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This Article Full Text Full Text (PDF) All Versions of this Article: 291/4/R1165    most recent 00787.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Jurysta, F. Articles by Linkowski, P. Search for Related Content PubMed PubMed Citation Articles by Jurysta, F. Articles by Linkowski, P.

SLEEP AND TEMPERATURE REGULATION

The link between cardiac autonomic activity and sleep delta power is altered in men with sleep apnea-hypopnea syndrome

¹Sleep Laboratory, Department of Psychiatry, ²Department of Cardiology and Hypertension Clinic, Erasmus Academic Hospital of Free University of Brussels, and ³Biomedical Physics Laboratory, Free University of Brussels, Brussels; and ⁴Experimental Physics Laboratory, Université de Mons-Hainaut, Mons, Belgium

Submitted 7 November 2005 ; accepted in final form 29 April 2006

We hypothesize that sleep apnea-hypopnea alters interaction between cardiac vagal modulation and sleep delta EEG. Sleep apnea-hypopnea syndrome (SAHS) is related to cardiovascular complications in men. SAHS patients show higher sympathetic activity than normal subjects. In healthy men, non-rapid eye movement (NREM) sleep is associated with cardiac vagal influence, whereas rapid eye movement (REM) sleep is linked to cardiac sympathetic activity. Interaction between cardiac autonomic modulation and delta sleep EEG is not altered across a life span nor is the delay between appearances of modifications in both signals. Healthy controls, moderate SAHS, and severe SAHS patients were compared across the first three NREM-REM cycles. Spectral analysis was applied to ECG and EEG signals. High frequency (HF) and low frequency (LF) of heart rate variability (HRV), ratio of LF/HF, and normalized (nu) delta power were obtained. A coherency analysis between HF_nu and delta was performed, as well as a correlation analysis between obstructive apnea index (AI) or hypopnea index (HI) and gain, coherence, or phase shift. HRV components were similar between groups. In each group, HF_nu was larger during NREM, while LF_nu predominated across REM and wake stages. Coherence and gain between HF_nu and delta decreased from controls to severe SAHS patients. In SAHS patients, the delay between modifications in HF_nu and delta did not differ from zero. AI and HI correlated negatively with coherence, while HI correlated negatively with gain only. Apneas-hypopneas affect the link between cardiac sympathetic and vagal modulation and delta EEG demonstrated by the loss of cardiac autonomic activity fluctuations across shifts in sleep stages. Obstructive apneas and hypopneas alter the interaction between both signals differently.

heart rate variability; delta sleep electroencephalogram; loss of fluctuations; phase shift