Lebensalterspezifische Veränderungen phonologischer Defizite bei Lese-Rechtschreibstörung

Cross-Sectional Investigation of Brain Volume in Dyslexia

The goal of the study was to determine whether dyslexia is associated with differences in local brain volume, and whether these local brain volume differences show cross-sectional age-effects. We investigated the local volume of gray and white brain matter with voxel-based morphometry (VBM) as well as reading performance in three age groups of dyslexic and neurotypical normal reading subjects (children, teenagers and adults). Performance data demonstrate a steady improvement of reading skills in both neurotypical as well as dyslexic readers. However, the pattern of gray matter volumes tell a different story: the children are the only group with significant differences between neurotypical and dyslexic readers in local gray matter brain volume. These differences are localized in brain areas associated with the reading network (angular, middle temporal and inferior temporal gyrus as well as the cerebellum). Yet the comparison of neurotypical and normal readers over the age groups shows that the steady increase in performance in neurotypical readers is accompanied by a steady decrease of gray matter volume, whereas the brain volumes of dyslexic readers do not show this linear correlation between brain volume and performance. This is further evidence that dyslexia is a disorder with a neuroanatomical basis in the form of a lower volume of gray matter in parts of the reading network in early dyslexic readers. The present data point out that network shaping processes in gray matter volume in the reading network does take place over age in dyslexia. Yet this neural foundation does not seem to be sufficient to allow normal reading performances even in adults with dyslexia. Thus dyslexia is a disorder with lifelong consequences, which is why consistent support for affected individuals in their educational and professional careers is of great importance. Longitudinal studies are needed to verify whether this holds as a valid pattern or whether there is evidence of greater interindividual variance in the neuroanatomy of dyslexia.

Klinische Kinder- und Jugendlichen-Psychologie

Zusammenfassung. Fragestellung: Welche Entwicklungstendenzen gibt es in der Klinischen Kinder- und Jugendlichen-Psychologie in den letzten Jahren und welche Perspektiven können daraus für zukünftige Forschungsbemühungen und Veröffentlichungen abgeleitet werden? Methode: Analyse der Artikel in der Zeitschrift für Klinische Psychologie und Psychotherapie der vergangenen vier Jahre. Ergebnisse: Im Zeitraum von 2002 bis 2005 befasst sich mit Ausnahme des Jahrganges 2004 etwa ein Fünftel der Originalarbeiten mit Kindern und Jugendlichen. Arbeiten, die ausschließlich Jugendliche betreffen, sind bisher eher die Ausnahme. Die meisten Publikationen beschäftigen sich mit Angststörungen bei Kindern und Jugendlichen. Diskussion: Eine Erhöhung der Themenvielfalt bei den Arbeiten zu Kindern und Jugendlichen, insbesondere im Bereich der diagnostischen Verfahren, der untersuchten Störungsbilder sowie im Hinblick auf den Einsatz vielfältiger Behandlungsmethoden, wäre wünschenswert.

Auditory Language Comprehension in Children with Developmental Dyslexia: Evidence from Event-related Brain Potentials

In the present study, event-related brain potentials (ERPs) were used to compare auditory sentence comprehension in 16 children with developmental dyslexia (age 9–12 years) and unimpaired controls matched on age, sex, and nonverbal intelligence. Passive sentences were presented, which were either correct or contained a syntactic violation (phrase structure) or a semantic violation (selectional restriction). In an overall sentence correctness judgment task, both control and dyslexic children performed well. In the ERPs, control children and dyslexic children demonstrated a similar N400 component for the semantic violation. For the syntactic violation, control children demonstrated a combined pattern, consisting of an early starting bilaterally distributed anterior negativity and a late centro-parietal positivity (P600). Dyslexic children showed a different pattern that is characterized by a delayed left lateralized anterior negativity, followed by a P600. These data indicate that dyslexic children do not differ from unimpaired controls with respect to semantic integration processes (N400) or controlled processes of syntactic reanalyses (P600) during auditory sentence comprehension. However, early and presumably highly automatic processes of phrase structure building reflected in the anterior negativity are delayed in dyslexic children. Moreover, the differences in hemispheric distribution of the syntactic negativity indicate different underlying processes in dyslexic children and controls. The bilateral distribution in controls suggests an involvement of right hemispherically established prosodic processes in addition to the left hemispherically localized syntactic processes, supporting the view that prosodic information may be used to facilitate syntactic processing during normal comprehension. The left hemispheric distribution observed for dyslexic children, in contrast, suggests that these children do not rely on information about the prosodic contour during auditory sentence comprehension as much as controls do. This finding points toward a phonological impairment in dyslexic children that might hamper the development of syntactic processes.