Reduction of epileptiform activity in response to low-dose clonazepam in children with epilepsy: a randomized double-blind study

Seizure Cycles under Pharmacotherapy

OBJECTIVE

This study was undertaken to determine the effects of antiseizure medications (ASMs) on multidien (multiday) cycles of interictal epileptiform activity (IEA) and seizures and evaluate their potential clinical significance.

METHODS

We retrospectively analyzed up to 10 years of data from 88 of the 256 total adults with pharmacoresistant focal epilepsy who participated in the clinical trials of the RNS System, an intracranial device that keeps records of IEA counts. Following adjunctive ASM trials, we evaluated changes over months in (1) rates of self-reported disabling seizures and (2) multidien IEA cycle strength (spectral power for periodicity between 4 and 40 days). We used a survival analysis and the receiver operating characteristics to assess changes in IEA as a predictor of seizure control.

RESULTS

Among 56 (33.3%) of the 168 adjunctive ASM trials suitable for analysis, ASM introduction was followed by an average 50 to 70% decrease in multidien IEA cycle strength and a concomitant 50 to 70% decrease in relative seizure rate for up to 12 months. Individuals with a ≥50% decrease in IEA cycle strength in the first 3 months of an ASM trial had a higher probability of remaining seizure responders (≥50% seizure rate reduction, p < 10-7) or super-responders (≥90%, p < 10-8) over the next 12 months.

INTERPRETATION

In this large cohort, a decrease in multidien IEA cycle strength following initiation of an adjunctive ASM correlated with seizure control for up to 12 months, suggesting that fluctuations in IEA mirror "disease activity" in pharmacoresistant focal epilepsy and may have clinical utility as a biomarker to predict treatment response. ANN NEUROL 2024;95:743-753.

Prognostic interictal electroencephalographic biomarkers and models to assess antiseizure medication efficacy for clinical practice: A scoping review

Antiseizure medication (ASM) is the primary treatment for epilepsy. In clinical practice, methods to assess ASM efficacy (predict seizure freedom or seizure reduction), during any phase of the drug treatment lifecycle, are limited. This scoping review identifies and appraises prognostic electroencephalographic (EEG) biomarkers and prognostic models that use EEG features, which are associated with seizure outcomes following ASM initiation, dose adjustment, or withdrawal. We also aim to summarize the population and context in which these biomarkers and models were identified and described, to understand how they could be used in clinical practice. Between January 2021 and October 2022, four databases, references, and citations were systematically searched for ASM studies investigating changes to interictal EEG or prognostic models using EEG features and seizure outcomes. Study bias was appraised using modified Quality in Prognosis Studies criteria. Results were synthesized into a qualitative review. Of 875 studies identified, 93 were included. Biomarkers identified were classed as qualitative (visually identified by wave morphology) or quantitative. Qualitative biomarkers include identifying hypsarrhythmia, centrotemporal spikes, interictal epileptiform discharges (IED), classifying the EEG as normal/abnormal/epileptiform, and photoparoxysmal response. Quantitative biomarkers were statistics applied to IED, high-frequency activity, frequency band power, current source density estimates, pairwise statistical interdependence between EEG channels, and measures of complexity. Prognostic models using EEG features were Cox proportional hazards models and machine learning models. There is promise that some quantitative EEG biomarkers could be used to assess ASM efficacy, but further research is required. There is insufficient evidence to conclude any specific biomarker can be used for a particular population or context to prognosticate ASM efficacy. We identified a potential battery of prognostic EEG biomarkers, which could be combined with prognostic models to assess ASM efficacy. However, many confounders need to be addressed for translation into clinical practice.

Clonazepam monotherapy for treating people with newly diagnosed epilepsy

BACKGROUND

Epilepsy is one of the most common neurological disorders worldwide, with an age-adjusted prevalence of 4 to 8 per 1000 population and an age-adjusted incidence of 44 per 100,000 person-years in developed countries. Monotherapy represents the best therapeutic option in people with newly diagnosed epilepsy. This is an updated version of the original Cochrane Review published in 2019, Issue 11.

