Cognitive evoked potentials in the hyperactivity attention deficit disorder

Introduction. The Attention Deficit Hyperactivity Disorder, ADHD, is characterized by deficient attention, impulsiveness and excesive motor activity. The incidence is estimated between 5 and 9% of children of school age. The P300 wave is one of the cognitive components of the event-related potential (ERP) that is more used to investigate the attention and the cognitive processes. Objective. The aim of this study was to investigate the information processing in children with ADHD predominantly inattentive type by means of the visual and auditory P300 component. Patients and methods. P300 wave using an auditory and visual oddball paradigm were recorded in 18 children with ADHD and in 18 normal children (control group). Results. We found differences in reaction time and in the porcentage of errors between children with ADHD and between controls, In the ADHD the latency of the auditory and visual P300 were significantly longer than in the control group, and the amplitude of both components were significantly smaller in the ADHD group than in controls. We didn't found differences in the cortical distribution of the P300 between the two groups. Conclusions. These data suggests that there is an abnormal processing of cognitive information in children with ADHD predominantly inattentives and a dysfunction in attentional mechanisms.