Insular-opercular seizures manifesting with sleep-related paroxysmal motor behaviors: A stereo-EEG study

Abstract

SUMMARYPurpose: Sleep-related complex motor seizures are a common feature of nocturnal frontal lobe epilepsy. Nevertheless, recent studies also suggest that sleeprelated hypermotor seizures can originate in the insula. The present study describes the electroclinical features of eight drug-resistant epileptic patients with insularopercular seizures manifesting with nocturnal complex motor seizures. Methods: Patients underwent a comprehensive presurgical evaluation, which included history, interictal electroencephalography (EEG), scalp video-EEG monitoring, high-resolution magnetic resonance imaging (MRI), and intracerebral recording by stereo-EEG. Key Findings: Almost all patients reported an initial sensation consisting of viscerosensitive or somatosensory symptoms. Ictal clinical signs were represented by tonicdystonic asymmetric posturing and/or hyperkinetic automatisms, including bimanual/bipedal activity and ballistic movements. Some patients exhibited dysarthric speech, hypersalivation, and apnea. Interictal and ictal EEG provided lateralizing information in the majority of patients. In three patients, MRI showed a focal anatomical abnormality in the insular-opercular region. Stereo-EEG ictal recordings demonstrated that the epileptic discharge involved simultaneously the insular cortex and the opercular region. Complex motor manifestations appeared when the ictal discharge showed an extrainsular spreading to frontomesial regions (cingulum, superior frontal gyrus, and supplementary motor area) and/or to internal and neocortical temporal lobe structures. Six patients received an insular-opercular cortical resection; three of them are seizure free (minimum follow-up 24 months) and in one a marked reduction in seizure frequency was obtained. Two patients have been operated on recently. Histology revealed a focal cortical dysplasia in three patients. One patient excluded from surgery died for sudden unexpected death in epilepsy during sleep. Significance: Our data strengthen the concept that sleeprelated complex motor attacks can originate in the insula, and provide useful electroclinical information to differentiate this localization from those with similar clinical characteristics. Furthermore, this study indicates that in these drug-resistant patients, surgical treatment represents a highly effective treatment option.

Sleep-related epileptic behaviors and non-REM-related parasomnias: Insights from stereo-EEG

“…Such studies have helped define the clinical concept of the epileptogenic network [29,30] and enabled the characterization of the frontal and extra-frontal networks involved in sleep-related epilepsies. [31][32][33][34][35][36] S-EEG has also provided novel human data on the local pathological, paraphysiological and physiological activity of different cortical and subcortical structures during the different states of the sleep-wake cycle. [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] …”

“…[32,35,106] In the future, a classification according to functional and structural connectivity [105][106][107] of the insula with its surrounding regions might provide better semiologic localization.…”

Choking in the Night Due to NFLE Seizures in a Patient with Comorbid OSA

“…4 The evolution of epileptiform discharges either in deep brain structures or structures tangential to recording scalp electrodes is deemed to account for the lack of scalp EEG abnormalities; indeed, viscerosensitive symptoms like laryngeal and throat disturbances and breathing discomfort have been reported to characterize an insular origin of seizures and to arise in response to electrical stimulation of the anterior part of the insula. 5,6 Extra-insular spreading of epileptic discharge to frontomesial regions is instead deemed to entrain complex motor manifestations. 5 …”

“…5,6 Extra-insular spreading of epileptic discharge to frontomesial regions is instead deemed to entrain complex motor manifestations. 5 …”

Physiopathogenetic Interrelationship between Nocturnal Frontal Lobe Epilepsy and NREM Arousal Parasomnias

“…Several works [16, 18, 19] have shown that extrafrontal resective surgery provides excellent results in these cases. …”