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The Application of Neuroscience to the Practice of School Neuropsychology
Abstract
Translating Brain Research Into Educational PracticeThe Role of Genetics on Educational PracticeThe Role of Brain Imaging in Educational PracticeWhat Lies Ahead for the Brain Research-Education Linkage?Summary
Neuropsychologists pay much attention to career guidance for young people who are faced with the challenge of choosing the profession. Numerous studies on motivation and professional determination prove the need to identify individual features of the brain organization of mental functions in the context of psychological support for the educational process at school and career guidance. Neuropsychological research indicates the links between the predominant activity of a certain hemisphere of the brain and professional realization in certain areas. The empirical study was conducted using reliable and valid psycho-diagnostic techniques (“Questionnaire of professional self-realization” by O. M. Kokun (2014; 2016); the “Motivational profile” technique by S. Richie, & P. Martin (2004); correlation analysis). At the stage of qualitative analysis, two groups of subjects with different levels of professional self-realization were identified (using the «ace» method). A visual analysis of the motivational factors profile structure in groups with high and low levels of professional self-realisation demonstrated differences in the graphs configuration and their location, and also provided an opportunity to characterize the psychological motivation characteristics of representatives of each of the groups. Against the general background of communicative self-sufficiency, adaptability and self-confidence, in a group of persons with a high level of professional self-realisation, the dominant motives are constant improvement, recognition by others. Representatives of a group with a low level of the studied phenomenon are interested in the motives of good working conditions and high wages. It has been proved that persons with different levels of professional self-realization differ in the specificity of the dominance of motives.
Through the merging of neuroscience and education, neuroimaging will impact the field of early intervention as awareness grows concerning the developing brain. The reauthorization of the Education of the Handicapped Act Amendments and the subsequent formation of the field of early childhood special education has advanced best practices of school psychology and early intervention. Functional neuroimaging has led to advances in our understanding of brain functions enabling neuroscientists, psychologists, and educators to challenge prevailing theories and intervention approaches employed in schools today. Concerns abound when research introduces untested or unsupported instructional strategies into classroom settings based upon misinterpretation or misunderstanding of resulting data. Best practices within the fields of neuropsychology and early intervention special education does provide information regarding how children learn and provides guidance that should lead to best educational practices, but they must be based upon neuroscientific evidence which either supports traditional practices or challenges the prevailing theories.
Educational and developmental psychology faces a number of current and future challenges and opportunities in Australia. In this commentary we consider the identity of educational and developmental psychology in terms of the features that distinguish it from other specialisations, and address issues related to training, specialist endorsement, supervision and rebating under the Australian government's Medicare system. The current status of training in Australia is considered through a review of the four university programs in educational and developmental psychology currently offered, and the employment destinations of their graduates. Although the need for traditional services in settings such as schools, hospitals, disability and community organisations will undoubtedly continue, the role of educational and developmental psychologists is being influenced and to some extent redefined by advances in technology, medicine, genetics, and neuroscience. We review some of these advances and conclude with recommendations for training and professional development that will enable Australian educational and developmental psychologists to meet the challenges ahead.
This study examines the corpus callosum in 68 readers nested in 24 families. Callosa were measured and controlled for whole brain volume, intelligence, and gender. The relation of corpus callosum size to the within-family variance of oral reading was investigated with various measurements: volume, midsagittal area, and anterior-to-posterior one-fifth area segmentations. Because this is the first known publication of MRI calculations of corpus callosum volume, some basic questions about bilateral symmetry and the efficacy of area versus volumetric measurements were explored. Results suggest that better readers within families have larger midsagittal areas at the midbody. Although reliably measured, volume did not contribute to oral reading but was highly correlated with area. Bilateral volumes of the corpus callosum were symmetric.
Dyslexia is a language disorder in which reading ability is compromised because of poor phonologic skills. The purpose of this study was to measure the effect of a phonologically driven treatment for dyslexia on brain lactate response to language stimulation as measured by proton MR spectroscopic imaging.
Brain lactate metabolism was measured at two different time points (1 year apart) during four different cognitive tasks (three language tasks and one nonlanguage task) in dyslexic participants (n = 8) and in control participants (n = 7) by using a fast MR spectroscopic imaging technique called proton echo-planar spectroscopic imaging (1 cm3 voxel resolution). The age range for both dyslexic and control participants was 10 to 13 years. Between the first and second imaging sessions, the dyslexic boys participated in an instructional intervention, which was a reading/science workshop.
Before treatment, the dyslexic boys showed significantly greater lactate elevation compared with a control group in the left anterior quadrant (analysis of variance, P = .05) of the brain during a phonologic task. After treatment, however, brain lactate elevation was not significantly different from that of the control group in the left anterior quadrant during the same phonologic task. Behaviorally, the dyslexic participants improved in the phonologic aspects of reading.
