Chapter 7. Life-Span Development of the Brain and Behavior
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By Melissa Hogenboom Science reporter, BBC News Changes to specific cells in the retina could help diagnose and track the progression of Alzheimer's disease, scientists say. A team found genetically engineered mice with Alzheimer's lost thickness in this layer of eye cells. As the retina is a direct extension of the brain, they say the loss of retinal neurons could be related to the loss of brain cells in Alzheimer's. The findings were revealed at the US Society for Neuroscience conference. The team believes this work could one day lead to opticians being able to detect Alzheimer's in a regular eye check, if they had the right tools. Alterations in the same retinal cells could also help detect glaucoma - which causes blindness - and is now also viewed as a neurodegenerative disease similar to Alzheimer's, the researchers report. Scott Turner, director of the memory disorders programme at Georgetown University Medical Center, said: "The retina is an extension of the brain so it makes sense to see if the same pathologic processes found in an Alzheimer's brain are also found in the eye." Dr Turner and colleagues looked at the thickness of the retina in an area that had not previously been investigated. This included the inner nuclear layer and the retinal ganglion cell layer. They found that a loss of thickness occurred only in mice with Alzheimer's. The retinal ganglion cell layer had almost halved in size and the inner nuclear layer had decreased by more than a third. BBC © 2013
SAN DIEGO, CALIFORNIA—Why do teens—especially adolescent males—commit crimes more frequently than adults? One explanation may be that as a group, teenagers react more impulsively to threatening situations than do children or adults, likely because their brains have to work harder to reign in their behavior, a research team reported here yesterday at the Society for Neuroscience meeting. Whether it's driving too fast on a slick road or experimenting with drugs, teenagers have a reputation for courting danger that is often attributed to immaturity or poor decision-making. If immaturity or lack of judgment were the only problem, however, one would expect that children, whose brains are at an even earlier stage of development, would have an equal or greater penchant for risk-taking, says Kristina Caudle, a neuroscientist at the Weill Cornell Medical College in New York City who led the study. But younger children tend to be more cautious than teenagers, suggesting that there is something unique about adolescent brain development that lures them to danger, she says. It's hard to generalize about teenage impulsivity, because some adolescents clearly have more self-control than many adults, says principal investigator B. J. Casey, a neuroscientist. Still, a growing body of evidence suggests that, in general, teens specifically struggle to keep their cool in social situations, she says. Because many crimes committed during adolescence involve emotionally fraught social situations, such as conflict, Caudle and colleagues decided to test whether teens perform badly on a common impulsivity task when faced with social cues of threat. They recruited 83 people, ranging in age from 6 to 29, to perform a simple "Go/No-Go" task, in which they watched a series of faces making neutral or threatening facial expressions flicker past on a computer screen. Each time the participants saw a neutral face, they were instructed to hit a button. They were also told to hold back from pressing the button when they saw a threatening face. As the participants performed the task, the researchers monitored their brain activity with functional magnetic resonance imaging. © 2013 American Association for the Advancement of Science.
