Document Detail


Estimation of Human Circadian Phase via a Multi-Channel Ambulatory Monitoring System and a Multiple Regression Model.
MedLine Citation:
PMID:  21252366     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Reliable detection of circadian phase in humans using noninvasive ambulatory measurements in real-life conditions is challenging and still an unsolved problem. The masking effects of everyday behavior and environmental input such as physical activity and light on the measured variables need to be considered critically. Here, we aimed at developing techniques for estimating circadian phase with the lowest subject burden possible, that is, without the need of constant routine (CR) laboratory conditions or without measuring the standard circadian markers, (rectal) core body temperature (CBT), and melatonin levels. In this validation study, subjects (N = 16) wore multi-channel ambulatory monitoring devices and went about their daily routine for 1 week. The devices measured a large number of physiological, behavioral, and environmental variables, including CBT, skin temperatures, cardiovascular and respiratory function, movement/posture, ambient temperature, and the spectral composition and intensity of light received at eye level. Sleep diaries were logged electronically. After the ambulatory phase, subjects underwent a 32-h CR procedure in the laboratory for measuring unmasked circadian phase based on the "midpoint" of the salivary melatonin profile. To overcome the complex masking effects of confounding variables during ambulatory measurements, multiple regression techniques were applied in combination with the cross-validation approach to subject-independent prediction of circadian phase. The most accurate estimate of circadian phase was achieved using skin temperatures, irradiance for ambient light in the blue spectral band, and motion acceleration as predictors with lags of up to 24 h. Multiple regression showed statistically significant improvement of variance of prediction error over the traditional approaches to determining circadian phase based on single predictors (motion acceleration or sleep log), although CBT was intentionally not included as the predictor. Compared to CBT alone, our method resulted in a 40% smaller range of prediction errors and a nonsignificant reduction of error variance. The proposed noninvasive measurement method could find applications in sleep medicine or in other domains where knowing the exact endogenous circadian phase is important (e.g., for the timing of light therapy).
Authors:
Vitaliy Kolodyazhniy; Jakub Späti; Sylvia Frey; Thomas Götz; Anna Wirz-Justice; Kurt Kräuchi; Christian Cajochen; Frank H Wilhelm
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of biological rhythms     Volume:  26     ISSN:  1552-4531     ISO Abbreviation:  J. Biol. Rhythms     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8700115     Medline TA:  J Biol Rhythms     Country:  United States    
Other Details:
Languages:  eng     Pagination:  55-67     Citation Subset:  IM    
Affiliation:
Department of Clinical Psychology and Psychotherapy, Faculty for Psychology, University of Basel, Basel, Switzerland. kolodyazhniy@gmx.net.
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