Selective attention dynamics in adults with ADHD: A role for sensory processing asymmetry?

Despite persisting symptomatology in adults with ADHD, it remains elusive whether ADHD-related impairments of selective attention are domain-general or specific, whether this inattention is related to earlier stimulus encoding or later stimulus-response mappings, and whether it manifests differently in ADHD presentations. Using an intermodal selective attention task, we investigated whether and when selective attention processes across competing modalities (auditory and visual) differ in adults with inattentive (N=80) and combined (N=31) presentations, relative to unaffected adults (N=37). Using multivariate statistical inference (Partial Least Squares), we identified event-related potentials that differentiate conditions (attending, ignoring) and diagnostic groups. Compared to controls, task performance was lower in ADHD. In both modalities, effects of attending vs. ignoring were found in early (<200 ms) and late (>300 ms) processes. During the visual task, staircase-like ADHD presentation differences were found around N2 when attending to visual and around P3 when ignoring auditory stimuli. During the auditory task, late-processing ERPs were unaffected by ADHD. Instead, ADHD differences in sustained attention processes were observed across attended and ignored stimuli during early sensory processing (P1). Our data indicate that ADHD-related selective attention impairments persist into adulthood and are context-dependent (dominant during visual attention) and accompanied by altered sustained attention. In the combined presentation, post-sensory attention processes were more severely affected. The presence of an asymmetric selective attention impairment that favors auditory over visual attention does not support global selective attention deficits in adult ADHD. A discussion of clinical implications with real-life examples is provided.