Dyslexia in higher education: specific and global components of the reading profile

More and more children with dyslexia progress in their school curriculum to college, raising interest in examining the characteristics of reading disorders in adulthood. In the present study, we investigated the reading abilities of Italian college students with dyslexia, examining vocal reaction times (RTs) in reading single words. We presented the entire set of words from the Varless database, considering several psycholinguistic variables, such as length, contextual rules, N-size, word frequency, and stress. Given the baseline differences between controls and adults with dyslexia, we carried out analyses of both raw RTs and z-transformed data to control for the presence of the over-additivity effect. We examined 23 adults with dyslexia and 30 controls. Results indicated a general slowing compared to control readers. This slowing was well described by a single global factor, in keeping with the difference engine model's (DEM) predictions. Students with dyslexia were more sensitive to the influence of length and frequency; however, these interactions vanished in the z-transformed analyses, indicating that they were due to over-additivity. A similar pattern was present in the case of stress assignment, one form of orthographic inconsistency in Italian. There were subtle differences between the two groups of subjects for a few psycholinguistic parameters. Despite prolonged school attendance, college students with dyslexia still show marked RTs slowing across various word stimuli. A global factor accounted for most (although not all) of the results when using analyses capable of controlling for over-additivity.