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OBJECTIVE Magnetoencephalography (MEG) is a useful component of the presurgical evaluation of patients with epilepsy. Due to its high spatiotemporal resolution, MEG often provides additional information to the clinician when forming hypotheses about the epileptogenic zone (EZ). Because of the increasing utilization of stereo-electroencephalography (sEEG), MEG clusters are used to guide sEEG electrode targeting with increasing frequency. However, there are no predefined features of an MEG cluster that predict ictal activity. This study aims to determine which MEG cluster characteristics are predictive of the EZ. METHODS The authors retrospectively analyzed all patients who had an MEG study (2017–2021) and underwent subsequent sEEG evaluation. MEG dipoles and sEEG electrodes were reconstructed in the same coordinate space to calculate overlap among individual contacts on electrodes and MEG clusters. MEG cluster features—including number of dipoles, proximity, angle, density, magnitude, confidence parameters, and brain region—were used to predict ictal activity in sEEG. Logistic regression was used to identify important cluster features and to train a binary classifier to predict ictal activity. RESULTS Across 40 included patients, 196 electrodes (42.2%) sampled MEG clusters. Electrodes that sampled MEG clusters had higher rates of ictal and interictal activity than those that did not sample MEG clusters (ictal 68.4% vs 39.8%, p < 0.001; interictal 71.9% vs 44.6%, p < 0.001). Logistic regression revealed that the number of dipoles (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.04–1.14, t = 3.43) and confidence volume (OR 0.02, 95% CI 0.00–0.86, t = −2.032) were predictive of ictal activity. This model was predictive of ictal activity with 77.3% accuracy (sensitivity = 80%, specificity = 74%, C-statistic = 0.81). Using only the number of dipoles had a predictive accuracy of 75%, whereas a threshold between 14 and 17 dipoles in a cluster detected ictal activity with 75.9%–85.2% sensitivity. CONCLUSIONS MEG clusters with approximately 14 or more dipoles are strong predictors of ictal activity and may be useful in the preoperative planning of sEEG implantation.

Magnetoencephalography (MEG) is a neurophysiological technique that measures the magnetic fields associated with neuronal activity in the brain. It is closely related but distinct from its counterpart electroencephalography (EEG). The first MEG was recorded more than 50 years ago and has technologically evolved over this time. It is now well established in clinical practice particularly in the field of epilepsy surgery and functional brain mapping. However, underutilization and misunderstanding of the clinical applications of MEG is a challenge to more widespread use of this technology. A fundamental understanding of the neurophysiology and physics of MEG is discussed in this article as well as practical issues related to implementation, analysis, and clinical applications. The future of MEG and some potential clinical applications are briefly reviewed.

Objective In adherence to the American Educational Research Association (AERA) guidelines on culturally informed testing practices, this paper aims to review a suggested battery of tests that is linguistically and culturally appropriate for Arabic-speaking patients and to inform the reader of the varied characteristics of the Arab world to aid in providing a culturally informed neuropsychological evaluation. Method Test instruments in Arabic were identified through systematic searches of PubMed and Google Scholar, U.S.-based website searches in Arabic and French, and in consultation with Arabic-speaking cultural brokers. Results A battery assessing cognitive domains and mood was assembled using core measures that were developed using appropriate translations, cultural adaptations, and include normative data of Arabic-speaking individuals. Supplemental measures that can be administered using translated instructions and English normative data are also identified. The rationale for test selection and clinical utility, including strengths and limitations of the proposed measures is presented. Conclusions Given the large number of Arab Americans residing in the United States combined with the dearth of Arabic speaking neuropsychologists, it is essential that non-Arabic speaking neuropsychologists educate themselves regarding culturally informed practices to better service this growing community.