Exploring basic numerical capacities in children with difficulties in simple arithmetical achievement / Exploración de las capacidades numéricas básicas en niños con dificultades en el rendimiento en aritmética básica

Abstract Introduction: Current cognitive theories suggest that mathematical learning disabilities may be caused by a dysfunction in the ability to represent non-symbolic numerosity (non-symbolic skills), by impairments in the ability to associate symbolic numerical representations with the underlying analogic non-numerical magnitude representation (symbolic and numerical mapping skills), or by a combination of both deficits. The aim of this study was to contrast the number sense hypothesis and the access deficit hypothesis, to identify the possible origin of the varying degrees of arithmetical difficulties. Method: We compared the performance of children with very low arithmetic achievement (VLA), children with low arithmetical achievement (LA), and typically achieving peers (TA), in non-symbolic, symbolic and numerical mapping tasks. Intellectual capacity and working memory were also evaluated as control variables. The sample comprised 85 Chilean children (3rd to 6th grades) from the Public General Education System. Data were included in several covariance analyses to identify potentially different behavioural profiles between groups. Results: The results showed deficits in both non-symbolic numerosity processing and number-magnitude mapping skills in children with VLA, whereas children with LA exhibited deficits in numerical mapping tasks only. Conclusions: These findings support the hypothesis of impaired non-symbolic numerical representations as the cognitive foundation of severe arithmetical difficulties. Low arithmetical achievement, in contrast, seems to be better explained by defective numerical mapping skills, which fits the access deficit hypothesis. The results presented here provide new evidence regarding the cognitive mechanisms underlying the different behavioural profiles identified in children with varying degrees of arithmetical difficulties.

Resumen Introducción: Teorías cognitivas actuales sugieren que las dificultades en el aprendizaje de las matemáticas pueden ser causadas por una disfunción en la habilidad de representar las numerosidades no-simbólicas (habilidades no-simbólicas), por dificultades en la habilidad de asociar los números con representaciones analógicas, no-simbólicas, subyacentes a la magnitud (habilidades simbólicas y de mapeo) o por una combinación de ambos déficits. El objetivo de este estudio fue contrastar la hipótesis de un déficit en el sentido del número y la hipótesis del déficit en el acceso, para identificar el posible origen de los diferentes grados de dificultades en aritmética. Método: Se comparó el desempeño de niños con muy bajo rendimiento en aritmética (VLA), niños con bajo rendimiento en aritmética (LA) y pares con rendimiento típico (TA), en tareas numéricas no-simbólicas, simbólicas y de mapeo. También se evaluaron la capacidad intelectual y la memoria de trabajo como variables de control. La muestra estuvo conformada por 85 niños chilenos (de 3ero a 6to grado) del Sistema de General de Educación Pública. Los datos fueron incluidos en varios análisis de covarianza para identificar posibles perfiles conductuales diferentes entre grupos. Resultados: Los resultados mostraron que los niños con VLA tienen déficits tanto en el procesamiento no-simbólico de la numerosidad como en las habilidades de mapeo entre los símbolos numéricos y la magnitud analógica que estos representan. Los niños con LA solo mostraron déficits en las habilidades de mapeo. Conclusiones: Estos hallazgos sustentan la hipótesis de que un daño en las representaciones numéricas no-simbólicas subyace a las dificultades severas en aritmética. Por el contrario, el bajo rendimiento en aritmética parece explicarse por deficientes habilidades de mapeo, lo cual se ajusta mejor a la hipótesis del déficit en el acceso. Los anteriores resultados, ofrecen nuevas evidencias respecto a los mecanismos cognitivos que subyacen a los perfiles conductuales identificados en los niños con diferentes grados de dificultades en aritmética.

Numerical Processing Impairment in 22q11.2 (LCR22-4 to LCR22-5) Microdeletion: A Cognitive-Neuropsychological Case Study.

