Age-related changes in reading systems of dyslexic children.

OBJECTIVE

To examine age-related changes in the neural systems for reading in nonimpaired and dyslexic children and adolescents.

METHODS

Functional magnetic resonance imaging was used to study age-related changes in the neural systems for reading in a cross-sectional sample of 232 right-handed children 7 to 18 years of age (113 dyslexic readers and 119 nonimpaired readers) as they read pseudowords.

RESULTS

In nonimpaired readers, systems in the left anterior lateral occipitotemporal area developed with age, whereas systems in the right superior and middle frontal regions decreased. In contrast, in dyslexic readers, systems in the left posterior medial occipitotemporal regions developed with age. Older nonimpaired readers were left lateralized in the anterior lateral occipitotemporal area; there was no difference in asymmetry between younger and older dyslexic readers.

INTERPRETATION

These findings offer a possible neurobiological explanation for the differences in reading acquisition between dyslexic and nonimpaired readers and provide further evidence of the critical role of the left occipitotemporal region in the development of reading.