Babies born to women who exercised during pregnancy have enhanced brain development compared with babies born to moms who didn’t exercise while they were pregnant, a new Canadian study suggests. The babies of 10 women who did as little as 20 minutes of moderate exercise three times a week during pregnancy showed more advanced brain activity when they were tested at eight to 12 days old than the babies of eight women who did not exercise during pregnancy, reported University of Montreal researcher David Ellemberg and his colleagues at the Neuroscience 2013 conference in San Diego on Sunday. “We are optimistic that this will encourage women to change their health habits, given that the simple act of exercising during pregnancy could make a difference for their child's future,” Ellemberg said in a statement. The women in the study were randomly assigned to an exercise group or a sedentary group at the beginning of their second trimester. Those in the exercise group had to spend at least 20 minutes three times a week doing exercise intense enough to lead to at least a slight shortness of breath. After their babies were born, the researchers tested them by placing a cap of electrodes on the babies' heads and then playing novel sounds while they slept. They measured the electrical response of the babies' brains to see how well they could distinguish between different sounds. The researchers found that the babies in the exercise group produced signals associated with more mature brains. The researchers said they plan to test the children’s cognitive, motor and language development at age one to see if there are lasting effects. © CBC 2013
Keyword: Development of the Brain
Link ID: 18916 - Posted: 11.12.2013
Jessica Wright A new test of mouse intelligence closely mimics the types of assays used with people and detects a subtle learning deficit reminiscent of one seen in teenagers with autism, according to findings presented Saturday at the2013 Society for Neuroscience annual meeting in San Diego. Another behavioral test, also presented Saturday, uncovers an unexpected social deficit in an autism mouse model. The test in the first study could be used to screen for drugs that improve cognitive deficits associated with autism, says Jill Silverman, a postdoctoral associate in Jacqueline Crawley’s lab at the University of California, Davis MIND Institute. Silverman presented the work at a poster session. To measure learning in mice, researchers typically place them in a water maze, or see if they learn to anticipate an electric shock. “But you don’t shock people or put them in a pool to swim,” notes Silverman. Silverman instead trained the mice in a human activity: using a touchscreen. In the most basic form of the test, the mice see two graphic images (such as a plane and a spider) and learn that they get “yummy” strawberry milkshake if they touch the spider, Silverman says. (She says she uses milkshakes because the mice work hard for them, even if they aren’t hungry.) BTBR mice, which have many autism-like features, learn to go for the spider just as readily as control mice do. So Silverman made things much more complicated. The complex test follows the logic of transitive properties. For example, if John is taller than Anne and Anne is taller than Jane, we are able to infer that John is taller than Jane. © Copyright 2013 Simons Foundation
Sarah DeWeerdt Parts of the brain that process vision and control movements are poorly connected in children with autism, according to results presented Saturday at the 2013 Society for Neuroscience annual meeting in San Diego. In addition to the social deficits that are a core feature of autism, children with the disorder often have clumsy movements. Studies have also found that people with autism have trouble imitating others. The new study uncovers patterns of brain activity suggesting all three of these deficits may be related. The researchers used functional magnetic resonance imaging (fMRI) to measure resting-state activation — brain activity that occurs while individuals are resting quietly in the scanner — in 45 children with autism and 45 controls. Parts of the brain that tend to activate and deactivate together during this procedure are said to be functionally connected. The researchers zeroed in on two sets of brain structures involved in motor activity. One of them, the ventral motor component, includes parts of the cortex, the thalamus and lobule 6 of the cerebellum. They also focused on three areas of the brain involved in visual processing. The most interesting is a region at the back of the brain responsible for complex interpretation of visual information. © Copyright 2013 Simons Foundation
by Laura Sanders Neonatal intensive care units are crammed full of life-saving equipment and people. The technology that fills these bustling hubs is responsible for saving the lives of fragile young babies. That technology is also responsible for quite a bit of noise. In the NICU, monitors beep, incubators whir and nurses, doctors and family members talk. This racket isn’t just annoying: NICU noise often exceeds acceptable levels set by the American Academy of Pediatrics, a 2009 analysis found. To dampen the din, many hospitals are shifting away from open wards to private rooms for preemies. Sounds like a no-brainer, right? Fragile babies get their own sanctuaries where they can recover and grow in peace. But in a surprising twist, a new study finds that this peace and quiet may actually be bad for some babies. Well aware of the noise problem in the NICU ward, Roberta Pineda of Washington University School of Medicine in St. Louis and colleagues went into their study