Orbitofrontal epilepsy: distinct neuronal networks underlying electroclinical subtypes and surgical outcomes

OBJECTIVEThe aim of this study was to characterize the clinical and electrophysiological findings of epilepsy originating from the orbitofrontal cortex (OFC) as well as its surgical outcomes.METHODSThe authors retrospectively reviewed 27 consecutive cases of patients with drug-resistant orbitofrontal epilepsy (OFE) who underwent tailored resective surgery after a detailed presurgical workup. Demographic features, seizure semiology, imaging characteristics, resection site, pathological results, and surgical outcomes were analyzed. Patients were categorized according to semiology. The underlying neural network was further explored through quantitative FDG-PET and ictal stereo-electroencephalography (SEEG) analysis at the group level. FDG-PET studies between the semiology group and the control group were compared using a voxel-based independent t-test. Ictal SEEG was quantified by calculating the energy ratio (ER) of high- and low-frequency bands. An ER comparison between the anterior cingulate cortex (ACC) and the amygdala was performed to differentiate seizure spreading patterns in groups with different semiology.RESULTSScalp electroencephalography (EEG) and MRI were inconclusive to a large extent. Patients were categorized into the following 3 semiology groups: the frontal group (n = 14), which included patients with hyperactive automatisms with agitated movements; the temporal group (n = 11), which included patients with oroalimentary or manual automatisms; and the other group (n = 2), which included patients with none of the abovementioned or indistinguishable manifestations. Patients in the frontal and temporal groups (n = 23) or in the frontal group only (n = 14) demonstrated significant hypometabolism mainly across the ipsilateral OFC, ACC, and anterior insula (AI), while patients in the temporal group (n = 9) had hypometabolism only in the OFC and AI. The ER results (n = 15) suggested distinct propagation pathways that allowed us to differentiate between the frontal and temporal groups. Pathologies included focal cortical dysplasia, dysembryoplastic neuroepithelial tumor, cavernous malformation, glial scar, and nonspecific findings. At a minimum follow-up of 12 months, 19 patients (70.4%) were seizure free, and Engel class II, III, and IV outcomes were observed in 4 patients (14.8%), 3 patients (11.1%), and 1 patient (3.7%), respectively.CONCLUSIONSThe diagnosis of OFE requires careful presurgical evaluation. Based on their electrophysiological and metabolic evidence, the authors propose that varied semiological patterns could be explained by the extent of involvement of a network that includes at least the OFC, ACC, AI, and temporal lobe. Tailored resections for OFE may lead to a good overall outcome.

Representation of the temporal code of the national linguistic culture in the naive (pre-scientific) worldview

Time is not only a form of matter existence, a fourth coordinate, but also a category of linguistic culture, a phenomenon of a specific conceptual worldview. The present study aims to examine the linguistic and worldview phenomena which have specific linguocultural features, in particular, the temporal code which reveals a system of beliefs about time characteristic for the speakers of the Ukrainian language. The article describes the results of the reconstruction of a temporal fragment from a pre-scientific worldview. The study is based on the semasiological procedure of field modelling as well as etymological, component and syntaxeme analyses. It relies on the knowledge about word origin in the temporal group as well as about phraseological units containing words with the central seme of time and vocabulary characterized by a temporal connotation. The article elucidates two key associative vectors which guide the cognition of the temporal, namely, «time – human» and «time – environment». It provides data which reflect naïve beliefs about physics and psychology of time, coded in the Ukrainian idioms. The author examines the syntaxemic functions within phraseologisms based on temporal vocabulary. The axiological peculiarities of verbal contexts producing temporal semantics have been investigated and their utilitarian, teleological, and emotional evaluations have been described. The article offers arguments in favour of systemic connections between the temporal code of linguistic culture with the biomorphic, the objective and the somatic. The author explains that the words of the temporal group reveal deep etymological associations related to the human and the environment. In some Ukrainian idioms, the vocabulary bulk with the central seme of time is related to beliefs about mythical creatures. Due to this, such vocabulary bulk within the structure of phraseologisms mainly performs the function of the subject of action and the locative. Verbal contexts in which this vocabulary with temporal connotation is employed generate primarily negative utilitarian, teleological, and emotional evaluations. The vocabulary bulk with the semantics of time has no material denotation, and the realization of the temporal code of linguistic culture is systematically linked to the biomorphic, the somatic and the substantive.