Comparison between one and three years of treatment in uncomplicated childhood epilepsy: a prospective study. I. Outcome in different seizure types

Rapid versus slow withdrawal of antiepileptic drugs

BACKGROUND

The ideal objective of treating a person with epilepsy is to induce remission (free of seizures for some time) using antiepileptic drugs (AEDs) and withdraw the AEDs without causing seizure recurrence. Prolonged usage of AEDs may have long-term adverse effects. Hence, when a person with epilepsy is in remission, it is logical to attempt to discontinue the medication. The timing of withdrawal and the mode of withdrawal arise while contemplating withdrawal of AEDs. This review examines the evidence for the rate of withdrawal of AEDs (whether rapid or slow tapering) and its effect on seizure recurrence. This is an updated version of the Cochrane Review previously published in 2020.

OBJECTIVES

To quantify risk of seizure recurrence after rapid (tapering period of three months or less) or slow (tapering period of more than three months) discontinuation of antiepileptic drugs in adults and children with epilepsy who are in remission, and to assess which variables modify the risk of seizure recurrence.

SEARCH METHODS

For the latest update, on 8 November 2021, we searched: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid), and SCOPUS. There were no language restrictions. CRS Web includes randomized or quasi-randomized, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), CENTRAL, and the Specialized Registers of Cochrane Review Groups including Epilepsy.

SELECTION CRITERIA

Randomized controlled trials that evaluated withdrawal of AEDs in a rapid or slow tapering after varying periods of seizure control in people with epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials for inclusion and extracted the data. The outcomes assessed included seizure freedom after one, two, or five years of AED withdrawal; time to recurrence of seizure following withdrawal; occurrence of status epilepticus; mortality; morbidity due to seizure, such as injuries, fractures, and aspiration pneumonia; and quality of life (assessed by validated scale).

MAIN RESULTS

There are two included studies in this review. One study randomized 57 children with epilepsy with seizure freedom for at least two years to taper down the AED over one or six months. The study was not blinded and there were no details of randomization. Over the period of 54 months of follow-up, 20/30 participants in the one-month group remained seizure-free compared to 15/27 participants in the six-month group (no evidence of a difference). There was no information on time of seizure recurrence for each group to allow a comparison. The other study involved 149 children. There was a non-significant trend towards a lower risk of seizure recurrence after one year of AED withdrawal in participants allocated to slow tapering (risk ratio (RR) 0.76, 95% confidence interval (CI) 0.58 to 1.01; P = 0.06; very low-certainty evidence). At the end of two years, 30 participants were seizure free in the rapid-tapering group and 29 participants in the slow-tapering group (RR 0.87, 95% CI 0.58 to 1.29; P = 0.48; very low-certainty evidence). At the end of five years, 10 participants were seizure free in the rapid-tapering group and six participants in the slow-tapering group (RR 1.40, 95% CI 0.54 to 3.65; P = 0.49; very low-certainty evidence). There were no data for the other outcomes. Due to the methodological heterogeneity and the difference in the duration of tapering, we did not perform a quantitative synthesis of these studies. Currently, one Italian trial is ongoing that is investigating if a slow or a rapid withdrawal schedule of AEDs influences return of seizures (relapse) in adults with focal or generalized epilepsy who have been seizure free for at least two years (no preliminary results available).

AUTHORS' CONCLUSIONS

In view of methodological deficiencies, and small sample size of the two included studies, we cannot draw any reliable conclusions regarding the optimal rate of tapering of AEDs. Using GRADE, we assessed the certainty of the evidence as very low for outcomes for which data were available. We judged both studies to be at an overall high risk of bias. Further studies are needed in adults and children to investigate the optimal rate of withdrawal of AEDs and to study the effects of variables such as seizure types, aetiology, intellectual disability, electroencephalography abnormalities, presence of neurological deficits, and other comorbidities on the rate of tapering.

Antiseizure Medication Withdrawal in Seizure-Free Patients: Practice Advisory Update Summary: Report of the AAN Guideline Subcommittee

OBJECTIVE

To update a 1996 American Academy of Neurology practice parameter.

METHODS

The authors systematically reviewed literature published from January 1991 to March 2020.

RESULTS

The long-term (24-60 months) risk of seizure recurrence is possibly higher among adults who have been seizure-free for 2 years and taper antiseizure medications (ASMs) vs those who do not taper ASMs (15% vs 7% per the 1 Class I article addressing this issue). In pediatric patients, there is probably no significant difference in seizure recurrence between those who begin tapering ASMs after 2 years vs 4 years of seizure freedom, and there is insufficient evidence of significant difference in risk of seizure recurrence between those who taper ASMs after 18 months of seizure freedom and those tapering after 24 months. There is insufficient evidence that the rate of seizure recurrence with ASM withdrawal following epilepsy surgery after 1 year of seizure freedom vs after 4 years is not significantly different than maintaining patients on ASMs. An epileptiform EEG in pediatric patients increases the risk of seizure recurrence. ASM withdrawal possibly does not increase the risk of status epilepticus in adults. In seizure-free adults, ASM weaning possibly does not change quality of life. Withdrawal of ASMs at 25% every 10 days to 2 weeks is probably not significantly different from withdrawal at 25% every 2 months in children who are seizure-free in more than 4 years of follow-up.

RECOMMENDATIONS

Fourteen recommendations were developed.

Long-term seizure and psychosocial outcome in childhood epilepsy of unknown cause

OBJECTIVE

The purpose was to investigate long-term prognosis of epilepsy of unknown cause with onset between ages 2 and 16 in children without any major disability, by evaluation of a previously described prognostic model and long-term follow-up of a study on the impact of duration of initial antiseizure medication (ASM) treatment.

