Dyslexic girls have different brain anatomy from dyslexic boys

The study found less gray matter volume in parts of male brains used to process language. It found less gray matter volume in parts of females brains used in sensory and motor processing.

Neuroscientists at Georgetown University Medical Center found significant differences in brain anatomy when comparing males and females with dyslexia to non-dyslexics. Because dyslexia is two to three times more prevalent in males, females have been overlooked, according to senior author Guinevere Eden. This is the first study that directly compares brain anatomy of females with and without dyslexia, according to its authors. Results of the study were announced in early May 2013 and published online in the journal Brain Structure and Function.

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Dyslexia is a language processing disorder can hinder reading, writing, spelling, and sometimes even speaking. Photo credit: MaPaSa/Shutterstock

The study used MRIs – magnetic resonance imaging, which can help visualize internal structures of the body in detail – to investigate dyslexia in both males and female children and adults. It compared the brain structure of men, women, boys and girls with dyslexia to those without. In males, the new study showed, less gray matter volume is found in dyslexics in areas of the brain used to process language. This finding is consistent with previous work on dyslexic males. In the females, the new study showed, less gray matter volume is found in dyslexics in areas involved in sensory and motor processing.

Previous work outside of dyslexia demonstrates that male and female brains are different in general, adds the study’s lead author, Tanya Evans, PhD. She said:

There is sex-specific variance in brain anatomy and females tend to use both hemispheres for language tasks, while males just the left.

It is also known that sex hormones are related to brain anatomy and that female sex hormones such as estrogen can be protective after brain injury, suggesting another avenue that might lead to the sex-specific findings reported in this study.

Bottom line: An MRI study by neuroscientists at Georgetown University Medical Center found significant differences in brain anatomy when comparing males and females dyslexia to non-dyslexics.

Read more about the study

Eleanor Imster

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