OBJECTIVES

To assess the efficacy and tolerability of oral clonazepam used as monotherapy for newly diagnosed epilepsy, compared with placebo or a different anti-seizure medication.

SEARCH METHODS

For the latest update of this review we searched the following databases on 14 September 2021: the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid) (1946 to 13 September 2021). CRS Web includes randomized controlled trials (RCTs) or quasi-RCTs from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialized Registers of Cochrane Review Groups, including Epilepsy.

SELECTION CRITERIA

We included RCTs or quasi-RCTs comparing oral clonazepam used as monotherapy treatment versus placebo or a different anti-seizure medication (active comparator) in people of any age with newly diagnosed epilepsy, defined according to the clinical practical definition proposed by the International League Against Epilepsy (ILAE).

DATA COLLECTION AND ANALYSIS

The following outcomes were considered: proportion of participants seizure-free at one, three, six, 12, and 24 months after randomization; proportion of responders (those with at least a 50% reduction in seizure frequency from baseline to end of treatment); proportion of participants with treatment-emergent adverse events (TEAEs) during the treatment period or leading to discontinuation during the treatment period; proportion of dropouts/withdrawals due to side effects, lack of efficacy or other reasons; and improvement in quality of life, as assessed by validated and reliable rating scales. Two review authors independently screened all titles and abstracts to assess the eligibility of publications identified by the searches. We independently extracted data from trial reports and cross-checked them for accuracy. Any disagreements between the two authors regarding data extraction were resolved by discussion and consensus. We scrutinized trials and evaluated the methodological quality of all included studies. We used GRADE assessment criteria to evaluate the certainty of the evidence.

MAIN RESULTS

Two randomized controlled trials had already been included in the previous version of the review, with a total of 115 participants. One study compared clonazepam to carbamazepine as monotherapy for participants with newly diagnosed psychomotor epilepsy (a condition corresponding to what is now termed mesial temporal lobe epilepsy). One study (published as an abstract) compared clonazepam to ethosuximide as monotherapy for children with absence seizures. Based on the available data and the details on methodology provided, we judged both studies as being at unclear or high risk of bias for the domains assessed (apart from the selective reporting (reporting bias) domain - we judged one study as being at low risk of bias and the other study at high risk of bias). In the study comparing clonazepam to carbamazepine, no difference was found between the groups regarding the proportion of participants who were seizure-free at one month after randomization (risk ratio (RR) 1.97, 95% confidence interval (CI) 0.99 to 3.94; 30 participants; very low-certainty evidence), three months after randomization (RR 1.19, 95% CI 0.62 to 2.29; 26 participants; very low-certainty evidence), and six months after randomization (RR 0.50, 95% CI 0.09 to 2.73; 9 participants; very low-certainty evidence). No statistical difference was found between clonazepam and carbamazepine in terms of proportion of participants with TEAEs leading to discontinuation (RR 2.61, 95% CI 0.80 to 8.52; 36 participants; very low-certainty evidence) and in terms of dropouts/withdrawals due to side effects, lack of efficacy or other reasons (RR 1.56, 95% CI 0.61 to 4.02; 36 participants; very low-certainty evidence). The study did not provide any information on our other prespecified outcomes of interest. The study comparing clonazepam to ethosuximide did not provide any data on efficacy. The proportion of dropouts/withdrawal was higher in the group receiving clonazepam compared to the group receiving ethosuximide (RR 3.63, 95% CI 1.12 to 11.74; 79 participants; very low-certainty evidence). No information on other outcomes of interest was provided in this study.

AUTHORS' CONCLUSIONS

We did not find any new studies since the last version of this review. There is only limited and very low-certainty evidence from randomized controlled trials on the efficacy and tolerability of clonazepam used in monotherapy for the treatment of epilepsy. No difference in efficacy and tolerability was found in a small trial comparing clonazepam to carbamazepine for the treatment of mesial temporal lobe epilepsy. Clonazepam was less well tolerated than ethosuximide in a trial of children with absence seizures, however no comparative data on efficacy were provided. There is currently insufficient evidence to support the use of clonazepam as monotherapy treatment for epilepsy.