METHODS

Patients included in a randomized controlled trial (RCT) of either one or three years of ASM therapy prior to withdrawal (if seizure-free for at least 6 months) were contacted after 29-35 years and asked to complete a survey. Potential prognostic factors were evaluated: duration of initial ASM treatment, seizure type, seizure frequency, and score in a prognostic model developed in the initial publication.

RESULTS

One hundred and forty-nine subjects answered the questionnaire (response rate 65%). Seizure freedom without treatment was found in 110 responders (77%, 95%CI: 73-81). There was no significant difference in score in the prognostic model between responders with and without epilepsy at follow-up. Those with active epilepsy were unemployed significantly more often and perceived their mental health significantly more affected than those seizure-free without treatment.

CONCLUSIONS

Duration of initial ASM treatment was not associated with any difference in subsequent epilepsy risk. This indicates that the timing of withdrawal attempts is unlikely to alter the long-term prognosis of uncomplicated childhood epilepsy. The failure of the prognostic model from the initial study to predict long-term outcome argues that although prediction of relapse risk in the shorter term may be possible, the bearing of such models on long-term epilepsy risk is more questionable.

Rapid versus slow withdrawal of antiepileptic drugs

BACKGROUND

The ideal objective of treating a person with epilepsy is to induce remission (free of seizures for some time) using antiepileptic drugs (AEDs) and withdraw the AEDs without causing seizure recurrence. Prolonged usage of AEDs may have long-term adverse effects. Hence, when a person with epilepsy is in remission, it is logical to attempt to discontinue the medication. The timing of withdrawal and the mode of withdrawal arise while contemplating withdrawal of AEDs. This review examines the evidence for the rate of withdrawal of AEDs (whether rapid or slow tapering) and its effect on seizure recurrence. This is an updated version of the original Cochrane Review published in 2006, Issue 2.

OBJECTIVES

To quantify risk of seizure recurrence after rapid (tapering period of three months or less) or slow (tapering period of more than three months) discontinuation of antiepileptic drugs in adults and children with epilepsy who are in remission, and to assess which variables modify the risk of seizure recurrence.

SEARCH METHODS

For the latest update, on 9 April 2019, we searched: Cochrane Register of Studies (CRS Web, which includes the Cochrane Epilepsy Group Specialized Register, CENTRAL, and ClinicalTrials.gov), MEDLINE (Ovid; 8 April 2019), the WHO International Clinical Trials Registry Platform, and SCOPUS. There were no language restrictions.

SELECTION CRITERIA

Randomized controlled trials that evaluate withdrawal of AEDs in a rapid or slow tapering after varying periods of seizure control in people with epilepsy.

DATA COLLECTION AND ANALYSIS

Review authors independently assessed the trials for inclusion and extracted the data. The outcomes assessed included seizure freedom after one, two, or five years of AED withdrawal; time to recurrence of seizure following withdrawal; occurrence of status epilepticus; mortality; morbidity due to seizure, such as injuries, fractures, and aspiration pneumonia; and quality of life (assessed by validated scale).

MAIN RESULTS

In this review update, we have included one new study. The new study randomized 57 children with epilepsy with seizure freedom for at least two years to taper the AED during over one or six months. The study was not blinded and there were no details of randomization. Over the period of 54 months of follow-up, 20/30 participants in the one-month group remained seizure-free compared to 15/27 participants in the six-month group (no evidence of a difference). There was no information on time of seizure recurrence for each group to allow a comparison. One trial had already been included in the previous version of the review; it involved 149 children. There was a non-significant trend toward a lower risk of seizure recurrence after one year of AED withdrawal in participants allocated to slow tapering (risk ratio (RR) 0.76, 95% confidence interval (CI) 0.58 to 1.01; P= 0.06; very low-certainty evidence). At the end of two years, 30 participants were seizure free in the rapid-tapering group and 29 participants in the slow-tapering group (RR 0.87, 95% CI 0.58 to 1.29; P = 0.48; very low-certainty evidence). At the end of five years, 10 participants were seizure free in the rapid-tapering group and six participants in the slow-tapering group (RR 1.40, 95% CI 0.54 to 3.65; P = 0.49; very low-certainty evidence). There were no data for the other outcomes. Due to the methodological heterogeneity and the difference in the duration of tapering we did not perform a quantitative synthesis of these studies.

AUTHORS' CONCLUSIONS

Since the last version of this review was published, we found one new pediatric study. In view of methodological deficiencies, and small sample size of the two included studies, we cannot draw any reliable conclusions regarding the optimal rate of tapering of AEDs. Using GRADE, we assessed the certainty of the evidence as very low for outcomes for which data were available. We judged both studies to be at high risk of bias. Further studies are needed in adults and children to investigate the optimal rate of withdrawal of AEDs and to study the effects of variables such as seizure types, etiology, mental retardation, electroencephalography abnormalities, presence of neurologic deficits, and other comorbidities on the rate of tapering.

Relative Seizure Relapse Risks Associated with Antiepileptic Drug Withdrawal After Different Seizure-Free Periods in Adults with Focal Epilepsy: A Prospective, Controlled Follow-Up Study

BACKGROUND

Approximately two-thirds of patients with newly diagnosed epilepsy become seizure-free after antiepileptic drug (AED) treatment. A crucial issue for these patients and their families, especially after a long period of seizure freedom, is when to stop their medications.

