Resting-state EEG power and coherence vary between migraine phases.
BACKGROUND
Migraine is characterized by a series of phases (inter-ictal, pre-ictal, ictal, and post-ictal). It is of great interest whether resting-state electroencephalography (EEG) is differentiable between these phases.


METHODS
We compared resting-state EEG energy intensity and effective connectivity in different migraine phases using EEG power and coherence analyses in patients with migraine without aura as compared with healthy controls (HCs). EEG power and isolated effective coherence of delta (1-3.5 Hz), theta (4-7.5 Hz), alpha (8-12.5 Hz), and beta (13-30 Hz) bands were calculated in the frontal, central, temporal, parietal, and occipital regions.


RESULTS
Fifty patients with episodic migraine (1-5 headache days/month) and 20 HCs completed the study. Patients were classified into inter-ictal, pre-ictal, ictal, and post-ictal phases (n = 22, 12, 8, 8, respectively), using 36-h criteria. Compared to HCs, inter-ictal and ictal patients, but not pre- or post-ictal patients, had lower EEG power and coherence, except for a higher effective connectivity in fronto-occipital network in inter-ictal patients (p < .05). Compared to data obtained from the inter-ictal group, EEG power and coherence were increased in the pre-ictal group, with the exception of a lower effective connectivity in fronto-occipital network (p < .05). Inter-ictal and ictal patients had decreased EEG power and coherence relative to HCs, which were "normalized" in the pre-ictal or post-ictal groups.


CONCLUSIONS
Resting-state EEG power density and effective connectivity differ between migraine phases and provide an insight into the complex neurophysiology of migraine.
Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, Australia.|Department of Electrical and Computer Engineering, Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan.|Brain Research Center, National Chiao Tung University, Hsinchu, Taiwan.
Zehong
Z
Cao
Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, Australia. Chin-Teng.Lin@uts.edu.au.|Brain Research Center, National Chiao Tung University, Hsinchu, Taiwan. Chin-Teng.Lin@uts.edu.au.
Chin-Teng
CT
Lin
Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, Australia.|Brain Research Center, National Chiao Tung University, Hsinchu, Taiwan.
Chun-Hsiang
CH
Chuang
Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.|Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
Kuan-Lin
KL
Lai
Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan.|Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.|Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA.
Albert C
AC
Yang
Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.|Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
Jong-Ling
JL
Fuh
Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan. sjwang@vghtpe.gov.tw.|Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan. sjwang@vghtpe.gov.tw.|Brain Research Center, National Yang-Ming University, Taipei, Taiwan. sjwang@vghtpe.gov.tw.
Shuu-Jiun
SJ
Wang
D000328:Adult; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020326:Migraine without Aura / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology; D055815:Young Adult
EEG; Isolated effective coherence; Migraine without aura; Power; Resting-state