Binocular rivalry transitions predict inattention symptom severity in adult ADHD

Attention deficit and hyperactivity disorder (ADHD) is a pediatric disorder which is often maintained throughout the development and persists into adulthood. Established etiology models suggest that deficient inhibition underlies the core ADHD symptoms of inattention, hyperactivity and impulsivity. While impaired motor inhibition has been documented by numerous studies, little is known about the sensory inhibition processes, their changes throughout the development, and the relationship to ADHD symptoms. For this purpose, we employed the well-established binocular rivalry (BR) paradigm to investigate for the very first time the inhibitory processes related to visual perception in adults with ADHD. In BR, perception alternates between two dichoptically presented images throughout the viewing period, with shorter dominant percept durations and longer transition periods indicating poorer suppression/inhibition. Healthy controls (N=28) and patients with ADHD (N=32) were presented with two dissimilar images (orthogonal gratings) separately to each eye through a mirror stereoscope and asked to report their perceptual experiences. There were no differences between groups in any of the BR markers. Instead, we observed a strong association between symptom severity and the duration of transition periods in the ADHD group only; further exploratory regression analyses indicated that particularly symptoms of inattention were the best predictor of longer transition durations in adults with ADHD. The lack of impairments to sensory inhibition in adult, but not pediatric ADHD, may reflect compensatory changes associated with development, while the correlation between inhibition and inattention symptoms reveals an invariant core of the disorder