The dyslexic brain struggles to read because even small distractions can throw it off, according to a new model of dyslexia emerging from a group of recent studies. The studies contradict an influential, 30-year-old theory that blamed dyslexia on a neural deficit in processing the fast sounds of language. Instead, the studies suggest that children with dyslexia have bad filters for irrelevant data. As a result, they struggle to form solid mental categories for identifying letters and word sounds. Such children may benefit from intensive training under "noisy" conditions to strengthen their mental templates, said University of Southern California neuroscientist Zhong-Lin Lu. Lu was a co-author on three studies, along with lead author and former USC graduate student Anne Sperling (now at the National Institute of Mental Health), USC psychologist Franklin Manis and University of Wisconsin, Madison psychologist Mark Seidenberg. The most recent study is due to be published later this month in Psychological Science. Confusion about dyslexia rivals the confusion of dyslexia. Many still think that to have dyslexia means to mix up your letters (one of many possible symptoms having to do with word recognition, directional ability and decoding of symbols).

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 9746 - Posted: 12.14.2006

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. The research is unique in that it looks at images of individual brains rather than the composite group images, or maps, that are typically produced to show which areas of the brain are activated when people are engaged in specific tasks. Being able to study how individual brains differ between good and poor spellers and how they normalize after receiving one of two treatments is an important advance, according to University of Washington neuroimaging scientist Todd Richards and neuropsychologist Virginia Berninger, who headed the research team. The new findings were published in the January issue of the journal Neurolinguistics. "Most people think dyslexia is a reading disorder, but it is also a spelling and writing problem," said Berninger, who directs the UW's Learning Disabilities Center. "Our results show that all dyslexics in the 9- to 12-year-old range have spelling problems and children who cannot spell cannot express their ideas in writing."

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 8507 - Posted: 02.09.2006

By SANDRA BLAKESLEE One year after scientists discovered a gene whose flaw contributes to dyslexia, two more such genes have now 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. "I am ecstatic about this research," said Dr. Albert M. Galaburda of Harvard Medical School, a leading authority on developmental disorders who was not involved in the latest discoveries. The findings, added to last year's, mean that for the first time, "we have a link between genes, brain development and a complex behavioral syndrome," Dr. Galaburda said. As many as a dozen genes are probably involved in the disorder, he said, with each playing a role in the necessary migration of neurons as the brain's circuitry develops. Researchers said a genetic test for dyslexia should be available within a year or less. Children in families that have a history of the disorder could then be tested, with a cheek swab, before they are exposed to reading instruction. If children carry a genetic risk, they could be placed in early intervention programs. Copyright 2005 The New York Times Company

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 8086 - Posted: 10.29.2005

Pediatric researchers at Yale School of Medicine have identified a gene on human chromosome 6 called DCDC2, which is linked to dyslexia, a reading disability affecting millions of children and adults. The researchers also found that a genetic alteration in DCDC2 leads to a disruption in the formation of brain circuits that make it possible to read. This genetic alteration is transmitted within families. "These promising results now have the potential to lead to improved diagnostic methods to identify dyslexia and deepens understanding of how the reading process works on a molecular level," said lead author Jeffrey R. Gruen, M.D., associate professor in the Pediatrics Department at Yale School of Medicine. The study will be published in a special issue of Proceedings of the National Academy of Sciences on October 28. Gruen and first author Haiying Meng will also present the findings that same day at the American Society of Human Genetics (ASHG) meeting in Salt Lake City, Utah. Gruen and co-authors used a statistical approach to study and compare specific DNA markers in 153 dyslexic families. "We now have strong statistical evidence that a large number of dyslexic cases--perhaps as many as 20 percent--are due to the DCDC2 gene," said Gruen. "The genetic alteration on this chromosome is a large deletion of a regulatory region. The gene itself is expressed in reading centers of the brain where it modulates migration of neurons. This very architecture of the brain circuitry is necessary for normal reading."

