Dipole reversal: an ictal feature of benign partial epilepsy with centrotemporal spikes

Seizures in self-limited epilepsy with centrotemporal spikes: video-EEG documentation

PURPOSE

Self-limited epilepsy with centrotemporal spikes, formerly called benign epilepsy with centrotemporal spikes, or rolandic epilepsy, is an age-related and well-defined epileptic syndrome. Since seizures associated with rolandic spikes are infrequent and usually occur during sleep, and repetitive or prolonged EEG recording for diagnostic purposes is not necessary for diagnosis, reports of ictal video-electroencephalographic seizures in this syndrome are rare. We aimed to show ictal video-EEG of typical rolandic seizures.

METHODS

We report the ictal video-EEG recordings of two children with rolandic epilepsy who presented typical rolandic seizures during routine recording.

RESULTS

Case 1: A 9-year-old boy, with normal development, had his first seizure at 8 years old, characterized by paresthesia in his left face, blocking of speech, and drooling. Carbamazepine was started with seizure control. Case 2: A 10-year-old boy, with normal development, started with focal seizures during sleep, characterized by eye and perioral deviation, and speech arrest at age of 7. He started using oxcarbazepine. Both patients underwent routine electroencephalography for electroclinical diagnosis and presented a seizure.

CONCLUSION

Although self-limited epilepsy with centrotemporal spikes is a very common epileptic syndrome, seizure visualization is very difficult, and these videos may bring didactical information for recognition of this usual presentation of benign childhood focal epilepsy.

Functional and Structural Network Disorganizations in Typical Epilepsy With Centro-Temporal Spikes and Impact on Cognitive Neurodevelopment

Epilepsy with Centrotemporal Spikes (ECTS) is the most common form of self-limited focal epilepsy. The pathophysiological mechanisms by which ECTS induces neuropsychological impairment in 15-30% of affected children remain unclear. The objective of this study is to review the current state of knowledge concerning the brain structural and functional changes that may be involved in cognitive dysfunctions in ECTS. Structural brain imaging suggests the presence of subtle neurodevelopmental changes over the epileptogenic zone and over distant regions in ECTS. This structural remodeling likely occurs prior to the diagnosis and evolves over time, especially in patients with cognitive impairment, suggesting that the epileptogenic processes might interfere with the dynamics of the brain development and/or the normal maturation processes. Functional brain imaging demonstrates profound disorganization accentuated by interictal epileptic spikes (IES) in the epileptogenic zone and in remote networks in ECTS. Over the epileptogenic zone, the literature demonstrates changes in term of neuronal activity and synchronization, which are effective several hundred milliseconds before the IES. In the same time window, functional changes are also observed in bilateral distant networks, notably in the frontal and temporal lobes. Effective connectivity demonstrates that the epileptogenic zone constitutes the key area at the origin of IES propagation toward distant cortical regions, including frontal areas. Altogether, structural and functional network disorganizations, in terms of: (i) power spectral values, (ii) functional and effective connectivity, are likely to participate in the cognitive impairment commonly reported in children with ECTS. These results suggest a central and causal role of network disorganizations related to IES in the neuropsychological impairment described in ECTS children.

Benign rolandic epilepsy and generalized paroxysms: A study of 13 patients

PURPOSE

To present a retrospective study of 13 children with benign epilepsy with centrotemporal spikes (BECTS), also known as benign rolandic epilepsy (BRE), associated with generalized spikes and waves as the only EEG manifestation at onset.

METHOD

Charts of children with typical clinical criteria of BRE electroclinically followed-up between February 2000 and February 2015 were reviewed.

RESULTS

Among 309 patients who met the electroclinical criteria of BRE, we identified 13 children who presented with the typical clinical manifestations but who, on the EEG, only had generalized paroxysms at onset that continued along the course of the syndrome. Generalized spike-and-wave discharges were observed in all patients when awake and during sleep (100%). During the evolution no particular electroclinical pattern was observed. The patients responded well to antiepileptic drugs, such as valproic acid and levetiracetam. Outcome was good in all patients.

