Peripheral developmental dyslexia: a visual attentional account?

Abstract

We report the case of Olivia, a 10–year-old developmental dyslexic whose reading age is 7 years 7 months. Most of her reading errors are visual paralexias and she makes neither semantic errors nor errors of regularisation. Her reading error pattern is thus analogous to that previously described in acquired visual dyslexia. Neuropsychological assessment shows that reading accuracy is not affected by variables such as word frequency, word length, spelling regularity, or the lexical dimension of the printed stimuli. The analysis of visual errors reveals the existence of a frequency bias, direct count word frequency of the production being on average higher than that of the stimulus. However, performance on lexical decision tasks suggests that Olivia's misreadings reflect an initial word misidentification. Overall, the analysis points to a dysfunction ascribed at a relatively peripheral level of processing. Olivia's paralexias are interpreted as reflecting primarily a visual attentional impairment. Such a peripheral dysfunction seems to have no major consequence on the development of the reading system but prevents access to an automatic level of word recognition.