title: Investigating the interaction between heart rate variability and sleep EEG using nonlinear algorithms.
abstract: BACKGROUND
  The multi-mode modulation is a key feature of sleep EEG. And the short-term fractal property reflects the sympathovagal modulation of heart rate variability (HRV). The properties of EEG and HRV strongly correlated with sleep status and are interesting in clinic diagnosis.
  
  
  METHODS
  19 healthy female subjects were included for over-night standard polysomnographic study. Hilbert Huang transform (HHT) was used to characterize the temporal features of slow- and fast-wave oscillations decomposed from sleep EEG at different stages. Masking signals were used for solving the mode-mixing problem in HHT. On the other hand, detrended fluctuation analysis (DFA) was used to assess short-term property of HRV denoted as DFA α1, which reflects the temporal activity of autonomic nerve system (ANS). Thus, the dynamic interaction between sleep EEG and HRV can be examined through the relationship between the features of sleep EEG and DFA α1 of HRV.
  
  
  RESULTS
  The frequency feature of sleep EEG serves as a good indicator for the depth of sleep during non-rapid eye movement (NREM) sleep, and amplitude feature of fast-wave oscillation is a good index for distinguishing rapid eye movement (REM) from NREM sleep.
  
  
  CONCLUSIONS
  The relationship between DFA α1 of HRV and the mean amplitude of fast-wave oscillation of sleep EEG affirmed with Pearson correlation coefficient is more significant than the correlation verified by the traditional spectral analysis.
  
  
  CONCLUSIONS
  The dynamic properties of sleep EEG and HRV derived by EMD and DFA represent important features for cortex and ANS activities during sleep.
authors: Research Center for Adaptive Data Analysis and Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taoyuan, Taiwan.
authors: Jia-Rong
authors: JR
authors: Yeh
authors: Chung-Kang
authors: CK
authors: Peng
authors: Men-Tzung
authors: MT
authors: Lo
authors: Chien-Hung
authors: CH
authors: Yeh
authors: Shih-Ching
authors: SC
authors: Chen
authors: Cheng-Yen
authors: CY
authors: Wang
authors: Po-Lei
authors: PL
authors: Lee
authors: Jiunn-Horng
authors: JH
authors: Kang
mesh_terms: D000465:Algorithms; D001341:Autonomic Nervous System / Q000502:physiology; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D017711:Nonlinear Dynamics; D017286:Polysomnography; D012815:Signal Processing, Computer-Assisted; D012894:Sleep Stages / Q000502:physiology*
keywords: Detrended fluctuation analysis; Heart rate variability; Hilbert Huang transform; Sleep EEG; Sympathovagal modulation