Although progress has been made, the cognitive, biological and, particularly, the genetic underpinnings of math learning difficulties (MD) remain largely unknown. This difficulty stems from the heterogeneity of MD and from the large contribution of environmental factors to its etiology. Understanding endophenotypes, e.g., the role of the Approximate Number System (ANS), may help understanding the nature of MD. MD associated with ANS impairments has been described in some genetic conditions, e.g., 22q11.2 deletion syndrome (22q11.2DS or Velocardiofacial syndrome, VCFS). Recently, a girl with MD was identified in a school population screening. She has a new syndrome resulting from a microdeletion in 22q11.2 (LCR22-4 to LCR22-5), a region adjacent to but not overlapping with region 22q11.2 (LCR22-2 to LCR22-4), typically deleted in VCFS. Here, we describe her cognitive-neuropsychological and numerical-cognitive profiles. The girl was assessed twice, at 8 and 11 years. Her numerical-cognitive performance at both times was compared to demographically similar girls with normal intelligence in a single-case, quasi-experimental study. Neuropsychological assessment was normal, except for relatively minor impairments in executive functions. She presented severe and persistent difficulties in the simplest single-digit calculations. Difficulties in commutative operations improved from the first to the second assessment. Difficulties in subtraction persisted and were severe. No difficulties were observed in Arabic number writing. Difficulties in single-digit calculation co-occurred with basic numerical processing impairments in symbolic and non-symbolic (single-digit comparison, dot sets size comparison and estimation) tasks. Her difficulties suggest ANS impairment. No difficulties were detected in visuospatial/visuoconstructional and in phonological processing tasks. The main contributions of the present study are: (a) this is the first characterization of the neuropsychological phenotype in 22q11.2DS (LCR22-4 to LCR22.5) with normal intelligence; (b) mild forms of specific genetic conditions contribute to persistent MD in otherwise typical persons; (c) heterogeneity of neurogenetic underpinnings of MD is suggested by poor performance in non-symbolic numerical processing, dissociated from visuospatial/visuoconstructional and phonological impairments; (d) similar to what happens in 22q11.2DS (LCR22-2 to LCR22-4), ANS impairments may also characterize 22q11.2DS (LCR22-4 to LCR22-5).

Nonverbal learning disabilities and developmental dyscalculia: Differential diagnosis of two Brazilian children / Transtornos de aprendizagem não verbal e discalculia do desenvolvimento: Diagnóstico diferencial de duas crianças brasileiras / Trastornos de aprendizaje no verbal y discalculia del desarrollo: Diagnóstico diferencial de dos niños brasileños

Nonverbal learning disabilities (NVLD), a clinical condition still little reported in Brazil, are characterized by damages in the visual spatial domains, visual motor integration, fine motor skills, math skills and social and emotional difficulties. Developmental Dyscalculia (DD) is a neurodevelopmental disorder that affects basic arithmetic skills acquisition, including storage and recovery of arithmetic facts, calculation fluency and precision and number sense domain. Although both are persistent Math learning disorder/disability, they cause different damages. The objective of this case report is to describe, compare and analyze the neuropsychological profile of two Brazilian children with similar complaints but distinct diagnosis.

Transtornos de aprendizagem não verbal (TANV), ainda pouco divulgado no Brasil, caracterizam-se por prejuízos nos domínios visuoespacial, integração visuomotora, motricidade fina, habilidades matemáticas e dificuldade social e emocional. Discalculia do Desenvolvimento (DD) é um transtorno do neurodesenvolvimento, com prejuízo na aquisição de habilidades aritméticas básicas, incluindo armazenagem e recuperação de fatos aritméticos, fluência e precisão de cálculo, e domínio do senso numérico. Apesar de ambos serem um transtorno persistente de aprendizagem matemática, envolvem prejuízos diferentes. Este relato de caso tem o objetivo de descrever, comparar e analisar o perfil neuropsicológico de duas crianças brasileiras, com queixa similar, e diagnóstico distinto.

Trastornos de aprendizaje no verbal (TANV), aún poco divulgado en Brasil, se caracteriza por perjuicios en los dominios visuoespacial, integración visomotora, motricidad fina, habilidades matemáticas y dificultades social y emocional. Discalculia del Desarrollo (DD) es un trastorno del desarrollo neural, con perjuicio en la adquisición de habilidades aritméticas básicas, incluyendo almacenaje y recuperación de hechos aritméticos, fluidez y precisión de cálculo y dominio del sentido numérico. Pese a que ambos sean trastornos persistentes de aprendizaje de matemáticas, son perjuicios diferentes. Este relato de experiencia tiene el objetivo de describir, comparar y analizar el perfil neuropsicológico de dos niños brasileños, con queja similar, y diagnóstico distinto.

Stable measures of number sense accuracy in math learning disability: Is it time to proceed from basic science to clinical application?

