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Abstract Methods to quantify cortical hyperexcitability are of enormous interest for mapping epileptic networks in patients with focal epilepsy. We hypothesize that, in the resting state, cortical hyperexcitability increases firing-rate correlations between neuronal populations within seizure onset zones (SOZs). This hypothesis predicts that in the gamma frequency band (40–200 Hz), amplitude envelope correlations (AECs), a relatively straightforward measure of functional connectivity, should be elevated within SOZs compared to other areas. To test this prediction, we analyzed archived samples of interictal electrocorticographic (ECoG) signals recorded from patients who became seizure-free after surgery targeting SOZs identified by multiday intracranial recordings. We show that in the gamma band, AECs between nodes within SOZs are markedly elevated relative to those elsewhere. AEC-based node strength, eigencentrality, and clustering coefficient are also robustly increased within the SOZ with maxima in the low-gamma band (permutation test Z-scores > 8) and yield moderate discriminability of the SOZ using ROC analysis (maximal mean AUC ~ 0.73). By contrast to AECs, phase locking values (PLVs), a measure of narrow-band phase coupling across sites, and PLV-based graph metrics discriminate the seizure onset nodes weakly. Our results suggest that gamma band AECs may provide a clinically useful marker of cortical hyperexcitability in focal epilepsy.

Gelastic seizures (GS) are typically associated with hypothalamic hamartomas and present during childhood. However it is now known that GS can be found in focal epilepsies arising from other regions in the brain, including mesial and neocortical frontal, temporal and parietal regions. GS have rarely been described as the presenting manifestation of New Onset Refractory Status Epilepticus (NORSE). In this article we describe a previously healthy 3-year-old who presented with an explosive onset of GS that were refractory to multiple anti-seizure medications. These seizures arose from the right frontal region. An extensive metabolic and immunological evaluation was negative. Her brain magnetic resonance imaging (MRI) was negative, however the Positron Emission Tomography (PET) scan showed a hypermetabolic region in the right frontal inferior gyrus. She underwent a depth electrode evaluation that revealed a widespread irritative zone involving the PET “lesion” as well as mesial and neocortical regions in the right frontal lobe. The seizure onset zone was widespread and non-localizable. However the GS were associated with a clear ictal epileptiform discharge on invasive EEG arising from the depth of the superior frontal gyrus, which was not overlapping with the PET hypermetabolic region. She underwent a right frontal lobectomy sparing the primary motor region in the pre-central gyrus. She has remained seizure free for 15 months since. The pathological analysis showed focal cortical dysplasia type II in the region of the PET scan hypermetabolism. This case expands the clinical spectrum of GS to include cases of NORSE. Additionally the case highlights the role of resective surgery in GS presenting as NORSE and the potentially excellent outcome that can be achieved by early intervention.

Abstract Object  Anterior and anterolateral skull base approaches offer the advantages of improved visualization and minimal brain retraction for lesions involving the orbital apex, parasellar regions, and anterior and middle fossa floors. These approaches are seldom used in the pediatric population due to the perceived increase in morbidity and surgical complexity. We report the application of the previously described modified osteoplastic orbitozygomatic (OZ) craniotomy to pediatric neurosurgical cases. This approach offers a number of advantages and is technically straightforward. Materials and methods  The results from six pediatric cases are reported. Age ranged from 26 months to 15 years, with a follow-up period of 5 to 22 months. Pathology included craniopharyngioma (three), frontal epidural abscess–subdural empyema with intraorbital extension (one), hypothalamic hamartoma (one), and optic pathway glioma (one). No complications related to the surgical approach were noted. In all cases, good postoperative cosmesis was achieved with excellent realignment of the orbital rim. Temporalis muscle bulk was preserved and symmetric in all cases. Conclusion  The modified osteoplastic OZ craniotomy can be safely and effectively applied to the pediatric population. Advantages include: (1) ease of use; (2) superior exposure and therefore less brain retraction; (3) an easily replaced one-piece bone flap which obviates the need for plating–suturing at the orbital rim; (4) a vascularized bone flap less susceptible to infection; and (5) maintenance of normal temporalis muscle anatomy for improved cosmesis and function. [ABSTRACT FROM AUTHOR]