02711nas a2200325   4500008004100000022001400041245008600055210006900141260001300210300001100223490000700234520179000241653001902031653002402050653001102074653002402085653002002109653001602129653002602145653001702171653001502188653001702203100002102220700002602241700002002267700001902287700002102306700002202327856003602349       2012                        eng d  a1365-286900aProbabilistic sleep architecture models in patients with and without sleep apnea.0 aProbabilistic sleep architecture models in patients with and wit  c2012 Jun  a330-410 v213 a<p>Sleep fragmentation of any cause is disruptive to the rejuvenating value of sleep. However, methods to quantify sleep architecture remain limited. We have previously shown that human sleep-wake stage distributions exhibit multi-exponential dynamics, which are fragmented by obstructive sleep apnea (OSA), suggesting that Markov models may be a useful method to quantify architecture in health and disease. Sleep stage data were obtained from two subsets of the Sleep Heart Health Study database: control subjects with no medications, no OSA, no medical co-morbidities and no sleepiness (n = 374); and subjects with severe OSA (n = 338). Sleep architecture was simplified into three stages: wake after sleep onset (WASO); non-rapid eye movement (NREM) sleep; and rapid eye movement (REM) sleep. The connectivity and transition rates among eight 'generator' states of a first-order continuous-time Markov model were inferred from the observed ('phenotypic') distributions: three exponentials each of NREM sleep and WASO; and two exponentials of REM sleep. Ultradian REM cycling was accomplished by imposing time-variation to REM state entry rates. Fragmentation in subjects with severe OSA involved faster transition probabilities as well as additional state transition paths within the model. The Markov models exhibit two important features of human sleep architecture: multi-exponential stage dynamics (accounting for observed bout distributions); and probabilistic transitions (an inherent source of variability). In addition, the model quantifies the fragmentation associated with severe OSA. Markov sleep models may prove important for quantifying sleep disruption to provide objective metrics to correlate with endpoints ranging from sleepiness to cardiovascular morbidity.</p>10aCohort Studies10aComputer Simulation10aHumans10aModels, Theoretical10aPolysomnography10aProbability10aSleep Apnea Syndromes10aSleep Stages10aSleep, REM10aTime Factors1 aBianchi, Matt, T1 aEiseman, Nathaniel, A1 aCash, Sydney, S1 aMietus, Joseph1 aPeng, Chung-Kang1 aThomas, Robert, J  uhttps://chs-nhlbi.org/node/1542