CONCLUSIONS

We found evidence that patients with BRE may have generalized EEG discharges at onset as the sole manifestation lasting throughout the course of the syndrome. In some, focal paroxysms developed later. The course was benign. In our group of patients, clinical features and evolution were similar to those of typical cases of BRE. Response to valproic acid and levetiracetam was found to be particularly good.

Benign childhood focal epilepsies

The idiopathic focal epilepsies comprise a group of syndromes characterized by focal-onset seizures for which there is no detectable structural brain abnormality and for which there is a proposed functional mechanism for the epilepsy and electroencephalography (EEG) abnormalities. This group includes benign rolandic epilepsy (BRE), benign epilepsy with occipital paroxysms (both early onset and late-onset types), idiopathic photosensitive occipital lobe epilepsy, and some less well-defined syndromes. The limits of the early onset idiopathic occipital epilepsy syndrome are not clear, and perhaps this entity represents part of a larger syndrome group of "autonomic" age-related epilepsies. The term "idiopathic" implies absence of a structural brain lesion and a genetic propensity to seizures. The term "benign" implies that the epileptic seizures are easily treated or require no treatment, show remission without sequelae with ultimate and definitive remission before adulthood, do not have severe or exceedingly disturbing seizures, and have no associated serious intellectual or behavioral disturbances. It may be that a syndrome is benign only when it can be recognized early with reasonable certainty, thereby avoiding unnecessary investigations, overtreatment, and lifestyle restrictions. Although BRE has such characteristic clinical and EEG features to make early recognition possible, this is less constantly so in the other focal idiopathic epilepsy syndromes, where the term "benign" may be inappropriate. Mild and selective neuropsychological impairment may occur even in those with typical syndromes but it is unclear whether such selective deficits outlast the active phase of epilepsy. Sometimes the clinical course may be complicated by obvious cognitive and language impairments. In such cases, the term benign is obviously inappropriate, even when seizures are rare. In most patients with the typical focal idiopathic epilepsy syndromes, medication is not necessary.

Emerging genetic influences in benign epilepsy with centro-temporal spikes - BECTS

BECTS is considered to be the most common childhood epileptic syndrome. Multifactorial inheritance is the most important model accounting for the genetic behavior of the common epilepsies. In recent years, different mutations in genes that control the excitability of neurons have been described. Recent reports on the involvement of the BDNF and ELP4 genes with possible roles in cell motility, migration, and adhesion have provided first insights into the complex molecular bases of childhood focal epilepsies. However, in the most common idiopathic benign childhood epilepsies (BECTS and occipital epilepsies), major breakthroughs are still awaited.

Ictal EEG patterns in epilepsy with centro-temporal spikes

PURPOSE

To describe the EEG pattern of seizures in patients with benign childhood epilepsy with centro-temporal spikes (BCECTS).

METHODS

The clinical and EEG data of 701 BCECTS patients with at least a 3 years follow-up were reviewed from 10 epilepsy centers.

RESULTS

Thirty-four seizures were recorded in 30 patients. Four different ictal EEG patterns (A-D) were identified. The most frequent (pattern A) was characterized by low voltage activity of fast rhythmic spikes, increasing in amplitude and decreasing in frequency, and occurred in 14 children. Pattern B (six patients) was constituted by a discharge of spikes intermixed with sharp waves increasing in frequency and amplitude. Pattern C (seven children) consisted of monomorphic theta which progressively formed a discharge increasing in amplitude and decreasing in frequency. Pattern D (5 children) was characterized by a initial focal depression of the electrical activity, followed by one of the three above described patterns. In 21 out of 28 children, the initial ictal pattern, altered from one pattern to another one. No clinical or EEG feature was predictive of a specific ictal pattern.

