Small or absent Visual Word Form Area is a trait of dyslexia

Conducted in collaboration with LBLP, this study from Stanford University investigated how the brains of dyslexic learners adapt to reading interventions over time. The study focuses on whether differences in the visual word form area (VWFA)—a crucial region in the left ventral occipitotemporal cortex (VOTC) responsible for recognizing written words—are a stable trait of dyslexia or if they can change as struggling readers improve with targeted interventions.

The study included 44 children with dyslexia, who completed 160 hours of the Seeing Stars program (delivered remotely during the summer for eight weeks due to the COVID-19 pandemic), and 46 control children, 21 of whom had dyslexia and 25 without. These participants underwent functional magnetic resonance imaging (fMRI) and behavioral assessments at five different points throughout the year. 

The analysis compared the brain regions in two different ways: first, at the beginning of the study, to examine differences in their presence, size, and function among participants with varying reading abilities, and second, over time, to explore how these regions changed as reading skills improved.

The findings revealed that dyslexic readers show significant differences in VWFA presence, size, and tuning properties compared to typical readers. The study confirms that while the intervention led to statistically significant improvements in reading skills and increased VWFA size, dyslexic readers still exhibit smaller VWFAs than their typical peers. This suggests that abnormalities in the VWFA may be a lasting trait of dyslexia. Perhaps with sufficient intervention that closes the reading skill gap, dyslexic readers are expected to have smaller VWFAs. The research highlights which aspects of brain function can change through intervention and which remain stable, offering valuable insights into the neurological basis of dyslexia.

b, Proportion of participants with usable data who had a VWFA or FFA of any size present at baseline in typical (light purple) and dyslexic (purple) readers for each ROI. 

c, Log transformed size (in number of vertices) at baseline in typical and dyslexic readers for each ROI.