Table 2.

Sleep characteristics of normal subjects and patients with sleep apnea-hypopnea syndrome across entire night and across first three NREM-REM cycles

Normal ControlModerate-to-Severe SAHSSevere SAHS
Variables for entire night
Sleep efficiency, %88.4 (4.7)83.1 (8.0)86.2 (5.6)
TIB, min477 (51)449 (44)451 (53)
TST, min422 (51)373 (47)390 (61)
NREM duration, min326 (53)302 (26)327 (47)
REM duration, min95 (21)71 (25)64 (26)
No. of nocturnal awakenings45.6 (13.1)54.6 (25.0)58.2 (43.8)
No. of sleep changes231.8 (74.2)232.1 (66.8)292.4 (117.3)
Variables for first three NREM-REM cycles
NREM duration, min208 (38)211 (37)245 (25)*
Light sleep duration, min186 (34)199 (32)231 (34)*
Slow-wave sleep duration, min22 (16)12 (12)15 (17)
REM duration, min57 (24)52 (22)56 (25)
Awake duration, min14 (8)29 (16)26 (20)
  • Values are means (SD). Comparisons were performed with normal control subjects. TIB, time in bed; TST, total sleep time; NREM, non-rapid eye movements; REM, rapid eye movements.

  • * P < 0.01.