Instructional intervention that improved phonologic performance in dyslexic boys was associated with changes in brain lactate levels as measured by proton echo-planar spectroscopic imaging.
Neuropsychological studies have revealed different subtypes of dyscalculia, including dissociations between exact calculation and approximation abilities, and an impact of number size on performance. To understand the origins of these effects, we measured cerebral activity with functional MRI at 3 Tesla and event-related potentials while healthy volunteers performed exact and approximate calculation tasks with small and large numbers. Bilateral intraparietal, precentral, dorsolateral and superior prefrontal regions showed greater activation during approximation, while the left inferior prefrontal cortex and the bilateral angular regions were more activated during exact calculation. Increasing number size during exact calculation led to increased activation in the same bilateral intraparietal regions as during approximation, as well the left inferior and superior frontal gyri. Event-related potentials gave access to the temporal dynamics of calculation processes, showing that effects of task and of number size could be found as early as 200-300 ms following problem presentation. Altogether, the results reveal two cerebral networks for number processing. Rote arithmetic operations with small numbers have a greater reliance on left-lateralized regions, presumably encoding numbers in verbal format. Approximation and exact calculation with large numbers, however, put heavier emphasis on the left and right parietal cortices, which may encode numbers in a non-verbal quantity format. Subtypes of dyscalculia can be explained by lesions disproportionately affecting only one of these networks.
Quantitative EEG (QEEG) can play an important role in the evaluation and treatment of children and adolescents with attention deficit and learning disorders. Children with learning disorders are a heterogeneous population with QEEG abnormality in 25% to 45% of reported cases. EEG slowing is the most common abnormal finding, and the nature of the QEEG abnormality may be related to future academic performance. Children with attention disorders are a more homogeneous population, with QEEG abnormalities in up to 80%. In this population, frontal/polar regions are most likely to show deviations from normal development, with the thalamocortical and/or septal-hippocampal pathways most likely to be disturbed. QEEG shows high sensitivity and specificity for distinguishing normal children and children with learning disorders and attention disorders from each other and may provide useful information for determining the likelihood that children with attention problems will respond to treatment with stimulant medication.
To examine changes in the spatiotemporal brain activation profiles associated with successful completion of an intensive intervention program in individual dyslexic children.
The authors obtained magnetic source imaging scans during a pseudoword reading task from eight children (7 to 17 years old) before and after 80 hours of intensive remedial instruction. All children were initially diagnosed with dyslexia, marked by severe difficulties in word recognition and phonologic processing. Eight children who never experienced reading problems were also tested on two occasions separated by a 2-month interval.
Before intervention, all children with dyslexia showed distinctly aberrant activation profiles featuring little or no activation of the posterior portion of the superior temporal gyrus (STGp), an area normally involved in phonologic processing, and increased activation of the corresponding right hemisphere area. After intervention that produced significant improvement in reading skills, activity in the left STGp increased by several orders of magnitude in every participant. No systematic changes were obtained in the activation profiles of the children without dyslexia as a function of time.
These findings suggest that the deficit in functional brain organization underlying dyslexia can be reversed after sufficiently intense intervention lasting as little as 2 months, and are consistent with current proposals that reading difficulties in many children represent a variation of normal development that can be altered by intensive intervention.
In the present study, we demonstrate for the first time the presence of an aberrant brain mechanism for reading in children who have just started acquiring reading skills. Children who, at the end of kindergarten, are found to be at risk for developing reading problems display markedly different activation profiles than children who have, at this stage, already mastered important prereading skills. This aberrant profile is characterized by the lack of engagement of the left-hemisphere superior temporal region, an area normally involved in converting print into sound, and an increase in activation in the corresponding right-hemisphere region. This finding is consistent with current cognitive models of reading acquisition and dyslexia, pointing to the critical role of phonologic awareness skills in learning to read.
We repeated a proton echo-planar spectroscopic imaging (PEPSI) study to test the hypothesis that children with dyslexia and good readers differ in brain lactate activation during a phonologic judgment task before but not after instructional treatment.
We measured PEPSI brain lactate activation (TR/TE, 4000/144; 1.5 T) at two points 1-2 months apart during two language tasks (phonologic and lexical) and a control task (passive listening). Dyslexic participants (n = 10) and control participants (n = 8) (boys and girls aged 9-12 years) were matched in age, verbal intelligence quotients, and valid PEPSI voxels. In contrast to patients in past studies who received combined treatment, our patients were randomly assigned to either phonologic or morphologic (meaning-based) intervention between the scanning sessions.
Before treatment, the patients showed significantly greater lactate elevation in the left frontal regions (including the inferior frontal gyrus) during the phonologic task. Both patients and control subjects differed significantly in the right parietal and occipital regions during both tasks. After treatment, the two groups did not significantly differ in any brain region during either task, but individuals given morphologic treatment were significantly more likely to have reduced left frontal lactate activation during the phonologic task.
