Bergmann-Hutzler-2005

The present study focused on early ERP differences between dyslexic and fluent readers which may reflect a deficit in letter string processing. We compared the ERPs of dyslexic and fluent readers (20 German-speaking boys in each group, age 13–14 years) in response to words and consonant strings. Due to the regularity of German orthography, our dyslexic readers suffered mainly from impaired fluency and not from errors. In a word task each trial presented short, highly frequent words and the occurrence of a pseudoword among the eight items of a trial had to be reported. In a corresponding string task each trial presented consonant strings and the occurrence of a word among the strings had to be reported. The blocked presentation allowed expectations about the nature of the stimuli and their timing. Dyslexic readers exhibited a reduced CNV in anticipation of words and strings, which in the case of words was followed by a compensatory enhanced N220. This pattern was limited to left posterior sites and may reflect a sluggish response of brain regions involved in visual letter string processing.