EEG coherence and IGD Based on the significant group differences revealed by the GEE analyses, the correlations between the beta and gamma intrahemispheric coherence values of each electrode pair and the degree of Internet addiction tendency, as assessed by the Internet Addiction Test (IAT), were investigated. For all groups, there was a significant correlation between F4-C4 gamma coherence and the IAT score (R = 0.243, P = 0.012; Fig. 3) but the correlations between the EEG variables and the severity of IGD were not significant in the IGD group (all P-values > 0.050). The intrahemispheric beta coherence values were not correlated with the IAT score.Figure 3Correlation between the F4-C4 gamma coherence and the score on IAT. The scatter plot presents the correlation between variables in IGD (red circle), AUD (blue square), and HC (green triangle) groups. Fisher’s Z-transformed scores were used for the EEG data. 2000 sample bootstrapping was applied with Pearson’s correlation, and the significance level was set at 0.050. IGD = Internet gaming disorder; AUD = alcohol use disorder; HC = healthy control; EEG = electroencephalography. Next, hierarchical
