Endogenous and exogenous covert attention are functionally intact in adults with ADHD

Abstract

Purpose. Is visuospatial covert attention –the selective processing of visual information in the absence of eye movements– preserved in adults with Attention-Deficit/Hyperactivity Disorder (ADHD)? A few studies suggest that the effects of attention on early visual processes in adults with ADHD resemble neurotypical adults. However, imprecise terminology, variability in experimental design and reliance on only reaction time limit these conclusions. To address these limitations, we used spatial cueing protocols that have been well-established in neurotypical and special populations to assess accuracy and speed of processing in a basic visual task. Methods. We adjusted stimulus contrast to equate task difficulty across individuals in a neutral, distributed cue condition. Fourteen ADHD adults and 14 age- and gender-matched controls performed a 2AFC orientation discrimination task. We manipulated exogenous (Experiment 1) or endogenous (Experiment 2) covert spatial attention via presentation of a peripheral or central spatial cue, respectively. Eye fixation was ensured. Attentional "benefits" (Experiments 1 & 2) and "costs" (Experiment 2) were calculated relative to the neutral condition. Results. For both groups, attention significantly improved accuracy and decreased reaction times to a similar extent in both experiments. Moreover, deployment of endogenous attention away from the target location significantly impaired accuracy to the same degree (Experiment 2). Only the ADHD adults demonstrated a reorienting hemifield asymmetry, i.e. significantly slower responses to targets when the invalid cue was on the right than left visual field. Both groups performed better along the horizontal than vertical meridian as well as lower than upper vertical meridian, and showed similar effects of attention at all isoeccentric locations. Conclusion. Despite the disorder's name, in adults with ADHD both endogenous and exogenous covert spatial attention remain functionally intact for basic visual tasks. Moreover, they exhibit the same perceptual asymmetries and attention effects around the visual field as neurotypical observers.

Meeting abstract presented at VSS 2017