Non-linear electroencephalogram dynamics in patients with spontaneous nocturnal migraine attacks

The present study was conducted to examine non-linear electroencephalogram (EEG) measures during the development of a spontaneous migraine attack. We investigated the sleep EEG of five patients with migraine without aura in t he pain-free interval and at the onset of a nocturnal attack. Sleep EEG rec ordings were analysed using the method of global dimensional complexity com pared to conventional sleep scoring techniques. We found no divergence betw een classical sleep architecture and the estimated dimensional course nor a ny relevant short-term changes related to the onset of headache. There was, however, a loss of dimensional complexity in the first two non-rapid eye m ovement sleep states in the migraine night, with statistical significance d uring the second sleep cycle. For the first time, these results provide evi dence of a global dimension decrease that is related to cortical network ch anges during a migraine attack. (C) 2001 Published by Elsevier Science Irel and Ltd.