TY - JOUR
T1 - Epileptic spasms are associated with increased stereo-electroencephalography derived functional connectivity in tuberous sclerosis complex
AU - Neal, Andrew
AU - Bouet, Romain
AU - Lagarde, Stanislas
AU - Ostrowsky-Coste, Karine
AU - Maillard, Louis
AU - Kahane, Philippe
AU - Touraine, Renaud
AU - Catenoix, Helene
AU - Montavont, Alexandra
AU - Isnard, Jean
AU - Arzimanoglou, Alexis
AU - Hermier, Marc
AU - Guenot, Marc
AU - Bartolomei, Fabrice
AU - Rheims, Sylvain
AU - Jung, Julien
N1 - Funding Information:
This study was supported by the Lyon Neuroscience Research Center. A.N. was supported by a postdoctoral research fellowship (Australia Awards Endeavor Research Fellowship).
Publisher Copyright:
© 2022 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.
PY - 2022/9
Y1 - 2022/9
N2 - Objective: Epileptic spasms (ES) are common in tuberous sclerosis complex (TSC). However, the underlying network alterations and relationship with epileptogenic tubers are poorly understood. We examined interictal functional connectivity (FC) using stereo-electroencephalography (SEEG) in patients with TSC to investigate the relationship between tubers, epileptogenicity, and ES. Methods: We analyzed 18 patients with TSC who underwent SEEG (mean age = 11.5 years). The dominant tuber (DT) was defined as the most epileptogenic tuber using the epileptogenicity index. Epileptogenic zone (EZ) organization was quantitatively separated into focal (isolated DT) and complex (all other patterns). Using a 20-min interictal recording, FC was estimated with nonlinear regression, h2. We calculated (1) intrazone FC within all sampled tubers and normal-appearing cortical zones, respectively; and (2) interzone FC involving connections between DT, other tubers, and normal cortex. The relationship between FC and (1) presence of ES as a current seizure type at the time of SEEG, (2) EZ organization, and (3) epileptogenicity was analyzed using a mixed generalized linear model. Spike rate and distance between zones were considered in the model as covariates. Results: Six patients had ES as a current seizure type at time of SEEG. ES patients had a greater number of tubers with a fluid-attenuated inversion recovery hypointense center (p <.001), and none had TSC1 mutations. The presence of ES was independently associated with increased FC within both intrazone (p =.033) and interzone (p =.011) networks. Post hoc analyses identified that increased FC was associated with ES across tuber and nontuber networks. EZ organization and epileptogenicity biomarkers were not associated with FC. Significance: Increased cortical synchrony among both tuber and nontuber networks is characteristic of patients with ES and independent of both EZ organization and tuber epileptogenicity. This further supports the prospect of FC biomarkers aiding treatment paradigms in TSC.
AB - Objective: Epileptic spasms (ES) are common in tuberous sclerosis complex (TSC). However, the underlying network alterations and relationship with epileptogenic tubers are poorly understood. We examined interictal functional connectivity (FC) using stereo-electroencephalography (SEEG) in patients with TSC to investigate the relationship between tubers, epileptogenicity, and ES. Methods: We analyzed 18 patients with TSC who underwent SEEG (mean age = 11.5 years). The dominant tuber (DT) was defined as the most epileptogenic tuber using the epileptogenicity index. Epileptogenic zone (EZ) organization was quantitatively separated into focal (isolated DT) and complex (all other patterns). Using a 20-min interictal recording, FC was estimated with nonlinear regression, h2. We calculated (1) intrazone FC within all sampled tubers and normal-appearing cortical zones, respectively; and (2) interzone FC involving connections between DT, other tubers, and normal cortex. The relationship between FC and (1) presence of ES as a current seizure type at the time of SEEG, (2) EZ organization, and (3) epileptogenicity was analyzed using a mixed generalized linear model. Spike rate and distance between zones were considered in the model as covariates. Results: Six patients had ES as a current seizure type at time of SEEG. ES patients had a greater number of tubers with a fluid-attenuated inversion recovery hypointense center (p <.001), and none had TSC1 mutations. The presence of ES was independently associated with increased FC within both intrazone (p =.033) and interzone (p =.011) networks. Post hoc analyses identified that increased FC was associated with ES across tuber and nontuber networks. EZ organization and epileptogenicity biomarkers were not associated with FC. Significance: Increased cortical synchrony among both tuber and nontuber networks is characteristic of patients with ES and independent of both EZ organization and tuber epileptogenicity. This further supports the prospect of FC biomarkers aiding treatment paradigms in TSC.
KW - epileptogenicity
KW - network
KW - stereo-EEG
KW - tubers
UR - http://www.scopus.com/inward/record.url?scp=85134658945&partnerID=8YFLogxK
U2 - 10.1111/epi.17353
DO - 10.1111/epi.17353
M3 - Article
C2 - 35775943
AN - SCOPUS:85134658945
SN - 0013-9580
SP - 2359
EP - 2370
JO - Epilepsia
JF - Epilepsia
ER -