Diagnostic and therapeutic approaches in refractory insular epilepsy

Due to heterogenous seizure semiology and poor contribution of scalp electroencephalography (EEG) signals, insular epilepsy requires use of the appropriate diagnostic tools for its diagnosis and characterization. The deep location of the insula also presents surgical challenges. The aim of this article is to review the current diagnostic and therapeutic tools and their contribution to the management of insular epilepsy. Magnetic resonance imaging (MRI), isotopic imaging, neurophysiological imaging, and genetic testing should be used and interpretated with caution. Isotopic imaging and scalp EEG have demonstrated a lower value in epilepsy from insular compared to temporal origin, which increases the interest of functional MRI and magnetoencephalography. Intracranial recording with stereo-electroencephalography (SEEG) is often required. The insular cortex, being highly connected and deeply located under highly functional areas, is difficult to reach, and its ablative surgery raises functional issues. Tailored resection based on SEEG or alternative curative treatments, such as radiofrequency thermocoagulation, laser interstitial thermal therapy, or stereotactic radiosurgery, have produced encouraging results. The management of insular epilepsy has benefited from major advances in the last years. Perspectives for diagnostic and therapeutic procedures will contribute to better management of this complex form of epilepsy.