Node abnormality predicts seizure outcome and relates to long-term relapse after epilepsy surgery

Sinha, N.; Wang, Y.; Silva, N.; Miserocchi, A.; McEvoy, A. W.; de Tisi, J.; Vos, S. B.; Winston, G. P.; Duncan, J. S.; Taylor, P. N.

doi:10.1101/747725

bioRxiv · 10.1101/747725

Node abnormality predicts seizure outcome and relates to long-term relapse after epilepsy surgery

Sinha, N.·Wang, Y.·Silva, N.·Miserocchi, A.·McEvoy, A. W.·de Tisi, J.·Vos, S. B.·Winston, G. P.·Duncan, J. S.·Taylor, P. N.

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Abstract

ObjectiveWe assessed pre-operative structural brain networks and clinical characteristics of patients with drug resistant temporal lobe epilepsy (TLE) to identify correlates of post-surgical seizure outcome at 1 year and seizure relapses up to 5 years.\n\nMethodsWe retrospectively examined data from 51 TLE patients who underwent anterior temporal lobe resection (ATLR) and 29 healthy controls. For each patient, using the pre-operative structural, diffusion, and post-operative structural MRI, we generated two networks: pre-surgery network and surgically-spared network. The pre-surgery network is the whole-brain network before surgery and the surgically-spared network is a subnetwork of the pre-surgery network which is expected to remain unaffected by surgery and hence present post-operatively. Standardising these networks with respect to controls, we determined the number of abnormal nodes before surgery and expected to remain after surgery. We incorporated these 2 abnormality measures and 13 commonly acquired clinical data from each patient in a robust machine learning framework to estimate patient-specific chances of seizures persisting after surgery.\n\nResultsPatients with more abnormal nodes had lower chance of seizure freedom at 1 year and even if seizure free at 1 year, were more likely to relapse within five years. In the surgically-spared networks of poor outcome patients, the number of abnormal nodes was greater and their locations more widespread than in good outcome patients. We achieved 0.84 {+/-} 0.06 AUC and 0.89 {+/-} 0.09 specificity in detecting unsuccessful seizure outcomes at 1-year. Moreover, the model-predicted likelihood of seizure relapse was significantly correlated with the grade of surgical outcome at year-one and associated with relapses up-to five years post-surgery.\n\nConclusionNode abnormality offers a personalised non-invasive marker, that can be combined with clinical data, to better estimate the chances of seizure freedom at 1 year, and subsequent relapse up to 5 years after ATLR.

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Sinha, N., Wang, Y., Silva, N., Miserocchi, A., McEvoy, A. W., de Tisi, J., Vos, S. B., Winston, G. P., Duncan, J. S., Taylor, P. N.. 2019-09-01. Node abnormality predicts seizure outcome and relates to long-term relapse after epilepsy surgery. https://doi.org/10.1101/747725

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