The main diagnostic criterion for developmental dyslexia (DD) in transparent orthographies is a remarkable reading speed deficit, which is often accompanied by spelling difficulties. These deficits have been traced back to both deficits in orthographic and phonological processing. For a better understanding of the reading speed deficit in DD it is necessary to clarify which processing steps are degraded in children with DD during reading. In order to address this question the present study used EEG to investigate three reading related ERPs: the N170, N400 and LPC. Twenty-nine children without DD and 52 children with DD performed a phonological lexical decision (PLD)—task, which tapped both orthographic and phonological processing. Children were presented with words, pseudohomophones, pseudowords and false fonts and had to decide whether the presented stimulus sounded like an existing German word or not. Compared to control children, children with DD showed deficits in all the investigated ERPs. Firstly, a diminished mean area under the curve for the word material-false font contrasts in the time window of the N170 was observed, indicating a reduced degree of print sensitivity; secondly, N400 amplitudes, as suggested to reflect the access to the orthographic lexicon and grapheme-phoneme conversion, were attenuated; and lastly, phonological access as indexed by the LPC was degraded in children with DD. Processing differences dependent on the linguistic material in children without DD were observed only in the LPC, suggesting that similar reading processes were adopted independent of orthographic familiarity. The results of this study suggest that effective treatment should include both orthographic and phonological training. Furthermore, more longitudinal studies utilizing the same task and stimuli are needed to clarify how these processing steps and their time course change during reading development.

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Die Lese-Rechtschreibstörung (LRS) ist eine der häufigsten umschriebenen Entwicklungsstörungen schulischer Fertigkeiten und bleibt meist bis ins Erwachsenenalter bestehen. Schulische Schwierigkeiten und psychische Störungen sind oft Begleitsymptome der LRS. Aus diesem Grund ist nachhaltige Förderung von größter Bedeutung. Die Fördereffekte bisheriger Interventionsstudien sind jedoch recht gering, und vielen Studien mangelt es an ausreichender methodischer Fundierung. Ziel dieser Studie ist daher die Überprüfung zweier Interventionsprogramme in einem Prä-Post Experimental-Warte-Kontrollgruppendesign. Vier Gruppen von Drittklässlern nahmen an der Studie teil. Zwei Gruppen von Kindern mit LRS (n = 40) wurden über sechs Monate zweimal wöchentlich mit einem Lese- oder Rechtschreibprogramm gefördert und mit einer Wartegruppe (n = 17), die erst nach sechs Monaten gefördert wurde, sowie einer nicht betroffenen Kontrollgruppe (n = 26) verglichen. Die quantitative und qualitative Analyse der Lese- und Rechtschreibleistungen vor und nach der Förderung zeigte, dass sich alle Kinder mit LRS signifikant verbesserten. Betrachtungen auf individueller Ebene zeigten jedoch auch, dass eine deutlich spezifischere Zuweisung zu einzelnen Förderprogrammen notwendig ist. Eine Überlegenheit einer einzelnen Gruppe fand sich nicht. Da sich auch die Wartegruppe der unbehandelten Kinder mit LRS verbesserten, können keine eindeutigen Schlüsse über die Effektivität der Förderung gezogen werden. Die Gründe hierfür sind unklar, müssen aber unbedingt verstanden werden. Hierzu fehlen jedoch weltweit Studien. Es ist dennoch zwingend notwendig, die spezifischen von den unspezifischen Fördereffekten zu unterscheiden. Eine Studie mit einer Placebogruppe mit gleicher Förderdauer und Zuwendung und einer unbehandelten Kontrollgruppe sowie eine nicht randomisierte und individuelle Zuweisung zu spezifischen Förderprogrammen könnte hierfür ein sinnvoller Lösungsansatz sein.

Intervention is key to managing developmental dyslexia (DD), but not all children with DD benefit from treatment. Some children improve (improvers, IMP), whereas others do not improve (non-improvers, NIMP). Neurobiological differences between IMP and NIMP have been suggested, but studies comparing IMP and NIMP in childhood are missing. The present study examined whether ERP patterns change with treatment and differ between IMP and NIMP. We investigated the ERPs of 28 children with DD and 25 control children (CON) while performing a phonological lexical decision (PLD) task before and after a 6-month intervention. After intervention children with DD were divided into IMP (n = 11) and NIMP (n = 17). In the PLD–task children were visually presented with words, pseudohomophones, pseudowords, and false fonts and had to decide whether the presented stimulus sounded like an existing German word or not. Prior to intervention IMP showed higher N300 amplitudes over fronto-temporal electrodes compared to NIMP and CON and N400 amplitudes were attenuated in both IMP and NIMP compared to CON. After intervention N300 amplitudes of IMP were comparable to those of CON and NIMP. This suggests that the N300, which has been related to phonological access of orthographic stimuli and integration of orthographic and phonological representations, might index a compensatory mechanism or precursor that facilitates reading improvement. The N400, which is thought to reflect grapheme-phoneme conversion or the access to the orthographic lexicon increased in IMP from pre to post and was comparable to CON after intervention. Correlations between N300 amplitudes pre, growth in reading ability and N400 amplitudes post indicated that higher N300 amplitudes might be important for reading improvement and increase in N400 amplitudes. The results suggest that children with DD, showing the same cognitive profile might differ regarding their neuronal profile which could further influence reading improvement.