Dyslexia: Biological Marker Discovered

Though learning to read proceeds smoothly for most children, as many as one in 10 is estimated to suffer from dyslexia, a constellation of impairments unrelated to intelligence, hearing or vision that make learning to read a struggle.

Now, Northwestern University researchers report they have found a biological mechanism that appears to play an important role in the reading process.

"We discovered a systematic relationship between reading ability and the consistency with which the brain encodes sounds," says Nina Kraus, Hugh Knowles Professor of Neurobiology, Physiology and Communication.

"Unstable Representation of Sound: A Biological Marker of Dyslexia," co-authored by Jane Hornickel, will appear in the Feb. 20 issue of The Journal of Neuroscience.

Recording the automatic brain wave responses of 100 school-aged children to speech sounds, the Northwestern researchers found that the very best readers encoded the sound most consistently while the poorest readers encoded it with the greatest inconsistency.

Presumably, the brain's response to sound stabilises when children learn to successfully connect sounds with their meanings.

Happily biology is not destiny. In prior work in Northwestern's Auditory Neuroscience Laboratory, Kraus and her colleagues found that the inconsistency with which the poorest readers encode sound could be "fixed" through training.

In that study, children with reading impairments were fitted for a year with assistive listening devices that transmitted their teacher's voice directly into their ears.

After a year, the children showed improvement not only in reading but also in the consistency with which their brains encoded speech sounds, particularly consonants.

"Use of the devices focused youngsters' brains on the "meaningful" sounds coming from their teacher, diminishing other, extraneous distractions," said Kraus.

"After a year of use, the students had honed their auditory systems and no longer required the assistive devices to keep their reading and encoding advantage."

People rarely have difficulty encoding vowel sounds, which are relatively simple and long, according to Kraus. It is consonant sounds -- sounds which are shorter and more acoustically complex -- that are most likely to be incorrectly categorized by the brain.

"Understanding the biological mechanisms of reading puts us in a better position to both understand how normal reading works and to ameliorate it where it goes awry," says Kraus.

"Our results suggest that good readers profit from a stable neural representation of sound, and that children with inconsistent neural responses are likely at a disadvantage when learning to read," Kraus adds.

"The good news is that response consistency can be improved with auditory training."

Decades of research from laboratories worldwide have shown that reading ability is associated with auditory skills, including auditory memory and attention, the ability to rhyme sounds and the ability to categorise rapidly occurring sounds.

Dyslexia: Music Ability Helps Reading

Playing a musical instrument from a young age appears to create new pathways in the brain that process written words and letters, reports Ann Lukits in the Wall Street Journal.

The findings, which may help children with reading disorders such as dyslexia, appeared in the journal Neuropsychologia.

“Fifteen professional musicians who had played an instrument since childhood and 15 control subjects who couldn’t read music participated in two experiments in Milan. Subjects were 26 to 31 years old.

In one experiment, subjects pressed a button if they recognized the notes E, F, G, A and B (mi, fa, sol, la and ti on the musical scale) which randomly appeared in 300 short musical scores flashed on a computer screen.

In the other experiment, they pressed the button when they spotted the letters B, G, L, M and S in 300 randomly selected words. An electroencephalogram (EEG) measured brain-wave activity. Musicians recognized notes significantly faster than controls; letters, only slightly faster. Musicians made fewer errors in both experiments.

But EEG results showed striking differences. In musicians, reading musical notes and words activated both the left and right sides of the brain, whereas in controls, only the left side responded to words and the right side to notes.

Language is normally a left-brain function and music a right-brain function. The involvement of the right side in a typically left-sided function probably resulted from reading music, researchers said. Musical training may be quite helpful for children struggling to read, they said.”

Read more here

Dyslexia Defined: Divergence in IQ and Reading ability

This graph shows the divergence between IQ and Reading ability in dyslexics.

It also shows that IQ and reading ability track together in typical readers.

Credit: Sally and Bennett Shaywitz, Yale University, Psychological Science.

