The relation between resting EEG theta activity and poor performance in attention-demanding cognitive tasks in 46 unmedicated children/adolescents with attention deficit hyperactivity (ADHD) was studied at Westmead Hospital, University of Sydney, NSW, Australia; and Heinrich-Heine University of Dusseldorf, Germany. Accuracy and reaction time during an auditory oddball signal detection test and a visual continuous performance test were recorded. EEG power spectral analyses revealed an increase in frontal (primarily left frontal) theta activity for ADHD subjects compared to controls (F=4,18, p<0.05). Compared with control subjects, the ADHD group had significantly delayed reaction times and decreased accuracy in both cognitive tasks. In the ADHD group, correlation analyses revealed a significant relation between accuracy on the oddball task and left frontal theta, and in controls, a significant relationship between reaction time in the continuous performance test and right posterior theta. Resting theta is interpreted as an index of inattention, and spatial neurophysiologic deficits in ADHD may be related to disturbed signal detection and inattention. [1]

COMMENT. This report confirms the finding of increased theta activity in patients with ADHD, and suggests that the evidence may be predictive of errors in signal detection and attention. The authors comment that the localization of the increase in theta to the left frontal brain is consistent with reports of neuroimaging data showing a reduction in left frontal cerebral white matter. These data also refer to reduction in volume of right frontal gray matter [2]. Previous MRI studies have shown a decreased volume of the prefrontal cortex, caudate nucleus, and globus pallidus on the right side, pointing to a dysfunction of right-sided prefrontal-striatal systems in ADHD children. (Ped Neur Briefs Aug 1996) [3]