Overlapping Onset of Spike and Ripple Propagations is a More Specific Biomarker of the Epileptogenic Zone Than Fast Ripples
Abstract number :
3.108
Submission category :
2. Translational Research / 2C. Biomarkers
Year :
2021
Submission ID :
1826109
Source :
www.aesnet.org
Presentation date :
12/6/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:52 AM
Authors :
Saeed Jahromi, Ms - the University of Texas at Arlington; Margherita Matarrese - Unit of Non-Linear Physics and Mathematical Modeling, Engineering Department, Università Campus Bio-Medico di Roma, Rome, Italy; Lorenzo Fabbri - Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA.; Eleonora Tamilia - Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA.; M Scott Perry - Jane and John Justin Neurosciences Center, Cook Children’s Health Care System, Fort Worth, TX, USA.; Joseph R madsen - Division of Epilepsy Surgery, Department of Neurosurgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA.; Phillip L Pearl - Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA.; Christos papadelis - Jane and John Justin Neurosciences Center, Cook Children’s Health Care System, Fort Worth, TX, USA.
Rationale: Various interictal biomarkers have been proposed to delineate the epileptogenic zone (ΕΖ) in children with drug resistant epilepsy (DRE). Spikes and ripples suffer from low specificity, but they can be seen in many patients. Fast ripples are more focal and specific to the EZ but may not be sampled with conventional intracranial EEG (iEEG) macroelectrodes. Previous studies have shown that spikes and ripples propagate across large brain areas, and that the onsets of these propagations are more specific biomarkers than areas of spread. Here, we tested the hypothesis that the overlapping onset of spike and ripple propagations is a more specific biomarker than fast ripples, and that this biomarker can be seen in several patients with DRE in contrast to fast ripples.
Methods: We analyzed iEEG recordings from 29 pediatric patients with successful epilepsy surgery, (Engel 1, ≥1-year follow-up). For each patient, we detected temporal propagations of spikes (SP) (1-70 Hz), ripples (RP) (80-250 Hz), and fast ripples (FRP) (250-500 Hz) (Fig. 1A) using an in-house automatic algorithm. We then ranked and sorted the iEEG electrodes according to their timing occurrence in each propagation category. The first 25% of sorted electrodes were considered as onset and the remaining as spread. We estimated the sensitivity and specificity of onset, spread, and entire zone of propagation for each category in predicting resection, and compared them to the overlapping onset of spike and ripple propagations (OSRP) (Fig. 1B). We also compared the sensitivity and specificity of the onset of fast ripple propagations, all fast ripples, and the overlapping onset of spike and ripple propagations among all patients.
Results: We detected spikes and ripples in all 29 patients, and fast ripples in 7 patients. Spikes and ripples were propagating in all patients. Fast ripples were propagating in 6 patients. Spike and ripple onset was overlapping in all 29 patients. Spike, ripple, and fast ripple propagations had an average duration of 28.3±24.3, 38.7±37, and 25±14 ms, respectively. The onset of spike and ripple propagations (but not fast ripples) showed higher specificity to the EZ compared to the corresponding areas of spread (p< 0.05). The overlapping onset of spike and ripple propagations showed higher specificity to predict resection compared to the onset (or spread) of spikes and ripples (but not fast ripple) propagations (p< 0.01) (Fig. 2A-C). Also, the overlapping onset of spike and ripple propagations was more specific in predicting resection compared to all fast ripples (p< 0.01) (Fig. 2D).
Translational Research