Francesca Pizzo1, Nicolas Roehri2, Bernard Giusiano2, Stanislas Lagarde2, Romain Carron2, Didier Scavarda2, Aileen McGonigal2, Cristina Filipescu2, Isabelle Lambert2, Francesca Bonini2, Agnes Trebuchon2, Christian-George Bénar2, Fabrice Bartolomei1. 1. From the Epileptology Department (F.P., S.L., A.M., I.L., F. Bonini, A.T., F. Bartolomei), Functional and Stereotactic Neurosurgery (R.C.), and Pediatric Neurosurgery (D.S.), APHM, Timone Hospital, Institut de Neurosciences des Systèmes (F.P., N.R., B.G., S.L., R.C., D.S., A.M., I.L., F. Bonini, A.T., C.-G.B, F. Bartolomei), INSERM, Aix Marseille Universite; and Psychiatrie et Neurosciences (C.F.), GHU Paris, St Anne, Paris. francesca.pizzo@ap-hm.fr fabrice.bartolomei@ap-hm.fr. 2. From the Epileptology Department (F.P., S.L., A.M., I.L., F. Bonini, A.T., F. Bartolomei), Functional and Stereotactic Neurosurgery (R.C.), and Pediatric Neurosurgery (D.S.), APHM, Timone Hospital, Institut de Neurosciences des Systèmes (F.P., N.R., B.G., S.L., R.C., D.S., A.M., I.L., F. Bonini, A.T., C.-G.B, F. Bartolomei), INSERM, Aix Marseille Universite; and Psychiatrie et Neurosciences (C.F.), GHU Paris, St Anne, Paris.
Abstract
OBJECTIVE: To determine the involvement of subcortical regions in human epilepsy by analyzing direct recordings from these regions during epileptic seizures using stereo-EEG (SEEG). METHODS: We studied the SEEG recordings of a large series of patients (74 patients, 157 seizures) with an electrode sampling the thalamus and in some cases also the basal ganglia (caudate nucleus, 22 patients; and putamen, 4 patients). We applied visual analysis and signal quantification methods (Epileptogenicity Index [EI]) to their ictal recordings and compared electrophysiologic with clinical data. RESULTS: We found that in 86% of patients, thalamus was involved during seizures (visual analysis) and 20% showed high values of epileptogenicity (EI >0.3). Basal ganglia may also disclose high values of epileptogenicity (9% in caudate nucleus) but to a lesser degree than thalamus (p < 0.01). We observed different seizure onset patterns including low voltage high frequency activities. We found high values of thalamic epileptogenicity in different epilepsy localizations, including opercular and motor epilepsies. We found no difference between epilepsy etiologies (cryptogenic vs malformation of cortical development, p = 0.77). Thalamic epileptogenicity was correlated with the extension of epileptogenic networks (p = 0.02, ρ 0.32). We found a significant effect (p < 0.05) of thalamic epileptogenicity regarding the postsurgical outcome (higher thalamic EI corresponding to higher probability of surgical failure). CONCLUSIONS: Thalamic involvement during seizures is common in different seizure types. The degree of thalamic epileptogenicity is a possible marker of the epileptogenic network extension and of postsurgical prognosis.
OBJECTIVE: To determine the involvement of subcortical regions in humanepilepsy by analyzing direct recordings from these regions during epileptic seizures using stereo-EEG (SEEG). METHODS: We studied the SEEG recordings of a large series of patients (74 patients, 157 seizures) with an electrode sampling the thalamus and in some cases also the basal ganglia (caudate nucleus, 22 patients; and putamen, 4 patients). We applied visual analysis and signal quantification methods (Epileptogenicity Index [EI]) to their ictal recordings and compared electrophysiologic with clinical data. RESULTS: We found that in 86% of patients, thalamus was involved during seizures (visual analysis) and 20% showed high values of epileptogenicity (EI >0.3). Basal ganglia may also disclose high values of epileptogenicity (9% in caudate nucleus) but to a lesser degree than thalamus (p < 0.01). We observed different seizure onset patterns including low voltage high frequency activities. We found high values of thalamic epileptogenicity in different epilepsy localizations, including opercular and motor epilepsies. We found no difference between epilepsy etiologies (cryptogenic vs malformation of cortical development, p = 0.77). Thalamic epileptogenicity was correlated with the extension of epileptogenic networks (p = 0.02, ρ 0.32). We found a significant effect (p < 0.05) of thalamic epileptogenicity regarding the postsurgical outcome (higher thalamic EI corresponding to higher probability of surgical failure). CONCLUSIONS: Thalamic involvement during seizures is common in different seizure types. The degree of thalamic epileptogenicity is a possible marker of the epileptogenic network extension and of postsurgical prognosis.
Authors: Wen Shi; Dana Zemel; Sudiksha Sridhar; Rebecca A Mount; R Mark Richardson; Uri T Eden; Xue Han; Mark A Kramer; Catherine J Chu Journal: Epilepsy Behav Rep Date: 2022-02-08