Objective: To study the semiology characteristics of motor seizures of axial and shoulder girdle muscles (ASMs) by stereoelectroencephalography (SEEG) and its value in determining location of epileptogenic zone.
Methods: A total of 598 patients underwent SEEG assessment in Sanbo Brain Hospital were reviewed; 65 patients with ASMs selected. Thirteen semiology feature items were extracted according to the location and symmetry of involved axial muscles, direction of movement, etc. Seizures were grouped with items, and the k-means was used to analyze association between ASMs semiology characteristics and seizure-onset zone (SOZ).
Results: The SOZs of ASMs involved 23 combinations of seven different brain regions: 31 patients (47.7%) had one brain region, 19 (29.2%) had two, 14 (21.5%) had three, and one patient (1.5%) had four. One hundred and fifteen brain regions were analyzed. Seven brain regions accounted for a significant difference in chi-square test, χ2 = 62.79, p < 0.0001, with the highest proportion of insular and perisylvian. The k-means method identified two clusters: cluster 1 had a high degree of agreement with temporal lobe epilepsy (12/15), characterized by less shrug-like movement, later involvement of axial shoulder girdle muscles, longer duration, and lower seizure frequency; cluster 2 had a high degree of agreement with posterior cortex epilepsy (14/18), characterized by earlier involvement of axial shoulder girdle muscles, shorter duration, and higher seizure frequency. In frontal lobe, insular and perisylvian, anterior and middle cingulate gyrus, are the two categories accounted for similar proportion. Seizure-onset lateralized at the contralateral of unilateral cervical tonic, with rate of seizure-free was 73.7%.
Significance: The incidence of ASMs is high in insular and perisylvian. Unilateral cervical tonic seizures have good lateralizing value. Based on semiology characteristics, ASMs can be roughly clustered into two categories, which can only effectively distinguish the origins of temporal lobe and posterior cortex, with low discrimination for the seizure-onset of other lobes.
Keywords: SEEG; axial muscle; epileptogenic zone; motor seizures.
© 2023 International League Against Epilepsy.