Abnormalities of electroencephalography microstates in patients with depression and their association with cognitive function

Table 1 Demographic and clinical characteristics of depression group and healthy control

Variables	DEP (n = 24)	CON (n = 32)	χ2/t/W	P value
Gender (female/male)	8/16	15/17	0.555	0.4561
Age (yr)	32.4 ± 11.3	33.8 ± 10.5	0.490	0.6261
Education (years of schooling)a	13.3 ± 2.8	14.8 ± 2.7	2.056	0.0452
HAMD scorec	10 (0-23)	0 (0-6)	83	< 0.0013
Duration of illness (mo)	48.0 (24.5-195.0)
Age at onset (yr)	25.5 (16.8- 27.3)

¹Indicates P-value for Chi-square test.

²Indicates P-value for independent sample t-test.

³Indicates P-value for Wilcox Mann–Whitney test.

^aP < 0.05.

^cP < 0.001.

mean ± SD are reported for age, education; Median (interquartile range) are reported duration of illness, age at onset, HAMD score. DEP: Depression group; CON: Healthy control group; HAMD: Hamilton Depression Scale.

Table 2 Neurocognitive RBANS score of depression group and healthy control

Variables	DEP (n = 24)	CON (n = 32)	F	P value1
RBANS score
Immediate memory	85.92 ± 21.07	94.78 ± 15.57	3.559	0.145
Visuospatial/constructional	98.50 ± 17.92	94.44 ± 17.60	0.893	0.428
Language	92.92 ± 13.42	99.38 ± 14.23	3.204	0.167
Attention	104.54 ± 11.64	109.3 ± 11.74	2.755	0.196
Delayed memory	90.42 ± 18.13	94.25 ± 11.32	1.05	0.393
Total score	92.79 ± 17.66	97.78 ± 13.56	1.824	0.302

¹Indicates P value for analysis of covariance, education was controlled, and false discovery rate was used to adjust P value.

mean ± SD are reported for all variables. DEP: Depression group; CON: Healthy control group.

Table 3 Electroencephalography microstate features of depression group and healthy control

Variables	DEP (n = 24)	CON (n = 32)	F	P value1
Duration (millisecond)
Class A	70.01 ± 11.40	73.19 ± 7.35	1.70	0.314
Class B	72.20 ± 12.25	69.28 ± 6.37	1.38	0.36
Class Ca	84.58 ± 24.35	72.77 ± 10.23	6.02	0.049
Class Dc	70.00 ± 15.92	85.46 ± 10.23	19.18	< 0.001
Occurrence (Hz)
Class A	3.30 ± 0.69	3.45 ± 0.41	1.13	0.393
Class B	3.36 ± 0.50	3.24 ± 0.25	1.31	0.363
Class Ca	3.72 ± 0.56	3.41 ± 0.36	6.19	0.049
Class Da	3.18 ± 0.71	3.54 ± 0.41	5.79	0.050
Contribution (%)
Class A	23.08 ± 7.06	25.25 ± 4.70	1.96	0.292
Class B	24.05 ± 5.68	22.04 ± 3.01	3.09	0.168
Class Ca	30.39 ± 8.59	24.46 ± 4.66	10.82	0.011
Class Da	22.48 ± 8.12	28.25 ± 5.85	9.41	0.013
Transition probability (%)
Class A to B	6.94 ± 1.82	7.22 ± 1.02	0.50	0.525
Class A to Ca	9.17 ± 2.23	8.01 ± 1.42	5.94	0.049
Class A to Da	7.00 ± 2.43	8.93 ± 1.91	11.01	0.011
Class B to A	7.21 ± 1.88	7.55 ± 0.98	0.73	0.458
Class B to Ca	9.18 ± 2.69	7.45 ± 1.68	8.58	0.017
Class B to D	7.16 ± 2.88	7.49 ± 1.31	0.34	0.578
Class C to A	8.83 ± 2.05	7.77 ± 1.41	5.40	0.057
Class C to Ba	9.28 ± 2.89	7.39 ± 1.75	9.12	0.015
Class C to D	8.31 ± 2.31	8.60 ± 1.33	0.34	0.578
Class D to Aa	7.08 ± 2.38	8.89 ± 1.91	9.95	0.013
Class D to B	7.30 ± 2.84	7.99 ± 1.54	1.38	0.360
Class D to C	8.08 ± 2.40	8.30 ± 1.20	0.21	0.650

¹Indicates P value for analysis of covariance, education was controlled, and false discovery rate was used to adjust P value.

^aP < 0.05.

^cP < 0.001.

mean ± SD are reported for all variables. DEP: Depression group; CON: Healthy control group.