Sensitive periods for white matter plasticity and reading intervention

Abstract

As a child matures, some brain circuits stabilize while others remain plastic. However, the literature on maturational changes in the brain's capacity for experience-dependent plasticity is primarily based on experiments in animals that mature over dramatically different time-scales than humans. Moreover, while principles of plasticity for sensory and motor systems might be conserved across species, the myriad of late-developing and uniquely human cognitive functions such as literacy cannot be studied with animal models. Here we use an intensive reading intervention program, in combination with longitudinal diffusion MRI measurements in school-aged children with dyslexia, to investigate the sensitive period for white matter plasticity and literacy learning. We find that the intervention induces large-scale changes in white matter diffusion properties, and improvements in reading scores, but that the magnitude and timecourse of plasticity does not depend on the subject's age. Thus, we conclude that, for the intensive, oneon-one reading intervention program employed here, if a sensitive period exists, it does not end before middle school.

Multimodal principal component analysis to identify major features of white matter structure and links to reading

“…White matter abnormalities have been observed in children with reading difficulties, most often in left temporo-parietal white matter [11][12][13][14] as language and reading networks are typically left lateralized [11,15,16]. Finally, changes in DTI measures are observed in reading-related white matter following reading interventions [17][18][19].…”

Do Younger Children Benefit More From Cognitive and Academic Interventions? How Training Studies Can Provide Insights Into Developmental Changes in Plasticity

“…So far, a few meta-analyses of EF training studies in children and adolescents have found no age effects (Sala & Gobet, 2020;Scionti et al, 2019), raising the possibility that there may not be a clear overall younger age benefit as previously suggested. In the academic domain, complex reading interventions may show plasticity over wider age ranges than previously thought (Yeatman & Huber, 2019). On the other hand, in studies that individually targeted skills like phonological awareness, there is some evidence from meta-analyses for a benefit to intervening at early grade levels (Bus & Van Ijzendoorn, 1999;Ehri et al, 2001), while interventions for more complex abilities, like reading comprehension, become more important later on (Suggate, 2010).…”

“…One notable study directly examined the impact of an intensive reading intervention program on white matter plasticity changes in 7-to 13-year-olds with dyslexia or parent-reported reading difficulties (Yeatman & Huber, 2019). The intervention consisted of 8 weeks of the Seeing Stars program, which focuses on training orthographic and phonological processing skills.…”

Sex Differences in White Matter Diffusivity in Children with Developmental Dyslexia

“…Limitations of this study included its sample of only third and fourth graders (M = 8.82). Although this did not allow for the examination of sex differences in white matter development over time in these children, it is important to note that this age represents a point of critical development, particularly in terms of language and reading [ 85 , 86 ]. It is still important to note that the differences observed in this age group may change over time with continued brain and reading skill development, which might alter sex differences.…”