Registration of 24-hour accelerometric rest-activity profiles and its application to human chronotypes

Erin I. McDonnell, Vadim Zipunnikov, Jennifer A. Schrack, Jeff Goldsmith, Julia Wrobel

Research output: Contribution to journalArticlepeer-review


By collecting data continuously over 24 hours, accelerometers and other wearable devices can provide novel insights into circadian rhythms and their relationship to human health. Existing approaches for analyzing diurnal patterns using these data, including the cosinor model and functional principal component analysis, have revealed and quantified population-level diurnal patterns, but considerable subject-level variability remained uncaptured in features such as wake/sleep times and activity intensity. This remaining informative variability could provide a better understanding of chronotypes, or behavioral manifestations of one’s underlying 24-hour rhythm. Curve registration, or alignment, is a technique in functional data analysis that separates “vertical” variability in activity intensity from “horizontal” variability in time-dependent markers like wake and sleep times; this data-driven approach is well-suited to studying chronotypes using accelerometer data. We develop a parametric registration framework for 24-hour accelerometric rest-activity profiles represented as dichotomized into epoch-level states of activity or rest. Specifically, we estimate subject-specific piecewise linear time-warping functions parametrized with a small set of parameters. We apply this method to data from the Baltimore Longitudinal Study of Aging and illustrate how estimated parameters give a more flexible quantification of chronotypes compared to traditional approaches.

Original languageEnglish (US)
Pages (from-to)1299-1319
Number of pages21
JournalBiological Rhythm Research
Issue number8
StatePublished - 2022


  • Accelerometer
  • cosinor model
  • data-driven chronotypes
  • diurnal registration
  • functional principal components analysis

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Physiology (medical)


Dive into the research topics of 'Registration of 24-hour accelerometric rest-activity profiles and its application to human chronotypes'. Together they form a unique fingerprint.

Cite this