Affective valence and arousal in ADHD and normal boys during a startle habituation experiment

To measure two dimensions of emotion (affective valence and arousal) in 29 boys with attention-deficit hyper-activity disorder (ADHD) and 32 normal boys.

After a startle habituation experiment during which these subjects heard 40 startling sounds while watching a silent interesting movie, they were asked 12 questions (categorized a priori into questions relating to affective valence and to arousal) about their emotional reactions to these putatively unpleasant and pleasurable stimuli. Responses were recorded for the two dimensions of emotion, using two cartoon strips in each of which five expressions of a cartoon character varied linearly from happy to unhappy (affective valence dimension) and calm to excited (arousal dimension).

Factor analyses of the 12 responses revealed four factors in which the highest loadings were for affective valence to the startle responses, affective valence to the silent movie, arousal, and scary feelings. Relative to the normal group, the responses of the ADHD group were significantly biased toward pleasurable valence to the startling stimuli and to the silent movie, with a trend toward hypoarousal. Startle magnitude and habituation were similar in both groups. The normal tonic heart rate acceleration throughout the experimental session was not sustained in the ADHD group.

The self-reports of affective valence biased in the direction of pleasure and away from displeasure and the trend toward hypoarousal suggest an emotional dysfunction in ADHD.