Table 2.

Factor loadings (Varimax normalized) and eigen values for Ten-item Sleepiness Questionnaires and modified Epworth Sleepiness Scale (mESS)*

	Ten-item Sleepiness Questionnaires				mESS
	Normal subjects (n = 117)		Patients (n = 122)		Normal subjects (n = 117)		Patients (n = 122)
Item number	Factor 1	Factor 2	Factor 1	Factor 2	Factor 1	Factor 2	Factor 1
Item1	0.54	0.18	0.77	0.09	0.55	0.33	0.79
Item2	0.60	0.06	0.75	0.04	0.57	0.01	0.76
Item3	0.67	0.25	0.81	0.12	0.74	0.14	0.81
Item4	0.55	0.04	0.61	0.12	0.60	0.10	0.64
Item5	0.16	0.44	0.63	0.58	0.05	0.56	0.68
Item6	0.13	0.40	0.69	0.10	0.09	0.33	0.65
Item7	0.17	0.64	0.67	0.35	0.18	0.71	0.69
Item8	0.01	0.54	0.33	0.79
Item9	0.52	0.27	0.67	0.23
Item10	0.09	0.63	0.71	0.18	0.08	0.65	0.69
Eigen valuea	1.89	1.48	4.57	1.20	1.66	1.40	4.11

* mESS is the composition of items 1, 2, 3, 4, 5, 6, 7, and 10 from Ten-item Sleepiness Questionnaire

^aOnly eigen values > 1 are shown