Brain Disorder: Dyslexia

Assessing connections in the brain’s reading network

by Jennifer Michalowski |

When we read, information zips between language processing centers in different parts of the brain, traveling along neural highways in the white matter. This coordinated activity allows us to decipher words and comprehend their meaning. Many neuroscientists suspect that variations in white matter may underlie differences in reading ability, and hope that by determining which white matter tracts are involved, they will be able to guide the development of more effective interventions for children who struggle with reading skills.

In a January 14, 2022, online publication in the journal NeuroImage, scientists at MIT’s McGovern Institute report on the largest brain imaging study to date to evaluate the relationship between white matter structure and reading ability. Their findings suggest that if white matter deficiencies are a significant cause of reading disability, new strategies will be needed to pin them down.

White matter is composed of bundles of insulated nerve fibers. It can be thought of as the internet of the brain, says senior author John Gabrieli, the Grover Hermann Professor of Health Sciences and Technology at MIT. “It’s the connectivity: the way that the brain communicates at some distance to orchestrate higher-level thoughts, and abilities like reading,” explains Gabrieli, who is also a professor of brain and cognitive sciences and an investigator at the McGovern Institute.

The left inferior cerebellar peduncle, a white matter tract that connects the cerebellum to the brainstem and spinal cord. Image: Steven Meisler

Long-distance connections

To visualize white matter and study its structure, neuroscientists use an imaging technique called diffusion-weighted imaging (DWI). Images are collected in an MRI scanner by tracking the movements of water molecules in the brain. A key measure used to interpret these images is fractional anisotropy (FA), which varies with many physical features of nerve fibers, such as their density, diameter, and degree of insulation. Although FA does not measure any of these properties directly, it is considered an indicator of structural integrity within white matter tracts.

Several studies have found the FA of one or more white matter tracts to be lower in children with low reading scores or dyslexia than in children with stronger reading abilities. But those studies are small—usually involving only a few dozen children—and their findings are inconsistent. So it has been difficult to attribute reading problems to poor connections between specific parts of the brain.

Hoping to glean more conclusive results, Gabrieli and Steven Meisler, a graduate student in the Harvard Program in Speech and Hearing Bioscience and Technology who is completing his doctoral work in the Gabrieli lab, turned to a large collection of high-quality brain images available through the Child Mind Institute’s Healthy Brain Network. Using DWI images collected from 686 children and state-of-the-art methods of analysis, they assessed the FA of 20 white matter tracts that are thought to be important for reading.

The children represented in the dataset had diverse reading abilities, but surprisingly, when they compared children with and without reading disability, Meisler and Gabrieli found no significant differences in the FA of any of the 20 tracts. Nor did they find any correlation between white matter FA and children’s overall reading scores.

More detailed analysis did link reading ability to the FA of two particular white matter tracts. The researchers only detected the correlation when they narrowed their analysis to children older than eight, who are usually reading to learn, rather than learning to read. Within this group, they found two white matter tracts whose FA was lower in children who struggled with a specific reading skill: reading “pseudowords.” The ability to read nonsense words is used to assess knowledge of the relationship between letters and sounds, since real words can be recognized instead through experience and memory.

The right superior longitudinal fasciculus, a white matter tract that connects frontal brain regions to parietal areas. The research team found that fractional anisotropy (FA) of the right superior longitudinal fasciculus and the left inferior cerebellar peduncles (shown above) correlated positively with pseudoword reading ability among children ages 9 and older. Image: Steven Meisler

The first of these tracts connects language processing centers in the frontal and parietal brain regions. The other contains fibers that connect that the brainstem with the cerebellum, and may help control the eye movements needed to see and track words. The FA differences that Meisler and Gabrieli linked to reading scores were small, and it’s not yet clear what they mean. Since less cohesive structure in these two tracts was linked to lower pseudoword-reading scores only in older children, it may be a consequence of living with a reading disability rather than a cause, Meisler says.

The findings don’t rule out a role for white matter structure in reading disability, but they do suggest that researchers will need a different approach to find relevant features. “Our results suggest that FA does not relate to reading abilities as much as previously thought,” Meisler says. In future studies, he says, researchers will likely need to take advantage of more advanced methods of image analysis to assess features that more directly reflect white matter’s ability to serve as a conduit of information.

International Dyslexia Association recognizes John Gabrieli with highest honor

by Julie Pryor |

Cognitive neuroscientist John Gabrieli has been named the 2021 winner of the Samuel Torrey Orton Award, the International Dyslexia Association’s highest honor. The award recognizes achievements of leading researchers and practitioners in the dyslexia field, as well as those of individuals with dyslexia who exhibit leadership and serve as role models in their communities.

