Generalized onset seizures with focal evolution (GOFE) — A unique seizure type in the setting of generalized epilepsy

PurposeWe report clinical and electrographic features of generalized onset seizures with focal evolution (GOFE) and present arguments for the inclusion of this seizure type in the seizure classification.MethodsThe adult and pediatric Epilepsy Monitoring Unit databases at Vanderbilt Medical Center and Children's Hospital were screened to identify generalized onset seizures with focal evolution. We reviewed medical records for epilepsy characteristics, epilepsy risk factors, MRI abnormalities, neurologic examination, antiepileptic medications before and after diagnosis, and response to medications. We also reviewed ictal and interictal EEG tracings, as well as video-recorded semiology.ResultsTen patients were identified, 7 males and 3 females. All of the patients developed generalized epilepsy in childhood or adolescence (ages 3–15 years). Generalized onset seizures with focal evolution developed years after onset in 9 patients, with a semiology concerning for focal seizures or nonepileptic events. Ictal discharges had a generalized onset on EEG, described as either generalized spike-and-wave and/or polyspike-and-wave discharges, or generalized fast activity. This electrographic activity then evolved to focal rhythmic activity most commonly localized to one temporal or frontal region; five patients had multiple seizures evolving to focal activity in different regions of both hemispheres. The predominant interictal epileptiform activity included generalized spike-and-wave and/or polyspike-and-wave discharges in all patients. Taking into consideration all clinical and EEG data, six patients were classified with genetic (idiopathic) generalized epilepsy, and four were classified with structural/metabolic (symptomatic) generalized epilepsy. All of the patients had modifications to their medications following discharge, with three becoming seizure-free and five responding with > 50% reduction in seizure frequency.ConclusionGeneralized onset seizures may occasionally have focal evolution with semiology suggestive of focal seizures, leading to a misdiagnosis of focal onset. This unique seizure type may occur with genetic as well as structural/metabolic forms of epilepsy. The identification of this seizure type may help clinicians choose appropriate medications, avoiding narrow spectrum agents known to aggravate generalized onset seizures.     

Relationship between brain glucose metabolism positron emission tomography (PET) and electroencephalography (EEG) in children with continuous spike-and-wave activity during slow-wave sleep

We studied the relationship between brain glucose metabolism patterns and objectively measured interictal epileptiform abnormalities in six children with intractable epilepsy and continuous spike-and-wave activity during slow-wave sleep. Five of the six patients showed lateralized positron emission tomographic (PET) findings, with the hemisphere showing a relative increase in glucose metabolism concordant with the presumed origin of the generalized interictal spike activity delineated by quantitative electroencephalographic (EEG) analysis. One of these five patients achieved seizure freedom following cortical resection involving the areas of unilateral multifocal hypermetabolism, and another patient has been approved for cortical resection. The results in the present study add further support to the hypothesis that the generalized spike-waves in most cases of continuous spike-and-wave activity during slow-wave sleep are the result of secondary bilateral synchrony. Resective surgery can be effective in selected patients with uncontrolled seizures associated with continuous spike-and-wave activity during slow-wave sleep provided that there is concordance between focal abnormalities on PET and EEG.     

Learning Disabilities in Epilepsy: Neurophysiological Aspects

Summary: Subclinical generalized spike-wave discharges are often accompanied by transitory cognitive impairment, demonstrable by psychological testing during EEG recording. Transitory cognitive impairment is demonstrated most readily by difficult tasks and during generalized regular spike-wave bursts lasting for more than 3 s, but can also be found during briefer and even focal discharges. That this is not simply a consequence of global inattention is shown by the fact that focal discharges exhibit some specificity: left-sided focal spiking is more likely to produce errors on verbal tasks, for instance, whereas right-sided discharges are more often accompanied by impairment in handling nonverbal material. Both learning difficulties in general and specific abnormal patterns of cognitive functioning are well documented in children with epilepsy and are most pronounced in those with frequent interictal discharges. However, there is now evidence that intermittent cognitive impairment due to the discharges themselves contributes significantly to such neurophysiological abnormalities. The significance of transitory cognitive impairment accompanying subclinical EEG discharges for everyday functioning is uncertain, but there is experimental evidence that subclinical discharges may be accompanied by disruption of educational skills in children or by impairment of driving performance in motorists. In some individuals, suppression of discharges by antiepileptic drugs has demonstrably improved psychological function, but further work is required to determine the indications for such treatment     

