<scp>EEG</scp> Functional Connectivity Associated With Antidepressant Response to Transcutaneous Electrical Cranial‐Auricular Acupoint Stimulation

AIMS: Transcutaneous electrical cranial-auricular acupoint stimulation (TECAS) is an emerging neuromodulation therapy that integrates principles of acupuncture with noninvasive electrical stimulation. While TECAS has demonstrated efficacy in treating major depressive disorder (MDD), patient responses vary considerably, and the neurophysiological mechanisms remain poorly understood. This clinical study aimed to investigate electroencephalography (EEG)-based functional connectivity (FC) as a potential predictor of clinical response to TECAS in patients with MDD. METHODS: Resting-state EEG was recorded from 50 MDD patients before and after 8 weeks of TECAS treatment, and from 37 healthy controls (HCs). We compared baseline FC between MDD patients and HCs, pre-to-posttreatment changes in patients, and baseline features between treatment responders and nonresponders. Correlations between FC features and clinical symptom improvements were also assessed. RESULTS: After treatment, frontoparietal θ-band connectivity strength was significantly reduced in MDD. Crucially, pretreatment frontoparietal δ-band connectivity was negatively correlated with posttreatment reductions in depression and anxiety scores. Furthermore, responders demonstrated significantly higher pretreatment β-band FC than nonresponders. CONCLUSION: Our findings indicate that TECAS modulates frontoparietal θ connectivity in MDD. More importantly, pretreatment δ- and β-band FC patterns are associated with therapeutic outcome. These features may serve as potential biomarkers for predicting response to TECAS, facilitating the development of personalized therapeutic strategies for MDD.