Analysis of clinical patterns and underlying epileptogenic zones of hypermotor seizures

Interictal Electroencephalography and Functional Magnetic Resonance Imaging Reveals Involvement of Mesial Anterior Frontal Structures in Patients With Hyperkinetic Semiology Type I

PURPOSE

This work investigates the presence of common anatomic regions associated with interictal activity in patients with hyperkinetic seizures type I by means of concurrent electroencephalography and functional magnetic resonance imaging.

METHODS

Six patients with hyperkinetic seizures type I were evaluated with video-EEG and electroencephalography and functional magnetic resonance imaging in the context of their presurgical evaluation. Statistical Parametric Mapping was used to perform a correlation study between the occurrence of interictal spikes on EEG and suprathreshold blood oxygen level-dependent changes in the whole-brain volume.

RESULTS

In all patients, Statistical Parametric Mapping revealed suprathreshold blood oxygen level-dependent clusters in the mesial anterior frontal areas, including the rostral mesial superior frontal gyrus and the anterior cingulate, associated with the patients' typical interictal activity.

CONCLUSIONS

The electroencephalography and functional magnetic resonance imaging findings contribute to our understanding of hyperkinetic seizures type I semiology generation and can inform stereo-EEG targeting for surgical planning in refractory cases.

Fearful arousals in sleep terrors and sleep-related hypermotor epileptic seizures may involve the salience network and the acute stress response of Cannon and Selye

We consider the disorders of arousal and sleep-related hypermotor epilepsy as genetic twin-conditions, one without, one with epilepsy. They share an augmented arousal-activity during NREM sleep with sleep-wake dissociations, culminating in sleep terrors and sleep-related hypermotor seizures with similar symptoms. The known mutations underlying the two spectra are different, but there are multifold population-genetic-, family- and even individual (the two conditions occurring in the same person) overlaps supporting common genetic roots. In the episodes of disorders of arousal, the anterior cingulate, anterior insular and pre-frontal cortices (shown to be involved in fear- and emotion processing) are activated within a sleeping brain. These regions overlap with the seizure-onset zones of successfully operated sleep-related hypermotor seizures, and notably, belong to the salience network being consistent with its hubs. The arousal-relatedness and the similar fearful confusion occurring in sleep terrors and hypermotor seizures, make them alike acute stress-responses emerging from sleep; triggered by false alarms. The activation of the anterior cingulate, prefrontal and insular regions in the episodes of both conditions, can easily mobilize the hypothalamo-pituitary-adrenal axis (preparing fight-flight responses in wakefulness); through its direct pathways to and from the salience network. This hypothesis has never been studied.

Posterior Cingulate Epilepsy: A Systematic Review

SUMMARY

In this review, authors discuss epilepsy originating from posterior cingulate regions, a challenging entity to diagnose and most likely underrecognized. A systematic review of posterior middle and posterior cingulate epilepsy cases was conducted to present a summary of current knowledge about this localization-based type of epilepsy. The literature search identified 32 articles, for a total of 69 patients (34 with posterior middle cingulate epilepsy [pMCE] and 35 with posterior cingulate epilepsy [PCE]). Most patients were children and young adults with drug-resistant lesional epilepsy with high seizure burden. In both groups, most patients reported auras, mainly sensory, but various types were reported, including autonomic, behavioral, and cognitive manifestations. Most pMCE and PCE showed motor manifestations (mainly respectively asymmetric tonic posturing and automotor features). Impaired awareness during seizures was more frequently reported in PCE than in pMCE. As for ictal scalp EEG, epileptogenic abnormalities were poorly lateralized and did not localize the seizure onset zone. An ictal temporal involvement was only observed in PCE. Interictal EEG findings were nonspecific. As for other presurgical noninvasive investigations, data are limited, and no studies have adequately assessed their value. Partly explained by our inclusion criteria, most patients underwent a surgical procedure (either lesionectomy or resection of epileptogenic zone as defined by intracranial EEG study results), which overall yielded good outcomes.

Motor seizure semiology

Motor semiology is a major component of epilepsy evaluation, which provides essential information on seizure classification and helps in seizure localization. The typical motor seizures include tonic, clonic, tonic-clonic, myoclonic, atonic, epileptic spasms, automatisms, and hyperkinetic seizures. Compared to the "positive" motor signs, negative motor phenomena, for example, atonic seizures and Todd's paralysis are also crucial in seizure analysis. Several motor signs, for example, version, unilateral dystonia, figure 4 sign, M2e sign, and asymmetric clonic ending, are commonly observed and have significant clinical value in seizure localization. The purpose of this chapter is to review the localization value and pathophysiology associated with the well-defined motor seizure semiology using updated knowledge from intracranial electroencephalographic recordings, particularly stereoelectroencephalography.

Sleep medicine: Practice, challenges and new frontiers

Sleep medicine is an ambitious cross-disciplinary challenge, requiring the mutual integration between complementary specialists in order to build a solid framework. Although knowledge in the sleep field is growing impressively thanks to technical and brain imaging support and through detailed clinic-epidemiologic observations, several topics are still dominated by outdated paradigms. In this review we explore the main novelties and gaps in the field of sleep medicine, assess the commonest sleep disturbances, provide advices for routine clinical practice and offer alternative insights and perspectives on the future of sleep research.

Patterns of hypometabolism in frontal lobe epilepsy originating in different frontal regions

Objectives

Analysis of FDG‐PET imaging commonly shows that hypometabolism extends into extra‐epileptogenic zones (extra‐EZ). This study investigates the distribution patterns of hypometabolism in frontal lobe epilepsy (FLE) originating in different frontal regions.

Methods

Sixty‐four patients with FLE were grouped by EZ localization according to Brodmann areas (BAs): Group 1 (the frontal motor and premotor area), BAs 4, 6, and 8; Group 2 (the inferior frontal gyrus and opercular area), BAs 44, 45, and 47; Group 3 (the dorsal prefrontal area), BAs 9, 10, 11, and 46; and Group 4 (the medial frontal and anterior cingulate gyrus), BAs 32 and 24. Regions of extra‐EZ hypometabolism were statistically analyzed between FLE groups and healthy controls. Correlation analysis was performed to identify relationships between the intensity of hypometabolism and clinical characteristics.

Results

Significant hypometabolism in the ipsilateral (Groups 1 and 4) or bilateral (Groups 2 and 3) anterior insulae was found. Groups 1 and 4 presented with limited distribution of extra‐EZ hypometabolism, whereas Groups 2 and 3 showed widely distributed extra‐EZ hypometabolism in the rectus gyrus, cingulate gyrus, and other regions. Additionally, the intensity of hypometabolism was correlated with epilepsy duration in Groups 2 and 3.

