Symptomatogenic zone and network of oroalimentary automatisms in mesial temporal lobe epilepsy

Abstract

Abstract Objective Oroalimentary automatisms ( OAA s) are common clinical manifestations of medial temporal lobe epilepsy. Nevertheless, the location of the symptomatogenic zone of OAA s remains unclear. The generation mechanism of OAA s also has not been clarified. We attempt to explain these problems by analyzing interictal [ 18 F]‐fluorodeoxyglucose positron emission tomography ( 18 FDG ‐ PET) imaging and ictal stereo‐electroencephalography ( SEEG ) recordings in patients with medial temporal lobe epilepsy. Methods Fifty‐seven patients with mesial temporal lobe epilepsy were analyzed retrospectively. All underwent anterior temporal lobectomy ( ATL ) and were seizure‐free. The patients were divided into OAA (+) and OAA (−) groups according to the occurrence of consistent stereotyped OAA s. The interictal PET data were compared with those of 18 healthy controls and were then compared between groups using statistical parametric mapping ( SPM ). Functional connectivity using linear regression analysis was performed between the target brain regions. To clarify the network of OAA s, ictal epileptogenicity index ( EI ) values, and the nonlinear correlation method h 2 were performed with SEEG on patients. Results Compared to OAA s (−), the rolandic operculum was the only area with significant differences. Hippocampus and rolandic operculum showed significant correlations in the OAA (+) group (y = 0.758x+0.470, R 2 = 0.456, P = 0.000). No correlation was found in the OAA (−) group ( P = 0.486). The EI values of the OAA (+) group (median 0.20) were significantly higher ( P < 0.0001) than those of the OAA (−) group (median 0). The h 2 in the OAA (+) group ( h 2 = 0.23 ± 0.13) showed stronger functional connectivity ( t = 6.166, P < 0.0001) than that of the OAA (−) group ( h 2 = 0.08 ± 0.05). Significance The rolandic operculum is most likely to be the symptomatogenic zone of OAA s. In medial temporal lobe epilepsy, unilateral functional connection from the hippocampus to the rolandic operculum during seizure onset is the basis for the generation of OAA s.