Graph theoretical measures of the fast ripple MI networks improve
the discrimination of non-responders. (A) 3D
scatter plot of the FR (>350 Hz) MI global graph
theoretical measures (three univariate Wilcoxon rank-sum tests,
P > 0.05). (B)
Violin plot of MI computed for SOZ–SOZ edges (red),
SOZ–NSOZ edges (green), NSOZ–NSOZ edges (blue) across all
the responder and non-responder patients (GLMM,
P > 0.05). (C) Local
efficiency of SOZ (red) and NSOZ (blue) nodes across responder and
non-responder patients (GLMM,
P > 0.05). (D) Nodal
strength of SOZ (red) and NSOZ (blue) nodes across responder and
non-responder patients. The location of the node within the SOZ
significantly influenced nodal strength (GLMM,
P < 0.05), (E,
F) 3D scatter plots of the PC scores derived from PCA
of the three global measures (A) from all the patients in
the training set (E) and combined exploratory and test set
(F). The PC2 score was significantly different in the
responders compared with non-responders for the training set (rank-sum,
P = 0.03) and the combined
exploratory and test set patients (rank-sum,
P = 0.01). However, only in the
latter group did the effect survive after Bonferroni–Holm
correction. The PC1 and PC3 scores were not significantly different
rank-sum, P > 0.05).
(G, H, blue) The ROC curve for
non-responder classification in the exploratory dataset (G,
n = 19 responders,
n = 11 non-responders/no
resection or RNS) and in the test dataset (H,
n = 9 responders, 4
non-responders/no resection or RNS) by the SVM-1 trained using the SOZ,
and FR (>350 Hz) distance, rate–distance and three
MI global metric predictors derived from all the exploratory dataset
patients. (G, H, red) The ROC curve for
non-responder classification using SVM-2 in the exploratory
(n = 12 responders,
n = 10 non-responders/no
resection or RNS) and test set patients (H,
n = 9 responders, 4
non-responders/no resection or RNS). SVM-2 excluded RNS implant only
patients in the exploratory dataset prior to training and testing. AUC:
area under the ROC curve.