Searching for mechanisms of dyslexia: a multidimensional study of cognitive deficits and their neural underpinnings
Project Leader: Anna Grabowska, Prof.
Grant MAESTRO (2014/14/A/HS6/00294, Nencki Institute)


Theories of developmental dyslexia differ on how to best interpret the great variety of symptoms (linguistic and non-linguistic) observed in dyslexic individuals. Although, the most common are the phonological deficits, many other cognitive deficits seem to contribute to impairment in reading acquisition. Despite the heterogeneous nature of dyslexia, it was not until recently, when researchers started to consider the need to differentiate specific dyslexic subtypes based on the pattern of co-occurring cognitive deficits and describe their neuronal correlates. However, most of these studies were too narrow to capture the full scope of dyslexic symptoms. The proposed project is the first multidimensional approach to study the cognitive and neurobiological basis of reading impairment taking into concern all issues regarded as crucial for understanding the disorder, i.e.: behavioral manifestation, broad characteristics of cognitive deficits and their neuronal correlates. Further, by studying the effects of therapy directed at specific deficit, we plan to establish causal relationships between the cognitive deficits and dyslexia rather than show their co-occurrence. Lastly, longitudinal examination of children at the start of school education will enable us to establish the risk factors for dyslexia.
The main objective of the proposed research is to define the etiology of developmental dyslexia by investigating the relationship between a variety of deficits known to contribute to reading disorder at three levels of analysis: behavioral, cognitive and neuronal. Based on those data, dyslexic subtypes with different profile of cognitive deficits will be distinguished and characterized on the neuronal level (both functional and structural MRI will be acquired). The results of remediation strategies directed at deficient cognitive functions would be also investigated, at three above-mentioned levels of analysis. Hence we will be able to verify the validity of identified subtypes and their mechanisms. What is more such an approach will allow us to test the neural predispositions for successful intervention. Additionally, a longitudinal approach will be applied to test the possibility that specific cognitive deficits characterized of unique brain abnormalities can be identified in children at the start of school education and whether they can be viewed as risk factors for developing dyslexia.