evaluate executive functions, Delis-Kaplan executive function system test was used at the pretest, posttest, and 3-month follow-up. The experimental group received the Werner and Reini's perceptual-motor training program in sixteen 45-min sessions (three sessions per week), but the control group did not receive any intervention.

RESULTS

The results showed that children with NLD were significantly weaker than typically developing children in London Tower Test (t (38) = -4.662, p <0.01), Trail Making Test (t (33.926) = -3.11, p <0.01), Card Sorting Test (t (38) = -3.427, p <0.01), and Stroop Color Test (t (30.035) = -5.876, p <0.01). The Pilates training had an obvious effect on enhancing the performance of participants in the experimental group (p<0.001), but similar results were not observed in the control group.

CONCLUSION

Children with NLD have problems in EFs, but perceptual-motor training can be used as an effective intervention for these children.

Growth in Math Computation among Monolingual and English Language Learners:Does the Executive System have a Role?

This cohort-sequential study explored the components of working memory that underlie math calculation in elementary school children who are monolingual (English) or English language learners (ELLs) whose first language is Spanish. To this end, children (N = 789) in grades 1, 2, and 3 at wave 1 were administered a battery of math, vocabulary, reading and cognitive (short-term memory [STM], working memory [WM], rapid naming, and inhibition) measures. The battery of tests was administered again one year and two years later to the same participants. Three important findings emerged. First, along with naming speed, the results suggest that growth in the executive component of WM was significantly related to growth in calculation performance. Second, performance on measures of reading, fluid intelligence, naming speed and executive processes in wave 1 were significantly related to wave 3 math calculation performance. Finally, the full latent growth model showed that monolingual and ELL children were statistically comparable in computation at wave 3. Thus, strong support was found for the notion that the executive component of WM was related to math computation but weak support for the notion ELL children experienced a math achievement gap.

Identifying neuropsychological predictors of drawing skills in elementary school children

Much evidence indicates that drawing is related to different neuropsychological abilities in children. However, a comprehensive cognitive model of drawing in children is still lacking. Here, we conducted a study on the neuropsychological predictors of drawing in a sample of 142 typically developing elementary school children (M age = 8.8 years; SD = 1.1). Based on a path analysis, we examined the contribution of visual perception (matching geometrical figures), complex spatial abilities (e.g., complex figures identification and mental rotation), visual attention, working memory, verbal and visual-motor skills, as well as of gender, age and socio-economic status, to copying the Rey-Osterrieth Complex Figure (ROCF). Results showed that ROCF copying was influenced in a specific and additive way by visual perception, visual-motor coordination, and verbal abilities as well as age, while it was indirectly related to visual attention, working memory, and to complex spatial abilities. These findings provide the grounds for identifying the neuropsychological bases of drawing in elementary school children.

The discrepancy between verbal and visuoperceptual IQ in children with a specific learning disorder: An analysis of 1624 cases

Children with a specific learning disorder (SLD) are often characterized by marked intellectual strengths and weaknesses. In the last few years, research has focused on a common discrepancy between low working memory and processing speed on the one hand, and high verbal and visuoperceptual intelligence on the other. SLD profiles featuring a specific discrepancy between verbal and visuoperceptual abilities have been only marginally considered, however, and their systematic comparison vis-à-vis typically-developing (TD) populations has yet to be conducted. The present study examined a dataset of 1624 WISC-IV profiles of children with a diagnosis of SLD. It emerged that the proportion of children with a Verbal Comprehension Index (VCI) at least 1.5 SD (22 standardized points) lower than their scores on the Perceptual Reasoning Index (PRI) was larger than the proportion of SLD children with the opposite discrepant profile; it was also larger than the same proportion found among TD children. Comparing the two discrepant profiles revealed that the children also differed by type of learning difficulty, gender, and performance in the WISC-IV Symbol search task. Further examination suggested that children who were discrepant and also distinctly poor in visuoperceptual intelligence were particularly slow in general processing.

A research framework to isolate visuospatial from childhood motor coordination phenotypes

Clinicians acknowledge the presence of developmental cognitive phenotypes mainly characterized by a specific visuospatial impairment in presence of intact verbal functioning (usually referred as Nonverbal Learning Disability: NLD) since many decades, without providing sufficient empirical evidence supporting their nosological validity and inclusion in current diagnostic manuals. This contribution suggests that the goal of including NLD in future diagnostic manuals could be achieved only be the demonstration of the validity of this hypothesized clinical category. Considering the blind spot of empirical literature represented by the differential diagnosis of NLD, this issue should the primary focus of empirical research supported by a renewed interest on NLD. Both neurophysiological and clinical evidence suggest that the differential diagnosis and the related empirical comparison should be primarily settled with Developmental Coordination Disorder, looking for the possible identification of children presenting a visuospatial impairment in absence of severe motor coordination impairment. In conclusion, further studies are needed to support the validity of NLD as valid diagnostic category to be included in future revisions of diagnostic manuals.