Conclusions

All FLE groups showed hypometabolism in the anterior insula. In addition, distinct patterns of extra‐EZ hypometabolism were identified for each FLE group. This quantitative FDG‐PET analysis expanded our understanding of the topography of epileptic networks and can guide EZ localization in the future.

Outcomes of cingulate epilepsy surgery: insights from an institutional and patient-level systematic review and meta-analysis

OBJECTIVE

Due to their deep and medial location, range of seizure semiologies, and poor localization on ictal electroencephalography (EEG), cingulate gyrus seizures can be difficult to diagnose and treat. The aim of this study was to review the available evidence on postoperative outcomes after cingulate epilepsy surgery.

METHODS

A comprehensive literature search of the PubMed/MEDLINE, Ovid Embase, Ovid Scopus, and Cochrane Library databases was conducted to identify studies that investigated postoperative outcomes of patients with cingulate epilepsy. Seizure freedom at the last follow-up (at least 12 months) was the primary endpoint. The literature search was supplemented by the authors' institutional series (4 patients).

RESULTS

Twenty-one studies were identified, yielding a total of 105 patients (68 with lesional epilepsy [65%]). Median age at surgery was 23 years, and 56% of patients were male. Median epilepsy duration was 7.5 years. Invasive EEG recording was performed on 69% of patients (53% of patients with lesional epilepsy and 97% of those with nonlesional epilepsy, p < 0.001). The most commonly resected region was the anterior cingulate (55%), followed by the posterior (17%) and middle (14%) cingulate. Lesionectomy alone was performed in 9% of patients. Additional extracingulate treatment was performed in 54% of patients (53% of patients with lesional epilepsy vs 57% of those with nonlesional epilepsy, p = 0.87). The most common pathology was cortical dysplasia (54%), followed by low-grade neoplasm (29%) and gliosis (8%). Seizure freedom was noted in 72% of patients (median follow-up 24 months). A neurological deficit was noted in 27% of patients (24% had temporary deficit), with the most common deficit being motor weakness (13%) followed by supplementary motor area syndrome (9.5%). Univariate survival analysis revealed significantly greater probability of seizure freedom in patients with lesional epilepsy (p = 0.015, log-rank test).

CONCLUSIONS

Surgical treatment of drug-resistant focal epilepsy originating from the cingulate gyrus is safe, leads to low rates of permanent adverse effects, and leads to high rates of long-term seizure freedom in carefully selected patients. These data may serve as a benchmark for surgical counseling of patients with cingulate epilepsy.

Seizure semiology: ILAE glossary of terms and their significance

This educational topical review and Task Force report aims to address learning objectives of the International League Against Epilepsy (ILAE) curriculum. We sought to extract detailed features involving semiology from video recordings and interpret semiological signs and symptoms that reflect the likely localization for focal seizures in patients with epilepsy. This glossary was developed by a working group of the ILAE Commission on Diagnostic Methods incorporating the EEG Task Force. This paper identifies commonly used terms to describe seizure semiology, provides definitions, signs and symptoms, and summarizes their clinical value in localizing and lateralizing focal seizures based on consensus in the published literature. Video-EEG examples are included to illustrate important features of semiology in patients with epilepsy.

Sleep and epilepsy: A snapshot of knowledge and future research lines

Sleep and epilepsy have a reciprocal relationship, and have been recognized as bedfellows since antiquity. However, research on this topic has made a big step forward only in recent years. In this narrative review we summarize the most stimulating discoveries and insights reached by the "European school." In particular, different aspects concerning the sleep-epilepsy interactions are analysed: (a) the effects of sleep on epilepsy; (b) the effects of epilepsy on sleep structure; (c) the relationship between epilepsy, sleep and epileptogenesis; (d) the impact of epileptic activity during sleep on cognition; (e) the relationship between epilepsy and the circadian rhythm; (f) the history and features of sleep hypermotor epilepsy and its differential diagnosis; (g) the relationship between epilepsy and sleep disorders.

Predictors of hyperkinetic seizures

OBJECTIVE

To identify predisposing factors for hyperkinetic seizure occurrence in a representative cohort of surgically treated patients with drug-resistant focal epilepsy.

METHODS

We retrospectively recruited all seizure-free patients after epilepsy surgery with a postoperative follow-up ≥12 months. Patients were classified as presenting with hyperkinetic seizures if at least 2 episodes occurred during their disease history, based on clear-cut anamnestic description and/or video-EEG/stereo-EEG recordings. We performed univariable and multivariable logistic regression models to study the association between the occurrence of hyperkinetic seizures and some predictors.

RESULTS

From a pool of 1758 consecutive patients who underwent surgery from 1996 to 2017, we identified 974 seizure-free cases. Considering at least 1-year follow-up, 937 cases were included (511 males, 91 patients with hyperkinetic seizures). Variables significantly associated with an increased risk of hyperkinetic seizure occurrence were (1) presence of epilepsy with sleep-related seizures (SRE) (P < 0.001); (2) histological diagnosis of type II focal cortical dysplasia (FCD) (P < 0.001); (3) resection including the frontal lobe (P = 0.002) (4) duration of epilepsy at surgery (P < 0.001) and (5) high seizure frequency at surgery (weekly: P = 0.02 - daily: P = 0.05). A resection including the occipital lobe reduced the risk of hyperkinetic seizures (P = 0.05). About 63% of patients had hyperkinetic seizure onset before 12 years and it was rarely reported before 5 years of age.

SIGNIFICANCE

Our findings underlie the role of SRE, type II FCD and frontal epileptogenic zone as predictors of hyperkinetic seizure occurrence and highlight an age-dependent effect in favoring hyperkinetic manifestations.

Disorders of arousal and sleep-related hypermotor epilepsy - overview and challenges night is a battlefield of sleep and arousal promoting forces

Arousability and reactivity to sensory stimuli are essential features of sleep, discriminating it from coma and keeping the sleeper in contact with the environment. Arousals and oscillations during sleep serve the reversibility of sleep and carry an alarm function awakening the sleeper in danger. In this review, we will explore mechanisms and circuits involved in arousal intrusions within the sleep texture, focusing on the significance of these phenomena in two sleep-related conditions: NREM sleep parasomnias and sleep-related hypermotor epilepsy. Knowledges and gaps in the field are discussed.