“I am grateful to the International Dyslexia Association for this recognition,” said Gabrieli, who is the Grover Hermann Professor of Health Sciences and Technology, a professor of brain and cognitive sciences, and a member of MIT’s McGovern Institute for Brain Research. “The association has been such an advocate for individuals and their families who struggle with dyslexia, and has also been such a champion for the relevant science. I am humbled to join the company of previous recipients of this award who have done so much to help us understand dyslexia and how individuals with dyslexia can be supported to flourish in their growth and development.”

Gabrieli, who is also the director of MIT’s Athinoula A. Martinos Imaging Center, uses neuroimaging and behavioral tests to understand how the human brain powers learning, thinking, and feeling.  For the last two decades, Gabrieli has sought to unravel the neuroscience behind learning and reading disabilities and, ultimately, convert that understanding into new and better education interventions—a sort of translational medicine for the classroom.

“We want to get every kid to be an adequate reader by the end of the third grade,” Gabrieli says. “That’s the ultimate goal: to help all children become learners.”

In March of 2018, Gabrieli and the MIT Integrated Learning Initiative—MITili, which he also directs—announced a $30 million-dollar grant from the Chan Zuckerberg Initiative for a collaboration between MIT, the Harvard Graduate School of Education, and Florida State University. This partnership, called “Reach Every Reader” aims to make significant progress on the crisis in early literacy – including tools to identify children at risk for dyslexia and other learning disabilities before they even learn to read.

“John is especially deserving of this award,” says Hugh Catts, Gabrieli’s colleague at Reach Every Reader. Catts is a professor and director of the School of Communications Science and Disorders at Florida State University. “His work has been seminal to our understanding of the neural basis of learning and learning difficulties such as dyslexia. He has been a strong advocate for individuals with dyslexia and a mentor to leading experts in the field,” says Catts, who is also received the Orton Award in 2008.

“It’s a richly deserved honor,”says Sanjay Sarma, the Fred Fort Flowers (1941) and Daniel Fort Flowers (1941) Professor of Mechanical Engineering at MIT. “John’s research is a cornerstone of MIT’s efforts to make education more equitable and accessible for all. His contributions to learning science inform so much of what we do, and his advocacy continues to raise public awareness of dyslexia and helps us better reach the dyslexic community through literacy initiatives such as Reach Every Reader. We’re so pleased that his work has been recognized with the Samuel Torrey Orton Award,” says Sarma, who is also Vice President for Open Learning at MIT.

Gabrieli will deliver the Samuel Torrey Orton and Joan Lyday Orton Memorial Lecture this fall in North Carolina as part of the 2021 International Dyslexia Association’s Annual Reading, Literacy and Learning Conference.

 

 

Can fMRI reveal insights into addiction and treatments?

by Sabbi Lall |

Many debilitating conditions like depression and addiction have biological signatures hidden in the brain well before symptoms appear.  What if brain scans could be used to detect these hidden signatures and determine the most optimal treatment for each individual? McGovern Investigator John Gabrieli is interested in this question and wrote about the use of imaging technologies as a predictive tool for brain disorders in a recent issue of Scientific American.

page from Scientific American article
McGovern Investigator John Gabrieli pens a story for Scientific American about the potential for brain imaging to predict the onset of mental illness.

“Brain scans show promise in predicting who will benefit from a given therapy,” says Gabrieli, who is also the Grover Hermann Professor in Brain and Cognitive Sciences at MIT. “Differences in neural activity may one day tell clinicians which depression treatment will be most effective for an individual or which abstinent alcoholics will relapse.”

Gabrieli cites research which has shown that half of patients treated for alcohol abuse go back to drinking within a year of treatment, and similar reversion rates occur for stimulants such as cocaine. Failed treatments may be a source of further anxiety and stress, Gabrieli notes, so any information we can glean from the brain to pinpoint treatments or doses that would help would be highly informative.

Current treatments rely on little scientific evidence to support the length of time needed in a rehabilitation facility, he says, but “a number suggest that brain measures might foresee who will succeed in abstaining after treatment has ended.”

Further data is needed to support this idea, but Gabrieli’s Scientific American piece makes the case that the use of such a technology may be promising for a range of addiction treatments including abuse of alcohol, nicotine, and illicit drugs.

Gabrieli also believes brain imaging has the potential to reshape education. For example, educational interventions targeting dyslexia might be more effective if personalized to specific differences in the brain that point to the source of the learning gap.

But for the prediction sciences to move forward in mental health and education, he concludes, the research community must design further rigorous studies to examine these important questions.

