Periodic Reporting for period 4 - Epilepsy_Core (The core and effects of epilepsy: from chronic disease to curable disorder through innovative guided surgery)
Reporting period: 2023-09-01 to 2025-08-31
Epilepsy is a common neurological disease which affects people's tremendously. It affects peoples lives in many ways, not only by causing seizures, but also by disturbing the normal brain to function at 100%. If the origin of epileptic activity in the brain is focal, it can be cured by epilepsy surgery. This is currently successful in 50-70%, but this number can increase if we would be able to define the focus of epilepsy more precisely. The goal of our project was to delineate the focus of epilepsy with intra-operative recordings of the electrical brain activity, and look for small vibrations in the signal: high frequency oscillations (HFOs). The project objectives were to improve both the recording methods and the signal analysis methods to better define the core of epilepsy and to understand the effect of epileptic activity on the rest of the healthy brain.
We built a database of previous invasive EEG and innovated the recordings themselves. We used advanced signal analysis methods including machine learning to better recognize the epileptic activity and found several complementary signal biomarkers. We used high-density electrode grids and found that this improved detecting the small HFOs and potentiated more precise recognition of epileptic tissue by advanced signal analysis. We developed flexible electrode that can record from within a resection cavity to check if all diseased tissue has been removed. We used short stimulations to find the diseased tissue which responds differently to stimulation than healthy tissue. We found ways to recognize the position of the electrode grids during surgery, which is needed for to directly guide the neurosurgeon by projecting the signal analysis results.
The project gained us insight into the pathophysiology of epilepsy. We found that removing tissue producing epileptic activity has a positive effect on cognition. We studied people with brain tumors and epilepsy and found that the invasive EEG recordings recognizes infiltrative tumor growth and inflammation. This shows that understanding and optimal recording of the epileptic brain signal can improve not only the direct effects of epilepsy surgery to stop seizures, but also aids optimal effects on cognition and tumor removal.
The next step that is needed is to build a system that combines optimal recording, analysis and feedforward projection of results on the brain surface to guide neurosurgeons.
We built a database of previous invasive EEG and innovated the recordings themselves. We used advanced signal analysis methods including machine learning to better recognize the epileptic activity and found several complementary signal biomarkers. We used high-density electrode grids and found that this improved detecting the small HFOs and potentiated more precise recognition of epileptic tissue by advanced signal analysis. We developed flexible electrode that can record from within a resection cavity to check if all diseased tissue has been removed. We used short stimulations to find the diseased tissue which responds differently to stimulation than healthy tissue. We found ways to recognize the position of the electrode grids during surgery, which is needed for to directly guide the neurosurgeon by projecting the signal analysis results.
The project gained us insight into the pathophysiology of epilepsy. We found that removing tissue producing epileptic activity has a positive effect on cognition. We studied people with brain tumors and epilepsy and found that the invasive EEG recordings recognizes infiltrative tumor growth and inflammation. This shows that understanding and optimal recording of the epileptic brain signal can improve not only the direct effects of epilepsy surgery to stop seizures, but also aids optimal effects on cognition and tumor removal.
The next step that is needed is to build a system that combines optimal recording, analysis and feedforward projection of results on the brain surface to guide neurosurgeons.
We build a database of over 1000 people who underwent epilepsy surgery and over 400 invasive EEG recordings and we are putting all data into a uniform structure. This database will allow future signal analysis using advanced signal analysis methods and artificial intelligence.
We compared epileptic activity to inflammation markers in the brain, and found that the spread of epileptic activity was associated with increased inflammation. We compared cognitive functioning in terms of IQ to epileptic activity but did not find a direct relation there. We also looked at how different lesions and sites in the brain affect epileptic activity. This work is still in progress. We started performing the first high-density electrocorticography recording during surgery, this was delayed due to the COVID pandemic. We started developing software for better visualisation of intra-operative recordings and we started up a collaboration with a company that produces special electrode grids to develop electrodes that fulfill our needs better.
We compared epileptic activity to inflammation markers in the brain, and found that the spread of epileptic activity was associated with increased inflammation. We compared cognitive functioning in terms of IQ to epileptic activity but did not find a direct relation there. We also looked at how different lesions and sites in the brain affect epileptic activity. This work is still in progress. We started performing the first high-density electrocorticography recording during surgery, this was delayed due to the COVID pandemic. We started developing software for better visualisation of intra-operative recordings and we started up a collaboration with a company that produces special electrode grids to develop electrodes that fulfill our needs better.
The size of our database is unique and this will allow future extensive signal analysis research and progress.
We started up a very complementary collaboration with a medical start-up company to develop special electrode grids for our purposes. This can shift possibilities as these recordings are yet not possible.
We expect that at the end of the project we have advanced recording and analysis techniques and hopefully already have software that can bring this all together to translate this progress into clinical valuable tools.
We started up a very complementary collaboration with a medical start-up company to develop special electrode grids for our purposes. This can shift possibilities as these recordings are yet not possible.
We expect that at the end of the project we have advanced recording and analysis techniques and hopefully already have software that can bring this all together to translate this progress into clinical valuable tools.