{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T06:42:52Z","timestamp":1768718572505,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2013,8,23]],"date-time":"2013-08-23T00:00:00Z","timestamp":1377216000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>EEG (Electroencephalography) signals can express the human awareness activities and consequently it can indicate the depth of anesthesia. On the other hand, Bispectral-index (BIS) is often used as an indicator to assess the depth of anesthesia. This study is aimed at using an advanced signal processing method to analyze EEG signals and compare them with existing BIS indexes from a commercial product (i.e., IntelliVue MP60 BIS module). Multivariate empirical mode decomposition (MEMD) algorithm is utilized to filter the EEG signals. A combination of two MEMD components (IMF2 + IMF3) is used to express the raw EEG. Then, sample entropy algorithm is used to calculate the complexity of the patients\u2019 EEG signal. Furthermore, linear regression and artificial neural network (ANN) methods were used to model the sample entropy using BIS index as the gold standard. ANN can produce better target value than linear regression. The correlation coefficient is 0.790 \u00b1 0.069 and MAE is 8.448 \u00b1 1.887. In conclusion, the area under the receiver operating characteristic (ROC) curve (AUC) of sample entropy value using ANN and MEMD is  0.969 \u00b1 0.028 while the AUC of sample entropy value without filter is 0.733 \u00b1 0.123. It means the MEMD method can filter out noise of the brain waves, so that the sample entropy of EEG can be closely related to the depth of anesthesia. Therefore, the resulting index can be adopted as the reference for the physician, in order to reduce the risk of surgery.<\/jats:p>","DOI":"10.3390\/e15093325","type":"journal-article","created":{"date-parts":[[2013,8,23]],"date-time":"2013-08-23T11:38:05Z","timestamp":1377257885000},"page":"3325-3339","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":62,"title":["Application of Multivariate Empirical Mode Decomposition and Sample Entropy in EEG Signals via Artificial Neural Networks for Interpreting Depth of Anesthesia"],"prefix":"10.3390","volume":"15","author":[{"given":"Jeng-Rung","family":"Huang","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Yuan Ze University, Taoyuan, Chung-Li, 32003, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6849-8453","authenticated-orcid":false,"given":"Shou-Zen","family":"Fan","sequence":"additional","affiliation":[{"name":"Department of Anesthesiology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8515-7933","authenticated-orcid":false,"given":"Maysam","family":"Abbod","sequence":"additional","affiliation":[{"name":"School of Engineering and Design, Brunel University, London, UB8 3PH, UK"}]},{"given":"Kuo-Kuang","family":"Jen","sequence":"additional","affiliation":[{"name":"Missile & Rocket Systems Research Division, Chung-Shan Institute of Science and Technology, Taoyuan, Longtan, 32500, Taiwan"}]},{"given":"Jeng-Fu","family":"Wu","sequence":"additional","affiliation":[{"name":"Missile & Rocket Systems Research Division, Chung-Shan Institute of Science and Technology, Taoyuan, Longtan, 32500, Taiwan"}]},{"given":"Jiann-Shing","family":"Shieh","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Yuan Ze University, Taoyuan, Chung-Li, 32003, Taiwan"},{"name":"Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chung-Li, 32001, Taiwan"}]}],"member":"1968","published-online":{"date-parts":[[2013,8,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"782","DOI":"10.1097\/ACO.0b013e3283326986","article-title":"Depth of anesthesia","volume":"22","author":"Kent","year":"2009","journal-title":"Curr. 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