The major aim of the thesis is to investigate a new biological marker for reading proficiency. One typical marker for dyslexia is the mismatch negativity (MMN) of the auditory event-related brain potential. In the present studies I shall explore a marker that is more reading-specific: the N170 component (also called N1). This component is more reading specific because it responds to and is modulated by visual stimuli depending on the expertise of the reader with a specific stimulus class such as words or faces. In contrast, the MMN is primarily sensitive to deviant auditory stimuli in an otherwise consistent series of auditory events. The first two studies examined whether there is a correlation between habituation of the N170 and reading speed in adult normal readers and 2nd graders. The ongoing habituation of the N170 signal represents the automatization of the reading process. In a third study rhymes were used to explore the relation between N170 laterality, phonological abilities (rhyming) and reading ability/speed.

Background. Neural specialization for print develops during learning to read and can be studied with event-related brain potentials (ERPs). Neural adaptation refers to smaller neural responses when a stimulus or a class of stimuli is repeated several times. Previously, neural specialization for print processing in adults has been shown to be reflected in the word-specific N170 component of the ERP. Furthermore, adapation of the N170 elicited by words has been found to correlate with reading speed. Here, we investigated adapation of the N170-component evoked by single letters, words and faces in seven to nine- year old German-language speaking children and in a group of adult normal readers. Results. For adults, we replicated previous reports of adaptation of N170-amplitude at posterior-temporal electrodes P7 and P8 for single letters and words. For children, we only observed adaptation of N170-amplitude for single letters. No adaptation of N170-amplitude was apparent for words. However, in both, children as well as adults, N170-adaptation did not correlate with measures of reading speed. For faces, that served as a non-linguistic control condition, no adaptation of N170 amplitude was observed. Conclusions. We conclude that adaptation of the word-specific N170 component of the ERP might be linked to increasing perceptual experience with letters and words.