Anatomo-Electro-Clinical Features of Parietal Lobe Epilepsy: Insights From Scalp Video-Electroencephalography

Abstract

Aims: To summarize the anatomo-electro-clinical characteristics of parietal lobe epilepsy (PLE) subgroups using unsupervised cluster analysis. Methods: This retrospective cohort study included patients with drug-resistant PLE with seizure freedom after surgery and evaluated scalp video-electroencephalography (EEG) recordings from three epilepsy centers. Hierarchical cluster analysis associated interictal/ictal patterns and initial ictal semiology with anatomical subgroups. Results: We analyzed 79 interictal EEG, 141 ictal EEG, and 141 semiological patterns in 47 patients. Cluster analysis associated interictal and ictal discharges from lateral superior parietal lobule epilepsy with centroparietal region distributions on scalp EEG, whereas discharges from other subgroups involved broader regions. Cluster heatmaps of the initial ictal semiology showed: Chapeau de gendarme, affective phenomena, and forced eye deviation in intraparietal sulcus; contralateral limb tonic/clonic or akinetic, affective phenomena, and visual illusions in SPL-lateral; Chapeau de gendarme, behavioral arrest, and vestibular in parieto-occipital sulcus; behavioral arrest in angular gyrus; distal gestural automatisms and cephalic sensations in posterior cingulate; body-perception illusion and contralateral versive in supramarginal gyrus; contralateral facial tonic/clonic in parietal operculum. Conclusion: PLE subgroups exhibited distinct scalp EEG features and ictal semiology, reflecting unique propagation networks and highlighting the importance of detailed video-EEG for identifying the epileptogenic zone and guiding intracranial electrode placement.