dyslexia

Dyslexia: the Writing is on the Wall—From Birth

dyslexic from birth smallMost of us with dyslexia were diagnosed after several failure-filled, white-knuckled, angst-ridden years in school, or even as late as adulthood. Diagnosis at any age is a good thing: it allows us to finally understand our experience and educate ourselves on coping strategies. But it looks as if future generations may not have to suffer the extensive stress, crippling academic lag, and self-esteem issues we did. Boston Children’s Hospital Laboratory of Cognitive Science is out to change things.

Nadine Gaab, PhD, and lab members Nicolas Langer, PhD, and Barbara Peysakhovich have found that the signs of dyslexia are present as early as infancy. In 2012, the Gaab Lab showed that pre-readers with a family history of dyslexia (average age, 5½) have differences in the left hemisphere of their brains on magnetic resonance image (MRI).

“The first day they step in a kindergarten classroom, they are already less well equipped to learn to read,” Gaab says.

Some researchers postulate that kids had that difference because of dyslexic parents, and poor learning environments at home. But what if the brain difference was caused by nature, not nurture? To get to the bottom of that question, Gaab and her team performed MRI scans on 14 infants from dyslexic family histories, and 18 same-age infants without dyslexic family history. All the infants were only 18 months old.

The MRI scan utilized an advanced technique called diffusion tensor imaging (DTI). DTI measures the flow of water molecules along the brain’s fiber tracts, and gives a good indication of fiber structure, orientation, and its impact on how well information is flowing in the brain.

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The arcuate fasciculus in a child with a family history of dyslexia (L) versus no family history (R), as seen on DTI (attribution footnoted)

The findings, published in the journal Cerebral Cortex, discovered alterations in a particular structure called the arcuate fasciculus, a bundle of fibers that connect the posterior cortex, which is involved in mapping sounds and word/letter recognition, with the frontal cortex, which integrates and comprehends this information.

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Detailed segmentation of the images revealed that fibers in certain areas of the arcuate fasciculus, shown above as red bands, were consistently less organized. (Attribution footnoted)

Historically, people who have suffered damage to the arcuate fasciculus have problems with expressive and receptive language and with phonological processing — the ability to manipulate and understand the sounds of a language, a critical part of learning to read. In infants with familial dyslexia, inherited genes may interfere with the development of the arcuate fasciculus before birth, says Gaab, impairing its structural integrity.

“The street could be full of potholes, or it could be the street is narrow or has a really crappy surface, or there might be a lot of intersections where you have to stop,” she says, describing how an individual’s processing could be impacted by these structural changes.

“We hope this study will help show that kids should get interventions before kindergarten,” says Gaab. “We’re not saying you should scan every kindergartener, but if you have a strong family history, you could potentially have a five-minute DTI scan to see if you are at risk.”

As I have often discussed in this venue, the earlier the intervention, the better. Intervention from toddlerhood may have never seemed possible in the past, but these important findings offer parents the opportunity to get their kids off to the best possible educational start in life. It truly is a good time to be alive.

Sources and Image Sources:
http://m.cercor.oxfordjournals.org/content/early/2015/12/04/cercor.bhv281
http://www.tandfonline.com/doi/abs/10.1207%2FSLDRP1501_6
http://vector.childrenshospital.org/2015/12/for-dyslexia-writing-is-often-on-the-wall-from-birth/