Classification rules for basic phonological processing disabilities and nonverbal learning disabilities: formulation and external validity

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.

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.

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.

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.

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.

Pediatric epilepsy and comorbid reading disorders, math disorders, or autism spectrum disorders: Impact of epilepsy on cognitive patterns

INTRODUCTION

In pediatric epilepsy, comorbidities are reported to be frequent. The present study focusedon the cognitive patterns of children with isolated epilepsy, children with isolated neurodevelopmental disorders (reading disorders, math disorders, autism spectrum disorders), and children with epilepsy and these neurodevelopmental disorders as comorbidities.

METHODS

Based on two samples of referred children, one with epilepsy, reading disorders, math disorders, or ASDs occurring in "isolation" (n=117) and one with reading disorders, math disorders, and ASDs occurring comorbid with epilepsy (n=171), cognitive patterns were compared. The patterns displayed by verbal and nonverbal abilities from the WISC series were studied with repeated measures ANOVA. Thereafter, an exploratory 2∗3∗2 factorial analysis was done to study the independent contribution of the type of comorbidity and of the presence or absence of epilepsy to the VIQ-PIQ pattern.

RESULTS

In isolated epilepsy, a VIQ>PIQ pattern was found, which was not seen in the other disorders. When epilepsy and another disorder co-occurred, patterns were altered. They resembled partly the pattern seen in isolated epilepsy and partly the pattern seen in the isolated neurodevelopmental disorder. In comorbid reading disorders, the VIQ>PIQ pattern was mitigated; in comorbid math disorders, it was exacerbated. In comorbid ASDs, no clear pattern emerged. In the presence of epilepsy, patterns characteristic of isolated disorders appeared systematically shifted toward relatively lowered performance abilities or relatively spared verbal abilities. The similar "impact" exerted by epilepsy on the patterns of the various conditions suggested shared mechanisms.

Applicability of the nonverbal learning disability paradigm for children with 22q11.2 deletion syndrome

Chromosome 22qll.2 deletion syndrome (22qllDS) is the most common microdeletion in humans. Nonverbal learning disability (NLD) has been used to describe the strengths and deficits of children with 22q11DS, but the applicability of the label for this population has seldom been systematically evaluated. The goal of the current study was to address how well the NLD diagnosis characterizes children and adolescents with 22q11DS. A total of 74 children and adolescents with 22q11DS were given neurocognitive, socioemotional, and academic assessments to measure aspects of NLD. Of the cohort, 20% met at least 7 of 9 assessed criteria for NLD; 25% showed verbal skills exceeding their nonverbal skills as assessed by an IQ test; and 24% showed the good rote verbal capacity commonly associated with NLD. Hypothesizing that if the entire cohort did not show consistent NLD characteristics, the descriptor might be more accurate for a distinct subgroup, the authors used latent class analysis to divide participants into three subgroups. However, the lines along which the groups broke out were more related to general functioning level than to NLD criteria. All three groups showed a heightened risk for psychiatric illness, highlighting the importance of careful mental health monitoring for all children with 22qllDS.

Nonverbal learning disability

Nonverbal learning disability (NLD) is described as a subtype of specific learning disability where the source of the disability is a difficulty in processing nonverbal information. The child with NLD presents with problems in visual, spatial, and tactile perception but with strengths in rote verbal skills. Traditionally, these children were recognized by their difficulties in arithmetic which presented a stark contrast with their strengths in spelling and decoding text. They also exhibited a split between their verbal IQ (VIQ) and performance IQ (PIQ) scores with the VIQ being significantly higher than PIQ. Over time, however, diagnostic criteria have evolved and the broadened definition of the NLD syndrome has led many to question the utility and uniqueness of the NLD diagnosis. In addition, shifting diagnostic standards have made research results difficult to replicate. In short, the research to date leaves many unanswered questions about (1) the definition of the NLD syndrome, (2) the pervasiveness of the academic, social and psychopathological difficulties, (3) the source of the NLD syndrome, and (4) the degree to which it overlaps with other conditions. This chapter outlines a brief history of the NLD syndrome, how it is currently conceptualized, and some of the current debate about the unanswered questions above.

