Identifying seizure onset zone from electrocorticographic recordings: A machine learning approach based on phase locking value  Bahareh Elahian, Mohammed Yeasin, Basanagoud Mudigoudar, James W. Wheless, Abbas Babajani-Feremi  Seizure - European Journal of Epilepsy  Volume 51, Pages 35-42 (October 2017) DOI: 10.1016/j.seizure.2017.07.010 Copyright © 2017 British Epilepsy Association Terms and Conditions

Fig. 1 Comparison of the average values of PLV across resected and non-resected electrodes in seizure free patients. (a) The EEG recording (before and after seizure onset) in a visually detected SOZ electrode in Patient 1 who was seizure-free after surgery. (b) Average PLV across resected (red) and non-resected (blue) electrodes in Patient 1 are shown. (c) Average PLV was calculated across all resected (red) and non-resected (blue) electrodes in all seizure-free patients. Time zero represents seizure onset. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Seizure - European Journal of Epilepsy 2017 51, 35-42DOI: (10.1016/j.seizure.2017.07.010) Copyright © 2017 British Epilepsy Association Terms and Conditions

Fig. 2 Histogram of the values of PLV in all electrodes in Patient 1. Seizure - European Journal of Epilepsy 2017 51, 35-42DOI: (10.1016/j.seizure.2017.07.010) Copyright © 2017 British Epilepsy Association Terms and Conditions

Fig. 3 Locations of the subdural electrodes, after normalization to the Montreal Neurological Institute (MNI) coordinate system, are shown on top of the cortical surface. Solid dots in red color represent aSOZ electrodes. Yellow circles represent vSOZ electrodes. The broken white lines show the resected areas. In Patient 2, a left anterior interhemispheric strip (LAIH 1–6) and a left posterior interhemispheric strip (LPIH 1–4) are not shown. Two electrodes of LPIH (i.e. LPIH 3 and 4) were resected in Patient 2. An interhemispheric strip with four electrodes are not shown In Patient 7. In Patient 10, an inferior interhemispheric strip (IIH 1–4) and a superior interhemispheric strip (SIH 1–4) are not shown. Two electrodes of IIH (IIH 3 and 4) and two electrodes of SIH (SIH 3 and 4) were resected. Two electrodes of IIH (IIH 3 and 4) and three electrodes of SIH (SIH 2, 3, and 4) were identified as SOZ by our algorithm (aSOZ). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Seizure - European Journal of Epilepsy 2017 51, 35-42DOI: (10.1016/j.seizure.2017.07.010) Copyright © 2017 British Epilepsy Association Terms and Conditions

Fig. 4 Performance of the proposed method. (a) The ROC curve of the proposed classifier in seizure-free patients. (b) Correlation between the number of aSOZ electrodes outside the resected area and the seizure outcome in four non-seizure-free patients. See Section 2.5 for definition of the seizure outcome. Seizure - European Journal of Epilepsy 2017 51, 35-42DOI: (10.1016/j.seizure.2017.07.010) Copyright © 2017 British Epilepsy Association Terms and Conditions