EVALUATION OF COGNITIVE FUNCTION IN CHILDREN WITH ATTENTION DEFICIT HYPERACTIVITY DISORDER BY USING AUDITORY EVENT RELATED POTENTIALS

Background Aim - Attention deficit hyperactivity disorder (ADHD) is a childhood disorder characterized by lack of sustained attention, hyperactivity and impulsivity. Recording of Event- related potentials from the scalp is a non-invasive technique reflecting the sensory and cognitive processes associated with tasks involving attention. The aim of the present study is to assess the difference in cognitive function between normal and ADHD children using Auditory Event Related Potentials (ERP). Methods - Thirty ADHD children and 30 controls were recruited for the study. Auditory ERPs (N100, P200, N200 and P300) were recorded using auditory oddball paradigm at Pz on a computerized evoked potential recorder, after placement of electrodes using the international 10-20 system of electrode placement. Results - The ADHD children showed a statistically significant decrease in P 300 amplitude and prolongation of P 300 latency compared with the controls. When divided into two age groups, P300 latency was significantly increased in both the age groups and a smaller P300 amplitude was found in ADHD children less than 10 years of age. Conclusion - Prolonged latency of P300 shows slowing of auditory processing and decrease in P300 amplitude suggests disruption of inhibitory control in children with ADHD. These results suggest a neurocognitive abnormality in children with ADHD as indicated by ERP response.