Intraoperative Electrocorticography in Awake Brain Surgery: Comparing Three Electrode Configurations for Detecting Stimulus-induced and Spontaneous Epileptiform Activity
Brin Freund1, Adrian Safa1, Alina Ivaniuk1, Anahita Jafari1, valerie davis1, David Sabsevitz1, Anteneh Feyissa2, Seyed Mirsattari2, Sanjeet Grewal1, Kaisorn Chaichana1, Alfredo Quinones-Hinojosa1, William Tatum2
1Mayo Clinic Florida, 2Mayo Clinic
Objective:
To compare three electrode designs—novel 22-contact circular grid, standard 6-contact strip, and standard high-density (HD) grid between 32 and 64 contacts—for the detection of epileptiform activity during awake craniotomy with electrocorticography (ECoG).
Background:
Electrode size and density are important in determining sensitivity in detecting epileptiform activity but electrode array may also be an important factor in considering the utility of ECoG during awake craniotomy and functional brain mapping (FBM).
Design/Methods:
This study included patients who underwent FBM with and without direct electrical stimulation (DES) during awake craniotomy with ECoG. Demographic, clinical, and ECoG data were collected.
Results:
A total of 194 patients were included, with 264 instances of electrode use: 113 circular grid, 96 strip electrode, and 55 HD grid. HD grid (15%) was used less to record ECoG during DES than circular grid (80%, p<0.001) and strip electrodes (69%, p<0.001). Sporadic interictal epileptiform activity was better detected with circular (45%, p<0.001) and HD grids (40%, p=0.006) compared to strip electrode (16%). Spontaneous seizures were recorded more frequently with circular grid (16%, p=0.018) compared to strip (9.4%) and HD grid (1.8%). Afterdischarges were better detected by circular and HD grids (combined) compared to strip electrode (67% vs. 48%, p=0.024), at lower median stimulation intensity (3 mA vs. 5 mA, p<0.001). Multivariable analyses demonstrated circular grid (p<0.001) to be more sensitive in detecting spontaneous epileptiform activity than strip and HD grid electrodes, and both grids combined (circular and HD) to be better in recording stimulus-induced epileptiform activity than the strip electrode (p=0.01).
Conclusions:
This study demonstrates higher rate of detection of epileptiform activity with circular and standard HD grids compared to strip electrode. Standard HD grid was used less during electrical stimulation and FBM, demonstrating importance of both the number of contacts and array when considering optimal conditions for ECoG during awake craniotomy and FBM.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.