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Objective: This study examines the utility of new measures of event-related spatio-temporal waves in the EEG as a marker of ADHD, previously shown to be closely related to the P3 ERP in an adult sample., Methods: Wave activity in the EEG was assessed during both an auditory Oddball and a visual continuous performance task (CPT) for an ADHD group ranging in age from 6 to 18 years and comprising mostly Combined and Inattentive subtypes, and for an age and gender matched control group., Results: The ADHD subjects had less wave activity at low frequencies ( approximately 1 Hz) during both tasks. For auditory Oddball targets, this effect was shown to be related to smaller P3 ERP amplitudes. During CPT, the approximately 1 Hz wave activity in the ADHD subjects was inversely related to clinical and behavioral measures of hyperactivity and impulsivity. CPT wave activity at approximately 1 Hz was seen to "normalise" following treatment with stimulant medication., Conclusions: The results identify a deficit in low frequency wave activity as a new marker for ADHD associated with levels of hyperactivity and impulsivity., Significance: The marker is evident across a range of tasks and may be specific to ADHD. While lower approximately 1 Hz activity partly accounts for reduced P3 ERPs in ADHD, the effect also arises for tasks that do not elicit a P3. Deficits in behavioral inhibition are hypothesized to arise from underlying dysregulation of cortical inhibition.

Objective: Attention Deficit Hyperactivity Disorder (ADHD) occurs more frequently in male children and adolescents than in females, with a ratio of approximately 3 to 1. We determined whether psychophysiological differences are associated with the expression of ADHD in males and females, using simultaneously recorded electroencephalography (EEG) and electrodermal activity (EDA)., Methods: Quantitative EEG and EDA measures were acquired simultaneously and continuously (2min) during an eyes closed resting condition for 70 ADHD adolescents (48 males, 22 females) and their age- and sex-matched controls., Results: Males and females with ADHD were differentiated by both EEG theta activity and EDA. ADHD males showed increased theta (widespread), whereas ADHD females showed a localised frontal enhancement of theta with reduced rate of EDA decrement. These sex differences were unrelated to ADHD subtype., Conclusions: These findings suggest that different psychophysiological processes may underlie ADHD in each sex. The profile of theta enhancement in ADHD males is consistent with a developmental deviation model of ADHD, whereas ADHD in females may be better understood within an arousal model, which emphasizes both central and autonomic function., Significance: These findings highlight the potential for concurrent EDA measures to inform EEG studies of ADHD, particularly in regard to sex differences.

Aims: To distinguish the most sensitive markers of methylphenidate (MPH) effects on behavior and underlying biology using an integrated cognitive and brain function test battery. Methods: A randomized placebo-controlled trial with 32 healthy adult males. Subjects were tested on MPH doses across 18 sessions with subjective mood, objective behavioral and biological endpoints. From a computerized battery of tests, behavioral measures were cognitive performance scores, while biological measures of brain function included electroencephalographs (EEG) and event-related potentials (ERPs) with complementary measures of autonomic arousal. Using mixed modeling analyses; we determined which measures were most affected by MPH dose and correlation analyses determined the associations among them. Results: MPH dose had the most pronounced effect on cognitive performance (sustained attention/vigilance), baseline autonomic arousal (heart rate, blood pressure) and baseline brain activity (EEG theta power). The faster reaction time, reduced errors, increased autonomic arousal and reductions in theta showed strong to moderate inter-correlations. MPH least affected subjective mood measures and early sensory ERP components. Discussion: These findings suggest that MPH increases cortical and autonomic arousal, facilitating vigilance. The combination of behavioral and biological measures may provide an objective set of markers of MPH response. Integrative Significance: This approach has provided additional insight into the mechanism of the stimulant medication, MPH, which would not be achieved by using such measures in isolation. [ABSTRACT FROM AUTHOR]

Quantitative electroencephalography has contributed significantly to elucidating the neurobiologic mechanisms of attention-deficit hyperactivity disorder. The most consistent and robust electroencephalographic disturbance in attention-deficit hyperactivity disorder has been abnormally increased theta band during resting conditions. Separate research using attention-demanding tests has elucidated cognitive disturbances that differentiate attention-deficit hyperactivity disorder. This study attempts to integrate electroencephalographic and neuropsychological indices to determine whether cognitive performance is specifically related to increased theta. Theta activity was recorded during a resting condition for 46 children/adolescents with attention-deficit hyperactivity disorder and their sex- and age-matched control subjects. Accuracy and reaction time during an auditory oddball and a visual continuous performance test were then recorded. Compared with control subjects, the attention-deficit hyperactivity disorder group manifested significantly increased (primarily left) frontal theta. Furthermore, the attention-deficit hyperactivity disorder group scored significantly delayed reaction time and decreased accuracy in both tasks. Correlation analysis revealed a significant relationship between frontal (primarily left) theta and oddball accuracy for the attention-deficit hyperactivity disorder group compared with a significant relationship between posterior (primarily right) theta and reaction time in the continuous performance test for the control group. These results indicate that spatial neurophysiologic deficits in attention-deficit hyperactivity disorder may be related to disturbances in signal detection. This observation has important implications for the role of trait-like biologic deficits in attention-deficit hyperactivity disorder predicting performance in information processing. [Copyright &y& Elsevier]