Two New Studies on ADHD and the Brain
MRI shows brain differences among ADHD patients
A study released in November 2017 by the Radiological Society of North America used MRI to compare brains of 83 children, ranging in age from of 7 to 14, with newly diagnosed and never-treated ADHD (inattentive ADHD subtype and combined subtype). Researchers compared brain MRI results with those of a control group of 87 healthy, similarly aged children.
No overall difference was found between ADHD and controls in total brain volume or total gray and white matter volumes. However, changes in the shape of three brain regions (left temporal lobe, bilateral cuneus and areas around left central sulcus) contributed significantly to distinguishing ADHD from typically developing controls. In addition, researchers found areas that differentiated between the ADHD inattentive subtype and the combined subtype.
“Psychoradiology utility of MR Imaging for Diagnosis of Attention Deficit Hyperactivity Disorder: A Radiomics Analysis.” Collaborating with Drs. Gong, Sun and Chen were Qiang Huang, Ph.D., Su Lui, Ph.D., Xiaoqi Huang, Ph.D., Yan Shi, M.D., Xin Xu, M.D., and John A. Sweeney, Ph.D. in Radiology.
Functional MRI Reveals Distinct ADHD Impairments
In another study released in November 2017, 117 adolescents with ADHD were assessed for different types of impulsive behavior. Three distinct groups emerged based on their performance: one group demonstrated impulsive motor responses during fast-moving visual tasks (a measure of executive function); another group showed a preference for immediate reward; and a third group performed relatively normally on both tasks as compared with 134 non-ADHD adolescents. The 3 ADHD subgroups were almost indistinguishable in terms of clinical symptoms.
Researchers then used functional magnetic resonance imaging (fMRI) to investigate how these different impulsivity-related test profiles related to brain dysfunction.
Each subgroup had dysfunction in different brain regions, related to their specific type of behavioral impairment, and there was not a single fMRI-measured abnormality that could be found in all three ADHD subgroups.
Stevens MC, Pearlson GD, Calhoun VD, Bessette KL. Functional neuroimaging evidence for distinct neurobiological pathways in attention-deficit/hyperactivity disorder. Biol Psychiatry, https://doi.org/10.1016/j.bpsc.2017.09.005
While MRIs and fMRIs are not yet available to diagnose ADHD, continuing research is providing more information on the neurobiological basis of ADHD and its various subtypes.
Parent perspective on their kids who have high ability and learning difficulties
In their research paper, Twice-Exceptionality: Parents’ Perspectives on 2e Identification, Lynn Dare and Elizabeth Agnes Nowicki of Western University in London, Ontario describe how they interviewed five parents of ‘twice-exceptional’ children. The children were identified with attention issues, learning disabilities, autism spectrum disorder, and emotional/behavioral disorder in addition to having ‘high ability’. They ranged in age from 11 years to early 20s and included two girls and three boys.
The authors heard from parents that twice-exceptional children have such extreme strengths and weaknesses that schooling can be an exercise in frustration. Dare and Nowicki found that “from the parents’ perspective, having a child who is highly able yet experiences learning difficulties can be challenging, confusing, and frustrating. The parents in our study were strong advocates for their children, going outside the school system to find answers to the paradoxical experience of parenting a child who is both able and struggling.” The authors expressed “concerns about how less privileged families with twice-exceptional children can be supported.”
In their concluding thoughts, Dare and Nowicki pointed out that “students struggling with twice-exceptionality often remain unrecognized until higher grades and identification of exceptionalities may not occur until parents seek professional help.” Other studies have shown that twice-exceptional children often move “from grade to grade with their educational, social, and emotional needs unmet.” Even when both exceptionalities are identified, schools tend to focus on academic weaknesses rather than offering programs to develop students’ talents.
While twice-exceptional students yearn to be accepted by their peers, many feel socially isolated and experience high levels of stress. However, the authors said that parents in their study spoke about the positive outcomes that their children could achieve as they grew into adulthood, so they saw room for optimism.