OBJECTIVE

The aim of this study was to identify the optimal timing of AED withdrawal in adults with focal epilepsy who had been seizure-free for ≥ 2 years.

METHODS

Adults with focal epilepsy who had been seizure-free for ≥ 2 years were recruited. Based on their decision to discontinue (withdrawal) or continue (non-withdrawal) AED treatment, patients were assigned to withdrawal or non-withdrawal subgroups according to the length of remission (2 to < 3 years, 3 to < 4 years, 4 to < 5 years and ≥ 5 years). The relapse risks of the withdrawal and corresponding non-withdrawal subgroups were compared, and the relative relapse risks were assessed in a Cox proportional hazard regression model.

RESULTS

A total of 213 eligible patients began to withdraw from AED treatment; 70 had been seizure-free for 2 to < 3 years, 62 had been seizure-free for 3 to < 4 years, 37 had been seizure-free for 4 to < 5 years and 44 had been seizure-free for ≥ 5 years. The figures for the corresponding non-withdrawal subgroups were 463, 334, 251 and 182, respectively. There was a significantly higher risk of seizure relapse in patients withdrawing from AEDs after 2 to < 5 years of seizure freedom than in the corresponding non-withdrawal controls, and the relative relapse risk was 3.052 (95% confidence interval [CI] 2.126-4.381; p < 0.001) for the seizure-free period of 2 to < 3 years, 3.617 (95% CI 2.384-5.488; p < 0.001) for 3 to < 4 years and 2.644 (95% CI 1.456-4.799; p = 0.001) for 4 to < 5 years. However, for patients who were seizure-free for ≥ 5 years, AED withdrawal did not significantly increase the risk of seizure relapse compared with that of patients continuing treatment (hazard ratio [HR] 1.362, 95% CI 0.634-2.926, p = 0.428). Compared with a seizure-free period of 2 to < 3 years, the relative relapse risk after AED withdrawal was significantly reduced only after being seizure-free for ≥ 5 years (HR 0.441, 95% CI 0.233-0.834; p = 0.012).

CONCLUSION

Overall, for adults with focal epilepsy, withdrawal from AEDs significantly increased the risk of seizure relapse after being seizure-free for 2 to < 5 years, but might not increase the risk if the seizure-free period was ≥ 5 years.

Antiepileptic Drugs in Children : Current Concept

An epileptic seizure is defined as the transient occurrence of signs and/or symptoms due to abnormally excessive or synchronous neuronal activity in the brain. The type of seizure is defined by the mode of onset and termination, clinical manifestation, and by the abnormal enhanced synchrony. If seizures recur, that state is defined as epilepsy. Antiepileptic drugs (AEDs) are the mainstay of treatment. Knowledge about initiating and maintaining adequate AEDs is beneficial for the clinician who treats children with epilepsy. This article will delineate the general principles for selecting, introducing, and discontinuing AEDs and outline guidelines for monitoring adverse effects. In general, AED therapy following a first unprovoked seizure in children is not recommended. However, treatment should be considered after a second seizure. In children and adolescents, if they are seizure-free for at least 2 years, attempts to withdraw medication/s should be made, taking into account the risks vs. benefits for the individual patient. The decision on when and what AED to use should be tailored according to the patient. For optimal treatment, the selection of adequate AEDs can be achieved by considering the precise definition of the patient’s seizure and epilepsy syndrome. Continuous monitoring of both therapeutic and adverse effects is critical for successful treatment with AEDs.

Uncertainties from a worldwide survey on antiepileptic drug withdrawal after seizure remission

Background

We sought to determine differences in practice for discontinuation of antiepileptic drugs (AEDs) after seizure remission and stimulate the planning and conduction of withdrawal trials.

Methods

We utilized a worldwide electronic survey that included questions about AED discontinuation for 3 paradigmatic cases in remission: (1) focal epilepsy of unknown etiology, (2) temporal lobe epilepsy after surgery, and (3) juvenile myoclonic epilepsy. We analyzed 466 complete questionnaires from 53 countries, including the United States. Statistical analysis included χ² and multivariate logistic regression.

Results

Case 1: responders in practice for <10 years were less likely to taper AEDs: odds ratio (OR) (95% confidence interval [CI]) 0.52 (0.32-0.85), p = 0.02. The likelihood of stopping AEDs was higher among doctors treating children: OR (95% CI): 11.41 (2.51-40.13), p = 0.002. Doctors treating children were also more likely to stop after 2 years or less of remission: OR (95% CI): 6.91 (2.62-19.31), p = 0.002, and the same was observed for US physicians: OR (95% CI): 1.61 (1.01-2.57), p = 0.0049. Case 2: responders treating children were more likely to taper after 1 year or less of postoperative remission, with the goal of discontinuing all medications: OR (95% CI): 1.91 (1.09-3.12), p = 0.015, and so were US-based responders: OR (95% CI): 1.73 (1.21-2.41), p = 0.003. Case 3: epileptologists were less likely to withdraw the medication: OR (95% CI): 0.56 (0.39-0.82), p = 0.003, and so were those in practice for 10 or more years: OR (95% CI): 0.54 (0.31-0.95), p = 0.025.

Conclusions

We observed several differences in practice for AED withdrawal after seizure remission that highlight global uncertainty. Trials of AED discontinuation are needed to provide evidence-based guidance.

