Nocturnal Frontal Lobe Epilepsy Seizures Research Articles

Application of self-organizing map to identify nocturnal epileptic seizures

An approach to find the best patient-specific seizure detection system for nocturnal frontal lobe epilepsy (NFLE) is proposed. Data of several patients affected by NFLE, extracted from the European Epilepsy Database, have been used for this study. As every patient possesses different physiological characteristics, several simulations were performed in order to find the best features to be extracted from the best number of electroencephalogram (EEG) channels and to be inputted to two-dimensional self-organizing maps (SOM). The proposed method allows the definition of maps capable of presenting meaningful information on the actual brain state, revealing the mapping potential of clustering the data coming from seizure and non-seizure patterns; moreover, it also suggests to use SOM for early seizure detection. In fact, the temporal sequence of the patterns in an EEG recording can be projected on the SOM, obtaining a trajectory that describes the dynamics of the brain state as captured by the EEG. The analysis of this trajectory allows one to detect the seizure event, highlighting the possibility to promote therapies aimed at rapid and targeted disarming the seizures. A further contribution of the paper is to propose a methodology to be followed to customize the prediction model to a new patient. The performances of the proposed approach, in terms of sensitivity and specificity, have been compared with those of other well-established detection models proving it is a good alternative to early and accurately detect nocturnal frontal lobe epilepsy seizures.

Nocturnal Frontal Lobe Epilepsy and the Acetylcholine Receptor

Nocturnal frontal lobe epilepsy (NFLE) is an idiopathic partial epilepsy characterized by a wide spectrum of stereotyped motor manifestations, mostly occurring during non rapid eye movements sleep. NFLE is underdiagnosed since semiological similarities make it difficult to distinguish NFLE from parasomnias. In 1994, authors reported families with NFLE inherited as an autosomal dominant trait and they introduced the term of autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). A family history of possible NFLE is found in about 25% of cases. The genetic bases of the disease have been detected in a minority of cases. Mutations causing a gain of function of the neuronal nicotinic acetylcholine receptors were reported in 3 different subunits. This review discusses the clinical aspects of NFLE and the diagnostic procedures. Furthermore, the genetic aspects are outlined. The main differentiating features characterizing NFLE are: (a) several attacks per night at any time during the night; (b) brief duration of the attacks; (c) stereotyped motor pattern. Nocturnal video-polysomnography is crucial for the diagnosis. Neurological examination in NFLE/ADNFLE is normal. About 30% of NFLE cases are resistant to antiepileptic drugs. Concerning the genetics, putative susceptibility nucleotide variations affecting the promoter of the CRH gene and altering the corticotrophin-releasing hormone levels have been reported in some NFLE patients. Distinguishing NFLE seizures from paroxysmal nonepileptic sleep disorders is often difficult and sometimes impossible on clinical grounds alone. Nocturnal video-polysomnography is mandatory. Further genetic studies could help the diagnosis and treatment in NFLE patients.

Physiologic autonomic arousal heralds motor manifestations of seizures in nocturnal frontal lobe epilepsy: Implications for pathophysiology

This study describes changes in heart rate (HR) and HR variability (HRV) related to clinical onset of seizures in nocturnal frontal lobe epilepsy (NFLE) in order to determine whether signs of autonomic activation precede onset of seizure motor manifestations, which was selected as seizure onset (SO). Further, to clarify the nature (epileptic or physiologic) of the changes in autonomic cardiac control presumed to precede SO, time-dependent variations in HR and HRV related to physiological cortical arousals associated with motor activity (phases of transitory activation, PAT) were also investigated. HR and HRV spectral power, quantified by means of wavelet transform, were analyzed in relation to the onset of motor manifestations in 45 NFLE seizures and 45 PAT derived from whole night video-polysomnographic recordings of ten patients and of ten control subjects, respectively. Analysis of HRV showed a shift of sympathetic/parasympathetic cardiac control toward a sympathetic predominance in the 10s immediately preceding SO, while changes in HR were evident only one second before SO. This sympathetic activation was not associated with a sleep-wake transition or changes in respiratory activity, both of which occurred concurrently with SO. Similar changes in HR and HRV were observed in the 10s before the motor and electroencephalographic onset of PAT. Our study demonstrates that a similar autonomic activation precedes the motor manifestations of NFLE seizures and physiological arousal. This autonomic activation could represent part of the arousal response, which could be implicated in the occurrence of both seizure and arousal motor manifestations.

