Comparison of Guillain-Barre Syndrome Cases during and Prior to the COVID-19 Pandemic: A Multicentric Study.

BACKGROUND: Guillain-Barre syndrome (GBS) is one of the most common neurological manifestations associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Although data for a strong causal association is lacking, anecdotal reports, case series and systematic reviews linking the two have emerged in the literature. This prompted us to compare the clinical features, electrophysiology, and outcomes of GBS cases presenting during the pandemic with cases reported during a similar time period prior to the pandemic. MATERIALS AND METHODS: Prospective data of GBS cases diagnosed as per the National Institute of Neurological Disorders and Stroke (NINDS) criteria was collected for a 6-month period (July-December 2021) at three tertiary care teaching hospitals during the coronavirus pandemic and compared with retrospective records-based data of cases prior to the pandemic (January-July 2019). RESULTS: A total of 40 cases were included in the cases, out of which 17 were in the prepandemic and 23 in the postpandemic period. A total of three cases temporally related to coronavirus disease 2019 (COVID-19) infection and four cases following COVID-19 vaccination were seen in the pandemic cohort. The clinical features, electrophysiological features, and outcomes were comparable during both periods. A slightly higher rate of in-hospital complications and single mortality was reported in the postpandemic period. DISCUSSION: The number of GBS hospital admissions, clinical presentation, electrodiagnostic features, and short-term outcomes did not differ significantly between the prepandemic and postpandemic periods; a slightly higher incidence of in-hospital complications was observed during the pandemic period. How to cite this article: Panicker P, R D, V AG, et al. Comparison of Guillain-Barre Syndrome Cases during and Prior to the COVID-19 Pandemic: A Multicentric Study. J Assoc Physicians India 2023;71(9):69-71.

Analysis of spatio-temporal propagation of occipito-frontal spikes in childhood epilepsies by 3D sequential voltage mapping and dipole localization.

OBJECTIVE: We sought to study the spatio-temporal propagation of occipito-frontal spikes in childhood epilepsies by voltage mapping and dipole localization and identify types of occipito-frontal spikes based on onset, propagation, and stability of their dipoles. METHODS: Sleep EEG data of children, aged 1-14 years, with a minimum 1 h of recording from June 2018 to June 2021, were analyzed to identify occipito-frontal spikes. In total, 150 successive occipito-frontal spikes were manually selected from each EEG and using a source localization software were averaged using automated pattern matching with a threshold of 80%, and sequential 3D voltage maps of averaged spike were analyzed. Stability quotient (SQ) was calculated as the total number of averages/150. Stable dipole was defined as SQ ≥ .8. Dipole analysis was performed with principal component analysis using an age-appropriate template head model. RESULTS: Ten children with occipito-frontal spikes were identified; five with self-limited epilepsy with autonomic seizures (SeLEAS) and five with non-SeLEAS epilepsies. Three types of occipito-frontal spikes were identified: (1) narrow occipito-frontal spikes with stable dipoles seen in all five children with SeLEAS which were "apparently" synchronous and bilateral clone-like with an occipito-frontal interval of 10-30 ms and a homogeneous propagation pattern from a unilateral medial parieto-occipital region to an ipsilateral mesial frontal region; (2) wide occipito-frontal spikes with stable dipoles seen in one child with non-SeLEAS and developmental and/or epileptic encephalopathy with spike-wave activation in sleep (D/EE-SWAS) with an occipito-frontal interval of 45 ms, caused by focal spike propagation from a deeper temporal focus to ipsilateral peri-rolandic cortex; and (3) wide occipito-frontal spikes with unstable dipoles seen in four children with non-SeLEAS lesional epilepsies with an occipito-frontal latency of >50 ms and heterogeneous propagation patterns with poor intra-individual dipole stability. SIGNIFICANCE: We successfully identified different types of occipito-frontal spikes in childhood epilepsies. Although the term "occipito-frontal" is used to describe these spikes on the 10-20 EEG system, true propagation from occipital to frontal regions is not necessary. It is possible to differentiate idiopathic from symptomatic cases by analyzing the stability quotient and the occipito-frontal interval of occipito-frontal spikes.

Classification of electrical status epilepticus in sleep based on EEG patterns and spatiotemporal mapping of spikes

Objective: We firstly aimed to describe and classify EEG patterns in electrical status epilepticus in sleep (ESES), and secondly subclassify EEG patterns based on analysis of spikes using spatio-temporal mapping and electrical source analysis. Methods: Overnight EEGs (minimum: eight hours) of 30 children, aged 2-12 years, with ESES (spike-wave index: at least 50%) were selected. Average reference montage was used for dipole analysis and mapping. The location and orientation of the dipoles were determined by mapping positive and negative poles and applying the rules of mapping. The onset and propagation of the spikes and the latency between the two hemispheres (for bisynchronous spikes) were determined (based on source analysis using BESA research 7.1). Results: (1) ESES was classified as "generalised" (80%) and focal (20%) patterns; (2) the bisynchronous subtype in the "generalised" pattern was due to apparently synchronous bilateral activation of spikes (with lead-in of 20-60 ms from one hemisphere) with a tangential/oblique dipole (source analysis localised these spikes to around the peri-rolandic cortex); (3) the classic description of ESES spikes as "diffuse" spikes with bifrontal maxima is a misinterpretation using the 10-20 EEG system .Using voltage mapping and source analysis, cortical activation in the rolandic cortex was identified which imparts diffuse frontal negativity and parieto-occipital positivity; (4) ESES spikes showed intraspike and interspike dipole instability and the orientation of dipoles changed due to local spike propagation around the source and into the depth of the sulcus (which we refer to herein as "dancing dipoles"); and (5) focal ESES were classified as parietal, occipital and temporo-occipital patterns;a frontal ESES pattern was not seen. Significance: Based on detailed mapping and source analysis of ESES, we have successfully reinterpreted various misconceptions in the literature. We have simplified the interpretation of complicated EEG patterns by extracting the primary and propagated sources which aid the classification of ESES. As the dipole is always stable in self-limited childhood epilepsy with centrotemporal spikes, we believe that the phenomenon of an intrinsically unstable dipole is a reliable qualitative EEG marker of ESES.