Math learning disability (MLD) or developmental dyscalculia is a highly prevalent and persistent difficulty in learning arithmetic that may be explained by different cognitive mechanisms. The accuracy of the number sense has been implicated by some evidence as a core deficit in MLD. However, research on this topic has been mainly conducted in demographically selected samples, using arbitrary cut-off scores to characterize MLD. The clinical relevance of the association between number sense and MLD remains to be investigated. In this study, we aimed at assessing the stability of a number sense accuracy measure (w) across five experimental sessions, in two clinically defined cases of MLD. Stable measures of number sense accuracy estimate are required to clinically characterize subtypes of MLD and to make theoretical inferences regarding the underlying cognitive mechanisms. G. A. was a 10-year-old boy with MLD in the context of dyslexia and phonological processing impairment and his performance remained steadily in the typical scores range. The performance of H. V., a 9-year-old girl with MLD associated with number sense inaccuracy, remained consistently impaired across measurements, with a nonsignificant tendency to worsen. Qualitatively, H. V.'s performance was also characterized by greater variability across sessions. Concomitant clinical observations suggested that H. V.'s difficulties could be aggravated by developing symptoms of mathematics anxiety. Results in these two cases are in line with the hypotheses that at least two reliable patterns of cognitive impairment may underlie math learning difficulties in MLD, one related to number sense inaccuracy and the other to phonological processing impairment. Additionally, it indicates the need for more translational research in order to examine the usefulness and validity of theoretical advances in numerical cognition to the clinical neuropsychological practice with MLD.

Cognição numérica em crianças com transtornos específicos de aprendizagem / Numerical cognition in children with specific learning disabilities / Cognición numérica en niños con trastornos específicos de aprendizaje

O objetivo do presente estudo foi investigar o desenvolvimento de sistemas específicos da Cognição Numérica (Senso Numérico - SN, Compreensão Numérica - CN, Produção Numérica - PN e Cálculo - CA) em crianças brasileiras com Transtornos Específicos de Aprendizagem. Participaram do estudo 72 crianças (36 meninos), entre 9 e 10 anos, cursando os 4º ou 5º Anos do Ensino Fundamental em escolas públicas da região centro-oeste do Estado de São Paulo, Brasil; divididas em três grupos: controle (CT, N=42), com perfil de Dislexia do Desenvolvimento (DL, N = 11) e com perfil de Discalculia do Desenvolvimento combinada com dislexia (DDc, N = 19). Todas apresentavam nível intelectual médio para faixa etária. Os Transtornos Específicos de Aprendizagem foram aferidos pelo Teste de Desempenho Escolar (Stein, 1994), no qual as crianças com DDc obtiveram necessariamente classificação 'inferior' no Teste de Aritmética. Os três grupos foram similares em SN. As crianças DL e DDc apresentaram prejuízos leves em CN. Contudo, crianças com DDc apresentaram prejuízos moderados em PN e de leve a moderado em CA, o que indica um comprometimento mais generalizado em Cognição Numérica quando comparadas aos outros grupos. Em conclusão, crianças com DDc apresentaram maiores prejuízos e defasagem em relação às crianças DL e com desenvolvimento típico nos diferentes sistemas da Cognição Numérica.

The aim of this study was to investigate the development of specific domains of Numerical Cognition (Number Sense - NS, Number Comprehension - NC, Number Production - NP, and Calculation - CA) in Brazilian children with Specific Learning Disorders. The study included 72 children (36 boys), from 9-to 10-years-old, enrolled in 4th and 5th years of elementary school of public schools at countryside of Sao Paulo State, Brazil. They were divided into three groups: control (CT, N = 42), Developmental Dyslexia (DL, N = 11) and Developmental Dyscalculia combined with dyslexia (DDc, N = 19). All participants had intellectual level within the normal range, however, children from the last two groups had Learning Disorders classified by School Achievement Test - TDE (Stein, 1994) and DDc children received necessarily classification as 'inferior' in Arithmetic Test of TDE. The children did not differ in NS. DL and DDc children showed slight deficits in NC. However, DDc children had moderate in NP and mild to moderate deficits in CA, which indicates a more generalized impairment in Numerical Cognition. Furthermore, DDc children showed discrepancy in Numerical Cognition performance when compared to the other groups. Thus, children with Learning Disorders showed different performances in Numerical Cognition, although both groups had preserved SN, DDc children showed higher deficits and discrepancy in relation DL and typically developing children.