Parasomnias and nocturnal frontal lobe epilepsy (NFLE): Lights and shadows – Controversial points in the differential diagnosis

Nocturnal frontal lobe epilepsy (NFLE) is characterized by seizures with complex, often bizarre, violent behaviour arising only or mainly during sleep. These unusual seizures and their occurrence during sleep are often accompanied by normal EEG tracings and neuroradiological findings, making it difficult to distinguish NFLE seizures from other non-epileptic nocturnal paroxysmal events, namely parasomnias. NFLE was described for the first time in 1981, but, as its epileptic origin was controversial, the condition was called nocturnal paroxysmal dystonia. Even though many aspects of parasomnias and NFLE have been clarified in the last two decades, the problem of differential diagnosis remains a challenge for clinicians. This paper discusses some controversial points still under debate. The difficulties in distinguishing nocturnal epileptic seizures from parasomnias reflect just one aspect of the intriguing issue of the pathophysiological relationships between all types of paroxysmal motor behaviours during sleep.

NREM Arousal Parasomnias and Their Distinction from Nocturnal Frontal Lobe Epilepsy: A Video EEG Analysis

To describe the semiological features of NREM arousal parasomnias in detail and identify features that can be used to reliably distinguish parasomnias from nocturnal frontal lobe epilepsy (NFLE). Systematic semiologial evaluation of parasomnias and NFLE seizures recorded on video-EEG monitoring. 120 events (57 parasomnias, 63 NFLE seizures) from 44 subjects (14 males). Interventions. The presence or absence of 68 elemental clinical features was determined in parasomnias and NFLE seizures. Qualitative analysis of behavior patterns and ictal EEG was undertaken. Statistical analysis was undertaken using established techniques. Elemental clinical features strongly favoring parasomnias included: interactive behavior, failure to wake after event, and indistinct offset (all P < 0.001). Cluster analysis confirmed differences in both the frequency and combination of elemental features in parasomnias and NFLE. A diagnostic decision tree generated from these data correctly classified 94% of events. While sleep stage at onset was discriminatory (82% of seizures occurred during stage 1 or 2 sleep, with 100% of parasomnias occurring from stage 3 or 4 sleep), ictal EEG features were less useful. Video analysis of parasomnias identified three principal behavioral patterns: arousal behavior (92% of events); non-agitated motor behavior (72%); distressed emotional behavior (51%). Our results broadly support the concept of confusion arousals, somnambulism and night terrors as prototypical behavior patterns of NREM parasomnias, but as a hierarchical continuum rather than distinct entities. Our observations provide an evidence base to assist in the clinical diagnosis of NREM parasomnias, and their distinction from NFLE seizures, on semiological grounds.

Can Homemade Video Recording Become More Than a Screening Tool?

Can Homemade Video Recording Become More Than a Screening Tool?

