424. IDENTIFYING SPECIFIC EEG MARKERS OF INTERNET GAMING DISORDER AND THE CORRESPONDING TDCS INTERVENTION: A RANDOMIZED CONTROLLED DOUBLE-BLIND STUDY

Abstract Background Internet Gaming Disorder (IGD) has been classified as a behavioral addiction, with its prevalence increasing annually. Electroencephalography (EEG) monitoring techniques have emerged as vital tools in the investigation of brain function indicators and intervention strategies for psychiatric disorders. Transcranial direct current stimulation (tDCS) can modulate cognitive mental states by altering cortical activation. However, there are relatively few studies for the effective EEG markers for IGD and the EEG-based tDCS intervention under cue-reactivity task. Aims & Objectives The objective of this study is to identify EEG indicators associated with IGD and predicting craving by using machine learning model. tDCS interventions were conducted during cue exposure to target the identified changes in specific cortical neuroelectric activity. Method The EEG changes observed in IGD (DSM-5 ≥ 6; ≥ 14 hours per week in game), recreational game users (RGU, DSM-5 < 5; ≥ 14 hours per week in game), and healthy controls (HC, DSM-5 < 5; < 7 hours per week in game) during gaming cue exposure task were collected and analyzed. EEG features were extracted for machine learning to identify specific cortical neuroelectric activities that can distinguish IGD and to further assess the association between with craving. tDCS intervention study was conducted over 2 days (20 minutes each session) on the identified cortical alterations, employing a randomized controlled double-blind design under cue exposure. Results Based on basic and EEG data of 25 IGD, 22 RGU, and 18 HC, we found the notable P300 component in parieto-occipital lobe during cue-reactivity task, while N400 component exhibited a significant reduction in prefrontal and central regions. The machine learning model of all energy frequency band effectively distinguished between IGD and other groups (AUC>0.8). Among the various features of P300 component, Pz (parietal lobe) was particularly influential (only Pz: AUC=0.74, except Pz: AUC=0.66), the Delta, Theta, and Alpha band energies of P300 at Pz were positively correlated with the current craving of IGD. Subsequently, tDCS incorporating game cue exposure was conducted at Pz for 46 IGD (23 in active/sham separately). Compared to sham group, active group exhibited significantly lower levels of craving and reduced game usage time following intervention and at 1-4 weeks post-intervention. Notably, the mean amplitude of P300 component at Pz, along with Delta, Theta, and Alpha band energies, were all significantly lower in active group, which maintained significantly superior effects at 1-week post-intervention. Discussion & Conclusions The P300 component in PZ was significantly enhanced in IGD under cue-exposure conditions and serve as significant electrophysiological indicators for distinguishing IGD status. Furthermore, the tDCS cathodic intervention targeting Pz during cueing task effectively reduced both craving and playtime in IGD with long-term effects. The findings of this study offer novel EEG-target for the diagnosis and intervention of IGD.