A cross-sectional investigation of cognition and epileptiform discharges in juvenile absence epilepsy

Abstract

Objective

Despite the prevalence of cognitive symptoms in the idiopathic generalized epilepsies (IGE), cognitive dysfunction in juvenile absence epilepsy (JAE), a common yet understudied IGE subtype, remains poorly understood. This descriptive study provides a novel, comprehensive characterization of cognitive functioning in a JAE sample and examines the relationship between cognition and 24-hour epileptiform discharge load.

Method

Forty-four individuals diagnosed with JAE underwent cognitive assessment using Woodcock Johnson III Test of Cognitive Abilities with concurrent 24-hour ambulatory EEG monitoring. Generalized epileptiform discharges of any length, and prolonged generalized discharges ≥ 3 seconds were quantified across wakefulness and sleep. The relationship between standardized cognitive scores and epileptiform discharges were assessed through regression models.

Results

Cognitive performances in overall intellectual ability, acquired comprehension- knowledge, processing speed, long-term memory storage and retrieval and executive processes were 0.63 – 1.07 standard deviation units lower in the JAE group compared to the population reference mean, adjusted for educational attainment. Prolonged discharges (≥ 3 seconds) were recorded in 20 patients (47.6%) from 42 available EEGs and were largely unreported. Duration and number of prolonged discharges was associated with reduced processing speed and long-term memory storage and retrieval.

Significance

Cognitive dysfunction is seen in patients with JAE across various cognitive abilities, including those representing more stable processes like general intellect. During 24-hour EEG, prolonged epileptiform discharges are common yet under-reported in JAE despite treatment and show moderate effects on cognitive abilities. If epileptiform burden is a modifiable predictor of cognitive dysfunction, therapeutic interventions should consider quantitative 24-hour EEG with routine neuropsychological screening. The growing recognition of the spectrum of neuropsychological comorbidities of IGE highlights the value of multidisciplinary approaches to explore the causes and consequences of cognitive deficits in epilepsy.

Authors

Anita L. Dharan, Stephen C. Bowden, Andre Peterson, Alan Lai, Udaya Seneviratne, Gabriel Dabscheck, Ewan Nurse, Amy Loughman, Nicholas Parsons, and Wendyl J. D’Souza.