Incidence of sudden unexpected death in nocturnal frontal lobe epilepsy: a cohort study

Barbara Mostacci,Francesca Bisulli,Luca Vignatelli,Laura Licchetta,Lidia Di Vito,Claudia Rinaldi,Irene Trippi,Lorenzo Ferri,Giuseppe Plazzi,Federica Provini,Paolo Tinuper

doi:10.1016/j.sleep.2014.09.019

Abstract

ObjectiveMost cases of sudden unexpected death in epilepsy (SUDEP) follow a seizure, and most deaths occur while people are in bed, presumably sleeping. Nocturnal seizures are reported to be a risk factor for SUDEP. People with nocturnal frontal lobe epilepsy (NFLE) have seizures predominantly or exclusively during sleep, often many times per night. The present study aimed to assess whether NFLE represents a high-risk condition for SUDEP. MethodsThe present study retrospectively assessed the incidence of SUDEP in a cohort reconstructed from a dedicated database of consecutive patients referred to the Epilepsy and Sleep Centres of the Institute of Neurological Sciences of Bologna from 1980 to 2012 with: (1) a diagnosis of NFLE, (2) at least 90% of seizures during sleep, and (3) at least one-year of follow-up. ResultsOne hundred and three people were included. The median time from seizure onset to last observation was 26 years, equal to a follow-up of 2789 person-years. One person died of SUDEP during the follow-up period. The incidence rate of SUDEP was 0.36 per 1000 person-years (95% CI 0.01 to 2.0). ConclusionsThe incidence of SUDEP in the participant population was not higher than the rates previously reported in prevalent epilepsy populations (0.4 to 2.3 per 1000 person-years). The low prevalence of SUDEP might reflect the low occurrence of generalised tonic-clonic seizures in people with NFLE.

Highlights

The pathogenic mechanisms underlying sudden unexpected death in epilepsy (SUDEP) have not yet been unravelled
Being found dead in bed is very common, especially in a prone position, presumably meaning that deaths occur preferentially during sleep, and the vast majority of the SUDEP cases recorded in video electroencephalography (EEG) monitoring units occurred at night [1,4,5,6,7,8,9,10]
The present research is reported following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines [12]. This retrospective cohort study was part of a larger study designed by the Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) of Neurological Sciences (INS) Bologna to investigate the features of Nocturnal frontal lobe epilepsy (NFLE)

Summary

Introduction

The pathogenic mechanisms underlying sudden unexpected death in epilepsy (SUDEP) have not yet been unravelled. Epidemiological studies have pointed to a number of risk factors and precipitating situational circumstances. A recent study suggested that a history of nocturnal seizures might be an independent risk factor for SUDEP [10]. Nocturnal frontal lobe epilepsy (NFLE) is a syndrome in which seizures occur mostly or exclusively during sleep and tend to be very frequent, occurring up to dozens of times per night [11]. Based on these assumptions, people with NFLE might be at higher risk of SUDEP. The aim of the present study was to assess the incidence of SUDEP retrospectively in a cohort of patients with NFLE, strictly defined as having more than 90% of seizures during sleep

Methods

Results

Conclusion