The previous finding of greater left frontal lactate elevation in children with dyslexia during a phonologic judgment task was replicated, and brain activation changed as a result of treatment. However, the treatment effect was due to the morphologic component rather than the phonologic component.
Developmental dyslexia, characterized by unexplained difficulty in reading, is associated with behavioral deficits in phonological processing. Functional neuroimaging studies have shown a deficit in the neural mechanisms underlying phonological processing in children and adults with dyslexia. The present study examined whether behavioral remediation ameliorates these dysfunctional neural mechanisms in children with dyslexia. Functional MRI was performed on 20 children with dyslexia (8-12 years old) during phonological processing before and after a remediation program focused on auditory processing and oral language training. Behaviorally, training improved oral language and reading performance. Physiologically, children with dyslexia showed increased activity in multiple brain areas. Increases occurred in left temporo-parietal cortex and left inferior frontal gyrus, bringing brain activation in these regions closer to that seen in normal-reading children. Increased activity was observed also in right-hemisphere frontal and temporal regions and in the anterior cingulate gyrus. Children with dyslexia showed a correlation between the magnitude of increased activation in left temporo-parietal cortex and improvement in oral language ability. These results suggest that a partial remediation of language-processing deficits, resulting in improved reading, ameliorates disrupted function in brain regions associated with phonological processing and produces additional compensatory activation in other brain regions.
This study examined whether and how two groups of young adults who were poor readers as children (a relatively compensated group and a group with persistent reading difficulties) differed from nonimpaired readers and if there were any factors distinguishing the compensated from persistently poor readers that might account for their different outcomes.
Using functional magnetic resonance imaging, we studied three groups of young adults, ages 18.5-22.5 years, as they read pseudowords and real words: 1) persistently poor readers (PPR; n = 24); 2) accuracy improved (compensated) readers (AIR; n = 19); and 3) nonimpaired readers (NI, n = 27).
Compensated readers, who are accurate but not fluent, demonstrate a relative underactivation in posterior neural systems for reading located in left parietotemporal and occipitotemporal regions. Persistently poor readers, who are both not fluent and less accurate, activate posterior reading systems but engage them differently from nonimpaired readers, appearing to rely more on memory-based rather than analytic word identification strategies.
These findings of divergent neural outcomes as young adults are both new and unexpected and suggest a neural basis for reading outcomes of compensation and persistence in adults with childhood dyslexia.
A range of neurobiological investigations shows a failure of left hemisphere posterior brain systems to function properly during reading in children and adults with reading disabilities. Such evidence of a disruption in the normal reading pathways provides a neurobiological target for reading interventions. In this study, we hypothesized that the provision of an evidence-based, phonologically mediated reading intervention would improve reading fluency and the development of the fast-paced occipitotemporal systems serving skilled reading.
Functional magnetic resonance imaging was used to study the effects of a phonologically based reading intervention on brain organization and reading fluency in 77 children aged 6.1-9.4 years (49 with reading disability and 28 control subjects). Children comprised three experimental groups: experimental intervention (n = 37), community intervention (n = 12), and community control subjects (n = 28).
Immediately after the year-long intervention, children taught with the experimental intervention had made significant gains in reading fluency and demonstrated increased activation in left hemisphere regions, including the inferior frontal gyrus and the middle temporal gyrus; 1 year after the experimental intervention had ended these children were activating bilateral inferior frontal gyri and left superior temporal and occipitotemporal regions.
These data indicate that the nature of the remedial educational intervention is critical to successful outcomes in children with reading disabilities and that the use of an evidence-based phonologic reading intervention facilitates the development of those fast-paced neural systems that underlie skilled reading.
Reading is a complex cognitive skill that requires the coordination of multiple brain regions. Although functional neuroimaging studies highlight the cortical brain regions associated with a specific cognitive task like reading, they do not directly address the underlying neural connections necessary for efficient performance of this task. Adults with reading disability have demonstrated lower regional white matter connectivity, but it is not known whether this relationship between neuronal wiring and reading performance also holds in younger readers. Using diffusion tensor magnetic resonance imaging (DTI) that highlights the structural integrity of the brain wiring, we show that regional brain connectivity in the left temporo-parietal white matter correlates with a wide range of reading ability in children as young as 8-12 years old. Diffusion tensor tractography suggests that the posterior limb of the internal capsule is consistent with the location of the largest cluster of correlation between reading ability (Word Identification subtest) and fractional anisotropy. The maturation of the white matter may play a key role in the development of cognitive processes such as reading.
