Anatomo-electro-clinical characteristics of bilateral asymmetric tonic seizures originating from posterior insula: a SEEG study of 7 patients
10.3760/cma.j.cn115354-20250227-00107
- VernacularTitle:基于立体脑电图的岛后小叶起源双侧非对称强直发作的解剖-电-临床特征：7例病例分析
- Author:
Jun ZHUANG
1
;
Lingxia FEI
1
;
Kaihui LI
1
;
Qinghua TAN
1
;
Danfang LI
1
;
Hua LI
1
;
Meiling CAI
1
Author Information
1. 广东三九脑科医院癫痫内科，广州 510510
- Publication Type:Journal Article
- Keywords:
Epilepsy;
Posterior insula;
Bilateral asymmetric tonic seizure;
Anatomo-electro-clinical correlation;
Stereo-electroencephalography;
Epileptogenic network
- From:
Chinese Journal of Neuromedicine
2025;24(4):385-391
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the epileptogenic networks of bilateral asymmetric tonic seizures (BATS) originating from the posterior insula using stereo-electroencephalography (SEEG).Methods:A retrospective analysis was performed. Among the epilepsy patients who underwent preoperative assessment and SEEG monitoring in the Epilepsy Department of Guangdong Sanjiu Brain Hospital from January 1, 2015 to July 1, 2024, 7 patients with insular epilepsy characterized by BATS originating from the posterior insula were selected based on anatomo-electro-clinical characteristics. The clinical characteristics, neuroimaging features, scalp EEG patterns, and SEEG recordings of the 7 patients were collected and analyzed. Via synchronously analyzing ictal semiology and electroanatomical propagation pathways shown by SEEG, the features of epileptogenic networks were elucidated. Results:Four patients had seizure onset from the dorsal-superior part of the left posterior insula, and 3 patients from the dorsal-superior part of the right posterior insula. The electroencephalographic characteristics of the seizure onset zones showed high consistency in these 7 patients: rhythmic spike or multiple spike discharges at the initial stage, and a low-amplitude rapid rhythm pattern subsequently. Totally, 3-10 seizures were recorded in each patient. Four patients experienced prodromal symptoms, including 3 patients with somatosensory symptoms (1 with chest and abdominal pain, 1 with contralateral facial numbness combined with throat constriction sensation, and 1 with contralateral limb numbness), and 1 patient with non-specific presentation (hugging family member before seizure). The seizure semiological evolution sequence was from prodrome to BATS, and then to secondary symptoms, with 3 patients exhibiting clustered spasms as secondary symptoms, and 4 patients showing eyelids and contralateral upper limb distal tonic-clonic manifestations as secondary symptoms. The epileptogenic networks followed a consistent pattern: the dorsal-superior part of the posterior insula leads to the middle-posterior part of the superior circular sulcus, to the ventral posterior insular and posterior circular sulcus, and then to the supplementary sensorimotor area (SSMA), and finally to the central sulcus, central region-vertex, and inferior parietal lobule. Only 2 patients had the anterior insular-involved epileptic brain networks, while the remaining 5 patients did not involve the anterior insular. During BATS, SEEG electrode contacts corresponding to the posterior insular, superior circular sulcus and SSMA exhibited low-amplitude rapid rhythm patterns.Conclusion:The seizures spread from the dorsal-superior part of the posterior insula to the middle-posterior part of the superior circular sulcus at the early stage of onset, and then connected with SSMA; these structures formed a epileptogenic brain network through abnormal synchronous discharge, which eventually led to BATS.
