TY - JOUR
T1 - Effects of a stable concentration of propofol on interictal high-frequency oscillations in drug-resistant epilepsy
AU - Inada, Taku
AU - Kobayashi, Katsuya
AU - Kikuchi, Takayuki
AU - Matsuhashi, Masao
AU - Matsumoto, Riki
AU - Takahashi, Yuki
AU - Nakae, Takuro
AU - Shibata, Sumiya
AU - Yamao, Yukihiro
AU - Daifu, Masako
AU - Togawa, Jumpei
AU - Yoshida, Kazumichi
AU - Kunieda, Takeharu
AU - Kobayashi, Katsuhiro
AU - Ikeda, Akio
AU - Miyamoto, Susumu
N1 - Funding Information:
This work was partly supported by the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) KAKENHI Grant Numbers 15H05874, 15K10361, 17K16120, 17K10892, and 19K18424, the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant number 26293209), and research grants from the Japan Epilepsy Foundation and the Japan Brain Foundation.
Funding Information:
The Industry‐Academia Collaboration Courses of The Department of Epilepsy, Movement Disorders and Physiology is supported by Eisai Co., Ltd., Nihon Kohden Corporation, Otsuka Pharmaceutical Co., and UCB Japan Co., Ltd. These companies did not play any role in this study, the preparation of the manuscript, or the decision to publish the result.
Publisher Copyright:
© 2021 Epileptic Disorders
PY - 2021/4
Y1 - 2021/4
N2 - Objective. The aim of this study was to clarify the effect of a stable concentration of propofol on interictal high-frequency oscillations (HFOs), which may contribute to identifying the epileptogenic zone intraoperatively for resection surgery. Methods. Nine patients with drug-resistant focal epilepsy who underwent invasive pre-surgical evaluation with chronic subdural electrodes were recruited. Five-minute electrocorticograms during wakefulness, slow-wave sleep, and under a stable brain concentration of propofol were recorded with the same electrodes. In each patient, 1–10 pairs of electrodes were selected for both electrodes with EEG changes within 5 seconds from the ictal onset (ictal pattern for 5 seconds [IP5]) and those outside the area of IP5 with no interictal epileptiform discharges (non-epileptiform [nEPI]). The numbers of ripples (80-250 Hz) and fast ripples (>250 Hz) were measured semi-automatically using an established algorithm. Statistical testing was performed with a mixed effect model. Results. Thirty-seven pairs of electrodes from nine patients were analysed for IP5 and 29 pairs from seven patients were analysed for nEPI. The numbers of HFOs differed between the areas (IP5 and nEPI) and among the conditions (wakefulness, slow-wave sleep, propofol anaesthesia) (all p <0.01). The HFO occurrence rates were significantly higher for IP5 than those for nEPI in all conditions (for both ripples and fast ripples in all conditions; p <0.01). Significance. The occurrence rates of HFOs for IP5 were significantly higher than those for nEPI under propofol anaesthesia. These are fundamental findings for intraoperative HFO analysis, however, the following limitations should be considered: physiological HFOs could not be completely differentiated from pathological HFOs; in order to apply an HFO detector, an appropriate cut-off threshold is needed; an artefact of the impulse response filter appears as an HFO; and the series was comprised of a small number of heterogeneous patients.
AB - Objective. The aim of this study was to clarify the effect of a stable concentration of propofol on interictal high-frequency oscillations (HFOs), which may contribute to identifying the epileptogenic zone intraoperatively for resection surgery. Methods. Nine patients with drug-resistant focal epilepsy who underwent invasive pre-surgical evaluation with chronic subdural electrodes were recruited. Five-minute electrocorticograms during wakefulness, slow-wave sleep, and under a stable brain concentration of propofol were recorded with the same electrodes. In each patient, 1–10 pairs of electrodes were selected for both electrodes with EEG changes within 5 seconds from the ictal onset (ictal pattern for 5 seconds [IP5]) and those outside the area of IP5 with no interictal epileptiform discharges (non-epileptiform [nEPI]). The numbers of ripples (80-250 Hz) and fast ripples (>250 Hz) were measured semi-automatically using an established algorithm. Statistical testing was performed with a mixed effect model. Results. Thirty-seven pairs of electrodes from nine patients were analysed for IP5 and 29 pairs from seven patients were analysed for nEPI. The numbers of HFOs differed between the areas (IP5 and nEPI) and among the conditions (wakefulness, slow-wave sleep, propofol anaesthesia) (all p <0.01). The HFO occurrence rates were significantly higher for IP5 than those for nEPI in all conditions (for both ripples and fast ripples in all conditions; p <0.01). Significance. The occurrence rates of HFOs for IP5 were significantly higher than those for nEPI under propofol anaesthesia. These are fundamental findings for intraoperative HFO analysis, however, the following limitations should be considered: physiological HFOs could not be completely differentiated from pathological HFOs; in order to apply an HFO detector, an appropriate cut-off threshold is needed; an artefact of the impulse response filter appears as an HFO; and the series was comprised of a small number of heterogeneous patients.
KW - electrocorticogram
KW - epileptogenic zone
KW - high-frequency oscillations
KW - intraoperative recording
KW - propofol anaesthesia
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U2 - 10.1684/epd.2021.1264
DO - 10.1684/epd.2021.1264
M3 - Article
C2 - 33855965
AN - SCOPUS:85106553859
SN - 1294-9361
VL - 23
SP - 299
EP - 312
JO - Epileptic Disorders
JF - Epileptic Disorders
IS - 2
ER -