of 136 preterm babies expecting to see benefits in babies who stayed in private rooms. Instead, the researchers found the exact opposite. By the time they left the hospital, babies who stayed in private rooms had less mature brains than those who stayed in an open ward. And two years later, babies who had stayed in private rooms performed worse on language tests. The results were not what the team expected. “It was extremely surprising,” Pineda told me. The researchers believe that the noise abatement effort made things too quiet for these babies. As distressing data from Romanian orphanages highlights, babies need stimulation to thrive. Children who grew up essentially staring at white walls with little contact from caregivers develop serious brain and behavioral problems, heartbreaking results from the Bucharest Early Intervention Project show. Hearing language early in life, even before birth, might be a crucial step in learning to talk later. And babies tucked away in private rooms might be missing out on some good stimulation. © Society for Science & the Public 2000 - 2013
Kenneth S. Kosik Twenty years of research and more than US$1-billion worth of clinical trials have failed to yield an effective drug treatment for Alzheimer's disease. Most neuroscientists, clinicians and drug developers now agree that people at risk of the condition will probably need to receive medication before the onset of any cognitive symptoms. Yet a major stumbling block for early intervention is the absence of tools that can reveal the first expression of the insidious disease. So far, researchers have tended to focus on macroscopic changes associated with the disease, such as the build up of insoluble plaques of protein in certain areas of the brain, or on individual genes or molecular pathways that seem to be involved in disease progression. I contend that detecting the first disruptions to brain circuitry, and tracking the anatomical and physiological damage underlying the steady cognitive decline that is symptomatic of Alzheimer's, will require tools that operate at the 'mesoscopic' scale: techniques that probe the activity of thousands or millions of networked neurons. Although such tools are yet to be realized, several existing technologies indicate that they are within reach. Charted territory All the current approaches that are used to diagnose Alzheimer's are crude and unreliable. Take the classic biomarkers of the disease: a build up of plaques of the protein β-amyloid in a person's cerebral cortex, for instance, or elevated levels of the tau protein and dampened levels of β-amyloid in their cerebrospinal fluid. Although such markers are predictive of the disease, the interval between their appearance and the onset of cognitive problems is hugely variable, ranging from months to decades. © 2013 Nature Publishing Group
Helen Shen A mixture of excitement, hope and anxiety made for an electric atmosphere in the crowded hotel ballroom. On a Monday morning in early May, neuroscientists, physicists and engineers packed the room in Arlington, Virginia, to its 150-person capacity, while hundreds more followed by webcast. Only a month earlier, US President Barack Obama had unveiled the neuroscience equivalent of a Moon shot: a far-reaching programme that could rival Europe's 10-year, €1-billion (US$1.3-billion) Human Brain Project (see page 5). The US Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative would develop a host of tools to study brain activity, the president promised, and lead to huge breakthroughs in understanding the mind. But Obama's vague announcement on 2 April had left out key details, such as what the initiative's specific goals would be and how it would be implemented. So at their first opportunity — a workshop convened on 6 May by the National Science Foundation (NSF) and the Kavli Foundation of Oxnard, California — researchers from across the neuroscience spectrum swarmed to fill in the blanks and advocate for their favourite causes. The result was chaotic, acknowledges Van Wedeen, a neurobiologist at Harvard Medical School in Boston, Massachusetts, and one of the workshop's organizers. Everyone was afraid of being left out of 'the next big thing' in neuroscience — even though no one knew exactly what that might be. “The belief is we're ready for a leap forward,” says Wedeen. “Which leap, and in which direction, is still being debated.” © 2013 Nature Publishing Group
Ewen Callaway Children with autism make less eye contact than others of the same age, an indicator that is used to diagnose the developmental disorder after the age of two years. But a paper published today in Nature1 reports that infants as young as two months can display signs of this condition, the earliest detection of autism symptoms yet. If the small study can be replicated in a larger population, it might provide a way of diagnosing autism in infants so that therapies can begin early, says Warren Jones, research director at the Marcus Autism Center in Atlanta, Georgia. Jones and colleague Ami Klin studied 110 infants from birth — 59 of whom had an increased risk of being diagnosed with autism because they had a sibling with the disorder, and 51 of whom were at lower risk. One in every 88 children has an autism spectrum disorder (ASD), according to the most recent survey by the US Centers for Disease Control and Prevention in Atlanta. At ten regular intervals over the course of two years, the researchers in the new study showed infants video images of their carers and used eye-tracking equipment and software to track where the babies gazed. “Babies come into the world with a lot of predispositions towards making eye contact,” says Jones. “Young babies look more at the eyes than at any part of the face, and they look more at the face than at any part of the body.” Twelve children from the high-risk group were diagnosed with an ASD — all but two of them boys — and one male from the low-risk group was similarly diagnosed. Between two and six months of age, these children tended to look at eyes less and less over time. However, when the study began, these infants tended to gaze at eyes just as often as children who would not later develop autism. © 2013 Nature Publishing Group