What are the cognitive and neurobiological building blocks necessary for children to acquire literacy, a skill that is crucial for academic and life achievement? In this review we discuss the behavioral and neurobiological evidence concerning the bases of reading development and impairment. The means by which reading achievement may be influenced by the background and experiences that a child brings to the classroom are discussed. Finally, we review a series of experimental studies that have examined the cognitive and neurobiological response prior to and following reading intervention in struggling readers. The importance of appropriate control groups is stressed, as well as the ultimate goal of designing reading interventions that target individual needs.
This longitudinal study examined the development of the brain mechanism involved in phonological decoding in beginning readers using magnetic source imaging. Kindergarten students were assigned to 2 groups: those who showed mastery of skills that are important predictors of proficient reading (low-risk group) and those who initially did not show mastery but later benefited from systematic reading instruction and developed average-range reading skills at the end of Grade 1 (high-risk responders). Spatiotemporal profiles of brain activity were obtained during performance of letter-sound and pseudoword naming tasks before and after Grade 1 instruction. With few exceptions, low-risk children showed early development of brain activation profiles that are typical of older skilled readers. Provided that temporoparietal and visual association areas were recruited into the brain mechanism that supported reading, the majority of high-risk responder children benefited from systematic reading instruction and developed adequate reading abilities.
Developmental dyscalculia (DD) is a specific learning disability affecting the acquisition of mathematical skills in children with otherwise normal general intelligence. The goal of the present study was to examine cerebral mechanisms underlying DD.
Eighteen children with DD aged 11.2 +/- 1.3 years and twenty age-matched typically achieving schoolchildren were investigated using functional magnetic resonance imaging (fMRI) during trials testing approximate and exact mathematical calculation, as well as magnitude comparison.
Children with DD showed greater inter-individual variability and had weaker activation in almost the entire neuronal network for approximate calculation including the intraparietal sulcus, and the middle and inferior frontal gyrus of both hemispheres. In particular, the left intraparietal sulcus, the left inferior frontal gyrus and the right middle frontal gyrus seem to play crucial roles in correct approximate calculation, since brain activation correlated with accuracy rate in these regions. In contrast, no differences between groups could be found for exact calculation and magnitude comparison. In general, fMRI revealed similar parietal and prefrontal activation patterns in DD children compared to controls for all conditions.
In conclusion, there is evidence for a deficient recruitment of neural resources in children with DD when processing analog magnitudes of numbers.
Intervention-related changes in spatiotemporal profiles of regional brain activation were examined by whole-head magnetoencephalography in 15 children with severe reading difficulties who had failed to show adequate progress to quality reading instruction during Grade 1. Intensive intervention initially focused on phonological decoding skills (for 8 weeks) and, during the subsequent 8 weeks, on rapid word recognition ability. Clinically significant improvement in reading skills was noted in 8 children who showed "normalizing" changes in their spatiotemporal profiles of regional brain activity (increased duration of activity in the left temporoparietal region and a shift in the relative timing of activity in temporoparietal and inferior frontal regions). Seven children who demonstrated "compensatory" changes in brain activity (increased duration of activity in the right temporoparietal region and frontal areas, bilaterally) did not show adequate response to intervention. Nonimpaired readers did not show systematic changes in brain activity across visits.
Developmental dyscalculia (DD) is a specific learning disability affecting the acquisition of school-level mathematical abilities in the context of otherwise normal academic achievement, with prevalence estimates in the order of 3-6%. Behavioural studies show deficits in elementary numerical processing among individuals with pure DD, indicating that deficits in higher-level mathematical skills may stem from impaired representation and processing of basic numerical magnitude. Adult neuropsychological and neuroimaging research points to the intraparietal sulcus as a key region for the representation and processing of numerical magnitude. This raises the possibility of a parietal dysfunction as a root cause of DD. We show that, in children with pure DD, the right intraparietal sulcus is not modulated in response to numerical processing demands to the same degree as in typically developing children. This finding provides the first direct evidence for a specific impairment of parietal magnitude systems in DD during non-symbolic numerosity processing.
The emerging field of neuroeducation, concerned with the interaction between mind, brain and education, has proved revolutionary in educational research, introducing concepts, methods and technologies into many advanced institutions around the world. The Educated Brain presents a broad overview of the major topics in this new discipline: part I examines the historical and epistemological issues related to the mind/brain problem and the scope of neuroeducation; part II provides a view of basic brain research in education and use of imaging techniques, and the study of brain and cognitive development; and part III is dedicated to the neural foundations of language and reading in different cultures and the acquisition of basic mathematical concepts. With contributions from leading researchers in the field, this book features the most recent and advanced research in cognitive neurosciences. © Pontifical Academy of Sciences and Cambridge University Press 2008 and Cambridge University Press, 2009.