Early versus late antiepileptic drug withdrawal for people with epilepsy in remission

BACKGROUND

Epilepsy is a chronic neurological disorder which affects millions of people around the world. Antiepileptic drugs (AED) are the main interventions used to prevent seizures and control epilepsy. Although effective in most cases, AEDs are related to long-term adverse effects, such as cognitive and behavioural alterations. Thus when epilepsy is in remission, it may be in the individual's best interest to discontinue medication. However, the optimal timing of AED discontinuation is still unknown.This is an updated version of the original Cochrane review published in Issue 3, 2001.

OBJECTIVES

(1) To quantify and compare risk of seizure recurrence, status epilepticus and mortality after early and late AED discontinuation in adult and pediatric epilepsy patients.(2) To assess which variables modify the risk of seizure recurrence.(3) To define a subpopulation in which early AED discontinuation is safe.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (June 2014); CENTRAL (Issue 5, The Cochrane Library, May 2014); MEDLINE (1946 to June 2014); CINAHL (23 June 2014); Scopus (1823 to June 2014); ClinicalTrials.gov (23 June 2014); and WHO International Clinical Trials Registry Platform (23 June 2014). We also checked the reference lists of studies found through the electronic searches.

SELECTION CRITERIA

Randomised controlled trials that evaluate withdrawal of AEDs after varying periods of seizure remission in adults and children with epilepsy. Included studies compared an early AED discontinuation time (defined as a period of remission of seizures of less than two years) versus a late AED discontinuation time (defined as a period of remission of seizures of more than two years).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. Risk ratio (RR) with 95% confidence interval (CI) was calculated for each trial. Summary RRs and 95% CIs for dichotomous data were calculated using a fixed-effect model. A test of statistical heterogeneity was conducted for each pooled risk ratio calculation. Each included study underwent a 'Risk of bias' assessment, based on the Cochrane Handbook recommendations, and we examined the overall quality of information through the GRADE system, presented in two 'Summary of Findings' tables.

MAIN RESULTS

Five trials were included in this review, representing 924 randomised children with epilepsy, all under 16 years of age at randomisation, with a median follow-up of 5.6 years. No eligible trial evaluated adults or assessed mortality or status epilepticus as outcomes. The pooled risk ratio for seizure relapse after AED withdrawal was 1.34 (95% CI 1.13 to 1.59, P = 0.0007). Conforming to this estimate, the number needed to harm, that is expose an individual to a higher risk of seizure relapse because of early withdrawal of AED, is 8 (95% CI 5 to 20). Early discontinuation was associated with greater relapse rates in people with partial seizures with a pooled risk ratio of 1.51 (95% CI 0.97 to 2.35, P = 0.07). Absence type epilepsy showed a lower risk of relapse. Variables associated with higher risk of seizure relapse were abnormal EEG findings (pooled RR 1.44, 95% CI 1.13 to 1.83, P = 0.003), especially epileptiform activity (RR 2.58, 95% CI 2.03 to 3.28, P < 0.0001); epilepsy onset before 2 years or after 10 years of age; history of status epilepticus; intellectual disability (IQ < 70); and high seizure frequency before and during treatment. Gender and family history did not show any significant influence over seizure relapse. Overall, the included trials were classified as low or unclear risk of bias where methodological information was not reported and could not be provided by original study authors.

AUTHORS' CONCLUSIONS

There is evidence to support waiting for at least two seizure-free years before discontinuing AEDs in children, particularly if individuals have an abnormal EEG or partial seizures, or both. There is insufficient evidence to establish when to withdraw AEDs in children with generalised seizures. There is no evidence to guide the timing of withdrawal of AEDs in seizure-free adults. Further high-quality randomised controlled trials are needed, particularly recruiting adults and recruiting those with generalised seizure types, to identify the optimal timing of AED withdrawal and risk factors predictive of relapse.

Benign epilepsy of childhood with centrotemporal spikes (BECTS): to treat or not to treat, that is the question

The goal of this review is to assess the value of treating versus not treating benign epilepsy (of childhood) with centrotemporal spikes (BECTS). Among 110 recommendations from 96 articles, two-thirds generally favored and one-third generally did not favor treatment with antiepileptic drugs (AEDs). Two studies concluded that all patients should be treated, but most investigators added qualifications, for example, treating those with early onset, multiple seizures at onset, and large numbers of seizures, especially generalized tonic-clonic seizures, and limiting treatment to 1 year. Other studies made treatment dependent on epileptiform discharges or amelioration of symptoms. Specific AEDs were reviewed, and in the largest number of positive studies, valproic acid or carbamazepine was favored. Among the studies generally opposing treatment, none opposed treatment for all patients in all circumstances. Usually, qualifications to treat were added, for example, if generalized tonic-clonic seizures occurred or if there was a change in quality of life. One AED associated with negative effects was carbamazepine, treatment with which can result in the development of epileptic negative myoclonus, absence seizures, and generalized spike-wave complexes on the EEG. Thus, if treatment is planned, valproic acid may be considered the drug of choice in BECTS. Although many neurologists oppose treatment; twice as many studies concluded in favor of treatment. The typical benign aspect of this disorder may allow for nontreatment to be without serious consequences.

Polyspike and waves do not predict generalized tonic-clonic seizures in childhood absence epilepsy

About 40% of children with childhood absence epilepsy develop generalized tonic-clonic seizures. It is commonly held that polyspike-wave pattern on the electroencephalogram (EEG) can predict this development of generalized tonic-clonic seizures. However, there is no firm evidence in support of this proposition. To test this assumption, we used survival analysis and compared the incidence of generalized tonic-clonic seizures in 115 patients with childhood absence epilepsy having either isolated 3-Hz spike-wave or coexisting 3 Hz and polyspike-waves and other variables. There was no evidence that polyspike-waves predicted development of generalized tonic-clonic seizures in patients with childhood absence epilepsy. Later age of onset (> or =8 years) and family histories of generalized tonic-clonic seizures were the only independent predictors. These results have implications for counseling and in the choice of first-line antiepileptic drugs used for childhood absence epilepsy, especially if valproate is chosen based on the observation of polyspike-waves.

