Identifying cognitive and affective markers within an integrative neuroscience model of ADHD.

Hermens DF Kohn MR, Clarke SD, Clark CR, Gordon E & Williams LM (2006). Identifying cognitive and affective markers within an integrative neuroscience model of ADHD, Acta Neuropsychiatrica, 18, 339-.

ADHD medication treatment

Background: Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, often allied with conduct and emotional problems. Our integrative model of ADHD explores fronto-limbic-striatal networks and arousal regulation to understand poor inhibitory function in ADHD. This model provides the basis to develop new and objective assessment tools that complement subjective clinical scales in diagnostic and treatment decisions. Our objective was to identify the combination of cognitive and brain function markers that distinguish ADHD. We also evaluated these markers in response to stimulants treatment. Methods: About 175 patients with ADHD (6-16 years) tested before and after stimulant treatment were compared with 175 matched controls using the standardized Brain Resource protocols. Testing included batteries of cognitive tests and psychophysiological measures of brain function [EEG, event-related potentials (ERPs)] in response to cognitive- and emotion-related tasks. Results: Multivariate analyses showed a profile of cognitive and brain function markers that distinguished ADHD (90% sensitivity, 71% specificity, 0.76 positive predictive power, 0.88 negative predictive power). This profile comprised errors of impulsivity and intrusion, with raised slow-wave EEG, altered ERPs during inhibition and emotion processing, and autonomic dysregulation. While cognitive, EEG and inhibition- related ERP markers ?normalized? following stimulants, the emotion ERP marker did not. Autonomic markers distinguished subgroups of treatment responders. Conclusions: These findings support an integrative model of ADHD, in which impulsivity and poor inhibition are associated with dysregulation of brain function and arousal. The markers provide a platform for objective assessment to support diagnostic and treatment decisions. This work is being extended to examine whether these markers capture comorbid features of ADHD and differential response to nonstimulants. .