Frequent involvement of cingulate and insulo-opercular regions in sleep-related hypermotor epilepsy: A multimodal presurgical study.

OBJECTIVE

Sleep-related hypermotor epilepsy (SHE) is classically considered a frontal lobe epilepsy; however, accumulating evidence suggests that hypermotor seizures may arise from multiple frontal and extrafrontal regions. We characterized the anatomical distribution of best available localizations in patients with SHE using multimodal presurgical data.

METHODS

We retrospectively analyzed 17 patients with clinically diagnosed SHE who underwent comprehensive evaluation, including long-term video-electroencephalographic (EEG) monitoring, 3-T high-resolution magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose positron emission tomography, and, where indicated, magnetoencephalography, stereo-EEG (SEEG), and surgical assessment. Best available anatomical localizations were assigned using a hierarchical multimodal framework incorporating surgical, SEEG, and concordant noninvasive findings. Their anatomical distribution was subsequently assessed at the cohort level.

RESULTS

Sixteen patients (94.1%) had an assigned best available localization. Cingulate or insulo-opercular regions were involved in 11 of 16 patients (68.8%), whereas the remaining cases were localized to other frontal regions. In a sensitivity analysis restricted to 10 patients with SEEG-defined and/or surgically supported localizations, six involved cingulate or insulo-opercular regions. All patients were MRI-negative. In contrast, MRI-positron emission tomography fusion provided regionally informative anatomical findings in 16 of 17 cases and contributed to multimodal localization. Interictal epileptiform discharges were identified in 15 patients, whereas regionally informative ictal scalp EEG patterns were observed in eight; ictal interpretation was frequently limited by rapid propagation, movement-related artifacts, and delayed EEG onset. Focal cortical dysplasia-related histopathological findings were identified in five of seven resected specimens, whereas interpretation in two was limited by prior thermocoagulation.

SIGNIFICANCE: These descriptive findings indicate that cingulate and insulo-opercular regions were frequently represented among the identified localizations in this presurgical cohort. Multimodal evaluation integrating electroclinical, imaging, and invasive findings may support presurgical localization in MRI-negative SHE.