Title :
Time-varying analysis of autonomic control during arousal from sleep in obstructive sleep apnea syndrome
Author :
Blasi, A. ; Jo, J. ; Valladares, E. ; Juarez, R. ; Baydur, A. ; Khoo, M.C.K.
Author_Institution :
Dept. of Biomed. Eng., Southern California Univ., Los Angeles, CA, USA
Abstract :
Patients with obstructive sleep apnea syndrome (OSAS) have elevated sympathetic drive and impaired parasympathetic cardiac control during wakefulness and sleep. Previous studies have demonstrated that sympathetic overactivity in OSAS can lead to impaired peripheral vasodilatory responses to hypoxia. The present study was conducted to determine whether the autonomic response to arousal from sleep is also altered in OSAS. In 8 OSAS and 8 normal controls, we performed time-varying spectral analyses of cardiovascular and respiratory variability following acoustically-induced arousal from sleep. In all subjects and in both REM and non-REM sleep, the arousal responses of the spectral parameters representing vagal heart-rate modulation were small or non-existent after accounting for the accompanying changes in respiration. In non-REM sleep, the OSAS subjects showed substantially attenuated cardiac sympathetic responses to arousal but the peripheral vascular response was preserved. In REM sleep, the sympathetic cardiovascular responses to arousal were similar in both subject groups, but these responses were much smaller than those exhibited by normals in non-REM sleep. Our results suggest that OSAS leads primarily to an impairment of the cardiac sympathoexcitatory reaction to arousal from non-REM sleep; however, the normal autonomic cardiovascular response to arousal in REM sleep appears to be preserved.
Keywords :
biocontrol; blood pressure measurement; cardiovascular system; electrocardiography; medical signal processing; patient monitoring; pneumodynamics; sleep; spectral analysis; arousal from sleep; autonomic control; autonomic response; cardiac sympathoexcitatory reaction; cardiovascular variability; continuous blood pressure; obstructive sleep apnea syndrome; respiratory variability; spectral analyses; sympathetic cardiovascular responses; time-varying analysis; vagal heart-rate modulation; Autonomic nervous system; Biomedical engineering; Cardiology; Cardiovascular diseases; Control systems; Heart rate variability; Hypertension; Signal processing algorithms; Sleep apnea; Spectral analysis;
Conference_Titel :
Engineering in Medicine and Biology Society, 2003. Proceedings of the 25th Annual International Conference of the IEEE
Print_ISBN :
0-7803-7789-3
DOI :
10.1109/IEMBS.2003.1279647