TY - JOUR
T1 - Temporal correlation between two channels EEG of bipolar lead in the head midline is associated with sleep-wake stages
AU - Li, Yanjun
AU - Tang, Xiaoying
AU - Xu, Zhi
AU - Liu, Weifeng
AU - Li, Jing
N1 - Publisher Copyright:
© 2016, Australasian College of Physical Scientists and Engineers in Medicine.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - Whether the temporal correlation between inter-leads Electroencephalogram (EEG) that located on the boundary between left and right brain hemispheres is associated with sleep stages or not is still unknown. The purpose of this paper is to evaluate the role of correlation coefficients between EEG leads Fpz-Cz and Pz-Oz for automatic classification of sleep stages. A total number of 39 EEG recordings (about 20 h each) were selected from the expanded sleep database in European data format for temporal correlation analysis. Original waveform of EEG was decomposed into sub-bands δ (1–4 Hz), θ (4–8 Hz), α (8–13 Hz) and β (13–30 Hz). The correlation coefficient between original EEG leads Fpz-Cz and Pz-Oz within frequency band 0.5–30 Hz was defined as rEEG and was calculated every 30 s, while that between the two leads EEG in sub-bands δ, θ, α and β were defined as rδ, rθ, rα and rβ, respectively. Classification of wakefulness and sleep was processed by fixed threshold that derived from the probability density function of correlation coefficients. There was no correlation between EEG leads Fpz-Cz and Pz-Oz during wakefulness (|r| < 0.1 for rθ, rα and rβ, while 0.3 > r > 0.1 for rEEG and rδ), while low correlation existed during sleep (r ≈ −0.4 for rEEG, rδ, rθ, rα and rβ). There were significant differences (analysis of variance, P < 0.001) for rEEG, rδ, rθ, rα and rβ during sleep when in comparison with that during wakefulness, respectively. The accuracy for distinguishing states between wakefulness and sleep was 94.2, 93.4, 89.4, 85.2 and 91.4 % in terms of rEEG, rδ, rθ, rα and rβ, respectively. However, no correlation index between EEG leads Fpz-Cz and Pz-Oz could distinguish all five types of wakefulness, rapid eye movement (REM) sleep, N1 sleep, N2 sleep and N3 sleep. In conclusion, the temporal correlation between EEG bipolar leads Fpz-Cz and Pz-Oz are highly associated with sleep-wake stages. Moreover, high accuracy of sleep-wake classification could be achieved by the temporal correlation within frequency band 0.5–30 Hz between EEG leads Fpz-Cz and Pz-Oz.
AB - Whether the temporal correlation between inter-leads Electroencephalogram (EEG) that located on the boundary between left and right brain hemispheres is associated with sleep stages or not is still unknown. The purpose of this paper is to evaluate the role of correlation coefficients between EEG leads Fpz-Cz and Pz-Oz for automatic classification of sleep stages. A total number of 39 EEG recordings (about 20 h each) were selected from the expanded sleep database in European data format for temporal correlation analysis. Original waveform of EEG was decomposed into sub-bands δ (1–4 Hz), θ (4–8 Hz), α (8–13 Hz) and β (13–30 Hz). The correlation coefficient between original EEG leads Fpz-Cz and Pz-Oz within frequency band 0.5–30 Hz was defined as rEEG and was calculated every 30 s, while that between the two leads EEG in sub-bands δ, θ, α and β were defined as rδ, rθ, rα and rβ, respectively. Classification of wakefulness and sleep was processed by fixed threshold that derived from the probability density function of correlation coefficients. There was no correlation between EEG leads Fpz-Cz and Pz-Oz during wakefulness (|r| < 0.1 for rθ, rα and rβ, while 0.3 > r > 0.1 for rEEG and rδ), while low correlation existed during sleep (r ≈ −0.4 for rEEG, rδ, rθ, rα and rβ). There were significant differences (analysis of variance, P < 0.001) for rEEG, rδ, rθ, rα and rβ during sleep when in comparison with that during wakefulness, respectively. The accuracy for distinguishing states between wakefulness and sleep was 94.2, 93.4, 89.4, 85.2 and 91.4 % in terms of rEEG, rδ, rθ, rα and rβ, respectively. However, no correlation index between EEG leads Fpz-Cz and Pz-Oz could distinguish all five types of wakefulness, rapid eye movement (REM) sleep, N1 sleep, N2 sleep and N3 sleep. In conclusion, the temporal correlation between EEG bipolar leads Fpz-Cz and Pz-Oz are highly associated with sleep-wake stages. Moreover, high accuracy of sleep-wake classification could be achieved by the temporal correlation within frequency band 0.5–30 Hz between EEG leads Fpz-Cz and Pz-Oz.
KW - Correlation coefficient
KW - EEG
KW - Sleep scoring
KW - Sleep stage classification
KW - Sleep-wake classification
KW - Synchronization
KW - Temporal correlation
UR - http://www.scopus.com/inward/record.url?scp=84959490175&partnerID=8YFLogxK
U2 - 10.1007/s13246-015-0409-7
DO - 10.1007/s13246-015-0409-7
M3 - Article
C2 - 26934877
AN - SCOPUS:84959490175
SN - 0158-9938
VL - 39
SP - 147
EP - 155
JO - Australasian Physical and Engineering Sciences in Medicine
JF - Australasian Physical and Engineering Sciences in Medicine
IS - 1
ER -