Bridging the gap between research and the classroom

by Stefanie Koperniak |

In a moment more reminiscent of a Comic-Con event than a typical MIT symposium, Shawn Robinson, senior research associate at the University of Wisconsin at Madison, helped kick off the first-ever MIT Science of Reading event dressed in full superhero attire as Doctor Dyslexia Dude — the star of a graphic novel series he co-created to engage and encourage young readers, rooted in his own experiences as a student with dyslexia.

The event, co-sponsored by the MIT Integrated Learning Initiative (MITili) and the McGovern Institute for Brain Research at MIT, took place earlier this month and brought together researchers, educators, administrators, parents, and students to explore how scientific research can better inform educational practices and policies — equipping teachers with scientifically-based strategies that may lead to better outcomes for students.

Professor John Gabrieli, MITili director, explained the great need to focus the collective efforts of educators and researchers on literacy.

“Reading is critical to all learning and all areas of knowledge. It is the first great educational experience for all children, and can shape a child’s first sense of self,” he said. “If reading is a challenge or a burden, it affects children’s social and emotional core.”

A great divide

Reading is also a particularly important area to address because so many American students struggle with this fundamental skill. More than six out of every 10 fourth graders in the United States are not proficient readers, and changes in reading scores for fourth and eighth graders have increased only slightly since 1992, according to the National Assessment of Education Progress.

Gabrieli explained that, just as with biomedical research, where there can be a “valley of death” between basic research and clinical application, the same seems to apply to education. Although there is substantial current research aiming to better understand why students might have difficulty reading in the ways they are currently taught, the research often does not necessarily shape the practices of teachers — or how the teachers themselves are trained to teach.

This divide between the research and practical applications in the classroom might stem from a variety of factors. One issue might be the inaccessibility of research publications that are available for free to all — as well as the general need for scientific findings to be communicated in a clear, accessible, engaging way that can lead to actual implementation. Another challenge is the stark difference in pacing between scientific research and classroom teaching. While research can take years to complete and publish, teachers have classrooms full of students — all with different strengths and challenges — who urgently need to learn in real time.

Natalie Wexler, author of “The Knowledge Gap,” described some of the obstacles to getting the findings of cognitive science integrated into the classroom as matters of “head, heart, and habit.” Teacher education programs tend to focus more on some of the outdated psychological models, like Piaget’s theory of cognitive development, and less on recent cognitive science research. Teachers also have to face the emotional realities of working with their students, and might be concerned that a new approach would cause students to feel bored or frustrated. In terms of habit, some new, evidence-based approaches may be, in a practical sense, difficult for teachers to incorporate into the classroom.

“Teaching is an incredibly complex activity,” noted Wexler.

From labs to classrooms

Throughout the day, speakers and panelists highlighted some key insights gained from literacy research, along with some of the implications these might have on education.

Mark Seidenberg, professor of psychology at the University of Wisconsin at Madison and author of “Language at the Speed of Sight,” discussed studies indicating the strong connection between spoken and printed language.

“Reading depends on speech,” said Seidenberg. “Writing systems are codes for expressing spoken language … Spoken language deficits have an enormous impact on children’s reading.”

The integration of speech and reading in the brain increases with reading skill. For skilled readers, the patterns of brain activity (measured using functional magnetic resonance imaging) while comprehending spoken and written language are very similar. Becoming literate affects the neural representation of speech, and knowledge of speech affects the representation of print — thus the two become deeply intertwined.

In addition, researchers have found that the language of books, even for young children, include words and expressions that are rarely encountered in speech to children. Therefore, reading aloud to children exposes them to a broader range of linguistic expressions — including more complex ones that are usually only taught much later. Thus reading to children can be especially important, as research indicates that better knowledge of spoken language facilitates learning to read.

Although behavior and performance on tests are often used as indicators of how well a student can read, neuroscience data can now provide additional information. Neuroimaging of children and young adults identifies brain regions that are critical for integrating speech and print, and can spot differences in the brain activity of a child who might be especially at-risk for reading difficulties. Brain imaging can also show how readers’ brains respond to certain reading and comprehension tasks, and how they adapt to different circumstances and challenges.

“Brain measures can be more sensitive than behavioral measures in identifying true risk,” said Ola Ozernov-Palchik, a postdoc at the McGovern Institute.

Ozernov-Palchik hopes to apply what her team is learning in their current studies to predict reading outcomes for other children, as well as continue to investigate individual differences in dyslexia and dyslexia-risk using behavior and neuroimaging methods.

