Invasive Investigation of Insular Cortex Epilepsy
Philippe Ryvlin1, Fabienne Picard
1*Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland; †Institut Des EpilepsiEs (IDEE), Lyon, France; and ‡Department of Clinical Neurosciences, University Hospitals and Medical School of Geneva, Geneva, Switzerland.
Summary
Stereoelectroencephalography (SEEG) is the preferred method for investigating insular epilepsy, offering detailed insights into the insular cortex. SEEG also enables minimally invasive treatments like thermolesion for insular epileptogenic zones.
Area of Science:
- Neurology
- Neurosurgery
- Epileptology
Background:
- Invasive long-term EEG investigations of the insula have been conducted since the mid-1990s for focal epilepsies.
- Various clinical forms of insular epilepsies have been identified, including perisylvian, temporal plus, sleep hypermotor, and MRI-negative epilepsies.
Purpose of the Study:
- To review the role and techniques of stereoelectroencephalography (SEEG) in investigating insular epilepsies.
- To discuss the therapeutic potential of SEEG-guided interventions for insular epilepsy.
Main Methods:
- SEEG is the preferred method for insular investigation, utilizing orthogonal, oblique, or combined trajectories.
- Orthogonal trajectories sample opercula, while oblique trajectories better sample the insular cortex.
- Intrainsular ictal EEG patterns show prolonged focal discharges within specific insular gyri.
Main Results:
- A majority of complex SEEG procedures include electrodes targeting the insula.
- SEEG for insular epilepsy carries no higher risk of intracranial bleeding than in other brain regions.
- Dense sampling of the insular cortex is crucial for suspected insular epilepsies.
Conclusions:
- SEEG is a safe and effective method for investigating insular epilepsies.
- SEEG-guided thermolesion and MRI-guided laser ablation offer potentially safer alternatives to open-skull surgery for insular epilepsy treatment.
