Benign Focal Epileptiform Discharges Research Articles

Index of benign focal epileptiform discharges of childhood and specificity of cognitive functions development in children: А retrospective study

Index of benign focal epileptiform discharges of childhood and specificity of cognitive functions development in children: А retrospective study

The Role and Controversies of Electroencephalogram in Focal versus Generalized Epilepsy

AbstractAs early in 1935, Gibbs et al described electroencephalogram (EEG) features of large slow waves seen in “petit mal” seizures and change in background rhythm to a higher frequency, greater amplitude pattern in “grand mal” seizures. Studies have shown many typical EEG features in focal onset as well as generalized epilepsies.2 3 It is usually easy to delineate focal epilepsy cases when EEG onset of seizures is clear as seen in Benign focal epileptiform discharges of childhood.4 However, it is not uncommon to see cases where epileptiform discharges are not very clear. For example, there can be secondary bilateral synchrony or generalized onset of epileptiform discharges in some cases of focal epilepsy5 and nongeneralized EEG features is cases of generalized epilepsy like absence seizures.6 The awareness of occurrence of focal clinical and EEG features in generalized epilepsy is particularly important to help to select appropriate AEDs and also to avoid inappropriate consideration for epilepsy surgery.7 Lüders et al8 have shown that multiple factors like electroclinical seizure evolution, neuroimaging (both functional and anatomical) have to be analyzed in depth before defining an epileptic syndrome. Here, we are providing few examples of different situations where it is still mysterious to figure out focal onset seizures with secondary generalization versus primary generalized epilepsy.

The course and development of epilepsy in patients with typical variant of Rett syndrome and mutations

To study the anamnesis, clinical state, electro-encephalographic and brain MRI characteristics in patients with Rett syndrome (МЕСР2) and epilepsy. Eleven female patients, aged from 3 to 23 years, with Rett syndrome and MeCP2 mutations were studied. The study continued for 10 years (2006-2015). Assessment of neurological and mental status, night sleep video-EEG monitoring, MRI were performed. Epilepsy was diagnosed in six cases (54.5%). Mean age at onset of epileptic seizures was 3 years 9 month. The following types of seizures were described: generalized, myoclonic, myotonic, tonic, versive, focal motor, atypical absences. Status epilepticus developed in one patient. Generalized seizures were identified in 56.25%, focal seizures in 43.75%. EEG changes were found in 9 patients (81.8%): slowing of the activity, episodes of periodic regional slowing, regional epileptiform activity and diffuse epileptiform activity, benign focal epileptiform discharges (BFED) of childhood, multiregional epileptiform activity. Five patients were treated with antiepileptic drugs. All of them had improved during treatment: a reduction of frequency of seizures was up to 50% in 4 cases (80%). One patient with resistant epilepsy was treated with the combination of drugs (levetiracetam, topiramate, zonisamide, benzodiazepine) that led to stopping of seizures during night sleep and decrease in the frequency of daytime seizures by 50%. Further research of epilepsy and efficacy of antiepileptic drugs in Rett syndrome is required.

The course and the development of epilepsy in patients with typical variant of Rett syndrome and mutations

Studying data of anamnesis, clinical state, electro-encephalographic, brain MRI in patients with Rett syndrome (МЕСР2). We studied 11 patients (female) from three to 23 years old with Rett syndrome and MeCP2 mutations. Observation continued 10 years (2006-2015). We analyzed the results of the neurological status, night sleep video-EEG monitoring, MRI. Epilepsy diagnosed in six cases (54, 5%). The overage age of debut of epileptic seizures was 3 years 9 months. There are some types of seizures: generalized, myoclonic, myotonic, tonic, versive, focal motor, atypical absences. Status epilepticus evolved in one patient. Generalized seizures were 56, 25%, focal seizures - 43, 75%. EEG changing marked in nine patients (81, 8%): slowdown back activity, episodes of periodic regional slowdown, regional epileptiform activity, and diffuse epileptiform activity like benign focal epileptiform discharges (BFED). five patients took antiepileptic drugs. All of them had improved during treatment. There were reducing of frequency of the seizures up 50% - 4 cases (80%). one patients with resistant epilepsy was taken combination of drugs (levetirecetam, topiromat, zonisamide, benzodiazepine) with stopping of seizures in the night sleep and decreasing of frequency of daytime seizures to 50%. We believe there is very important of study epilepsy in patients with Rett syndrome and improvement of its treatment.

