Travelling waves reveal a dynamic seizure source in human focal epilepsy.

Treatment of patients with drug-resistant focal epilepsy relies upon accurate seizure localization. Ictal activity captured by intracranial EEG has traditionally been interpreted to suggest that the underlying cortex is actively involved in seizures. Here, we hypothesize that such activity instead reflects propagated activity from a relatively focal seizure source, even during later time points when ictal activity is more widespread. We used the time differences observed between ictal discharges in adjacent electrodes to estimate the location of the hypothesized focal source and demonstrated that the seizure source, localized in this manner, closely matches the clinically and neurophysiologically determined brain region giving rise to seizures. Moreover, we determined this focal source to be a dynamic entity that moves and evolves over the time course of a seizure. Our results offer an interpretation of ictal activity observed by intracranial EEG that challenges the traditional conceptualization of the seizure source.

Work, Parenting, and Well-being: An International Survey of Neurologists During the COVID-19 Pandemic.

Background and Objectives: COVID-19 reframed the relationship between work and home and, in general, made both more difficult-especially for parents. We hypothesized that, among neurologists, the effects of the pandemic on productivity and on well-being would be greater on those with children than on those without children and that the effects would be greater on women with children than on men with children. Methods: We conducted an international electronic survey launched by the Practice Current section of the American Academy of Neurology. The survey included questions on demographics (self-identified gender, number of children and elderly dependents, childcare support, and country and state when applicable), workflow changes because of COVID-19, impacted domains, and productivity and well-being using the Likert scale. Counts are presented as descriptive statistics. Statistical analysis was performed using Mann-Whitney U and Kruskal-Wallis tests. Results: We collected 243 fully completed surveys from providers in all continents with high representation of the United States (76%), providers who identified as women (71.6%), and neurologists with children (91%) among respondents. A majority worked remotely (28% fully, 43% mix). Neurologists reported decreased academic productivity (72%), work benefits (65%), and time for writing (48%). These findings were more prominent in respondents with children and among women practicing outside of the United States. Increased pressure from productivity expectations and lack of time for family were reported by 47% and 41% of respondents, respectively. Discussion: The disruption from the COVID-19 pandemic affected academic productivity and decreased the well-being of neurologists in general and of neurologists with children more drastically. This could potentially hinder the promotion and retention of junior neurologists who were juggling life and work during the pandemic outbreak and its recurrent surges.

Lateralization of interictal temporal lobe hypoperfusion in lesional and non-lesional temporal lobe epilepsy using arterial spin labeling MRI.

PURPOSE: Non-invasive imaging studies play a critical role in the presurgical evaluation of patients with drug-resistant temporal lobe epilepsy (TLE), particularly in helping to lateralize the seizure focus. Arterial Spin Labeling (ASL) MRI has been widely used to non-invasively study cerebral blood flow (CBF), with somewhat variable interictal alterations reported in TLE. Here, we compare temporal lobe subregional interictal perfusion and symmetry in lesional (MRI+) and non-lesional (MRI-) TLE compared to healthy volunteers (HVs). METHODS: Twenty TLE patients (9 MRI+, 11 MRI-) and 14 HVs under went 3 T Pseudo-Continuous ASL MRI through an epilepsy imaging research protocol at the NIH Clinical Center. We compared normalized CBF and absolute asymmetry indices in multiple temporal lobe subregions. RESULTS: Compared to HVs, both MRI+ and MRI- TLE groups demonstrated significant ipsilateral mesial and lateral temporal hypoperfusion, specifically in the hippocampal and anterior temporal neocortical subregions, with additional hypoperfusion in the ipsilateral parahippocampal gyrus in the MRI+ and contralateral hippocampus in the MRI- TLE groups. Contralateral to the seizure focus, there was significant relative hypoperfusion in multiple subregions in the MRI- compared to the MRI+ TLE groups. The MRI+ group therefore had significantly greater asymmetry across multiple temporal subregions compared to the MRI- TLE and HV groups. No significant differences in asymmetry were found between the MRI- TLE and HV groups. CONCLUSION: We found a similar extent of interictal ipsilateral temporal hypoperfusion in MRI+ and MRI- TLE. However, significantly increased asymmetries were found only in the MRI+ group due to differences in perfusion contralateral to the seizure focus between the patient groups. The lack of asymmetry in the MRI- group may negatively impact the utility of interictal ASL for seizure focus lateralization in this patient population.