Prediction of Surgical Outcome by Interictal Epileptiform Abnormalities During Intracranial EEG Monitoring in Patients with Extrahippocampal Seizures

PURPOSE: Ictal intracranial EEG recordings obtained during continuous preoperative monitoring are often used to localize the region of seizure onset for purposes of surgical resection in patients with extrahippocampal seizures. Whether interictal epileptiform abnormalities during long-term monitoring can predict surgical outcome in this group is not established. METHODS: Intracranial EEGs of patients who underwent extrahippocampal resective epilepsy surgery were reviewed for interictal epileptiform abnormalities before medication discontinuation or first seizure occurrence. Interictal abnormalities were categorized as within or beyond the confines of surgical resection. We correlated these findings with the region of seizure onset, the pathologic substrate, and surgical outcome (by using Engel criteria) at 1-year minimum follow-up. RESULTS: Of 13 patients with interictal epileptiform abnormalities, six patients had interictal epileptiform discharges extending beyond the confines of surgical resection. These patients all had poor surgical outcome even if the region of electrographic seizure onset was resected. Seven patients had focal interictal epileptiform discharges, the entire extent of which were resected. All had good outcomes. All patients with structural lesions had focal interictal epileptiform abnormalities and good surgical outcomes. The spatial extent of interictal epileptiform discharges varied among patients with nonstructural lesions. However, those whose regions of interictal epileptiform abnormality were included in surgical resection also had good surgical outcome. CONCLUSIONS: The presence of interictal epileptiform discharges extending beyond the area of resection correlates with poor surgical outcome in patients with extrahippocampal epilepsy. In contrast, patients with focal interictal epileptiform discharges included in surgical resection have good surgical outcomes.     

Neurophysiology of juvenile myoclonic epilepsy

Juvenile myclonic epilepsy (JME) can be firmly diagnosed by a careful interview of the patient focusing on the seizures and by the EEG with the help, if necessary, of long-term video-EEG monitoring using sleep and/or sleep deprivation. Background activity is normal. The interictal EEG shows diffuse or generalized spike-wave (SW) and polyspike-wave (PSW) discharges. In some patients, non-specific changes or misleading features such as focal changes are found. Changes are mostly seen at sleep onset and at awakening. Provoked awakenings are more likely to activate interictal paroxysmal abnormalities than spontaneous awakenings. The presence of a photoparoxysmal response with or without myoclonic jerks (MJ) is common (30% of the cases). Myoclonic jerks are associated with a discharge of fast, irregular, generalized PSWs that predominate anteriorly. Myoclonic jerks appear to be associated with rhythmic EEG (spike) potentials at around 20 Hz. These frequencies are in the range of movement-related fast sensorimotor cortex physiological rhythms. The application of jerk-locked averaging technique has provided findings consistent with a cortical origin of MJ. Paired TMS (transcranial magnetic stimulation) studies showed a defective intracortical inhibition, due to impaired GABA-A mediated mechanisms. In this review, we present the EEG characteristics of JME with particular emphasis on the pathophysiology of MJ and on the role of sleep deprivation on interictal and ictal changes.This article is part of a supplemental special issue entitled Juvenile Myoclonic Epilepsy: What is it Really?     

The evaluation of interictal focal EEG findings in adult patients with absence seizures

