DEVELOPMENTAL SURFACE DYSLEXIA IS NOT ASSOCIATED WITH DEFICITS IN THETRANSIENT VISUAL-SYSTEM

DEFICITS of the transient visual system have been reported in unselect ed groups of dyslexics. The aim of this study was to examine whether t his finding holds when subjects with a specific type of developmental reading disorder (surface dyslexia) are considered. Ten Italian childr en were examined. They all presented the characteristic markers of sur face dyslexia: slow and laborious reading with errors in tasks which c annot be solved with a grapheme-phoneme conversion (i.e. homophones). Contrast sensitivity thresholds reversal gratings were within normal l imits for most subjects both for stimuli presented centrally and in th e right parafovea. This indicates that developmental surface dyslexia is not associated with a deficit in the transient system. In contrast, sensitivity to high spatial frequency stationary stimuli was reduced.