Faculty
Schulich School of Medicine & Dentistry
Supervisor Name
Dr. Ana Suller Marti
Keywords
epilepsy, depth electrode, iEEG, implantation effect
Description
Rationale: The implantation effect describes an immediate reduction in seizure frequency following the insertion of intracranial electrodes. There is limited information regarding which patients will experience a reduction of seizures and the reason for the implantation effect. This study focuses on describing predictor factors for the reduction in seizure frequency in patients with medically resistant epilepsy implanted with depth electrodes.
Methods: We conducted a retrospective chart review of 89 patients who underwent intracranial electroencephalography (iEEG) monitoring with depth electrodes. Sixty-five of these patients had no subsequent therapeutic interventions and had a 3-6 month follow-up. Patients were grouped as either responders (>50% seizure reduction at the 3-6 month follow-up) or non-responders.
Results: The median age of the patients included in this study was 34.0 years (interquartile range [IQR]: 27.0-45.0), and 60% were female (n = 39). We report a 31% response rate (20/65) with 6 patients achieving complete seizure freedom at the 3-6 month follow-up. Among responders, 80% (16/20) were classified with temporal lobe epilepsy. No significant differences between the demographic factors of responders and non-responders were identified. The antiseizure medications did not influence the delay of seizures. The reduction in seizure frequency was independent of the number of electrodes implanted. Moreover, 90% (18/20) of the responders received cortical stimulation during iEEG monitoring compared to 58% (26/45) of the non-responders.
Conclusions: Our data shows that one third of patients will have a temporary reduction in seizure frequency, and this phenomenon is frequently seen in patients who received cortical stimulation.
Acknowledgements
Thank you to Dr. Suller Marti for her support and guidance throughout this project. I would also like to thank the USRI program, Western University, and the Western Institute for Neuroscience for the opportunity to pursue this internship.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
Document Type
Poster
Intracranial EEG Patient Analysis: Seizure Reduction in Refractory Epilepsy Following Depth Electrode Insertion
Rationale: The implantation effect describes an immediate reduction in seizure frequency following the insertion of intracranial electrodes. There is limited information regarding which patients will experience a reduction of seizures and the reason for the implantation effect. This study focuses on describing predictor factors for the reduction in seizure frequency in patients with medically resistant epilepsy implanted with depth electrodes.
Methods: We conducted a retrospective chart review of 89 patients who underwent intracranial electroencephalography (iEEG) monitoring with depth electrodes. Sixty-five of these patients had no subsequent therapeutic interventions and had a 3-6 month follow-up. Patients were grouped as either responders (>50% seizure reduction at the 3-6 month follow-up) or non-responders.
Results: The median age of the patients included in this study was 34.0 years (interquartile range [IQR]: 27.0-45.0), and 60% were female (n = 39). We report a 31% response rate (20/65) with 6 patients achieving complete seizure freedom at the 3-6 month follow-up. Among responders, 80% (16/20) were classified with temporal lobe epilepsy. No significant differences between the demographic factors of responders and non-responders were identified. The antiseizure medications did not influence the delay of seizures. The reduction in seizure frequency was independent of the number of electrodes implanted. Moreover, 90% (18/20) of the responders received cortical stimulation during iEEG monitoring compared to 58% (26/45) of the non-responders.
Conclusions: Our data shows that one third of patients will have a temporary reduction in seizure frequency, and this phenomenon is frequently seen in patients who received cortical stimulation.