When to start drug treatment for childhood epilepsy: the clinical-epidemiological evidence

INTRODUCTION

Many data on the course and prognosis after provoked and unprovoked single and multiple seizures in childhood have been collected in the past decennia by prospective, large-scale, long-term observational cohort studies. These data may serve to guide treatment decisions and help to design controlled trials investigating treatment strategies in childhood epilepsy.

METHODS

The results of the Dutch study of epilepsy in childhood will be compared with those of other studies. We will also discuss the potential consequences of these results for the "why" and "when" of the decision to start treatment.

RESULTS

Recurrence after a solitary unprovoked seizure in childhood is about 50%. Those with a recurrence have a similar outcome of their epilepsy compared to children presenting with multiple seizures, regardless whether they were treated after the first seizure or not. This argues in favour of postponing anti-epileptic drug (AED) treatment until at least a second seizure has occurred. After an unprovoked status epilepticus (SE), later outcome is not worse than after presentation with a short seizure. Therefore, long-term AED treatment after a single unprovoked SE may not be necessary either. The same holds true for children presenting with a short (less than one week) burst of unprovoked seizures. One quarter of them do not have recurrences and the final prognosis of children with recurrences does again not differ from the prognosis of the entire cohort. Findings in new-onset epilepsy further indicate that AED treatment can be safely omitted or at least postponed in about 15%, especially those with only a small number of seizures before presentation, those with benign partial epilepsy and those with sporadic generalised tonic-clonic seizures. On the reverse side, three considerations might lead to the decision to start early and aggressive treatment: the dangers of the seizures, the chance of intractability and the possibility of intellectual decline caused by recurrent seizures or epileptic activity. In idiopathic generalised absence epilepsy, the risks of accidents and learning problems indeed prompt early AED treatment. A self-propagating mechanism of seizures promoting the occurrence of more seizures, in the end causing intractable epilepsy (Gowers), occurs only rarely. Real intractability is seen in only 5-15% of the children with new-onset epilepsy. The chance of intractability is increased by variables like symptomatic aetiology, localisation-related epilepsy, and an early unfavourable course. Landau-Kleffner or continuous spikes and waves during sleep (CSWS) syndrome cause cognitive decline and syndromes like West, Lennox-Gastaut or Dravet's induce both psychomotor regression and intractability. In such cases, early aggressive treatment is indicated, including early consideration of the ketogenic diet, immunotherapy, vagus nerve stimulation and, if possible, referral for epilepsy surgery.

CONCLUSIONS

Omitting or postponing treatment after a solitary seizure, an unprovoked SE, a single burst of seizures or multiple infrequent seizures usually does not worsen the prognosis. A poor prognosis and the consequent indication for early and aggressive treatment are dependent mainly upon the presence of variables like symptomatic aetiology, certain epilepsy types and syndromes, and the early evolution of the epilepsy in that particular child. Intellectual decline caused by seizures or epilepsy is rare and may be confined to certain specific and readily recognizable syndromes.

The office management of epilepsy

Epilepsy in children is mostly diagnosed and treated in an ambulatory office setting. This article reviews the literature and offers opinions about the best practice from the time of diagnosis through to remission and beyond. The diagnosis and assignment of an epilepsy syndrome may be difficult, and even experts disagree in many cases. Regular review of the basic diagnosis and semiology of seizures is suggested throughout treatment. Workup should always include an electroencephalogram and usually magnetic resonance imaging. Antiepileptic drugs (AEDs) suppress seizures but appear to have little effect on long-term remission, and the choice of AED is for the most part arbitrary with most AEDs having a similar success rate when used as the first drug. Families have a great need for accurate information, and their ability to cope with the unpredictable nature of seizures may be assisted by "rescue" home benzodiazepines. Surveillance for drug toxicity and side effects is a critical clinical skill that is not assisted by routine blood tests or AED serum levels. Most children with epilepsy do not have many seizures and need not have significant restrictions on their activities. In the long run, comorbidities (especially learning and behavior problems) have a greater impact on social function than the epilepsy. Management of these problems may extend well beyond remission of the epilepsy. The child neurologist needs to prepare children with persistent epilepsy for transfer to adult epilepsy services.

Rapid versus slow withdrawal of antiepileptic drugs

BACKGROUND

The ideal objective of treating a person with epilepsy is to induce remission by usage of antiepileptic drugs (AEDs) and withdraw the AEDs without causing seizure recurrence. Prolonged usage of AEDs may have long-term side effects. Hence when a person with epilepsy is in remission (free of seizures for some time) it is logical to attempt to discontinue the medication. The timing of withdrawal and the mode of withdrawal arise while contemplating withdrawal of AEDs. This review proposes to examine the evidence for the rate of withdrawal of AEDs (whether rapid or slow tapering) and its effect on recurrence of seizure. This review also examines the effect of variables such as age of seizure onset, seizure types, presence of neurological deficits, mental subnormality, aetiology of epilepsy, type of AED, EEG findings or duration of seizure freedom on the risk of recurrence of seizures with the two tapering regimens.

