Table 4.

Subjective estimation of sleep quality and sleep duration using the St. Mary's Sleep Questionnaire, stratified according to severity of sleep disordered breathing

Parameter	AHI < 5	5 ≤ AHI < 15	15 ≤ AHI < 30	AHI ≥ 30	P valuea
Sleep onset, h min	22h06 to 5h12	21h18 to 6h06	21h18 to 5h56	21h18 to 6h00	NS
Sleep depthb	4.7 ± 1.7	4.7 ± 1.6	4.7 ± 1.7	4.9 ± 1.6	NS
Estimated sleep duration, h
Nocturnal	6.9 ± 1.4	7.0 ± 1.8	6.6 ± 1.7	7.0 ± 1.6	0.04
Diurnal	0.2 ± 0.7	0.1 ± 0.2	0.2 ± 0.7	0.3 ± 0.7	0.0006
Wake sensationc	4.1 ± 1.0	4.1 ± 1.0	4.0 ± 1.0	4.2 ± 0.9	0.03
Sleep qualityc	4.1 ± 1.0	4.1 ± 1.0	4.0 ± 1.2	4.2 ± 1.1	NS
Satisfied sleepd	3.5 ± 1.3	3.5 ± 1.2	3.5 ± 1.3	3.6 ± 1.2	NS
Sleep latency, h	0.5 ± 0.5	0.6 ± 1.4	0.7 ± 2.2	0.5 ± 0.6	NS

Data are presented as mean ± SD.

^aP values were derived using the Kruskall-Wallis test.

^bMaximum score of 8.

^cMaximum score of 6.

^dMaximum score of 5.