Overview Mind, brain, and education initiatives should build bridges between educators and behavioral, cognitive, and neurobiological scientists. Some bridges are robust, and others are problematic. Links of cognitive development to education can be straightforward and useful. For example, children with low socioeconomic status typically show delays in the normal acquisition of arithmetic skills and concepts. When these children have access to intensive training, such as the program “Right Start,” they overcome the obstacles and improve their level of performance. Some other bridges are not so well founded. In particular, the over-emphasis on sensitive periods for learning connected with brain maturation has led to a restrictive concept of “windows of opportunity” for learning, which is not supported by research on learning. In fact, some research invalidates the common view that high synaptic density is needed for learning. The link from neuroscience to education needs to include assessment of the target behaviors, such as learning arithmetic and reading, and not assume that brain findings link in obvious ways. Other chapters in this book highlight areas where links between brain research and educationally relevant behaviors are being made fruitfully and with appropriate scientific caution, especially for language and arithmetic. The Editors In Education and the Brain: A Bridge Too Far (Bruer, 1997) I expressed concerns about supposed implications of developmental neuroscience for teaching and learning. I also argued positively that currently cognitive psychology is a better source for educationally relevant basic research than is developmental neuroscience. © Pontifical Academy of Sciences and Cambridge University Press 2008 and Cambridge University Press, 2009.
As the entomologist chasing butterflies of bright colors, my attention was seeking in the garden of gray matter, those cells of delicate and elegant forms, the mysterious butterflies of the soul, whose fluttering wings would someday – who knows? – enlighten the secret of mental life. Santiago Ramón y Cajal (Recuerdos de mi vida, 1981) Many scientists and educators feel that we are advancing toward new ways of connecting mind, brain, and education (MBE). This feeling arises, in part, because the disciplines related to the cognitive sciences, neurobiology, and education have made considerable advances during the last two decades, and scholars in the disciplines are beginning to seek interactions with each other (Fischer, Bernstein, & Immordino-Yang, 2006). Moreover, the increased connectivity among these disciplines has been enhanced by the growth of communication and information in the globalized world. The “digital environment” of our planet is a new phenomenon in evolution and in history (Battro, 2004), as Rita Levi-Montalcini describes in the preface to this book. We are lucky to live in a time when changes in education can rapidly reach and enrich the lives of millions. This opportunity invites us to foster the coordinated work of scientists, teachers, and students of many nations, races, and religions in the new transdisciplinary field of mind, brain, and education (Léna, 2002, and Koizumi, this volume). One name for this effort is neuroeducation (Bruer, this volume), which emphasizes the educational focus of the transdisciplinary connection. © Pontifical Academy of Sciences and Cambridge University Press 2008 and Cambridge University Press, 2009.
Second- and 3rd-grade children with poor word-level skills were randomly assigned to 8 months of explicit instruction emphasizing the phonologic and orthographic connections in words and text-based reading or to remedial reading programs provided by the schools. At posttest, treatment children showed significantly greater gains than control children in real word and nonword reading, reading rate, passage reading, and spelling, and largely maintained gains at a 1-year follow-up. Growth curve analyses indicated significant differences in growth rate during the treatment year, but not during the follow-up year. Results indicate that research-based practices can significantly improve reading and spelling outcomes for children in remedial programs. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Exposición de propuestas concretas para auxiliar en la educación lectora de personas disléxicas, dirigida quizás con mayor énfasis a padres de niños, pero con un enfoque que abarca diferentes grupos generacionales y situaciones educativas.
Brains of 18 children with dyslexia (5 girls, 13 boys) and 21 and without dyslexia (8 girls, 13 boys) were scanned before and after the children with dyslexia received instructional treatment. Both at Time 1 and Time 2 all children performed an fMRI phoneme mapping task during brain scanning-deciding whether letter(s) in pair of pronounceable nonwords could stand for the same sound. Results were analyzed with a seed point correlational method for functional connectivity from four seed points based on prior studies: inferior frontal gyrus, middle frontal gyrus, the occipital region, and cerebellum. At Time 1 before treatment, a significant difference in fMRI connectivity occurred between children with dyslexia and normal reading controls in the left inferior frontal gyrus and its correlations with right and left middle frontal gyrus, right and left supplemental motor area, left precentral gyrus, and right superior frontal gyrus. There were no significant differences for the seed regions placed in the middle frontal gyrus, occipital gyrus or cerebellum. Children with dyslexia had greater functional connectivity from the left inferior frontal gyrus seed point to the right inferior frontal gyrus than did the children without dyslexia. Compared to adults with and without dyslexia who differed in bilateral connectivity from left inferior frontal gyrus on the same task, the children with and without dyslexia differed in left side connectivity from left inferior frontal gyrus. At Time 2 after treatment, the children with dyslexia, who had participated in a three-week instructional program that provided explicit instruction in linguistic awareness, alphabetic principle (taught in a way to maximize temporal contiguity of grapheme-phoneme associations), decoding and spelling, and a writers' workshop, did not differ from the children without dyslexia in any of the clusters in the group difference map identifying differences between dyslexics and good readers, showing that functional connectivity (and not just regions of interest) may normalize following instructional treatment.
