Researchers explore links between learning disorders in children

New interdisciplinary research from Western University has uncovered fundamental links among three major learning difficulties in some school-age children.

Although many children have specific problems with dyslexia, specific language impairment and dyscalculia, this study is the first to show a significant portion of these children have overlapping deficits.

Importantly, the research team has also devised a 10-minute screening test that could be administered broadly in primary schools to identify children at risk for the different disorders.

The collaborative project includes findings from four researchers at Western's Brain and Mind Institute (BMI) and the Faculty of Health Sciences that independently specialize in the three key developmental disorders.

Dyslexia is a deficit in the development of reading while specific language impairment is a disorder related to poor development of spoken language skills. Dyscalculia is a severe difficulty in making mathematical calculations.

Past research in these disorders has focused on each of these as single impairments, despite the widespread recognition that they commonly overlap.

For a study published in the journal PLOS ONE, Lisa Archibald and Janis Oram Cardy from the Faculty of Health Sciences' School of Communication Sciences and Disorders and Marc Joanisse and Daniel Ansari from BMI collaborated across disciplines and examined – for the first time ever – the co-occurrence of difficulties in reading, spoken language, and mathematical calculations in a large sample of school-age children.

In the study, researchers tested learning profiles of a large sample of school children aged 4 to 10-years old in the region of London, Ontario.

The research team found that although some of the children showed specific deficits in reading, spoken language, or math, a significant number of children exhibited a mixed profile of a reading plus a math deficit, or an even wider-ranging weakness spanning math, reading, and spoken language.

"This is the first time researchers have looked at possible learning difficulties in different areas in a large sample of the same kids," says Archibald, the PLOS One paper's lead author.

"It's an important first step in trying to understand the large variability that is commonly reported for groups with learning disabilities."

The study has also uncovered some essential hints as to why different learning patterns might occur in different children.

For instance, children who showed weaknesses on all three types of abilities also scored very low on a working memory assessment.

NB: Working memory is the ability to hold multiple pieces of information in mind and perform simple operations on them, such as repeating a sequence of digits in the reverse order in which they were presented. 

According to the findings, such children may require a more targeted approach to remediation, due to the complex nature of their difficulties.

Children who have more specific deficits did not show the same difficulty with working memory and would require quite different interventions.

"Educators face significant challenges in identifying learning problems in children. With additional testing, we hope that a new tool that we have developed will someday provide educators with a quick and effective method for identifying which children need extra help, but also a way to develop more individualized remediation programs," says Joanisse.

More information: Original Article: Archibald LMD, Oram Cardy J, Joanisse MF, Ansari D (2013) Language, Reading, and Math Learning Profiles in an Epidemiological Sample of School Age Children. PLoS ONE 8(10): e77463. DOI: 10.1371/journal.pone.0077463

FASD: Association found between poor academic achievement and maternal drinking

Education records from the WA Literacy and Numeracy Assessment statewide testing program were compared with maternal alcohol consumption data. Credit: iStock

Researchers from WA and the UK have linked heavy drinking and binge drinking, even occasionally during pregnancy, to children's academic achievement in reading, writing and spelling; and this impact is related to the trimester in which the exposure occurred.

These results lend further support to other international studies which have found prenatal alcohol exposure increases the risk of a range of neurodevelopmental disorders, including Fetal Alcohol Spectrum Disorder (FASD).

Lead author Colleen O'Leary, from Curtin's Centre for Population Health Research, says this study is a first.

"This is the first population-based study that utilises linked cohort and state-wide education test data to examine the effect of prenatal alcohol exposure on educational achievement," Dr O'Leary says.

The cohort of 4056 children aged 8-9 years-old were from the Randomly Ascertained Sample of Children born in Australia's Largest State study; a 10 per cent random sample of infants born in WA between 1995 and 1997.

FASD Indications

Information about maternal alcohol consumption was catergorised into dosage and pattern; low (1-2 standard drinks on occasion, less than 7 per week), moderate (3-4 standard drinks on occasion, 7 per week), binge drinking (more than 50g per occasion), and heavy drinking (more than 7 standard drinks per week).

They then matched this data with education records from the WA Literacy and Numeracy Assessment statewide testing program, and also examined absenteeism at these tests.

Resulting learning problems varied depending on the dose, timing, and drinking pattern of the prenatal alcohol exposure.

"Children exposed to heavy prenatal alcohol exposure during the first trimester were over twice as likely as comparison children to not achieve the reading benchmark," Dr O'Leary says.

"Prenatal exposure to occasional binge drinking in late pregnancy [second and/or third trimester] increased the risk of not achieving the benchmark for writing.

"Children of mothers binge drinking occasionally or drinking heavily at any stage during pregnancy were more likely to have been absent for the spelling test."