Frontal lobe seizures: overview and update

Frontal lobe seizures (FLS) are debilitating for patients, highly diverse and often challenging for clinicians to evaluate. Frontal lobe epilepsy is the second most common localization for focal epilepsy, and if pharmacoresistant, can be amenable to resective surgery. Detailed study of frontal seizure semiology in conjunction with careful anatomical and electrophysiological correlation based on intracerebral recording with stereoelectroencephalography (SEEG) has allowed demonstration that ictal motor semiology reflects a hierarchical rostro-caudal axis of frontal lobe functional organization, thus helping with presurgical localization. Main semiological features allowing distinction between different frontal sublobar regions include motor signs and emotional signs. Frontal lobe seizure semiology also represents a valuable source of in vivo human behavioral data from a neuroscientific perspective. Advances in defining underlying etiologies of FLE are likely to be crucial for appropriate selection and exploration of potential surgical candidates, which could improve upon current surgical outcomes. Future research on investigating the genetic basis of epilepsies and relation to structural substrate (e.g. focal cortical dysplasia) and seizure organization and expression, could permit a "genotype-phenotype" approach that could be complementary to anatomical electroclinical correlations in better defining the spectrum of FLS. This could help with optimizing patient selection and prognostication with regards to therapeutic choices.

Clinical characteristics and postoperative seizure outcome in patients with mild malformation of cortical development and oligodendroglial hyperplasia

OBJECTIVE

We describe for the first time clinical characteristics in a series of 20 pre-surgically investigated patients with mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE) who were operated on in our epilepsy center. We aimed to better diagnose this entity and help surgical planning.

METHODS

Data on 20 patients with histologically confirmed MOGHE were retrospectively evaluated as to age at epilepsy onset and operation, seizure semiology, magnetic resonance imaging (MRI) localization, electroencephalography (EEG) patterns, extent of the operative resection, and postoperative seizure outcome.

RESULTS

Epilepsy began mainly in early childhood; however, symptoms did not manifest until adolescence or adulthood in 30% of patients. All patients had pathologic MRI findings. In 45% of patients the lesion was initially overlooked. Most commonly, the lesion was seen in the frontal lobe. Seizure semiology was characterized as follows: (1) epileptic spasms at epilepsy onset were common and (2) nocturnal hyperkinetic seizures during the course of the disease were rare. EEG always showed frequent interictal epileptic discharges. Two peculiar patterns were observed: (1) during sleep stage I-II, sub-continuous repetitive (0.5-1.5/s) unilateral plump spike/polyspike slow waves were seen and (2) during wakefulness, unilateral paroxysms of 2-2.5/s spike-wave complexes occurred. In total, 60% of patients were seizure-free 1 year postoperatively. Postoperative seizure outcome was positively correlated with the extent of resection, age at epilepsy onset, and age at operation. Postoperative long-term outcomes remained stable in patients undergoing larger operations.

SIGNIFICANCE

MRI, EEG, and semiology already contribute to the diagnosis of probable MOGHE preoperatively. Because postoperative seizure outcomes depend on the extent of the resection, prior knowledge of a probable MOGHE helps to plan the resection and balance the risks and benefits of such an intervention. In patients undergoing larger operations, epilepsy surgery achieved good postoperative results; the first long-term outcome data were stable in these patients.

Neural networks underlying hyperkinetic seizures: A quantitative PET and SEEG study

OBJECTIVE

Hyperkinetic seizures (HKS) are characterized by complex movements that commonly occur during seizures arising from diverse cortical structures. A common semiology network may exist and analyzing the anatomo-electrical mechanisms would facilitate presurgical evaluation. Here, quantitative positron emission tomography (PET) and stereoelectroencephalography (SEEG) analysis was used to explore the underlying mechanism of HKS.

METHODS

We retrospectively collected patients with epilepsy with HKS between 2014 and 2019. The interictal PET data of patients with epilepsy with HKS were compared with those of 25 healthy subjects using statistical parametric mapping to identify regions with significant hypometabolism. Then, regions of interest (ROI) for SEEG analysis were identified based on the results of PET analysis. Patients in which the ROIs were covered by intracerebral electrodes were selected for further analysis. Stereoelectroencephalography -clinical correlations with latency measurements were analyzed, and we also performed coherence analysis among ROIs both before and during HKS.

RESULTS

Based on the inclusion criteria, 27 patients were analyzed. In the PET analysis, significant hypometabolism was observed in the ipsilateral dorsoanterior insular lobe, bilateral mesial frontal lobes (supplementary motor area/middle cingulate cortex, SMA/MCC), and the bilateral heads of the caudate nuclei in patients with HKS compared with the control group (p < 0.001). We selected dorsoanterior insula and SMA/MCC as ROIs for SEEG analysis. Eight patients with 23 HKS events were selected for further analysis. There was a linear correlation between the ictal involvement of both the dorsoanterior insula and SMA/MCC with the onset of HKS. Stereoelectroencephalography analysis indicated alpha range activity seemed more often associated with dorsoanterior insula and SMA/MCC involvement during HKS.

CONCLUSIONS

The dorsoanterior insular lobe, mesial frontal lobes (SMA/MCC), and the bilateral heads of the caudate nuclei were probably involved in the generation of HKS. The SEEG analysis further indicated that the occurrence of HKS might be partly associated with synchronized rhythmical alpha activity between dorsoanterior insula and SMA/MCC.

A semiological marker of emotional insulo-cingulate network activation in epileptic human brain

There are limited reports on the "chapeau de gendarme" (CDG) sign, which is considered reliable evidence for the verification of frontal epilepsy. However, several recent reports of scattered cases of extra-frontal epilepsy suggest the complexity of the cortical networks underlying CDG generation. The present study aimed to investigate the anatomo-electro-clinical correlations and explore the cortical mechanisms of the generation of CDG via video-stereoelectroencephalography (SEEG). Patients with focal epilepsy who underwent SEEG and epilepsy surgery in our center from March 2017 to December 2019 were retrospectively reviewed. Ten patients with epilepsy with habitual seizures presenting with CDG were included. Most CDG signs were discerned visually into two chronological components referred to as the "prodromal component" and the "major component." The CDG signs occurred at 2.4-26.1 s after electrical onset and lasted for 2.2-16.6 s. The two sequential components were visually discerned in 64 included seizures of the six patients. The epileptogenic zones were diverse in distribution. Cluster analysis was performed based on the neurophysiological features of distinct cortical areas, and the agranulo-dysgranular insular and cingulate cortices were emphasized. Pearson correlation and linear regression showed a linear relationship between the latencies of CDG onset and the latencies of co-activation of agranulo-dysgranular cingulate and insular cortex in gamma bands. Our results suggest that (1) the CDG sign should be interpreted as a type of facial behavior with social-emotional features and considered a semiological marker of emotional insulo-cingulate cortex involvement in focal epilepsy, and (2) epileptic discharges arising directly from or propagating indirectly into this anterior limbic network have a high likelihood of evoking the CDG sign.