EPILEPTIC ENCEPHALOPTHIES WITH ELECTRICAL STATUS EPILEPTICUS SLOW SLEEP (ESES)

Complex of acquired disturbances of cognitive functions in children associated with continuous epileptiform activity on the EEG is a serious problem. Quite often the EEG patterns in epileptic encephalopathies of childhood such as Landau-Kleffner, pseudo-Lennox syndromes, autistic epileptiform regression etc. are represented by the so-called «benign focal epileptiform discharges of childhood» (BEDOC, BFEDC, BEDC). Epileptiform discharges are characterized by high index and diffuse spreading nature, especially during slow-wave sleep, forming the pattern of ESES. In the treatment of epileptic encephalopathies the following AEDs are applied in monotherapy or rational combined therapy: valproates, ethosuximide, levetiracetam, sultiame and benzodiazepines.

The Clinical and Neurophysiological Features of Epileptic Syndromes Associated with Benign Focal Epileptiform Discharges of Childhood

Benign focal epileptiform discharge of childhood (BFEDC) is an age-dependent pattern determined in electroencephalograms (EEGs), which is associated with idiopathic benign focal epilepsy (BFE). Studies of BFE revealed symptomatic phenocopies in patients with cerebral struc- tural abnormalities in such conditions as infantile cerebral palsy and malformations. Some arguments against the «benign» nature of BFEDC are presented, since BFEDC may impair various cognitive functions and behavior (e.g., cause epileptic encephalophathies). Objective. To determine the clinical and neurophysiological features of epileptic syndromes associated with prolonged epileptiform activity during sleep in children and adolescents, as well as approaches to rational therapy. Patients and Methods . A total of 1862 children aged 2–18 admitted to the specialized Department of Psychoneurology of the Voronezh Regional Children Clinical Hospital No 1 in 2004–2007, who had epileptic seizures and non-epileptic neurological disorders, were exam- ined. The children underwent assessment of the neurological status, neuropsychological assessment, and video-EEG monitoring. The spike- wave index (SWI) was calculated and magnetic resonance imaging (MRI) of the brain was performed to register the epileptiform activity during sleep. Results and Discussion. It was demonstrated that when ISW of BFEDC patterns is >30%, evolution into epileptic encephalopathy was observed in 66% of patients (including epilepsy with electrical status epilepticus in sleep in 49% of patients and cognitive epileptiform disinte- gration in 17% of patients). The results prove the justification of prescribing antiepileptic drugs to patients with SWI ≥30% even if they have no epileptic seizures. Duo-therapy with valproate and ethosuximide or levetiracetam is most the effective therapy. Further prospective studies for children with BFEDC will give new insight into this area.

Epilepsy Surgery Outcome in Coexisting Symptomatic Refractory Focal Epilepsy and Benign Focal Epilepsy of Childhood

Epilepsy surgery may successfully treat refractory symptomatic focal epilepsy in patients with coexisting benign focal epileptiform discharges. Reported here is the outcome after resective epilepsy surgery in three children with pharmacoresistant lesional focal epilepsy in whom seizures of benign focal epilepsy of childhood had been recorded. Two patients had left temporal epilepsy due to a malformation of cortical development; one of these had dual pathology, with additional ipsilateral hippocampal sclerosis. One child had catastrophic left hemispheric epilepsy due to left hemimegalencephaly. Frequent, habitual seizures of symptomatic epilepsy resolved after surgery (follow-up duration, 32-55 months); however, rare benign focal seizures of childhood have continued. These cases demonstrate that lesional pharmacoresistant focal epilepsy can be successfully treated with resective epilepsy surgery even when coexisting with benign focal epilepsy of childhood. During postoperative follow-up, careful documentation of breakthrough seizures due to benign focal epilepsy of childhood is important, so that these patients are not labeled as surgical failures.

