Background: Attention-deficit/hyperactivity disorder (ADHD) is a multifaceted neurodevelopmental disorder that affects cognitive control processes. While neurophysiological data (e.g., electroencephalography [EEG] data) have provided valuable insights into its underlying mechanisms, fully understanding the altered cognitive functions in ADHD requires advanced analytical approaches capable of capturing the highly dimensional nature of neurophysiological data more effectively. 

Methods: We examined 59 individuals with ADHD and 63 neurotypical participants using a standard Go/NoGo task to assess response inhibition. We used EEG tensor decomposition to extract spectral, temporal, spatial, and trial-level features associated with inhibitory control deficits in ADHD. The trial-level features capture intraindividual variability, which is then used in a machine learning analysis to differentiate individuals with ADHD from neurotypical participants. We also applied a feature selection algorithm to identify the most important features for distinguishing the 2 groups in the classification process. 

Results: We observed typical response inhibition deficits in ADHD. Contrary to common assumptions, frontocentral theta band activity did not seem to be the most distinguishing EEG feature between ADHD and neurotypical individuals. Instead, the most important distinguishing features were tensor components reflecting posterior alpha band activity during attentional selection time windows and posterior theta band activity during response selection and control time windows. 

Conclusions: We identified novel neurophysiological facets of response inhibition in ADHD, enabling the classification of ADHD and neurotypical individuals. Our findings suggest that ADHD-related deficits emerge early during attentional selection and persist through response control stages. The findings underscore the need to refine conceptions about neural peculiarities in ADHD and adapt clinical interventions targeting inhibitory control deficits accordingly.