Reading and Writing Skills in Children With Specific Learning Disabilities With and Without Developmental Coordination Disorder

This pilot study is to investigate the influence of a developmental coordination disorder (DCD) comorbidity in a group of children with learning disability (LD). Reading and writing were assessed to investigate if the coexistence of a motor impairment can worsen writing quality, speed, and reading accuracy. A sample of 33 LD children (aged 7-11 years) was divided in two subgroups, on the base of their scores on the Movement Assessment Battery for Children: LD-only (n = 14) and LD with a comorbidity for DCD (LD-DCD, n = 19). No differences were found in handwriting speed, but significant differences were found in handwriting quality: LD-DCD children showed a worst performance. Reading words and nonwords accuracy was more impaired in LD-only children than in LD-DCD children. Group differences suggest a poorer phonological decoding of the LD-only sample, whereas worst cursive handwriting legibility scores are typical of the motor-impaired subgroup.

Local and global processing in block design tasks in children with dyslexia or nonverbal learning disability

Visuo-constructive and perceptual abilities have been poorly investigated in children with learning disabilities. The present study focused on local or global visuospatial processing in children with nonverbal learning disability (NLD) and dyslexia compared with typically-developing (TD) controls. Participants were presented with a modified block design task (BDT), in both a typical visuo-constructive version that involves reconstructing figures from blocks, and a perceptual version in which respondents must rapidly match unfragmented figures with a corresponding fragmented target figure. The figures used in the tasks were devised by manipulating two variables: the perceptual cohesiveness and the task uncertainty, stimulating global or local processes. Our results confirmed that children with NLD had more problems with the visuo-constructive version of the task, whereas those with dyslexia showed only a slight difficulty with the visuo-constructive version, but were in greater difficulty with the perceptual version, especially in terms of response times. These findings are interpreted in relation to the slower visual processing speed of children with dyslexia, and to the visuo-constructive problems and difficulty in using flexibly-experienced global vs local processes of children with NLD. The clinical and educational implications of these findings are discussed.

Pragmatics of language and theory of mind in children with dyslexia with associated language difficulties or nonverbal learning disabilities

The present study aims to find empirical evidence of deficits in linguistic pragmatic skills and theory of mind (ToM) in children with dyslexia with associated language difficulties or nonverbal learning disabilities (NLD), when compared with a group of typically developing (TD) children matched for age and gender. Our results indicate that children with dyslexia perform less well than TD children in most of the tasks measuring pragmatics of language, and in one of the tasks measuring ToM. In contrast, children with NLD generally performed better than the dyslexia group, and performed significantly worse than the TD children only in a metaphors task based on visual stimuli. A discriminant function analysis confirmed the crucial role of the metaphors subtest and the verbal ToM task in distinguishing between the groups. We concluded that, contrary to a generally-held assumption, children with dyslexia and associated language difficulties may be weaker than children with NLD in linguistic pragmatics and ToM, especially when language is crucially involved. The educational and clinical implications of these findings are discussed.

Pitch perception deficits in nonverbal learning disability

The nonverbal learning disability (NLD) is a neurological dysfunction that affects cognitive functions predominantly related to the right hemisphere such as spatial and abstract reasoning. Previous evidence in healthy adults suggests that acoustic pitch (i.e., the relative difference in frequency between sounds) is, under certain conditions, encoded in specific areas of the right hemisphere that also encode the spatial elevation of external objects (e.g., high vs. low position). Taking this evidence into account, we explored the perception of pitch in preadolescents and adolescents with NLD and in a group of healthy participants matched by age, gender, musical knowledge and handedness. Participants performed four speeded tests: a stimulus detection test and three perceptual categorization tests based on colour, spatial position and pitch. Results revealed that both groups were equally fast at detecting visual targets and categorizing visual stimuli according to their colour. In contrast, the NLD group showed slower responses than the control group when categorizing space (direction of a visual object) and pitch (direction of a change in sound frequency). This pattern of results suggests the presence of a subtle deficit at judging pitch in NLD along with the traditionally-described difficulties in spatial processing.

