BRIEF RESEARCH REPORT article
Front. Cognit.
Sec. Neural Networks and Cognition
This article is part of the Research TopicArchitectures of the Resting Brain: Discrete Networks, Continuous Gradients, and Their Biological FoundationsView all articles
Temporal Variability in Pupillary Asymmetry Reflects ADHD-Related Traits in Preschool and Early School-Aged Children
Provisionally accepted
Sou Nobukawa1*
Isshu Wakita1Aya Shirama2Shingo Ofuchi1Ayumu Ueno1Kohei Okamoto3Hina Nishimura3Masahide Seto3Ayaka Yamauchi1Shuji Igawa3
Tomiki Sumiyoshi4- 1Chiba Institute of Technology, Narashino, Japan
- 2Nagoya Shiritsu Daigaku, Nagoya, Japan
- 3SMK Corporation, Tokyo, Japan
- 4National Center of Neurology and Psychiatry, Tokyo, Japan
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Attention-deficit/hyperactivity disorder (ADHD) often emerges in early childhood; however, objective validated biomarkers for its early detection remain limited. In this study, we aimed to identify pupil-based candidate physiological markers (i.e., physiological correlates) associated with ADHD-related traits in preschool-and early school-aged children. To this end, we recorded the pupil diameters of typically developing children without an ADHD diagnosis during a simple fixation task. From these data, we extracted multiple features, including the mean pupil size, temporal variability, and interocular asymmetry in both magnitude and variability. ADHD-related tendencies were assessed using the ADHD Rating Scale-5. Among the features analyzed, only the temporal variability of interocular asymmetry (VarLRdiff) showed a significant positive correlation with ADHD Rating Scale-5 total and subscale scores. This association likely reflects the combined effects of immature autonomic regulation and functional asymmetry in the neural circuits involving the locus coeruleus. In contrast, other pupil-based indices showed no significant correlations, potentially because of developmental ceiling effects and the short evaluation duration. These findings suggest that VarLRdiff may serve as a promising candidate physiological marker of ADHD-related traits in young children, requiring further validation. Future studies incorporating longer recordings, advanced analytical methods, and evaluation of test–retest stability, as well as longitudinal follow-up, are warranted to evaluate its potential utility for early screening, pending clinical and longitudinal validation.
Keywords: Attention-Deficit/Hyperactivity Disorder, Functional asymmetry, Interocular asymmetry, preschool- and early school-aged children, Pupillometry
Received: 05 Jan 2026; Accepted: 10 Feb 2026.
Copyright: © 2026 Nobukawa, Wakita, Shirama, Ofuchi, Ueno, Okamoto, Nishimura, Seto, Yamauchi, Igawa and Sumiyoshi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Sou Nobukawa
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