Neuroimaging findings in children with benign focal epileptiform discharges

To determine reasons for neuroimaging and neuroimaging findings in children with benign focal epileptiform discharges (BFEDs). We performed a retrospective chart review of children who had BFEDs on routine EEG and underwent brain MRI. We identified 97 patients with BFEDs and MRI. Forty-five of these 97 patients also had seizures consistent with benign focal epilepsy of childhood with centrotemporal spikes (BECTS). Rationale for imaging in the 45 BECTS patients included historical features such as headaches (14), increase in seizure frequency (5), and new events (5). Nine MRIs were obtained prior to referral and 12 for unspecified reasons. MRI findings were not significantly different between BECTS and BFEDs patients. Fourty-one patients (42%) had abnormal findings on MRI, including T2 hyperintensities (10), hippocampal atrophy (6), malformation of cortical development (4), volume loss (5), Chiari malformation (4), and others (18). MRIs are not routinely recommended in patients with BECTS unless atypical features are present. Atypical features which may prompt MRI include change in clinical seizure types or frequency, historical features such as headaches, abnormal neurological exam, and atypical EEG features. 42% of our selected patients had intracranial abnormalities, most of which were of unclear clinical significance. Remote infarcts and early lesions accounted for most MRI findings suggesting they may be related to BFEDs.

Levetiracetam as add-on therapy in different subgroups of “benign” idiopathic focal epilepsies in childhood

Several recent studies have shown that levetiracetam (LEV) can be beneficial in the treatment of children with typical rolandic epilepsy (RE). Reports about the effectiveness of LEV in the treatment of children with the less benign variants in the spectrum of “benign” idiopathic focal epilepsies are still rare. Little is known about the effect of LEV on interictal epileptiform discharges in these syndromes. We report on LEV therapy in 32 children (mean age: 10.6 years, range: 4–14) with RE or variants like atypical benign idiopathic partial epilepsy of childhood (ABIPEC), Landau–Kleffner syndrome (LKS), and continuous spikes and waves during sleep (CSWS) and in children with benign idiopathic focal epileptiform discharges of childhood (BIFEDC). Cognitive and behavioral problems, not seizures, may be related to the pathological EEG. Patients with a reduction in seizure frequency >50% and/or reduction in BIFEDC >90% 3 months after having started LEV therapy were defined as responders. The average dose of LEV was 39 mg/kg body wt per day; LEV was given in monotherapy to 31.3% of the patients. Overall, 20 of 32 patients (62.5%) did benefit: 12 of 24 patients had a >50% reduction in seizure frequency; 2 of 24 patients (8.3%) were completely seizure free; 18 of 32 patients (56.3%) had a >90% reduction in BIFEDC (including CSWS); 6 of 32 (18.8%) had an EEG completely free of epileptiform discharges; and 17 of 32 (53.1%) showed improvement in cognition and/or language functions and/or behavior. Surprisingly, LEV tended to be more helpful in atypical rolandic epilepsies and other variants.

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.

Lateralization of Interictal EEG Findings

Several reports indicate that interictal epileptiform discharges (IED) may be more likely to occur over the left cerebral hemisphere than over the right. The objective of our study was to determine the frequency and type of IED on routine and multihour EEGs in a tertiary epilepsy center to estimate the frequency of left-sided versus right-sided IED and to determine interictal spike distribution pattern differences between adult and pediatric epilepsy patients. The current study retrospectively reviewed 31,207 EEGs (25,793 routine EEGs and 5414 multihour EEGs) recorded on 24,003 patients during the period from 1993 to 2003. All EEGs were read according to a systematic EEG classification system. Every patient was considered only once by including the first abnormal EEG. Regional unilateral or bilateral IEDs were recorded in 1707 patients (7%). Regional unilateral or bilateral slow was recorded in 2297 patients (9.6%). Left-sided regional IED were seen in 828 patients and accounted for 58% of all unilateral IED. Left-sided slow was seen in 1389 patients and accounted for 65% of all unilateral slow. Lateralization of slow was due to intermittent slow, whereas continuous slow involved both hemispheres equally. There was no lateralization difference in benign focal epileptiform discharges of childhood. Lateralization shows a tendency toward greater left-sided lateralization of interictal findings with aging. Benign focal epileptiform discharges were only seen under the age of 20 years old. Regional IEDs were seen in approximately 7% of patients and slowing occurs in 10% of patients. Both abnormalities were seen more frequently in the left hemisphere. Age adjusted analysis of the data revealed that this left-sided predominance was mildly increased in adults as compared with pediatric patients.

