Neural correlates of attentional switching dysfunction in major depressive disorder: Evidence from an event-related potential study with a dual-task paradigm

Table 1 Demographic and clinical characteristics of participants, mean ± SD

Variables	MDD (n = 29)	HC (n = 29)	Test statistic
Age (years)	25.0 (3.20)	30.31 (6.40)	P = 0.063
Sex (M/F)	11/18	14/15	χ2 = 0.633, P = 0.426
Education (years)	15.02 (4.50)	15.45 (2.50)	P = 0.063
Age at onset (years)	24.17 (7.83)	-	-
Duration of illness (month)	36.32 (6.51)	-	-
Handedness (R/M/L)	11/9/9	10/10/9	χ2 = 0.809, P = 0.35
HAMD-24	34.24 (4.59)	-	-

MDD: Patients with major depressive disorder; HC: Healthy controls; M: Male; F: Female; R: Right; M: Mixed; L: Left; HAMD: Hamilton Depression Rating Scale.

Table 2 Behavioral results, accuracy and reaction times, mean ± SD

Dual task	Task 2 expression	SOA	MDD	HC
Task 2 RTs1	Angry	500	1160 (250)	1020 (254)
	Angry	1000	1073 (227)	934 (212)
	Angry	1500	1037 (242)	905 (182)
	Happy	500	1054 (238)	973 (229)
	Happy	1000	938 (196)	889 (196)
	Happy	1500	909 (174)	852 (196)
	Neutral	500	1111 (220)	1018 (179)
	Neutral	1000	993 (158)	948 (177)
	Neutral	1500	962 (144)	936 (194)
Task 2 accuracy (%)2	Angry	500	80.3 (12.2)	88.1 (10.0)
	Angry	1000	81.3 (11.7)	88.1 (11.7)
	Angry	1500	81.6 (12.9)	89.2 (10.6)
	Happy	500	91.2 (7.3)	92.1 (7.7)
	Happy	1000	89.8 (6.9)	90.9 (8.8)
	Happy	1500	89.0 (8.2)	92.8 (10.2)
	Neutral	500	87.3 (8.2)	92.8 (8.0)
	Neutral	1000	88.3 (8.7)	93.3 (6.7)
	Neutral	1500	88.8 (6.4)	93.0 (6.5)

¹Reactive time presented in milliseconds (ms).

²Accuracy presented in percentage correct.

SOA: Stimulus onset asynchrony; MDD: Patients with major depressive disorder; HC: Healthy controls; RTs: Reaction times.

Table 3 Analysis of variances outcome of the behavioral data (dual task)

	Df (num)	Df (den)	F	P value	η2p
Dual task accuracy
Group	1	561	11.851	0.001	0.1751
Emotion	2	551	10.0961	< 0.001	0.2691
SOA	2	55	0.382	0.685	0.014
Group × emotion	2	55	1.664	0.199	0.057
Group × SOA	2	55	0.271	0.764	0.01
Emotion × SOA	4	53	0.89	0.477	0.063
Group × emotion × SOA	4	53	0.868	0.489	0.061
Dual task reaction time
Group	1	56	3.116	0.083	0.053
Emotion	2	551	12.6171	< 0.001	0.3141
SOA	2	551	101.331	< 0.001	0.6441
Group × emotion	2	55	2.601	0.083	0.086
Group × SOA	2	55	1.126	0.332	0.039
Emotion × SOA	4	53	0.464	0.751	0.008
Group × emotion × SOA	4	53	0.878	0.483	0.062

¹Represent that probability values were corrected for departures from compound symmetry using the Greenhouse-Geisser correction.

SOA: Stimulus onset asynchrony.