El objetivo de este estudio fue investigar el desarrollo de los sistemas específicos de la Cognición Numérica (el Sentido Numérico - SN, la comprensión numérica - CN, la producción numérica - PN y el Cálculo - CA) en niños brasileños con Trastornos Específicos de Aprendizaje. El estudio incluyó a 72 niños (36 chicos), con edad entre 9 y 10 años, estudiantes de los años 4to y 5to de primaria en escuelas públicas de un pueblo del Estado de São Paulo, Brasil; divididos en tres grupos: control (CT, N = 42), perfil de la Dislexia de Desarrollo (DL, N = 11) y el perfil de la Discalculia del Desarrollo combinado con dislexia (DDc, N = 19). Todos tenían el nivel intelectual dentro del rango medio. Los trastornos del aprendizajes e evaluaron a través de la Prueba de Rendimiento Académico (Stein, 1994), en el que los niños con DDc obtuvieron una clasificación necesariamente "inferior" en la prueba de aritmética. Los tres grupos fueron similares en SN. Los niños con DL y DDc mostraron ligeras pérdidas en CN. Sin embargo, los niños con DDc sufrieron daños moderados en PN y de leves a moderados en CA, por lo tanto, exhibieron un deterioro más generalizado en la cognición numérica en comparación a los otros grupos. En conclusión, los niños con DDc presentaron mayores perjuicios do que niños con DL o desarrollo típico de los diferentes sistemas de la Cognición Numérica.

Cognição numérica de crianças pré-escolares brasileiras pela ZAREKI-K / Numerical cognition in brazilian preschool children by the ZAREKI-K / Cognición numérica de niños preescolares brasileños por la ZAREKI-K

A Cognição Numérica é influenciada por fatores biológicos, cognitivos, educacionais e culturais. Constitui- se tanto de um sistema primário, chamado de Senso Numérico que seria inato e de abrangência universal, quanto de sistemas secundários, como o Cálculo que está implicado a realização de operações matemáticas por meio de símbolos ou palavras e o Processamento Numérico, que se divide em dois componentes, a Compreensão Numérica, que está relacionada ao entendimento de símbolos numéricos e a Produção Numérica: que inclui a leitura, escrita e contagem de números. Entretanto, os estudos que evidenciam o desenvolvimento destas funções em crianças de idade pré-escolar são escassos. Diante disso os objetivos do presente estudo foram investigar a cognição numérica em crianças brasileiras pré-escolares e demonstrar a validade de construto da ZAREKI-K (Bateria Neuropsicológica para Avaliação do Tratamento dos Números e do Cálculo para Crianças pré-escolares). Participaram da pesquisa 42 crianças, entre 5 e 6 anos de idade, de ambos os sexos, estudantes de escolas públicas de educação pré-escolar, que foram avaliadas pelos subtestes da ZAREKI-K e WISC-III. Os Resultados indicaram diferenças significativas associadas à idade em que crianças de 6 anos obtiveram melhores pontuações em subtestes relacionados a Produção numérica, Compreensão numérica e Cálculo, bem como correlações moderadas a fortes entre alguns subtestes de ambos os instrumentos, demonstrando a validade de constructo da bateria. Em conclusão, foram obtidos dados normativos preliminares para a ZAREKI-K, ademais as análises sugerem tratar-se de um instrumento promissor para a avaliação da cognição numérica em crianças pré-escolares.

The Numerical Cognition is influenced by biological, cognitive, educational and cultural factors. It consists of a primary system, called Number Sense that would be innate and universal, also of secondary systems: the Calculation, implied to perform mathematical operations by means of symbols or words and Number Processing, which is divided into two components, Number Comprehension, related with the understanding of numerical symbols and Number Production, which includes reading, writing and counting numbers. However, studies that show the development of these functions in children of preschool age are scarce. Therefore, aims of this study were to investigate numerical cognition in preschool Brazilian children to demonstrate the construct validity of the ZAREKI-K (A Neuropsychological Battery for the Assessment of Treatment of Numbers and Calculation for preschool children). The participants were 42 children of both genders, who attended public elementary schools; the children were evaluated by this battery and WISC-III. The results indicated significant differences associated with age which children of 6 years had better scores on subtests related to Number Production, Calculation and Number Comprehension, as well moderate and high correlations between some subtests of both instruments, demonstrating the construct validity of the battery. In conclusion, preliminary normative data were obtained for ZAREKI-K. The analyses suggested that it is a promising tool for the assessment of numerical cognition in preschool children.