Identifying certain differences early on can be tremendously helpful in providing much-needed early interventions and tailored solutions. Many speakers noted the problem with the current “wait-to-fail” model of noticing that a child has a difficult time reading in second or third grade, and then intervening. Research suggests that earlier intervention could help the child succeed much more than later intervention.

Speakers and panelists spoke about current efforts, including Reach Every Reader (a collaboration between MITili, the Harvard Graduate School of Education, and the Florida Center for Reading Research), that seek to provide support to students by bringing together education practitioners and scientists.

“We have a lot of information, but we have the challenge of how to enact it in the real world,” said Gabrieli, noting that he is optimistic about the potential for the additional conversations and collaborations that might grow out of the discussions of the Science of Reading event. “We know a lot of things can be better and will require partnerships, but there is a path forward.”

John Gabrieli

Images of Mind

John Gabrieli’s goal is to understand the organization of memory, thought, and emotion in the human brain, and to use that understanding to help people live happier, more productive lives. By combining brain imaging with behavioral tests, he studies the neural basis of these abilities in human subjects. One important research theme is to understand the neural basis of learning in children and to identify ways that neuroscience could help to improve learning in the classroom. In collaboration with clinical colleagues, Gabrieli also seeks to use brain imaging to better understand, diagnose, and select treatments for neurological and psychiatric diseases.

Satrajit Ghosh

Personalized Medicine

A fundamental problem in psychiatry is that there are no biological markers for diagnosing mental illness or for indicating how best to treat it. Treatment decisions are based entirely on symptoms, and doctors and their patients will typically try one treatment, then if it does not work, try another, and perhaps another. Satrajit Ghosh hopes to change this picture, and his research suggests that individual brain scans and speaking patterns can hold valuable information for guiding psychiatrists and patients. His research group develops novel analytic platforms that use such information to create robust, predictive models around human health. Current areas include depression, suicide, anxiety disorders, autism, Parkinson’s disease, and brain tumors.

The Learning Brain

by Shannon Fischer |

“There’s a slogan in education,” says McGovern Investigator John Gabrieli. “The first three years are learning to read, and after that you read to learn.”

For John Gabrieli, learning to read represents one of the most important milestones in a child’s life. Except, that is, when a child can’t. Children who cannot learn to read adequately by the first grade have a 90 percent chance of still reading poorly in the fourth grade, and 75 percent odds of struggling in high school. For the estimated 10 percent of schoolchildren with a reading disability, that struggle often comes with a host of other social and emotional challenges: anxiety, damaged self-esteem, increased risk for poverty and eventually, encounters with the criminal justice system.

Most reading interventions focus on classical dyslexia, which is essentially a coding problem—trouble moving letters into sound patterns in the brain. But other factors, such as inadequate vocabulary and lack of practice opportunities, hinder reading too. The diagnosis can be subjective, and for those who are diagnosed, the standard treatments help only some students. “Every teacher knows half to two-thirds have a good response, the other third don’t,” Gabrieli says. “It’s a mystery. And amazingly there’s been almost no progress on that.”

For the last two decades, Gabrieli has sought to unravel the neuroscience behind learning and reading disabilities and, ultimately, convert that understanding into new and better education
interventions—a sort of translational medicine for the classroom.

The Home Effect

In 2011, when Julia Leonard was a research assistant in Gabrieli’s lab, she planned to go into pediatrics. But she became drawn to the lab’s education projects and decided to join the lab as
a graduate student to learn more. By 2015, she helped coauthor a landmark study with postdoc Allyson Mackey, that sought neural markers for the academic “achievement gap,” which separates higher socioeconomic status (SES) children from their disadvantaged peers. It was the first study to make a connection between SES-linked differences in brain structure and educational markers. Specifically, they found children from wealthier backgrounds had thicker cortical brain regions, which correlated with better academic achievement.

“Being a doctor is a really awesome and powerful career,” she says. “But I was more curious about the research that could cause bigger changes in children’s lives.”

Leonard collaborated with Rachel Romeo, another graduate student in the Gabrieli lab who wanted to understand the powerful effect of SES on the developing brain. Romeo had a distinctive background in speech pathology and literacy, where she’d observed wealthier students progressing more quickly compared to their disadvantaged peers.

Their research is revealing a fascinating picture. In a 2017 study, Romeo compared how reading-disabled children from low and high SES backgrounds fared after an intensive summer reading intervention. Low SES children in the intervention improved most in their reading, and MRI scans revealed their brains also underwent greater structural changes in response to the intervention. Higher SES children did not appear to change much, either in skill or brain structure.