Table 4 The mean amplitude and latencies of event-related potential components

Variables1	MDD (n = 29)						HC (n = 29)
	Fz		Cz		Pz		Fz		Cz		Pz
	Amplitude	Latency	Amplitude	Latency	Amplitude	Latency	Amplitude	Latency	Amplitude	Latency	Amplitude	Latency
N100
500	-4.4 (3.1)	71.6 (14.3)	-2.5 (3.0)	61.4 (14.9)	-0.2 (2.5)	57.2 (22.9)	-5.3 (2.5)	73.7 (13.4)	-3.2 (2.0)	65.2 (14.8)	-0.6 (1.6)	55.2 (14.6)
1000	-4.5 (3.1)	70.6 (12.2)	-2.5 (2.8)	61.5 (13.8)	-0.2 (2.0)	58.9 (22.2)	-5.2 (2.5)	76.1 (16.5)	-3.1 (2.1)	64.7 (15.2)	-0.1 (2.3)	56.4 (20.5)
1500	-4.6 (2.9)	73.1 (14.5)	-2.6 (2.8)	62.9 (15.3)	-0.1 (2.3)	57.4 (19.5)	-5.2 (2.7)	74.3 (14.2)	-3.1 (2.3)	66.3 (15.7)	-0.5 (1.9)	57.7 (21.0)
P200
500	-4.4 (5.9)	178.6 (40.7)	-0.9 (4.9)	181.3 (41.7)	1.9 (4.0)	199.9 (47.2)	-4.0 (4.5)	173.0 (35.7)	-0.5 (3.5)	176.8 (37.0)	1.3 (2.7)	190.3 (45.9)
1000	-4.6 (6.1)	177.7 (41.8)	-1.1 (4.8)	179.0 (41.5)	1.7 (3.7)	204.5 (46.5)	-3.3 (4.6)	171.7 (32.5)	-0.2 (3.7)	178.0 (37.2)	1.6 (3.0)	186.7 (44.3)
1500	-4.5 (5.2)	178.3 (41.3)	-1.0 (4.5)	177.4 (38.9)	1.9 (3.7)	200.2 (46.3)	-3.5 (4.4)	177.7 (38.5)	0.1 (3.7)	186.7 (42.7)	1.7 (3.0)	192.3 (45.5)
P300
500	-7.1 (9.5)	278.8 (40.5)	-3.3 (6.3)	276.1 (42.4)	1.3 (4.7)	291.2 (51.4)	-9.6 (9.3)	274.6 (44.1)	-3.6 (6.2)	293.0 (57.4)	0.9 (4.9)	311.0 (59.0)
1000	-7.0 (9.4)	270.8 (34.2)	-3.3 (6.3)	282.6 (49.7)	1.3 (4.6)	295.5 (51.3)	-9.2 (9.7)	271.5 (42.3)	-3.5 (6.3)	293.0 (57.6)	1.0 (5.0)	302.6 (60.5)
1500	-7.3 (9.1)	277.2 (41.5)	-3.5 (6.2)	275.0 (43.5)	1.2 (4.6)	285.2 (47.6)	-9.6 (10.1)	265.4 (28.8)	-3.3 (6.5)	284.1 (54.1)	1.0 (5.0)	304.3 (54.7)
LPP
500	-9.3 (10.6)	435.8 (64.3)	-5.2 (6.6)	410.3 (52.9)	-0.3 (4.7)	405.1 (46.8)	-13.7 (11.5)	407.3 (56.5)	-5.8 (7.6)	419.8 (60.8)	-0.1 (5.8)	411.1 (53.3)
1000	-9.6 (10.8)	425.3 (60.6)	-5.3 (7.0)	412.8 (54.2)	-0.2 (4.9)	413.5 (53.2)	-14.0 (12.7)	413.6 (63.0)	-6.0 (8.0)	422.6 (57.3)	-0.3 (6.2)	423.4 (59.6)
1500	-9.5 (10.1)	423.0 (63.3)	-5.3 (6.8)	410.3 (55.2)	-0.2 (4.8)	409.2 (50.6)	-14.2 (11.8)	407.7 (58.1)	-5.7 (7.5)	425.8 (62.5)	-0.1 (5.4)	424.2 (61.8)
N100
Angry	-2.8 (2.6)	70.1 (16.3)	-1.7 (2.2)	61.9 (15.2)	0.1 (1.7)	59.0 (22.1)	-3.1 (2.2)	71.9 (14.8)	-2.0 (1.6)	63.2 (16.3)	-0.5 (1.3)	58.1 (20.1)
Happy	0.7 (2.7)	75.9 (24.0)	-0.5 (1.9)	66.6 (20.3)	0.3 (1.5)	65.4 (28.1)	-0.9 (2.5)	71.7 (21.6)	-0.9 (1.6)	66.3 (22.9)	-0.3 (1.2)	69.8 (30.7)
Neutral	-1.0 (2.4)	74.1 (23.7)	-1.0 (1.6)	72.8 (25.8)	-0.1 (1.2)	65.0 (28.1)	-1.0 (2.4)	68.7 (20.2)	-1.0 (1.4)	66.9 (23.2)	-0.6 (1.2)	65.9 (29.0)
P200
Angry	-1.9 (3.4)	179.1 (40.8)	0.2 (3.2)	185.0 (40.8)	2.0 (2.7)	214.0 (42.7)	-1.1 (2.6)	177.3 (34.6)	0.8 (2.3)	188.9 (40.3)	1.6 (1.9)	204.3 (42.4)
Happy	2.1 (3.2)	192.8 (27.1)	2.5 (2.9)	200.5 (32.4)	3.6 (2.4)	224.3 (30.0)	2.5 (3.6)	192.2 (23.2)	2.8 (2.7)	196.6 (23.0)	2.7 (2.0)	225.3 (27.3)
Neutral	1.8 (3.1)	194.7 (28.0)	2.0 (2.9)	196.9 (29.7)	3.2 (2.3)	222.0 (29.5)	2.3 (3.7)	194.6 (24.7)	2.4 (2.6)	201.3 (26.1)	2.3 (2.0)	221.7 (28.3)
P300
Angry	-3.7 (5.6)	274.1 (39.7)	-1.5 (4.1)	279.9 (47.2)	1.9 (3.1)	289.3 (49.3)	-5.2 (5.8)	276.6 (44.6)	-1.3 (4.0)	294.8 (58.5)	1.6 (3.4)	308.5 (58.6)
Happy	0.7 (4.1)	290.1 (57.9)	1.3 (3.9)	295.9 (62.3)	4.0 (2.7)	319.5 (61.6)	0.2 (3.7)	289.4 (50.6)	1.7 (3.2)	306.4 (58.3)	3.8 (3.5)	317.6 (51.2)
Neutral	0.4 (3.6)	292.5 (56.9)	1.0 (3.6)	301.2 (60.9)	3.9 (2.5)	324.9 (56.6)	-0.2 (3.7)	297.2 (59.9)	1.5 (3.1)	311.0 (63.1)	3.6 (3.0)	337.7 (51.8)
LPP
Angry	-5.3 (6.8)	423.0 (63.6)	-2.9 (4.6)	410.7 (56.2)	0.7 (3.3)	411.1 (57.3)	-8.6 (7.7)	404.4 (57.0)	-3.1 (5.2)	413.9 (59.8)	0.7 (4.0)	405.6 (54.6)
Happy	-0.1 (5.0)	440.7 (68.1)	0.7 (4.4)	445.3 (67.0)	3.1 (2.9)	416.9 (59.8)	-2.2 (4.5)	410.9 (60.9)	0.5 (3.4)	426.6 (71.0)	2.8 (3.2)	416.2 (66.5)
Neutral	0.0 (4.1)	450.3 (66.4)	0.7 (4.1)	441.8 (64.4)	3.3 (2.9)	424.7 (61.2)	-2.2 (4.3)	401.1 (49.8)	0.7 (3.7)	424.9 (66.6)	3.0 (3.4)	405.3 (52.0)