By PAM BELLUCK In a study published Wednesday, researchers using eye-tracking technology found that children who were found to have autism at age 3 looked less at people’s eyes when they were babies than children who did not develop autism. But contrary to what the researchers expected, the difference was not apparent at birth. It emerged in the next few months and autism experts said that might suggest a window during which the progression toward autism can be halted or slowed. The study, published online in the journal Nature, found that infants who later developed autism began spending less time looking at people’s eyes between 2 and 6 months of age and paid less attention to eyes as they grew older. By contrast, babies who did not develop autism looked increasingly at people’s eyes until about 9 months old, and then kept their attention to eyes fairly constant into toddlerhood. “This paper is a major leap forward,” said Dr. Lonnie Zwaigenbaum, a pediatrician and autism researcher at the University of Alberta, who was not involved in the study. “Documenting that there’s a developmental difference between 2 and 6 months is a major, major finding.” The authors, Warren R. Jones and Ami Klin, both of the Marcus Autism Center and Emory University, also found that babies who showed the steepest decline in looking at people’s eyes over time developed the most severe autism. “Kids whose eye fixation falls off most rapidly are the ones who later on are the most socially disabled and show the most symptoms,” said Dr. Jones, director of research at the autism center. “These are the earliest known signs of social disability, and they are associated with outcome and with symptom severity. Our ultimate goal is to translate this discovery into a tool for early identification” of children with autism. Copyright 2013 The New York Times Company
Link ID: 18889 - Posted: 11.07.2013
Learning a musical instrument as a child gives the brain a boost that lasts long into adult life, say scientists. Adults who used to play an instrument, even if they have not done so in decades, have a faster brain response to speech sounds, research suggests. The more years of practice during childhood, the faster the brain response was, the small study found. The Journal of Neuroscience work looked at 44 people in their 50s, 60s and 70s. The volunteers listened to a synthesised speech syllable, "da", while researchers measured electrical activity in the region of the brain that processes sound information - the auditory brainstem. Despite none of the study participants having played an instrument in nearly 40 years, those who completed between four and 14 years of music training early in life had a faster response to the speech sound than those who had never been taught music. Lifelong skill Researcher Michael Kilgard, of Northwestern University, said: "Being a millisecond faster may not seem like much, but the brain is very sensitive to timing and a millisecond compounded over millions of neurons can make a real difference in the lives of older adults." As people grow older, they often experience changes in the brain that compromise hearing. For instance, the brains of older adults show a slower response to fast-changing sounds, which is important for interpreting speech. Musical training may help offset this, according to Dr Kilgard's study. BBC © 2013
by Catherine de Lange Speak more than one language? Bravo! It seems that being bilingual helps delay the onset of several forms of dementia. Previous studies of people with Alzheimer's disease in Canada showed that those who are fluent in two languages begin to exhibit symptoms four to five years later than people who are monolingual. Thomas Bak at the University of Edinburgh, UK, wanted to know whether this was truly down to language, or whether education or immigration status might be driving the delay, since most bilingual people living in Toronto, where the first studies were conducted, tended to come from an immigrant background. He also wondered whether people suffering from other forms of dementia might experience similar benefits. He teamed up with Suvarna Alladi, a neurologist working on memory disorders at Nizam's Institute of Medical Sciences (NIMSH) in Hyderabad, India. "In India, bilingualism is part of everyday life," says Bak. The team compared the age that dementia symptoms appeared in some 650 people who visited the NIMSH over six years. About half spoke at least two languages. This group's symptoms started on average four and a half years later than those in people who were monolingual. "Incredibly the number of years in delay of symptom onset they reported in the Indian sample is identical to our findings," says Ellen Bialystok, at Toronto's York University, who conducted the original Canadian studies. What's more, the same pattern appeared in three different types of dementia: Alzheimer's, frontotemporal and vascular. The results also held true for a group of people who were illiterate, suggesting that the benefits of being bilingual don't depend on education. © Copyright Reed Business Information Ltd.