“In the few studies that have looked at SES effects on treatment outcomes,” Romeo says, “the research suggests that higher SES kids would show the most improvement. We were surprised to
find that this wasn’t true.” She suspects that the midsummer timing of the intervention may account for this. Lower SES kids’ performance often suffer most during a “summer slump,”
and would therefore have the greatest potential to improve from interventions at this time.

However, in another study this year, Leonard uncovered unique brain differences in lower-SES children. Only among lower-SES children was better reasoning ability associated with thicker
cortex in a key part of the brain. Same behavior, different neural signatures.

“So this becomes a really interesting basic science question,” Leonard says. “Does the brain support cognition the same way across everyone, or does it differ based on how you grow up?”

Not a One-Size-Fits-All

Critics of such “educational neuroscience” have highlighted the lack of useful interventions produced by this research. Gabrieli agrees that so far, little has emerged. “The painful thing is the slowness of this work. It’s mind-boggling,” Gabrieli admits. Every intervention requires all the usual human research requirements, plus coordinating with schools, parents, teachers, and so on. “It’s a huge process to do even the smallest intervention,” he explains. Partly because of that, the field is still relatively new.

But he disagrees with the idea that nothing will come from this research. Gabrieli’s lab previously identified neural markers in children who will go on to develop reading disabilities. These markers could even predict who would or would not respond to standard treatments that focus on phonetic letter-sound coding.

Romeo and Leonard’s work suggests that varied etiologies underlie reading disabilities, which may be the key. “For so long people have thought that reading disorders were just a unitary construct: kids are bad at reading, so let’s fix that with a one-size-fits-all treatment,” Romeo says.

Such findings may ultimately help resource-strapped schools target existing phonetic training rather than enrolling all struggling readers in the same program, to see some still fail.

Think Spaces

At the Oliver Hazard Perry School, a public K-8 school located on the South Boston waterfront, teachers like Colleen Labbe have begun to independently navigate similar problems as they try
to reach their own struggling students.

“A lot of times we look at assessments and put students in intervention groups like phonics,” Labbe says. “But it’s important to also ask what is happening for these students on their way to school and at home.”

For Labbe and Perry Principal Geoffrey Rose, brain science has proven transformative. They’ve embraced literature on neuroplasticity—the idea that brains can change if teachers find the right combination of intervention and circumstances, like the low-SES students who benefited in Romeo and Leonard’s study.

“A big myth is that the brain can’t grow and change, and if you can’t reach that student, you pass them off,” Labbe says.

The science has also been empowering to her students, validating their own powers of self-change. “I tell the kids, we’re going to build the goop!” she says, referring to the brain’s ability to make new connections.

“All kids can learn,” Rose agrees. “But the flip of that is, can all kids do school?” His job, he says, is to make sure they can.

The classrooms at Perry are a mix of students from different cultures and socioeconomic backgrounds, so he and Labbe have focused on helping teachers find ways to connect with these children and help them manage their stresses and thus be ready to learn. Teachers here are armed with “scaffolds”—digestible neuro- and cognitive science aids culled from Rose’s postdoctoral studies at Boston College’s Professional School Administrator Program for school leaders. These encourage teachers to be more aware of cultural differences and tendencies in themselves and their students, to better connect.

There are also “Think Spaces” tucked into classroom corners. “Take a deep breath and be calm,” read posters at these soothing stations, which are equipped with de-stressing tools, like squeezable balls, play-dough, and meditation-inspiring sparkle wands. It sounds trivial, yet studies have shown that poverty-linked stressors like food and home insecurity take a toll on emotion and memory-linked brain areas like the amygdala and hippocampus.

In fact, a new study by Clemens Bauer, a postdoc in Gabrieli’s lab, argues that mindfulness training can help calm amygdala hyperactivity, help lower self-perceived stress, and boost attention. His study was conducted with children enrolled in a Boston charter school.

Taking these combined approaches, Labbe says, she’s seen one of her students rise from struggling at the lowest levels of instruction, to thriving by year end. Labbe’s focus on understanding the girl’s stressors, her family environment, and what social and emotional support she really needed was key. “Now she knows she can do it,” Labbe says.

Rose and Labbe only wish they could better bridge the gap between educators like themselves and brain scientists like Gabrieli. To help forge these connections, Rose recently visited Gabrieli’s lab and looks forward to future collaborations. Brain research will provide critical insights into teaching strategy, he says, but the gap is still wide.

From Lab to Classroom

“I’m hugely impressed by principals and teachers who are passionately interested in understanding the brain,” Gabrieli says. Fortunately, new efforts are bridging educators and scientists.