OBJECTIVES

(1) To quantify risk of seizure recurrence after rapid (taper period of three months or less) or slow (taper period or more than three months) discontinuation of antiepileptic drugs in adults with epilepsy who are in remission. (2) To quantify the risk of seizure recurrence after rapid (taper period of three months or less) or slow (taper period of more than three months) discontinuation of antiepileptic drugs in children with epilepsy who are in remission. (3) To attempt to assess which variables modify the risk of seizure recurrence.

SEARCH STRATEGY

We searched the Cochrane Epilepsy Group's Specialized Register (August 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to September 2004) and cross-references from identified studies. No language restrictions were imposed.

SELECTION CRITERIA

Randomized controlled trials that evaluate withdrawal of AEDs in a rapid or slow manner after varying periods of seizure control in patients with epilepsy.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed the trials for inclusion and extracted the data. The outcomes assessed included seizure relapse (i.e. the percentage of patients experiencing seizure recurrence after withdrawal of AED); time to recurrence of seizure following withdrawal; occurrence of status epilepticus; mortality; morbidity due to seizure such as injuries, fractures, aspiration pneumonia; and quality of life (if assessed by validated scale).

MAIN RESULTS

One trial with weak methodology involving 149 children was included with a mean age of seizure onset of four years, mean age of 11 years at the time of starting the taper. The rapid taper group (six weeks) recruited 81 participants and the slow taper group (nine months) included 68 participants, out of whom 11 and 5 were lost to follow up even before the taper began respectively. The number of participants who were seizure free in the rapid and slow taper groups were 40 and 44 respectively at the end of one year follow up (OR 0.53, 95% CI 0.27 to 1.03); 30 and 29 respectively at the end of two years, (OR 0.79, 95% CI 0.41 to 1.53); 24 and 14 respectively at the end of three years (OR 1.62, 95% CI 0.76 to 3.46); 18 and 8 respectively at the end of four years (OR 2.14, 95% CI 0.87 to 5.3); 10 and 6 respectively at the end of five years (OR 1.46, 95% CI 0.5 to 4.23).

AUTHORS' CONCLUSIONS

In view of methodological deficiencies and small sample size, in the solitary study identified, we cannot derive any reliable conclusions regarding the optimal rate of tapering of AEDs. Further studies are needed in adults as well as in children to investigate the rate of withdrawal of AEDs and to study the effects of variables such as seizure types, its aetiology, mental retardation, EEG abnormalities, presence of neurological deficits and other co-morbidities on the rate of tapering.

Prognosis after withdrawal of antiepileptic drugs in childhood-onset cryptogenic localization-related epilepsies

The purpose of this study was to clarify the risk factors of relapse following discontinuation of AEDs in patients with childhood-onset cryptogenic localization-related epilepsies. The subjects were 82 patients who fulfilled the following criteria: (1) age at first visit of less than 15 years, (2) follow-up period of more than 5 years, (3) suffering from cryptogenic localization-related epilepsies, and (4) the patient underwent AED withdrawal during the follow-up period. As a basic principle, we decided to start withdrawing AEDs when both of the following two conditions were met: (1) the patient had a seizure-free period of 3 years or more, and (2) there were no epileptic discharges on EEGs just prior to the start of withdrawal. Seizures recurred in eight of the 82 patients (9.8%). Univariate analysis revealed that the following factors were correlated with higher rates of seizure relapse: 6 years of age or higher at onset of epilepsy; 15 years of age or higher at the start of AED withdrawal; 5 years or more from the start of AED treatment to seizure control; five or more seizures before seizure control; and two or more AEDs administered before seizure control. Among these risk factors, 6 years of age or higher at onset and 5 years or more from the start of AED treatment to seizure control were determined by multivariate analysis to be independent risk factors for relapse. Thus, we conclude that the physician should be more careful in discontinuing AEDs in these higher-risk patients groups, and more generous in discontinuing AEDs in lower-risk groups.

Childhood epilepsy: what is the evidence for what we think and what we do?

This article reviews the strength of the evidence that underlies the current approach to the management of childhood epilepsy. The authors reviewed published, peer-reviewed English literature accessed through PubMed and Cochrane reviews with evidence rated as Class 1 (strongest) to Class 4 (weakest). There is considerable inaccuracy in the diagnosis of seizures and epilepsy syndromes. Sound information supports the consensus that the diagnosis of epilepsy should await two unprovoked seizures. Population-based studies indicate that remission from childhood onset epilepsy occurs in at least 50% of children. It is easier to predict a good seizure outcome than a poor one. Absence of concomitant neurologic handicap and onset before about 12 years of age are the most consistent predictors of remission. Intractability is poorly defined and difficult to predict until several antiepilepsy drugs have been used and failed to control the seizures. Most epilepsy syndrome diagnoses do not yield an accurate prognosis. Social outcome appears unsatisfactory in about 50% of cases without intellectual handicap. Death is rare in childhood epilepsy. Those without severe neurologic handicaps have the same mortality as the general population. We identified only 27 published randomized trials of antiepilepsy drugs in children that compare the efficacy of antiepilepsy drugs, offer treatment of syndromes currently without successful treatment, or have negative effects. There is a pressing need for better definitions of seizures and epilepsy syndromes. The causes of poor social outcome are unclear. Intractability needs a clear definition and randomized trials comparing treatment regimes are sadly lacking.

