Analysis of EEG signals under flash stimulation for migraine and epileptic patients.

Migraine and epilepsy are both persistent disorders characterised by recurrent neurological attacks. Visual symptoms and hypersensitivity to light stimuli are frequent in migraine. Analysis of EEG signals under flash stimulation for migraine and epileptic patients is not a new method. But magnitude increasing under flash stimulation for migraine patients has not been studied yet. The aims of this study is the analysis of multichannel electroencephalogram (EEG) in migraine and epileptic patients by visual evoked potentials (VEP) and investigate the existence of magnitude increasing under flash stimulation for migraine patients. In this study as a method of flash stimuli at frequencies of 2, 4 and 6 Hz were applied to different migraine and epileptic patients under pain-free phase with the EEG recorded from 18 scalp electrodes, referred to the linked earlobes. We used AR parametric method to analyze and characterize EEG signals in migraine and epileptic patients. The variations in the EEG power spectra shapes were examined in order to obtain medical information. These power spectra were then used to compare the applied method in terms of their frequency resolution and the effects in determination of migraine and epilepsy. Global performance of the proposed methods was evaluated by means of the visual inspection of power spectral densities (PSDs). For the migraine patients, an increase in amplitude has observed at the beta bands of EEG signals under flash stimulation as compared to EEG signals without stimulation. As opposed to this, for epileptic patients, an increase in amplitude has observed at the alpha bands of EEG signals without flash stimulation. Meanwhile for the control groups, there is no change between EEG signals under flash stimulation and without flash stimulation.