Measuring the effects of first antiepileptic medication in Temporal Lobe Epilepsy: Predictive value of quantitative-EEG analysis

OBJECTIVE

To determine the quantitative EEG responses in a population of drug-naïve patients with Temporal Lobe Epilepsy (TLE) after Levetiracetam (LEV) initiation as first antiepileptic drug (AED). We hypothesized that the outcome of AED treatment can be predicted from EEG data in patients with TLE.

METHODS

Twenty-three patients with TLE and twenty-five healthy controls were examined. Clinical outcome was dichotomized into seizure-free (SF) and non-seizure-free (NSF) after two years of LEV. EEG parameters were compared between healthy controls and patients with TLE at baseline (EEG^pre) and after three months of AED therapy (EEG^pre-post) and between SF and NSF patients. Receiver Operating Characteristic curves models were built to test whether EEG parameters predicted outcome.

RESULTS

AED therapy induces an increase in EEG power for Alpha (p = 0.06) and a decrease in Theta (p < 0.05). Connectivity values were lower in SF compared to NSF patients (p < 0.001). Quantitative EEG predicted outcome after LEV treatment with an estimated accuracy varying from 65.2% to 91.3% (area under the curve [AUC] = 0.56-0.93) for EEG^pre and from 69.9% to 86.9% (AUC = 0.69-0.94) for EEG^pre-post.

CONCLUSIONS

AED therapy induces EEG modifications in TLE patients, and such modifications are predictive of clinical outcome.

SIGNIFICANCE

Quantitative EEG may help understanding the effect of AEDs in the central nervous system and offer new prognostic biomarkers for patients with epilepsy.

Clonazepam add-on therapy for drug-resistant epilepsy

BACKGROUND

This is an updated version of the original Cochrane Review published in 2018, Issue 5. Epilepsy affects over 70 million people worldwide, and nearly a quarter of patients with seizures have drug-resistant epilepsy. People with drug-resistant epilepsy have increased risks of premature death, injuries, psychosocial dysfunction, and a reduced quality of life.

OBJECTIVES

To assess the efficacy and tolerability of clonazepam when used as an add-on therapy for adults and children with drug-resistant focal onset or generalised onset epileptic seizures, when compared with placebo or another antiepileptic agent.

SEARCH METHODS

For the latest update we searched the following databases on 4 June 2019: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid) 1946 to 3 June, 2019. The Cochrane Register of Studies (CRS Web) includes the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and randomised or quasi-randomised, controlled trials from Embase, ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

Double-blind randomised controlled studies of add-on clonazepam in people with resistant focal or generalised onset seizures, with a minimum treatment period of eight weeks. The studies could be of parallel or cross-over design.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted relevant data, and assessed trial quality. We contacted study authors for additional information.

MAIN RESULTS

We found no double-blind randomised controlled trials which met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no evidence from double-blind randomised controlled trials for or against the use of clonazepam as an add-on therapy for adults and children with drug-resistant focal or generalised onset epileptic seizures. Since the last version of this review no new studies have been found.

Clonazepam monotherapy for treating people with newly diagnosed epilepsy

BACKGROUND

Epilepsy is one of the most common neurological disorders worldwide, with an age-adjusted prevalence of 4 to 8 per 1000 population and an age-adjusted incidence of 44 per 100,000 person-years in developed countries. Monotherapy represents the best therapeutic option in people with newly diagnosed epilepsy.

OBJECTIVES

To assess the efficacy and tolerability of oral clonazepam used as monotherapy for newly diagnosed epilepsy, when compared with placebo or a different anti-seizure medication.

SEARCH METHODS

The following databases were searched on 24 July 2018: the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) 1946 to 24 July 2018, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

We included randomized controlled trials (RCTs) or quasi-RCTs comparing oral clonazepam used as monotherapy treatment (where participants were randomized to treatment with a single drug throughout the study period) versus placebo or a different anti-seizure medication (active comparator) in people of any age with newly diagnosed epilepsy, defined according to the clinical practical definition proposed by the International League Against Epilepsy (ILAE).

