![[What We Now Know]](graphics/weknow.GIF) |
What We Now Know
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NIH Research Project
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In the early 1980's, the United
States Congress mandated the National Institutes of Health to
research learning disabilities and answer seven specific questions.
After conducting longitudinal
research plus numerous studies on genetics, interventions,
and brain function, we now have a great deal of independent, scientific, replicated, published research on dyslexia.
This page shares the research results released
by the National Institutes of Health from 1994 to the present, as well as from dyslexia researchers in several others countries.
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NIH Research Questions
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NIH coordinated 18 top-notch university research
teams throughout the United States to answer the following questions
posed by Congress:
- How many children are learning disabled?
- Clearly define each specific type of learning
disability.
- What causes each learning disability?
- How can we identify each learning disability?
- How long does each disability last? Map its
developmental course.
- What is the best way to teach these children?
- Can we prevent any of these learning disabilities?
NIH investigated dyslexia first because it
is the most prevalent learning disability.
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NIH Results Released in 1994
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These research results have been independently
replicated and are now considered to be irrefutable.
- Dyslexia affects at least 1 out of every
5 children in the United States.
- Dyslexia represents the most common and prevalent
of all known learning disabilities.
- Dyslexia is the most researched of all learning
disabilities.
- Dyslexia affects as many boys as girls.
- Some forms of dyslexia are highly heritable.
- Dyslexia is the leading cause of reading
failure and school dropouts in our nation.
- Reading failure is the most commonly shared
characteristic of juvenile justice offenders.
- Dyslexia has been shown to be clearly related
to neurophysiological differences in brain function. Dyslexic
children display difficulty with the sound/symbol correspondences
of our written code because of these differences in brain function.
- Early intervention is essential for this
population.
- Dyslexia is identifiable, with 92% accuracy,
at ages 5 1/2 to 6 1/2.
- Dyslexia is primarily due to linguistic deficits.
We now know dyslexia is due to a difficulty processing language.
It is not due to visual problems, and people with dyslexia do
not see words or letters backwards.
- Reading failure caused by dyslexia is highly
preventable through direct, explicit instruction in phonemic
awareness.
- Children do not outgrow reading failure or
dyslexia.
- Of children who display reading problems
in the first grade, 74% will be poor readers in the ninth grade
and into adulthood unless they receive informed and explicit
instruction on phonemic awareness.
Children do not mature out of their reading difficulties.
- Research evidence does not support the use
of "whole language" reading approaches to teach dyslexic
children.
- Dyslexia and ADD are two separate and identifiable
entities.
- Dyslexia and ADD so frequently coexist within
the same child that it is always best to test for both.
- Children with both dyslexia and ADD are at
dramatically increased risk for substance abuse and felony convictions
if they do not receive appropriate interventions.
- The current "discrepancy model"
testing utilized by our nation's public schools to establish
eligibility for special education services is not a valid diagnostic
marker for dyslexia.
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Research Results Released After 1994
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- Word recognition difficulties are the most
reliable indicators of reading disability in older children and
adults. Slow, labored, and inaccurate reading of real and nonsense
words in isolation are key warning signs.
- This laborious reading of single words frequently
impedes the individual's ability to comprehend what has been
read, even though listening comprehension is adequate.
- Even among children and adults who score
within normal ranges on reading achievement tests, many report
that reading is so laborious and unproductive that they rarely
read either for learning or for pleasure.
- Developing adequate awareness of phonemes
is not dependent on intelligence, socio-economic status, or parents'
education, but can be fostered through direct, explicit instruction.
Such instruction is shown to accelerate reading acquisition in
general, even as it reduces the incidence of reading failure.
- Disabled readers must be provided highly
structured programs that explicitly teach application of phonologic rules to print. Longitudinal
data (studies that follow children over time) indicate that explicit
systematic phonics instruction
results in more favorable outcomes for disabled readers than
does a context-emphasis (whole-language) approach.
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Longitudinal Research
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The National Institutes of Health conducted
a longitudinal study by tracking 5,000 children at random from
all over the country starting when they were 4 years old until
they graduated from high school. The researchers had no idea
which children would develop reading difficulties and which ones
would not.
There were many theories at that time as to
what caused reading difficulties, and which tests best predicted
reading failure. The researchers tested these children 3 times
a year for 14 years using a variety of tests that would either
support or disprove the competing theories. But the researchers
did NOT provide any type of training or intervention. They simply
watched and tested.
