The prevalence of developmental dyscalculia in Brazilian public school system

Abstract

The goal of the study was to assess public school children at the end of the first stage of elementary school. We used a protocol applied concurrently with a writing test in the form of an unexpected activity in 28 public schools; 2,893 children assessed, 687 exhibited performance below 58 points, 184 were excluded due to change of address or lack of consent; 503 children subjected to a test of intellectual capacity and reading assessment and 71 considered intellectually disabled were excluded. 226 (7.8%) children, who could read, write, and had normal intellectual level, met the criteria of developmental dyscalculia (DD), 98 female and 128 male. The most influential factors in the prevalence were socioeconomic levels of the schools neighborhood, education level of parents, and being male, as demonstrated by the odds ratio and multiple logistic regression analysis. Further studies should be done so that educational policies are taken.

Persistent Effects of Musical Training on Mathematical Skills of Children With Developmental Dyscalculia

“…For this reason, prevalence rates may vary in different countries. For instance, in Brazil, Bastos et al (2016) found a slightly higher prevalence (7.8% from a cohort of 2.893 children) compared to previously quoted studies. Nevertheless, Fortes et al (2016) found 6% of prevalence in a cohort of 1.618 children from four different Brazilian states.…”

“…Besides, an objective criterion for the DD diagnosis was assured by the cut-off of 1.5 SD below the mean age in the Zareki-R (Rotzer et al, 2009). In the present study, using the two-phase procedure, i.e., screening, and neuropsychological assessment (Shalev et al, 2005), the prevalence of DD was 5.4%, comprising more boys (60%) than girls (Bastos et al, 2016).…”

“…Both Brazilian authors adopted cubes and vocabulary subtests of the Wechsler Intelligence Scale for Children (WISC-III) to assess the intellectual level. However, various mathematical screening protocols were used, for instance, Bastos et al (2016) applied Grafman and Boller's modified protocol, while Fortes et al (2016) used the schooling achievement test (Stein, 1994). These divergences reveal the need to control the instruments selected, which should be standardized and not restricted to screening measures (Butterworth, 2005).…”

Hand preference and Mathematical Learning Difficulties: New data from Greece, the United Kingdom, and Germany and two meta-analyses of the literature

“…Worldwide MLD has been estimated to affect between 3% to 9.9% of schoolage children by studies conducted in various countries, such as the United States of America (5%-8%; Geary, 2004), Greece (6.3%; , Serbia (9.9%; Jovanović et al, 2013), Germany (6.6%; Hein et al, 2000), Belgium (3% -8%; Desoete, Roeyers, & De Clercq, 2004), Brazil (7.8%; Bastos, Cecato, Martins, Grecca, & Pierini, 2016), Slovakia (6.4%; Kosc, 1974), Israel (6.5%;Gross-Tsur, Manor, & Shalev, 1996), and India (5.98%, 5.54%; Ramaa & Gowramma, 2002). A recent study showed that females are 32% less likely than males to present MLD (White, Ruther, & Kahn, 2016) and the male to female ratio has been calculated to be 4:1 by another study by Reigosa-Crespo et al (2012).…”

Numeracy musical training for school children with low achievement in mathematics

“…Devine, Soltész, Nobes, Goswami, and Szűcs (2013), based on 17 epidemiological studies indicated that prevalence of DD is around 5-6%, their survey carried out with 1004 British children showed an equal presence of the disorder in boys and girls, depending on the inclusion criteria (Devine, et al, 2013). The study by Bastos, Cecato, and Martins (2016) analysed the prevalence of DD in Brazilian primary school children (n = 226) and concluded that 7.8% met disorder criteria. Results analysis showed a higher prevalence among male children from schools in more vulnerable neighbourhoods, from parents with little schooling.…”