This March, Gabrieli and the MIT Integrated Learning Initiative—MITili, which he also directs—announced a $30 million-dollar grant from the Chan Zuckerberg Initiative for a collaboration
between MIT, the Harvard Graduate School of Education, and Florida State University.

The grant aims to translate some of Gabrieli’s work into more classrooms. Specifically, he hopes to produce better diagnostics that can identify children at risk for dyslexia and other learning
disabilities before they even learn to read.

He hopes to also provide rudimentary diagnostics that identify the source of struggle, be it classic dyslexia, lack of home support, stress, or maybe a combination of factors. That in turn,
could guide treatment—standard phonetic care for some children, versus alternatives: social support akin to Labbe’s efforts, reading practice, or maybe just vocabulary-boosting conversation time with adults.

“We want to get every kid to be an adequate reader by the end of the third grade,” Gabrieli says. “That’s the ultimate goal for me: to help all children become learners.”

Back-and-forth exchanges boost children’s brain response to language

Anne Trafton |

A landmark 1995 study found that children from higher-income families hear about 30 million more words during their first three years of life than children from lower-income families. This “30-million-word gap” correlates with significant differences in tests of vocabulary, language development, and reading comprehension.

MIT cognitive scientists have now found that conversation between an adult and a child appears to change the child’s brain, and that this back-and-forth conversation is actually more critical to language development than the word gap. In a study of children between the ages of 4 and 6, they found that differences in the number of “conversational turns” accounted for a large portion of the differences in brain physiology and language skills that they found among the children. This finding applied to children regardless of parental income or education.

The findings suggest that parents can have considerable influence over their children’s language and brain development by simply engaging them in conversation, the researchers say.

“The important thing is not just to talk to your child, but to talk with your child. It’s not just about dumping language into your child’s brain, but to actually carry on a conversation with them,” says Rachel Romeo, a graduate student at Harvard and MIT and the lead author of the paper, which appears in the Feb. 14 online edition of Psychological Science.

Using functional magnetic resonance imaging (fMRI), the researchers identified differences in the brain’s response to language that correlated with the number of conversational turns. In children who experienced more conversation, Broca’s area, a part of the brain involved in speech production and language processing, was much more active while they listened to stories. This brain activation then predicted children’s scores on language assessments, fully explaining the income-related differences in children’s language skills.

“The really novel thing about our paper is that it provides the first evidence that family conversation at home is associated with brain development in children. It’s almost magical how parental conversation appears to influence the biological growth of the brain,” says John Gabrieli, the Grover M. Hermann Professor in Health Sciences and Technology, a professor of brain and cognitive sciences, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study.

Beyond the word gap

Before this study, little was known about how the “word gap” might translate into differences in the brain. The MIT team set out to find these differences by comparing the brain scans of children from different socioeconomic backgrounds.

As part of the study, the researchers used a system called Language Environment Analysis (LENA) to record every word spoken or heard by each child. Parents who agreed to have their children participate in the study were told to have their children wear the recorder for two days, from the time they woke up until they went to bed.

The recordings were then analyzed by a computer program that yielded three measurements: the number of words spoken by the child, the number of words spoken to the child, and the number of times that the child and an adult took a “conversational turn” — a back-and-forth exchange initiated by either one.

The researchers found that the number of conversational turns correlated strongly with the children’s scores on standardized tests of language skill, including vocabulary, grammar, and verbal reasoning. The number of conversational turns also correlated with more activity in Broca’s area, when the children listened to stories while inside an fMRI scanner.

These correlations were much stronger than those between the number of words heard and language scores, and between the number of words heard and activity in Broca’s area.

This result aligns with other recent findings, Romeo says, “but there’s still a popular notion that there’s this 30-million-word gap, and we need to dump words into these kids — just talk to them all day long, or maybe sit them in front of a TV that will talk to them. However, the brain data show that it really seems to be this interactive dialogue that is more strongly related to neural processing.”

The researchers believe interactive conversation gives children more of an opportunity to practice their communication skills, including the ability to understand what another person is trying to say and to respond in an appropriate way.

While children from higher-income families were exposed to more language on average, children from lower-income families who experienced a high number of conversational turns had language skills and Broca’s area brain activity similar to those of children who came from higher-income families.

“In our analysis, the conversational turn-taking seems like the thing that makes a difference, regardless of socioeconomic status. Such turn-taking occurs more often in families from a higher socioeconomic status, but children coming from families with lesser income or parental education showed the same benefits from conversational turn-taking,” Gabrieli says.

Taking action

The researchers hope their findings will encourage parents to engage their young children in more conversation. Although this study was done in children age 4 to 6, this type of turn-taking can also be done with much younger children, by making sounds back and forth or making faces, the researchers say.

