The modulation of late component event related potentials by pre-stimulus EEG theta activity in ADHD.

Electroencephalography (EEG) and Event Related Potentials (ERPs) studies in ADHD have generally been studied separately. This study examined these measures simultaneously in 54 adolescent unmedicated ADHD males and age and gender matched normal controls during an auditory oddball paradigm. Compared with controls, ADHD patients showed increased pre-stimulus EEG Theta activity and post-stimulus reduced N200 amplitude, increased P200 amplitude and delayed N200 and P300 latencies evoked to target stimuli. Moreover, Theta activity was negatively correlated with N200 amplitude and positively correlated with P200, N200 and P300 latency in ADHD. There were no correlations in the control group. Pre-stimulus preparatory state increases in Theta activity in ADHD may underlie some of the reported disturbances in information processing reflected in ADHD.