Lynn Dare & Elizabeth Agnes Nowicki (2015) Twice-Exceptionality: Parents’ Perspectives on 2e Identification, Roeper Review, 37:4, 208-218, DOI: 10.1080/02783193.2015.1077911
Brain waves study shows how different teaching methods affect reading development
A study at Stanford University found that beginning readers who focus on letter-sound relationships, or phonics, instead of trying to learn whole words, increase activity in the area of their brains “best wired for reading”. The study by Professor Bruce McCandliss of the Graduate School of Education and the Stanford Neuroscience Institute, and two colleagues, was released in May 2015 in the journal Brain and Language.
The researchers devised a new written language and contrasted whether words were taught using a letter-to-sound instruction method or a whole-word association method. After learning multiple words under both approaches, the newly learned words were presented in a reading test to the subjects while their brainwaves were monitored.
Words learned through the letter-sound instruction elicited neural activity biased toward the left side of the brain, which encompasses visual and language regions. In contrast, words learned via whole-word association showed activity biased toward right hemisphere processing.
The study’s participants who were taught using a letter-to-sound instruction method were subsequently able to read new ‘words’ they had never seen before, as long as they followed the same letter-sound patterns they were taught to focus on in the training. When the same participants memorized whole-word associations, the study found that they learned sufficiently to recognize those particular words on the reading test, but the underlying brain circuitry differed.
While this study used adult participants, the author saw implications for teaching children to read. “These contrasting teaching approaches are likely having such different impact on early brain responses because they encourage the learner to focus their attention in different ways,” McCandliss said. He noted that strong left hemisphere engagement during early word recognition is a hallmark of skilled readers, and is characteristically lacking in children and adults who are struggling with reading. “Ideally, that is the brain circuitry we are hoping to activate in beginner readers.”
Reading: Brain waves study shows how different teaching methods affect reading development. ScienceDaily: www.sciencedaily.com/releases/2015/06/150601092204.htm
Hemispheric specialization for visual words is shaped by attention to sublexical units during initial learning, Yuliya N. Yonchevaa, Jessica Wise, Bruce McCandliss, Brain and Language, Volumes 145–146, June–July 2015, Pages 23–33 http://www.sciencedirect.com/science/article/pii/S0093934X15000772
New Evidence on Dyslexia and Visual Processing
A brain-imaging study published June 6, 2013 in the journal Neuron sheds light on the question of whether the reading problems involved in dyslexia may be partially caused by visual processing difficulties. There has been evidence for many years of phonological processing difficulties underlying word recognition deficits in dyslexia (the most common learning disability). Some studies have also found visual processing weaknesses in individuals with dyslexia.
Researchers have used functional brain imaging to show less activity in the “magnocellular” visual system in children with dyslexia compared to non-dyslexic children matched on age. However, this difference no longer was seen when children with dyslexia were compared to younger, non-dyslexics matched on reading ability, suggesting that the observed difference might be tied to reading level.
In the latest study, children with dyslexia received intensive reading intervention focused largely on phonological and orthographic skills. As expected, the children made significant gains in reading but brain imaging showed that their brain’s visual system activity also increased.
Senior study author Guinevere Eden, Ph.D., director for the Center for the Study of Learning at Georgetown University Medical Center (GUMC) explains, “our results confirm that differences do exist in the visual system of children with dyslexia, but these differences are the end-product of less reading, when compared with typical readers, and are not the cause of their struggles with reading.”
A video abstract accompanies the Georgetown University paper—“Abnormal Visual Motion Processing is Not a Cause of Dyslexia,” in Neuron—and can be viewed here: www.cell.com/neuron/abstract/S0896-6273(13)00395-4#Summary
Children with nonverbal learning disabilities show differences in brain structure
A Michigan State University researcher has discovered the first anatomical evidence that the brains of children with a nonverbal learning disability – long considered a “pseudo” diagnosis – may develop differently than the brains of other children. The finding, published in Child Neuropsychology, could ultimately help educators and clinicians better distinguish between – and treat – children with a nonverbal learning disability, or NVLD, and those with Asperger’s, or high functioning autism, which is often confused with NVLD.