PurposeTo investigate the focal interictal EEG abnormalities in adult patients with absence seizures (ASs) and to identify their clinical, EEG and semiological correlates.MethodsFifty patients older than 18 years, diagnosed as having IGE with AS documented with ictal recordings. Interictal focal sharp or spike–waves and strictly focal paroxysmal slow activity were considered as focal EEG features. The patients having focal EEG features were classified as “Group I”, whereas the remaining of them was classified as “Group II”.ResultsWe observed focal findings in 34% of the patients, mainly in frontotemporal (41%), and frontal (29%) regions. There were no significant differences with respect to the clinical parameters such as sex, epilepsy duration, positive family history and the age of the onset between the groups. Psychiatric co-morbidities were significantly higher in Group I when compared to Group II (P = 0.00). Accompanying automatisms were higher in Group I, whereas eye deviation during absences was higher in Group II. In Group I, the asymmetry of the ictal discharges was more frequently observed. Focal EEG features were more frequently seen in juvenile absence epilepsy syndrome, without reaching a significance level.ConclusionThe focal findings in adult absence epilepsy patients could have some unknown etio-pathogenetic and prognostic implications. We emphasize the cautious interpretation of isolated interictal focal EEG abnormalities to prevent a wrong diagnosis of focal epilepsy in patients who may indeed suffer from generalized epilepsy.     

Coexistence of symptomatic focal and absence seizures: Video-EEG and EEG-fMRI evidence of overlapping but independent epileptogenic networks

The distinction between typical absences and hypomotor seizures in patients having frontal lesions is difficult. In focal epilepsy, generalized-like interictal discharges can reflect either a coexistent generalized epileptic trait or a secondary bilateral synchrony. Using combined measures of the EEG and blood oxygenation level dependent (BOLD) activity, we studied a 50-year-old patient with both absence-like and symptomatic focal motor seizures. Focal activity induced activation in the lesional area and deactivation in the contralateral central cortex. Generalized spike-and-wave discharges (GSWDs) resulted also in perilesional activation, and multifocal symmetrical cortical and thalamic activations, and deactivation in associative cortical areas. Although the central cortex was involved during both types of epileptic activity, electroencephalography (EEG)–functional magnetic resonance imaging (fMRI) revealed distinct neuronal networks at the time of the focal or generalized discharges, allowing a clear-cut differentiation of the generators. Whether the patient had distinct epileptic syndromes or distinct electrographic patterns from the lesional trigger remains debatable.     

Landau–Kleffner syndrome: A study of 29 patients

PurposeThe aim of the study was to retrospectively analyze the electroclinical features, etiology, treatment, and prognosis of 29 patients with Landau–Kleffner syndrome (LKS) with a long-term follow-up.MethodsInclusion criteria were a diagnosis of LKS with: (1) acquired aphasia or verbal auditory aphasia; (2) with or without focal seizures, secondarily generalized tonic-clonic seizures, absences, or atonic seizures.ResultsMean follow-up was 12 years. All cases except six had seizures. Before the onset of aphasia, developmental language and behavioral disturbances were present in 19 and 14 patients, respectively. All patients had verbal auditory agnosia. Aphasia was severe in 24 patients and moderate in five. Nonlinguistic cognitive dysfunctions were moderate in 14 patients. Behavioral disturbances were found in 16 patients. During the continuous spike-and-wave discharges during slow sleep phase, the spike-wave index was >85% in 15, 50–85% in eight, and 30–50% in four. In two patients, the EEG recording showed occasional bilateral spikes, without continuous spike-and-wave discharges during slow sleep. In this phase, the awake EEG recording showed more frequent interictal abnormalities, predominantly in the temporal regions. Eight patients recovered language completely, but the remaining patients continue to have language deficits of different degrees.ConclusionLandau–Kleffner syndrome is an epileptic encephalopathy characterized by acquired verbal auditory aphasia and seizures in most of the patients associated with continuous or almost continuous spike-and-wave discharges during slow wave sleep. The most commonly used treatments were clobazam, ethosuximide, sulthiame. High-dose steroids were also administered. Adequate and early management may avoid language and cognitive deterioration.     

