Prolonged epileptic discharges predict seizure recurrence in JME: Insights from prolonged ambulatory EEG

Abstract

Objective: Markers of seizure recurrence are needed to personalize antiseizure medication (ASM) therapy. In the clinical practice, EEG features are considered to be related to the risk of seizure recurrence for genetic generalized epilepsies (GGE).However, to our knowledge, there are no studies analyzing systematically specific EEG features as indices of ASM efficacy in GGE. In this study, we aimed at identifying EEG indicators of ASM responsiveness in Juvenile Myoclonic Epilepsy (JME), which, among GGE, is characterized by specific electroclinical features. Methods: We compared the features of prolonged ambulatory EEG (paEEG, 22 h of recording) of JME patients experiencing seizure recurrence within a year ("cases") after EEG recording, with those of patients with sustained seizure freedom for at least 1 year after EEG ("controls"). We included only EEG recordings of patients who had maintained the same ASM regimen (dosage and type) throughout the whole time period from the EEG recording up to the outcome events (which was seizure recurrence for the "cases", or 1-year seizure freedom for "controls"). As predictors, we evaluated the total number, frequency, mean and maximum duration of epileptiform discharges (EDs) and spike density (i.e. total EDs duration/artifact-free EEG duration) recorded during the paEEG. The same indexes were assessed also in standard EEG (stEEG), including activation methods. Results: Both the maximum length and the mean duration of EDs recorded during paEEG significantly differed between cases and controls; when combined in a binary logistic regression model, the maximum length of EDs emerged as the only valid predictor. A cut-off of EDs duration of 2.68 seconds discriminated between cases and controls with a 100% specificity and a 93% sensitivity. The same indexes collected during stEEG lacked both specificity and sensitivity. Significance: The occurrence of prolonged EDs in EEG recording might represent an indicator of antiepileptic drug failure in JME patients.

Brainwaves beyond diagnosis: Wider applications of electroencephalography in idiopathic generalized epilepsy

“…A more recent study took a step further to investigate different qualities of EDs associated with seizure relapse following ASM withdrawal. 49 The authors retrospectively analyzed 32 prolonged (22-h) ambulatory EEG recordings from 26 adults with JME to evaluate the predictive value of the total number, frequency, spike density, and mean/ maximum duration of EDs. In the multivariate analysis, the maximum length of ED paroxysm emerged as the only significant marker, with ≥2.68s duration predicting seizure recurrence (specificity = 100%, sensitivity = 93%).…”

“…In the multivariate analysis, the maximum length of ED paroxysm emerged as the only significant marker, with ≥2.68s duration predicting seizure recurrence (specificity = 100%, sensitivity = 93%). 49…”

“…However, the syndromic breakdown of this outcome is not provided in the publication. A more recent study took a step further to investigate different qualities of EDs associated with seizure relapse following ASM withdrawal 49 …”

Interictal epileptiform discharges as a predictive biomarker for recurrence of poststroke epilepsy

“… 29 In patients with juvenile myoclonic epilepsy, the maximum duration of epileptic discharge sequences is considered an indicator of seizure recurrence. 30 In patients with ischaemic stroke, sharp waves/spikes on follow-up EEG after acute symptomatic seizures positively correlate with seizure recurrence risk. 23 This research identified IEDs as a risk indicator of seizure recurrence in two PSE cohorts (both n = 187).…”

EEG Markers of Treatment Resistance in Idiopathic Generalized Epilepsy: From Standard EEG Findings to Advanced Signal Analysis

“…Moreover, the study setting in a tertiary adult epilepsy center and the heterogeneity of the 24-h EEG recording delay from epilepsy diagnosis further limited the generalizability of this study’s findings. The prognostic significance of prolonged epileptiform EEG runs in the prediction of seizure remission was recently supported by the results of a study in JME patients, in which ED duration longer than 2.6 s correctly identified patients with seizure relapse within 12 months after paEEG [ 65 ].…”