From that research, they were able to determine
which tests are most predictive of reading failure, at what age
we can test children, and whether children outgrow their reading
difficulties. This study also spawned numerous other NIH research
projects. The results of these studies
were released in 1994.
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Speech Delays
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Speech delays turn into reading problems
excerpt of an article called
The Relationship Between Language and Learning Disabilities
on the LDOnline.org website
In 1980, Snyder predicted that the language-delayed preschooler of today may well become the learning-disabled child of tomorrow. A growing body of evidence supports her prediction and suggests that many of these children do not "outgrow" these problems, and that "simple" delays in communication may, in fact, be stable predictors of later learning disabilities.
One set of researchers followed a group of children from ages 2 to 6. The children were identified at age 2 as "late talkers." Although the majority outgrew their oral language delay by age 4, they demonstrated academic delays at ages 5 and 6.
Another set of researchers found that the oral language disorders decreased over time, giving the impression of "recovery" by age 5. However, the majority of those children experienced reading disabilities by grade 2.
To read the entire article, go to:
www.dys-add.com/LanguageDelayandLD.pdf
Detecting dyslexia in preschoolers
excerpt of study published in Science Daily
published August 22, 2008
reported on www.sciencedaily.com
Atypical characteristics of children's linguistic development are early signs of the risk of dyslexia, and new research points to preventive exercises as an effective means to tackle the challenges children face when learning to read.
The results achieved at the Centre of Excellence in Learning and Motivation Research were presented at Finland's Academy of Science breakfast on 21 August.
Headed by Professor Lyytinen at the University of Jyvaskyla, the study compared 107 children with a dyslexic parent to a control group of children without a hereditary predisposition to dyslexia. The researchers followed the children from birth through school age.
"Half of the children whose parents had difficulties in reading and writing found learning to read more challenging than children in the control group. The atypical characteristics of these children's linguistic development indicated the risk at a very early age," says Lyytinen.
According to Lyytinen, the predictors of reading and writing difficulties are evident primarily in two contexts: a delayed ability to perceive and mentally process the subtleties of a person's voice, and a sluggishness in naming familiar, visually presented objects.
To read the entire article, go to:
www.dys-add.com/PreschoolPredictors.pdf
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Brain Research
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Reading and the Brain
This 30-minute video, hosted by Henry Winkler, who has his own struggles with reading, explores how brain scientists are working to solve the puzzle of why some children struggle to read and others don't. Startling new research shows the answer may lie in how a child's brain is wired from birth.
This program is the newest episode on Launching Young Readers, WETA's award-winning series of innovative half-hour programs about how children learn to read, why so many struggle, and what we can do to help.
To watch Reading and the Brain, FREE, go to:
www.readingrockets.org/shows/watch#brain
Dyslexia Begins When Wires Don't Meet
excerpt of an article by
Mark Roth, Pittsburg Post-Gazette
published on www.post-gazette.com
Dr. Just, a brain researcher at Carnegie Mellon University, and his colleagues, as well as brain imaging carried out at Georgetown University, Yale University and other centers, has proven that seeing letters in reverse or out of order is NOT the cause of dyslexia.
Using functional magnetic resonance imaging (fMRI), which measures blood flow to different parts of the brain, researchers now know that dyslexia involves a weakness in the part of the brain that decodes the sounds of written language.
That region sits above the left ear, at the junction of the brain's temporal and parietal lobes.
Researchers have also shown that the right kind of intensive instruction can rewire the brain and help overcome reading deficits. When Carnegie Mellon scanned the brains of youngsters who received a year of concentrated reading instruction, they showed 40 percent more activity in the word decoding areas of their brains, Dr. Just said.
A similar study at Yale showed that a year after receiving such instruction, boys and girls continued to show increased activity in both the word-decoding and word-forming areas of their brains.
A study at Georgetown University showed that intensive intervention also helps adults with dyslexia.
To read the entire article, go to:
www.dys-add.com/DyslexiaBegins.pdf
Slow Reading in Dyslexia Tied to Disorganized Brain Tracts
excerpt of an article
published December 5, 2007
in Science Daily
Dyslexia marked by poor reading fluency -- slow and choppy reading -- may be caused by disorganized, meandering tracts of nerve fibers in the brain, according to researchers at Children's Hospital Boston and Beth Israel Deaconess Medical Center.
