Browsing by Subject "neuroanatomi"

Dyslexia is a specific learning disability with a neurobiological origin. Structural and functional abnormalities have been identified in the brains of people with dyslexia. These abnormalities, which are believed to arise early during fetal development, are thought to underlie the deficits in phonological skills primarily associated with dyslexia. Therefore, early identification of children at risk and detailed insight into the linguistic processes affected are important to offer personalized support measures. The aim of this thesis was to study current structural and functional findings associated with the neurobiology of dyslexia. Specifically, the study focused on how brain areas and neurobiological processes involved in reading are different in people with dyslexia compared to normal readers, and whether the same structural and functional differences can be identified in all persons with dyslexia. This work was performed as a descriptive review article, where relevant scientific original articles were screened for using search databases and a defined search phrase. The material was restricted to include articles from the last five years. The material included research on developmental dyslexia where the results had been obtained using MRI, fMRI, or MRI-based methods to obtain results with good spatial resolution. The results demonstrated structural anomalies in gray and white matter in people with dyslexia. In addition, locally abnormal brain activation patterns as well as local and global abnormalities in functional connections within and between brain areas associated with various linguistic components were demonstrated in people with dyslexia. Different subtypes of dyslexia could be differentiated based on differences in brain activity. Taken together, the results presented in this thesis show that atypical local and global patterns of gray matter and local differences in white matter characterize dyslexia. Furthermore, it is shown, that several different linguistic components are affected by dyslexia. Whether different subtypes of dyslexia can be distinguished based on structural differences remains unclear, but differentiation between subtypes of dyslexia based on differences in brain activity is possible.