Diagnostic and therapeutic approaches in refractory insular epilepsy

Abstract

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 stereoelectroencephalography (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.

From cryogenic to on‐scalp magnetoencephalography for the evaluation of paediatric epilepsy

“…25 The higher yield of MEG in ETLE compared with TLE can be easily understood. First, as neuromagnetic fields are not influenced by the layers they pass through and MEG has a heightened sensitivity to tangential sources, MEG is superior to EEG in detecting IEDs originating from the perisylvian/insular cortices, 5,28 and from bottom-of-sulcus focal cortical dysplasia. 5 The localization value of temporal IEDs requires more interpretation to distinguish mesiotemporal from neocortical sources and to establish their pathological nature.…”

Tri-axial rubidium and helium optically pumped magnetometers for on-scalp magnetoencephalography recording of interictal epileptiform discharges: a case study

“…In the case of pediatric epilepsy, the reduced brain-sensor distance afforded by on-scalp Rb-OPM-MEG led to higher IED amplitude and SNR compared with cryogenic MEG ( Feys et al, 2022 ). The advent of Rb-OPM has thus ignited a revolution in the field of MEG and human neurosciences ( Boto et al, 2018 ), and might—in time—become a reference method for the diagnostic evaluation of focal epilepsy ( Brookes et al, 2022 ; Feys et al, 2022 ; Pedersen et al, 2022 ; Feys et al, 2023c ; Feys and De Tiège, 2023 ).…”

Interest of tri-axial rubidium and helium optically pumped magnetometers for on-scalp magnetoencephalography recording of interictal epileptiform discharges

“…In the case of pediatric epilepsy, the reduced brain-sensor distance afforded by on-scalp Rb-OPM-MEG led to higher IED amplitude and SNR compared with cryogenic MEG (14). The advent of Rb-OPM has thus ignited a revolution in the field of MEG and human neurosciences (7), and might-in time-become a reference method for the diagnostic evaluation of focal epilepsy (14,(19)(20)(21)(22).…”