The study, using the latest imaging methods, gives researchers a glimpse of what may go wrong in the structure of some dyslexic readers' brains, making it difficult to integrate the information needed for rapid, "automatic" reading.
To read the entire article, go to:
www.dys-add.com/SlowReadingScienceDaily.pdf
Overcoming Dyslexia: Timing of 'Connections' in Brain is Key
excerpt of an article
published September 10, 2007
in Science Daily
Using new software developed to investigate how the brains of dyslexic children are organized, University of Washington researchers have found that key areas for language and working memory involved in reading are connected differently in dyslexics than in children who are good readers and spellers.
However, once the children with dyslexia received an intense and specialized instructional program, their patterns of functional brain connectivity normalized and were similar to those of good readers when deciding if sounds went with groups of letters in words.
To read the entire article, go to:
www.dys-add.com/Timing.pdf
Dyslexic children use nearly five times the brain area
Excerpt of a press release
from the University of Washington
Released on November 30, 2005
Dyslexic children use nearly five times the brain area as normal children while performing a simple language task, according to a new study by an interdisciplinary team of University of Washington researchers. The study shows, for the first time, that there are chemical differences in the brain function of dyslexic and non-dyslexic children.
The research, published in the current issue of the American Journal of Neuroradiology, also provides new evidence that dyslexia is a brain-based disorder.
This study, part of a wider UW effort to understand the basis of dyslexia and develop treatments for it, was funded by the National Institutes of Children Health and Human Development, a branch of the National Institutes of Health.
To read the entire article, go to:
www.dys-add.com/UofWResearch-Lactate.pdf
Remediation rewires dyslexic brains, provides lasting results
excerpt of a study by Carnegie Mellon University
published August 13, 2008
on www.sciencedaily.com
A new Carnegie Mellon University brain imaging study of dyslexic students shows that the brain can permanently rewire itself and overcome reading deficits, if students are given 100 hours of intensive remedial instruction.
The study, published in the August issue of the journal Neuropsychologia, shows that the remedial instruction resulted in an increase in brain activity in several cortical regions associated with reading, and that gains became further solidified during the year following instruction.
"This study demonstrates how remedial instruction can use the plasticity of the human brain to gain an educational improvement," said neuroscientist Marcel Just, director of Carnegie Mellon's Center for Cognitive Brain Imaging (CCBI) and senior author of the study. "Focused instruction can help underperforming brain areas to increase their brain proficiency."
To read the rest of the article, go to:
www.dys-add.com/RemediationRewires.pdf
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Spelling
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Significant difficulty with spelling, when writing sentences and stories, is the most obvious warning sign of dyslexia. That's why spelling is mentioned in research-based definition of dyslexia used by the International Dyslexia Association and the National Institute of Child Health and Human Development (NICHD), which is:
Dyslexia is characterized by difficulties with accurate and / or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction.
Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.
Spelling Fact Sheet
produced by the International Dyslexia Association
posted on their website in 2008
www.InterDys.org
The International Dyslexia Association has recently released a 4-page fact sheet on Spelling, which states that people with dyslexia have "conspicuous problems" with spelling and writing. The fact sheet quotes the research and explains how spelling needs to be taught.
To download that Spelling Fact Sheet, go to:
www.dys-add.com/IDA-SpellingFactSheet.pdf
Spelling Gene
excerpt of an article by Kate Wighton
published October 25, 2008
on www.timesonline.co.uk
In the past, poor spelling was attributed to all manner of things, from bad schooling to a lack of moral fiber. But science is offering a new explanation. A difficulty with spelling could be rooted in your genes and in the way your brain is wired. These findings stem from research into the language disorder dyslexia, but they are proving important for the wider population.
Tony Monaco, a scientist at the Wellcome Centre Trust for Human Genetics, Oxford University, believes that our ability to spell lies partly in our DNA. In his study, his lab tracked the development of 6,000 children born in the early Nineties. Previous studies highlighted a particular gene that might affect reading ability, KIAA0319. We all carry it, but he found that 15 percent of the population have a slightly different version than normal.
According to Professor Monaco, the normal version of the gene helps to guide brain cells into the cortex when a child is developing in the womb. When the gene is different, however, it is unable to properly fulfill its function; brain cells get lost on the journey and end up in the wrong place. "This may disrupt the processing of information," he says.
