Bulletin of the Russian Military Medical AcademyBulletin of the Russian Military Medical Academy1682-73922687-1424Eco-Vector1225010.17816/brmma12250Research ArticleAnalysis of decreased bioelectric activity of a brain with pharmacoresistant epilepsyArkhipovaN Bexeast@gmail.comUlitinA Yu-AlexandrovM V-15092018202768001052019Copyright © 2018, Arkhipova N.B., Ulitin A.Y., Alexandrov M.V.2018High-frequency bioelectrical activity in pharmacoresistant epilepsy is analyzed. It has been established that pathologic high-frequency oscillations are a potential marker of the epileptogenic zone. We propose a classification of pathological high-frequency oscillations: 1) continuous high-frequency oscillations; 2) modulated pathological high-frequency oscillations, associated with slow waves; 3) modulated pathological high-frequency oscillations, associated with spikes. An example illustrating the application of the analysis of high-frequency bioelectrical activity for the localization of the epileptogenic zone in the widespread irritative zone is given. Variants of interrelation of the regions generating pathological high-frequency activity and epileptic activity in the range up to 70 Hz are demonstrated. Recording of epileptic activity in the frequency range up to 70 Hz is not an exclusive criterion of the epileptogenesis. Recording of modulated pathological high- frequency oscillations associated with spikes allows the differentiation of two spike types. We can assume that the mechanism for generating spikes containing high-frequency component differs from the one for plain spikes. The generators of the pathological high-frequency oscillations are characterized by a smaller size, which should allow more precise localization of the focus of pathological activity. In some cases, the analysis of the high-frequency component of the electrocorticogram makes it possible to differentiate the secondary irritative zone. It has been demonstrated that in patients with extratemporal, especially frontal, epileptogenic zone localization pathological high-frequency oscillations provide additional information about the location of the generator of abnormal activity.medically intractable epilepsyepilepsy surgerypreoperative assessmentepileptogenic zoneepileptic activityirritative zoneelectrocorticographyinvasive monitoringpathological high-frequency oscillationsфармакорезистентная эпилепсияхирургическое лечение эпилепсиипредоперационное обследованиеэпилептогенная зонаэпилептическая активностьзона ирритацииэлектрокортикографияинвазивный мониторингпатологические высокочастотные осцилляции[Александров, М.В. Анализ биоэлектрической активности го- ловного мозга высокочастотного диапазона при эпилепсии / М.В. Александров, Н.Б. Архипова // Клиническая нейро- физиология и нейрореабилитация: мат. пятой научн.-практ. конф. с междунар. участием. - СПб., 2017. - С. 9-10.][Александров, М.В. Интраоперационная электрокортико- графия: возможности и перспективы / М.В. Александров, А.Ю. Улитин // Вестн. Росс. воен.-мед. акад. - 2012. - № 4 (40). - С. 245-254.][Александров, М.В. Структурно-функциональная организация эпилептического очага / М.В. Александров [и др.] // Росс. нейрохирург. жур. им. проф. А.Л. Поленова. - 2017. - Т.9. - № 2. - С. 5-9.][Костенко, И.А. Эффективность интраоперационной электро- кортикографии при симптоматической эпилепсии, ассоци- ированной с опухолями головного мозга / И.А. Костенко [и др.] // Вестн. Росс. воен.-мед. акад. - 2017. - Т. 59. - № 3. - С. 42-46.][Arkhipova, N. P339 Long-term electrocorticographic monitoring and pathological high-frequency oscillations in tumor-related epilepsy / N. Arkhipova [et al.] // Clinical Neurophysiology. - 2017. - Vol. 128. - № 9 (128). - P. e288.][Frauscher, B. High-frequency oscillations: The state of clinical research / B. Frauscher [et al.] // Epilepsia. - 2017. - Vol. 58. - № 8. - P. 1316-1329.][Luders, H.O. General principles of presurgical evaluation / HO L-ders, M Carre-o // Textbook of epilepsy surgery / H.O. Luders, (ed.) - CRC Press - 2008. - P. 409-422.][Roehri, N. High-frequency oscillations are not better biomarkers of epileptogenic tissues than spikes / N. Roehri [et al.] // Annals of neurology. - 2018. - Vol. 83. - № 1. - P. 84-97.][Zijlmans, M. How to record high-frequency oscillations in epilepsy: A practical guideline / M. Zijlmans [et al.] // Epilepsia. - 2017. - Vol. 58. - № 8 - P. 1305-1315.]