Differentiating Between Benign and Less Benign: Epilepsy Surgery in Symptomatic Frontal Lobe Epilepsy Associated With Benign Focal Epileptiform Discharges of Childhood

Benign focal epileptiform discharges of childhood are a genetically determined electroencephalographic trait. Assessment of their clinical relevance in children with epilepsy may be difficult if imaging reveals a lesion congruent or incongruous with the focus of the benign focal epileptiform discharges of childhood. This article reports a boy with parietooccipital benign focal epileptiform discharges of childhood in whom videoelectroencephalography and magnetic resonance imaging disclosed symptomatic frontal lobe epilepsy. Surgical removal of a focal cortical dysplasia in the left frontal lobe yielded freedom from seizures and positive behavioral and cognitive development. Nocturnal benign focal epileptiform discharges of childhood persisted until puberty (follow-up, 50 months). Early diagnostic differentiation of idiopathic syndromes such as idiopathic benign focal epilepsy of childhood from symptomatic focal epilepsies with a potentially less benign course is important. In symptomatic frontal lobe epilepsy, epilepsy surgery may yield an excellent outcome despite the presence of concurrent benign focal epileptiform discharges of childhood.

Benign focal epileptiform discharges in children after severe head trauma: prognostic value and clinical course.

To assess the occurrence and prognosis of benign focal epileptiform discharges (BFED) in EEG after severe head trauma (SHT) in children. Between January 1987 and December 1994, 47 of 828 children with anamnestic SHT showed a single or dominant epileptic focus in EEG. Spike wave localization and morphology were either suggestive for BFED (group I, 21 children) or were suspected to be symptomatic (group II, 26 children). We analyzed the course of epilepsy and epileptic discharges in EEG, neuroradiologic findings, neurologic outcome, and school adjustment. After SHT, spike waves appeared immediately (within 72 h) or delayed (maximum 7 years) and disappeared between ages 3 and 14 years in 14 children of group I and between ages 8 and 23 years in 10 of group II. Children with persistent spike waves in group I were all younger than 14 years; in group II, seven were older than 15 years. Computed tomographic (CT) lesions, ipsilateral to the epileptic focus, were seen in 10 children of group I and 15 of group II. Early seizures occurred in nine children of group I and eight of group II and late-onset seizures in one of group I and nine of group II (p = 0.028). Epilepsy developed in three children of group I and 12 of group II and was drug refractory in six children of group II, all with persistent epileptic foci. Regular schools were attended by 14 (67%) children in group I and 12 (48%) of group II. Benign focal epileptiform discharges in posttraumatic EEGs have the same favorable prognosis as in benign focal epilepsy and should be handled as recommended for classic benign focal epilepsy.

Complex Partial Seizures of Childhood Onset

Few detailed studies have examined the long-term outcome of complex partial seizures (CPS) in children and adolescents. Previous studies have selected patients on clinical criteria only or have included those with benign focal epileptiform discharges of childhood, nonepileptiform sharp transients, and generalized epileptiform discharges. We have followed up 29 patients with clinically and electroencephalographically defined CPS of childhood onset for five years or more. Twelve patients are seizure free, eight of them after having epilepsy surgery. Of the remaining, eight patients have intractable seizures. Only one patient was able to discontinue anticonvulsant therapy after epilepsy surgery. No patient had spontaneous remission of seizures without anticonvulsant medications. School difficulties, behavior problems, and unemployment were seen in half the group. We believe CPS in this age group are difficult to control and need aggressive management. In selected patients, epilepsy surgery offers a good chance of seizure control and improvement of educational, social, and vocational potential.

Benign focal epileptiform discharges in childhood migraine (BFEDC)

Interictal EEGs were studied in 100 children, ages 3 to 15 years. Records were interpreted independent of history; 89% were normal, 9% had benign focal epileptiform discharges (BFEDC), one had temporal spikes, and one had background slowing. The nine patients with BFEDC did not differ from the others. None had epilepsy. This incidence of 9% is higher (p less than 0.0001) than the incidence of BFEDC in the normal population (1.9%). The significance of this finding is not clear, but migraine and benign focal epilepsy of childhood may be genetically linked, or the vascular abnormality of migraine may cause brain injury to produce sharp waves of low epileptogenicity. These results do not suggest that headaches are epileptic.