by Anil Ananthaswamy THE first clinical trial aimed at boosting social skills in people with autism using magnetic brain stimulation has been completed – and the results are encouraging. "As a first clinical trial, this is an excellent start," says Lindsay Oberman of the Beth Israel Deaconess Medical Centre in Boston, who was not part of the study. People diagnosed with autism spectrum disorder often find social interactions difficult. Previous studies have shown that a region of the brain called the dorsomedial prefrontal cortex (dmPFC) is underactive in people with autism. "It's also the part of the brain linked with understanding others' thoughts, beliefs and intentions," says Peter Enticott of Monash University in Melbourne, Australia. Enticott and his colleagues wondered whether boosting the activity of the dmPFC using repetitive transcranial magnetic stimulation (rTMS), which involves delivering brief but strong magnetic pulses through the scalp, could help individuals with autism deal with social situations. So the team carried out a randomised, double-blind clinical trial – the first of its kind – involving 28 adults diagnosed with either high-functioning autism or Asperger's syndrome. Some participants received 15 minutes of rTMS for 10 days, while others had none, but experienced all other aspects, such as having coils placed on their heads and being subjected to the same sounds and vibrations. © Copyright Reed Business Information Ltd.
Link ID: 18863 - Posted: 11.02.2013
A new report released today by the Institute of Medicine (IOM) may help dispel some common misconceptions about sport-related concussions in youth—for example, that wearing helmets can prevent them. First and foremost, however, it highlights the large gaps in knowledge that make it difficult for parents, coaches, and physicians to navigate decisions about prevention and treatment. The report also suggests where federal research agencies should focus their attention. The study, by a 17-member committee assembled by the Washington, D.C.-based IOM, which advises the government on health issues, comes amid growing concern about sports-related brain injuries. Although much of the attention has focused on adult professional athletes playing American football, health professionals have highlighted the need to understand risks among young athletes as well. To help clarify matters, a number of agencies, including the Centers for Disease Control and Prevention (CDC), the Department of Defense, and the Department of Education, asked IOM to conduct its study. The most glaring obstacle to understanding youth concussion at this point is a lack of data, the report finds. Most published research on sports-related concussions has been conducted in adults, and “there’s little-to-no information about concussions in youth,” particularly for ages 5 to 21, says panel member Susan Margulies, a bioengineer at the University of Pennsylvania. It’s dangerous to assume that findings in adults can be mapped onto children, she says, because of the changes that occur during brain development. “It’s possible that the threshold for injury might be different across different age ranges.” © 2013 American Association for the Advancement of Science
By Ajai Raj Football has become notorious for the degeneration it causes in players' brains. Now a preliminary study of soccer players has found that frequently hitting the ball with the head may adversely affect brain structure and cognition. The study imaged the brains of 37 amateur soccer players, 21 to 44 years old, and found that players who reported “heading the ball” more frequently had microstructural changes in the white matter of their brains similar to those observed in patients with traumatic brain injury. These players also performed poorly on cognitive tests, compared with players who reported heading the ball less. The study, published online in June in Radiology, found evidence of a threshold—1,800 headings—above which the effects on memory begin to manifest. Neuroradiologist Michael Lipton of the Albert Einstein College of Medicine of Yeshiva University, who led the study, says the findings may indicate that heading causes mild concussions, even when players do not show symptoms. The results are noteworthy but far from conclusive, comments Jonathan French, a neuropsychologist in the Sports Medicine Concussion Program at the University of Pittsburgh Medical Center, who was not involved in the study. “The majority of soccer players who are concussed don't have any functional problems in everyday life,” he says. The structural changes detected in the study, he points out, are "so microscopic that we don't know what they actually mean” for long-term function. Lipton agrees more work is needed to determine the significance of the brain changes, but he hopes to call attention to the potential risk because soccer is the most popular sport in the world. © 2013 Scientific American
