Orthographic and lexical effects in Neglect Dyslexia: evidence from prefixation

The present study exploited Left Neglect Dyslexia (ND) to investigate how prefixation is attended to in the process of reading. ND is an acquired reading disorder that impairs the apperception of the left side of words and sentences. Importantly, both orthographic and lexical factors have been shown to modulate the exploration of written material in this syndrome. Two main issues were addressed: whether the orthographic morphological structure of prefixed words influences attention in ND; whether, and how, higher level lexical information modulates these effects. A patient with ND was asked to read prefixed and pseudo-prefixed stimuli. The patterns of errors showed that ND is sensitive to the morphological structure of stimuli: the vast majority of left errors specifically affected prefixes, an effect that could not be explained by generic neglect of the leftmost portions of the words. Additionally, errors distributed unequally depending on higher level lexical factors like semantic transparency and stem boundedness. These results are consistent with dual-route models of morphological representation and processing.