Newly developed waist actigraphy and its sleep/wake scoring algorithm

Minori Enomoto, Takuro Endo, Kazue Suenaga, Naoki Miura, Yasushi Nakano, Sayaka Kohtoh, Yujiro Taguchi, Sayaka Aritake, Shigekazu Higuchi, Masato Matsuura, Kiyohisa Takahashi, Kazuo Mishima*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


The purpose of this study was to formulate an algorithm for assessing sleep/waking from activity intensities measured with a waist-worn actigraphy, the Lifecorder PLUS (LC; Suzuken Co. Ltd., Nagoya, Japan), and to test the validity of the algorithm. The study consisted of 31 healthy subjects (M/F = 20/11, mean age 31.7years) who underwent one night of simultaneous measurement of activity intensity by LC and polysomnography (PSG). A sleep(S)/wake(W) scoring algorithm based on a linear model was determined through discriminant analysis of activity intensities measured by LC over a total of 235h and 56min and the corresponding PSG-based S/W data. The formulated S/W scoring algorithm was then used to score S/W during the monitoring epochs (2min each, 7078 epochs in total) for each subject. The mean agreement rate with the corresponding PSG-based S/W data was 86.9%, with a mean sensitivity (sleep detection) of 89.4% and mean specificity (wakefulness detection) of 58.2%. The agreement rates for the individual stages of sleep were 60.6% for Stage 1, 89.3% for Stage 2, 99.2% for Stage 3 + 4, and 90.1% for Stage REM. These results demonstrate that sleep/wake activity in young to middle-aged healthy subjects can be assessed with a reliability comparable to that of conventional actigraphy through LC waist actigraphy and the optimal S/W scoring algorithm.

Original languageEnglish
Pages (from-to)17-22
Number of pages6
JournalSleep and Biological Rhythms
Issue number1
Publication statusPublished - 2009
Externally publishedYes


  • Actigraphy
  • Polysomnography
  • Sleep-waking
  • Sleep/wakescoring algorithm
  • Waist-worn

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Neurology
  • Neuropsychology and Physiological Psychology


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