DATA COLLECTION AND ANALYSIS

The following outcomes were considered: proportion of participants seizure-free at one, three, six, 12 and 24 months after randomization; proportion of responders (those with at least a 50% reduction in seizure frequency from baseline to end of treatment); proportion of participants with treatment-emergent adverse events (TEAEs) during the treatment period or leading to discontinuation during the treatment period; proportion of dropouts/withdrawals due to side effects, lack of efficacy or other reasons; and improvement in quality of life, as assessed by validated and reliable rating scales. Two review authors independently screened all titles and abstracts to assess the eligibility of publications identified by the searches. They independently extracted data from trial reports and cross-checked them for accuracy. Any disagreements between the two authors regarding data extraction were resolved by discussion and consensus. We scrutinized trials and evaluated the methodological quality of all included studies. We used GRADE assessment criteria to evaluate the certainty of the evidence.

MAIN RESULTS

Two randomized controlled trials were included, with a total of 115 participants. One study compared clonazepam to carbamazepine as monotherapy for participants with newly diagnosed psychomotor epilepsy (a condition corresponding to what is now termed mesial temporal lobe epilepsy). One study (published as abstract) compared clonazepam to ethosuximide as monotherapy for children with absence seizures. Based on the available data and the details on methodology provided, we judged both studies as being at unclear or high risk of bias for the domains assessed. In the study comparing clonazepam to carbamazepine, no difference was found between the groups regarding the proportion of participants who were seizure-free at one month after randomization (risk ratio (RR) 1.97, 95% confidence interval (CI) 0.99 to 3.94; 30 participants; very low-certainty evidence), three months after randomization (RR 1.19, 95% CI 0.62 to 2.29; 26 participants; very low-certainty evidence), and six months after randomization (RR 0.50, 95% CI 0.09 to 2.73; 9 participants; very low-certainty evidence). No statistical difference was found between clonazepam and carbamazepine in terms of proportion of participants with TEAEs leading to discontinuation (RR 2.61, 95% CI 0.80 to 8.52; 36 participants; very low-certainty evidence) and in terms of dropouts/withdrawals due to side effects, lack of efficacy or other reasons (RR 1.56, 95% CI 0.61 to 4.02; 36 participants; very low certainty evidence). The study did not provide any information on our other prespecified outcomes of interest. The study comparing clonazepam to ethosuximide did not provide any data on efficacy. The proportion of dropouts/withdrawal was higher in the group receiving clonazepam compared to the group receiving ethosuximide (RR 3.63, 95% CI 1.12 to 11.74; 79 participants; very low-certainty evidence). No information on other outcomes of interest was provided in this study.

AUTHORS' CONCLUSIONS

There is only limited and very low-certainty evidence from randomized controlled trials on the efficacy and tolerability of clonazepam used in monotherapy for the treatment of epilepsy. No difference in efficacy and tolerability was found in a small trial comparing clonazepam to carbamazepine for the treatment of mesial temporal lobe epilepsy. Clonazepam was less well tolerated than ethosuximide in a trial of children with absence seizures, however no comparative data on efficacy were provided. There is currently insufficient evidence to support the use of clonazepam as monotherapy treatment for epilepsy.

Clonazepam add-on therapy for refractory epilepsy in adults and children

BACKGROUND

Epilepsy affects about 50 million people worldwide, nearly a quarter of whom have drug-refractory epilepsy. People with drug-refractory epilepsy have increased risks of premature death, injuries, psychosocial dysfunction, and a reduced quality of life.

OBJECTIVES

To assess the efficacy and tolerability of clonazepam when used as an add-on therapy for adults and children with refractory focal onset or generalised onset epileptic seizures, when compared with placebo or another antiepileptic agent.

SEARCH METHODS

We searched the following databases on 14 September 2017: Cochrane Epilepsy Group Specialized Register, Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO), MEDLINE (Ovid 1946 to 14 September 2017), ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

Double-blind randomised controlled studies of add-on clonazepam in people with refractory focal or generalised onset seizures, with a minimum treatment period of eight weeks. The studies could be of parallel or cross-over design.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted relevant data, and assessed trial quality. We contacted study authors for additional information.