Seizure Freedom in Temporal Plus Epilepsy Surgery Following Stereo-Electroencephalography

BACKGROUND

"Temporal plus" epilepsy (TPE) is a term that is used when the epileptogenic zone (EZ) extends beyond the boundaries of the temporal lobe. Stereotactic electroencephalography (SEEG) has been essential to identify additional EZs in adjacent structures that might be part of the temporal lobe/limbic network.

OBJECTIVE

We present a small case series of temporal plus cases successfully identified by SEEG who were seizure-free after resective surgery.

METHODS

We conducted a retrospective analysis of 156 patients who underwent SEEG in 5 years. Six cases had TPE and underwent anterior temporal lobectomy (ATL) with additional extra-temporal resections.

RESULTS

Five cases had a focus on the right hemisphere and one on the left. Three cases were non-lesional and three were lesional. Mean follow-up time since surgery was 2.9 years (SD ± 1.8). Three patients had subdural electrodes investigation prior or in addition to SEEG. All patients underwent standard ATL and additional extra-temporal resections during the same procedure or at a later date. All patients were seizure-free at their last follow-up appointment (Engel Ia = 3; Engel Ib = 2; Engel Ic = 1). Pathology was nonspecific/gliosis for all six cases.

CONCLUSION

TPE might explain some of the failures in temporal lobe epilepsy surgery. We present a small case series of six patients in whom SEEG successfully identified this phenomenon and surgery proved effective.

Hyperkinetic Seizures with Ictal Fear as Localizing Ictal Signs in MRI-Negative Medial Frontal Lobe Epilepsy

PURPOSE

Hyperkinetic seizures are described as seizure onset in the frontal or temporal lobe. Additional localizing information is important for diagnostic workup and surgical therapy. We describe diagnostic workup and surgical outcomes in three patients with pharmacoresistant focal emotional seizures with hyperkinetic elements.

METHODS/RESULTS

High-resolution 3 Tesla (T) magnetic resonance imaging (MRI) did not reveal clear-cut lesions. Invasive video-electroencephalography (EEG) with depth electrodes along the cingulate sulcus (bilateral; patients 1 and 3), right; patient 2 provided congruent results for a circumscribed seizure onset zone within the medial frontal lobe (right: patients 1 and 2; left: patient 3). Topectomies were performed in all patients. Histopathology revealed a small focal cortical dysplasia in the three cases (focal cortical dysplasia [FCD] IIA: patient 1; FCD IIB: patients 2 and 3). All patients remained completely seizure-free since surgery (Engel 1A; follow-up: 9-28 months).

CONCLUSION

Ictal fear associated with hyperkinetic semiology points to a seizure-onset zone within the anteromedial frontal lobe (anterior cingulate gyrus). Ictal semiology is crucial for the placement of depth electrodes, especially in MRI-negative cases. These cases illustrate a clinical advantage to the new International League against Epilepsy (ILAE) seizure classification, emphasizing initial clinical symptoms.

Intricacies of GABAA Receptor Function: The Critical Role of the β3 Subunit in Norm and Pathology

Neuronal intracellular chloride ([Cl⁻]_i) is a key determinant in γ-aminobutyric acid type A (GABA)ergic signaling. γ-Aminobutyric acid type A receptors (GABA_ARs) mediate both inhibitory and excitatory neurotransmission, as the passive fluxes of Cl⁻ and HCO₃⁻ via pores can be reversed by changes in the transmembrane concentration gradient of Cl⁻. The cation–chloride co-transporters (CCCs) are the primary systems for maintaining [Cl⁻]_i homeostasis. However, despite extensive electrophysiological data obtained in vitro that are supported by a wide range of molecular biological studies on the expression patterns and properties of CCCs, the presence of ontogenetic changes in [Cl⁻]_i—along with the consequent shift in GABA reversal potential—remain a subject of debate. Recent studies showed that the β3 subunit possesses properties of the P-type ATPase that participates in the ATP-consuming movement of Cl⁻ via the receptor. Moreover, row studies have demonstrated that the β3 subunit is a key player in GABA_AR performance and in the appearance of serious neurological disorders. In this review, we discuss the properties and driving forces of CCCs and Cl⁻, HCO₃⁻ATPase in the maintenance of [Cl⁻]_i homeostasis after changes in upcoming GABA_AR function. Moreover, we discuss the contribution of the β3 subunit in the manifestation of epilepsy, autism, and other syndromes.

Sleep-Related Hypermotor Epilepsy: Etiology, Electro-Clinical Features, and Therapeutic Strategies

Sleep-related hypermotor epilepsy (SHE) is a group of clinical syndromes with heterogeneous etiologies. SHE is difficult to diagnose and treat in the early stages due to its diverse clinical manifestations and difficulties in differentiating from non-epileptic events, which seriously affect patients' quality of life and social behavior. The overall prognosis for SHE is unsatisfactory, but different etiologies affect patients' prognoses. Surgical treatment is an effective method for carefully selected patients with refractory SHE; nevertheless, preoperative assessment remains challenging because of the low sensitivity of noninvasive scalp electroencephalogram and imaging to detect abnormalities. However, through a careful analysis of semiology, the clinician can deduce the potential epileptogenic zone. This paper summarizes the research status of the background, etiology, electro-clinical features, diagnostic criteria, prognosis, and treatment of SHE to provide a more in-depth understanding of its pathophysiological mechanism, improve the accuracy in the diagnosis of this group of syndromes, and further explore more targeted therapy plans.

Abnormal blood oxygen level-dependent fluctuations and remote connectivity in sleep-related hypermotor epilepsy

OBJECTIVE

Sleep-related hypermotor epilepsy (SHE) is a form of the epileptic syndrome that involves stereotyped hypermotor seizures and presents as asymmetric tonic or dystonic posturing events. We aimed to investigate the brain activities of SHE patients using structural and functional magnetic resonance imaging (fMRI).

METHODS

A total of 41 patients with SHE and 41 age- and sex-matched healthy controls (HCs) were prospectively enrolled and assessed using fMRI. The two groups were compared in amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo), and potential correlations between these measures and clinical features were also examined. The involvement of functional network integration was explored by analyzing seed-based functional connectivity.

