Reading skill–fractional anisotropy relationships in visuospatial tracts diverge depending on socioeconomic status

Abstract

Low socioeconomic status (SES) has been repeatedly linked with decreased academic achievement, including lower reading outcomes. Some lower SES children do show skills and scores commensurate with those of their higher SES peers, but whether their abilities stem from the same systems as high SES children or are based on divergent strategies is unknown. We here investigated a potential interactive relationship between SES and real-word reading skill in the white matter in 42 typically developing children. SES was determined based on parental education; reading skill and age were not significantly related to SES. There was a significant neural interaction: Clusters in the bilateral inferior longitudinal fasciculus (ILF), left superior longitudinal fasciculus, and left corticospinal tract demonstrated interactive skill–SES relationships in fractional anisotropy. Follow-up analyses demonstrated that higher SES children showed a positive relationship between fractional anisotropy, reflecting tract coherence, and reading skill in left hemisphere tract clusters, whereas lower SES children showed a positive relationship in the right hemisphere homologues. Broadly, the ILF has been demonstrated to support orthographic skill on the left and more general visuospatial processing on the right, so high reading achievement in lower SES children may rely on supplementary visuospatial processing more than for higher SES readers. This pattern is consistent with previous work reporting low SES children’s environments to include less rich verbal experience, which may lead them to disproportionately draw on visuospatial skills for success. Further, these results indicate that group SES differences may be best described by an adaptive, not a deficit, model.

The relationship between socioeconomic status and white matter microstructure in pre‐reading children: A longitudinal investigation

“…Overall, the findings of a positive association between SES with left and right ILF FA and a negative association with RD are in line with documented SES‐related differences in neural structure and function across development (Hanson et al, ; Jednoróg et al, ; Lawson, Duda, Avants, Wu, & Farah, ; Mackey et al, ; Noble et al, ; Noble et al, ; Raizada & Kishiyama, ). Consistent with the present findings, lower parental SES has been associated with decreased FA in multiple white matter clusters including in the bilateral ILF tract in older children (Gullick et al, ). To our knowledge, no studies to date have directly investigated differences in white matter based on SES in younger kindergarten children.…”

“…Consistent with previous studies that demonstrated modulatory influences of SES on the brain–reading relationship (Brito, Piccolo, & Noble, ; Gullick et al, ; Noble et al, ; Romeo et al, ), ILF FA in kindergarten was associated with better second‐grade reading outcomes in lower‐SES but not higher‐SES children. The longitudinal nature of the current findings is a notable difference from other studies that only examined the SES × brain association with reading concurrently.…”

“…All mothers and 95% of fathers in the current lower‐SES sample had completed high school, whereas the national high school completion rate stands at 83% (Aud et al, ). Nevertheless, the mean SES of the sample is comparable to previous neuroimaging studies of SES in children (e.g., Gullick et al, ; Noble et al, ; Skoe, Krizman, & Kraus, ) and even greater disparities between the two SES groups would be expected were the lower‐SES group less advantaged. Second, because white matter development begins in utero and continues through adolescence, in order to gain a deep, mechanistic understanding of the role of parental SES in a child's brain development and to disentangle hereditary from environmental influences, future work needs to examine these effects in infancy and longitudinally.…”

“…In the later study of older children ages 8–14, higher SES was associated with higher FA in several white matter tracts involved in reading, and SES moderated the association between tract measures and reading ability, such that brain–reading ability links were stronger in lower‐SES children (Gullick et al, ). Interpretation of that study is difficult, however, because the commonly observed relation between SES and reading ability (e.g., Reardon, ) was not observed in this study.…”

A Failure to Communicate: Are University Websites Readable?

“…In a recent study where low socioeconomic status was determined by level of parental higher education, Gullick, Demir-Lira, and Booth (2016) found that low SES children demonstrated a positive relationship in the right hemisphere homologues when performing reading comprehension tasks, indicating that these children engage in more visuospatial processing to replace their lack of verbal processing ability. This is due in part to low SES children experiencing less verbal environments as their brain matures.…”