MAIN RESULTS

No double-blind randomised controlled trials met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no evidence from double-blind randomised controlled trials for or against the use of clonazepam as an add-on therapy for adults and children with refractory focal or generalised onset epileptic seizures.

Quantitative Pharmaco-Electroencephalography in Antiepileptic Drug Research

Pharmaco-electroencephalography (pharmaco-EEG) has never gained great popularity in epilepsy research. Nevertheless, the electroencephalogram (EEG) is the most important neurological examination technique in this patient population. Development and investigation of antiepileptic drugs (AEDs) involves EEG for diagnosis and outcome evaluation. In contrast to the common use of the EEG for documenting the effect of AEDs on the presence of interictal epileptiform activities or seizures, quantitative analysis of drug responses in the EEG are not yet standard in pharmacological studies. We provide an overview of dedicated pharmaco-EEG studies with AEDs in humans. A systematic search in PubMed yielded 43 articles, which were reviewed for their relevance. After excluding studies according to our exclusion criteria, nine studies remained. These studies plus the retrieved references from the bibliographies of the identified studies yielded 37 studies to be included in the review. The most prominent method in pharmaco-EEG research for AEDs was analysis of the frequency content in response to drug intake, often with quantitative methods such as spectral analysis. Despite documenting the effect of the drug on brain activity, some studies were conducted in order to document treatment response, detect neurotoxic effects, and measure reversibility of AED-induced changes. There were some attempts to predict treatment response or side effects. We suggest that pharmaco-EEG deserves more attention in AED research, specifically because the newest drugs and techniques have not yet been subject to investigation.

Should epileptiform discharges be treated?

To evaluate the impact of epileptiform discharges (EDs) that do not occur within seizure patterns--such as spikes, sharp waves or spike waves--on cognitive function and to discuss the circumstances under which treatment of EDs might be considered. Methods used in this article is "Review of the literature". EDs may disrupt short-term cognition in humans. Frequent EDs for a prolonged period can potentially impair long-term cognitive function in humans. However, there is conflicting evidence on the impact of EDs on long-term cognitive outcome because this relationship may be confounded by multiple factors such as underlying etiology, seizures, and medication effects. Limitations of existing studies include the lack of standardized ED quantification methods and of widely accepted automated spike quantification methods. Although there is no solid evidence for or against treatment of EDs, a non-evidence-based practical approach is suggested. EDs in otherwise asymptomatic individuals should not be treated because the risks of treatment probably outweigh its dubious benefits. A treatment trial for EDs may be considered when there is cognitive dysfunction or regression or neurologic symptoms that are unexplained by the underlying etiology, comorbid conditions, or seizure severity. In patients with cognitive or neurologic dysfunction with epilepsy or EDs, treatment may be warranted to control the underlying epileptic syndrome. EDs may cause cognitive or neurologic dysfunction in humans in the short term. There is conflicting evidence on the impact of EDs on long-term cognitive outcome. There is no evidence for or against treatment of asymptomatic ED.

Antiepileptic Drug Treatment in Children with Epilepsy

Most children with new-onset epilepsy achieve seizure freedom with appropriate antiepileptic drugs (AEDs). However, nearly 20 % will continue to have seizures despite AEDs, as either monotherapy or in combination. Despite the growing market of new molecules over the last 20 years, the proportion of drug-resistant epilepsies has not changed. In this review, we report the evidence of efficacy and safety based on phase III randomized controlled clinical trials (RCTs) of AEDs currently used in the paediatric population. We conducted a literature search using the PubMed database and the Cochrane Database of Systematic Reviews. We also analysed the RCTs of newer AEDs whose efficacy in adolescents and adults might suggest possible use in children. Most of the phase III trials on AEDs in children have major methodological limitations that considerably limit meaningful conclusions about comparative efficacy between old and new molecules. Since the efficacy of new drugs has only been reported versus placebo, the commonly held opinion that new and newer AEDs have a better safety profile than old ones does not appear to be supported by evidence. Despite limited solid evidence, pharmacological management has improved over the years as a consequence of increased awareness of some degree of specificity of treatment in relation to different epilepsy syndromes and attention to adverse events. Future research should be directed taking these factors, as well as the diversity of epilepsy, into consideration.

