Table 4.

Results Derived from Period Amplitude Analysis of the Electroencephalogram During Non-Rapid Eye Movement Sleep in 9 Women with Severe PMS and 12 Asymptomatic Women (Control Subjects) in the Mid-Follicular and Late Luteal Phases of Their Menstrual Cycles.

Variable	Group	Menstrual Cycle Phase
		Follicular	Late Luteal
Delta average sample amplitude, μV	Control	15.6 (2.0)	15.7 (2.1)
	PMS	17.3 (2.7)	17.4 (2.9)
Delta incidence, sec	Control	25.0 (2.9)	24.6 (3.2)*
	PMS	21.6 (2.6)#	21.4 (2.3)*#
Theta average sample amplitude, μV	Control	6.9 (1.1)	7.3 (1.4)*
	PMS	8.9 (1.1)#	9.1 (1.3)*#
Theta incidence, sec	Control	2.0 (1.9)	2.0 (1.9)
	PMS	4.0 (1.7)#	4.0 (1.6)#
Alpha derivative average sample amplitude, μV	Control	6.7 (1.1)	7.0 (1.3)*
	PMS	6.9 (0.5)	7.1 (0.6)*
Alpha incidence, sec	Control	5.7 (1.0)	5.6 (1.2)
	PMS	5.9 (0.9)	5.6 (0.5)
Sigma derivative average sample amplitude, μV	Control	5.8 (0.8)	6.1 (0.9)*
	PMS	6.2 (0.7)	6.4 (0.8)*
Sigma incidence, sec	Control	2.3 (0.4)	2.7 (0.5)*
	PMS	2.7 (0.8)	3.0 (0.9)*
Beta1 derivative average sample amplitude, μV	Control	3.7 (0.4)	4.0 (0.5)*
	PMS	3.9 (0.3)	4.0 (0.5)*
Beta1 incidence, sec	Control	2.1 (0.4)	2.5 (0.5)*
	PMS	2.3 (0.5)	2.5 (0.6)*

Data are expressed as mean (SD). PMS refers to premenstrual syndrome.

^*Significantly different from follicular phase (P < 0.05)

^#Significantly different from controls (P < 0.05). See text for details.