Researchers have studied how the gray matter of children's brains relates with reading fluency deficits and found that Intelligence Quotient (IQ) plays no role, unlike socioeconomic status.
Knowing that learning to read is one of the main goals of early childhood education, it may be surprising to discover that, in the 38 countries of the OECD - Organization for Economic Co-operation and Development, 20% of children do not attain the baseline level of reading proficiency (OECD 2016). One of the reasons for this fact is that reading is a complex ability that simultaneously requires several neurocognitive systems.
Researchers Marta Martins, Ana Mafalda Reis, São Luís Castro and Christian Gaser, from the Faculty of Psychology and Educational Sciences of the University of Porto, Unilabs Boavista, and Jena University Hospital (Germany), joined efforts to study the brain basis of reading fluency, which remains poorly explored to date. To better understand reading disability in children, the researchers focused on two important variables: IQ and socioeconomic status (SES).
Some previous behavioral studies associated low IQ with persistent reading difficulty (Ingesson, 2005; Swanson, 2012), converging on the view that the neural systems involved in reading could differ in readers with difficulties depending on IQ. With regard to socioeconomic status, several studies have linked the SES to the variation of gray matter volume, which may reflect different home literacy environments with an impact on language and literacy development (e.g. Mol and Bus, 2011; Pace et al., 2017).
In the paper “Gray matter correlates of reading fluency deficits: SES matters, IQ does not”, published in August 2021 in the journal Brain Structure and Function, the authors explain that they used a voxel-based morphometric (VBM) approach in the study in which 54 European Portuguese students participated (31 girls and 23 boys, with an average age of 8 years). The goal was to compare 18 fluent readers with 18 dysfluent readers with normal IQ and 18 dysfluent readers with low IQ and determine whether IQ and SES modulate the brain–behavior relationship in dysfluent readers.
Regarding IQ, the results showed that dysfluent readers of normal and low IQ did not differ in core reading regions and that both subgroups of dysfluent readers had less gray matter volume than fluent readers in the occipito-temporal, parieto-temporal and fusiform areas.
Examination of gray matter volume in subgroups of dysfluent readers differing only in socioeconomic status, showed that higher-SES dysfluent readers had larger gray matter volume in the right angular gyrus than their lower-SES peers and the volume of this area correlated positively with lexico-semantic fluency.
According to São Luís Castro, a researcher supported by the BIAL Foundation, “the two findings resulting from this study add to current evidence of the modulatory effect of SES on the brain-behavior relationship and contribute to an in-depth knowledge of the neurocognitive profile of dysfluent readers which may help envision better strategies to enhance literacy in all children”.
Learn more about the project “The impact of music training on reading and mathematical abilities of normal and reading disabled children: A behavioral and neuroimaging longitudinal study” here.