Interictal spikes: harbingers or causes of epilepsy?

Interictal spikes are brief paroxysmal electrographic discharges observed between spontaneous recurrent seizures in epileptic patients. The relationship between interictal spikes and the seizures that define acquired epilepsy has been debated for decades. Recent studies using long-term continuous electrographic recordings from the hippocampus and cortex in rats with kainate-induced epilepsy suggest that electrographic spikes, with waveforms similar to interictal spikes, precede the occurrence of the first spontaneous epileptic seizure. These data raise the possibility that spikes might serve as a surrogate marker of ongoing chronic epileptogenesis. Additionally, electrographic spikes might actually contribute to the development and maintenance of the epileptic state (i.e., the increased probability of spontaneous recurrent seizures). Correlational evidence for such a causal relationship has recently also been obtained in an in vitro model of epileptogenesis using organotypic hippocampal slices. Testing for a causal relationship will ultimately require selective anti-spike medications. Although no such agents currently exist, this new preparation is amenable to moderate-throughput screening, which should accelerate their discovery. Anti-spike agents may also be of benefit in ameliorating the cognitive dysfunctions associated with epilepsy, to which spike activity may contribute.

Interictal spikes and epileptogenesis

Interictal spikes are widely accepted diagnostically as a sign of epilepsy, but reasons for the presence of interictal activity in the epileptic brain are unknown. Interictal spikes are easily generated in normal brain by pharmacologically reducing inhibition, and experimental studies of acquired epilepsy indicate that spikes precede seizures. These data lead to the hypothesis that interictal spikes are correlated with epilepsy because they play a fundamental role in epileptogenesis following brain injury. Spikes may guide sprouting axons back to their network of origin, increase and sustain the strength of the synapses formed by sprouted axons, and alter the balance of ion channels in the epileptic focus, such that seizures become possible. This hypothesis has implications that are testable: altering spiking or the calcium signals generated by spikes should alter epileptogenesis and spikes should precede seizures in brain-injured human patients.

Long term effects on epileptiform activity with vagus nerve stimulation in children

PURPOSE

We report long-term effects of vagus nerve stimulation (VNS) on epileptiform activity in 15 children, and how these changes are related to activity stage and to clinical effects on seizure reduction, seizure severity (NHS3) and quality of life (QOL).

METHODS

Initially, and after 3 and 9 months of VNS-treatment, 15 children were investigated with 24 h ambulatory EEG monitoring for spike detection. The number of interictal epileptiform discharges (IEDs) and the inter spike intervals (ISIs) were analysed during 2 h in the awake state, and 1h of rapid eye movement (REM)-, spindle- and delta-sleep, respectively. Total number and duration of electrographic seizure episodes were also analysed.

RESULTS

At 9 months the total number of IEDs was significantly reduced (p=0.04). There was a tendency of reduction in all activity stages, and significantly so in delta-sleep (p=0.008). Total electrographic seizure number was significantly reduced in the 24 h EEG at 3 and 9 months (p=0.03, 0.05). There was a significant concordance in direction of changes in epileptiform activity and electrographic seizures at 9 months (p=0.04). Concordance in direction of changes was seen in 9 of 15 children between clinical seizures and IED (p>0.3), in 10 of 15 children between QOL and IED (p=0.3) and in 8 of 15 children between NHS3 and IED (p>0.3). There was no direct correlation between the extent of improvement in these clinical data and the degree of spike reduction.

CONCLUSION

This study shows that VNS reduces IEDs especially in REM and delta sleep, as well as the number of electrographic seizures. It also shows a concordance between reduction in IEDs and electrographic seizures.

