Graph index complexity as a novel surrogate marker of high frequency oscillations in delineating the seizure onset zone. Issue 1 (January 2020)

• Record Type: Journal Article
• Authors: Spring, Aaron M.; Pittman, Daniel J.; Bessemer, Robin; Federico, Paolo
• Is Part Of: Clinical neurophysiology. Volume 131:Issue 1(2020:Jan.)
• Page Start: 78
• Page End: 87
• Publication Date: 2020-01
• Subjects: EEG -- Epilepsy -- Graph index complexity -- Surrogate marker -- High frequency oscillation -- HFO; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2019.09.019
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: The uGIC is a surrogate marker of HFO activity, independent of discrete events. HFOs and the uGIC identify cortical regions that overlap with the seizure onset zone. HFOs and the uGIC have are strong positive predictors of post-surgical outcome. Abstract: Objective: To investigate the Graph Index Complexity (uGIC) as a marker of high frequency oscillatory (HFO) activity, the seizure onset zone (SOZ), and surgical outcome. Methods: The SOZ, rates of HFOs at two thresholds (broad, strict), and uGIC were determined using EEG data from 41 patients. The correlation between HFOs and uGIC were calculated. HFOs and uGIC were compared within and outside the SOZ. Postsurgical outcome was compared to the colocalization of HFOs and resected SOZ. Results: There was significant correlation between uGIC and both broad ( r = 0.69, p < 0.0005) and strict HFOs ( r = 0.48, p < 0.0005). All were significantly greater within the SOZ overall, but only in 17/41 (strict, uGIC) or 18/41 (broad) patients. HFO markers were significantly greater within the SOZ for 8/15 patients with positive postsurgical outcomes, but not for any patients with negative outcomes (0/5). Conclusion: The uGIC is a marker of HFO activity, while HFOs and uGIC are markers of the SOZ overall. Colocalization of HFOs and the SOZ has strong positive predictive value for postsurgical outcome, but poor negative predictive value. Significance: The uGIC is an objective surrogate marker of HFO activity independent of identifying discrete HFO events.