Abstract: Increased activity of the sympathetic nervous system (SNS) as measured by catecholamine blood levels, muscle sympathetic nerve activity or heart rate variability (HRV) has been frequently reported in patients with obstructive sleep apnea (OSA).
The significance of this finding has been a topic of an ongoing and controversial debate because cardiovascular co-morbidities that are frequent among these patients (hypertension, ischemic heart disease, cerebro-vascular incidents) can also cause a disbalance in the autonomic nervous system. Recent reports that continuous positive airway pressure (CPAP) therapy reduces the activity of the SNS have lent support to the hypothesis that OSA alone can cause a sustained sympathetic hyper-activation, and also pointed to a simple and inexpensive yet powerful method for assessment of impacts of an OSA treatment to the vegetative nervous system and more importantly, to cardio-vascular health.
The use of CPAP in treating OSA is limited by patient non-compliance due to the side effects (unpleasant mucosal dryness, nasal congestion, rhinorhea or sneezing) that result from an irritation of the upper airways. Poor compliance is most frequently encountered among mild and moderate apneacs, who may often find the side effects more troublesome than the OSA symptoms. Alternative treatment modalities are therefore needed for such patients, as well as for patients with clearly reversible anatomical abnormalities. The most frequently used alternative is mandibular advancement devices - MAD (sometimes referred to as mandibular repositioning appliance â€“ MRA), although surgical and pharmacological options are also available.
Popovic D, J. R., Morgan T, et al (2008). "Effect of treatment with mandibular advancing device (MAD) on autonomic nervous system activity as measured by Heart Rate Variability (HRV)." Sleep: 31: A153.