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 8083 - Posted: 10.29.2005

An education professor has cast doubt on the scientific validity of the term 'dyslexia', saying experts cannot agree on what it is or how to treat it. Writing in the Times Educational Supplement, Julian Elliott said it was largely an "emotional construct". The Durham University professor questions the scientific validity of the term 'dyslexia', saying diagnosis does not lead to particular treatment. The British Dyslexia Association says the claims are inflammatory. Professor Elliott, a psychologist, said his argument was based on "an exhaustive review of the research literature". After 30 years in the field, he said, he had little confidence in his ability to diagnose dyslexia. Professor Elliott told the BBC News website: "There is no consensus as to what it is and how to diagnose it. People describe all sorts of symptoms as dyslexia. And if you do diagnose it, it does not point to any intervention in particular. "It's one of those terms that is like the Cheshire Cat - if it does exist, we don't know what to do about it." He said, contrary to talk of 'miracle cures', there was no sound, widely-accepted body of scientific work that had shown that any particular teaching approach was more appropriate for 'dyslexic' children than for other poor readers". Dyslexia is defined by BBC health expert Dr Rob Hicks as "a congenital and developmental condition that causes neurological anomalies in the brain. (C)BBC

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 7843 - Posted: 09.03.2005

The dyslexic brain may have a general problem forming perceptual categories, including the templates for printed letters and speech sounds, say USC neuroscientists. This is reflected in a reduced ability to filter out visual "noise" that can obscure a pattern, the researchers suggest. Their novel hypothesis, published in the current issue of Nature Neuroscience, raises broader questions: Does the dyslexic brain's trouble with patterns and noise extend to other senses? Does poor filtering inhibit the formation of perceptual categories? Or is poor formation of categories the root cause of dyslexics' problem with noise? Dyslexia is the most common and perhaps least understood reading disability. Affecting millions of Americans, it has a history of uncertain explanations. An old, discredited, but persistent view is that dyslexics jumble their letters. In the 1980s, the subtler "magnocellular hypothesis" gained favor with some scientists. Named for a type of neuron, the hypothesis held that dyslexics struggle to process rapid visual signals. Language comprehension also requires rapid processing ability. The Nature Neuroscience study casts doubt on the magnocellular hypothesis. The lead author was Anne Sperling, a graduate of USC's neuroscience program whose Ph.D. thesis was based on the study. The research team, which included Zhong-Lin Lu and Franklin Manis, professors of psychology in the USC College of Letters, Arts and Sciences, and Mark Seidenberg of the University of Wisconsin, Madison, asked dyslexic and non- dyslexic children to identify patterns presented with and without visual noise.

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 7441 - Posted: 06.04.2005

MADISON - Addressing a persistent debate in the field of dyslexia research, scientists at the University of Wisconsin-Madison and the University of Southern California (USC) have disproved the popular theory that deficits in certain visual processes cause the spelling and reading woes commonly suffered by dyslexics. Rather, a more general problem in basic sensory perception may be at the root of the learning disorder, the scientists report today (May 29, 2005) in the journal Nature Neuroscience. The work suggests new ways to identify dyslexics and to assess the many unevaluated techniques teachers use to help dyslexics in the classroom. Misfiring neurons perhaps make it difficult for dyslexics to pick out relevant visual and auditory cues from the expanse of surrounding sounds and patterns, or "noise"; it is this inability that may bear heavily on how easily a child can read, says lead author Anne Sperling, who conducted the research as a USC graduate student, alongside co-author Mark Seidenberg, a UW-Madison psychology professor who left USC in 2001. "We really want to understand what is going on at the neurological level that's leading to reading problems," says Sperling. "[We think] that if a child has a hard time ignoring 'noise,' it could distort speech perception and complicate [the recognition] of sound segments, which is essential for learning how to read." A learning disorder with neurological underpinnings, dyslexia affects between 5 to 10 percent of children in the U.S. Sperling calls the condition a "spiraling problem" because poor reading interferes with many types of learning.

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 7414 - Posted: 05.31.2005

EVANSTON, Ill. --- Learning disabilities such as dyslexia are believed to affect nearly one in 10 children. To better study them, a Northwestern University research team has developed a data-driven conceptual framework that links two well-established scientific concepts. In doing so, they also have developed a non-invasive diagnostic tool called BioMAP that can quickly identify children with learning disabilities. Scientists have long recognized that children who can best process various aspects of the sounds of language are more likely to read earlier and develop into better readers and writers than those who cannot. After a decade of research, Northwestern Professor Nina Kraus and her colleagues have discovered a subset of learning disabilities that results from a dysfunction in the way the brainstem encodes certain basic sounds of speech. In an article in the April "Trends in Neurosciences," Kraus, who is Hugh Knowles Professor of Communication Sciences and Neurobiology, and senior research analyst Trent Nicol for the first time ever have linked the source-filter model of acoustics with the cerebral cortex's "what" and "where" pathways via the auditory brainstem.