Risk factors for recurrence of epilepsy and withdrawal of antiepileptic therapy: a practical approach

In epileptic patients, treated with anticonvulsant drugs (AEDs), the question when and how an attempt should be made to withdraw therapy is a crucial point in the management of these patients. In recent years, many studies have identified the main risk factors for seizure recurrence after discontinuation of AEDs. Patients are more likely to have recurrences if there is a definite symptomatic aetiology, two or more different types of seizures, an abnormal neurological examination and a seizure onset at adolescence or later. In contrast, abnormal EEG has not been proved as a risk factor for recurrence. Moreover, the classification of epilepsy syndromes is another important predictor of the outcome for these patients. In practice, most authors suggest that medication is discontinued after a seizure-free period of two years. In this review we analyse data from the literature and we suggest a practical approach for safe anticonvulsant withdrawal, although the decision should always be made individually, weighing risks and benefits.

Launching a research initiative: the Canadian Pediatric Epilepsy Network (CPEN)

The Canadian Pediatric Epilepsy Network is a network of scientists and health care professionals in partnership with organizations which provide education and support to children with epilepsy. The objective of the network is to gain a better understanding of childhood epilepsy through collaborative research conducted with doctors, psychologists, nurses, social workers, educators and scientists across Canada. The network was launched at a meeting in Ottawa in the spring of 2000 where several oral presentations addressed the issues of the fundamental questions of epilepsy, the economic impact and the neuropsychology of childhood epilepsy. The intent was to provoke discussion on future areas of research for the network.

Current evidence indicates that antiepileptic drugs are anti-ictal, not antiepileptic

Despite the large number of available drugs for epilepsy, the primary function of pharmacological therapy is the suppression of seizures, rather than the elimination of their underlying etiology, i.e. an antiepileptic effect. This paper suggests methods by which drugs could be tested for antiepileptic properties and reviews whether current antiepilectic drugs (AEDs) are antiepileptic in addition to being effective for seizure suppression.

Can anticonvulsant drug therapy "cure" epilepsy?

There is now evidence to show that, as time passes, epilepsy, even if untreated, tends to undergo spontaneous remission in a significant proportion of patients. The question therefore arises as to whether anticonvulsant drug therapy increases this chance of the patient with epilepsy ultimately entering a terminal remission which continues after the treatment is withdrawn, i.e. whether anticonvulsant drug therapy itself may sometimes cure epilepsy. There are no well-designed studies available in the literature that provide a clear answer to this question. However, data from a number of investigations carried out for other purposes can be used to see whether contemporary anticonvulsant drug therapy is associated with higher rates of expected untreated terminal remission than those that apply for never-treated patients with epilepsy, or for those whose anticonvulsant treatment has probably been inadequate for various social or historical reasons. Despite the admitted uncertainties inherent in drawing conclusions from such material, there appears to be a reasonably consistent tendency for contemporary anticonvulsant drug treatment to be associated with a greater chance of achieving probable cure of epilepsy. Therefore it would appear premature to take the view that contemporary anticonvulsant drug therapy does no more than suppress epileptic seizures until epilepsy remits spontaneously, or fails to remit, with the passing of time.

The prognosis of epilepsy

The cardinal question for a person developing seizures is 'What is the likelihood that they will go away?' 'Prognosis' refers to the possible outcomes of a disease and the frequency at which they can be expected to occur. Prognostic factors may include demographic features, disease-specific indicators (e.g. seizure frequency, aetiology of epilepsy) or co-morbidity. Such factors do not necessarily cause the outcome, but they are associated strongly with the outcome measured. They are distinct from risk factors--which are associated with the initial development of the disorder. Ideas about the outcome for epilepsy have been altered radically in the past century by study of its epidemiology. The prognosis for epilepsy comprises a number of measurable end-points: the prediction of recurrence after a single unprovoked seizure, the chance of remission after the diagnosis of epilepsy and the risk of premature death.

Early versus late antiepileptic drug withdrawal for people with epilepsy in remission

BACKGROUND

Antiepileptic drugs ( AEDs) are used to prevent seizures but are associated with both short and long term adverse effects. When epilepsy is in remission, it may be in the patient's best interest to discontinue medication. However, the optimal timing of AED discontinuation is not known.

OBJECTIVES

To quantify seizure relapse risk after early (less than two seizure free years) versus late (more than two seizure free years) AED withdrawal in adult and pediatric epilepsy patients. To assess which variables modify the risk of seizure recurrence.

SEARCH STRATEGY

We searched the Cochrane Epilepsy Group trials register, the Cochrane Controlled trials register (Cochrane Library Issue 4, 2000), MEDLINE (January 1996 to January 2001), EMBASE, Index Medicus, CINAHL, as well as hand-searching of journals.

SELECTION CRITERIA

Randomized controlled trials that evaluate withdrawal of AEDs after varying periods of seizure remission in adult and pediatric epilepsy patients with or without blinding were included. Included studies compared an early versus late AED discontinuation.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. Relative risks with 95% confidence intervals were calculated for each trial. Summary relative risks and 95% confidence intervals for dichotomous data were calculated using a random effects model. A test of statistical heterogeneity was conducted for each pooled relative risk calculation.

MAIN RESULTS

Seven eligible controlled trials were included in the analysis representing 924 randomized pediatric patients. There were no eligible trials evaluating adult seizure free patients. The pooled relative risk for seizure relapse in early versus late AED withdrawal was 1.32 (95% confidence interval 1.02 to 1.70). On the basis of this estimate, the number needed to harm, that is expose an individual to a higher risk of seizure relapse because of early withdrawal of AED, is 10. Early discontinuation was associated with greater relapse rates in patients with partial seizures[pooled RR = 1.52; 95% confidence interval 0.95 to 2.41] or an abnormal EEG [pooled RR=1.67; 95% confidence interval 0.93 to 3.00].