Distúrbio cognitivo transitório associado a atividade epileptiforme generalizada ou difusa durante o eletrencefalograma

Atividade epileptiforme (AE) no eletrencefalograma (EEG) é achado comum entre as crises epilépticas e, menos freqüentemente, em outras condições clínicas. AE "subclínica" pode estar acompanhada de distúrbio cognitivo transitório (DCT). Foram estudados 30 pacientes (27 com epilepsia) com AE generalizada ou difusa, freqüente, em EEG inicial. Em EEG subseqüente, foi avaliado o desempenho em testes de classificação visual de animais e objetos, discriminação de cores, memória verbal e auditiva, reconhecimento de padrões e estimação de tempo. Foi comparado, estatisticamente, o número de respostas corretas ou incorretas durante a AE e fora dela. DCT foi caracterizado em 43,3% dos casos. Em 23,3% a AE foi rara, não permitindo avaliação de DCT. Assim, pôde ser caracterizado comprometimento transitório de atividades cognitivas durante AE até então considerada "subclínica". Há necessidade de pesquisar a importância desse fator em pacientes com comprometimento cognitivo e de caracterizar as situações de eventuais benefícios na medicação dirigida à AE.

Magnetoencephalographic analysis of rolandic discharges in a patient with rolandic epilepsy associated with oromotor deficits

The purpose of this study was to clarify the neurophysiologic basis of oromotor deficits in a patient with atypical rolandic epilepsy. We investigated magnetoencephalographic analysis of rolandic discharges with right predominance before and during clonazepam therapy. Before clonazepam administration, current sources of rolandic discharges were broadly distributed in the secondary sensory cortex, superior temporal gyrus, and parietal association area in addition to hand and orofacial division of the primary somatosensory cortex. During clonazepam therapy, oromotor deficits were improved, along with a decrease in rolandic discharge, and current sources of residual right-sided rolandic discharges were shifted to the right superior parietal lobule. Taking the clinical course and magnetoencephalographic findings together, the distributed rolandic discharge focus might be closely related to oromotor deficits, and clonazepam was effective for the disorder.

Treatment of spontaneous and chemically induced EEG paroxysms in the Fischer-344 rat with traditional antiepileptic drugs or AED+CGP 35348 polytherapy

Twenty-four Fischer-344 rats implanted with cortical electroencephalograph (EEG) electrodes were evaluated for frequency, duration, and mean duration (duration/frequency) of both spontaneous and chemically induced spike-and-wave discharges (SWDs) during earlier and later adulthood. Fischer-344 rats, exhibiting a low level of spontaneous SWDs during earlier adulthood, progressed to exhibit a significantly larger number and duration of SWDs during later adulthood. The convulsant trimethylolpropane phosphate (TMPP), known to antagonize the GABAA inhibitory system through blockade of the chloride channel, induced or increased SWDs in every rat tested. Spontaneous or chemically induced SWDs in Fischer-344 rats were eliminated or reduced by several drugs used to control human absence seizures. The gamma-aminobutyric acid (GABA)B antagonist CGP 35348 reduced spontaneous EEG paroxysms; CGP 35348 as a polytherapy with several traditional antiabsence treatments improved control of TMPP-induced seizures. It would appear that the Fischer-344 rat provides an excellent research alternative to use of genetically selected rodent strains for investigation of progression of absencelike epilepsy with aging, induction of SWDs by toxicant exposures, and treatment of spontaneous and chemically induced paroxysms.

Reduction of seizures with low-dose clonazepam in children with epilepsy

The acute effects of low-dose clonazepam on seizure frequency in children with epilepsy was evaluated. In an open study, 19 children with epilepsy (15 generalized and four partial) were examined during hospitalization with recordings of seizures by trained personnel. Seizures were counted during two 24-hour periods: before and after a single intramuscular injection of clonazepam 0.01-0.04 mg/kg body weight. Plasma concentrations of clonazepam were determined. The median number of seizures in all children on control days was 22 (range = 1-180) and, on days after low-dose clonazepam, the median was 6 (range = 0-73). The relative changes demonstrated a median of -70% (range from -100% to + 43%). A significant reduction of seizures (P = 0.0031) at median maximal plasma levels of clonazepam of 23 nmol/L (range = 11-41 nmol/L) was found. Thus in this study of the acute effects of a low-dose level of clonazepam on seizure frequency a significant reduction was found at plasma levels below those usually recommended. Inhibition of seizure activity seems to be achieved already at low plasma levels of clonazepam. These results suggest to start treatment at low doses of clonazepam and evaluate the individual effect carefully during dose escalation aiming at lowest possible dose with therapeutic effect.