Event-related potentials to an "oddball" auditory paradigm in children with learning disabilities with or without attention deficit hyperactivity disorder.

Event Related Potentials (ERP) were recorded during a two-tone discrimination task in 18 children with Learning Disabilities (LD) and 36 children with Learning Disabilities and Attention Deficit Hyperactivity Disorder (LD-ADHD). Twenty-seven normal children served as a control group. P3 wave amplitude was significantly smaller in the LD and LD-ADHD groups compared with normal children. There was no difference between the LD and LD-ADHD groups. It is suggested that the smaller P3 amplitude in children with LD-ADHD syndromes reflects cognitive and processing difficulties, which frequently coexist with ADHD in these children and is not specifically related to an attention deficit.