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Neural print tuning and persistence of dyslexia

English title Neural print tuning and persistence of dyslexia
Applicant Brandeis Daniel
Number 125407
Funding scheme Project funding (Div. I-III)
Research institution Kinder- und Jugendpsychiatrischer Dienst Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Neurology, Psychiatry
Start/End 01.04.2009 - 31.01.2013
Approved amount 398'403.00
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Keywords (13)

dyslexia; reading ; development; expertise; N1; EEG; fMRI; simultaneous; illiteracy; persistence; outcome; ERP;

Lay Summary (English)

Lead
Lay summary
Aims: Developmental dyslexia, a specific reading disorder, affects 5-10% of the school children. Although diagnosed as a failure of learning to read in childhood, dyslexia often persists into adulthood, and contributes significantly to the high prevalence of illiteracy. Brain imaging has revealed a major role of reduced coarse visual tuning for print in dyslexic children [1, 2], but whether this persists in adults with dyslexia remains open. Here, we examine visual print processing in adolescents and adults, using functional brain mapping with EEG (Electroencephalogram) and fMRI (functional magnetic resonance imaging). A first core question is whether visual print tuning remains impaired in older, persistently dyslexic readers under realistic reading conditions. A second core question is whether behavioural and brain markers from kindergarten can predict persistent dyslexia in our longitudinal sample [3], and how print tuning changes during late development.Context and impact: The study will clarify how illiteracy in adulthood relates to dyslexia as typically diagnosed in childhood. The study will further clarify the role of visual tuning deficits for dyslexia beyond school age. How such impaired brain processes develop is of practical relevance for conceptualizing age-appropriate training programs for dyslexia. Methods: Adolescents who already participated in our longitudinal study in kindergarten, 2nd grade and 5th grade are followed up in 9th grade. Reading and spelling abilities are assessed first. During simultaneous EEG-fMRI recordings, participants then perform additional reading tests engaging brain mechanisms specialized for processing print. To increase group sizes, additional dyslexic and non-dyslexic adolescents who participated only in 5th grade are also invited. The same protocol will also be run with groups of dyslexic and non-dyslexic adults.1) Maurer, U., Brem, S., Bucher, K., Kranz, F., Benz, R., Halder, P., Steinhausen, H.-C., & Brandeis, D. (2007). Impaired tuning of a fast occipito-temporal response to print in dyslexic children learning to read. Brain, 130, 3200-3210.2) Van der Mark, S., Bucher, K., Maurer, U., Schulz, E., Brem, S., Buckelmüller, J., Kronbichler, M., Loenneker, T., Klaver, P., Martin, E., & Brandeis, D. (in press). Dyslexia in children: dysfunction of specialization within the Visual Word-Form (VWF) system. Neuroimage.3) Maurer, U., Bucher, K., Brem, S., Benz R., Kranz, F., Schulz, E., van der Mark, S., Steinhausen, H.-C., Brandeis, D. (2009). Neurophysiology in preschool improves behavioral prediction of reading ability throughout primary school. Biological Psychiatry, 66, 341-348.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Visual print tuning deficits in dyslexic adolescents under minimized phonological demands.
Kronschnabel Jens, Schmid Raffaella, Maurer Urs, Brandeis Daniel (2013), Visual print tuning deficits in dyslexic adolescents under minimized phonological demands., in NeuroImage, 74, 58-69.

Collaboration

Group / person Country
Types of collaboration
Prof. Dr. Hansjakob Schneider / Fachhochschule Nordwestschweiz Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Lesen und Schreiben Bern / Hans Joss Switzerland (Europe)
- Industry/business/other use-inspired collaboration
Verband Dyslexie Schweiz Switzerland (Europe)
- Industry/business/other use-inspired collaboration

Associated projects

Number Title Start Funding scheme
108130 Developing neural specialization for print and dyslexia 01.04.2005 Project funding (Div. I-III)
141201 Neuronal markers of grapheme-phoneme training response for prediction of successful reading acquisition in children at familial risk for developmental dyslexia 01.07.2013 Project funding (Div. I-III)
130237 Neuroimaging of cognitive flexibility and action monitoring in paediatric obsessive-compulsive disorder (OCD) and attention deficit-hyperactivity disorder (ADHD) 01.11.2010 Project funding (Div. I-III)