RESULTS

In SHE patients, ALFF in the right precentral gyrus was significantly higher than in HCs, and ReHo in the left postcentral and right precentral gyrus was higher. None of the brain regions had lower ALFF or ReHo compared to HCs. ReHo in the left postcentral gyrus and ALFF in the right precentral gyrus were both negatively correlated with epilepsy duration. Patients with SHE had higher functional connectivity mainly in the precuneus, postcentral gyrus, and supplementary motor area. However, none of the brain regions in SHE group presented lower functional connectivity than in HCs. SHE is associated with disrupted regional and interregional functional activities.

CONCLUSIONS

The patients showed abnormalities within the sensorimotor gyrus and supplementary motor area, suggesting spontaneous fluctuations correlated with remote functional brain network. These results at the whole-brain level argue for further investigation into connectivity disturbance in SHE.

Investigation of networks underlying hyperkinetic seizures utilizing ictal SPECT

Objective

To study neural networks involved in hyperkinetic seizures (HKS) using ictal SPECT.

Methods

We retrospectively identified 18 patients with HKS evaluated at the Cleveland Clinic between 2005 and 2015 with video-EEG monitoring and ictal SPECT. Semiology was confirmed by the consensus of 2 epileptologists' independent reviews and classified as type 1, 2, or 3 HKS. SPECT data were analyzed by 2 independent physicians using a z score of 1.5. Ictal hyperperfusion patterns for each group were analyzed visually and with SPM. Spatial normalization to Montreal Neurological Institute space for each patient’s data was performed, followed by flipping of data from patients with left-sided ictal onset to the right side. Finally, an average z score map for each group was calculated.

Results

Visual analysis and SPM identified different patterns of ictal hyperperfusion in the 3 subtypes of HKS. Type 1 seizures showed hyperperfusion in a more anteriorly located network involving the anterior insula, orbitofrontal cortex, cingulate, and anterior perisylvian region and rostral midbrain. Type 2 seizures were associated with hyperperfusion in a more caudally located network involving the orbitofrontal cortex, cingulate (middle and posterior), basal ganglia, thalami, and cerebellum. Type 3 seizures showed a mixed pattern of SPECT hyperperfusion involving the temporal pole and anterior perisylvian region.

Conclusions

Each of the 3 different semiologic subtypes of HKS is associated with distinct patterns of hyperperfusion, providing further insight into the neural networks involved. This knowledge may inform placement of invasive EEG electrodes in patients with HKS semiology undergoing presurgical evaluation.

Superior Frontal Sulcus Focal Cortical Dysplasia Type II: An MRI, PET, and Quantified SEEG Study

Purpose: The superior frontal sulcus (SFS), located in the prefrontal and premotor cortex, is considered as one of the common locations of focal cortical dysplasia (FCD). However, the characteristics of seizures arising from this area are incompletely known. The primary purpose of this study was to investigate the clinical features and the epileptic networks of seizures originating from the SFS.

Methods: We included seventeen patients with type II FCD within the SFS. SFS was identified both visually and automatically. Semiological features were evaluated and grouped. Interictal 18FDG-PET imaging in all patients was compared to controls using statistical parametric mapping (SPM-PET). In those subjects with stereoelectroencephalography (SEEG), two different quantitative intracranial electroencephalography analyses were applied. Finally, the locations of the SFS-related hypometabolic regions and epileptogenic zones (EZs) were transformed into standard space for group analysis.

Results: We identified two semiological groups. Group 1 (9/17) showed elementary motor signs (head version and tonic posturing), while group 2 (8/17) exhibited complex motor behavior (fear, hypermotor, and ictal pouting). Based on SPM-PET, an SFS-supplementary motor area (SMA) epileptic propagation network was found in group 1, and an SFS-middle cingulate cortex (MCC)-pregenual anterior cingulate cortex (pACC) propagation network was discovered in group 2. Intracranial EEG analysis suggested similar affected structures with high epileptogenicity. The SFS-related hypometabolic regions and EZs in these groups showed a posterior-anterior spatial relationship.

Conclusions: Even though originating from the spatially restricted cortex, SFS seizures can be divided into two groups based on semiological features. The SFS-SMA and SFS-MCC-pACC epileptic propagation networks may play pivotal roles in the generation of different semiologies. The posterior-anterior spatial relationship of both hypometabolic regions and EZs provides potentially useful information for distinguishing different types of SFS seizures and surgical evaluation.

Insights into sleep-related hyper-motor epilepsy: an Egyptian case series

Objective: Sleep-related hypermotor epilepsy (SHE) is a sleep-related focal epilepsy which is often misdiagnosed. Despite active pharmacological therapy in the management of this disorder, satisfactory seizure control still cannot be achieved. Therefore, the aim of the present study was to identify this disorder among people who were seeking medical advice at Cairo University Epilepsy Unit (CUEU), characterizing its clinical, electroencephalographic and imaging features besides identifying possible indicators of inadequate seizure control on drug-therapy. Patients and methods: This study was carried out on 26 patients with SHE who were subjected to detailed history taking and examination in addition to home video recording, video electroencephalographic (EEG) monitoring and brain imaging. Ictal semiology and EEGs were reviewed and analyzed by experienced neurologists. Results: SHE is an uncommon sleep-related focal epilepsy. In our series, median age of the patients was 18.5 years. It is characterized by being sporadic, with often frontal lobe seizure onset (14/26, 53.8%) and with occasional occurrence in wakefulness. Adolescence age at disease onset (11 years, 6-15), duration less than 1 min, clustering, lack of auras and often uninformative brain imaging (22/25, 88%) are all documented features. Moreover, it has a relatively poor outcome on pharmacological therapy (16/26, 61.5%). Longer disease duration (>4.5 years) was a significant feature of the patients exhibiting inadequate seizure control. Conclusions: Our data show relatively poor prognosis of SHE on medical therapy. Its outcome is significantly related to disease duration at the time of diagnosis. Abbreviation: SHE = Sleep related hypermotor epilepsy.

Localization value of ictal turning prone

PURPOSE

Ictal semiology complements ictal EEG in identifying the likely epileptogenic zone. Ictal turning prone (ITP) with body turning of 90 ° or more can be seen with frontal lobe epilepsies. The aim of our study was to evaluate the localizing value of ITP in a general population of patients undergoing long term video-EEG monitoring.

METHODS

We reviewed our epilepsy monitoring unit database for adult patients with recorded habitual seizures with ITP. All 16 patients identified had continuous video-EEG monitoring using standard scalp electrodes; eight patients also had intracranial EEG monitoring. We only included focal seizures without evolution to bilateral tonic-clonic activity.

