Domain-Specific Benefits of Online Transcutaneous Auricular Vagus Nerve Stimulation in Subclinical ADHD

Subclinical ADHD is common in adults, marked by meaningful impairments, yet treatment options for this group remain limited. Transcutaneous auricular vagus nerve stimulation (taVNS) offers a scalable neuromodulatory approach, but its behavioral effects in subclinical ADHD are poorly understood. This study tested whether online (during-stimulation) taVNS yields domain-general or domain-specific cognitive benefits. Twenty adults with elevated inattention completed two single-blind, sham-controlled, and counterbalanced sessions. Stimulation was delivered at 25 Hz to the cymba concha (active) or at 1 Hz with identical montage and sensation (sham). Participants performed the Attention Network Task (ANT: alerting, orienting, executive control) and a 2-back working memory task. ANT reaction times were analyzed with generalized linear mixed models; 2-back accuracy with linear mixed models. Blinding was successful, and only mild transient side effects occurred. Results showed that active taVNS selectively reduced flanker interference, indicating enhanced attentional control, with no effects on alerting, orienting, or working memory. These findings demonstrate a domain-specific benefit of online taVNS in subclinical ADHD, selectively strengthening executive control rather than producing broad gains across attention and memory.