A Model to Guide the Conceptualization, Assessment, and Diagnosis of Nonverbal Learning Disorder

Although many learning disability types are formally recognized in major classification systems such as DSM-IV-TR and ICD-10, Nonverbal Learning Disorder (NLD) is not despite over 40 years of literature addressing its theoretical and neuropsychological foundation, its major features, and the methods by which to assess and diagnose it. Currently, there is no general agreement regarding the defining features of NLD and their relationship to daily functioning. Presented here is a description of NLD in the context of a model aimed at providing a standard language and framework for describing health and health-related states: the International Classification of Functioning, Disability and Health (ICF). It is proposed that the ICF model can guide clinical thinking, professional practice—including assessment, diagnosis, and treatment—and research with respect to NLD, eventually leading to the inclusion of NLD in formal classification systems.

Nonverbal and verbal learning: a comparative study of children and adolescents with 22q11 deletion syndrome, non-syndromal Nonverbal Learning Disorder and memory disorder

The 22q11 deletion syndrome (DS) is a common genetic disorder, and a Nonverbal Learning Disorder (NLD) is considered as a predominant part of the phenotype. The focus of our study was to investigate the role of learning in this NLD characteristic. We compared results of children and adolescents with 22q11 DS; with non-syndromal NLD and with memory disorders on multi-trial verbal and nonverbal learning tests. Better verbal and worse nonverbal IQs were significantly discrepant for the 22q11 DS sample and for the NLD sample; the memory sample had a FS-IQ in the normal range with lower verbal IQ. General IQ was lowest for the 22q11 DS group. Similar differences in normal verbal and worse nonverbal learning resulted for the 22q11 sample and NLD-sample, while memory sample showed low performances on both tasks. Error analysis in the visual learning task indicated that lacking integration of visual-spatial information affected impaired visual memory performances in 22q11 DS and NLD. Our results reflected a common neurological basis with visual-spatial and visual memory deficits in NLD and in the 22q11 DS sample. To further investigate the issue of cross modal novelty learning deficits we recommend the use of abstract verbal learning material.

Cognitive profile of adolescents with math disabilities: are the profiles different from those with reading disabilities?

Adolescents (ages 14-17) with math disabilities (MD, n=12), reading disabilities (RD, n=19), math+reading disabilities (MD+RD, n=12), and average achievers (n=15) were compared on measures of visual-spatial processing, random generation (inhibition), writing speed, short-term memory (STM), and working memory (WM). Adolescents with MD performed significantly lower than adolescents with RD on measures of visual-spatial processing and visual WM. Adolescents with MD outperformed adolescents with RD +MD on measures of random generation and motor speed. Performance of all three low-achieving groups was inferior to average achievers on measures of random generation, motor speed, and verbal WM. The results were interpreted within a multicomponent model that attributed deficits related to MD in adolescents to deficits related the visual-spatial sketchpad of WM.

Imaginative Representations of Two - and Three-Dimensional Matrices in Children with Nonverbal Learning Disabilities

Children with non-verbal learning disabilities (NLD) are characterized by high verbal and poor non-verbal intelligence, poor cognitive abilities, school difficulties, and—sometimes—depressive symptoms. NLD children lack visuospatial working memory, but it is not clear whether they encounter difficulties in mental imagery tasks. In the present study, NLD adolescents without depressive symptoms, depressed adolescents without NLD symptoms, and a control group were administered a mental imagery task requiring them to imagine to move along the cells of a 2-D (5 × 5) or 3-D (3 × 3 × 3) matrix. Results showed that NLD adolescents had difficulty at performing the imagery task when a 3-D pattern was involved. It is suggested that 3-D mental imagery tasks tap visuospatial processes which are weak in NLD individuals. In addition, their poor cognitive performance cannot be attributed to a depressive state, as the depressed group had a performance similar to that of controls.