DISCUSSION

We failed to identify a unique ictal EEG pattern in our patients with BCECTS. The occurrence of per-ictal features, e.g., initial EEG depression or post-ictal slowing, is common and should not be interpreted with prejudice. Alteration of ictal EEG pattern from one to another is not in conflict with the diagnosis of BCECTS.

Benign focal epilepsies of childhood

Until relatively recently, genetic influences in partial seizures were thought to be of minimal importance. However, with further identification of childhood benign partial seizures it is becoming clear that inheritance plays a major role in the pathogenesis of these seizures. Diagnostic criteria proposed for benign partial seizures include absence of neurologic or intellectual deficits, family history of epilepsy, onset of seizures after age 2 years, stereotyped brief seizures, frequent nocturnal occurrence, spontaneous remission in adolescence, and electroencephalograms (EEGs) demonstrating spikes with a distinctive morphology and localization superimposed on normal background activity. The two most commonly described benign partial epilepsies of childhood are benign Rolandic epilepsy (BRE) and benign occipital epilepsy (BOE). Both disorders begin in childhood, are associated with characteristic EEG patterns, have seizures that are easily controlled with medication, often are familial, and have an excellent prognosis. The other benign partial seizure disorders in children that have been described are not as well studied as BOE and BRE, and the role of inheritance pattern, if any, is less clear.

Childhood absence epilepsy in patients with benign focal epileptiform discharges

Few reports are available of ictal recordings in patients with benign focal epileptiform discharges. The study objective was to estimate the frequency of such recordings and to describe their clinical and electrophysiologic presentation. We performed a retrospective chart review of all patients undergoing routine electroencephalography (EEG) with video during a 10-year period. Among 214 patients with benign focal epileptiform discharges, 5 patients were identified with recorded EEG seizures (2.3%). Epilepsy syndromes included one case of benign focal epilepsy of childhood, three cases of childhood absence epilepsy, and in one case the patient presented with both. Only 1 of the 214 patients (0.4%) had a seizure characteristic of benign focal epilepsy of childhood. A literature review revealed the coexistence of childhood absence and benign focal epilepsy of childhood or benign focal epileptiform discharges within the same patient. These findings suggest that benign focal epilepsy of childhood seizures are rarely recorded during routine EEG, probably because seizures occur during the early morning part of the sleep cycle, which may differ from the brief nap during routine EEG. There was concurrence of generalized spike and wave discharges in these patients. It is unclear whether this is related to a common pathophysiologic factor.

Benign childhood epilepsy with centrotemporal spikes: an ictal EEG

Benign childhood epilepsy with centrotemporal spikes (BECTS) is common during childhood, but there are few reports in the literature recording the EEG during a seizure. We studied an 8-year-old boy with oropharyngeal seizures during wakefulness and sleep. Both his neuropsychomotor development and neurological examination were normal. While awake, the subjects's electroencephalogram (EEG) showed normal background activity and epileptiform activity characterized by spikes in the temporal regions (mid and anterior), central region of the right cerebral hemisphere and in the median central and parietal regions. During sleep, his EEG recorded an epileptic seizure that lasted 46 seconds. In the initial phase, the EEG showed an increase in the number of spikes with higher potential in the median central and parietal regions, followed by slow waves associated with the increase in slow waves in the right hemisphere. This was followed by a brief decrease in amplitude of the background activity, and then by rhythmic, diffuse discharges predominantly in the right centrotemporal region, of sharp waves at 12-13 Hz, with increasing potential. Slow waves of high amplitude then occurred for 5 seconds, and finally very high potential spikes reappeared in the central and temporal regions of the right cerebral hemisphere with normalization of the background activity. During these critical phases of the EEG, clonic lip movements and pouting could be observed with the mouth locked shut, associated with "throat noises," but there were no other motor manifestations. The child did not wake up during the seizure and there were no postictal signs or symptoms. Although there are some aspects in common in recordings of BECTS seizures, such as a reduction in amplitude followed by rhythmic discharges of increasing amplitude, differences exist that possibly correspond to the diverse characteristics of the electrical generators.

