Obstructive sleep apnea (OSA) is a common medical disorder of increasing interest in the medical community because of evidence that significant cardiovascular and neurocognitive defects occur when OSA is untreated or inadequately treated. Positive airway pressure (PAP) therapy remains the most effective and widely prescribed treatment for OSA. However, long-term adherence to PAP therapy has proven challenging. Alternative surgical and medical therapies are available, but an estimation of treatment efficacy based on clinical grounds has yielded inconsistent and largely disappointing results. The identification of a unique mechanism for OSA in a given clinical subject should prove useful in the selection of treatment alternatives to PAP. Until recently, personalizing treatment of OSA based on the determination of the mechanism of action was available only in experimental settings requiring invasive instrumentation. However, it is now possible to analyze clinical polysomnography data and identify the physiologic mechanism(s) or phenotype(s) of OSA in an individual case. The determination of physiologic phenotype offers the opportunity for personalized therapy. Additionally, physiologic phenotyping of OSA provides an opportunity to understand OSA mechanisms in specific subgroups, such as the elderly and the obese without OSA. In this manuscript, we introduce the reader to the concept and techniques of physiologic phenotyping of OSA and summarize the scientific data that physiologic phenotyping confers to understanding and treating OSA.
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