Modifications of cyclic alternating pattern in sleep apnea syndrome.
Within non-rapid eye movement sleep, two complementary modalities of arousal organization may be identified: (1) the cyclic alternating pattern (CAP), correlated with successive upward (phase A) and downward (phase B) fluctuations of arousal and arousal-related vegetative functions, and (2) non-CAP, corresponding to a relative stability of arousal and vegetative activities. In a 62-year-old overweight and heavily snoring man, complaining of excessive daytime sleepiness, three consecutive polysomnograms displayed a highly frequent occurrence of nocturnal apneas (apnea index: 15), mostly obstructive and mixed, limited to non-rapid eye movement sleep stages 1 and 2. The apneic episodes, that never occurred during non-CAP, exclusively appeared during the inhibitory phase B of CAP, whereas the following breathing resumption was mainly induced by an activating phase A pattern. The crucial effect of arousal instability on respiratory control is emphasized.
Department of Neurology, University of Parma, Italy.
M G
MG
Terzano
L
L
Parrino
M C
MC
Spaggiari
D000328:Adult; D001143:Arousal / Q000502:physiology; D004569:Electroencephalography; D006801:Humans; D008297:Male; D012891:Sleep Apnea Syndromes / Q000503:physiopathology*; D012895:Sleep, REM / Q000502:physiology