Seizure characterization and electroencephalographic features in Glut-1 deficiency syndrome

PURPOSE: To characterize seizure types and electroencephalographic features of glucose transporter type 1 deficiency syndrome (Glut-1 DS). METHODS: Twenty children with clinical and laboratory features of Glut-1 DS were evaluated. Age at seizure diagnosis, seizure classification, and response to treatment were determined by chart review. Thirty-two continuous 24-h EEG monitoring sessions and reports of 42 routine EEG studies were assessed. RESULTS: Age at seizure diagnosis was between 4 weeks and 18 months (mean, 5 months). Seizure types were generalized tonic or clonic (14), absence (10), partial (nine), myoclonic (six), or astatic (four). During 24-h EEGs, background activity showed generalized 2.5- to 4-Hz spike-wave discharges (41%), generalized slowing or attenuation (34%), no abnormalities (34%), focal epileptiform discharges (13%), or focal slowing or attenuation (9%). No seizures were captured during 69% of the studies; the remainder had absence (19%), myoclonic (9%), or partial seizures (3%). On evaluation of routine and 24-h EEG studies, focal epileptiform discharges (24%) and slowing (11%) were more frequent in ages 0-24 months. In older children (2-8 years), generalized epileptiform discharges (37.5%) and slowing (21%) were more common. CONCLUSIONS: In all ages, a normal interictal EEG was the most common EEG finding. When abnormalities occurred, focal slowing or epileptiform discharges were more prevalent in the infant. In older children (2 years or older), a generalized 2.5- to 4-Hz spike-wave pattern emerged. Seizure types observed included, absence, myoclonic, partial, and astatic.     

Restless Leg Syndrome in ADHD children: levetiracetam as a reasonable therapeutic option

The comorbidity of Attention Deficit Hyperactivity Disorder (ADHD) with sleep disorders has been extensively studied. In particular, Restless Legs Syndrome (RLS) appears to be consistently more frequent in children with ADHD. Several papers also draw attention to the frequent occurrence of epileptic seizures and EEG abnormalities in ADHD children. We performed a preliminary open label study to evaluate the efficacy of Levetiracetam (LEV) to ameliorate the sleep pattern and reduce RLS symptoms in children with a complex comorbidity between Attention Deficit Hyperactivity Disorder (ADHD), RLS and focal interictal epileptic discharges (IEDs) on EEG. We recruited seven children (all males, aged between 5 and 12 years) who fulfilled the following criteria: ADHD diagnosis combined subtype; presence of idiopathic RLS; and presence of focal IEDs on EEG. All children were given LEV at a starting dose of approximately 10-20 mg/kg/day followed by 10 mg/kg/day incrementing at 1-week intervals up to 50-60 mg/kg/day given in two separate doses. At a 3 and 6 month follow-up, all children showed significant improvement (p < 0.05) in global International RLS Rating Scale (IRLS-RS). Parents’ reports revealed improved sleep quality with fewer awakenings and restorative sleep in their children. LEV was well tolerated and no major side effects were reported. With an accessory report we observed the reduction of epileptiform EEG activity during sleep. In most patients (6 on 7) the discharges completely disappeared; in the last patient epileptiform EEG activity was significantly reduced. These children may represent a subgroup of ADHD patients in which the hyperactivity and attention difficulties might be aggravated by sleep disturbances and by IEDs. LEV could represent a therapeutic option for these comorbid conditions.     

When might hemispheric favouring of epileptiform discharges begin?

PURPOSE: EEG studies based on adult populations report interictal epileptiform discharges (EDS) favour the left hemisphere. It is not clear when favouring becomes apparent as similar paediatric studies have not been performed. METHODS: The authors reviewed 1,579 paediatric EEG interpretations for evidence of hemispheric favouring of focal epileptiform discharges. Analysis focused on first-time EEG results. RESULTS: Right hemispheric favouring of interictal epileptiform discharges occurs in childhood, it remits around 5 years of age whereupon left-sided favouring occurs more frequently (P=0.004, Fisher's Exact). CONCLUSION: Hemispheric vulnerabilities to interictal focal epileptiform activity may display discrete age-related favouring. These findings are discussed in context of normal hemispheric maturation.     