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.

Social cognition and its relation to psychosocial adjustment in children with nonverbal learning disabilities

The current study examined social cognitive skills in children with nonverbal learning disabilities (NLD) compared to normally achieving (NA) children. The relation between social cognitive skills and psychosocial adjustment was also investigated. There were no group differences on children's ability to represent orally presented social vignettes. Children with NLD were less able to recognize self-generated competent/assertive responses as the best solutions to a problem, expected fewer positive and more negative outcomes for examiner-provided competent responses, and showed a trend toward more frequently judging a story character as being mean. A social problem solving factor predicted unique variance in psychosocial adjustment beyond variance accounted for by nonverbal intelligence and nonverbal social cue interpretation. Results are discussed within a framework for which social cognitive deficits more broadly defined than encoding and interpreting nonverbal social cues contribute to the psychosocial adjustment problems of children with NLD.

Perceptual organization, phonological awareness, and reading comprehension in adults with and without learning disabilities

It is not clear from research whether, or to what extent, reading comprehension is impaired in adults who have learning disabilities (LD). The influence of perceptual organization (PO) and phonological awareness (PA) on reading comprehension was investigated. PO and PA are cognitive functions that have been examined in previous research for their roles in nonverbal LD and phonological dyslexia, respectively. Nonverbal tests of PO and non-reading tests of PA were administered to a sample of adults with postsecondary education. Approximately two thirds of the sample had previously been diagnosed as having LD. In a multiple regression analysis, tests of PO and PA were used to predict scores for tests of reading comprehension and mechanics. Despite the nonverbal nature of the perceptual organizational test stimuli, PO strongly predicted reading comprehension. Tests of PA predicted decoding and reading speed. Results were interpreted as supporting the hypothesis that integrative processes usually characterized as nonverbal were nonetheless used by readers with and without disabilities to understand text. The study's findings have implications for understanding the reading of adults with learning disabilities, and the nature of reading comprehension in general.

Neuropsychological differences among children with Asperger syndrome, nonverbal learning disabilities, attention deficit disorder, and controls

Confusion is present as to possible diagnostic differences between Asperger syndrome (AS) and Nonverbal learning disabilities (NLD) and the relation of these disorders to attentional difficulties. Three-hundred and forty-five children participated in this study in 5 groups; NLD, AS, attention deficit hyperactivity disorder (ADHD): Combined type, ADHD: Inattentive type, and controls. The NLD group showed particular difficulty on visual-spatial, visual-motor, and fluid reasoning measures compared to the other groups. There was also a significant verbal-performance IQ split in this group related to difficulty in social functioning. This study extends the findings from previous studies and extends these findings to differences between AS and NLD groups.

An investigation into early acquired dyslexia

There are several group and case studies that investigate developmental dyslexia in children, and acquired and developmental reading disabilities in adults. To date however, there are few detailed investigations on cases of early acquired dyslexia. The purpose of this study was to examine such a case (participant referred to as SP). The goals of this investigation were to compare SP's reading impairments to the major subtypes of dyslexia, establish SP's specific reading deficits, and consider the neuropsychological variables that may impact on SP's reading disability.

Factor Structure of the Norwegian Version of the WAIS-III in a Clinical Sample

Confirmatory Factor Analyses (CFA) of the Wechsler Adult Intelligence Scale—III (WAIS-III) lend partial support to the four-factor model proposed in the test manual. However, the Arithmetic subtest has been especially difficult to allocate to one factor. Using the new Norwegian WAIS-III version, we tested factor models differing in the number of factors and in the placement of the Arithmetic subtest in a mixed clinical sample ( n = 272). Only the four-factor solutions had adequate goodness-of-fit values. Allowing Arithmetic to load on both the Verbal Comprehension and Working Memory factors provided a more parsimonious solution compared to considering the subtest only as a measure of Working Memory. Effects of education were particularly high for both the Verbal Comprehension tests and Arithmetic.

Is neuropsychology a psychosocial science?

