They conducted brain imaging tests before and after the remediation period on children 8 to 10 years old, including 47 with weak word decoding skills and 25 who had had good reading scores.
The researchers used a test called diffusion tensor imaging, or DTI, which measures the flow of water through the white matter tracts of the brain. This provides a snapshot of the brain's structure and can be used to compare changes over time.
They found that those with reading problems had decreased microstructural organization of the white matter in a region of the left frontal lobe.
Most of the poor readers (35 of the 47) received remedial training for six months, and the others, including 12 poor readers, had no reading intervention. At the end of the training period, when the children were rescanned, the scientists found that "the instruction resulted in a change in white matter in the very same region that showed deficiencies in white matter before the intervention," Just said.
The changes on the brain scan correlated with improvements on some of the reading measures, he added. Scientists have never before shown that the brain's white matter grows in response to intense but relatively brief remedial training, the team said.
No changes were detected in the white matter in those poor readers who had no remedial intervention. "This suggests that it is not a matter of development but of the intervention itself," Just said.
"I think as the children use these circuits over and over again, the specialized glial cells [called oligodendrocytes] that construct the white matter are building up more myelin [the protective insulation of the white matter fibers] along the axons being fired," Just explained. This makes the neural signal travel 10 times faster and delivers a more precise signal, he said.
The finding may offer hope for other neurological problems. "There are many wo
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