Ambulatory estimation of human circadian phase using models of varying complexity based on non-invasive signal modalities

Enrique A Gil, Xavier L Aubert*, Domien G M Beersma

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    6 Citations (Scopus)


    In this work, we introduce a number of models for human circadian phase estimation in ambulatory conditions using various sensor modalities. Machine learning techniques have been applied to ambulatory recordings of wrist actigraphy, light exposure, electrocardiograms (ECG), and distal and proximal skin temperature to develop ARMAX models capturing the main signal dependencies on circadian phase and evaluating them versus melatonin onset times. The most accurate models extracted heart rate variability features from an ECG coupled with wrist activity information to produce phase estimations with prediction errors of ~30 minutes. Replacing the ECG features with skin temperature from the upper leg led to a slight degradation, while less accurate results, in the order of 1 hour, were obtained from wrist activity and light measurements. The trade-off between highest precision and least obtrusive configuration is discussed for applications to sleep and mood disorders caused by a misalignment of the internal phase with the external solar and social times.

    Original languageEnglish
    Title of host publication Engineering in Medicine and Biology Society (EMBC)
    Subtitle of host publication36th Annual International Conference of the IEEE
    Number of pages4
    ISBN (Electronic)978-1-4244-7929-0
    ISBN (Print)1557-170X
    Publication statusPublished - Aug-2014
    Event36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society EMBC 2014 - Chicago, IL, United States
    Duration: 26-Aug-201430-Aug-2014


    Conference36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society EMBC 2014
    Country/TerritoryUnited States
    CityChicago, IL

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