Electrophysiological evidence of an attentional bias towards appetitive and aversive words in adults with attention-deficit/hyperactivity disorder.

OBJECTIVE: Emotional dysregulation has emerged as a core symptom domain in adults with Attention-Deficit/Hyperactivity Disorder (ADHD). However, the pathophysiological underpinnings remain poorly understood. This study investigated attentional biases to positive and negative emotional words as possible contributing mechanisms. METHODS: Event-related potentials (ERPSs) and behavioral attention bias indices were recorded from 39 adult patients with ADHD and 41 healthy controls during a verbal dot-probe task with positive-neutral, negative-neutral, and neutral-neutral word pairs. RESULTS: Cue-locked N2pc amplitudes indicated a significant attentional bias towards emotional words in patients with ADHD and healthy controls. In healthy controls, the bias was only significant in positive trials. In patients, the bias was associated with ADHD severity and self-reported poor emotion regulation skills. ADHD patients also exhibited reduced target-locked P1 amplitudes and inferior behavioral performance compared with healthy controls. CONCLUSIONS: Our findings provide evidence of an attention bias to positive and negative emotional stimuli in adult patients with ADHD and adverse effects of emotional stimuli on task performance. SIGNIFICANCE: An attentional bias to emotional stimuli might contribute to emotional reactivity and dysregulation in adult patients with ADHD.

Deficient interference control during working memory updating in adults with ADHD: An event-related potential study.

OBJECTIVE: Little is known about the underlying mechanisms of poor working memory (WM) performance of adults with attention deficit hyperactivity disorder (ADHD). This study investigates interference and load effects during WM updating by use of event-related potentials. METHOD: Forty ADHD patients and 41 controls performed verbal n-back tasks under conditions of low and high WM load. Intrusion probes, i.e., lures, were implemented to challenge interference control abilities during WM processing. RESULTS: Stimulus-dependent N200 amplitude modulation and behavioral performance in lure trials were reduced in adults with ADHD compared to healthy controls. Also, P300 amplitudes tended to be less sensitive to WM load in patients with ADHD. CONCLUSION: Our findings provide electrophysiological evidence for inaccurate discrimination of stimulus categories. Particularly, deficient interference control may lead to overt WM deficits in adult subjects with ADHD. SIGNIFICANCE: The current findings contribute to a deeper understanding of the neural substrates of executive dysfunction in adult ADHD, focusing on the domain of WM.