Effects of cue-synchronized parietal cathodal tDCS on internet gaming disorder: A randomized double-blind...

Internet Gaming Disorder (IGD) is prevalent with limited treatment efficacy. Targeting reducing craving triggered by gaming cues is a critical therapeutic objective. This study aimed to establish optimized electroencephalography (EEG) biomarkers for IGD and develop a novel targeted neuromodulation protocol.

In the exploratory study, the optimized EEG indicators of IGD diagnose were identified through machine learning models based on event-related potential (ERP) and band power during game cue exposure across two independent datasets (Dataset 1: twenty-five IGD, twenty-two Recreational Game Users, twenty-eight non-gaming Healthy Controls (HC); Dataset 2: twenty-three IGD and twenty-three HC). Subsequently, in the intervention study, a double-blind randomized trial was conducted on forty-six IGD participants to compare active and sham transcranial direct current stimulation (tDCS) targeting the region where the optimized EEG marker was located-central parietal lobe (Pz). Active stimulation (1.5 mA, 20 min, 2 days) was applied during cue exposure (cathode: Pz; anode: right trapezius).

Parieto-occipital P300 (peaked at Pz, IGD > HC) during game reactivity emerged as novel optimized EEG indicators for IGD discrimination (accuracy>80 %), linked to craving. Then, Pz targeted cathodal tDCS synchronized with game cue exposure could significantly reduce craving (p < 0.001), gaming time (p < 0.001), and P300 alpha (p = 0.048) after intervention and at 1-4 weeks follow-ups, with concomitant improvement of decision-making in the active group. Importantly, these effects generalized to unpresented gaming cues. Besides, we identified baseline delta power at Pz during gaming cues as a significant predictor for treatment effects.

Our findings establish cue-synchronized tDCS as an effective intervention approach and position the Pz as a novel therapeutic target for IGD neuromodulation.