Dr O'Leary says results are particularly pertinent given the high rate of pregnancies reported to be unplanned – around 50 per cent – and thus associated risk of unintentional prenatal alcohol exposure.

While low or moderate levels of prenatal alcohol exposure was not associated with academic underachievement, Dr O'Leary stresses that other studies have demonstrated adverse offspring effects, even at very low doses.

As such, "we cannot conclusively state that any amount of alcohol is 'safe'."

She recommends exploring the impact of whether supportive family and school systems can improve academic achievement of children exposed prenatally to alcohol.

More information: www.ncbi.nlm.nih.gov/pubmed/23837182

More links seen between autism, ADHD

Kids with attention-deficit/hyperactivity disorder (ADHD) are 20 times more likely to exhibit some traits of autism than children without ADHD, according to a new study.

Joseph Biederman

One of every five ADHD kids in the study exhibited signs of autism such as slow language development, difficulty interacting with others and problems with emotional control, said study co-author Dr. Joseph Biederman, director of the pediatric psycho-pharmacology unit at Massachusetts General Hospital.

These kids also showed problems with "executive function," or the ability to plan, organize and conceptualize future action, said Biederman, a professor of psychiatry at Harvard Medical School.

Fewer than 1 percent of kids in the non-ADHD comparison group exhibited any traits linked to autism, according to the study appearing in the September issue of Pediatrics.

"These children are not having the full diagnosis of autism, but they have symptoms of autism," Biederman said.

"It may be important to screen children with ADHD for autistic traits because they may need more support, particularly in the educational and interpersonal domains."

Alice Mao

Previous studies of children with autism have found that many also have severe ADHD symptoms. This is one of the first studies to turn the tables and see if the reverse is true, said Dr. Alice Mao, an associate professor of psychiatry at Baylor College of Medicine. She was not involved with the study.

"Generally, autistic kids with ADHD are challenging to treat because they don't respond well to ADHD medications," Mao said. "You have to treat the autism symptoms and then treat the ADHD.

The conclusion would be that perhaps we should screen these ADHD kids who are not doing well on traditional ADHD treatments to see if they have comorbid autism traits."

The study included 242 kids aged 6 to 18 with ADHD as well as a 227-member "control" group of kids without ADHD.

The children were drawn from an existing large-scale sample pool that excluded any kids who had been diagnosed with autism.

The children and their parents filled out a series of questionnaires to grade their behaviour and compare it to generally accepted definitions of autistic traits.

The researchers found that 18 percent of kids with ADHD exhibited some behaviors that are common in autism, compared with 0.87 percent of kids from the control group.

The ADHD children with autistic traits had many more social problems than typical ADHD children.

They were more likely to fight with and be rejected by other kids, and displayed more school behaviour problems, more difficulties using their spare time and more friction with their siblings, the study authors noted.

The children with both ADHD and autistic traits also tended to more frequently suffer additional psychiatric and learning disorders than either kids with only ADHD or children in the control group.

"Those with autism traits have greater severity of symptoms and dysfunction," Mao said.

"Certainly it would be useful to screen kids with ADHD who have autism traits to see which kids may need more help socially, as well as to make sure they don't have lower intellectual functioning."

"You may be able to give other treatments that would be helpful in terms of improving their functioning."

These findings, along with previous research, point to the strong possibility that ADHD and autism share some genetic link, study author Biederman said.

"The genetic markers for ADHD have also been associated with autism," he said.

"These autistic traits may be present in other conditions as well. I am quite convinced that these traits may be present in children with mood and anxiety disorders."

Allergies among US children increase between 1997 and 2011

For U.S. children aged younger than 18 years, the prevalence of allergies increased from 1997 to 2011, with age, race/ethnicity, and income all affecting the prevalence, according to a May data brief issued by the U.S. Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS).

Kristen D. Jackson, M.P.H., and colleagues from the NCHS in Hyattsville, Md., reviewed data from the National Health Interview Surveys from 1997 to 1999 and from 2009 to 2011 to examine the prevalence of food and skin allergies in U.S. children younger than age 18 years.

According to the report, from 1997 to 2011 there was an increase in the prevalence of food and skin allergies among U.S. children.

The prevalence of skin allergies decreased, while respiratory allergies increased with increasing age.

The prevalence of food, skin, and respiratory allergies was lower among Hispanic children than among other races or ethnicities.

Compared with non-Hispanic white children, non-Hispanic black children were less likely to have respiratory allergies and more likely to have skin allergies.

The prevalence of food and respiratory allergies increased with income level, with children with family income equivalent to 200 percent or more of the poverty level experiencing the highest prevalence of allergy.