Reading and phonological processing deficits have been the primary focus of neuroimaging studies addressing the neurologic basis of developmental dyslexia, but to date there has been no objective assessment of the consistency of these findings. To address this issue, spatial coordinates reported in the literature were submitted to two parallel activation likelihood estimate (ALE) meta-analyses. First, a meta-analysis including 96 foci from nine publications identified regions where typical readers are likely to show greater activation than dyslexics: two left extrastriate areas within BA 37, precuneus, inferior parietal cortex, superior temporal gyrus, thalamus, and left inferior frontal gyrus. Right hemisphere ALE foci representing hypoactivity in dyslexia were found in the fusiform, postcentral, and superior temporal gyri. To identify regions in which dyslexic subjects reliably show greater activation than controls, 75 foci from six papers were entered into a second meta-analysis. Here ALE results revealed hyperactivity associated with dyslexia in right thalamus and anterior insula. These findings suggest that during the performance of a variety of reading tasks, normal readers activate left-sided brain areas more than dyslexic readers do, whereas dyslexia is associated with greater right-sided brain activity. The most robust result was in left extrastriate cortex, where hypoactivity associated with dyslexia was found. However, the ALE maps provided no support for cerebellar dysfunction, nor for hyperactivity in left frontal cortex in dyslexia, suggesting that these findings, unlike those described above, are likely to be more varied in terms of their reproducibility or spatial location.
Several neuroimaging studies in developmental dyslexia (DD) have mainly focused on brain regions subserving phonological processes. However, additional deficits characterize subjects with DD, such as an impairment of visual and rapid stimuli processing and deficits in implicit learning (IL). Little is known about structural abnormalities in brain regions not directly related to phonology and reading processes. The aim of this study was to investigate, using voxel-based morphometry, whether subjects with DD exhibit any structural grey matter (GM) abnormalities in regions that have previously shown abnormal functional magnetic resonance imaging (fMRI) activation during an IL task. Significantly smaller GM volumes were found in the right posterior superior parietal lobule and precuneus and in the right supplementary motor area (SMA) of subjects with DD compared to controls. Moreover, a larger GM volume in parietal cortex was associated with an increase of IL effect in controls but not in subjects with DD. These structural abnormalities are consistent with functional changes and reinforce the hypothesis that an impairment of IL might play a relevant role in learning to read.
Reading difficulties seem to be related to a phonological deficit that has its origin in poor speech perception. As such, disabled readers may use contextual cues to compensate for their weak speech perception abilities. We compared good and poor readers, 7-13 years old, on auditory perception of words varying in phonological contrast, in congruent versus incongruent sentence contexts. Both groups did worse in the phonologically similar than in the phonologically dissimilar incongruent condition. Magnetoencephalography revealed differential activation between the groups as a function of phonological contrast in left superior temporal gyrus between 200 and 300 ms, suggesting that poor readers may have processed phonologically similar incongruent stimuli as congruent. The results are consistent with a phonological account of reading disability.
Power Spectral Fast Fourier analysis of the scalp EEG was obtained from six locations, three left hemisphere and three right hemisphere, in 69 children with learning disabilities without hyperactivity and 34 control children, during baseline and while performing reading, arithmetical and spatial tasks in their schools. Significant EEG power and percent differences for specific frequencies were obtained between groups. The ability to predict attention deficit or control status was high based upon discriminant analysis for these subjects. The possibility for the supplementation of existing psychometrics with a neurometric based on power analysis of the EEG is discussed.
