Post-Ictal Sleep Changes in Human Focal Epilepsy

Bidirectional interactions between sleep, seizures, and epilepsy remain incompletely understood. Evidence from animal models and people with focal epilepsy suggest that seizures may engage mechanisms of memory consolidation to reinforce and strengthen synaptic connections within the pathological networks that generates seizures, termed seizure-related consolidation (SRC). Human studies of SRC, however, are limited by small sample size and restricted observations of post-ictal sleep. Using continuous local field potential (LFP) recordings from novel investigational devices implanted in 11 people with drug-resistant focal epilepsy living in their natural environments, we used automated methods to create accurate sleep-wake and seizure catalogs for investigating the interplay between seizures and sleep. Our findings demonstrate that post-ictal slow-wave sleep duration, slow-wave LFP spectral power and waveform slope are increased compared to inter-ictal nights without preceding seizures. The most significant changes localize to the epileptogenic networks generating the subjects habitual seizures. These results reveal parallels between SRC and physiological memory consolidation, providing new insights into the role of post-ictal sleep in epilepsy and underscoring the potential of targeting post-ictal sleep for therapeutic interventions in drug-resistant focal epilepsy.