Dissociating attention and arousal processes in pediatric ADHD using the Competitive Attention Test

Attention deficit/hyperactivity disorder (ADHD) is typically described as an ‘attention problem’, yet attention is not unitary. This ambiguity limits clinical interpretation because the same label can reflect different processes, including failures of voluntary orienting, exaggerated involuntary capture of attention, unstable sustained attention, or dysregulated arousal. These different facets of attention have been rarely simultaneously investigated in a same protocol. Here, we used the Competitive Attention Test (CAT) to dissociate and measure within a single paradigm voluntary attention orienting, involuntary attention, sustained attention, and phasic arousal. The performance of children and adolescents with ADHD were compared with those of age- and sex-matched typically developing (TD) peers previously tested and included in a normative database (N=50). The CAT revealed a selective profile. Voluntary attention orienting seemed preserved in patients with ADHD, and involuntary capture of attention was not increased relative to TD peers. However, patients with ADHD presented difficulties in sustained attention reflected by enhanced reaction time variability, as well as increased phasic arousal responses to unexpected stimuli. Beyond attentional measures, patients with ADHD also expressed more impulsive and hyperactive response patterns during task performance.Taken together, these results suggest that, in this sample, ADHD-related attention deficits are better characterized as a combination of sustained attention instability and arousal dysregulation than as impairments in the balance between voluntary and involuntary attention. By mapping multiple attentional processes onto dissociable behavioral measures within one task, this work provides an initial proof of concept that the CAT is particularly valuable for evaluating the ADHD population.