Representation of survey and route spatial descriptions in children with nonverbal (visuospatial) learning disabilities

Weak central coherence in neurodevelopmental disorders: a comparative study

Introduction

Central coherence is the normal tendency to process and give meaning to incoming information taking into account the context or global view of that information.

Methods

We assessed the central coherence of 252 school children of normal intelligence between 6 and 11 years old. We compared the performance of two groups: (a) a control group (n = 194), and (b) a clinical group (n = 58) comprising children with NVLD+ADHD (n = 24), ADHD alone (n = 16), SCD (n = 8) and level-1ASD (n = 10) (Kluskall-Wallis H and Mann-Whitney U were calculated to make comparisons within groups and between pairs of groups). The effects of medication were studied (Student's t test).

Results

The NVLD+ADHD, SCD and ASD1 groups showed weak central coherence. The performance of the ADHD group was normal and differed significantly from the NVLD+ADHD group.

Conclusion

Central coherence deficit was not exclusive to ASD1: it also characterizes NVLD and SCD.

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.

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.

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.

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.

Personality, Behavior Characteristics, and Life Quality Impact of Children with Dyslexia

Dyslexia is one of the most common neurobehavioral disorders. Children with dyslexia usually suffer from negative, behavior personality problems, and impacted life quality. We aimed to identify family environment factors for dyslexia, and to evaluate the personality, behavior characteristics and life quality of children with dyslexia. A total of 60 children diagnosed with dyslexia and 180 normal children that were aged 7-12 who speak Chinese were recruited from four primary schools in Shantou City, China. Self-designed questionnaire, children's edition of the Eysenck Personality Questionnaire (EPQ), Conners' Parent Rating Scale (CPRS), and Quality of Life scale for children and adolescents (QLSCA) were employed for investigation. Multiple logistic regressions show that antenatal training (OR = 0.36), higher household income, higher parents' educational levels, and parents engaging in white-collar jobs were negatively associated with dyslexia; while, family members also suffering from dyslexia (OR = 12.17), lower frequency of communication between parents and children, and worse parent-child relationship were positively associated with dyslexia. Children with dyslexia scored higher in psychoticism and neuroticism (p = 0.040, 0.008), but lower in extroversion and dissimulation than normal children (p = 0.025, 0.007) in the EPQ test. They tended to be more introversion (68.3% vs. 43.0%), psychoticism (25.0% vs. 13.3%), and neuroticism (46.7% vs. 18.8%) than the controls. In addition, children with dyslexia had higher scores in conduct problem, learning problem, hyperactivity, and Conners' index of hyperactivity (CIH) in CPRS test; and, lower scores of psychosocial function, physical and mental health, and satisfaction of living quality in QLSCA test (all p < 0.05). Several family environment and parenting factors were associated with children's dyslexia significantly. Children with dyslexia had the personality of psychoticism, neuroticism, introversion, and more behavioral problems. Dyslexia significantly impacted the children's quality of life. Our findings provide multiple perspectives for early intervention of dyslexia in children, particularly in family factors and the parenting environment.

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.

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.

Visuo-spatial knowledge acquisition in individuals with Down syndrome: The role of descriptions and sketch maps

Few studies on individuals with Down syndrome (DS) have explored how they learn space. The present study examines space learning from verbal descriptions in individuals with DS, and explores the role of external cues (such as a sketch map). Twenty-eight individuals with DS and 28 matched typically-developing (TD) children listened to route or survey descriptions with or without seeing a corresponding sketch map (Description+Sketch Map [D+SM] and Description alone [D], respectively). After hearing each description, they performed tasks that involved recognizing, arranging sequentially, and locating landmarks. The results showed that individuals with DS performed less well in recognizing landmarks and arranging them sequentially. The D+SM condition produced general benefits in both groups' accuracy, though the improvement in locating landmarks was greater in the TD than in the DS group. In both groups, the D+SM condition prompted a better performance than the D condition when participants arranged landmarks sequentially after hearing a description from a route perspective, but not from a survey perspective. Overall, our results show that individuals with DS benefited when a spatial description was associated with a corresponding sketch map, albeit to a lesser degree than TD children. The findings are discussed in the light of the literature on DS and on spatial cognition in the TD domain.

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.

Anxiety and Depression in Children With Nonverbal Learning Disabilities, Reading Disabilities, or Typical Development

The main goal of the present study was to shed further light on the psychological characteristics of children with different learning disability profiles aged between 8 and 11 years, attending from third to sixth grade. Specifically, children with nonverbal learning disabilities (NLD), reading disabilities (RD), or a typical development (TD) were tested. In all, 15 children with NLD, 15 with RD, and 15 with TD were administered self-report questionnaires to assess different types of anxiety and depression symptoms. Both NLD and RD children reported experiencing more generalized and social anxiety than TD, the NLD children reported more severe anxiety about school and separation than TD, and the children with RD had worse depressive symptoms than those with NLD or TD.

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.

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.

Emotional false memories in children with learning disabilities

Research has shown that children with learning disabilities (LD) are less prone to evince associative illusions of memory as a result of impairments in their ability to engage in semantic processing. However, it is unclear whether this observation is true for scripted life events, especially if they include emotional content, or across a broad spectrum of learning disabilities. The present study addressed these issues by assessing recognition memory for script-like information in children with nonverbal learning disability (NLD), children with dyslexia, and typically developing children (N=51). Participants viewed photographs about 8 common events (e.g., family dinner), and embedded in each episode was either a negative or a neutral consequence of an unseen action. Children's memory was then tested on a yes/no recognition task that included old and new photographs. Results showed that the three groups performed similarly in recognizing target photographs, but exhibited differences in memory errors. Compared to other groups, children with NLD were more likely to falsely recognize photographs that depicted an unseen cause of an emotional seen event and associated more "Remember" responses to these errors. Children with dyslexia were equally likely to falsely recognize both unseen causes of seen photographs and photographs generally consistent with the script, whereas the other participant groups were more likely to falsely recognize unseen causes rather than script-consistent distractors. Results are interpreted in terms of mechanisms underlying false memories' formation in different clinical populations of children with LD.

Mental Representation of Spatial Information in Children with Non-Verbal and Reading Disabilities: Two Case Studies

Non-verbal learning disability (NLD) is a specific difficulty related to the processing of visuo-spatial material. The aim of the present study is to elucidate the profile of NLD as regards ability to process and comprehend spatial descriptions, through the analysis of individual cases. Our study examined one child with NLD (M.N.), plus a second child (G.B.) with reading disability (RD) for comparison. The two children had similar reading comprehension ability. They listened to two spatial descriptions, in both survey (i.e., bird's-eye view) and route (i.e., person's point of view) perspective, plus one non-spatial description. They then answered questions about the descriptions and relocated landmarks from the spatial descriptions on a map. Performance of the child with NLD was poor in spatial descriptions but good in the non-spatial description. In particular, task performance was poorer after survey description learning. Instead, G.B. performed well in both non-spatial and spatial (i.e., survey and route) descriptions. The NLD child was shown to be specifically impaired in ability to mentally represent spatial information in survey perspective.

Nonverbal learning disabilities: a critical review

This article presents a critical review of the term and concept of nonverbal learning disability (NLD). After a brief historical introduction, the article focuses on the apparent rarity of NLD; the hypothesis of the frequent co-occurrence of emotional disorder, depression, and suicide in NLD; the white matter hypothesis as an explanation of the origin of NLD; and the question of NLD as part of a variety of other disorders. It is argued that NLD presents a broad hypothesis, but that there is little evidence to support its use in clinical practice.

The cognitive phenotype of spina bifida meningomyelocele

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