A mother's level of education has strong implications for a child's development. Northwestern University researchers show in a new study that low maternal education is linked to a noisier nervous system in children, which could affect their learning. "You really can think of it as static on your radio that then will get in the way of hearing the announcer’s voice," says Nina Kraus, senior author of the study and researcher at the Auditory Neuroscience Laboratory at Northwestern University. The study, published in the Journal of Neuroscience, is part of a larger initiative working with children in public high schools in inner-city Chicago. The adolescents are tracked from ninth to 12th grade. An additional group of children in the gang-reduction zones of Los Angeles are also being tracked. Kraus and colleagues are more broadly looking at how music experience, through classroom group-based musical experience, could offset certain negative effects of poverty. But first, they wanted to see what biological effects poverty may have on the adolescents' brain. In this particular study, 66 children - a small sample - in Chicago participated. Those whose mothers had a "lower education" tended to have not graduated from high school. Kraus's study did not directly track income of families, but most children in the study qualified for free lunch (to be eligible, a family of four must have income of about $29,000 or less). Researchers found "children from lower-SES (socioeconomic status) backgrounds are exposed to less complex and linguistically rich input in addition to hearing fewer words per hour from their caregivers," according to the study. © 2012 Cable News Network
Early childhood poverty has been linked to smaller brain size by U.S. researchers who are pointing to the importance of nurturing from caregivers as a protective factor. Children exposed to poverty tend to have poorer cognitive outcomes and school performance. To learn more about the biology of how, researchers started tracking the emotional and brain development of 145 preschoolers in metropolitan St. Louis for 10 years. Household poverty was measured by the income-to-needs ratio. Children were assessed each year for thee to six years before they received an MRI and questionnaires. A parent and child were also observed during a lab task that required the child (age four to seven) to wait for eight minutes before opening a brightly wrapped gift within arm's reach while the parent filled in questionnaires. "These study findings demonstrated that exposure to poverty during early childhood is associated with smaller white matter, cortical grey matter, and hippocampal and amygdala volumes," Dr. Joan Luby of the psychiatry department at Washington University School of Medicine in St. Louis and her co-authors concluded in Monday's issue of the journal JAMA Pediatrics. The findings were consistent with an earlier study by the same team that suggested supportive parenting also plays an important role in the development of the hippocampus in childhood independent of income. The brain's hippocampus is important for learning and memory and how we respond to stress. In the study, the effects of poverty on hippocampal volume was influenced by caregiving support or hospitality in the brain's light and right hemispheres and stressful life events on the left. Caregiver education was not a significant mediator. © CBC 2013
By David Dobbs If you want a look at a high-profile field dealing with a lot of humbling snags, peer into #ASHG2013, the Twitter hashtag for last week’s meeting of the American Society of Human Genetics, held in Boston. You will see successes, to be sure: Geneticists are sequencing and analyzing genomes ever faster and more precisely. In the last year alone, the field has quintupled the rate at which it identifies genes for rare diseases. These advances are leading to treatments and cures for obscure illnesses that doctors could do nothing about only a few years ago, as well as genetic tests that allow prospective parents to bear healthy children instead of suffering miscarriage after miscarriage. But many of the tweets—or any frank geneticist—will also tell you stories of struggle and confusion: The current list of