Many early investigators of brain-behavior relationships focused their investigative efforts on the psychiatric implications of brain damage and dysfunction. Descriptions of emotional dyscontrol and other psychosocial difficulties appeared frequently in their writings. Although dimensions of perception, memory, and cognition dominate the current neuropsychological literature, the psychosocial implications of patterns of neuropsychological assets and deficits retain their importance (e.g., in the study of the dementing diseases of adulthood). Our investigations of brain-behavior relationships and their impact on psychosocial functioning have attempted to expand upon and chart a somewhat different (subtypal) course for this area of study. One clearly evident conclusion of these efforts is that neuropsychology is a psychosocial science. Some implications of our findings for research and clinical practice are outlined.

Do individuals with high functioning autism have the IQ profile associated with nonverbal learning disability?

Previously researchers have noted a high level of occurrence of the IQ profile associated with nonverbal learning disability (NLD) in Asperger syndrome (ASP) but not in high functioning autism (HFA). We examined the IQ profile scores of a large sample of children (n = 69) and adults (n = 77) with HFA, stringently diagnosed according to ADOS, ADI-R, and DSM-IV criteria, and a corresponding sample of typical child (n = 72) and adult controls (n = 107). At least one of the three primary components of the Wechsler pattern seen in NLD were found in 17-26% of the children and 20-32% of the adults with HFA. All three components occurred in slightly more than 5% of the children and adults with autism. Overall, the VIQ > PIQ profile seen in NLD occurred in 18% of the sample of individuals stringently diagnosed with HFA. Therefore, obtaining this IQ profile is not a valid clinical discriminator between NLD and HFA.

Do weak phonological representations impact on arithmetic development? A review of research into arithmetic and dyslexia

We review significant empirical studies of the arithmetic abilities of children with dyslexia. These studies suggest that the academic impairments of children with dyslexia are not limited to reading and spelling, but also include aspects of mathematics. A consistent finding across a number of studies is that children with dyslexia have difficulty recalling number facts. The results of the reviewed studies are analysed, both in terms of the weak phonological representations hypothesis, and the triple-code theory of mathematical cognition. It is suggested that the phonological processing deficits of individuals with dyslexia impair aspects of mathematics that rely on the manipulation of verbal codes (e.g. counting speed, number fact recall), whilst other aspects of mathematics that are less reliant on verbal codes (e.g. estimation, subitising) are unimpaired. Suggestions for testing this hypothesis are put forward.

Nichtsprachliche Lernstörung: Eine unspezifische oder richtungsweisende Klassifikation?

Die nichtsprachliche Lernstörung stellt eine Subgruppe von Lernstörungen dar, die in Kanada und den USA in der praktischen Arbeit mit Kindern einen wichtigen Platz eingenommen hat. Die nichtsprachliche Lernstörung umfasst verschiedene kognitive Defizite, die sich primär auf visuelle und taktile Schwierigkeiten beziehen, aber auch Beeinträchtigungen in der Flexibilität des Denkens und der Psychomotorik berücksichtigen. Durch die Verwendung dieser Klassifikation ist es möglich, eine Gruppe von lerngestörten Kindern zu beachten, die in den internationalen Klassifikationsrichtlinien keine Entsprechung finden. Die Entwicklung, die Ursachen und die Diagnostik dieser Störung werden vorgestellt und kritisch beleuchtet. Der Nutzen dieser Klassifikation wird hinterfragt und auf der Basis aktueller diagnostischer Anforderungen diskutiert. Vorschläge für die Weiterentwicklung und Anpassung der Klassifikation an deutsche Standards werden vorgenommen.

The influence of instruction modality on brain activation in teenagers with nonverbal learning disabilities: two case histories

Teenagers with nonverbal learning disabilities (NLD) have difficulty with fine-motor coordination, which may relate to the novelty of the task or the lack of "self-talk" to mediate action. In this study, we required two teenagers with NLD and two control group teenagers to touch the thumb of each hand firmly and accurately to the fingertips of the same hand, in an order specified by verbal or tactile instruction. Brain activity patterns (measured using functional magnetic resonance imaging) suggest that unlike control participants, the NLD participants used internalized speech to facilitate the novel task only when instructions were verbal. NLD participants also showed activity in a more widely distributed network of neural structures. These findings provide preliminary evidence for remediation strategies that encourage internal speech.

