OC-15 | Electroencephalography recording during visual aura in migraine: results by quantitative analysis

Salvatore Maria Lima,¹ Massimo Gangitano,¹ Vincenzo Di Stefano,¹ Vincenzo Raieli,² Filippo Brighina¹ | ¹Department of Biomedicine, Neuroscience, and advanced Diagnostic (BIND), University of Palermo; ²Child Neurology and Psychiatry Unit-ISMEP, "G. Di Cristina" Children's Hospital-ARNAS Civico, Palermo, Italy

Background: Migraine with aura represents 20-30% of all forms of migraine (1) and usually precedes the migraine attack, lasts from 5 to 60 minutes and is characterized by transient neurological deficits (2) (3). Quantitative Electroencephalography (qEEG), a powerful tool used to study cerebral cortical activity, was employed to investigate the variation of cortical activity during a complete visual aura.

Methods: We recorded an EEG in a patient affected by migraine for the entire duration of a visual aura; then, using “EEGLAB” software the EEG trace was divided into 13 epochs and the quantitative analysis was performed on each epoch, evaluating the evolution of cortical activity over time in relation to 19 frequencies (from 2 to 20 Hz) and, vice versa, evaluating the cortical activity as a function of the 19 frequencies for each epoch.

Results: During the initial phase of aura, all cortical regions exhibited an increase in power activity, which was subsequently followed by a reduction, especially in one hemisphere, outlining an "asymmetry index" between the two hemispheres that gradually increases throughout the duration of the aura.

Conclusion: These results, in addition to clarifying the timing of electroencephalographic depression in a specific moment of the aura related to Cortical Spreading Depression (CSD), may have important clinical implications in the neurointensive monitoring of cerebral acuities that use the CSD as a neurophysiological biomarker. In addition, evaluating power activity as a function of the 19 frequencies, revealed a generalized decrease in power activity throughout all cortical areas, extending beyond the posterior regions. This neurophysiopathological observation, documented here for the first time, supports the few existing neurobiological findings in this field.

References

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2. Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018;38(1):1-211. doi:10.1177/0333102417738202. 
3. Barbanti P, Brighina F, Egeo G, Di Stefano V, Silvestro M, Russo A. Migraine as a Cortical Brain Disorder. Headache. 2020;60(9):2103-2114. doi:10.1111/head.13935.