Links for Keyword: Dyslexia
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
Bruce Bower For the first time, scientists have identified a gene that appears to influence the development of at least some cases of dyslexia. This learning disorder is characterized by difficulties in perceiving sounds within words, spelling and reading problems, and troubles with written and oral expression. It's estimated that dyslexia affects at least 1 in 25 people. Although scientists are investigating dyslexia's suspected neural roots (SN: 5/24/03, p. 324: http://www.sciencenews.org/20030524/fob4.asp), the condition's causes remain unknown. If confirmed in further studies, the new genetic finding represents a major step forward for dyslexia researchers. Until now, investigators have only been able to link dyslexia to alterations along stretches of DNA containing tens or hundreds of genes. The most prominent of these genetic segments are located on chromosomes 6 and 15. Copyright ©2003 Science Service.
For the 10 to 15 percent of school-aged children in the U.S. who suffer from dyslexia, the written word often feels like an insurmountable obstacle. But a spate of research is helping scientists get to the root of the condition and suggest new methods of treatment. Research published today in the journal Neurology suggests that some therapies can make a difference quickly. Scientists report that dyslexic children showed normal brain activation patterns during reading tests after just three weeks of specialized instruction. Elizabeth Aylward of the University of Washington and her colleagues tested 10 children who suffered from dyslexia and scored 30 percent below average on standardized reading tests despite having above average intelligence and 11 children classified as good readers. © 1996-2003 Scientific American, Inc.
Gene hint to human reading ability. HELEN PEARSON A Finnish family has given the first clear clue to a gene involved in dyslexia. Between 5 and 15% of people are dyslexic. They have problems reading, writing and spelling. Although scientists have suspected that genes are involved, they had not come up with a convincing candidate - until now. One gene is mutated in around 10% of Finnish dyslexics, compared with 2-3% in the rest of the population, Juha Kere of the University of Helsinki, Finland and his team found. "If you have the gene you become more susceptible, but you're not necessarily dyslexic," he says. © Nature News Service / Macmillan Magazines Ltd 2003
BY ROBYN SURIANO The Orlando Sentinel - Mariel Segovia changes from her stylish denim jacket and black jeans into drab, green hospital scrubs and climbs onto a table for a brain scan. The Neuroimaging machine is pulled into place, swallowing most of the 10-year-old's head like a giant helmet. The $1.8 million device is so sensitive that the metal buttons on Mariel's jeans would disrupt the machine. Any body movement - even blinking - is also bad for the machine. So Mariel is lying still with her hands clasped on her chest, eyes focused on a computerlike screen hanging above her. This is not a medical test, and Mariel is not a patient. The healthy fifth-grader with a sister, brother and a trampoline at her Texas home is helping research that could revolutionize the way reading is taught in America. © 2002, The Orlando Sentinel (Fla.).
Copyright © 2002 AP Online The Associated Press - Scientists have found new evidence linking the reading problem called dyslexia to glitches in a particular region of the brain. The evidence comes from brain scans of 70 dyslexic and 74 non-impaired children, ages 7 to 18. It follows a 1998 brain scan study that reported the link in adults. The new work, by including children as young as 7, shows the brain problem is present at the beginning of reading ability, said researcher Sally Shaywitz of Yale University. Copyright © 2001 Nando Media
Missile-tracking technology may spot symptoms of learning impairment. VIRGINIA GEWIN Eye-tracking glasses developed to reduce fighter pilots' workload by enabling their eyes to direct weapons could help to diagnose dyslexia. Qinetiq, part of the British government's former Defence Evaluation and Research Agency, has just received a grant to create child-size prototype glasses. Some scientists think that eye movements offer clues as to why dyslexics struggle to read and write. Dyslexia affects between five and ten per cent of the world's population. "Many of the problems are due to failure of the eyes to remain steady when they're trying to take in the visual form of words," says dyslexia researcher John Stein of the University of Oxford, who is working with Qinetiq. Until now, he says, "we've lacked a means of measuring eye movements accurately". © Nature News Service / Macmillan Magazines Ltd 2002
FORTUNE examines business leaders and artists who have gone beyond the limitations of dyslexia. By Betsy Morris Consider the following four dead-end kids. One was spanked by his teachers for bad grades and a poor attitude. He dropped out of school at 16. Another failed remedial English and came perilously close to flunking out of college. The third feared he'd never make it through school--and might not have without a tutor. The last finally learned to read in third grade, devouring Marvel comics, whose pictures provided clues to help him untangle the words. These four losers are, respectively, Richard Branson, Charles Schwab, John Chambers, and David Boies. Billionaire Branson developed one of Britain's top brands with Virgin Records and Virgin Atlantic Airways. Schwab virtually created the discount brokerage business. Chambers is CEO of Cisco. Boies is a celebrated trial attorney, best known as the guy who beat Microsoft. © Copyright 2002 Time Inc. All rights reserved.
A 10-minute screening test to identify pre-school children who might be dyslexic has been developed by language experts at University College London. The test will be used by children from the age of three and a half upwards, says Professor Heather van der Lely. But Dr John Rack of Dyslexia Action urged caution about the risk of "false alarms" from short screening tests. Dyslexia is a condition that can cause difficulty with reading, writing and spelling. The test has been developed by Professor van der Lely, who is director of the UCL Centre for Developmental Language Disorders and Cognitive Neuroscience. What makes this test different is that it can be carried out in only 10 minutes - and that it can be used before children are usually able to read, picking up any potential concerns before children have started full-time education. Professor van der Lely, speaking on BBC Radio 4's Today programme, said that the test, which asks a child to repeat sentences and re-tell a story, can help with early intervention. (C)BBC
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).
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."
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
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."
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
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.
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.
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.
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."
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 BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 15: Language and Our Divided Brain
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 BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 15: Language and Our Divided Brain; Chapter 2: 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 BP7e: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 5224 - Posted: 04.01.2004