La cognición numérica es influenciada por factores biológicos, educativos, cognitivos y culturales. Posee un sistema primario innato y universal, que es el Sentido Numérico y sistemas secundarios: el Cálculo, para realizar operaciones matemáticas por medio de símbolos o palabras y el Procesamiento Numérico, que se divide en dos componentes, la Comprensión Numérica, que implica la comprensión de los símbolos numéricos, y la Producción Numérica que incluye la lectura, escritura y conteo de números. Sin embargo, hay pocos estudios que muestran el desarrollo de estos sistemas en los niños de edad preescolar. Los objetivos de este estudio fueran investigar la cognición numérica en niños brasileños en edad preescolar y demostrar la validez de constructo de la ZAREKI-K (Batería Neuropsicológica para la Evaluación del Tratamiento de los Números y el Cálculo para los Niños en edad Preescolar; Weinhold-Zulauf, Schweiter, & von Aster, 2003). Los participantes fueron 42 niños de entre 5 y 6 años de edad, de ambos sexos, que estudiaban en escuelas públicas de educación preescolar, los niños fueron evaluados por la referida batería y la WISC-III. Los resultados indicaron que los niños de seis años presentaron mejores puntuaciones en las pruebas relacionadas con Producción Numérica, Cálculo y la Comprensión Numérica, así como las correlaciones altas y moderadas entre algunos subtest de ambos instrumentos, lo que demuestra la validez construirla batería. En conclusión, se obtuvieron datos preliminares normativos para el ZAREKI-K. Los análisis sugieren que este es un instrumento prometedor para la evaluación de la cognición numérica en niños preescolares.

Cognição numérica de crianças pré-escolares brasileiras pela ZAREKI-K / Numerical cognition in brazilian preschool children by the ZAREKI-K / Cognición numérica de niños preescolares brasileños por la ZAREKI-K

A Cognição Numérica é influenciada por fatores biológicos, cognitivos, educacionais e culturais. Constitui- se tanto de um sistema primário, chamado de Senso Numérico que seria inato e de abrangência universal, quanto de sistemas secundários, como o Cálculo que está implicado a realização de operações matemáticas por meio de símbolos ou palavras e o Processamento Numérico, que se divide em dois componentes, a Compreensão Numérica, que está relacionada ao entendimento de símbolos numéricos e a Produção Numérica: que inclui a leitura, escrita e contagem de números. Entretanto, os estudos que evidenciam o desenvolvimento destas funções em crianças de idade pré-escolar são escassos. Diante disso os objetivos do presente estudo foram investigar a cognição numérica em crianças brasileiras pré-escolares e demonstrar a validade de construto da ZAREKI-K (Bateria Neuropsicológica para Avaliação do Tratamento dos Números e do Cálculo para Crianças pré-escolares). Participaram da pesquisa 42 crianças, entre 5 e 6 anos de idade, de ambos os sexos, estudantes de escolas públicas de educação pré-escolar, que foram avaliadas pelos subtestes da ZAREKI-K e WISC-III. Os Resultados indicaram diferenças significativas associadas à idade em que crianças de 6 anos obtiveram melhores pontuações em subtestes relacionados a Produção numérica, Compreensão numérica e Cálculo, bem como correlações moderadas a fortes entre alguns subtestes de ambos os instrumentos, demonstrando a validade de constructo da bateria. Em conclusão, foram obtidos dados normativos preliminares para a ZAREKI-K, ademais as análises sugerem tratar-se de um instrumento promissor para a avaliação da cognição numérica em crianças pré-escolares.(AU).

