EpiGrid: Soft and flexible high density electrode grids for epilepsy surgery

Introduction

Epilepsy is a highly prevalent brain disorder affecting 1% of the population. Brain surgery can cure epilepsy if we can delineate the diseased tissue intra-operatively. Unfortunately, this delineation is currently not performed precisely and leads to poor success rates (50-70%).

High Frequency Oscillations (HFOs)

High frequency oscillations (HFOs) have been identified as a biomarker of epileptogenic tissues, which can be electrically recorded with intraoperative electrocorticography.

Specificity of HFOs

These HFOs are specific to diseased epileptogenic brain tissues and their remnant after an initial resection predicts continuation of seizures after surgery, thus indicating incomplete removal.

Limitations of Current Electrode Grids

The problem is that currently available electrode grids do not provide adequate recording resolution due to:

1. Low electrode density.
2. Stiff materials that yield a low signal-to-noise level when recording from the cortical surface.
3. Inability to record from within resection cavities, as the rigid electrodes cannot conform to the curvature of the cavity.

Need for Improved Electrode Grids

We need high density flexible electrode grids that can adhere to the cortical surface and cavities. Neurosoft Bioelectronics produces flexible and high density electrode grids based on unique stretchable soft electrodes.

Project Goals

Our goal is to use this grant to translate our clinical needs into an optimal design of soft electrode grids adapted for epilepsy surgery, with the help of an industrial designer.

Testing and Implementation

We will first test these newly designed soft electrodes in vitro for clinical handability and improved signal quality, and eventually test them during epilepsy surgery in 12 patients.

Comparison of Outcomes

The recorded signals and clinical outcomes will be compared to those from standard rigid electrode grids.

Expected Impact

Improved delineation of the epileptogenic tissue will lead to a higher success rate, make epilepsy surgery a first choice treatment, and overall change this otherwise life-long disease into a curable disorder for many people.