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 7141 - Posted: 04.05.2005

A gene which is likely to be one of the causes of dyslexia in children has been discovered by researchers at Cardiff University. They believe the major finding will give researchers a better understanding of what causes the brain disorder which disrupts reading and writing skills. It is now hoped that follow-up research will also lead to the discovery of treatments which could help children susceptible to dyslexia. The discovery was made by a team from the Department of Psychological Medicine, Wales College of Medicine. They carried out analysis of 300 families from Wales and the West of England where at least one child suffered from the disorder. The research team led by Professor Julie Williams and Professor Michael O'Donovan will now continue their study in order to discover more about the gene called "KIAA0319". The research will focus on discovering exactly how the gene works within the brain to disrupt reading and writing skills. Professor Williams said: "This is a major breakthrough and the first study to identify one gene which contributes to susceptibility to the common form of dyslexia. We would like to thank all the parents and children who took part in the study and would extend a call to new volunteers to take part in this important research."

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 6971 - Posted: 03.04.2005

EVANSTON, Ill. --- A Northwestern University study is the first to suggest that delayed brain development and its interaction with puberty may be key factors contributing to language-based learning disabilities such as dyslexia. The article will appear in the online edition of the Proceedings of the National Academy of Sciences (PNAS) the week of June 21. In "Learning Problems, Delayed Development and Puberty," co-authors Beverly A. Wright and Steven G. Zecker provide a new and overarching developmental hypothesis that could change the way that these disabilities, that affect one out of 12 children with normal intelligence, are studied, understood and treated. The authors are associate professors of communication sciences and disorders at Northwestern. "Approaching learning disabilities from the perspective of brain development could potentially unite many seemingly disparate deficits observed in adults with learning problems -- from evidence that their white brain matter is abnormally distributed to findings that they have difficulty distinguishing and manipulating language sounds," said Wright. The idea of brain delay also could help explain anecdotal evidence that learning disabled children toilet train late, have difficulty learning to ride a bicycle, talk later and generally appear less developmentally mature than their unaffected counterparts.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 15: Language and Lateralization
Link ID: 5685 - Posted: 06.22.2004

A brain imaging study has shown that, after they overcome their reading disability, the brains of formerly poor readers begin to function like the brains of good readers, showing increased activity in a part of the brain that recognizes words. The study appears in the May 1 Biological Psychiatry and was funded by the National Institute of Child Health and Human Development (NICHD), one of the National Institutes of Health. "These images show that effective reading instruction not only improves reading ability, but actually changes the brain's functioning so that it can perform reading tasks more efficiently," said Duane Alexander, M.D., Director of the NICHD. The research team was led by Bennett Shaywitz, M.D., and Sally Shaywitz, M.D, of Yale University, in New Haven, Connecticut. Other authors of the study were from Syracuse University, in Syracuse, New York; Vanderbilt University, in Nashville, Tennessee; and the NICHD. According to Dr. Sally Shaywitz, the results show that "Teaching matters and good teaching can change the brain in a way that has the potential to benefit struggling readers."

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 5320 - Posted: 04.20.2004

Men who smoke cannabis could be damaging their fertility, research carried out by Queen's University Belfast has suggested. The study by the university's Reproductive Medicine Research Group examined the direct effects on sperm function of THC, the active ingredient in cannabis. The group found that THC made sperm less likely to reach the egg to fertilise it. They also discovered that the presence of cannabis impaired another crucial function of sperm - the ability to digest the egg's protective coat with enzymes to aid its penetration. The government reclassified cannabis to a class C drug in January, putting it on a par with tranquilisers. Dr Sheena Lewis, from the university's Department of Obstetrics and Gynaecology, said on Wednesday that the recent reclassification of cannabis made research on its effects more important. "The need to determine its effects on male fertility is even greater, so that men can make an informed choice about smoking the drug based on its risks to their health," she said. (C)BBC

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 5224 - Posted: 04.01.2004

Even though there is evidence that dyslexia has a genetic basis, researchers will report new findings today (Feb. 12) that show children afflicted with the learning disability are not doomed to a life of reading difficulties. The brains of dyslexic children can be "jump-started" with a three-week-long instructional intervention to help them use the same brain areas as normal readers, leading to better reading ability. This intervention was developed at the University of Washington by Virginia Berninger. She and Elizabeth Aylward, both of the UW's multidisciplinary Learning Disabilities Center, will discuss their findings at a press briefing during the annual meeting of the American Association for the Advancement of Science in Seattle. Also participating in the briefing will be Dr. Wendy Raskind, UW professor of medicine, who will talk about genetic influences on dyslexia. "Most people think words are just words, but the human brain uses three neural circuits to code words in three forms, not just their meaning," said Berninger, a professor of educational psychology and director of the center.