Russell-Silver Syndrome and Nonverbal Learning Disability: A Case Study

Russell-Silver Syndrome (RSS) is a rare genetic developmental disorder characterized by prenatal and postnatal growth delays and other physical abnormalities. Neuropsychological screening was completed with LP, a 20-year-old college male diagnosed at one year of age with Russell-Silver Syndrome. LP's history and test findings yielded a profile consistent with a nonverbal learning disability, with significantly higher verbal compared to nonverbal intelligence, deficient visual-spatial memory, fine motor coordination and motor planning problems, relatively greater difficulty in math compared to other achievement areas, decreased writing fluency, and social behavior impediments. LP also experienced attention and concentration problems along with a ruminative cognitive-emotional style and mild depression. His pattern of processing weaknesses indicated a need for academic accommodations to complete his college-level academic work, along with counseling to address emotional issues. Further studies of individuals with RSS should consider neuropsychological assessment to address patterns of cognitive processing and possible need for educational and psychosocial intervention.

Taxonicity of nonverbal learning disabilities in spina bifida

As currently defined, it is not clear whether Nonverbal Learning Disabilities (NLD) should be considered a matter of kind or magnitude (Meehl, 1995). The taxonicity of NLD, or the degree to which it is best construed as discrete versus continuous, has not been investigated using methods devised for this purpose. Latent Class Analysis (LCA) is a method for finding subtypes of latent classes from multivariate categorical data. This study represents an application of LCA on a sample of children and adolescents with spina bifida myelomeningocele (SBM) (N = 44), those presenting with features of NLD (N = 28) but no medical condition, and control volunteers (N = 44). The two-class solution provided evidence for the presence of a taxon with an estimated base-rate in the SBM group of .57. Indicator validities (the conditional probabilities of indicator endorsement in each latent class) suggest a somewhat different priority for defining NLD than is typically used by researchers investigating this disorder. A high degree of correspondence between LCA classifications and those based on a more conventional algorithm provided evidence for the validity of this approach.

Auditory Processing Disorder in Children Diagnosed With Nonverbal Learning Disability

Purpose

To determine whether children with a nonverbal learning disability (NVLD) have a higher incidence of auditory processing disorder (APD), especially in the tolerance-fading memory type of APD, and what associations could be found between performance on neuropsychological, intellectual, memory, and academic measures and APD.

Method

Eighteen children with NVLD ranging in age from 6 to 18 years received a central auditory processing test battery to determine incidence and subtype of APD. Psychological measures for assessment of NVLD included the Wechsler Scales, Wide Range Assessment of Memory and Learning, and Wechsler Individual Achievement Test. Neuropsychological measures included the Category Test, Trails A and B, the Tactual Performance Test, Grooved Pegs, and the Speech Sounds Perception Test. Neuropsychological test scores of the NVLD+APD and NVLD groups were compared using analysis of covariance procedures, with Verbal IQ and Performance IQ as covariates.

Results

Sixty-one percent of the children were diagnosed with APD, primarily in the tolerance-fading memory subtype. The group of children with APD and NVLD had significantly lower scores on Verbal IQ, Digit Span, Sentence Memory, Block Design, and Speech Sounds Perception than children without APD. An ancillary finding was that the incidence of attention deficit/hyperactivity disorder was significantly higher in children with NVLD (with and without APD) than in the general population.

Conclusion

The results indicate that children with NVLD are at risk for APD and that there are several indicators on neuropsychological assessment suggestive of APD. Collaborative, interdisciplinary evaluation of children with learning disorders is needed in order to provide effective therapeutic interventions.

