Dyslexia at MIT by Lydia K. '14, MEng '16

This is my final paper for Science Journalism, a science writing class I took last semester. Reading the literature and interviewing people for this paper taught me a lot about a subject that is central in many people’s lives but about which I knew almost nothing when I started, and maybe even more about myself as a writer and a person. I thought you might enjoy it, for a glimpse of a hot field as well as a bit of the research, diversity, and student support services at MIT.

   

Y is a third-year undergraduate student at MIT, a math major and one of only five current MIT undergraduate students from the United Kingdom. To have gotten to MIT she had to face not only the 3.7% international admit rate, but also dyslexia, a learning disorder that prevents her from reading and writing as quickly and effectively as most of her peers.

A short paragraph can take Y half an hour to type. She says that the words that come out on paper or on the screen do not match up with what she envisions in her mind. It takes her more time to read and write than other students, and she has to spend extra time on problem sets and essays.

Like many successful people with dyslexia, Y sees her difficulty reading and writing as something to conquer. She has taken on a concentration in writing, which requires her to take extra writing classes in her time at MIT, and she volunteers for leadership positions in her dorm that involve regularly emailing the entire building. After graduating she hopes to return to the United Kingdom for graduate school.

The ability to read has long been linked in society’s mind to intelligence, but dyslexia is surprisingly common at MIT, to such an extent that the founder of the MIT Media Lab and the One Laptop per Child Association, Nicholas Negroponte (a dyslexic himself), called it the MIT disease in his autobiography. Recent research has found that dyslexia is not related to IQ. It is, however, the most common learning disability, at MIT and elsewhere, affecting between 5% and 20% of the population.

The latest research is finding dyslexia’s roots in unexpected places, with unexpected consequences, disproving common misconceptions about dyslexia and learning disorders in general. We are beginning to find that dyslexia is not a disorder but a different way of experiencing and understanding the world around us, created by a different wiring and development of the brain with benefits as significant as its downsides.

Dyslexia Research

A popular misconception is that people with dyslexia rotate, switch, and mirror letters as they read and write, but while many people with dyslexia do indeed confuse the direction and sequence of letters, dyslexia stems from difficulty processing the auditory, not visual, information of language. It is currently believed that dyslexia is caused by difficulty connecting letters to their associated sounds, and that these phonological difficulties stem from structural differences in the brain.

Y, for example, connects sounds to colors, rather than symbols. Imagining a sound brings to mind not the letter, but a color. Each sound has its own color: the calming light blue she painted her dorm room is the long e.

Tyler Perrachione, a dyslexia researcher at MIT, explains that all children flip and switch letters as they first learn to read, and that the difficulty is not specific to people with dyslexia. “In life, you want to be insensitive to the orientation of objects,” he says. “Orthography is set apart from other visual stimuli. They [children] have to learn that letters are special.” In languages where symbols represent concepts rather than sounds, such as Chinese, a larger number of dyslexics do suffer from a visual deficit. But even in China, says Perrachione, visual deficits are always present in combination with a phonological deficit, never in isolation.

Tyler Perrachione became interested in speech-sound learning as an undergraduate student, and is now studying dyslexia as a Ph.D. candidate at the Gabrieli lab at MIT. He describes studying language as “learning about what makes us human, and what makes our brains unique: moving ideas from my head to your head. I was hooked. Language was cool.”

Perrachione’s most recent publication focuses on how people with dyslexia process auditory language. He explains that while speakers of a language may use the same words, pronunciation of those words is unique to the individual. We use these nuances in pronunciation to distinguish between voices. Perrachione found that people with dyslexia have trouble with voice recognition in their native language. Previous studies have found that people with dyslexia have difficulty following a single voice in a crowd, such as the voice of a professor in a noisy lecture hall.

As babies we are sensitive to all variability in speech sounds, explains Perrachione. As we grow up we lose sensitivity to those nuances that are not in our native language. “The brain is so good at handling all the variability that there is in speech,” he says, “but it comes with a cost. Being very good at mapping sounds to the representations that you do have comes with the cost of not being able to perceive sounds in other languages.”

We don’t consciously notice the variability in language, but the brain does not ignore it, says Perrachione. “The brain can keep track of who is saying what, and how they sound is the cue to who they are.” Knowing a language gives us a standard against which to compare what we hear, he says: “Being able to say people sound different requires having some sort of comparison.” People with dyslexia do not have this comparison: “The variability is not informative, because you don’t have a standard to compare it to.”

In Perrachione’s experiment, normal readers had improved voice recognition abilities in their native languages. People with dyslexia, on the other hand, had no more accuracy than in foreign languages, where the nuances in sound were unfamiliar. “When you take language out of the equation they’re just as good. When you put language back in, they’re no better.”

The differences between how people with dyslexia and normal readers process language are evident in the anatomy of the brain. In both cases, the left hemisphere of the brain contains centers for speech, reading, and language processing. The connective fiber attaching the hearing centers in the temporal lobe with the parietal lobe becomes denser as a person’s ability to hear and identify small units of sound—as well as the ability to read—improves. This area of the brain, located toward the back of the head, is responsible for decoding letters and written words into their corresponding sounds; anatomical studies have found that dyslexics have decreased nerve cell matter and often decreased connective fiber in this area compared to normal readers.