Long-term changes in electroencephalogram findings in a girl with a nonsense SMC1A variant: A case report

IntroductionPathogenic truncating variants in SMC1A, which is located on chromosome Xp11.2, are known to cause infantile-onset epilepsy and severe intellectual disability in girls. Several studies have reported a correlation between SMC1A truncations and seizure clustering; however, the associated electroencephalogram (EEG) patterns remain largely unknown.Case presentationWe investigated an 12-year-old girl who had developed epilepsy at the age of 4 months. The patient experienced unknown onset, tonic-clonic seizures that occurred in clusters several times a week. Her interictal EEG at the age of 2 years showed paroxysmal, generalized, high-amplitude slow waves, whereas epileptiform discharges were scarce. The patient’s interictal EEG gradually deteriorated; at the age of 11 years, diffuse continuous spike-and-wave discharges were predominantly observed in the left temporal region and were particularly obvious in the awake state. Although the unknown onset, tonic seizures occurring weekly persisted under multiple antiepileptic medications, the patient did not experience seizure clustering since the age of 9 years. Whole-genome sequencing revealed a de novo known nonsense variant in SMC1A (c.2923C > T, p.R975*).ConclusionOur patient presented with a mild abnormality in the interictal EEG during infancy and early childhood despite frequent seizure clustering. Notably, the patient’s EEG findings gradually deteriorated over time, which was inconsistent with the amelioration of seizure clustering.     

Spike frequency is dependent on epilepsy duration and seizure frequency in temporal lobe epilepsy.

OBJECTIVES: We wanted to investigate factors that are associated with frequency of interictal epileptiform discharges by investigating 303 patients with temporal lobe epilepsy (TLE). METHODS: We included all patients who consecutively underwent the adult presurgical evaluation program at our center and who had intractable, medial TLE with complex partial seizures due to unilateral medial temporal lobe lesions. The interictal EEG samples were automatically recorded and stored on computer. The location and frequency of interictal epileptiform discharges were assessed by visual analysis of interictal EEG samples of 2-minute duration every hour. RESULTS: There were 303 patients (aged 16-63) who met the inclusion criteria. The median interictal epileptiform discharge frequency was 15 IED/h, the median seizure frequency was 4 seizures/month. According to univariate analyses, we found that age at monitoring, epilepsy duration, and higher seizure frequency were associated with higher interictal epileptiform discharge frequency. In the logistic regression analysis, we found that higher seizure frequency (p < 0.001) and longer epilepsy duration (p = 0.007) were independently associated with higher spike frequency, while the age at monitoring was not. CONCLUSIONS: Seizure frequency and epilepsy duration (years of patient's life with seizure activity) were independently associated with IED frequency, suggesting that IED are modulated by seizures.     

The Spectrum of Idiopathic Rolandic Epilepsy Syndromes and Idiopathic Occipital Epilepsies: From the Benign to the Disabling

Summary:  Benign childhood epilepsy with centrotemporal spikes (BCECTS) is an idiopathic focal epilepsy syndrome, the benign characteristics of which are debated; in fact, stable or intermittent specific neuropsychological deficits are frequent and may affect scholastic or adaptive abilities. Cognitive dysfunction may be related to a marked increment of the interictal epileptic discharges in NREM sleep: different degrees of neuropsychological deficits depend on the extent of awake and sleep activity and the predominant discharge localization. The age of onset and duration of atypical sleep EEG patterns may correlate with permanent cognitive impairments. These atypical clinical and EEG evolutions have been reported in the literature as different syndromes that constitute the spectrum of idiopathic rolandic epilepsy. Moreover, a clinical link between BCECTS and early-onset benign childhood occipital epilepsy has been demonstrated.
According to the neurobiological approach, the spectrum of Idiopathic Rolandic Epilepsy is based on an age-dependent, idiopathic predisposition to focal seizures and sharp-wave discharges, as an expression of nonlesional cortical excitability. The involvement of a given area of the cerebral cortex may depend on the brain maturational stage.     

Gabapentin as add-on therapy in focal epilepsy: a computerized EEG study.

