Left lateralized white matter microstructure accounts for individual differences in reading ability and disability

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Science

Background:

• Individual differences in reading skill are influenced by white matter microstructure.
• Previous studies primarily focused on typically developing children.
• The role of white matter in reading disability (RD) requires further investigation.

Purpose of the Study:

• To investigate the association between white matter microstructure and reading skill variation in children.
• To examine if white matter differences extend across the continuum from average reading to reading disability.
• To explore the relationship between working memory, frontal white matter, and reading-associated posterior white matter.

Main Methods:

• Diffusion tensor imaging (DTI) was employed to assess white matter microstructure.
• Fractional anisotropy (FA) values were correlated with standardized reading scores.
• The study included children with average reading skills and those with reading disability (RD).

Main Results:

• A strong correlation was found between left temporo-parietal white matter FA values and reading scores in typically developing children.
• These FA values also differentiated children with average reading skills from those with RD, suggesting a continuum.
• Working memory showed correlations with frontal white matter, independent of posterior reading-related regions, forming a correlational double dissociation.

Conclusions:

• White matter microstructure in posterior regions is crucial for reading skill across a continuum of performance.
• Working memory and reading skill rely on distinct white matter networks, demonstrating domain specificity.
• DTI findings support a neurobiological basis for reading differences, extending from typical variation to reading disability.