RESULTS

We identified 16 patients with ITP, mean age of 32.5 years (range 18-50). ITP was consistently seen in at least one focal impaired awareness seizure of all patients. Ictal onset zone on scalp EEG was left temporal in five, right temporal in three, left frontal convexity in two, right frontal convexity in two, probable right medial frontal in three and probable left medial frontal in one patient. Direction of ITP was uni-directional in 12 patients while 4 patients had ITP in opposite direction in different seizures. Nine patients underwent epilepsy surgery; five patients had Engel class I outcome and four patients had Engel class III outcome.

CONCLUSIONS

Ictal turning prone does not have a consistent single localizing or lateralizing value and can be seen with various epileptogenic zones including medial frontal, lateral frontal or temporal. ITP direction can vary even with a single epileptogenic zone.

Distinctive epileptogenic networks for parietal operculum seizures

OBJECTIVE

The present study investigated the electroclinical features and epileptogenic networks of parietal operculum seizures (POS) by using stereoelectroencephalography (SEEG) intracerebral recordings.

METHODS

Comprehensive presurgical evaluation data of seven patients with drug-resistant epilepsy with POS were analyzed retrospectively. Stereoelectroencephalography-recorded seizures were processed visually and quantitatively by using epileptogenicity mapping (EM), which has been proposed to ergonomically quantify the epileptogenicity of brain structures with a neuroimaging approach.

RESULTS

Six patients reported initial somatosensory or viscerosensitive symptoms. Ictal clinical signs comprised frequently nocturnal hypermotor seizures and contralateral focal motor seizures, including tonic, tonic-clonic, or dystonic seizures of the face and limbs. Interictal and ictal scalp EEG provided information regarding lateralization in the majority of patients, but the discharges were widely distributed over perisylvian or "rolandic-like" regions and the vertex. Furthermore, two subgroups of epileptogenic network organization were identified within POS by SEEG, visually and quantitatively, using an EM approach: group 1 (mesial frontal/cingulate networks) was observed in three patients who mainly exhibited hypermotor seizures; group 2 (perisylvian networks) was observed in four patients who mainly exhibited contralateral focal motor seizures.

CONCLUSION

This study indicated that POS could be characterized by initial specific somatosensory sensations, followed by either frequently nocturnal hypermotor seizures or contralateral focal motor seizures. The distinctive seizure semiology depended on the organization of two primary epileptogenic networks. This article is part of the Special Issue "Individualized Epilepsy Management: Medicines, Surgery and Beyond.

Electroclinical characteristics of seizures arising from the precuneus based on stereoelectroencephalography (SEEG)

Background

Seizures arising from the precuneus are rare, and few studies have aimed at characterizing the clinical presentation of such seizures within the anatomic context of the frontoparietal circuits. We aimed to characterize the electrophysiological properties and clinical features of seizures arising from the precuneus based on data from stereoelectroencephalography (SEEG).

Methods

The present retrospective study included 10 patients with medically intractable epilepsy, all of whom were diagnosed with precuneal epilepsy via stereoelectroencephalography (SEEG) at Yuquan Hospital and Xuan Wu Hospital between 2014 and 2016. Clinical semiology, scalp electroencephalography (EEG) findings, magnetic resonance images (MRI), and positron emission tomography (PET) images were analyzed during phase I preoperative evaluations. Following electrode implantation, the semiological sequence, ictal SEEG evolution, and anatomy of the relevant brain structures were analyzed for each seizure.

Results

Seven of ten patients reported auras, including body image disturbance (2/7), vestibular responses (2/7), somatosensory auras (1/7), visual auras (1/7), and non-specific auras (1/7). Primary motor manifestations included bilateral asymmetric tonic seizures (BATS) (7/10) and hypermotor seizures (HMS) (3/10). In one patient, epileptiform discharge on interictal EEG occurred ipsilateral to the side of the epileptogenic zone (EZ). Discharge was non-lateralized in the remaining nine patients. In six patients, interictal EEG signals were primarily localized in the temporal–parietal–occipital area. In two patients, ictal onset occurred ipsilateral to the EZ, which was mainly located in the temporal–parietal–occipital area. Two patterns of seizure spread were observed. The first pattern was characterized by BATS activity with ictal spread to the supplementary motor area (SMA), paracentral lobule (PCL), precentral gyrus (PrCG), or postcentral gyrus (PoCG). The second pattern was characterized by HMS activity with ictal spread to middle cingulate cortex (MCC) and posterior cingulate cortex (PCC).

Conclusion

Aura type (e.g., body image disturbance and vestibular response), BATS, and HMS are the main indicators of precuneal epilepsy. Scalp EEG is of little use when attempting to localize precuneal seizures. Our findings indicate that the clinical characteristics of precuneal epilepsy vary among patients, and that the final electro–clinical phenotype depends on the pattern of seizure spread.

The Anatomo-Electrical Network Underlying Hypermotor Seizures

Purpose

Hypermotor seizures (HMS) can be triggered by different epileptogenic foci and thus common symptomatic networks generating HMS may exist among these patients. The goal of the present study was to investigate the specialized networks underlying HMS by analyzing interictal ¹⁸FDG-PET imaging and ictal stereo-electroencephalography (SEEG) recordings.

Methods

Fourteen patients with HMS were retrospectively analyzed. HMS were classified into HMS1 and HMS2 according to the speed and intensity of the motor seizure behavior. Then, the interictal PET data of patients was compared with those of 18 healthy controls using statistical parametric mapping to identify regions with significant hypometabolism. Ictal SEEG recordings were reviewed to identify the spreading areas at the beginning of HMS occurrence.

Results

Compared to controls, patients with HMS presented significant hypometabolism in the bilateral anterosuperior insular lobes, mesial premotor cortex (MPMC), middle cingulate cortex (MCC), as well as in the bilateral caudate nuclei. When comparing patients in the two HMS subgroups with controls, more extensive hypometabolic areas were seen in HMS1 patients than in HMS2 patients, including the orbitofrontal cortex (OFC), the temporal pole, and the anterior cingulate cortex (ACC). OFC and ventromedial prefrontal cortex was also found significantly hypometabolic in patients with HMS1 when compared with HMS2 directly. SEEG recordings further suggested that insula, MCC, and MPMC were commonly recruited at the beginning of HMS.

Conclusion

We have identified a specialized interictal hypometabolic pattern in patients with HMS. A network involving the anterosuperior insula, mesiofrontal cortex (MCC-MPMC), and caudate nucleus may contribute to the generation of HMS. ACC, OFC, and temporal pole are possibly associated with the affective components of HMS. Our findings provide further insight into understanding the network basis of HMS semiology.