OBJECTIVES: Gabapentin (GBP) possesses a well documented clinical efficacy in those types of focal epilepsy otherwise resistant to conventional antiepileptic drugs (AEDs); on the basis of this, it appears important to investigate the drug effects on the EEG epileptiform and background activity. METHODS: Twenty-five patients with cryptogenic or symptomatic partial epilepsy resistant to conventional AED treatment were included in the study. All patients underwent long-term video-EEG recordings before and after GBP addition (900-1200 mg/day). RESULTS: Quantitative analysis of the interictal EEG paroxysms revealed that GBP had no effect on the rate of occurrence of interictal and ictal EEG abnormalities. GBP was active in delimiting the spatial extent of the interictal spiking activity in those patients who displayed a significant reduction (> or =50%) in seizure occurrence (32% of the patients). EEG background activity recorded under rest condition from 18 out of 25 epileptic patients, before GBP therapy, was characterised by a higher content of the slow spectral components (delta and theta) with respect to control subjects. After GBP addition, the increase of theta relative power was also evident during task performance. CONCLUSIONS: These findings suggest that GBP does not interfere with the generation of interictal EEG spiking while it appears to reduce the susceptibility to seizures concomitantly with a limiting effect on the spiking activity spatial extent. The utilization of GBP in controlling focal seizures is reinforced by the absence of negative influence on cognitive functioning.     

Unitary activity recorded concurrently in primary and secondary temporal epileptic foci of the monkey

To determine the pattern of unitary activity in secondary epileptic foci of Macaca mulatta when situated in association cortex, aluminium hydroxide cream was applied unilaterally to the inferotemporal cortex. When secondary abnormal discharges (transmitted or independent) were observed in the EEG, recordings were taken of mass and extracellular unit activity in both primary and secondary foci. All units situated in the cortex from which mass spike activity could be recorded changed their discharge frequency time-locked to the mass event: a decrease in firing frequency starting 20 to 50 ms after the peak of the mass spike and ending 100 to 300 ms later was invariably present; about half the units also increased their rate of discharge either before or after the decrease. No unit in cortex free of mass spike activity showed any change in firing frequency time-locked to the spikes from the opposite hemisphere. All changes in unitary firing lagged about 20 ms on the peaks of interictal mass spikes; but with ictal spikes an early increase in firing rate coincided with the spike peaks. The changes in firing time-locked to mass events were not associated with the type of spontaneous unitary activity. No difference was found in the behavior of units in primary or secondary foci, or in relation to the age or evolution of a focus.     

Brain perfusion SPECT and EEG findings in children with autism spectrum disorders and medically intractable epilepsy

Objective: We performed brain perfusion single-photon emission computed tomography (SPECT) to detect the abnormal brain region in children with both autism spectrum disorders (ASD) and medically intractable epilepsy. Methods: Fifteen children aged 4–16 years underwent multimodal examinations (MRI, interictal and/or ictal ECD-SPECT, EEG and MEG) to investigate their indications for surgical treatment. All children were diagnosed with ASD according to DSM-IV criteria and intractable epilepsy. Despite medical treatment for more than a year, all experienced at least one seizure per month. All had no underlying basic disorders. Each SPECT result was statistically analyzed by comparing with standard SPECT images obtained from our institute (easy Z-score imaging system; eZIS). The relationship between the eZIS pattern and EEG abnormalities or clinical symptoms was investigated. Results: All children showed focal abnormal patterns on eZIS and focal spikes on EEG. In all children, eZIS revealed a mixed hypoperfusion pattern, especially in the prefrontal cortex, medial frontal cortex, anterior cingulate cortex, medial parietal cortex, and/or anterior temporal cortex. In seven of 12 children who underwent interictal SPECT studies, areas of hypoperfusion were related to the focus observed on EEG; in six children, the focal EEG spikes represented areas of hyperperfusion. The children were divided into two groups according to the main type of hypoperfusion patterns seen on eZIS; medial-cingulate type and temporal type. No significant relationship was observed between the areas of hypoperfusion and clinical symptoms. eZIS showed the epileptic focus clearly on ictal SPECT. Conclusions: SPECT was useful to detect the abnormal brain region not only in searching for the epileptic focus but also in assessing the low or high functioning region of the brain.     

