Contribution of oculometry and EEG synchronization in the understanding of the origin of the dyslexia: Evidence from a phonological lexical decision task in French students
Résumé
Dyslexia is a learning disability and its etiology is still debated. Phonological deficit and visuo-attentional impairment are two of the most discussed hypotheses to explain the poor reading abilities reported in dyslexia population. In this study, both eye movements and event-related potentials (ERP) were simultaneously recorded in two groups of university students, with and without dyslexia, during a phonological lexical decision task. Five categories of stimuli implicating various levels of sublexical or lexical orthographic and phonological processing were used (i.e., French content words, pseudohomophones, pseudowords, consonant strings, and symbols). We examined the number and the duration of fixations, the amplitude of saccades as well as three reading related ERP components, namely the N170, N320 and N400. Preliminary data show more and longer fixations, and several saccades in the dyslexics compared to controls, as well as reduced ERP amplitudes in the three ERP markers of interest. Taken together, these findings lend support to our assumption that dyslexia is a multifactorial deficit implicating both visual and phonological impairments.