Cognitive Clusters in Specific Learning Disorder

The heterogeneity among children with learning disabilities still represents a barrier and a challenge in their conceptualization. Although a dimensional approach has been gaining support, the categorical approach is still the most adopted, as in the recent fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. The introduction of the single overarching diagnostic category of specific learning disorder (SLD) could underemphasize interindividual clinical differences regarding intracategory cognitive functioning and learning proficiency, according to current models of multiple cognitive deficits at the basis of neurodevelopmental disorders. The characterization of specific cognitive profiles associated with an already manifest SLD could help identify possible early cognitive markers of SLD risk and distinct trajectories of atypical cognitive development leading to SLD. In this perspective, we applied a cluster analysis to identify groups of children with a Diagnostic and Statistical Manual-based diagnosis of SLD with similar cognitive profiles and to describe the association between clusters and SLD subtypes. A sample of 205 children with a diagnosis of SLD were enrolled. Cluster analyses (agglomerative hierarchical and nonhierarchical iterative clustering technique) were used successively on 10 core subtests of the Wechsler Intelligence Scale for Children-Fourth Edition. The 4-cluster solution was adopted, and external validation found differences in terms of SLD subtype frequencies and learning proficiency among clusters. Clinical implications of these findings are discussed, tracing directions for further studies.

Prevalence of inter-hemispheric asymetry in children and adolescents with interdisciplinary diagnosis of non-verbal learning disorder

OBJECTIVE

To describe clinical and epidemiological features of children and adolescents with interdisciplinary diagnosis of non-verbal learning disorder and to investigate the prevalence of inter-hemispheric asymmetry in this population group.

METHODS

Cross-sectional study including children and adolescents referred for interdisciplinary assessment with learning difficulty complaints, who were given an interdisciplinary diagnosis of non-verbal learning disorder. The following variables were included in the analysis: sex-related prevalence, educational system, initial presumptive diagnoses and respective prevalence, overall non-verbal learning disorder prevalence, prevalence according to school year, age range at the time of assessment, major family complaints, presence of inter-hemispheric asymmetry, arithmetic deficits, visuoconstruction impairments and major signs and symptoms of non-verbal learning disorder.

RESULTS

Out of 810 medical records analyzed, 14 were from individuals who met the diagnostic criteria for non-verbal learning disorder, including the presence of inter-hemispheric asymmetry. Of these 14 patients, 8 were male.

CONCLUSION

The high prevalence of inter-hemispheric asymmetry suggests this parameter can be used to predict or support the diagnosis of non-verbal learning disorder.

OBJETIVO

Descrever as características clínicas e epidemiológicas de crianças e adolescentes com transtorno de aprendizagem não verbal, e investigar a prevalência de assimetria inter-hemisférica neste grupo populacional.

MÉTODOS

Estudo transversal que incluiu crianças e adolescentes encaminhados para uma avaliação interdisciplinar, com queixas de dificuldades de aprendizagem e que receberam diagnóstico interdisciplinar de transtorno de aprendizagem não verbal. As variáveis avaliadas foram prevalência por sexo, sistema de ensino, hipóteses diagnósticas iniciais e respectivas prevalências, prevalência de condições em relação à amostra total, prevalência geral do transtorno de aprendizagem não verbal, prevalência de acordo com ano escolar, faixa etária no momento da avaliação, principais queixas familiares, presença assimetria inter-hemisférica, dificuldade em aritmética, alterações em visuoconstrução, e principais sinais e sintomas do transtorno de aprendizagem não verbal.

RESULTADOS

Dos 810 prontuários médicos analisados, 14 eram de indivíduos que preencheram os critérios diagnósticos para transtorno de aprendizagem não verbal, incluindo a assimetria inter-hemisférica. Destes 14 pacientes, 8 eram do sexo masculino.

CONCLUSÃO

A alta prevalência de assimetria inter-hemisférica sugere que este parâmetro possa ser usado como preditor ou reforçador para diagnóstico de transtorno de aprendizagem não verbal.

Spatial and numerical processing in children with non-verbal learning disabilities

Consistently with the idea that numbers and space interact with each other, the present paper aimed to investigate the impact of non-verbal learning disabilities (NVLD) on spatial and numerical processing. In order to do so, 15 NVLD and 15 control children were required to perform different spatial (the line bisection and Simon tasks) and numerical tasks (the number bisection, number-to-position and numerical comparison tasks). In every task, NVLD children presented lower accuracy scores than the control group. While both groups manifested similar pseudo-neglect and Simon effects, they however differed in the numerical comparison task: while control children presented the standard SNARC effect in the uncrossed and crossed postures, no SNARC effect was observed in the NVLD group. Our results therefore suggest that NVLD affects the accuracy and the nature of the mental number line by decreasing its precision and the saliency of its left-to-right orientation.

