Infraslow EEG Analysis Refines Epileptogenic Zone Localization
Abstract number :
686
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2020
Submission ID :
2423027
Source :
www.aesnet.org
Presentation date :
12/7/2020 9:07:12 AM
Published date :
Nov 21, 2020, 02:24 AM
Authors :
Ervin Johnson, Boston Children's Hospital; Damon Hyde - Boston Children's Hospital; Jeffrey Bolton - Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA; Scellig Stone - Boston Children's Hospital, Harvard Medical School; Alexander Rotenbe
Rationale:
Peri-ictal infraslow activity (ISA) is a poorly-understood intracranial EEG (iEEG) signal component that is not used in conventional iEEG tracing analysis. Coupled with modern visualization techniques, ISA analysis may refine and simplify epileptogenic zone (EZ) localization.
Method:
Seizures captured during stereotaxic iEEG recordings of 12 pediatric patients (6-18 years) were analyzed. ISA was extracted using a 10th order lowpass Butterworth filter with 3dB attenuation at 0.1Hz, applied to sEEG data flanking ictal onsets. Two measures, averaged across all seizures per-patient, were examined: 1) instantaneous ISA at ictal onset and 2) ISA integrated from -3 to 10 seconds post-onset. Volumetric displays of ISA measures were constructed using 3D linear interpolation onto electrode positions segmented from post-surgical CT and co-registered to preoperative MRI.
Results:
In each subject for whom ISA analysis has been completed thus far (5/12 patients), there was spatial concordance between the positive ISA field and the conventionally-identified ictal onset zone. Integrated ISA measures showed greater concordance than instantaneous measures.
Conclusion:
Peri-ictal ISA analysis may be a valuable adjunct to conventional iEEG analysis to refine EZ localization. Averaging in time and across seizures may further improve localization.
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Funding:
:NINDS R01NS088583 (AR)
Neurophysiology