Nocturnal epileptic seizures versus the arousal parasomnias

We review here the clinical features of Nocturnal Frontal Lobe Epilepsy (NFLE) and the arousal parasomnias, to define possible differential diagnostic criteria and their inter-observer reliability, and to determine whether both conditions share a common disturbance of arousal mechanisms. Polysomnographic recordings defined several types of seizures in NFLE: Paroxysmal Arousals (PA), Nocturnal Paroxysmal Dystonia (NPD), Epileptic Nocturnal Wanderings (ENW). There are however several difficulties with the diagnosis of NFLE, not the least being that EEG discharges during the seizures are not universally found. These diagnostic difficulties are highlighted, as well as the fact that studies of the inter-observer reliability of the video polysomnographic features of NFLE were found unsatisfactory, especially for the PA. When NFLE patients and their relatives were matched to control subjects and analysed in regard to personal and family history for the parasomnias, the arousal parasomnias were reported significantly higher by patients with NFLE and their relatives. This higher recurrence of a personal and family history for the parasomnias in NFLE patients suggests that the two conditions share a common underlying mechanism. Based on evidence from Autosomal Dominant NFLE, a genetic disorder with mutations in nicotinic acetylcholine receptors(nAchR), we hypothesise that arousal parasomnias and NFLE both, have abnormal arousal mechanisms in the dorsal cholinergic arousal branch triggering peculiar motor patterns in the medial frontal lobe regions.

Movement disorders in sleep: Guidelines for differentiating epileptic from non-epileptic motor phenomena arising from sleep

Seizures, namely in certain epileptic conditions, may be precipitated by sleep. Nocturnal frontal lobe epilepsy seizures, characterized by bizarre motor behaviour and autonomic activation, appear almost exclusively during sleep. The differential diagnosis between this condition and sleep-related non-epileptic paroxysmal motor phenomena, in particular the parasomnias, is arduous. Moreover, accepted criteria for the diagnosis of nocturnal frontal lobe seizures are lacking and even ictal scalp EEG recording could fail to disclose paroxysmal abnormalities. The clinical and polygraphic features of the different types of seizures in nocturnal frontal lobe epilepsy and of the more common non-epileptic paroxysmal events during sleep are described. The main differentiating features characterizing nocturnal frontal seizures are: onset at any age, several attacks per night at any time during the night, brief duration (s) with stereotyped motor pattern. As video-polysomnographic recordings of the attack, the gold-standard for diagnosis, are expensive and not readily available everywhere, home-made video recordings may be helpful. Further investigations on pathophysiology, genetics and epidemiology are needed to clarify the relationship between epileptic and non-epileptic sleep related paroxysmal phenomena.

Nocturnal frontal lobe epilepsy. A clinical and polygraphic overview of 100 consecutive cases.

Nocturnal frontal lobe epilepsy (NFLE) has been delineated as a distinct syndrome in the heterogeneous group of paroxysmal sleep-related disturbances. The variable duration and intensity of the seizures distinguish three non-rapid eye movement-related subtypes: paroxysmal arousals, characterized by brief and sudden recurrent motor paroxysmal behaviour; nocturnal paroxysmal dystonia, motor attacks with complex dystonic-dyskinetic features; and episodic nocturnal wanderings, stereotyped, agitated somnambulism. We review the clinical and polysomnographic data related to 100 consecutive cases of NFLE in order to define the clinical and neurophysiological characteristics of the different seizure types that constitute NFLE. NFLE seizures predominate in males (7:3). Age at onset of the nocturnal seizures varies, but centres during infancy and adolescence. A familial recurrence of the epileptic attacks is found in 25% of the cases, while 39% of the patients present a family history of nocturnal paroxysmal episodes that fit the diagnostic criteria for parasomnias. A minority of cases (13%) have personal antecedents (such as birth anoxia, febrile convulsions) or brain CT or MRI abnormalities (14%). In many patients, ictal (44%) and interictal (51%) EEGs are uninformative. Marked autonomic activation is a common finding during the seizures. NFLE does not show a tendency to spontaneous remission. Carbamazepine completely abolishes the seizures in approximately 20% of the cases and gives remarkable relief (reduction of the seizures by at least 50%) in another 48%. VideoEEG recordings confirm that NFLE comprises a spectrum of distinct phenomena, different in intensity but representing a continuum of the same epileptic condition. We believe that the detailed clinical and videoEEG characterization of patients with NFLE represents the first step towards a better understanding of the pathogenic mechanisms and different clinical outcomes of the various seizure types that constitute the syndrome.