[Ictal electroencephalographic subclinical pattern in a case of benign partial epilepsy with centrotemporal spikes]

There are few reports of the ictal pattern of benign partial epilepsy with centrotemporal Spikes (BECTS) in the literature. This paper describes the case of a 7-year-old boy without significant perinatal history or psychomotor development delay. There was positive family history of seizures. Magnetic resonance imaging scans of the head was normal. The patient had a nocturnal isolated seizure, followed by a postictal motor deficit at the left arm. The EEG two days after the seizure showed a normal background activity with spikes in the centrotemporal bilateral area, and two subclinicals rhythmic discharges of spike and wave, with a duration of more than 50 seconds in the right centrotemporal area. This pattern of rhythmic discharge wasn not described in BECTS before.

Ictal electroencephalography in a case of benign centrotemporal epilepsy

The purpose of this research was to publish a complete ictal electroencephalographic (EEG) record of a child with benign centrotemporal epilepsy. The record includes a brief description of the patient's epilepsy syndrome, analysis of interictal and ictal EEG records, and a description of corresponding clinical ictal events. Ictal EEG activity appeared over the right rolandic cortex and spread to adjacent sites. Initial rhythmic activity was followed by bilateral series of sharply contoured slow waves. The electric field of the seizure discharge changed during the seizure. Tangentially oriented dipolar field was found in the middle part of the seizure. Evolution of clinical seizure phenomena roughly corresponded to propagation of the ictal discharge. In terms of topography and electromorphology, this ictal record was similar but not completely identical with those reported previously. Collection of further ictal records in benign rolandic or centrotemporal epilepsy of childhood and other epilepsy syndromes is necessary.

Topographic mapping and clinical analysis of benign childhood epilepsy with centrotemporal spikes

We studied the topographic mapping of the electroencephalography (EEG) of 47 children whose clinical history and course were compatible with typical benign childhood epilepsy with centrotemporal spikes (BCECT). Twenty-nine (62%) patients showed typical dipole fields, with a negative potential field in the centrotemporal region and a positive field in the frontal region. Eighteen children did not demonstrate the typical dipole field. Their non-dipole rolandic discharges were localized in small fields of centrotemporal region. The patients with dipole fields in BCECT had significantly less frequent seizures than patients without dipole fields. Twelve of the 47 patients with BCECT (26%) had more than one EEG focus. The clinical courses of patients with multiple foci were not worse than those of patients with a single focus. We conclude that EEG topographic mapping is helpful in identifying typical or atypical EEG topographic patterns in patients with clinically diagnosed BCECT. We also conclude that the presence of dipole field usually indicates a better clinical course of epilepsy and multiple foci do not mean a poor clinical course.

Rolandic epilepsy and cortical dysplasia: MRI correlation of epileptiform discharges

An 8 year-old girl presented with simple facial motor seizures. Although the electroencephalogram (EEG) demonstrated left hemisphere centrotemporal spikes with features consistent with benign rolandic epilepsy, magnetic resonance imaging (MRI) indicated a left hemisphere focal cortical dysplasia. MRI-assisted EEG dipole analysis of the spikes suggested that the rolandic fissure rather than the focal cortical dysplasia was the origin of the epileptic spike discharge. This noninvasive method may be a useful adjunct in evaluation of some patients with epilepsy and focal superficial cerebral lesions.

