Table 3.

The mean amplitude of N270 for the two groups in each of the four conditions and at each of the chosen electrodes (mean ± SD)

Amplitude (μV)	Match	Task-irrelevant mismatch	Task-relevant mismatch	Conjunction mismatches
Controls
F3	1.69±2.87	0.48±1.98a	−0.46±1.92a	−0.73±2.11a
F4	2.93±3.85	1.01±2.60a	0.19±1.62a	−0.71±1.94a,b,c
C3	0.96±2.91	−0.61±1.58a	−0.48±1.43	−1.54±1.42a,c
C4	2.81±3.49	0.39±3.14a	−0.32±1.66a	−0.31±2.78a
GAD
F3	2.32±2.31	0.34±2.28a	1.33±1.73d	1.12±1.63a,d
F4	1.93±2.44	0.91±1.74a	0.48±1.97a	0.56±2.15a
C3	1.39±2.94	0.45±2.80	−0.18±1.70a	0.30±2.07d
C4	1.56±2.72	0.83±1.80	0.34±1.44	0.48±2.37

Notes:

^aSignificantly different from the match condition in each group (P<0.05).

^bSignificantly different from the task-irrelevant mismatch condition in each group (P<0.05).

^cSignificantly different from the task-relevant mismatch condition in each group (P<0.05).

^dSignificantly different from the control group (P<0.01). Controls are healthy subjects.

Abbreviations: SD, standard deviation; GAD, generalized anxiety disorder.