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 4962 - Posted: 02.13.2004

By JOHN LANGONE Overcoming Dyslexia," by Dr. Sally Shaywitz. Knopf, $25.95. Early in this book about a disorder that may afflict one child in every five in America, the author dispels two widely held beliefs: that children with dyslexia are prone to seeing letters or words backward, and that the problem is linked to intelligence. "The problem is a linguistic one, not a visual one," writes Dr. Shaywitz, a professor of pediatrics at Yale. Dyslexia represents a difficulty with reading, she says, not with thinking skills, one that "does not reflect an overall defect in language," but rather a weakness in a part of the language system. Copyright 2003 The New York Times Company

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 4662 - Posted: 12.09.2003

Dyslexia may be caused by a fault in a single gene, scientists have suggested. Researchers in Finland say their finding may explain why the condition seems to run in families. Dyslexia affects about one in 10 people. It is the most common learning disorder in children. Many find it difficult to recognise and read words. Writing in the Proceedings of the National Academy of Sciences, scientists said a flaw in a gene called DYXC1 may cause the condition. Previous studies have suggested that people with dyslexia process information in a different area of the brain than the average person does, even though they are often of average or above-average intelligence. Other studies have suggested they use the right side of the brain for reading instead of the left side, which is better set up for processing words. (C) BBC

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 4172 - Posted: 08.27.2003

By BONNIE ROTHMAN MORRIS Dyslexia appears to be caused by two distinct types of brain problems, a new study has found. The researchers, from Yale, used scanning devices to examine the brains of 43 young adults with known reading disabilities while they performed reading tasks. Another group of 27 good readers were also studied. All the subjects had been tracked for reading ability since elementary school. Copyright 2003 The New York Times Company

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 4008 - Posted: 07.08.2003

by Matthew Dolbey, News Writer Stanford University researchers have recently discovered hope for people with dyslexia. The researchers reported that an intensive eight-week learning program helped remedy reading problems among 20 dyslexic children between the ages of eight and 12. Elise Temple, lead writer of the study and assistant professor at Cornell University, said proper training designed to help children understand rapid language sounds is pinnacle to helping people overcome dyslexia. "The most important finding of the study is that brain dysfunction in dyslexia, which has been shown [to occur] in other studies, can actually be changed and made better to a large degree with a training program that is dealing with their behavior and their reading," Temple said.

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 3512 - Posted: 03.05.2003

For the first time, researchers have shown that the brains of dyslexic children can be rewired - after undergoing intensive remediation training - to function more like those found in normal readers. The training program, which is designed to help dyslexics understand rapidly changing sounds that are the building blocks of language, helped the participants become better readers after just eight weeks. The findings were released Monday in ``Neural deficits in children with dyslexia ameliorated by behavioral remediation: Evidence from functional MRI,`` published by the Proceedings of the National Academy of Sciences Early Edition.

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 3472 - Posted: 02.25.2003

Flashing lights are being used in a computer programme designed to help dyslexics improve their reading and writing skills. The makers say trials have shown a dramatic improvement in both adults and children with dyslexia. They claim children who went through the six-week programme advanced their reading age by 11 months. Under the programme, a person's heart is monitored and they are shown flashing lights and colours. The makers of the technology - called Brightstar - say watching the lights trains structures in the brain to work more efficiently and so helps word recognition. The company behind Brightstar is Advanced Learning Science. Chief Executive Jim Hinds says the results of trials have been very impressive. (C) BBC

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 3254 - Posted: 01.03.2003

By LINDA VILLAROSA Jillian Polis, a second-year medical student at the Weill Medical College of Cornell University, admits that she had little if any experience with substance abuse. Raised in a suburb of Denver, she learned about drugs from popular culture. "I thought the only people who got addicted were those who were wealthy with nothing to do or the urban poor," said Ms. Polis, 23. "I got those images from movies like `Traffic' since there was little or no addiction that I knew of growing up.' " Jonathan Austrian, Ms. Polis's classmate at Cornell, said that he thought people used drugs simply to have a good time, and that he didn't know anyone who had been addicted. Copyright 2002 The New York Times Company

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 3230 - Posted: 12.24.2002