Brain functional connectivity in sleep-related hypermotor epilepsy

Objectives

To evaluate functional connectivity (FC) in patients with sleep-related hypermotor epilepsy (SHE) compared to healthy controls.

Methods

Resting state fMRI was performed in 13 patients with a clinical diagnosis of SHE (age = 38.3 ± 11.8 years, 6 M) and 13 matched healthy controls (age = 38.5 ± 10.8 years, 6 M).

Data were first analysed using probabilistic independent component analysis (ICA), then a graph theoretical approach was applied to assess topological and organizational properties at the whole brain level. We evaluated node degree (ND), betweenness centrality (BC), clustering coefficient (CC), local efficiency (LE) and global efficiency (GE). The differences between the two groups were evaluated non-parametrically.

Results

At the group level, we distinguished 16 RSNs (Resting State Networks). Patients showed a significantly higher FC in sensorimotor and thalamic regions (p < 0.05 corrected). Compared to controls, SHE patients showed no significant differences in network global efficiency, while ND and BC were higher in regions of the limbic system and lower in the occipital cortex, while CC and LE were higher in regions of basal ganglia and lower in limbic areas (p < 0.05 uncorrected).

Discussion and conclusions

The higher FC of the sensorimotor cortex and thalamus might be in agreement with the hypothesis of a peculiar excitability of the motor cortex during thalamic K-complexes. This sensorimotor-thalamic hyperconnection might be regarded as a consequence of an alteration of the arousal regulatory system in SHE. An altered topology has been found in structures like basal ganglia and limbic system, hypothesized to be involved in the pathophysiology of the disease as suggested by the dystonic-dyskinetic features and primitive behaviours observed during the seizures.

•

Resting state functional connectivity was studied for the first time in SHE.

•

SHE patients showed higher connectivity in thalamic and motor regions.

•

Motor cortex might show a higher excitability in response to thalamic projections.

•

Brain network topology was altered mainly in basal ganglia and limbic system.

Proton MR Spectroscopy in Patients With Sleep-Related Hypermotor Epilepsy (SHE): Evidence of Altered Cingulate Cortex Metabolism

Study Objectives

To identify structural and/or metabolic alterations in patients with sleep-related hypermotor epilepsy (SHE) using magnetic resonance imaging (MRI) and proton MR spectroscopy (1H-MRS).

Methods

Nineteen SHE patients (seven males; 34.7 ± 9.7 years, mean age ± standard deviation) and 17 matched healthy volunteers (seven males; 34.0 ± 8.9 years) were included in the study. In all patients, the diagnosis of SHE was confirmed by video-polysomnographic recording of seizures. Semiology, seizure frequency, and therapy were assessed for all patients. For each recruited participant, structural MRI and 1H-MRS sequences were acquired. 1H-MRS was performed on two regions of interest: the medial thalamus and the anterior cingulate gyrus.

Results

At examination, five patients were seizure free. In the remainder, seizure frequency ranged from yearly to multiple episodes per night. Brain MRI was normal in all patients but one. The ratio of N-acetyl-aspartate/Creatine (NAA/Cr) was significantly reduced in the anterior cingulate cortex in patients compared to controls (p < .05). Thalamic NAA/Cr showed no differences between patients and controls. Regression analysis showed that NAA/Cr in the anterior cingulate gyrus correlated with seizure frequency (p < .05), being lower in patients with higher seizure frequency.

Conclusions

Given the absence of structural MR changes, our 1H-MRS data point to a functional NAA reduction in the cingulate cortex of SHE patients, more severe in those patients with higher seizure frequency and thus supporting the involvement of the anterior mesial structures in the pathophysiology of SHE.

Mesial Extratemporal Lobe Epilepsy: Clinical Features and Surgical Strategies

BACKGROUND: Extratemporal lobe epilepsy surgery remains a diagnostic and therapeutic challenge. Scalp electroencephalography (EEG) correlates, clinical semiology, and imaging findings are often ambiguous or difficult to interpret, necessitating the need for invasive recordings. This is particularly true for those extratemporal lobe epilepsy cases in which seizures develop from the midline.

OBJECTIVE: The aim of this study was to examine the clinical features and surgical strategies in mesial extratemporal lobe epilepsy.

METHODS: A retrospective study reviewing clinical and surgical characteristics was conducted in 30 patients who underwent epilepsy surgery in mesial extratemporal areas at our institution between 1991 and 2011.

RESULTS: Although the location of the epileptogenic zone was associated with specific seizure types, semiology proved to be heterogeneous. Although scalp EEG was of good lateralizing value, it was poor for localizing the epileptogenic zone, necessitating a frequent need for invasive electroencephalographic recordings.

CONCLUSION: Surgical resections in mesial extratemporal regions were found to be safe and resulted in satisfactory seizure outcomes.

Temporal lobe origin is common in patients who have undergone epilepsy surgery for hypermotor seizures

RATIONALE

Hypermotor seizures are most often reported from the frontal lobe but may also have temporal, parietal, or insular origin. We noted a higher proportion of patients with temporal lobe epilepsy in our surgical cohort who had hypermotor seizures. We evaluated the anatomic localization and surgical outcome in patient with refractory hypermotor seizures who had epilepsy surgery in our center.

METHODS

We identified twenty three patients with refractory hypermotor seizures from our epilepsy surgery database. We analyzed demographics, presurgical evaluation including semiology, MRI, PET scan, interictal/ictal scalp video-EEG, intracranial recording, and surgical outcomes. We evaluated preoperative variables as predictors of outcome.

RESULTS

Most patients (65%) had normal brain MRI. Intracranial EEG was required in 20 patients (86.9%). Based on the presurgical evaluation, the resection was anterior temporal in fourteen patients, orbitofrontal in four patients, cingulate in four patients, and temporoparietal in one patient. The median duration of follow-up after surgery was 76.4months. Fourteen patients (60%) had been seizure free at the last follow up while 3 patients had rare disabling seizures.

CONCLUSIONS

Hypermotor seizures often originated from the temporal lobe in this series of patients who had epilepsy surgery. This large proportion of temporal lobe epilepsy may be the result of a selection bias, due to easier localization and expected better outcome in temporal lobe epilepsy. With extensive presurgical evaluation, including intracranial EEG when needed, seizure freedom can be expected in the majority of patients.

