Neural Fragility of the Intracranial EEG Network Decreases after Surgical Resection of the Epileptogenic Zone

Over 15 million patients with epilepsy worldwide do not respond to medical therapy and may benefit from surgical treatment. In focal epilepsy, surgical treatment requires complete removal or disconnection of the epileptogenic zone (EZ). However, despite detailed multimodal pre-operative assessment, surgical success rates vary and may be as low as 30% in the most challenging cases. Here we demonstrate that neural fragility, a dynamical networked-system biomarker of epileptogenicity, decreases following successful surgical resection. Moreover, neural fragility increases or remains constant when seizure-freedom is not achieved. We demonstrate this retrospectively in a virtual patient with epilepsy using the Virtual Brain neuroinformatics platform, and subsequently on six children with epilepsy with pre- and post-resection intra-operative recordings. Finally, we compare neural fragility as a putative biomarker of epileptogenicity against established spectral metrics, such as high frequency oscillations and find that neural fragility is a superior biomarker of epileptogenicity.