For more information, including a video by the researcher, go to:
Adults with ADHD commit fewer crimes when on medication
NEJM PRESS RELEASE, 22 November 2012
Criminal behaviour in people with ADHD (attention deficit hyperactivity disorder) dropped sharply during periods when they were on medication, according to a new extensive registry study conducted at Karolinska Institutet in Sweden. The study that contained of over 25,000 individuals is published in the New England Journal of Medicine (NEJM).
While previous research has shown that people with ADHD are more likely to enter a life of crime, it has remained uncertain how ADHD medication affects this risk. After having studied over 25,000 individuals with ADHD from different registries over a four-year period (2006-2009), researchers at Karolinska Institutet have now been able to examine the link between ADHD medication and criminality.
The study demonstrates in a variety of ways links between ADHD medication and a reduced risk of criminality. For example, the incidence of criminal behaviour was lower amongst medicated individuals than unmedicated ones; and in the same individual comparing periods of medication with no medication, they also found that ADHD drugs were associated with a significant risk reduction of 32 per cent. This way of studying the same individual is a particular strength in that it shows that the risk reduction is probably not attributable to differences between participants on medication and those not.
Other conclusions drawn by the study are that the observed association is not different between males and females, and applies as much to petty crime as to serious and violent crime.
Extra-large letter spacing improves reading speed & accuracy in dyslexic children
In a study released in June 2012 by the Proceedings of the National Academies of Science, a team of researchers from the University of Padova in Italy reported that extra-large spacing between letters allowed a group of Italian and French dyslexic children to read text significantly faster and with fewer than half as many errors as when they read passages with standard spacing. The authors explain that extra-large letter spacing helps reading because dyslexics are abnormally affected by crowding, a perceptual phenomenon with detrimental effects on letter recognition that is modulated by the spacing between letters. The authors acknowledge the importance of training programs that target the component skills of reading, e.g. phonological awareness, but say that after the component skills have improved, the main challenge remains — reading deficits must be treated by reading more. The extra-large spacing may help children with dyslexia read more quickly and accurately, allowing them to get the reading practice they need to improve.
New Project on Sharing Dyslexia Data (July 2012)
A project to develop methods for sharing existing data, directed by Dr. Mark Eckert at the Medical University of South Carolina and supported by the National Institute of Child Health and Human Development, is currently collecting existing data from neuroimaging studies on dyslexia. The project will establish standards for integrating biological and behavioral data from different research sites, with the goal of enhancing the power of studies to reveal etiologies and neurobiological targets for the treatment of complex disorders generally, and dyslexia specifically.
Difficulty estimating quantity linked to math learning disability
Researchers funded by the National Institutes of Health have discovered that the innate ability to estimate quantities is impaired in children who have a math learning disability.
The link between difficulty estimating quantities and math difficulties was seen only in children who had a math learning disability, and not in those who did poorly in math but were not considered to have a learning disability. Read more at: http://www.nih.gov/news/health/jun2011/nichd-17.htm
Researchers say having ADHD may actually help people think outside the box
A new study, published in the April 2011 issue of Personality and Individual Differences, suggests that individuals with ADHD are more creative than those who do not have ADHD.
Researchers gave 60 college students, half with ADHD, a series of tests measuring creativity across 10 domains — drama, music, humor, creative writing, invention, visual arts, scientific discovery, dance, architecture and culinary arts. The students also answered questions about their problem-solving styles, including preferences for generating, structuring, refining and implementing ideas.
The ADHD group scored higher on creativity across the board, the study authors said, and also exhibited a greater preference for brainstorming and generating ideas than the non-ADHD group, which preferred refining and clarifying ideas.