Absence of seizures despite high prevalence of epileptiform EEG abnormalities in children with autism monitored in a tertiary care center

PURPOSE: Children with autism are commonly referred for video-EEG monitoring to determine the precise nature of their seizure-like events. METHODS: We studied 32 children with autism by using continuous video-EEG telemetry (VEEG) monitoring at a tertiary care referral center. RESULTS: Of the 32 total patients, 22 were primarily referred for seizure evaluation and 10 for 24-h interictal EEG recording. Studies in two additional patients were prematurely terminated because of intolerance (they are not included in the analyses). The median monitoring duration was 1 day (range, 1-7 days). Of 22 patients referred for seizure evaluation, 15 had recorded events, but none was an epileptic seizure; the other seven patients had no recorded events. Interictal epileptiform EEG abnormalities were detected in 19 (59%) of 32 patients. These abnormalities included focal sharp waves (in eight patients), multifocal sharp waves (in six patients), generalized spike-wave complexes (in 11 patients), and generalized paroxysmal fast activity/polyspikes (in two patients). Focal/multifocal and generalized epileptiform abnormalities coexisted in six patients. Notably, 11 (73%) of the 15 patients with nonepileptic events had interictal epileptiform EEG abnormalities. CONCLUSIONS: Video-EEG evaluation of children with autism reveals epileptiform EEG abnormalities in the majority. However, many recorded seizure-like events are not epileptic, even in children with epileptiform EEG abnormalities.     

Acute cognitive effects of nonconvulsive difficult-to-detect epileptic seizures and epileptiform electroencephalographic discharges

This study compares the acute cognitive effects of short nonconvulsive seizures with the effects of interictal epileptiform electroencephalographic (EEG) discharges in children. The study is a prospective, standardized, nonrandomized, and open clinical comparative study. Eligible patients were included when they had (a) unclear seizures and fluctuations in cognitive performance and (b) frequent epileptiform EEG discharges in a recent EEG. All children were assessed with EEG/video (Brainlab) simultaneously with computerized neuropsychologic testing (FePsy) assessing motor speed/alertness, mental speed/attention, and memory function. Eleven patients with short nonconvulsive seizures during cognitive testing were included and compared with 11 matched patients with interictal epileptiform EEG discharges during cognitive testing but without seizures. Patients included in both groups had a reconfirmed diagnosis of epilepsy. Cognitive performance for both groups was compared. Statistical analysis showed significant correlations between the number of seizures (during cognitive testing) and impaired alertness and between the duration of the ictal period and memory impairment. Interictal epileptiform EEG discharges do not have an additional independent effect on cognitive function. The results demonstrate the accumulating cognitive effect of seizures and illustrate that frequent seizures, even when these are short in duration and with subtle symptomatology, can have a substantial impact on daily life and can lead to state-dependent learning impairment. Alertness and short-term memory appeared to be the functions that are most vulnerable for the acute effects of seizures.     

The investigation of EEG specificity in epileptic children during Depakine therapy

Background: Antiepileptic drug (AED) therapy in epileptic children can be optimized via an anticipation of AED efficacy during early stages of therapy. We hypothesize that the comprehensive electroencephalography (EEG) evaluation can determine AED efficacy in epileptic children. Thus, this study aimed to investigate the alteration of characteristics of interictal EEG during the AED therapy. Methods: Forty-three children aged 3–9 were investigated. EEGs were recorded three times: prior to valproic acid-Depakine (Dep) monotherapy and twice under the Dep therapy (at three and six/eight months). Baseline EEG was analyzed for quantitative characteristics of interictal EEG, such as absolute values of the power (AVP) spectra and EEG topography/brain mapping. The study involved epileptiform EEG and clinical condition assessments. Results: Dep decreased AVP spectra in a low-frequency range, suppressed spontaneous epileptic discharge, and spike-wave complex 3/s. Dep partially decreased spikes-polyspikes, sharp waves, and generalized paroxysmal bursts during functional trials. Dep did not diminish rhythmic monomorphic theta-waves (RMT) of tempo-parietal localization observed by brain mapping. The presence of RMT correlated with the reocurrence of seizures if Dep was withdrawn. Conclusions: The findings of this study suggest that the presence of RMT with tempo-parietal localization on the interictal EEG can anticipate reocurrence of seizures if Dep dose will be reduced or withdrawn. The efficacy of the AED therapy can be revealed via reduction of low-frequency waves and suppression of epileptiform EEG elements parallel to clinical improvement. Thus, optimal treatment strategies can be tailored based on the evaluation of background EEG characteristics using spectral analysis, EEG mapping, and the quantitative EEG approach.