[Contingent negative variation in normal and dyslexic children].

The most prominent ERP to occur during intervals of preparation and anticipation is the contingent negative variation (CNV) or expectancy wave. The purpose of the study was to distinguish the characteristics of the CNV in a group of children with reading disabilities or dyslexia, and to compare it with a group of normal readers. Nine right handed boys aged between 9 and 13 years with reading disabilities were studied. The children were matched with a group of nine normal readers. Four derivations were used: F3, Cz, P3, and O1, with reference to linked ears. Data were analyzed using multivariate procedures. Significant differences between groups in the CNV amplitude at the left parietal site were observed. We discuss the participation of this zone and we consider processes like expectancy and attention in the differences observed.