From nocturnal frontal lobe epilepsy to Sleep-Related Hypermotor Epilepsy: A 35-year diagnostic challenge

Abstract

Nocturnal frontal lobe epilepsy (NFLE) is a focal epilepsy with seizures arising mainly during sleep and characterized by complex, often bizarre, motor behavior or sustained dystonic posturing. First described in 1981, it was initially considered a motor disorder of sleep and was named nocturnal paroxysmal dystonia (NPD). The unusual seizure semiology, onset during sleep, and often uninformative scalp EEG and brain MRI make it difficult to distinguish NPD attacks from other non-epileptic nocturnal paroxysmal events, namely parasomnias. The long-debated epileptic origin of the condition was finally demonstrated in 1990 and the term NFLE introduced. Even though many aspects of parasomnias and NFLE have been clarified in the last two decades, the differential diagnosis remains a challenge for clinicians. To address controversial issues and define the diagnostic criteria for NFLE, a Consensus Conference was held in Bologna, Italy in 2014. Major points of agreement emerged on: (i) the relationship of the seizures with sleep and not with the circadian pattern of seizure occurrence; (ii) the possible extrafrontal origin of hypermotor seizures, without substantial differences in seizure semiology. In the wake of the Consensus, the syndrome was renamed Sleep-Related Hypermotor Epilepsy (SHE).

Sleep and Epilepsy Link by Plasticity

“…The seizure-symptoms of NFLE are consistent with the spectrum of variable degree arousals: simple, seemingly spontaneous fragments of microarousal-related behaviors, arousal, frenetic panic and hypermotor agitation, even movement storms with autonomic and emotional expressions of alarm and consistent EEG/EMG and behavioral signs. The description is “hypermotor seizures” ( 92 , 93 ).…”

Sleep Related Epilepsy and Pharmacotherapy: An Insight

“…Medial temporal lobe regions were shown more likely to manifest spike production or propagation during NREM sleep stage compared to other brain regions (Lambert et al, 2018 ). Sleep-related epilepsy is often misdiagnosed as sleep disorders (Tinuper and Bisulli, 2017 ), especially in cases where the seizures manifest exclusively during sleep. Over the past decade, the discovery of numerous pre-disposing genes and availability of advanced diagnostic tools have shed more light in understanding the nature of sleep-related epilepsy.…”

Abnormal behaviors during sleep from the viewpoint of sleep epileptology: current and future perspectives on diagnosis

“…At a Consensus Conference held in Bologna, Italy in 2014, NFLE was renamed sleep-related hypermotor epilepsy (SHE), based on three critical issues justifying the renaming (Tinuper et al 2016;Tinuper and Bisulli 2017). First, the term nocturnal was considered misleading because it implies a chronobiological pattern of seizure occurrence, whereas evidence indicates that occurrence in sleep is the most important characteristic rather than the time of day.…”

“…2Video-documented (clinical), which involves a high quality video recording of at least one (but preferably two) stereotyped episodes. (3) Video-EEG-documented (confirmed), which requires the V-PSG recording of at least one but preferably two stereotyped events with documented ictal discharge or interictal epileptiform abnormalities (Tinuper et al 2016;Tinuper and Bisulli 2017).…”