Centro-temporal benign epilepsy in Saudi children

A review of 36 interictal EEGs compatible with the diagnosis of benign childhood epilepsy with centro-temporal spikes (BECTS) was made in this study. These children constituted 31% of the children with focal epileptic EEG activity observed in the same period. The dipolic spikes occurred either as a single focus (78%) or as two independent foci with a greater preponderance to the right (22%). The onset of seizures before the age of 5 years (Group I) is 53% and between 6 and 10 years (Group II) is 47%. Clinical evaluation showed that 60% of the patients in Group I and 75% in Group II had lateralized seizures, although all of them were initially diagnosed as nocturnal generalized tonic-clonic seizures. A follow-up study showed 31% complete recovery, 47% seizure-free under medications, 8% occasional seizures, 8% frequent seizures, and the rest 6% had a single seizure without medication. It is therefore concluded that the syndrome is common in Saudi Arabia and is usually unrecognized by the general physicians. The follow-up of our patients so far confirms the excellent prognosis.

Pediatric epilepsy syndromes: an update and critical review

Epilepsy syndromes occupy an important position in the current nosology of the epilepsies, describing and classifying seizure disorders with shared clinical and EEG features. Increasingly, this schema is being refined as new information becomes available and our understanding of etiology and presentation of each syndrome widens. Advances in neuroimaging and neurogenetics have been particularly important and are likely to fundamentally change our concepts of syndrome classification. At present, the International League Against Epilepsy classification of epilepsy syndromes according to presumed localization (partial, generalized, undetermined) and etiology (idiopathic, cryptogenic, symptomatic). In clinical practice, it is often useful to conceptualize epilepsy syndromes according to their usual age at presentation, which greatly facilitates syndrome identification in new patients and recognizes the age-related expression of many childhood epilepsies. Definitional problems exist for many pediatric epilepsy syndromes, particularly the epileptic encephalopathies of early infancy, the benign epilepsies of infancy and childhood, the myoclonic epilepsies of infancy and early childhood, and the idiopathic generalized epilepsies of childhood and adolescence. It is likely that further input from the fields of molecular genetics and neuroimaging will enable the classification of epilepsies to become more etiologically oriented and disease specific.

Electroclinical significance of rolandic spikes and dipoles in neurodevelopmentally normal children

"Centrotemporal" (rolandic) spikes are elemental to the diagnosis of benign rolandic epilepsy (BRE) and may reveal a characteristic dipole distribution. Yet, not all children with rolandic spikes present with clinical seizures. Using additional scalp coverage according to the 10-10 electrode system, we attempted to correlate 2 specific spike features: (a) dipole fields, and (b) exact location of maximum negativity, with the presence or absence of clinical seizures in 42 neurodevelopmentally normal children with rolandic (central) spikes. Thirty-three (79%) presented with seizures. Seventeen of 21 children revealing dipoles (81%) and 16 of 21 patients without dipoles (74%) had seizures. Children with high central (C3/C4) foci were just as likely to present with seizures (10 of 15, 67%) as were those with low central (C5/C6) foci (23 of 27, 85%) (P > 0.10). The majority of our study subjects (27 of 42, 64%) revealed maximum negativity in the low central region (C5/C6), and the dipole feature was as likely to be associated with high central foci (7 of 15, 47%) as with low central foci (14 of 27, 52%). Although rolandic spikes are a reliable indicator of potential epileptogenicity, neither their exact location nor dipolar distribution help to further define the population with clinical seizures.

Autosomal dominant rolandic epilepsy and speech dyspraxia: a new syndrome with anticipation

We describe a family of 9 affected individuals in three generations with nocturnal oro-facio-brachial partial seizures, secondarily generalized partial seizures, and centro-temporal epileptiform discharges, associated with oral and speech dyspraxia and cognitive impairment. The speech disorder was prominent, but differed from that of Landau-Kleffner syndrome and of epilepsy with continuous spike and wave during slow-wave sleep. The electroclinical features of this new syndrome of autosomal dominant rolandic epilepsy resemble those of benign rolandic epilepsy, a common inherited epilepsy of childhood. This family shows clinical anticipation of the seizure disorder, the oral and speech dyspraxia, and cognitive dysfunction, suggesting that the genetic mechanism could be expansion of an unstable triplet repeat. Molecular studies on this syndrome, where the inheritance pattern is clear, could also be relevant to identifying a gene for benign rolandic epilepsy where anticipation does not occur and the mode of inheritance is uncertain.

