Focal EEG abnormalities might reflect neuropathological characteristics of pervasive developmental disorder and attention-deficit/hyperactivity disorder

Neurophysiological characteristics in electroencephalograms (EEG) were investigated for patients with pervasive developmental disorder (PDD) and for patients with attention-deficit/hyperactivity disorder (AD/HD). This study examined 64 PDD children and 22 AD/HD children with no history of epilepsy or progressive neurological or psychiatric disorder. We used multivariate analysis to compare EEG abnormalities, clinical symptoms, and intelligence levels between PDD and AD/AD patient groups. Paroxysmal discharges at the frontopolar-frontal (Fp-F) brain regions and background EEG abnormalities tended to be detected preferentially in the PDD group, although paroxysmal discharges at central-temporal (C-T) regions tended to be detected preferentially in the AD/HD group. The paroxysmal discharges observed in patients expressing persistence and impulsivity are apparently localized respectively in the Fp-F and C-T regions. A combination of EEG abnormalities, including background EEG abnormalities and paroxysmal discharges at Fp-F and C-T regions, might be useful diagnostic hallmarks to distinguish PDD with AD/HD from AD/HD alone using a logistic regression model. The dysfunction of specific brain areas associated with EEG abnormalities might explain characteristics of clinical symptoms observed in PDD and AD/HD patients.