“One of the things we’re excited about is that it feels like a relatively actionable thing because it’s specific. That doesn’t mean it’s easy for less educated families, under greater economic stress, to have more conversation with their child. But at the same time, it’s a targeted, specific action, and there may be ways to promote or encourage that,” Gabrieli says.

Roberta Golinkoff, a professor of education at the University of Delaware School of Education, says the new study presents an important finding that adds to the evidence that it’s not just the number of words children hear that is significant for their language development.

“You can talk to a child until you’re blue in the face, but if you’re not engaging with the child and having a conversational duet about what the child is interested in, you’re not going to give the child the language processing skills that they need,” says Golinkoff, who was not involved in the study. “If you can get the child to participate, not just listen, that will allow the child to have a better language outcome.”

The MIT researchers now hope to study the effects of possible interventions that incorporate more conversation into young children’s lives. These could include technological assistance, such as computer programs that can converse or electronic reminders to parents to engage their children in conversation.

The research was funded by the Walton Family Foundation, the National Institute of Child Health and Human Development, a Harvard Mind Brain Behavior Grant, and a gift from David Pun Chan.

Socioeconomic background linked to reading improvement

by Anne Trafton |

About 20 percent of children in the United States have difficulty learning to read, and educators have devised a variety of interventions to try to help them. Not every program helps every student, however, in part because the origins of their struggles are not identical.

MIT neuroscientist John Gabrieli is trying to identify factors that may help to predict individual children’s responses to different types of reading interventions. As part of that effort, he recently found that children from lower-income families responded much better to a summer reading program than children from a higher socioeconomic background.

Using magnetic resonance imaging (MRI), the research team also found anatomical changes in the brains of children whose reading abilities improved — in particular, a thickening of the cortex in parts of the brain known to be involved in reading.

“If you just left these children [with reading difficulties] alone on the developmental path they’re on, they would have terrible troubles reading in school. We’re taking them on a neuroanatomical detour that seems to go with real gains in reading ability,” says Gabrieli, the Grover M. Hermann Professor in Health Sciences and Technology, a professor of brain and cognitive sciences, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study.

Rachel Romeo, a graduate student in the Harvard-MIT Program in Health Sciences and Technology, and Joanna Christodoulou, an assistant professor of communication sciences and disorders at the Massachusetts General Hospital Institute of Health Professions, are the lead authors of the paper, which appears in the June 7 issue of the journal Cerebral Cortex.

Predicting improvement

In hopes of identifying factors that influence children’s responses to reading interventions, the MIT team set up two summer schools based on a program known as Lindamood-Bell. The researchers recruited students from a wide income range, although socioeconomic status was not the original focus of their study.

The Lindamood-Bell program focuses on helping students develop the sensory and cognitive processing necessary for reading, such as thinking about words as units of sound, and translating printed letters into word meanings.

Children participating in the study, who ranged from 6 to 9 years old, spent four hours a day, five days a week in the program, for six weeks. Before and after the program, their brains were scanned with MRI and they were given some commonly used tests of reading proficiency.

In tests taken before the program started, children from higher and lower socioeconomic (SES) backgrounds fared equally poorly in most areas, with one exception. Children from higher SES backgrounds had higher vocabulary scores, which has also been seen in studies comparing nondyslexic readers from different SES backgrounds.

“There’s a strong trend in these studies that higher SES families tend to talk more with their kids and also use more complex and diverse language. That tends to be where the vocabulary correlation comes from,” Romeo says.

The researchers also found differences in brain anatomy before the reading program started. Children from higher socioeconomic backgrounds had thicker cortex in a part of the brain known as Broca’s area, which is necessary for language production and comprehension. The researchers also found that these differences could account for the differences in vocabulary levels between the two groups.

Based on a limited number of previous studies, the researchers hypothesized that the reading program would have more of an impact on the students from higher socioeconomic backgrounds. But in fact, they found the opposite. About half of the students improved their scores, while the other half worsened or stayed the same. When analyzing the data for possible explanations, family income level was the one factor that proved significant.

“Socioeconomic status just showed up as the piece that was most predictive of treatment response,” Romeo says.

The same children whose reading scores improved also displayed changes in their brain anatomy. Specifically, the researchers found that they had a thickening of the cortex in a part of the brain known as the temporal occipital region, which comprises a large network of structures involved in reading.

“Mix of causes”

The researchers believe that their results may have been different than previous studies of reading intervention in low SES students because their program was run during the summer, rather than during the school year.