Evidence for a double dissociation between spatial-simultaneous and spatial-sequential working memory in visuospatial (nonverbal) learning disabled children

The paper describes the performance of three children with specific visuospatial working memory (VSWM) impairments (Study 1) and three children with visuospatial (nonverbal) learning disabilities (Study 2) assessed with a battery of working memory (WM) tests and with a number of school achievement tasks. Overall, performance on WM tests provides evidence of a double dissociation between spatial-simultaneous processes, underpinning the memorization item positioning in a spatial configuration, and spatial-sequential processes, which allow memorization of the presentation order. In both groups of children of the two studies, a selective impairment either on spatial-sequential or on spatial-simultaneous working memory tasks was observed. These data support the existence of -simultaneous and -sequential modality-dependent processes in visuospatial working memory and confirm the importance of distinguishing between different subtypes of visuospatial (nonverbal) learning-disabled children.

Difficulties in the control of irrelevant visuospatial information in children with visuospatial learning disabilities

This research tested the hypothesis that children's difficulties in visuospatial working memory (VSWM) may mirror difficulties found with verbal working memory tasks in other categories of children. Two experiments compared the number of correct responses and errors in groups of visuospatial learning disabled children (VSLD) and Controls who were engaged in an active task testing visuospatial working memory. Children were presented with sequences of positions on a 4x4 matrix and were subsequently asked to remember only the last position of each series. In the first Experiment, VSLD children showed greater difficulty in both recalling the last positions and avoiding the irrelevant non-final positions compared with Controls. In the second experiment children of different age groups (second-graders and fifth-graders) were also required to stress, by tapping on the table, the irrelevant positions whenever the experimenter pointed to a coloured cell. Results showed that the number of errors was greater in the VSLD children, and the pattern of errors differed with their grade. In particular, the increased activation of stressed locations produced an increase of correct responses, and a decrease of intrusion errors, except in the case of VSLD second-graders, who made a higher number of intrusions for stressed than for unstressed locations. Results confirm that children with VSLD show a specific deficit in active VSWM, and in particular, in the ability to avoid intrusion errors. In general, the control of irrelevant information appears critical for a successful use of VSWM.

Narrative comprehension and retelling abilities of children with nonverbal learning disabilities

Nonverbal learning disabilities (NLD) are characterized by weaknesses in narrative discourse. Thirty-three children (M ag e= 11.7 years), 15 girls and 18 boys, listened to stories to evaluate their narrative comprehension and retelling abilities. Children with NLD (n = 11) performed as poorly as children with verbal impairment (n = 10) on all narrative measures. Compared to typical controls (n = 12), the NLD group was poorer in comprehending inferences, but not facts. They included less of the original content than controls in their story retells, and there were strong trends suggesting fewer utterances and less variety in their vocabulary usage. Results are discussed regarding their implications for understanding the neuropsychological profile of NLD.

Neuropsychological characteristics of juvenile delinquency

Knowledge of the neuropsychological characteristics related to JD and other behavioral disturbances in childhood is an important aspect of pediatric care. Referral of patients with developing behavioral problems for neuropsychological evaluation may assist pediatricians with identifying neuropsychological risk factors for JD, clarifying differential diagnostic questions, providing information for the nature of intervention efforts, and providing useful predictive tools for long-term planning and outcome. Thus, referrals for neuropsychological evaluation should not occur solely within the context of a patient with known central nervous system compromise. Neuropsychological results may be of benefit with disorders wherein the precise brain-behavior relationship is unclear, such as with JD. Once a child's neuropsychological characteristics are known and evaluated from a behavioral risk standpoint, pediatricians will have information that is pivotal to asserting recommendations for modifications to the home and school environments, as well as for direct intervention and treatment. The direction of future neuropsychological research includes the early identification of children and adolescents with potential behavioral disturbance. Accurate early differential diagnosis and knowledge of neuropsychological risk factors help to achieve this goal. Neuropsychological research and knowledge assist with understanding the complexities of interactions between environmental vulnerabilities and neuropsychological risk factors, and can provide useful predictive and preventative information for pediatricians.