The Numerical Cognition is influenced by biological, cognitive, educational and cultural factors. It consists of a primary system, called Number Sense that would be innate and universal, also of secondary systems: the Calculation, implied to perform mathematical operations by means of symbols or words and Number Processing, which is divided into two components, Number Comprehension, related with the understanding of numerical symbols and Number Production, which includes reading, writing and counting numbers. However, studies that show the development of these functions in children of preschool age are scarce. Therefore, aims of this study were to investigate numerical cognition in preschool Brazilian children to demonstrate the construct validity of the ZAREKI-K (A Neuropsychological Battery for the Assessment of Treatment of Numbers and Calculation for preschool children). The participants were 42 children of both genders, who attended public elementary schools; the children were evaluated by this battery and WISC-III. The results indicated significant differences associated with age which children of 6 years had better scores on subtests related to Number Production, Calculation and Number Comprehension, as well moderate and high correlations between some subtests of both instruments, demonstrating the construct validity of the battery. In conclusion, preliminary normative data were obtained for ZAREKI-K. The analyses suggested that it is a promising tool for the assessment of numerical cognition in preschool children.(AU).

La cognición numérica es influenciada por factores biológicos, educativos, cognitivos y culturales. Posee un sistema primario innato y universal, que es el Sentido Numérico y sistemas secundarios: el Cálculo, para realizar operaciones matemáticas por medio de símbolos o palabras y el Procesamiento Numérico, que se divide en dos componentes, la Comprensión Numérica, que implica la comprensión de los símbolos numéricos, y la Producción Numérica que incluye la lectura, escritura y conteo de números. Sin embargo, hay pocos estudios que muestran el desarrollo de estos sistemas en los niños de edad preescolar. Los objetivos de este estudio fueran investigar la cognición numérica en niños brasileños en edad preescolar y demostrar la validez de constructo de la ZAREKI-K (Batería Neuropsicológica para la Evaluación del Tratamiento de los Números y el Cálculo para los Niños en edad Preescolar; Weinhold-Zulauf, Schweiter, & von Aster, 2003). Los participantes fueron 42 niños de entre 5 y 6 años de edad, de ambos sexos, que estudiaban en escuelas públicas de educación preescolar, los niños fueron evaluados por la referida batería y la WISC-III. Los resultados indicaron que los niños de seis años presentaron mejores puntuaciones en las pruebas relacionadas con Producción Numérica, Cálculo y la Comprensión Numérica, así como las correlaciones altas y moderadas entre algunos subtest de ambos instrumentos, lo que demuestra la validez construirla batería. En conclusión, se obtuvieron datos preliminares normativos para el ZAREKI-K. Los análisis sugieren que este es un instrumento prometedor para la evaluación de la cognición numérica en niños preescolares.(AU).

Cognição numérica em crianças com transtornos específicos de aprendizagem / . Numerical cognition in children with specific learning disabilities / Cognición numérica en niños con trastornos específicos de aprendizaje

O objetivo do presente estudo foi investigar o desenvolvimento de sistemas específicos da Cognição Numérica (Senso Numérico - SN, Compreensão Numérica - CN, Produção Numérica - PN e Cálculo - CA) em crianças brasileiras com Transtornos Específicos de Aprendizagem. Participaram do estudo 72 crianças (36 meninos), entre 9 e 10 anos, cursando os 4º ou 5º Anos do Ensino Fundamental em escolas públicas da região centro-oeste do Estado de São Paulo, Brasil; divididas em três grupos: controle (CT, N=42), com perfil de Dislexia do Desenvolvimento (DL, N = 11) e com perfil de Discalculia do Desenvolvimento combinada com dislexia (DDc, N = 19). Todas apresentavam nível intelectual médio para faixa etária. Os Transtornos Específicos de Aprendizagem foram aferidos pelo Teste de Desempenho Escolar (Stein, 1994), no qual as crianças com DDc obtiveram necessariamente classificação 'inferior' no Teste de Aritmética. Os três grupos foram similares em SN. As crianças DL e DDc apresentaram prejuízos leves em CN. Contudo, crianças com DDc apresentaram prejuízos moderados em PN e de leve a moderado em CA, o que indica um comprometimento mais generalizado em Cognição Numérica quando comparadas aos outros grupos. Em conclusão, crianças com DDc apresentaram maiores prejuízos e defasagem em relação às crianças DL e com desenvolvimento típico nos diferentes sistemas da Cognição Numérica.(AU).

