The psychophysiology of reading

Abstract

Early identification of dyslexia would be fundamental to prevent the negative consequences of delayed treatment in the social, psychological and occupational domains. Movement-related potentials of dyslexic children are characterized by inadequate ability to program movements and reduced capacity to evaluate their performance and to correct their errors. Reading-related potentials recorded during different reading conditions elicit a series of positive and negative components with specific functional meaning and with a characteristic spatial-temporal pattern. These reading-related potentials, when analyzed with sLORETA, show significantly different patterns of activation when comparing self-paced reading aloud to passive viewing of single letters. Comparison of fMRI and sLORETA during both tasks showed that the cortical region with the widest inter-modality similarities is the middle-superior temporal lobe during self-paced reading aloud. Neuropsychological studies have shown the existence of clinical subtypes of dyslexia; these studies have been confirmed by the results of ICA applied to the EEG. Dyslexia can be defined as a disorder of programming and integrating ideokinetic elements, associated with a deficiency in the fast processing and integration of sensory information, with reduced efficiency of error systems analysis. Each of these phenomena occurs at different levels of the central nervous system and at different times.

Keywords: Dyslexia; Movement-related potentials; Reading-related potentials; Subtypes of dyslexia.