"Among children under age 18 years in the United States, the prevalence of food and skin allergies increased from 1997-1999 to 2009-2011," the authors write.

More information: More Information

Dyslexia: A New Synergy Between Education and Cognitive Neuroscience

Abstract 
Reading is essential in modern societies, but many children have dyslexia, a difficulty in learning to read.

Dyslexia often arises from impaired phonological awareness, the auditory analysis of spoken language that relates the sounds of language to print.

Behavioural remediation, especially at a young age, is effective for many, but not all, children.

Neuroimaging in children with dyslexia has revealed reduced engagement of the left temporo-parietal cortex for phonological processing of print, altered white-matter connectivity, and functional plasticity associated with effective intervention.

Behavioural and brain measures identify infants and young children at risk for dyslexia, and preventive intervention is often effective.

A combination of evidence-based teaching practices and cognitive neuroscience measures could prevent dyslexia from occurring in the majority of children who would otherwise develop dyslexia.

Full Text

Depression Stems from Miscommunication Between Brain Cells; Study Challenges Role of Serotonin in Depression

A new study from the University of Maryland School of Medicine suggests that depression results from a disturbance in the ability of brain cells to communicate with each other. 

Credit: © Artur Golbert / Fotolia

A new study from the University of Maryland School of Medicine suggests that depression results from a disturbance in the ability of brain cells to communicate with each other.

The study indicates a major shift in our understanding of how depression is caused and how it should be treated. Instead of focusing on the levels of hormone-like chemicals in the brain, such as serotonin, the scientists found that the transmission of excitatory signals between cells becomes abnormal in depression.

Scott M. Thompson

The research, by senior author Scott M. Thompson, Ph.D., Professor and Interim Chair of the Department of Physiology at the University of Maryland School of Medicine, was published online in the March 17 issue of Nature Neuroscience.

According to the Centers for Disease Control and Prevention, between 2005 and 2008, approximately one in 10 Americans were treated for depression, with women more than twice as likely as men to become depressed.

The most common antidepressant medications, such as Prozac (Fluoxetine), Zoloft (Setraline) and Celexa (Citalopram), work by preventing brain cells from absorbing serotonin, resulting in an increase in its concentration in the brain.

Unfortunately, these medications are effective in only about half of patients. Because elevation of serotonin makes some depressed patients feel better, it has been thought for over 50 years that the cause of depression must therefore be an insufficient level of serotonin.

The new University of Maryland study challenges that long-standing explanation.

"Dr. Thompson's groundbreaking research could alter the field of psychiatric medicine, changing how we understand the crippling public health problem of depression and other mental illness," says E. Albert Reece, M.D., Ph.D., M.B.A., Vice President for Medical Affairs at the University of Maryland and John Z. and Akiko K. Bowers Distinguished Professor and Dean at the University of Maryland School of Medicine.

"This is the type of cutting-edge science that we strive toward at the University of Maryland, where discoveries made in the laboratory can impact the clinical practice of medicine."

Depression affects more than a quarter of all U.S. adults at some point in their lives, and the World Health Organization (WHO) predicts that by 2020 it will be the second leading cause of disability worldwide.

Depression is also the leading risk factor for suicide, which causes twice as many deaths as murder, and is the third leading cause of death for 15-24 year olds.

The first major finding of the study was the discovery that serotonin has a previously unknown ability to strengthen the communication between brain cells.

"Like speaking louder to your companion at a noisy cocktail party, serotonin amplifies excitatory interactions in brain regions important for emotional and cognitive function and apparently helps to make sure that crucial conversations between neurons get heard," says Dr. Thompson.

"Then we asked, does this action of serotonin play any role in the therapeutic action of drugs like Prozac?"

To understand what might be wrong in the brains of patients with depression and how elevating serotonin might relieve their symptoms, the study team examined the brains of rats and mice that had been repeatedly exposed to various mildly stressful conditions, comparable to the types of psychological stressors that can trigger depression in people.

The researchers could tell that their animals became depressed because they lost their preference for things that are normally pleasurable.

For example, normal animals given a choice of drinking plain water or sugar water strongly prefer the sugary solution. Study animals exposed to repeated stress, however, lost their preference for the sugar water, indicating that they no longer found it rewarding.

This depression-like behaviour strongly mimics one hallmark of human depression, called anhedonia, in which patients no longer feel rewarded by the pleasures of a nice meal or a good movie, the love of their friends and family, and countless other daily interactions.

A comparison of the activity of the animals' brain cells in normal and stressed rats revealed that stress had no effect on the levels of serotonin in the 'depressed' brains.

Instead, it was the excitatory connections that responded to serotonin in strikingly different manner. These changes could be reversed by treating the stressed animals with antidepressants until their normal behaviour was restored.

