Interictal epileptiform discharges are involved in momentary lapses of attention in children with epilepsy

Abstract Objective Attention impairments are common in children with epilepsy and widely impact their quality of life. Interictal epileptiform discharges (IED) may induce subtle dysfunctions of various cognitive processes, but data regarding the impact of IED on attention remain limited. The objective of the present study was to evaluate the impact of IED on continuous undivided attention in children with epilepsy, controlling for the number of treatments, type of epilepsy, frequency of seizures in the last year, age at onset, and comorbid attention disorder. Methods Using a computerized attention test synchronized with the electroencephalogram (EEG) in 119 children with diverse epilepsy syndromes, behavioral (reaction time [RT], errors, attention stability over time) and electrophysiological measures related to attentional engagement (event-related potential [ERP] in parietal electrodes) were collected. The cumulative impact of IED was evaluated using multivariate models controlling for epilepsy-related factors. The transient impact of IED was assessed by comparing responses in trials with and without IED. Results IED induced attention fluctuations independently from other epilepsy-related factors. In terms of cumulative impact, a higher quantity of IED was associated with a poorer attentional performance over the entire task. In terms of transient impact, trials disrupted by IED were characterized by longer RT and a lower amplitude of the parietal ERP, extending over a long-time window that included attentional processing (P300). Significance These results highlight the deleterious effect of IED on attention, at both behavioral and electrophysiological levels, independently of other epilepsy-related features. This work provides evidence that IED induce subtle attentional deficits and could be considered as biomarkers of abnormal brain function. Key points A higher quantity of IED was associated with poorer attentional performance, irrespective of other epilepsy-related features. IED promote transient cognitive impairment: trials with IED are characterized by increased RTs and a lower amplitude of the parietal ERP. EEG-synchronized attentional tasks are needed to assess subtle deficits in patients with epilepsy.