Coprolalia as a manifestation of epileptic seizures

OBJECTIVE

The aim of this study was to investigate the lateralizing and localizing value of ictal coprolalia and brain areas involved in its production.

METHODS

A retrospective search for patients manifesting ictal coprolalia was conducted in our EMU database. Continuous video-EEG recordings were reviewed, and EEG activity before and during coprolalia was analyzed using independent component analysis (ICA) technique and was compared to the seizures without coprolalia among the same patients.

RESULTS

Nine patients were evaluated (five women), eight with intracranial video-EEG recordings (icVEEG). Four had frontal or temporal lesions, and five had normal MRIs. Six patients showed impairment in the language functions and five in the frontal executive tasks. Two hundred six seizures were reviewed (60.7% from icVEEG). Ictal coprolalia occurred in 46.6% of them, always associated with limbic auras or automatisms. They arose from the nondominant hemisphere in five patients, dominant hemisphere in three, and independently from the right and left hippocampus-parahippocampus in one. Electroencephalographic activity always involved orbitofrontal and/or mesial temporal regions of the nondominant hemisphere when coprolalia occurred. Independent component analysis of 31 seizures in seven patients showed a higher number of independent components in the nondominant hippocampus-parahippocampus before and during coprolalia and in the dominant lateral temporal region in those seizures without coprolalia (p=0.009). Five patients underwent surgery, and all five had an ILAE class 1 outcome.

SIGNIFICANCE

Ictal coprolalia occurs in both males and females with temporal or orbitofrontal epilepsy and has a limited lateralizing value to the nondominant hemisphere but can be triggered by seizures from either hemisphere. It involves activation of the paralimbic temporal-orbitofrontal network.

Definition and diagnostic criteria of sleep-related hypermotor epilepsy

The syndrome known as nocturnal frontal lobe epilepsy is recognized worldwide and has been studied in a wide range of clinical and scientific settings (epilepsy, sleep medicine, neurosurgery, pediatric neurology, epidemiology, genetics). Though uncommon, it is of considerable interest to practicing neurologists because of complexity in differential diagnosis from more common, benign sleep disorders such as parasomnias, or other disorders like psychogenic nonepileptic seizures. Moreover, misdiagnosis can have substantial adverse consequences on patients' lives. At present, there is no consensus definition of this disorder and disagreement persists about its core electroclinical features and the spectrum of etiologies involved. To improve the definition of the disorder and establish diagnostic criteria with levels of certainty, a consensus conference using formal recommended methodology was held in Bologna in September 2014. It was recommended that the name be changed to sleep-related hypermotor epilepsy (SHE), reflecting evidence that the attacks are associated with sleep rather than time of day, the seizures may arise from extrafrontal sites, and the motor aspects of the seizures are characteristic. The etiology may be genetic or due to structural pathology, but in most cases remains unknown. Diagnostic criteria were developed with 3 levels of certainty: witnessed (possible) SHE, video-documented (clinical) SHE, and video-EEG-documented (confirmed) SHE. The main research gaps involve epidemiology, pathophysiology, treatment, and prognosis.

Semiology of hypermotor (hyperkinetic) seizures

BACKGROUND

Hypermotor seizures (HMSs) consist of complex movements involving proximal segments of the limbs and trunk that appear violent and inappropriate for the situation.

METHODS

We analyzed hypermotor seizure videos in seizure-free patients (Engel class I) following resective epilepsy surgery. After completion of video analysis, we reviewed EEG and neuroimaging data.

RESULTS

Search of our epilepsy surgery database yielded 116 patients classified as having hypermotor seizures between 1996 and 2013. From this subset, 17/31 (55%) patients had been seizure-free for >6months (mean follow-up: 3.3years). Mean seizure duration was 35s (range: 6-91s), of which the HM phase lasted a mean of 22s (range: 3-53s). In 16 patients (95%), hypermotor activity was seen at or within 10s of clinical seizure onset. Type I semiology occurred in 6 patients, type II semiology in 10 patients, and 1 patient exhibited features of both. Type I and type II semiologies were noted in patients who had frontal lobe as well as extrafrontal resections. Nonversive head and body turning occurred in 10 patients (ranging from 90° to 270°) which was ipsilateral to the side of resection in all patients and seen both in frontal and extrafrontal resections. Six out of eleven patients with abnormal MRI and 4/6 patients with nonlesional MRI underwent invasive EEG evaluation. Eight patients (47%) had frontal lobe resection, 4/17 (23%) patients had temporal lobe resection, and one patient each had parietal lobe, insular, temporoparietooccipital, or motor sparing resection; 1 patient had functional hemispherectomy.

CONCLUSION

Hypermotor semiology typically occurs at or within 10s after seizure onset. Ipsilateral head/body turning appears to be of lateralizing value whereas asymmetry of limb movement was not lateralizing. Hypermotor semiology is most often seen in frontal lobe epilepsy but may occur in seizures arising from other locations.

Prevalence of nocturnal frontal lobe epilepsy in the adult population of Bologna and Modena, Emilia-Romagna region, Italy

STUDY OBJECTIVES

To estimate the prevalence of nocturnal frontal lobe epilepsy (NFLE) in the adults of two areas of the Emilia-Romagna region (northeast Italy) and to describe the clinical features from a population-based perspective.

DESIGN

Population-based retrospective cohort study including adults with NFLE.

SETTING

Two areas of the Emilia-Romagna region: the city of Bologna (330,901 adult residents) and five districts of the province of Modena (424,007). Prevalence day: December 31, 2010.

PARTICIPANTS

Patients with NFLE collected from multiple databases of neurologic hub centers of the districts involved. Diagnostic criteria: clinical history of sleep related bizarre motor attacks and videopolysomnographic recording confirming the typical features of NFLE. Inclusion criteria for prevalence calculation: residence in one of the two geographic areas on the prevalence day and an "active" or "in remission with treatment" form of NFLE.

MEASUREMENTS AND RESULTS

Six subjects from Bologna and eight from Modena were included. Crude prevalence (per 100,000 residents) was 1.8 (95% confidence interval 0.7-4.0) in Bologna and 1.9 (0.8-3.7) in Modena. Similarly, the main clinical features were consistent: onset during adolescence (median age 11-13 y), mainly hyperkinetic seizures, nonlesional form in more than two-thirds of cases, an active form of epilepsy in more than two-thirds of cases. A family history of epilepsy was reported only for two patients.

CONCLUSIONS

This epidemiologic study establishes that NFLE is a rare epileptic condition, fulfilling the definition for rare disease. Because of methodological limitations of our case ascertainment, the estimates we disclose must be considered the minimum prevalence.