Brain MRIs may provide an early diagnostic marker for dyslexia

January 23, 2012

Children at risk for dyslexia show differences in brain activity on MRI scans even before they begin learning to read, finds a study at Children's Hospital Boston. Since developmental dyslexia responds to early intervention, diagnosing children at risk before or during kindergarten could head off difficulties and frustration in school, the researchers say. Findings appear this week in the online Early Edition of the Proceedings of the National Academy of Sciences.

Developmental dyslexia (dyslexia that's not caused by ) affects 5 to 17 percent of all children; up to 1 in 2 children with a family history of dyslexia will struggle with reading themselves, experiencing poor spelling and decoding abilities and difficulties with fluent word recognition. Because of problems recognizing and manipulating the underlying sound structures of words (known as phonological processing), children with dyslexia have difficulty mapping oral sounds to written language.

The Children's Hospital Boston researchers, led by Nora Raschle, PhD, of the Laboratories of , performed functional in 36 preschool-age children (average age, 5 1/2) while they performed tasks requiring them to decide whether two words started with the same speech sound. They used an elaborate protocol to get these young children to hold still in the .

During the phonological tasks, children with a family history of dyslexia had reduced metabolic activity in certain (the junctions between the occipital and and the temporal and in the back of the brain) when compared with controls matched for age, IQ and socioeconomic status.

"We already know that older children and adults with dyslexia have dysfunction in the same brain regions," says senior investigator Nadine Gaab, PhD, also of the Laboratories of Cognitive Neuroscience. "What this study tells us is that the brain's ability to process language sounds is deficient even before children have reading instruction."

In both the at-risk and control groups, children with high activation in these brain areas had better pre-reading skills, such as rhyming, knowing letters and letter sounds, knowing when two words start with the same sound, and being able to separate sounds within a word (like saying "cowboy" without the "cow").

The children at risk for dyslexia showed no increase in activation of frontal brain regions, as has been seen in older children and adults with dyslexia. This suggests that these regions become active only when children begin reading instruction, as the brain tries to compensate for other deficits.

Studies have shown that children with dyslexia often have negative experiences in school, being labeled as lazy or unmotivated. Their frustration can lead to aggressive, impulsive and anti-social behaviors and an increased likelihood of dropping out of high school and entering the juvenile justice system.

"We hope that identifying children at risk for dyslexia around preschool or even earlier may help reduce the negative social and psychological consequences these kids often face," says Raschle.

While various neuropsychological interventions are available for dyslexia, the condition generally isn't diagnosed until the child has reached third grade, when they are less effective, Gaab adds.

"Families often know that their child has dyslexia as early as kindergarten, but they can't get interventions at their schools," she says. "If we can show that we can identify these kids early, schools may be encouraged to develop programs."

Gaab and Raschle plan to follow the children over time to see if the brain patterns they observed correlate with a later diagnosis of dyslexia They just received a large NIH grant to extend their study, and are actively enrolling preschool-aged children (for information on enrollment, contact the Gaab lab.

Explore further: Dyslexia independent of IQ

Related Stories

Dyslexia independent of IQ

September 26, 2011
About 5 to 10 percent of American children are diagnosed as dyslexic. Historically, the label has been assigned to kids who are bright, even verbally articulate, but who struggle with reading — in short, whose high IQs ...

Skilled readers rely on their brain's 'visual dictionary' to recognize words

November 14, 2011
Skilled readers can recognize words at lightning fast speed when they read because the word has been placed in a visual dictionary of sorts, say Georgetown University Medical Center (GUMC) neuroscientists. The visual dictionary ...

Linking reading to voice recognition

July 29, 2011
When people recognize voices, part of what helps make voice recognition accurate is noticing how people pronounce words differently. But individuals with dyslexia don't experience this familiar language advantage, say researchers.

Research aimed at helping dyslexic children learn

June 6, 2011
A new MRI-based study of children with dyslexia by a UT Arlington professor could explain why a small percentage of dyslexic children don’t respond to current teaching strategies.

Recommended for you

Researchers crack the smile, describing three types by muscle movement

July 27, 2017
The smile may be the most common and flexible expression, used to reveal some emotions, cover others and manage social interactions that have kept communities secure and organized for millennia.

Even babies can tell who's the boss, UW research says

July 27, 2017
The charismatic colleague, the natural leader, the life of the party - all are personal qualities that adults recognize instinctively. These socially dominant types, according to repeated studies, also tend to accomplish ...

Ketamine for depression encouraging, but questions remain around long-term use

July 27, 2017
A world-first systematic review into the safety of ketamine as a treatment for depression, published in the prestigious Lancet Psychiatry, shows the risks of long-term ketamine treatment remain unclear.

DREAMers at greater risk for mental health distress

July 27, 2017
Immigrants who came to the United States illegally as small children and who meet the requirements of the Development Relief and Education for Alien Minors Act, more commonly known as DREAMers, are at risk for mental health ...

Negativity, be gone—new online tool can retrain your brain

July 27, 2017
Anxiety and depression can have devastating effects on people's lives. In some cases, the mental disorders lead to isolation, poverty and poor physical health, things that often cascade to future generations.

Research aims to shape more precise treatments for depression in women

July 27, 2017
Among women in the United States, depression is at epidemic levels: Approximately 12 million women in the U.S. experience clinical depression each year, and more than 12 percent of women can expect to experience depression ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.