The structure of intelligence in children with specific learning disabilities is different as compared to typically development children

Abstract

Children with specific learning disabilities (SLDs) are characterized by a poor academic achievement despite an average intelligence. They are therefore typically assessed not only with achievement tests, but also with intelligence tests, usually the Wechsler Intelligence Scale for Children (WISC). The assumption of a discrepancy between IQ and achievement in children with SLD has been questioned, however, and the implications of using different measures in batteries of intellectual subtests have not been thoroughly investigated. The present study examined these issues, taking advantage of a large database of scores obtained in the ten core subtests of the WISC-IV by a group of 910 Italian children with a clinical diagnosis of SLD, who were compared with the children considered for national standardization purposes. Our results support the doubts raised concerning the IQ-achievement discrepancy model, showing that relevant discrepancies can emerge even within the WISC profile. The four main WISC-IV indexes were found differently related to intelligence (measured by means of the g-factor) and the g content of many subtests differed in children with SLD vis-à-vis typically-developing children. These results have important implications both theoretical, indicating that the g-factor is weakly identified in children with SLD children, and practical, indicating that the QI obtained with the WISC-IV may not be a good measure of intellectual functioning for children with SLD, which are discussed.  There are differences in the g content of the indexes and many subtests between SLD cases and controls.Intelligence, WISC-IV and SLD 2 The structure of intelligence in children with specific learning disabilities is different as compared to typically development childrenIntelligence is one of the most important and most often assessed constructs in psychology (Gottfredson, 1997a). It has been demonstrated, for instance, that intelligence tests such as the WISC, the WAIS and the Raven progressive matrices are among the psychological tests most commonly used in Europe, taking first, second and fourth places, respectively (Evers et al., 2012). This may be due to the importance of intelligence, which is also confirmed by the fact that intelligence can predict important academic and occupational outcomes, and performance in everyday life (e.g., Deary, Strand, Smith, & Fernandes, 2007;Gottfredson, 1997b;Schmidt & Hunter, 2004).The WISC, and particularly the WISC-IV (Wechsler, 2003), which is the latest version to become available in many countries, is one of most often used psychological tests. The popularity of the WISC-IV is probably due to the fact that it is relatively quick to administer and it measures important cognitive factors of relevance to the assessment of both typical populations and clinical groups (Prifitera, Saklofske, & Weiss, 2008). The WISC-IV, as presented in the test manuals, is structured around four factors, considered among the main basic factors underlying intelligence: i) the verbal comprehension ...

Separating math from anxiety: The role of inhibitory mechanisms

“…First, in agreement with previous studies, we found that children with DD failed in a WM task in which they were asked not only to recall, but also to manipulate and process previously presented information Passolunghi & Siegel, 2001;Schuchardt, et al, 2008;Swanson & Sachse-Lee, 2001;Szűcs, 2016). It is also well known that the general cognitive profile of children with specific learning disorders shows impairment in WM and processing speed indexes (Giofrè & Cornoldi, 2015;Toffalini, et al 2017). Additionally, to better understand the role of WM impairments in DD and MA groups, we compared their performances with the combined group (i.e., MA-DD).…”

Forward and backward digit span difficulties in children with specific learning disorder

“…In fact, the relationship between digit span and GAI is stronger for the backward than for the forward version in TDC, whereas in children with SLD the relationship is generally weaker and does not differ significantly between the backward and forward versions of the task. These findings are in line with the hypothesis that intelligence is organized differently in TDC and SLD children (Giofrè & Cornoldi, 2015). Even if the differences in the correlations among the TDC versus the SLD groups may actually seem not large (.10 and .25 in TDC versus .15 and .10 in SLD), however, this small difference in the correlation pattern may be particularly relevant for explaining the observation that the overall g-content of these tasks at the latent level is reduced in the case of SLD (Giofrè & Cornoldi, 2015).…”

“…The digit span subtest was included in all the latest versions of the WISC battery and in all its various international adaptations. Digit span has often been considered in studies examining STM performance in children with SLD, recording a standardized difference between SLD and TDC groups ranging from .65 to .71 (Giofrè & Cornoldi, 2015;Styck & Watkins, 2014), resembling the figure reported by Melby-Lervag and coauthors (2012) for all STM measures. But research conducted to date has not systematically investigated the potential differences between the two classical versions (forward and backward) of the digit span task, both of which are included in the WISC battery.…”

“…Instead, children with SLD have intelligence within the normal range, but specific impairments in some processing measures (American Psychiatric Association, 2013), including aspects of WM (Swanson, 1994). In fact has been suggested that the difficulty experienced by children with SLD in WM tasks reflects a specific problem unrelated to their general intellectual level and executive functioning (Giofrè & Cornoldi, 2015). It may therefore be that children with SLD have impairments in basic STM functioning that relate to their phonological difficulties but not in the executive control of phonological information.…”

Strengths and Weaknesses in the Intellectual Profile of Different Subtypes of Specific Learning Disorder

“…However, the specific VCI-PRI pattern in spelling disorder differed from that in reading disorder, as in the former case the two indexes were not differentiated, while in reading disorder there was a superiority of PRI over VCI. Note that reading and spelling disorder were marked by a GAI in the normal range but significantly higher than the normative sample; as the GAI index is known to be more related to g-factor than the CPI (Giofrè & Cornoldi, 2015). This may suggest that the core intellectual functions could be even above average in certain categories of children who receive a diagnosis of SLD.…”