Development of a technique for capturing sleep Predictor signals during wakefulness

E. Fujita, Y. Ogura, N. Ochiai, K. Murata*, T. Kamei, Y. Ueno, S. Kaneko

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The feature of sleep pattern is determined by the circadian rhythm that is typified by the rhythm of body temperature and homeostasis. In this study, a method was conceived for capturing changes in the peripheral circulatory system during the process of lowering of core body temperature via finger plethysmogram. Recorded signals were then analyzed by chaos analysis. By analyzing the variations in the time series of the gradients of the largest Lyapunov exponent and the power value (the square of the finger plethysmogram amplitude), and by observing the conditions of the subject, the phenomenon that predicts the subject's transition to Stage 1 sleep during wakefulness was detected. These predictive signals for falling asleep can be found when the amplitude of the power gradient was in transition, and when the largest Lyapunov exponent's gradient and the power gradient have an inverse phase with 180 degrees.

Original languageEnglish
Pages (from-to)1251-1256
Number of pages6
JournalJournal of Optoelectronics and Advanced Materials
Issue number5
Publication statusPublished - 2008 May
Externally publishedYes


  • Circadian rhythm
  • Sleep pattern
  • Sleep prediction signal

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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