title: Electroclinical semiology of the bilateral asymmetric tonic seizures observed in patients with supplementary sensorimotor area epilepsy confirmed by pre- and post-operative MRI.
abstract: To retrospectively reappraise characteristics of the electro-clinical seizure semiology of the bilateral asymmetric tonic seizure (BATS) in the patients with supplementary sensorimotor area (SSMA) epilepsy.
  
  
  
  From the retrospective analysis of the pre- and post-operative Magnetic Resonance Imaging (MRI) data involving 386 patients who received epilepsy surgery, 123 BATS were identified meeting the clinical criteria and included in the study. For comparison in four extremities involvement, limbs were paired and comparatively evaluated between the contralateral and ipsilateral sides, proximal and distal segments, and upper and lower limbs. For evaluation of sequential events, each tonic phase of the BATS was chronologically divided into 10 equal epochs. In each epoch, distribution of tonic events in 4 extremities and axes was visually evaluated and comparatively analyzed.
  
  
  
  Asymmetric tonic posturing was the most constant findings in 6 patients, whose upper limbs contralateral to epileptogenic cortex were kept in abduction in all 123 (100%) seizures and extension in 118 (95.9%) seizures. This type of asymmetry became visible and remained stable in the initial three epochs of the tonic phase in 107 out of 123 (87.0%) seizures. In each epoch, especially the initial one, the contralateral upper limbs were involved more frequently than those ipsilateral to the epileptogenic cortex (p < 0.05). By pairwise comparison, an earlier involvement of the contralateral side to epileptogenic cortex was visually observed in 53 out of 280 (18.9%) limb pairs, in which the ipsilateral limbs were preceded by the contralateral ones 4.6 (0.1-16.0) seconds earlier. Both of the proximal and distal segments were simultaneously involved in 260 out of 298 (87.2%) limb pairs, although the former were 4.3 (0.5-16.0) earlier than the latter in 34 out of 298 (11.4%) limb pairs.
  
  
  
  This study demonstrated that by studying the restricted epileptogenic lesion limited to pure SSMA, unilateral extension and abduction posturing in upper limb were the most prominent and valuable sign for the lesion lateralization in SSMA neurosurgery decision-making.
authors.affiliation: Department of Neurology, Fu Xing Hospital, Capital Medical University, Beijing, P. R. China.|Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, P. R. China.|Capital Medical University, Beijing, P. R. China.
authors.forename: Guilan
authors.initials: G
authors.lastname: Cai
authors.affiliation: Department of Neurology, Fu Xing Hospital, Capital Medical University, Beijing, P. R. China.|Capital Medical University, Beijing, P. R. China.|Department of Neurology and Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Beijing, P. R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Epilepsy Center, Guangdong 999 Brain Hospital, Guangzhou, Guangdong, P.R. China.
authors.forename: Xi
authors.initials: X
authors.lastname: Mei
authors.affiliation: Epilepsy Center, Guangdong 999 Brain Hospital, Guangzhou, Guangdong, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery (Ward I) and Epilepsy Center, Capital Medical University, Beijing, P. R. China.
authors.forename: Guoming
authors.initials: G
authors.lastname: Luan
authors.affiliation: Department of Neurology, Fu Xing Hospital, Capital Medical University, Beijing, P. R. China.|Capital Medical University, Beijing, P. R. China.|Department of Neurology and Epilepsy Center, Beijing Sanbo Brain Hospital, Capital Medical University, Beijing, P. R. China.|Epilepsy Center, Guangdong 999 Brain Hospital, Guangzhou, Guangdong, P.R. China.
authors.forename: Xingzhou
authors.initials: X
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D012640:Seizures / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D066191:Sensorimotor Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D055815:Young Adult
keywords: Electro-clinical semiology; Magnetic Resonance Imaging (MRI); bilateral asymmetric tonic seizure; image guidance diagnosis; supplementary sensorimotor area epilepsy (SSMA)