Bridging the Electroclinical Paradox to Precision Care by Elucidating Seizure Network Dynamics

Despite its long-standing reputation as one of the most surgically remediable epilepsy syndromes in adults, mesial temporal lobe epilepsy (MTLE) remains a persistent challenge in presurgical evaluation.This difficulty arises in part from the frequent dissociation between electrographic and clinical seizure manifestations, which resists explanation by a single, uniform network model.Rather, accumulating evidence suggests that MTLE comprises multiple, heterogeneous seizure networks.In this context, Bae and colleagues, in this issue of the Journal of Clinical Neurology, offer an important conceptual advance by demonstrating that distinct seizure propagation dynamics give rise to clinically recognizable electroclinical phenotypes in MTLE. 1 A persistent challenge in presurgical evaluation has been the so-called "electroclinical paradox, " in which the onset of abnormalities on scalp electroencephalography (EEG) and the emergence of clinical seizure manifestations are temporally dissociated.Some patients exhibit clear rhythmic EEG changes well before symptom onset, whereas others develop overt clinical semiology while scalp EEG findings remain subtle or delayed.Traditionally viewed as a technical limitation of scalp EEG, this electroclinical discordance may instead reflect a fundamental clue to underlying seizure network architecture.2,3 Building on this concept, Bae and colleagues propose that the electroclinical paradox arises from intrinsic differences in seizure propagation dynamics rather than from limitations of scalp recording alone.By analyzing a rigorously defined cohort of drug-resistant MTLE patients who achieved Engel Class I outcomes following stereo-EEG (SEEG)-guided surgery, the authors identified two principal phenotypes: an EEG-first profile, in which rhythmic electrophysiological changes precede clinical onset, and a Clinical-first profile, in which clinical semiology arises before prominent scalp EEG changes. 1 These phenotypes exhibited distinct temporal and electrophysiological signatures.EEGfirst seizures were characterized by relatively stereotyped rhythmic theta activity on scalp EEG and mesial low-voltage fast activity on SEEG, consistent with classical hippocampal network onset.4 In contrast, Clinical-first seizures showed more heterogeneous scalp patterns and appeared to recruit broader posterior mesial or insular networks, suggesting more rapid and distributed propagation. 1 Together, these findings support the view that MTLE encompasses divergent network phenotypes operating within a shared temporal lobe architecture.5 Notably, the study also provides clinically relevant insight into structural co-pathology.The authors report that 100% of patients in the EEG-first phenotype exhibited dual pathology, namely hippocampal sclerosis coexisting with focal cortical dysplasia type IIIa, suggesting that the presence of neocortical dysplastic substrates may modulate seizure propagation dynamics and offer an additional electroclinical clue for identifying such cases during presurgical assessment. 1 Importantly, this framework carries practical implications for clinical decision-making.Phenotype recognition may help stratify patients prior to invasive monitoring and guide tailored SEEG implantation strategies, particularly in cases where early