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dc.contributor.authorKlerman, Hadassa
dc.contributor.authorSt. Hilaire, Melissa A.
dc.contributor.authorGronfier, Claude
dc.contributor.authorSanthi, Nayantara
dc.contributor.authorKronauer, Richard E.
dc.contributor.authorGooley, Joshua James
dc.contributor.authorHull, Joseph Thomas
dc.contributor.authorLockley, Steven Ward
dc.contributor.authorWang, Wei
dc.contributor.authorKlerman, Elizabeth Beryl
dc.date.accessioned2012-12-21T18:45:53Z
dc.date.issued2012
dc.identifier.citationKlerman, Hadassa, Melissa A. St. Hilaire, Richard E. Kronauer, Joshua J. Gooley, Claude Gronfier, Joseph T. Hull, Steven W. Lockley, Nayantara Santhi, Wei Wang, and Elizabeth B. Klerman. 2012. Analysis method and experimental conditions affect computed circadian phase from melatonin data. PLoS ONE 7(4): e33836.en_US
dc.identifier.issn1932-6203en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:10121034
dc.description.abstractAccurate determination of circadian phase is necessary for research and clinical purposes because of the influence of the master circadian pacemaker on multiple physiologic functions. Melatonin is presently the most accurate marker of the activity of the human circadian pacemaker. Current methods of analyzing the plasma melatonin rhythm can be grouped into three categories: curve-fitting, threshold-based and physiologically-based linear differential equations. To determine which method provides the most accurate assessment of circadian phase, we compared the ability to fit the data and the variability of phase estimates for seventeen different markers of melatonin phase derived from these methodological categories. We used data from three experimental conditions under which circadian rhythms - and therefore calculated melatonin phase - were expected to remain constant or progress uniformly. Melatonin profiles from older subjects and subjects with lower melatonin amplitude were less likely to be fit by all analysis methods. When circadian drift over multiple study days was algebraically removed, there were no significant differences between analysis methods of melatonin onsets (P = 0.57), but there were significant differences between those of melatonin offsets (P<0.0001). For a subset of phase assessment methods, we also examined the effects of data loss on variability of phase estimates by systematically removing data in 2-hour segments. Data loss near onset of melatonin secretion differentially affected phase estimates from the methods, with some methods incorrectly assigning phases too early while other methods assigning phases too late; missing data at other times did not affect analyses of the melatonin profile. We conclude that melatonin data set characteristics, including amplitude and completeness of data collection, differentially affect the results depending on the melatonin analysis method used.en_US
dc.language.isoen_USen_US
dc.publisherPublic Library of Scienceen_US
dc.relation.isversionofdoi:10.1371/journal.pone.0033836en_US
dc.relation.hasversionhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3325223/pdf/en_US
dash.licenseLAA
dc.subjectbiologyen_US
dc.subjectanatomyen_US
dc.subjectphysiologyen_US
dc.subjectphysiological processesen_US
dc.subjectchronobiologyen_US
dc.subjectsleepen_US
dc.subjectcomputational biologyen_US
dc.subjectcomputer scienceen_US
dc.subjectcomputer modelingen_US
dc.subjectcomputerized simulationsen_US
dc.subjectmedicineen_US
dc.subjectclinical research designen_US
dc.subjectmeta-analysesen_US
dc.titleAnalysis Method and Experimental Conditions Affect Computed Circadian Phase from Melatonin Dataen_US
dc.typeJournal Articleen_US
dc.description.versionVersion of Recorden_US
dc.relation.journalPLoS ONEen_US
dash.depositing.authorKlerman, Elizabeth Beryl
dc.date.available2012-12-21T18:45:53Z
dc.identifier.doi10.1371/journal.pone.0033836*
dash.authorsorderedfalse
dash.contributor.affiliatedKronauer, Richard
dash.contributor.affiliatedHull, Joseph Thomas
dash.contributor.affiliatedGooley, Joshua James
dash.contributor.affiliatedLockley, Steven
dash.contributor.affiliatedWang, Wei
dash.contributor.affiliatedKlerman, Elizabeth


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