A review of records was carried out to examine the results obtained when people with Attention Deficit Disorder (ADD) received 40 sessions of training that combined neurofeedback with the teaching of metacognitive strategies. While not a controlled scientific study, the results, including pre- and post-measures, are consistent with previously published research concerning the use of neurofeedback with children. A significant addition is that a description of procedures is included. The 111 subjects, 98 children (age 5 to 17) and 13 adults (ages 18 to 63), attended forty 50-min sessions, usually twice a week. Feedback was contingent on decreasing slow wave activity (usually 4-7 Hz, occasionally 9-11 Hz) and increasing fast wave activity (15-18 Hz for most subjects but initially 13-15 Hz for subjects with impulsivity and hyperactivity). Metacognitive strategies related to academic tasks were taught when the feedback indicated the client was focused. Some clients also received temperature and/or EDR biofeedback during some sessions. Initially, 30 percent of the children were taking stimulant medications (Ritalin), whereas 6 percent were on stimulant medications after 40 sessions. All charts were included where pre- and post-testing results were available for one or more of the following: the Test of Variables of Attention (TOVA, n = 76), Wechsler Intelligence Scales (WISC-R, WISC-III, or WAIS-R, n = 68), Wide Range Achievement Test (WRAT 3, n = 99), and the electroencephalogram assessment (QEEG) providing a ratio of theta (4-8 Hz) to beta (16-20 Hz) activity (n = 66). Significant improvements (p < .001) were found in ADD symptoms (inattention, impulsivity, and variability of response times on the TOVA), in both the ACID pattern and the full-scale scores of the Wechsler Intelligence Scales, and in academic performance on the WRAT 3. The average gain for the full scale IQ equivalent scores was 12 points. A decrease in the EEG ratio of theta/beta was also observed. These data are important because they provide an extension of results from earlier studies (Lubar, Swartwood, Swartwood, & O'Donnell, 1995; Linden, Habib, & Radojevic, 1996). They also demonstrate that systematic data collection in a private educational setting produces helpful information that can be used to monitor students' progress and improve programs. Because this clinical work is not a controlled scientific study, the efficacious treatment components cannot be determined. Nevertheless, the positive outcomes of decreased ADD symptoms plus improved academic and intellectual functioning suggest that the use of neurofeedback plus training in metacognitive strategies is a useful combined intervention for students with ADD. Further controlled research is warranted.
Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers.
The planum temporale is clearly involved in language processing, for it serves as the auditory association cortex. Research has consistently demonstrated that 60 to 70% of the population has leftward asymmetry of the planum temporale. Research has also suggested that dyslexic individuals tend to have either rightward asymmetry or symmetrical plana. Moreover, many studies have found a relationship between the presence of dyslexia and/or language impairment and deficits in the normal right ear advantage found in dichotic listening paradigms. In this context, this study examined the relationship between planum temporale asymmetry and ear preference in dichotic listening performance in children with Developmental Dyslexia and Attention-Deficit/Hyperactivity Disorder (ADHD). Subjects included 19 children with dyslexia (10 of whom had a comorbid diagnosis of ADHD), 23 children with ADHD, and 12 diagnosed normal control children. Dichotic listening data were not collected for 8 of the 12 normal control children and for 3 of the 23 ADHD children. Results revealed no significant difference between ADHD and dyslexic subjects in regard to ear advantage on the free recall dichotic listening task. In addition, although the directed dichotic listening tasks were not related to degree of planum asymmetry, as predicted, results indicated that subjects who consistently displayed an atypical left ear advantage tended to have larger right bank lengths than those who consistently displayed a typical right ear advantage. These findings support the notion that some individuals with dyslexia or language deficits tend to have a larger right planum temporale and that performance on dichotic listening tasks may reflect this relatively unusual pattern.
To provide a description of an emerging neuroimaging methodology, near-infrared spectroscopy (nIRS), and a potential educational application of the unique aspects of this technology.
nIRS is documented for its potential as a personal, portable, brain imaging system that may prove useful for cerebral monitoring in applied settings such as home, school, and work. The basis of nIRS brain imaging is reviewed, with summary descriptions of optical and neurovascular issues as well as a brief comparison to other brain imaging methodologies. Recent developments in nIRS technology are discussed, including ongoing validation efforts and potential applications for neuropsychologists. We describe one potential application of nIRS (i.e., educational neuroimaging) as an illustration of the use of nIRS technology and the potential expansion of the neuropsychologist's role in the educational setting.
nIRS holds the potential of opening new clinical questions and opportunities for neuropsychologists, and may provide a low-cost means of repeatable, neurovascular monitoring in nonmedical settings.
To assess the effects of reading instruction on fMRI brain activation in children with dyslexia.
fMRI differences between dyslexic and control subjects have most often involved phonologic processing tasks. However, a growing body of research documents the role of morphologic awareness in reading and reading disability.
The authors developed tasks to probe brain activation during phoneme mapping (assigning sounds to letters) and morpheme mapping (understanding the relationship of suffixed words to their roots). Ten children with dyslexia and 11 normal readers performed these tasks during fMRI scanning. Children with dyslexia then completed 28 hours of comprehensive reading instruction. Scans were repeated on both dyslexic and control subjects using the same tasks.
Before treatment, children with dyslexia showed less activation than controls in left middle and inferior frontal gyri, right superior frontal gyrus, left middle and inferior temporal gyri, and bilateral superior parietal regions for phoneme mapping. Activation was significantly reduced for children with dyslexia on the initial morpheme mapping scan in left middle frontal gyrus, right superior parietal, and fusiform/occipital region. Treatment was associated with improved reading scores and increased brain activation during both tasks, such that quantity and pattern of activation for children with dyslexia after treatment closely resembled that of controls. The elimination of group differences at follow-up was due to both increased activation for the children with dyslexia and decreased activation for controls, presumably reflecting practice effects.