Dipole reversal: an ictal feature in a patient with benign partial epilepsy of childhood with centro-temporal spike

We describe the case of a 15-year-old boy who had the diagnosis of benign partial epilepsy of childhood with centro-temporal spike. During the EEG a subclinical electrographic seizure was recorded. The discharges were clearly electropositive in T4 with positive phase reversal between derivations F8-T4 and T4-T6. The whole episode lasted less than one minute (45 sec). The interictal right medio-temporal spikes reemerged after 60 sec and were electronegative in the same location after the end of the electrographic seizures. The mechanisms underlying this uncommon pattern on EEG is not well established.

Imaging studies in partial epilepsy in children and adolescents

We reviewed the results of imaging studies on 111 children and adolescents with partial epilepsy to determine which imaging procedure had the greatest sensitivity and specificity for partial epilepsy in this age range. All cases were classified as idiopathic, lesional, and cryptogenic epilepsy based on the 1989 International League Against Epilepsy Classification. All patients had magnetic resonance imaging (MRI) and 98 also had computed tomography (CT). Thirty patients with negative CT had MRI lesions that were most likely the cause of the epilepsy, and the initial diagnosis of cryptogenic partial epilepsy was changed to lesional partial epilepsy. We concluded that CT use is unwarrantedly common. MRI should be considered the procedure of first choice. CT has a complementary role, and functional neuroimaging should be encouraged.

Diagnosis of childhood seizure disorders

Convulsive epilepsies are generally unmistakable. Absence epilepsies, which are easily recognized by the provocation of an episode during hyperventilation and by the typical features of the EEG, can be overdiagnosed, especially in the child who daydreams in class and has scattered, asymptomatic, epileptogenic EEG changes. As in adults, complex partial seizures in children can be difficult to distinguish from certain behaviors. Several types of benign childhood epilepsies need to be distinguished from the more intractable and lesional childhood epilepsies. Two common examples, benign rolandic epilepsy and benign occipital epilepsy, can be recognized by their unique EEG changes and clinical features. Juvenile myoclonic epilepsy generally does not remit spontaneously but should be recognized because it appears to respond to valproate. Some recurrent nonepileptic events seen in children can be mistaken for seizures, including shuddering attacks, paroxysmal vertigo, breath-holding spells, cardiogenic syncope, night terrors, and movement disorders, such as paroxysmal kinesigenic choreoathetosis.

Sequential EEG mapping may differentiate "epileptic" from "non-epileptic" rolandic spikes

Sequential topographic mapping was performed to differentiate "epileptic" from "non-epileptic" rolandic spikes. Twenty-four children without any indication of organic brain lesion were divided into a group with epilepsy and a group without epilepsy. The group with epilepsy was subdivided into "classical BECT" (benign focal epilepsy of childhood with centro-temporal spikes) and "non-classical BECT." Sequential mapping of the rolandic spikes revealed two different topographic patterns: a pattern of stationary potential fields and a pattern of non-stationary potential fields. The topographic pattern of stationary potential fields was morphologically represented by a single spike-and-wave complex whereas that of non-stationary potential fields was morphologically represented by a "double" spike-and-wave complex. Among the non-stationary topographic patterns represented by a "double" spike, one specific sequence of changes of potential fields was found. This sequence started with a dipolar field, with the negative pole in the frontal region and the positive pole in the centro-temporal region, morphologically represented by the small first spike of the "double" spike-and-wave complex. This dipolar field, changes to a unipolar or dipolar field, with a negative potential field in the centro-temporal region and, sometimes, a simultaneous positive potential field in the frontal region, morphologically represented by the prominent rolandic spike. This characteristic pattern was found to be significantly related to classical BECT.