Research Study Abstract

Can an automated sleep detection algorithm for waist-worn accelerometry replace sleep logs?

  • Published on Apr 2018

Abstract: The purpose of this study was to test whether estimates of bedtime, wake time, and sleep period time (SPT) were comparable between an automated algorithm (ALG) applied to waist-worn accelerometry data and a sleep log (LOG) in an adult sample. A total of 104 participants were asked to log evening bedtime and morning wake time and wear an ActiGraph wGT3X-BT accelerometer at their waist for 24 h/day for 7 consecutive days. Mean difference and mean absolute difference (MAD) were computed. Pearson correlations and dependent-sample t tests were used to compare LOG-based and ALG-based sleep variables. Effect sizes were calculated for variables with significant mean differences. A total of 84 participants provided 2+ days of valid accelerometer and LOG data for a total of 368 days. There was no mean difference (p = 0.47) between LOG 472 ± 59 min and ALG SPT 475 ± 66 min (MAD = 31 ± 23 min, r = 0.81). There was no significant mean difference between bedtime (2348 h and 2353 h for LOG and ALG, respectively; p = 0.14, MAD = 25 ± 21 min, r = 0.92). However, there was a significant mean difference between LOG (0741 h) and ALG (0749 h) wake times (p = 0.01, d = 0.11, MAD = 24 ± 21 min, r = 0.92). The LOG and ALG data were highly correlated and relatively small differences were present. The significant mean difference in wake time might not be practically meaningful (Cohen’s d = 0.11), making the ALG useful for sample estimates. MAD, which gives a better estimate of the expected differences at the individual level, also demonstrated good evidence supporting ALG individual estimates.


  • Tiago V. Barreira 1
  • Jessica G. Redmond 2
  • Tom D. Brutsaert 1
  • John M. Schuna Jr. 3
  • Emily F. Mire 4
  • Peter T. Katzmarzyk 4
  • Catrine Tudor-Locke 5


  • 1

    School of Education, Syracuse University, 820 Comstock Ave., Syracuse, NY 13244, USA.

  • 2

    Biology Department, Utica College, 1600 Burrstone Rd., Utica, NY 13505, USA.

  • 3

    College of Public Health and Human Sciences, Oregon State University, 1500 SW Jefferson St., Corvallis, OR 97331, USA.

  • 4

    Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, USA.

  • 5

    Department of Kinesiology, University of Massachusetts Amherst, 30 Eastman Ln., Amherst, MA 01002, USA.


Canadian Science Publishing