The right hemisphere of the brain—specifically, the right prefrontal cortex, which is located at the front of the head—produces visual images. Individuals without dyslexia suppress the visual areas of the right hemisphere while reading, as originally hypothesized in 1925 and confirmed in 2003 by researchers at Georgetown University Medical Center. Normal readers use the right prefrontal cortex less and less as they learn to read fluently and shift from reading by memorizing words to reading by translating letters into sounds. Perrachione’s advisor John Gabrieli at MIT and Fumiko Hoeft of the Stanford University School of Medicine have found that the quarter to half of dyslexic children who learn to compensate for their dyslexia read by memorizing words through visual memory, increasing the activity and development of the right prefrontal cortex. In normal readers, the left side of the brain is often larger than the right. In dyslexic readers the two hemispheres are usually of equal size, or the right hemisphere is larger.

Manuel Casanova at the University of Louisville, Kentucky, has found that dyslexics also tend to have less tightly packed neurons that make more far-reaching connections. Casanova found that neurons vary from tightly packed, encouraging connections with nearby neurons, to more spread out, providing space for more distant connections. At the former extreme, neurons make more of their connections with nearby neurons and can process information very quickly. The resulting person is often highly specialized and detail-oriented, and can be autistic. At the other extreme, neurons make more of their connections with distant parts of the brain, supporting complex comparisons and mental simulations. This end of the spectrum has high incidence of dyslexia.

Perrachione warns, however, that studies linking differences in the anatomy of the brain to differences in behavior are rarely replicated and often don’t stand up to scientific scrutiny, and should therefore be viewed with some amount of skepticism. “Excluding injury in adult life,” he says, “very big changes in behavior are almost never explained by big changes in brain architecture.”

Living with Dyslexia

There is hope for treating dyslexia at an early age. In 2008, Nadine Gaab at the Children’s Hospital Boston found that rapid sound shifts in spoken language generated activity in areas of the brain associated with sound recognition in normal 10-year-olds, but elicited no activity from children with dyslexia. After two months of exercising these areas of the brain, however, the dyslexic children were able to match the normal children in listening comprehension, and also had improved reading comprehension.

Dyslexia often goes undiagnosed until college or graduate school, when the length and difficulty of assigned readings make it difficult to compensate with sheer intelligence. If diagnosed as an undergraduate, an MIT student would be referred to student support services, to disability services, and then to a neuropsychologist for testing. MIT has services in place to help students with dyslexia, including exams and textbooks on tape, readers, scribes, a computer lab with voice recognition and scan-and-read software, and the option to take exams in a reduced distraction setting or with extended time.

Dr. Xiaolu His, a psychologist at MIT Mental Health and Counseling, says that many people with dyslexia find life much easier after entering the workforce, where tasks become less time-sensitive and being able to read and write quickly becomes less important. Instead, creativity and flexible thinking become vital, and people with dyslexia who are able to get so far often excel. She encourages students with dyslexia to get the help they need. “Once the problem is identified, you will find your solution,” says His. “It does not have to cripple you for life.”

Benefits of Dyslexia

“Everything that happens has a silver lining,” says Perrachione. Dyslexia’s is often a predisposition for creativity and big-picture thinking. “Their ways of thinking can be extremely useful,” says His of her dyslexic patients. “Some of them are just among the most creative, exciting innovating people I’ve ever met.”

Many people with dyslexia go into comedy, says Perrachione, citing Jay Leno and writers for the Saturday Night Live comedy show. A recent study also found that astronomers with dyslexia are better at identifying black holes: people with dyslexia have enhanced peripheral vision, improved pattern recognition abilities, and, says Perrachione, more creativity and flexibility in their thinking.

According to Brook and Fernette Eide, authors of The Dyslexic Advantage, the cognitive flexibility associated with dyslexia can manifest itself in noteworthy talents. “Dyslexic brains are organized in a way that maximizes strength in making big picture connections at the expense of weaknesses in processing fine details,” says Fernette Eide. These talents include improved spatial reasoning, enhanced ability to view events from multiple perspectives and draw analogies, and a tendency to remember facts as experiences and stories rather than as abstractions. Individuals with dyslexia often excel in careers that involve telling and understanding stories, making predictions or decisions using incomplete or rapidly changing information, and crossing boundaries between disciplines and ways of thinking. “High-performing dyslexics are very intelligent, often out-of-the box thinkers and problem-solvers,” says Bennet A. Shaywitz, co-director of the Yale Center for Dyslexia and Creativity.

It is important for us to stop seeing dyslexia as a learning disability and start seeing it as an alternative way of perceiving and processing the world, with benefits as well as drawbacks, and with the potential to contribute creative approaches to our world’s problems. We have only just begun unraveling the secrets of the dyslexic mind. We know now that phonological impairment leads to dyslexia. The next step, says Perrachione, is to figure out how. Current research in the Gabrielli lab is focusing on measuring brain plasticity and responsiveness to changes in sound. The data will be out soon, says Perrachione, after it goes through peer review. “I think they [the data] have a lot of promise for really revolutionizing how we talk about the phonological deficit in dyslexia,” he says. “They’re very exciting. You can expect to see new discoveries soon.”