To read the entire article, go to:
www.dys-add.com/SpellingGene.pdf
Spelling Changes the Brain
excerpt of an article entitled
Brain Images Show Individual Dyslexic Children Respond to Spelling Treatment
published February 15, 2007, on www.medicalnewstoday.com
Brain images of children with dyslexia taken before they received spelling instruction show that they have different patterns of neural activity than do good spellers when doing language tasks related to spelling. But after specialized treatment emphasizing the letters in words, they showed similar patterns of brain activity.
These findings are important because they show the human brain can change and normalize in response to spelling instruction, even in dyslexia, the most common learning disability.
To read the entire article, go to:
www.dys-add.com/SpellingBrainScan.pdf
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Genes
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Genetic Differences
excerpt of an article called
Dissecting Dyslexia
on the Reading Rockets website
Children who cannot read fluently or spell accurately are often thought to lack intelligence or motivation. But in most cases, they are neither stupid nor lazy. They have dyslexia, which makes it difficult for them to understand written language despite having a normal -- or higher than normal -- IQ.
Recent studies suggest that their reading difficulties are caused by identifiable genetic variations that create "faulty wiring" in certain areas of the brain.
Luckily, most of our brain development occurs after we are born, when we interact with our environment. This means that the right teaching techniques can actually re-train the brain, especially when used early.
To read the entire article, go to:
www.dys-add.com/DissectingDyslexia.pdf
From Genes to Behavior
excerpt of an article by Albert M. Galaburda et al called
From Genes to Behavior in Developmental Dyslexia
published in Nature Neuroscience, October 2006
This scholarly research article expands on the following:
All four genes thus far linked to dyslexia impact brain development. Comparable abnormalities induced in young rodent brains cause auditory deficits, underscoring the potential relevance of these brain changes to dyslexia.
Our perspective on dyslexia is that some of the brain changes cause phonological processing abnormalities as well as auditory processing abnormalities.
Thus, we propose a pathway between a genetic effect, developmental brain changes, and perceptual deficits associated with dyslexia.
To read the entire article, go to:
www.dys-add.com/4Genes-Galaburda06.pdf
Scientists tie two additional genes to dyslexia
Excerpt of an article
by Sandra Blakeslee
Published in the New York Times on November 2, 2005
One year after scientists discovered a gene whose flaw contributes to dyslexia, two more such genes have been identified.
The findings, described yesterday in Salt Lake City at a meeting of the American Society of Human Genetics, support the idea that many people deemed simply lazy or stupid, because of their severe reading problems, may instead have a genetic disorder that interfered with the wiring of their brains before birth.
To read the entire article, go to:
www.dys-add.com/Genes-2more.pdf
Dyslexia Susceptibility Gene
excerpt of an article in the American Journal of Psychiatry
published in December 2008
on www.ajp.psychiatryonline.org
Dyslexia (reading disability) is a complex trait determined in large part by genetic factors. Association studies and translocation breakpoint analyses have proposed several genes as susceptibility candidates at some of the quantitative trait loci linked to dyslexia: DYX1C1 on chromosome 15, KIAA0319 and DCDC2 on chromosome 6, ROBO1 on chromosome 3, and MRPL19 and C20RF3 on chromosome 2.
The results of this study both support the role of K1AA0319 in the development of dyslexia and and suggest that this gene influence reading ability in the general population. Moreover, the data implicate the three-SNP haplotype and its tagging SNP rs2143340 as genetic risk factors for poor reading performance.
This research article is extremely technical but is a "must read" for those who want to understand the latest in genetic research.
To read the entire article, go to:
www.dys-add.com/AmJrnlPsychiatryDec2008gene.pdf
Musical ability connected to dyslexia gene
excerpt of study published in Journal of Medical Genetics
published June 30, 2008
reported on www.sciam.com
A team of Finnish and American geneticists have found that, for some people at least, music is in their genes. In what the researchers called the first study of its kind, they found specific regions of chromosomes that were connected to musical ability.
The chromosomal regions that were found to be connected to music are known to be involved in the migration of neurons during development. And the study also found that the musical DNA overlapped with a region associated with dyslexia.
To read that research study, go to:
www.dys-add.com/MusicGeneandDyslexia.pdf
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