The association of enumeration and number comparison capacities with arithmetical competence was examined in a large sample of children from 2nd to 9th grades. It was found that efficiency on numerical capacities predicted separately more than 25% of the variance in the individual differences on a timed arithmetical test, and this occurred for both younger and older learners. These capacities were also significant predictors of individual variations in an untimed curriculum-based math achievement test and on the teacher scores of math performance over developmental time. Based on these findings, these numerical capacities were used for estimating the prevalence and gender ratio of basic numerical deficits and developmental dyscalculia (DD) over the grade range defined above (N = 11,652 children). The extent to which DD affects the population with poor ability on calculation was also examined. For this purpose, the prevalence and gender ratio of arithmetical dysfluency (AD) were estimated in the same cohort. The estimated prevalence of DD was 3.4%, and the male:female ratio was 4:1. However, the prevalence of AD was almost 3 times as high (9.35%), and no gender differences were found (male:female ratio = 1.07:1). Basic numerical deficits affect 4.54% of school-age population and affect more boys than girls (2.4:1). The differences between the corresponding estimates were highly significant (α < .01). Based on these contrastive findings, it is concluded that DD, defined as a defective sense of numerosity, could be a distinctive disorder that affects only a portion of children with AD.

Basic numerical processing has been regularly assessed using numerical nonsymbolic and symbolic comparison tasks. It has been assumed that these tasks index similar underlying processes. However, the evidence concerning the reliability and convergent validity across different versions of these tasks is inconclusive. We explored the reliability and convergent validity between two numerical comparison tasks (nonsymbolic vs. symbolic) in school-aged children. The relations between performance in both tasks and mental arithmetic were described and a developmental trajectories' analysis was also conducted. The influence of verbal and visuospatial working memory processes and age was controlled for in the analyses. Results show significant reliability (p < .001) between Block 1 and 2 for nonsymbolic task (global adjusted RT (adjRT): r = .78, global efficiency measures (EMs): r = .74) and, for symbolic task (adjRT: r = .86, EMs: r = .86). Also, significant convergent validity between tasks (p < .001) for both adjRT (r = .71) and EMs (r = .70) were found after controlling for working memory and age. Finally, it was found the relationship between nonsymbolic and symbolic efficiencies varies across the sample's age range. Overall, these findings suggest both tasks index the same underlying cognitive architecture and are appropriate to explore the Approximate Number System (ANS) characteristics. The evidence supports the central role of ANS in arithmetic efficiency and suggests there are differences across the age range assessed, concerning the extent to which efficiency in nonsymbolic and symbolic tasks reflects ANS acuity.

Learning to read is one of the most important cognitive milestones in the human social environment. One of the most accepted models explaining such process is the Double-Route Cascaded Model. It suggests the existence of two reading strategies: lexical and sublexical. In the Spanish language there are some contradictions about how these strategies are applied for reading. In addition, there are only a few studies dealing with the analysis of shifts between them, achieving a fluent reading process. In this paper we use a reading task including words and pseudowords for characterizing the cost of shifting between reading strategies in children with developmental dyslexia and normal controls. Our results suggest the presence of both strategies in these two experimental groups. In controls, both strategies become more efficient in correspondence to the increased exposition to written material. However, in children with developmental dyslexia only the lexical strategy exhibits such improvement. Their also point to a low cost for shifting between strategies in controls and a much more significant one in children with developmental dyslexia, differentiating subgroups with distinct shifting patterns.El aprendizaje de la lectura constituye uno de los hitos cognitivos más importantes del entorno social humano. Uno de los modelos de lectura más aceptados ha sido el Modelo de Doble Ruta en Cascada que sugiere la existencia de dos estrategias de lectura: lexical y sublexical. En el idioma español existen datos contradictorios acerca de cómo se aplican estas estrategias y no hay estudios que describan cómo se realizan los cambios de una a otra para lograr una lectura fluida. En este trabajo utilizamos una tarea de lectura de palabras y pseudopalabras para caracterizar el costo de cambio de una a otra estrategia en niños buenos lectores y niños con dislexia del desarrollo. Nuestros resultados sugieren la presencia de ambas estrategias en los dos grupos. En los niños buenos lectores ambas estrategias se hacen más eficientes con el grado de exposición a la lectura. Sin embargo, en los niños disléxicos esto solo ocurre en la estrategia lexical. Además, indican que los niños buenos lectores desarrollan un bajo costo en el cambio de estrategia de lectura mientras que un subgrupo de niños disléxicos presenta un costo mayor, conformándose subgrupos con patrones diferentes de afectación selectiva. Palabras clave: estrategias de lectura, cambio, español, niños disléxicos.

Objetivo: Determinar el periodo intergenésico como factor de riesgo para el desarrollo de preeclampsia en gestantes atendidas en una Maternidad de Alto Riesgo entre enero y junio de 2018. Métodos: Se realizó una investigación retrospectiva, transversal, analítica de 160 casos y 161 controles a partir de historias clínicas. Resultados: Las medianas de las edades fueron 28,00 ± 9,00 años para los casos y 38,00 ± 2,00 años para los controles (p=0,000). El antecedente personal más frecuente fue la hipertensión arterial (6,3 %, 10 mujeres). Los antecedentes familiares más relevantes fueron hipertensión arterial (13,8 %, 22) y diabetes (13,1 %, 21). El antecedente obstétrico más frecuente fue la cesárea anterior (67,5 %, 108 gestantes) (Z=6,16; p=0,00). La preeclampsia con criterio de gravedad predominó estadísticamente (93,8 %, 150 pacientes) (Z=15,54 y p=0,00). La eclampsia fue la complicación más frecuentes con 5,6 % (9 gestantes). El 91,3 % (146 pacientes) no presentó ninguna complicación. La mediana del periodo intergenésico fue 60,00 ± 63,75 meses para los casos y 38,00 ± 33,00 para los controles (p=0,11). Fue corto en 41 casos (25,6 %) y 26 controles (16,1 %); adecuado en 33 (20,6 %) casos y 84 (52,2 %) controles y prolongado en 86 casos (53,8 %) y 51 controles (31,7 %) (p=0,00). Tener un periodo intergenésico inadecuado (corto o prolongado) constituyó un factor riesgo 4,26 veces mayor de tener la PE en comparación (OR= 4,26; IC 95 %: 2,59 – 6,98). Conclusiones: Tener un periodo intergenésico inadecuado eleva cuatro veces el riesgo de desarrollar preeclampsia. Palabras clave: Hipertensión, Preeclampsia, Periodo intergenésico.

The purpose of the current study was to qualitatively explore the home mathematical environment across two regions in two different countries (i.e., Cuba and Mexico), replicating a qualitative study previously conducted in Northern Ireland (NI), United Kingdom (UK; Cahoon et al., 2017). Semi-structured interviews with parents/caregivers of children (3-5-year-olds) in both Mexico (n = 13) and Cuba (n = 40) were completed to investigate their views, experiences and attitudes towards the home mathematical environment. Thematic analysis was used to explore themes relevant to the home mathematical environment. Three consistent themes were found in the Mexican and Cuban data: Numeracy Environment Structure, Expectations and Attitudes and Views of Technology. Two unique themes were found in the Mexico data: Interactions Related to Reading or Mathematics, and Child’s Attitudes in Relation to Mathematics. One unique theme was found in the Cuban interviews: Interactions for Learning. Although diverse themes were identified, consistencies were also observed. This suggests that some home numeracy practices may be universal in nature. This research increases understanding of human development in context.