These results suggest that behavioral gains from comprehensive reading instruction are associated with changes in brain function during performance of language tasks. Furthermore, these brain changes are specific to different language processes and closely resemble patterns of neural processing characteristic of normal readers.
Cognitive theories of numerical representation suggest that understanding of numerical quantities is driven by a magnitude representation associated with the intraparietal sulcus and possibly under genetic control. The aim of this study was to investigate, using fMRI and structural imaging, the interaction between the abnormal development of numerical representation in an X-linked condition, Turner syndrome (TS), and the development of the intraparietal sulcus. fMRI during exact and approximate calculation in TS showed an abnormal modulation of intraparietal activations as a function of number size. Morphological analysis revealed an abnormal length, depth, and sulcal geometry of the right intraparietal sulcus, suggesting an important disorganization of this region in TS. Thus, a genetic form of developmental dyscalculia can be related to both functional and structural anomalies of the right intraparietal sulcus, suggesting a crucial role of this region in the development of arithmetic abilities.
Dyslexia seems to be related to a lack of planum temporale (PT) asymmetry that is accompanied by functional differences to control subjects in both left and right hemispheric temporal regions during language tasks. PT asymmetry has been found to correlate with phonological and verbal skills. In accordance, reduced asymmetry of the auditory N100m sources in dyslexic adults and P100m sources in dyslexic children has been reported. These results might also be related to an atypical PT symmetry or the recruitment of other structures than the PT for speech processing in dyslexia. In the present study we tried to replicate and extend previous findings by examining a sample of 64 dyslexic and 22 control children in the MEG. We measured cortical activity during a passive auditory oddball-paradigm and localised ERF sources evoked by the standard stimulus /ba/. Reduced hemispheric asymmetry in the localisation of the auditory N260m was revealed. While control children displayed a typical asymmetrical pattern with more anterior sources in the right hemisphere, this asymmetry was not present for the dyslexic children. Further, a correlation between N260m asymmetry and spelling test performance was found. Our results suggest that localisation of ERF components is indeed an applicative tool for investigating cortical deviances in dyslexia. A lack of source localisation asymmetry in dyslexia appears to be a robust finding across different samples of dyslexic children and adults. It appears that cortical auditory (language) processing is organised differently in dyslexic subjects than in controls. This might be the consequence of a more symmetrical PT organisation, which in turn might be the result of maturational delay.
Rapidly accumulating evidence from functional brain imaging studies indicates that developmental reading disability is associated with a functional disruption of the brain circuits that normally develop to support reading-related processes. This article briefly overviews recent advances in methods that capture the anatomical outline and temporal (dynamic) features of regional brain activation during performance of reading tasks. One of these methods, magnetoencephalography (MEG) or magnetic sources imaging (MSI) is described in more detail in the context of investigations of changes in spatiotemporal patterns of brain activity associated with improvement in reading skills in response to various types of educational interventions.
Fifteen children ages 7 to 9 years who had persistent reading difficulties despite adequate instruction were provided with intensive tutorial interventions. The interventions targeted deficient phonological processing and decoding skills for 8 weeks (2 hours per day) followed by an 8-week, 1-hour-per-day intervention that focused on the development of reading fluency skills. Spatiotemporal brain activation profiles were obtained at baseline and after each 8-week intervention program using magnetoencephalography during the performance of an oral sight-word reading task. Changes in brain activity were found in the posterior part of the middle temporal gyrus (Brodmann's Area [BA] 21: increased degree of activity and reduced onset latency), the lateral occipitotemporal region (BA 19/37: decreased onset latency of activation), and the premotor cortex (increased onset latency). Overall changes associated with the intervention were primarily normalizing, as indicated by (a) increased activity in a region that is typically involved in lexical--semantic processing (BA 21) and (b) a shift in the relative timing of regional activity in temporal and frontal cortices to a pattern typically seen in unimpaired readers. These findings extend previous results in demonstrating significant changes in the spatiotemporal profile of activation associated with word reading in response to reading remediation.
This study used fMRI to longitudinally assess the impact of intensive remedial instruction on cortical activation among 5th grade poor readers during a sentence comprehension task. The children were tested at three time points: prior to remediation, after 100 h of intensive instruction, and 1 year after the instruction had ended. Changes in brain activation were also measured among 5th grade good readers at the same time points for comparison. The central finding was that prior to instruction, the poor readers had significantly less activation than good readers bilaterally in the parietal cortex. Immediately after instruction, poor readers made substantial gains in reading ability, and demonstrated significantly increased activation in the left angular gyrus and the left superior parietal lobule. Activation in these regions continued to increase among poor readers 1 year post-remediation, resulting in a normalization of the activation. These results are interpreted as reflecting changes in the processes involved in word-level and sentence-level assembly. Areas of overactivation were also found among poor readers in the medial frontal cortex, possibly indicating a more effortful and attentive guided reading strategy.
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