cancer-risk genes, the detection of which leads some people to have “real organs removed,” likely contains many false positives, even as standard diagnostic sequencing techniques are missing many disease-causing mutations. There’s a real possibility that the “majority of cancer predisposition genes in databases are wrong.” And a sharp team of geneticists just last week cleanly dismantled a hyped study from last year that claimed to find a genetic signature of autism clear enough to diagnose the risk of it in unborn children. This sample reads like an abstract of the entire field of genetics. In researching a book about genetics over the past four years, I’ve found a field that stands in a bizarre but lovely state of confusion—taken aback, but eager to advance; balanced tenuously between wild ambition and a deep but troubling humility. In the 13 years since the sequencing of the first human genome, the field has solved puzzles that 14 years ago seemed hopeless. Yet geneticists with any historical memory hold a painful awareness that their field has fallen short of the glory that seemed close at hand when Francis Collins, Craig Venter, and Bill Clinton announced their apparent triumph in June 2000. © 2013 The Slate Group, LLC
Keyword: Genes & Behavior
Link ID: 18846 - Posted: 10.29.2013
By Amanda Mascarelli, When my son was in preschool, I did what many parents of excessively energetic and impulsive preschoolers have surely done: I worried whether his behavior might be a sign of attention-deficit hyperactivity disorder (ADHD). Then I sought input from two pediatricians and a family therapist. The experts thought that his behavior was developmentally normal but said it was still too early to tell for sure. They offered some tips on managing his behavior and creating more structure at home. One pediatrician worked with my son on self-calming techniques such as breathing deeply and pushing on pressure points in his hands. He also suggested an herbal supplement, Valerian Super Calm, for him to take with meals and advised us on dietary adjustments such as increasing my son’s intake of fatty acids. Studies have shown that a combination of omega-3 (found in foods such as walnuts, flaxseed and salmon) and omega-6 fatty acids (from food oils such as canola and flax) can reduce hyperactivity and other ADHD symptoms in some children. In the couple of years since trying these techniques, my son has outgrown most of those worrisome behaviors. I had just about written off the possibility of ADHD until a few weeks ago, when his kindergarten teacher mentioned that she was going to keep an eye on him for possible attention issues. Hearing that left me worried and heavy-hearted. Why is it still so hard to diagnose ADHD? And why is there so much emotional baggage associated with treating it? There are no firm numbers for the number of children with ADHD in the United States. The Centers for Disease Control and Prevention estimates that 9 percent of U.S. children ages 5 to 17 had received diagnoses of ADHD as of 2009. © 1996-2013 The Washington Post
By James Gallagher Health and science reporter, BBC News A clearer picture of what causes Alzheimer's disease is emerging after the largest ever analysis of patients' DNA. A massive international collaboration has now doubled the number of genes linked to the dementia to 21. The findings, published in the journal Nature Genetics, indicate a strong role for the immune system. Alzheimer's Research UK said the findings could "significantly enhance" understanding of the disease. The number of people developing Alzheimer's is growing around the world as people live longer. However, major questions around what causes the dementia, how brain cells die, how to treat it or even diagnose it remain unanswered. "It is really difficult to treat a disease when you do not understand what causes it," one of the lead researchers, Prof Julie Williams from Cardiff University, said. Detective work The genetic code, the instructions for building and running the body, was scoured for clues. A group - involving nearly three quarters of the world's Alzheimer's geneticists from 145 academic institutions - looked at the DNA of 17,000 patients and 37,000 healthy people. They found versions of 21 genes, or sets of instructions, which made it more likely that a person would develop Alzheimer's disease. They do not guarantee Alzheimer's will develop, but they do make the disease more likely. By looking at the genes' function in the body, it allows researchers to figure out the processes going wrong in Alzheimer's disease. BBC © 2013