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Updated: Jun 21, 2026
Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children
Published on: April 29, 2013
Model-based assessment of cardiovascular autonomic control in children with obstructive sleep apnea
Jarree Chaicharn1, Zheng Lin, Maida L Chen
1Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089-1111, USA.
Insights
Pediatric obstructive sleep apnea syndrome (OSAS) is linked to higher sympathetic activity and reduced autonomic responses. Vagal control appears normal, but overall cardiovascular autonomic control is impaired in children with OSAS.
Area of Science:
- Cardiovascular physiology
- Autonomic nervous system function
- Pediatric sleep medicine
Background:
- Obstructive sleep apnea syndrome (OSAS) is a prevalent condition in children.
- The impact of OSAS on daytime autonomic cardiovascular control in pediatric populations requires further elucidation.
- Understanding autonomic dysfunction in pediatric OSAS is crucial for managing associated health risks.
Purpose of the Study:
- To quantitatively assess daytime autonomic cardiovascular control in pediatric subjects with and without obstructive sleep apnea syndrome (OSAS).
- To investigate the specific components of autonomic control, including vagal and sympathetic activity, and baroreflex function.
Main Methods:
- Monitoring of respiration, R-R intervals, and continuous blood pressure in awake pediatric subjects.
- Assessment in supine and standing postures, and during cold face stimulation.
- Utilizing spectral analysis of heart rate variability and a closed-loop minimal model to partition autonomic components.
Main Results:
- Subjects with OSAS showed a lower ratio of low- to high-frequency power in heart rate variability compared to controls.
- Baroreflex gain was reduced in subjects with OSAS.
- Autonomic responses to orthostatic stress and cold face stimulation were blunted in children with OSAS.
Conclusions:
- Pediatric OSAS is associated with elevated baseline cardiovascular sympathetic activity.
- Vagal modulation of the heart remains relatively preserved in pediatric OSAS.
- Autonomic reactivity to physiological challenges is impaired in children with OSAS, suggesting a significant impact on cardiovascular regulation.
Study Objectives:
To quantitatively assess daytime autonomic cardiovascular control in pediatric subjects with and without obstructive sleep apnea syndrome (OSAS).
Design:
Respiration, R-R intervals, and noninvasive continuous blood pressure were monitored in awake subjects in the supine and standing postures, as well as during cold face stimulation.
Setting:
Sleep disorders laboratory in a hospital setting.
Participants:
Ten pediatric patients (age 11.4 +/- 3.6 years) with moderate to severe OSAS (obstructive apnea-hypopnea index = 21.0 +/- 6.6/1 h) before treatment and 10 age-matched normal control subjects (age 11.5 +/- 3.7 years).
Measurements And Results:
Spectral analysis of heart rate variability revealed that high-frequency power was similar and the ratio of low- to high-frequency power was lower in subjects with OSAS vs control subjects. The closed-loop minimal model allowed heart rate variability to be partitioned into a component mediated by respiratory-cardiac coupling and a baroreflex component, whereas blood pressure variability was assumed to result from the direct effects of respiration and fluctuations in cardiac output. Baroreflex gain was lower in subjects with OSAS vs control subjects. Under orthostatic stress, respiratory-cardiac coupling gain decreased in both subject groups, but baroreflex gain decreased only in controls. The model was extended to incorporate time-varying parameter changes for analysis of the data collected during cold face stimulation: cardiac output gain increased in controls but remained unchanged in OSAS.
Conclusions:
Our findings suggest that vagal modulation of the heart remains relatively normal in pediatric subjects with OSAS. However, baseline cardiovascular sympathetic activity is elevated, and reactivity to autonomic challenges is impaired.
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