This study examined the possibility that expectancy or anticipatory reactions influence the ability to read. The Event Related Potentials (ERPs) of 10 dyslexic Mexican male students (ages 11 to 13) and eight normal male students of the same age range were evaluated. ERPs were measured while the children read words, both in and out of context, that are usually found in either introductory, intermediate, or final positions. The study found significant differences between groups in the amplitude of the ERP recording in the left occipital zone for all conditions when reading in sentences. Results suggest that children with dyslexia may have a possible deficit in stimulus expectancy and/or difficulty in the integration of auditory and visual information and the organization of motor activity. Findings also suggest that the occipital zone participates in the process of decoding verbal material and is affected in subjects with dyslexia. (Five references) (DB)