For health workers, parents and guardians of children who suffer from Dyslexia it has long been known that these children are highly intelligent, despite there learning disorder. Some would say that they are above average in intelligence.

Accomplished People
Contrary to popular belief, some very famous and accomplished people cannot read well. This arguably, unexpected difficulty in reading, in relation to intelligence, education and professional status is called dyslexia.

Recent psychological research at Yale School of Medicine and University of California Davis, have presented new data that may help to explain why some bright and intelligent people struggle to read.

The Journal of Psychological Science
In January 1, 2010, the study will be published in the journal Psychological Science, and it promises to provide a validated definition of dyslexia. "For the first time, we've found empirical evidence that shows the relationship between IQ and reading over time differs for typical compared to dyslexic readers," said Sally E. Shaywitz, M.D., the Audrey G. Ratner Professor in Learning Development at Yale School of Medicine's Department of Pediatrics, and co-director of the newly formed Yale Center for Dyslexia and Creativity.

Cognitive v Reading
Using data from the Connecticut Longitudinal Study, an ongoing 12-year study of cognitive and behavioral development in a representative sample of 445 Connecticut schoolchildren, Shaywitz and her team tested each child in reading every year and tested for IQ every other year. They were looking for evidence to show how the dissociation between cognitive ability and reading ability might develop in children.

Tracking
The researchers found that in typical readers, IQ and reading not only track together, but also influence each other over time but in children who suffer from dyslexia, IQ and reading are not linked over time and do not influence one another. Thus confirming that a dyslexic child can be both bright and not read well.

Uncoupling
Like so many others who are working with children who suffer from Dyslexia, Shaywitz said "I've seen so many children who have a high IQ but are struggling to read. Our findings of an uncoupling between IQ and reading, and the influence of this uncoupling on the developmental trajectory of reading, provide confirmational evidence to support the concept that dyslexia is an unexpected difficulty with reading in children who otherwise have the intelligence to learn to read."

Reading Not automatic
Typical readers learn how to associate letters with a specific sound. "All they have to do is look at the letters and it's automatic," Shaywitz explained. "It's like breathing; you don't have to tell your lungs to take in air. In dyslexia, this process remains manual." Each time a dyslexic sees a word, it's as if they've never seen it before. People with dyslexia have to read slowly, re-read, and sometimes use a marker so they don't lose their place.

A Disparity
"A key characteristic of dyslexia is that the unexpected difficulty refers to a disparity within the person rather than, for example, a relative weakness compared to the general population," said co-author Bennett A. Shaywitz, M.D., the Charles and Helen Schwab Professor in Dyslexia and Learning Development and co-director of the Yale Center for Dyslexia and Creativity.

One in Five
Sally Shaywitz estimates that one in five people are dyslexic and points to many accomplished writers, physicians and attorneys with dyslexia who struggle with the condition in their daily lives. This long list of famous and accomplished people includes Carol Greider, the 2009 Nobel laureate in medicine. She hopes to dispel many of the myths surrounding the condition.

High Performing
"High-performing people who suffer from Dyslexia, are very intelligent, often innovative, lateral thinkers and therefore, great problem-solvers," she said. "The neural signature for dyslexia is seen in children and adults. You cannot run away from or outgrow dyslexia, it is with you for life and you need to learn the best way to deal with that."

Words: Spoken and Written
Shaywitz also stresses that the problem is with both basic spoken and written language. People with dyslexia may need time to retrieve words, so they might not speak or read as fluidly as others.

Stress and Anxiety
An increases in levels of stress and anxiety, can make dealing with the effect of dyslexia worse. The time pressure around standardised tests like the SATs and entrance exams for professional schools, so the need for support and accommodations is key in helping those with the disorder realise their potential, she says.

Don't Panic!
If you do have concerns about a child or an adult who is suffering from Dyslexia consult a qualified consultant. Meantime, feel free to leave your comments about this article and don't hesitate to let me know of your success stories and concerns.