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Summary Objective The multicenter National Infantile Spasms Consortium prospective cohort was used to compare outcomes and phenotypic features of patients with infantile spasms with and without hypsarrhythmia. Methods Patients aged 2 months to 2 years were enrolled prospectively with new-onset infantile spasms. Treatment choice and categorization of hypsarrhythmia were determined clinically at each site. Response to therapy was defined as resolution of clinical spasms (and hypsarrhythmia if present) without relapse 3 months after initiation. Results Eighty-two percent of patients had hypsarrhythmia, but this was not associated with gender, mean age, preexisting developmental delay or epilepsy, etiology, or response to first-line therapy. Infants with hypsarrhythmia were more likely to receive standard treatment (adrenocorticotropic hormone, prednisolone, or vigabatrin [odds ratio (OR) 2.6, 95% confidence interval (CI) 1.4–4.7] and preexisting epilepsy reduced the likelihood of standard treatment (OR 3.2, 95% CI 1.9–5.4). Hypsarrhythmia was not a determinant of response to treatment. A logistic regression model demonstrated that later age of onset (OR 1.09 per month, 95% CI 1.03–1.15) and absence of preexisting epilepsy (OR 1.7, 95% CI 1.06–2.81) had a small impact on the likelihood of responding to the first-line treatment. However, receiving standard first-line treatment increased the likelihood of responding dramatically: vigabatrin (OR 5.2, 95% CI 2–13.7), prednisolone (OR 8, 95% CI 3.1–20.6), and adrenocorticotropic hormone (ACTH; OR 10.2, 95% CI 4.1–25.8). Significance First-line treatment with standard therapy was by far the most important variable in determining likelihood of response to treatment of infantile spasms with or without hypsarrhythmia.

SUMMARYPurpose: To study the utility of magnetoencephalography (MEG) in patients with refractory insular epilepsy. Covered by highly functional temporal, frontal, and parietal opercula, insular-onset seizures can manifest a variety of ictal symptoms falsely leading to a diagnosis of temporal, frontal, or parietal lobe seizures. Lack of recognition of insular seizures may be responsible for some epilepsy surgery failures. Methods: We retrospectively reviewed and analyzed MEG data in 14 patients with refractory insular seizures defined through intracranial electroencephalography (EEG) or by the presence of an epileptogenic lesion in the insula with compatible seizure semiology. MEG was performed as part of the noninvasive presurgical evaluation, using a 275-channel whole head MEG system. MEG data were analyzed using a single equivalent current dipole model. MEG localization was compared to interictal positron emission tomography (PET) and ictal single photon emission computed tomography (SPECT) results and to the resection margin. Key Findings: Three patterns of MEG spike sources were observed. Seven patients showed an anterior operculoinsular clusters and two patients had a posterior operculoinsular cluster. No spikes were detected in one patient, and the remaining four patients showed a diffuse perisylvian distribution. Spike sources showed uniform orientation perpendicular to the sylvian fissure. Nine patients proceeded to insular epilepsy surgery with favorable surgical outcome. Among patients with anterior operculoinsular cluster who proceeded to have surgery, MEG provided superior information to ictal SPECT in four of six patients and to interictal PET in five of six patients. Significance: MEG is useful in identifying patients who are likely to benefit from epilepsy surgery targeting the insula, particularly if a tight dipole cluster is identified even if other noninvasive modalities fail to produce localizing results.

Summary:Purpose: Tuberous sclerosis complex (TSC) often causes medically intractable seizures. Magnetoencephalography (MEG) localizes epileptiform discharges. To evaluate the use of MEG spike sources (MEGSSs) for localizing epileptic zones in TSC patients, we characterized MEGSSs and correlated them to EEG and magnetic resonance imaging (MRI) results.Methods: We analyzed data from seven children who underwent prolonged video-EEG, MEG, and MRI. We classified MEGSSs as clusters (six or more spike sources, ≤1 cm between sources) and scatters (fewer than six spike sources regardless of distance between sources; sources with >1 cm between sources regardless of number of sources).Results: A single, unilateral cluster with additional scatters occurred in two patients; these predominantly lateralized dipoles correlated to prominent tubers on MRI and ictal/interictal EEG zones. Bilateral clusters with scatters existed in two patients; cluster locations partly overlapped multiple prominent tubers.These patients also had bilateral or diffuse interictal discharges, bilateral or generalized seizures, and changing seizure types and EEG findings. Only bilateral scatters occurred in three patients; scatters partly overlapped EEG interictal/ictal-onset regions; one patient had coexisting generalized seizures. In one patient with equally bilateral scatters, scatters overlapped a prominent tuber and interictal/ictal-onset zones in the right frontal region.Conclusions: MEG contributes to information from EEG and MRI for localizing epileptogenic zones in children with TSC. A single cluster with scatters in a unilateral hemisphere predicts a primary epileptogenic zone or hemisphere; bilateral or multiple clusters indicate bilateral primary or potential epileptogenic zones; and bilateral scatters without clusters may indicate epileptogenic zones that are hidden within extensive areas of scattered MEGSSs.

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