“Summer is when socioeconomic status takes its biggest toll. Low SES kids typically have less academic content in their summer activities compared to high SES, and that results in a slump in their skills,” Romeo says. “This may have been particularly beneficial for them because it may have been out of the realm of their typical summer.”

The researchers also hypothesize that reading difficulties may arise in slightly different ways among children of different SES backgrounds.

“There could be a different mix of causes,” Gabrieli says. “Reading is a complicated skill, so there could be a number of different factors that would make you do better or do worse. It could be that those factors are a little bit different in children with more enriched or less enriched environments.”

The researchers are hoping to identify more precisely the factors related to socioeconomic status, other environmental factors, or genetic components that could predict which types of reading interventions will be successful for individual students.

“In medicine, people call it personalized medicine: this idea that some people will really benefit from one intervention and not so much from another,” Gabrieli says. “We’re interested in understanding the match between the student and the kind of educational support that would be helpful for that particular student.”

The research was funded by the Ellison Medical Foundation, the Halis Family Foundation, Lindamood-Bell Learning Processes, and the National Institutes of Health.

Distinctive brain pattern may underlie dyslexia

Anne Trafton |

A distinctive neural signature found in the brains of people with dyslexia may explain why these individuals have difficulty learning to read, according to a new study from MIT neuroscientists.

The researchers discovered that in people with dyslexia, the brain has a diminished ability to acclimate to a repeated input — a trait known as neural adaptation. For example, when dyslexic students see the same word repeatedly, brain regions involved in reading do not show the same adaptation seen in typical readers.

This suggests that the brain’s plasticity, which underpins its ability to learn new things, is reduced, says John Gabrieli, the Grover M. Hermann Professor in Health Sciences and Technology, a professor of brain and cognitive sciences, and a member of MIT’s McGovern Institute for Brain Research.

“It’s a difference in the brain that’s not about reading per se, but it’s a difference in perceptual learning that’s pretty broad,” says Gabrieli, who is the study’s senior author. “This is a path by which a brain difference could influence learning to read, which involves so many demands on plasticity.”

Former MIT graduate student Tyler Perrachione, who is now an assistant professor at Boston University, is the lead author of the study, which appears in the Dec. 21 issue of Neuron.

Reduced plasticity

The MIT team used magnetic resonance imaging (MRI) to scan the brains of young adults with and without reading difficulties as they performed a variety of tasks. In the first experiment, the subjects listened to a series of words read by either four different speakers or a single speaker.

The MRI scans revealed distinctive patterns of activity in each group of subjects. In nondyslexic people, areas of the brain that are involved in language showed neural adaption after hearing words said by the same speaker, but not when different speakers said the words. However, the dyslexic subjects showed much less adaptation to hearing words said by a single speaker.

Neurons that respond to a particular sensory input usually react strongly at first, but their response becomes muted as the input continues. This neural adaptation reflects chemical changes in neurons that make it easier for them to respond to a familiar stimulus, Gabrieli says. This phenomenon, known as plasticity, is key to learning new skills.

“You learn something upon the initial presentation that makes you better able to do it the second time, and the ease is marked by reduced neural activity,” Gabrieli says. “Because you’ve done something before, it’s easier to do it again.”

The researchers then ran a series of experiments to test how broad this effect might be. They asked subjects to look at series of the same word or different words; pictures of the same object or different objects; and pictures of the same face or different faces. In each case, they found that in people with dyslexia, brain regions devoted to interpreting words, objects, and faces, respectively, did not show neural adaptation when the same stimuli were repeated multiple times.

“The brain location changed depending on the nature of the content that was being perceived, but the reduced adaptation was consistent across very different domains,” Gabrieli says.

He was surprised to see that this effect was so widespread, appearing even during tasks that have nothing to do with reading; people with dyslexia have no documented difficulties in recognizing objects or faces.

He hypothesizes that the impairment shows up primarily in reading because deciphering letters and mapping them to sounds is such a demanding cognitive task. “There are probably few tasks people undertake that require as much plasticity as reading,” Gabrieli says.

Early appearance

In their final experiment, the researchers tested first and second graders with and without reading difficulties, and they found the same disparity in neural adaptation.

“We got almost the identical reduction in plasticity, which suggests that this is occurring quite early in learning to read,” Gabrieli says. “It’s not a consequence of a different learning experience over the years in struggling to read.”

Gabrieli’s lab now plans to study younger children to see if these differences might be apparent even before children begin to learn to read. They also hope to use other types of brain measurements such as magnetoencephalography (MEG) to follow the time course of the neural adaptation more closely.

The research was funded by the Ellison Medical Foundation, the National Institutes of Health, and a National Science Foundation Graduate Research Fellowship.