Table 2. Statistical comparisons of power spectral density in different brain regions between groups.

PSD	Healthy Controls (N = 15)		Patients (N = 15)		Mann-Whitney U test
	Mean	SD	Mean	SD	P value
LPMC
Low-frequency band*	5.85	2.61	2.11	1.00	P = 1. 00×10−3
Middle-frequency band**	7.26	1.81	2.60	0.46	P = 2. 86×10−10
High-frequency band**	4.34	0.69	1.88	0.28	P = 1. 33×10−9
RPMC
Low-frequency band*	6.45	2.83	2.69	1.15	P = 1. 00×10−3
Middle-frequency band**	6.78	1.48	2.75	0.67	P = 2. 87×10−10
High-frequency band**	4.68	0.86	2.11	0.43	P = 1. 50×10−9
SMA
Low-frequency band*	4.97	2.21	2.53	1.07	P = 2. 00×10−3
Middle-frequency band**	5.78	1.25	3.04	0.39	P = 4. 47×10−10
High-frequency band**	4.21	0.67	2.31	0.38	P = 1. 33×10−9

*implies significant group difference at P<0.05;

**implies significant group difference at P<0.001. PSD, power spectral density; SD, standard deviation; LPMC, left primary motor cortex; RPMC, right motor cortex; SMA, supplementary motor area. Group-differences were tested using SPSS software.