Do More Boys Than Girls Have Reading Problems?
Lisa Limbrick Macquarie University, New South Wales, Australia
There is controversy within the research literature concerning the relative prevalence of reading problems in boys and girls. The authors report findings from very large and very representative samples of Australian students. Data from the New South Wales Basic Skills Test (BST) for reading, administered annually to third and fifth grade students in New South Wales schools, were analyzed for 1997 to 2006. Poor readers were defined as students who scored in the lowest BST bands, Bands 1 and 2. Average boy/girl ratios for third-grade students were 1.66:1 (Band 1) and 1.44:1 (combined Bands 1 and 2) and for fifth grade students were 2.26:1 (Band 1) and 1.99:1 (combined Bands 1 and 2). The findings of this study confirm earlier research that more boys than girls experience reading problems, but these differences in incidence may be more modest than previous research has suggested.
Journal of Learning Disabilities,September/October 2010, Vol. 43 No. 5, pp. 418-429
Study demonstrates use of different brain areas in compensating for dyslexia
Brain scans of dyslexic adolescents who were later able to compensate for their dyslexia showed a distinct pattern of brain activity when compared to scans of adolescents who were unable to compensate, reported researchers funded in part by the U.S. National Institutes of Health.
The finding raises the possibility that, one day, imaging or other measures of brain activity could be used to predict which individuals with dyslexia would most readily benefit from various specific interventions.
Study demonstrates coexistence of visuospatial and phonological disorders in dyslexics
13. October 2009 00:27
Chinese-speaking children with dyslexia have a disorder that is distinctly different, and perhaps more complicated and severe, than that of English speakers. Those differences can be seen in the brain and in the performance of Chinese children on visual and oral language tasks, reveals a report published online on October 12th in Current Biology, a Cell Press publication.
English dyslexia consists of a “phonological disorder,” meaning that people with the condition have trouble detecting or manipulating the sound structure of oral language, which in turn leads to problems in mapping speech sounds onto letters, explained Wai Ting Siok of the University of Hong Kong. In contrast, the new findings show that developmental dyslexia in Chinese is really two disorders: a visuospatial deficit and a phonological disorder combined.
Siok and her colleague Li Hai Tan say the difference can be traced to the characteristics of the two languages. “In English, the alphabetic letters that form visual words are pronounceable, so access to the pronunciation of English words is made possible by using letter-to-sound conversion rules,” Siok said. “Written Chinese maps graphic forms-i.e., characters-onto meanings; Chinese characters possess a number of intricate strokes packed into a square configuration, and their pronunciations must be memorized by rote. This characteristic suggests that a fine-grained visuospatial analysis must be performed by the visual system in order to activate the characters’ phonological and semantic information. Consequently, disordered phonological processing may commonly coexist with abnormal visuospatial processing in Chinese dyslexia.”
White noise may be as effective as drugs for ADHD
Paul Taylor – Globe and Mail Update
Published Thursday, Sep. 30, 2010
Children with attention deficit hyperactivity disorder, or ADHD, are often prescribed powerful medications to help them stay focused in school. But adding white noise to a classroom may be just as effective as drugs at aiding learning among these pupils, suggest the surprising results of a Scandinavian study.
The research, led by Goran Soderlund of Stockholm University was carried out on 51 students at a secondary school in Norway.
The children were first assessed for their ability to pay attention in class. They were then given a test in which they had to remember as many items as possible from a list read out loud – either in the presence or absence of white noise. The results showed that children who normally have difficulty paying attention actually performed better when the white noise was turned on.
The researchers aren’t sure why white noise – which is made up of random signals – seems to benefit the inattentive. But Dr. Soderlund noted that people with ADHD lack adequate levels of dopamine – a chemical messenger in the brain. He speculates they are easily distracted because the reduced availability of dopamine means the brain is operating at a suboptimal level of activity.