The aim of this study was to investigate the development of specific domains of Numerical Cognition (Number Sense - NS, Number Comprehension - NC, Number Production - NP, and Calculation - CA) in Brazilian children with Specific Learning Disorders. The study included 72 children (36 boys), from 9-to 10-years-old, enrolled in 4th and 5th years of elementary school of public schools at countryside of Sao Paulo State, Brazil. They were divided into three groups: control (CT, N = 42), Developmental Dyslexia (DL, N = 11) and Developmental Dyscalculia combined with dyslexia (DDc, N = 19). All participants had intellectual level within the normal range, however, children from the last two groups had Learning Disorders classified by School Achievement Test - TDE (Stein, 1994) and DDc children received necessarily classification as 'inferior' in Arithmetic Test of TDE. The children did not differ in NS. DL and DDc children showed slight deficits in NC. However, DDc children had moderate in NP and mild to moderate deficits in CA, which indicates a more generalized impairment in Numerical Cognition. Furthermore, DDc children showed discrepancy in Numerical Cognition performance when compared to the other groups. Thus, children with Learning Disorders showed different performances in Numerical Cognition, although both groups had preserved SN, DDc children showed higher deficits and discrepancy in relation DL and typically developing children.(AU).

El objetivo de este estudio fue investigar el desarrollo de los sistemas específicos de la Cognición Numérica (el Sentido Numérico - SN, la comprensión numérica - CN, la producción numérica - PN y el Cálculo - CA) en niños brasileños con Trastornos Específicos de Aprendizaje. El estudio incluyó a 72 niños (36 chicos), con edad entre 9 y 10 años, estudiantes de los años 4to y 5to de primaria en escuelas públicas de un pueblo del Estado de São Paulo, Brasil; divididos en tres grupos: control (CT, N = 42), perfil de la Dislexia de Desarrollo (DL, N = 11) y el perfil de la Discalculia del Desarrollo combinado con dislexia (DDc, N = 19). Todos tenían el nivel intelectual dentro del rango medio. Los trastornos del aprendizajes e evaluaron a través de la Prueba de Rendimiento Académico (Stein, 1994), en el que los niños con DDc obtuvieron una clasificación necesariamente "inferior" en la prueba de aritmética. Los tres grupos fueron similares en SN. Los niños con DL y DDc mostraron ligeras pérdidas en CN. Sin embargo, los niños con DDc sufrieron daños moderados en PN y de leves a moderados en CA, por lo tanto, exhibieron un deterioro más generalizado en la cognición numérica en comparación a los otros grupos. En conclusión, los niños con DDc presentaron mayores perjuicios do que niños con DL o desarrollo típico de los diferentes sistemas de la Cognición Numérica.(AU).

Are 22q11.2 distal deletions associated with math difficulties?

Approximately 6% of school-aged children have math difficulties (MD). A neurogenetic etiology has been suggested due to the presence of MD in some genetic syndromes such as 22q11.2DS. However, the contribution of 22q11.2DS to the MD phenotype has not yet been investigated. This is the first population-based study measuring the frequency of 22q11.2DS among school children with MD. Children (1,564) were identified in the schools through a screening test for language and math. Of these children, 152 (82 with MD and 70 controls) were selected for intelligence, general neuropsychological, and math cognitive assessments and for 22q11.2 microdeletion screening using MLPA. One child in the MD group had a 22q11.2 deletion spanning the LCR22-4 to LCR22-5 interval. This child was an 11-year-old girl with subtle anomalies, normal intelligence, MD attributable to number sense deficit, and difficulties in social interactions. Only 19 patients have been reported with this deletion. Upon reviewing these reports, we were able to characterize a new syndrome, 22q11.2 DS (LCR22-4 to LCR22-5), characterized by prematurity; pre- and postnatal growth restriction; apparent hypotelorism, short/upslanting palpebral fissures; hypoplastic nasal alae; pointed chin and nose; posteriorly rotated ears; congenital heart defects; skeletal abnormalities; developmental delay, particularly compromising the speech; learning disability (including MD, in one child); intellectual disability; and behavioral problems. These results suggest that 22q11.2 DS (LCR22-4 to LCR22-5) may be one of the genetic causes of MD.

Neurocognitive profiles of learning disabled children with neurofibromatosis type 1.