Deficits in visual short-term memory binding in children at risk of non-verbal learning disabilities

It has been hypothesized that learning disabled children meet short-term memory (STM) problems especially when they must bind different types of information, however the hypothesis has not been systematically tested. This study assessed visual STM for shapes and colors and the binding of shapes and colors, comparing a group of children (aged between 8 and 10 years) at risk of non-verbal learning disabilities (NLD) with a control group of children matched for general verbal abilities, age, gender, and socioeconomic level. Results revealed that groups did not differ in retention of either shapes or colors, but children at risk of NLD were poorer than controls in memory for shape-color bindings.

Psychosocial and Adaptive Deficits Associated With Learning Disability Subtypes

Children with specific learning disabilities (SLD) have deficits in the basic psychological processes that interfere with learning and academic achievement, and for some SLD subtypes, these deficits can also lead to emotional and/or behavior problems. This study examined psychosocial functioning in 123 students, aged 6 to 11, who underwent comprehensive evaluations for learning and/or behavior problems in two Pacific Northwest school districts. Using concordance-discordance model (C-DM) processing strengths and weaknesses SLD identification criteria, results revealed working memory SLD (n = 20), processing speed SLD (n = 30), executive SLD (n = 32), and no disability groups (n = 41). Of the SLD subtypes, repeated measures MANOVA results revealed the processing speed SLD subtype exhibited the greatest psychosocial and adaptive impairment according to teacher behavior ratings. Findings suggest processing speed deficits may be behind the cognitive and psychosocial disturbances found in what has been termed "nonverbal" SLD. Limitations, implications, and future research needs are addressed.

Memory and comprehension deficits in spatial descriptions of children with non-verbal and reading disabilities

The present study investigated the difficulties encountered by children with non-verbal learning disability (NLD) and reading disability (RD) when processing spatial information derived from descriptions, based on the assumption that both groups should find it more difficult than matched controls, but for different reasons, i.e., due to a memory encoding difficulty in cases of RD and to spatial information comprehension problems in cases of NLD. Spatial descriptions from both survey and route perspectives were presented to 9–12-year-old children divided into three groups: NLD (N = 12); RD (N = 12), and typically developing controls (TD; N = 15); then participants completed a sentence verification task and a memory for locations task. The sentence verification task was presented in two conditions: in one the children could refer to the text while answering the questions (i.e., text present condition), and in the other the text was withdrawn (i.e., text absent condition). Results showed that the RD group benefited from the text present condition, but was impaired to the same extent as the NLD group in the text absent condition, suggesting that the NLD children’s difficulty is due mainly to their poor comprehension of spatial descriptions, while the RD children’s difficulty is due more to a memory encoding problem. These results are discussed in terms of their implications in the neuropsychological profiles of children with NLD or RD, and the processes involved in spatial descriptions.

Augmented reality for the assessment of children's spatial memory in real settings

Short-term memory can be defined as the capacity for holding a small amount of information in mind in an active state for a short period of time. Although some instruments have been developed to study spatial short-term memory in real environments, there are no instruments that are specifically designed to assess visuospatial short-term memory in an attractive way to children. In this paper, we present the ARSM (Augmented Reality Spatial Memory) task, the first Augmented Reality task that involves a user's movement to assess spatial short-term memory in healthy children. The experimental procedure of the ARSM task was designed to assess the children's skill to retain visuospatial information. They were individually asked to remember the real place where augmented reality objects were located. The children (N = 76) were divided into two groups: preschool (5–6 year olds) and primary school (7–8 year olds). We found a significant improvement in ARSM task performance in the older group. The correlations between scores for the ARSM task and traditional procedures were significant. These traditional procedures were the Dot Matrix subtest for the assessment of visuospatial short-term memory of the computerized AWMA-2 battery and a parent's questionnaire about a child's everyday spatial memory. Hence, we suggest that the ARSM task has high verisimilitude with spatial short-term memory skills in real life. In addition, we evaluated the ARSM task's usability and perceived satisfaction. The study revealed that the younger children were more satisfied with the ARSM task. This novel instrument could be useful in detecting visuospatial short-term difficulties that affect specific developmental navigational disorders and/or school academic achievement.