Reduced Brain Activity Seen in Prereaders With Dyslexia Risk

Reduced activity in bilateral occipitotemporal and left temporoparietal regions

WEDNESDAY, Jan. 25 (HealthDay News) -- Prereading children with a family history of developmental dyslexia (DD) show reduced activity in the bilateral occipitotemporal and left temporoparietal brain regions during phonological processing exercises, according to a study published online Jan. 23 in the Proceedings of the National Academy of Sciences.

Nora Maria Raschle, Ph.D., from the Children's Hospital Boston, and colleagues analyzed functional magnetic resonance imaging scans taken in 36 prereading children during phonological processing exercises to identify functional networks. Eighteen children with a familial risk for DD (average age, 66.5 months) were compared with 18 age- and IQ-matched controls.

The researchers found that, based on functional neuroimaging results, there was reduced activation in bilateral occipitotemporal and left temporoparietal brain regions in prereading children with a family-history of DD, compared with those without a family history. In both groups, left occipitotemporal and temporoparietal brain activity was positively associated with prereading skills.

"Our results suggest that differences in neural correlates of phonological processing in individuals with DD are not a result of reading failure, but are present before literacy acquisition starts. Additionally, no hyperactivation in frontal brain regions was observed, suggesting that compensatory mechanisms for reading failure are not yet present," the authors write.

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