Structural abnormalities in the dyslexic brain: a meta-analysis of voxel-based morphometry studies

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• Developmental dyslexia is a common neurodevelopmental disorder affecting reading acquisition.
• Previous research has identified both structural and functional brain differences in individuals with dyslexia.
• Understanding these brain abnormalities is crucial for developing effective interventions.

Purpose of the Study:

• To objectively quantify gray matter abnormalities in developmental dyslexia using a coordinate-based meta-analysis.
• To integrate findings from Voxel-Based Morphometry (VBM) studies on dyslexia.
• To explore the relationship between structural and functional brain abnormalities in dyslexia.

Main Methods:

• Coordinate-based meta-analysis of nine Voxel-Based Morphometry (VBM) studies.
• Identification of consistently reported gray matter volume reductions in dyslexic readers.
• Comparison of structural findings with previous meta-analyses of functional brain abnormalities.

Main Results:

• Consistent gray matter volume reduction was observed in the right superior temporal gyrus and left superior temporal sulcus of dyslexic readers.
• Convergence between gray matter reduction and reading-related underactivation was found in the left superior temporal sulcus.
• Evidence suggests pre-reading onset structural and functional abnormalities in temporal and occipito-temporal regions.

Conclusions:

• Gray matter deficits in specific temporal lobe regions are a key neuroanatomical feature of developmental dyslexia.
• The findings highlight the interplay between structural and functional brain alterations in dyslexia.
• Abnormalities in these brain regions may precede the onset of reading difficulties.