Abstract
<p>Purpose: In developmental dyslexia, inefficient orthographic processing might underlie poor reading. This study investigated whether letter-specific orthographic processing is selectively impaired in developmental dyslexia or whether deficits in visual sensitivity and position coding extend to other characters such as digits or unfamiliar symbols. Method: Event-related potentials (ERPs) were recorded from Hungarian adults with (N = 26) and without dyslexia (N = 26) while they viewed pairs of Latin pseudowords, Arabic digit strings, and unfamiliar Armenian letter strings an implicit feature-detection version of the same–different task. Each stimulus pair was either identical, differed by substitution of one character, or differed by the positions of two characters. Results: The point-by-point ANOVA analysis revealed that (a) N1 visual sensitivity is greater for both letters and digits compared to unfamiliar characters, (b) readers with and without dyslexia had similar N1 responses across stimuli, (c) identity and position coding extend beyond letters but the time course, distribution, and relative magnitude of these effects vary by stimulus type, and (d) these coding processes are comparable in dyslexic and typical readers.</p>