¹All values presented in microvolts (μV).

MDD: Patients with major depressive disorder; HC: Healthy controls; Fz: Frontal; Cz: Central; Pz: Parietal.

Table 5 Analysis of variances outcome of event-related potential mean amplitudes

	Df (num)	Df (den)	F	P value	η2p
Dual task: Task 2 N100
Group	1	56	0.637	0.428	0.011
Emotion	2	112	28.5031	< 0.001	0.3371
Electrode	2	112	39.2671	< 0.001	0.4121
Group × emotion	2	112	0.234	0.791	0.004
Group × electrode	2	112	0.909	0.406	0.016
Emotion × electrode	4	224	110.7951	< 0.001	0.6641
Group × emotion × electrode	4	224	0.688	0.601	0.012
Dual task: Task 2 P200
Group	1	56	0.024	0.877	0.000
Emotion	2	112	37.5591	< 0.001	0.4011
Electrode	2	112	29.2621	< 0.001	0.3431
Group × emotion	2	112	0.287	0.751	0.005
Group × electrode	2	112	5.9631	0.010	0.0961
Emotion × electrode	4	224	42.4771	< 0.001	0.4311
Group × emotion × electrode	4	224	0.092	0.888	0.002
Dual task: Task 2 P300
Group	1	56	0.104	0.748	0.002
Emotion	2	112	36.7951	< 0.001	0.3961
Electrode	2	112	125.8531	< 0.001	0.6921
Group × emotion	2	112	0.175	0.725	0.003
Group × electrode	2	112	2.615	0.094	0.045
Emotion × electrode	4	224	21.6391	< 0.001	0.2791
Group × emotion × electrode	4	224	0.703	0.467	0.012
Dual task: Task 2 LPP
Group	1	56	1.030	0.315	0.018
Emotion	2	112	55.4121	< 0.001	0.4971
Electrode	2	112	34.6301	< 0.001	0.7001
Group × emotion	2	112	0.098	0.830	0.002
Group × electrode	2	112	8.172	0.002	0.127
Emotion × electrode	4	224	32.1731	< 0.001	0.3651
Group × emotion × electrode	4	224	1.514	0.225	0.026

¹Represent that probability values were corrected for departures from compound symmetry using the Greenhouse-Geisser correction.

LPP: Late positive potential.

Table 6 Group differences between major depressive disorder and healthy controls in late positive potential amplitudes across electrodes

Electrode	Group	Mean	SE	P value	η2p
Fz	HC	-4.35	0.88	0.047	0.068
	MDD	-1.83
Cz	HC	-0.66	0.72	0.857	0.001
	MDD	-0.47
Pz	HC	2.15	0.57	0.777	0.001
	MDD	2.38

SE: Standard error; Fz: Frontal; Cz: Central; Pz: Parietal; HC: Healthy controls; MDD: Patients with major depressive disorder.