REVIEWER'S CONCLUSIONS

There is evidence to support waiting for at least two or more seizure free years before discontinuing AEDs in children, particularly if individuals have an abnormal EEG and partial seizures. There is insufficient evidence to establish when to withdraw AEDs in pediatric patients with generalized seizures. There is no evidence to guide the timing of withdrawal of AEDs in adult seizure free patients. Further blinded randomized controlled trials are needed to identify the optimal timing of AED withdrawal and risk factors predictive of relapse.

Relapse risk analysis after drug withdrawal in epileptic children with uncomplicated seizures

In an attempt to find the risk of relapse and factors predictive of risk of relapse, 97 children with epilepsy, withdrawn from their medication, followed in our outpatient clinic from 1990 to 1995 were included in this study. The overall relapse rate was 20.6%. All relapses occurred within 2 years after withdrawal started. Female gender, age at onset of seizures of more than 2 years, and the duration of withdrawal were found to be significant risk factors in relapse rate following univariate analysis. However, gender was not found to be significant in multivariate analysis. All other factors, including the duration of seizures prior to starting antiepileptic drug (AED) treatment, the number of seizure before the start of AED treatment, the period between AED induction and control of seizures, diagnostic yield from electroencephalogy (EEG) at diagnosis, the number of seizures after the onset of AED therapy, length of seizure-free period, aetiology of the seizures, a history of epilepsy in the immediate family, or previously experienced febrile convulsions were not significant factors in relapse rate. Significant risk factors for relapse rate also significantly affected relapse time. We conclude that when AED therapy is withdrawn from children with uncomplicated epilepsy, as in our patients, the two important risk factors, age at onset of seizures and the duration of withdrawal, can predict a poor prognosis with a higher relapse rate: this needs taking into consideration.

Early discontinuation of treatment in children with uncomplicated epilepsy: a prospective study with a model for prediction of outcome

PURPOSE

The main purpose of the present study was to identify predictor variables with significant influence on seizure outcome after discontinuation of treatment in children with uncomplicated epilepsy and to analyze whether these variables, included in a prognostic model could identify children in whom 1-year treatment would be sufficient.

METHODS

Before initiation of treatment in children aged 2-16 years with uncomplicated epilepsy, the duration of treatment was randomized to 1 year (group I) or 3 years (group II). At the end of the allotted period, treatment was discontinued in 161 children who had been seizure fre during the previous 6 months. The mean follow-up period after treatment was 5.8 years. Twenty-three predictor variables were analyzed by survival methods regarding their influences on the outcome.

RESULTS

At the latest follow-up check, 60 children (37%) had relapsed. The following predictor variables were selected by multiple regression analysis and constituted a model with a simple scoring system: age at seizure onset; seizure type; generalized, irregular spike-wave activity on EEG after 1 year of treatment; and persistent 3-Hz spike-wave activity after 6 months of treatment in children with absence epilepsy. In group I, the remission rate was 73% in children with high prognostic scores, 10% in children with low scores, and 40% in those with intermediate scores (log-rank test, p = 0.0001).

CONCLUSIONS

After 1 year of treatment, our prognostic model identified children in whom treatment could be withdrawn at that time. Our model should be easily applicable in clinical practices and may be of clinical importance in determining the duration of treatment in children with uncomplicated epilepsy.

Motor impairments in children with epilepsy treated with carbamazepine

Nineteen children with epilepsy were tested on two occasions, first during treatment with carbamazepine (CBZ) and then 6 months later without treatment. Plasma drug concentrations were within the therapeutic limits in all children. The children were examined with a standardized test of gross- and fine- motor functions, the Bruininks-Oseretsky test of motor proficiency. Significant improvements were found in response speed (p < 0.05), in composite fine-motor tests (p < 0.01) and in the total test battery (p < 0.05) after the treatment had been withdrawn. A tendency to improvement was found in the fine-motor subtest of upper limb coordination (p = 0.08). Another group of 12 children was tested twice during treatment with CBZ with an interval of 6 months. No difference was found in this group except for an impairment of the results in the subtest of visual-motor control on the second test occasion (p = 0.05).

A comparison between one and three years of treatment in uncomplicated childhood epilepsy: a prospective study. II. The EEG as predictor of outcome after withdrawal of treatment

PURPOSE

We wished to evaluate the prognostic usefulness of various EEG parameters with respect to remission rates after discontinuation of antiepileptic drug (AED) therapy in children treated for epileptic seizures.

METHODS

Two hundred forty-four children with uncomplicated epileptic seizures were randomized to either 1 or 3 years of treatment with AEDs. The treatment was then discontinued in patients who had been seizure-free during the last 6 months of their allotted time of treatment (n = 154). After treatment discontinuation, the children were followed for at least 2 years. EEG recordings were performed before treatment was initiated and at regular intervals during treatment.

RESULTS

The overall relapse rate was 37%. In many children, the amount of epileptiform activity varied considerably between subsequent recordings made during the treatment. The remission rate was slightly higher for children whose last recordings before AED discontinuation were free of epileptiform activity as compared with children in whom such activity was present. However, children who had irregular generalized spike-wave (SW) activity in the recordings made before discontinuation of treatment had a clearly higher relapse rate (67%) both as compared with children without epileptiform activity (33%) and as compared with children with other types of epileptiform activity (33%) in their last EEG recordings before discontinuation. All children treated for only 1 year whose final EEGs displayed generalized irregular SW activity relapsed.

CONCLUSIONS

We conclude that the presence of epileptiform activity does not in itself necessarily influence prognosis after discontinuation of treatment but that certain types of such activity signal a high risk of relapse.