"In the depressed brain, serotonin appears to be trying hard to amplify that cocktail party conversation, but the message still doesn't get through," says Dr. Thompson.

Using specially engineered mice created by collaborators at Johns Hopkins University School of Medicine, the study also revealed that the ability of serotonin to strengthen excitatory connections was required for drugs like antidepressants to work.

Sustained enhancement of communication between brain cells is considered one of the major processes underlying memory and learning.

The team's observations that excitatory brain cell function is altered in models of depression could explain why people with depression often have difficulty concentrating, remembering details, or making decisions.

Additionally, the findings suggest that the search for new and better antidepressant compounds should be shifted from drugs that elevate serotonin to drugs that strengthen excitatory connections.

"Although more work is needed, we believe that a malfunction of excitatory connections is fundamental to the origins of depression and that restoring normal communication in the brain, something that serotonin apparently does in successfully treated patients, is critical to relieving the symptoms of this devastating disease," Dr. Thompson explains.

The above story is reprinted from materials provided by University of Maryland Medical Center.

Understanding the Co-morbidity Between Dyslexia and Attention-Deficit Hyperactivity Disorder

Dyslexia and attention-deficit hyperactivity disorder (ADHD) are 2 of the most prevalent complex neurodevelopmental disorders of childhood, each affecting approximately 5% of the population in the United States.

These disorders are also each co-morbid with speech sound disorder and language impairment.

Understanding the nature of the comorbidity among these disorders could lead to advances in developmental theory, a deeper understanding of the genetic and brain mechanisms that cause disability, a more refined diagnostic classification scheme, and new treatments and interventions for children with these disorders.

As part of this special issue of Topics in Language Disorders, this review focuses on the comorbidity between dyslexia and ADHD.

It provides a review of the known etiological mechanisms that underlie each disorder. It describes the reconceptualization of these disorders using a multiple deficit model and provides a synopsis of recent studies that illustrate a cohesive approach to investigating the causes of comorbidity.

Future directions are discussed in the context of expanding these approaches to the co-morbidity among all 4 disorders.  

Read the full paper here

Orthography: the relationship between written symbols and sounds

In our previous 2 blogs we discussed briefly the sounds of letters and the sounds found inside words; 'Print Awareness' and 'Phonics and Phonemics'.

Taking this a step forward, we would like to introduce you to another term that is often used in describing language and one that has a big part to play in the detection of Dyslexia and the difficulties a child may have in learning to read and spell in a specific language; Orthography.

Orthography

Orthographies are writing systems, the relationship between the words we speak and how we write that down. Conversely, it is how we interpret and speak the words and letters that we see written on a page.

Orthography in Languages

It may surprise you to learn that the orthography of some languages are easier to interpret and learn than others. The complexity of a language's orthography, or writing system, can be a significant contributing factor to the difficulties experienced by readers who suffer from Dyslexia.

Symbols in Language

Languages such as Chinese have very simple orthographies because it has a pictorial languagee. Their written language is based on symbols that represent a picture of the word. Dyslexia is unknown in China.

The difference in the complexity of language and it's symbols versus sound interpretation is best described as the depth of the Orthography.

Shallow orthographies
Shallow Orthographies have a more straightforward, one-to-one relationship between sounds (graphemes) and letters (phonemes), and the spelling of words is very consistent. Italian and Finnish, which are examples of shallow orthographies and consequently, children and new readers, have very little trouble learning to decode words and match them to their sounds.

As a result, children who wish to learn to read in those languages, do so relatively quickly and with greater ease. Most readers who suffer from Dyslexia and are learning to read in a shallow orthography, learn to decode words with relative ease. Unfortunately, they can experience more difficulty with reading fluency and comprehension.

The hallmark symptom of dyslexia in a shallow orthography is the speed of rapid automatised naming (RAN - the speed of recalling and naming an object, word or letter once it is recognised).

Deep Orthographies
Unfortunately, one of the languages considered to be 'deep' is English, as well as Arabic, for example. They do not have a one-to-one correspondence between sounds (phonemes) and the letters (graphemes) that are intended to represent those sounds. As a result, children learn to read more slowly and with the potential for introducing more difficulties.

Overcoming this difficulty
Research has shown that the symptoms of Dyslexia in a deep orthography are a deficit in phonological awareness and difficulty in reading at the word level. For these readers who suffer from Dyslexia, learning to decode words may take a long time but the good news is, that once some level of decoding has been overcome, many of these readers have relatively fewer problems with fluency and comprehension. This is the opposite of the 'shallow' orthographies.

Comparative Studies
Studies between German and English have shown that the greater depth of English orthography had a "marked adverse effect on reading skills" among dyslexic children.