Objective:To analyze the electroencephalogram(EEG) average relative power spectrum in patients with unipolar and bipolar depression under the eyes-open and eyes-closed resting states.Methods:A total of 38 patients with unipolar depression (UD group), 48 patients with bipolar depression (BD group), and 43 healthy controls (HC group) were recruited from August 2022 to December 2023.The 64-channel EEG was recorded under eyes-open (EO) and eyes-closed (EC) resting states which alternated twice. The Mann-Whitney U test and Kruskal-Wallis H test were performed by SPSS 25.0 software. Results:There were no significant differences in the average relative power of delta and beta bands among the UD, BD and HC groups in all EO and EC states (all P>0.05). The average relative power of theta band in the three groups showed statistically significant differences in all EO and EC states ( H=7.852-12.583, all P<0.05). Further pairwise comparisons showed that in the first EO and EC stage, the average relative power of theta band of the UD and BD groups were significantly higher than that of the HC group (EO1: 0.18(0.17, 0.21), 0.19(0.16, 0.21), 0.16(0.14, 0.18), EC1: 0.15(0.13, 0.21), 0.15(0.13, 0.20), 0.13(0.10, 0.16); all P<0.05).In the second EO and EC stage, the average relative power of theta band of the BD group was significantly higher than that of the HC group (EO2: 0.18(0.15, 0.22), 0.16(0.14, 0.18), EC2: 0.15(0.13, 0.19), 0.13(0.11, 0.16); both P<0.05).There were statistically significant differences in the average relative power of alpha band among the three groups in the first EO and EC stage, as well as the second EC stage ( H=5.027-10.668, all P<0.05). Further pairwise comparisons showed that in the first EO stage, the average relative power of alpha band in the BD group was significantly higher than that in the UD group (0.20(0.16, 0.25), 0.14(0.11, 0.22), P=0.003), and in the following EC stages, the average relative power of alpha band in the UD group was significantly lower than that in the HC group (EC1: 0.40(0.33, 0.46), 0.51(0.40, 0.58), EC2: 0.41(0.35, 0.50), 0.48(0.43, 0.58); both P<0.05). Conclusion:At the initial stage of the resting state, both unipolar and bipolar depression patients demonstrate abnormal theta band activity under the eyes-open and eyes-closed states, while the alpha band activity under the eyes-open condition differs between the two groups of patients. These findings may provide potentially objective biomarkers to assist the diagnosis of unipolar and bipolar depression patients in clinical settings.

Objective:To analyze the electroencephalogram(EEG) average relative power spectrum in patients with unipolar and bipolar depression under the eyes-open and eyes-closed resting states.Methods:A total of 38 patients with unipolar depression (UD group), 48 patients with bipolar depression (BD group), and 43 healthy controls (HC group) were recruited from August 2022 to December 2023.The 64-channel EEG was recorded under eyes-open (EO) and eyes-closed (EC) resting states which alternated twice. The Mann-Whitney U test and Kruskal-Wallis H test were performed by SPSS 25.0 software. Results:There were no significant differences in the average relative power of delta and beta bands among the UD, BD and HC groups in all EO and EC states (all P>0.05). The average relative power of theta band in the three groups showed statistically significant differences in all EO and EC states ( H=7.852-12.583, all P<0.05). Further pairwise comparisons showed that in the first EO and EC stage, the average relative power of theta band of the UD and BD groups were significantly higher than that of the HC group (EO1: 0.18(0.17, 0.21), 0.19(0.16, 0.21), 0.16(0.14, 0.18), EC1: 0.15(0.13, 0.21), 0.15(0.13, 0.20), 0.13(0.10, 0.16); all P<0.05).In the second EO and EC stage, the average relative power of theta band of the BD group was significantly higher than that of the HC group (EO2: 0.18(0.15, 0.22), 0.16(0.14, 0.18), EC2: 0.15(0.13, 0.19), 0.13(0.11, 0.16); both P<0.05).There were statistically significant differences in the average relative power of alpha band among the three groups in the first EO and EC stage, as well as the second EC stage ( H=5.027-10.668, all P<0.05). Further pairwise comparisons showed that in the first EO stage, the average relative power of alpha band in the BD group was significantly higher than that in the UD group (0.20(0.16, 0.25), 0.14(0.11, 0.22), P=0.003), and in the following EC stages, the average relative power of alpha band in the UD group was significantly lower than that in the HC group (EC1: 0.40(0.33, 0.46), 0.51(0.40, 0.58), EC2: 0.41(0.35, 0.50), 0.48(0.43, 0.58); both P<0.05). Conclusion:At the initial stage of the resting state, both unipolar and bipolar depression patients demonstrate abnormal theta band activity under the eyes-open and eyes-closed states, while the alpha band activity under the eyes-open condition differs between the two groups of patients. These findings may provide potentially objective biomarkers to assist the diagnosis of unipolar and bipolar depression patients in clinical settings.