Neurofibromatosis 1 (NF1) is a genetic condition generally associated with intellectual deficiency and learning disabilities. Although there have been groundbreaking advances in the understanding of the molecular, cellular, and neural systems underlying learning deficits associated to NF1 in animal models, much remains to be learned about the spectrum of neurocognitive phenotype associated with the NF1 clinical syndrome. In the present study, 32 children with NF1 ranging from 7 to 14 years were evaluated with neurocognitive tests dedicated to assess basic capacities which are involved in reading and mathematical achievement. Deficits in lexical and phonological strategies and poor number facts retrieval were found underlying reading and arithmetic disorders, respectively. Additionally, efficiencies in lexical/phonological strategies and mental arithmetic were significant predictors of individual differences in reading attainment and math. However, deficits in core numeric capacities were not found in the sample, suggesting that it is not responsible for calculation dysfluency. The estimated prevalence of Developmental Dyscalculia was 18.8%, and the male:female ratio was 5:1. On the other hand, the prevalence of Developmental Dyslexia was almost 3 times as high (50%), and no gender differences were found (male: female ratio = 1:1). This study offers new evidence to the neurocognitive phenotype of NF1 contributing to an in depth understanding of this condition, but also to possible treatments for the cognitive deficits associated with NF1.

Discalculia do desenvolvimento: avaliação da representação numérica pela ZAREKI-R / Developmental dyscalculia: assessment of number representation by the ZAREKI-R

O presente estudo investigou aspectos da representação numérica (processamento numérico e cálculo) e memória operacional de crianças com transtornos de aprendizagem. Participaram 30 crianças de idade entre 9 e 10 anos, ambos os gêneros, divididas em dois grupos: sem dificuldade em aritmética (SDA; N=11) e com dificuldade em aritmética (CDA; N=19), avaliadas pela ZAREKI-R, Matrizes Coloridas de Raven, o Blocos de Corsi e o BCPR. Crianças CDA exibiram escores levemente mais baixos que as SDA quanto ao nível intelectual e nos Blocos de Corsi. Na ZAREKI-R apresentaram prejuízo nos subtestes ditado de números, cálculo mental, problemas aritméticos e total. Crianças CDA apresentaram déficits específicos em memória operacional visuoespacial e comprometimento em processamento numérico e cálculo, compatível com discalculia do desenvolvimento.

This study investigated which aspects of number processing and calculation and working memory are related to arithmetic deficits. The participants were children aged from 9 to 10 years, both gender, divided in two groups based on their calculation score: a group without arithmetic disability (SDA; N=11) and with arithmetic disability (CDA; N=19); assessed by the instruments: ZAREKI-R, Raven's Coloured Progressive Matrices, Block Span, Digit Span, and CPR (pseudowords repetition). CDA children exhibited slightly lower scores than SDA on intellectual level and Block Span, and deficits in dictation of numbers, mental calculation, and problem solving tasks of the ZAREKI-R. The results indicate that CDA children have specific deficits in visuospatial working memory and performed poorly in number representation tasks, which fulfill criteria for Developmental Dyscalculia.

Discalculia do desenvolvimento: avaliação da representação numérica pela ZAREKI-R / Developmental dyscalculia: assessment of number representation by the ZAREKI-R

O presente estudo investigou aspectos da representação numérica (processamento numérico e cálculo) e memória operacional de crianças com transtornos de aprendizagem. Participaram 30 crianças de idade entre 9 e 10 anos, ambos os gêneros, divididas em dois grupos: sem dificuldade em aritmética (SDA; N=11) e com dificuldade em aritmética (CDA; N=19), avaliadas pela ZAREKI-R, Matrizes Coloridas de Raven, o Blocos de Corsi e o BCPR. Crianças CDA exibiram escores levemente mais baixos que as SDA quanto ao nível intelectual e nos Blocos de Corsi. Na ZAREKI-R apresentaram prejuízo nos subtestes ditado de números, cálculo mental, problemas aritméticos e total. Crianças CDA apresentaram déficits específicos em memória operacional visuoespacial e comprometimento em processamento numérico e cálculo, compatível com discalculia do desenvolvimento.

This study investigated which aspects of number processing and calculation and working memory are related to arithmetic deficits. The participants were children aged from 9 to 10 years, both gender, divided in two groups based on their calculation score: a group without arithmetic disability (SDA; N=11) and with arithmetic disability (CDA; N=19); assessed by the instruments: ZAREKI-R, Raven's Coloured Progressive Matrices, Block Span, Digit Span, and BCPR (pseudowords repetition). CDA children exhibited slightly lower scores than SDA on intellectual level and Block Span, and deficits in dictation of numbers, mental calculation, and problem solving tasks of the ZAREKI-R. The results indicate that CDA children have specific deficits in visuospatial working memory and performed poorly in number representation tasks, which fulfill criteria for Developmental Dyscalculia.