Table II.

Comparisons of sleep structures between the three groups.

Group	NREM phase 1 (min)	NREM phase 2 (min)	NREM phase 3 (min)	NREM phase 4 (min)	REM (min)
ECO	23.94±13.27	260.02±30.71	47.00±16.57	73.88±13.31	126.19±35.01
E-AED I	29.50±10.61	260.02±30.71	42.79±6.27	70.48±9.62	116.99±12.90
E-AED II	92.10±48.24	240.96±42.92	51.19±8.75	70.96±24.90	70.82±17.69
P-value	<0.01	>0.05	>0.05	>0.05	<0.01

Data are expressed as the mean ± SD. E-AED I, duration of VPA administration <3 months; E-AED II, duration of VPA administration >3 months; ECO, without VPA; VPA, sodium valproate; NREM, non-rapid eye movement; REM, rapid eye movement.