Abstract

Background and questions: Developmental dyslexia is a specific reading disorder affecting about 5-10% of the school children. Although diagnosed as a failure of learning to read in childhood, dyslexia often persists into adolescence and adulthood, and contributes significantly to the high prevalence of persistent illiteracy. Brain imaging studies of reading have revealed that visual tuning for print is reduced in dyslexia, in addition to reduced activation associated with phonological processing. These visual tuning impairments, however, are not consistently observed during development across adults, adolescents, children, or across different tasks, suggesting that either neural mechanisms of dyslexia change with development, or alternatively are influenced by processing demands. A first core question is whether impaired visual print tuning still plays a role in older, persistently dyslexic readers under realistic, age-appropriate reading conditions, possibly dependent upon specific top-down or bottom-up processing constraints. As different imaging techniques (fMRI vs. EEG) may be sensitive to different aspects of visual tuning, an additional question is whether these measurements may be brought to converge in normal reading, and to consistently characterize visual tuning deficits in persistent dyslexia under age-appropriate reading conditions. Although longitudinal brain imaging studies have proven most powerful for understanding developmental disorders, no such results are available for dyslexia beyond primary school. A second core question is thus whether extending our longitudinal study to adolescence will allow us to predict the persistence of reading ability based on behavioural and ERP measures from kindergarten, and how print tuning changes throughout development from childhood to adolescence.Specific Aims: Longitudinal neurophysiological mapping will clarify the developmental trajectory of print tuning in normal controls and in dyslexic participants enabling comparisons at 4 time points (kindergarten, 2nd grade, 5th grade, 9th grade) for EEG data and at 2 time points (5th grade, 9th grade) for fMRI data. Adding adult groups of controls and dyslexics, and manipulating bottom-up and top-down processing will clarify the role of print tuning for persistence of dyslexia throughout adolescence and adulthood, and will facilitate comparison to literature about adult dyslexia. Multimodal integration of EEG and fMRI recordings will further characterize the neural basis for persistence of dyslexia at a high temporal and spatial precision.Working Hypotheses: Coarse tuning of visual processes for print continues to play an important role for dyslexia in adolescence and in adulthood, but impairment increasingly depends on processing demands. Compensatory or task irrelevant processing differentially affects the ERP and fMRI measures: fast print-tuning (N1 ERP component) is more influenced by bottom-up, perceptual processes (presentation duration/rate of stimuli), while print-tuning measured by fMRI (Visual Word Form System, VWFS) is more influenced by top-down processes. However, under high, age-appropriate demands upon fluent reading, ERP and fMRI evidence should converge on fast print tuning deficits in the VWFS. Experimental Design and Methods: The follow-up of our longitudinal sample in 9th grade will apply the test of visual print tuning used in previous recordings with the same subjects plus additional experiments manipulating bottom-up and top-down processing influence. Tests will use simultaneous EEG-fMRI, and reading and spelling will be measured behaviorally. From the longitudinal study at least 46 children will be recorded (including at least 12 dyslexic children and 12 control children from low risk families). The sample size will be increased to 16 for the dyslexia and low-risk controls in the following year by recruiting children who have previously participated in a cross-sectional part of the study. Additionally, 16 adult dyslexics and 16 age-matched controls will be recruited and run with the same tests. In sum, around 80 participants will take part in the simultaneous EEG-fMRI recordings.Expected Value: Longitudinal studies are critical to map individual developmental trajectories of visual tuning for print, and the results will resolve inconsistencies in the literature about tuning deficits in dyslexia. Critically, the results will clarify whether print tuning is impaired beyond school age under realistic, age-appropriate reading conditions. This has important implications for the therapeutic focus of reading intervention programs being developed to remediate persistence of dyslexia in adolescents and adults, and in particular on whether training forms involving high demands upon rapid visual print processing and reading fluency are supported also in these age groups.
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