Intractable epilepsy in a population-based series of mentally retarded children

Low IQ predicts worse long-term seizure outcome after resective epilepsy surgery - A propensity score matched analysis

OBJECTIVE

To describe long-term seizure outcomes in patients with IQ < 70 undergoing resective epilepsy surgery and to analyse whether baseline IQ predicts seizure outcome.

METHODS

Patients undergoing focal resective epilepsy surgery 1995-2017 at age ≥ 4 years were identified in the population-based Swedish National Epilepsy Surgery Register. Two-year, five-year and long-term (10-20-year follow-up) outcomes were analysed. Seizure outcomes of patients with IQ ≥ 70 and IQ < 70 at baseline were compared in the full cohort and between propensity score matched groups.

RESULTS

Follow-up data were available for 884 patients, 79 of whom had IQ < 70. Matched controls were found for 74 of the IQ < 70 patients. Preoperative MRI pathology was unifocal in 54 % and 79 % of IQ < 70 and IQ ≥ 70 patients before matching compared to 58 % and 62 % after matching, respectively. Patients with IQ < 70 achieved significantly worse seizure outcomes at all time points both when analysing the full cohort and the matched groups. After matching, the proportions of seizure-free patients in the IQ < 70 group were 28 %, 32 % and 32 % at the 2-year, 5-year and long-term follow-ups, respectively. Corresponding figures in the IQ ≥ 70 group were 54 %, 62 % and 60 % (p for difference between IQ groups 0.004, 0.002 and 0.049). In the IQ < 70 group, 36 %, 29 % and 45 % had a ≥ 75 % reduction in seizure frequency at the respective three follow-ups.

CONCLUSION

Low preoperative IQ predicts lower chances of seizure freedom after resective epilepsy surgery and few patients with IQ < 70 remain completely seizure-free in the long term. Nevertheless, a significant proportion had a reduction in seizure frequency of at least 75 % at long-term follow-up, indicating an important palliative potential of resective surgery for epilepsy patients with intellectual disability.

Vagal Nerve Stimulation in Epilepsy: Experiences of Participants with Cognitive Deficits

INTRODUCTION

The purpose of this study was to examine patients' experiences of vagal nerve stimulation (VNS) with a special interest in patients with cognitive deficit (CD).

MATERIALS AND METHODS

An open, retrospective study was conducted on 82 patients with pharmacoresistant epilepsy, who were treated with VNS for at least 10 months. Based on the inability to live independently, they were divided into two groups: patients with cognitive deficit (CD group) and patients without cognitive deficit (non-CD group). A specially designed questionnaire was used for semi-structured interviews about patients' experiences of VNS treatment.

RESULTS

Approximately one-third described a continuous reduction of seizure frequency of 50% or more and were regarded as responders. Fewer subjects in the CD group were responders than in the non-CD group. Approximately one-third of all subjects had no positive effect of VNS treatment. More CD patients described additional improvements and the most common were milder seizures and improved alertness. The most commonly reported adverse effect was hoarseness.

DISCUSSION

VNS treatment in patients without CD had better effect on seizure frequency reduction than in patients with CD, but many patients with CD reported other benefits from the treatment.

CONCLUSION

Non-CD patients had higher seizure frequency reduction than CD patients during VNS treatment, but many CD patients described other benefits.

Lacosamide in patients with intellectual disability and refractory epilepsy

The objective of this study was to evaluate the tolerability and efficacy of lacosamide (LCM) in residential patients at our epilepsy centre. We assessed retrospectively 80 patients (mean age 36.2 years, range 18-63 years; 29 female) with intellectual disability (ID) and drug-resistant epilepsy using an industry-independent, non-interventional study design based on standardised seizure records. Evaluation, including calculation of retention rate, was carried out for the intervals 3-6, 9-12 and 21-24 months after LCM initiation. The Clinical Global Impression scale (CGI) was used to allow assessment of qualitative changes in seizure severity and clinical status. CGI improved for 61% of the patients. The responder rate was 48%; ten patients (13%) became seizure free. The response was not related to the degree of ID. The retention rates after 12 and 24 months were 71% and 65%, and were significantly lower in patients taking other sodium-channel blockers (SCBs; 76% vs. 55%). The occurrence of adverse events (AEs) was related to the administration of concomitant SCBs (48% with SCBs vs. 26% without). Sedation (15%), ataxia (13%), vertigo (11%), and nausea (9%) were the commonest AEs. While 60% of our patients had concomitant psychiatric diagnosis, we found no relevant effect of this on challenging behaviour. Adjunctive LCM may provide an antiepileptic treatment option for patients with ID with or without additional psychiatric diagnosis. The occurrence of AEs and the LCM retention rate were affected by concomitant SCB use but not by psychiatric comorbidity.

EEG analysis of seizure patterns using visibility graphs for detection of generalized seizures

BACKGROUND

The traditional EEG features in the time and frequency domain show limited seizure detection performance in the epileptic population with intellectual disability (ID). In addition, the influence of EEG seizure patterns on detection performance was less studied.

NEW METHOD

A single-channel EEG signal can be mapped into visibility graphs (VGS), including basic visibility graph (VG), horizontal VG (HVG), and difference VG (DVG). These graphs were used to characterize different EEG seizure patterns. To demonstrate its effectiveness in identifying EEG seizure patterns and detecting generalized seizures, EEG recordings of 615h on one EEG channel from 29 epileptic patients with ID were analyzed.

RESULTS

A novel feature set with discriminative power for seizure detection was obtained by using the VGS method. The degree distributions (DDs) of DVG can clearly distinguish EEG of each seizure pattern. The degree entropy and power-law degree power in DVG were proposed here for the first time, and they show significant difference between seizure and non-seizure EEG. The connecting structure measured by HVG can better distinguish seizure EEG from background than those by VG and DVG.

COMPARISON WITH EXISTING METHOD

A traditional EEG feature set based on frequency analysis was used here as a benchmark feature set. With a support vector machine (SVM) classifier, the seizure detection performance of the benchmark feature set (sensitivity of 24%, FD_t/h of 1.8s) can be improved by combining our proposed VGS features extracted from one EEG channel (sensitivity of 38%, FD_t/h of 1.4s).

CONCLUSIONS

The proposed VGS-based features can help improve seizure detection for ID patients.

[Predictors factors of refractory epilepsy in childhood]

The aim of this study is to identify early predictors of refractory epilepsy. From 600 epileptic children followed for at least 2 years in the department of neurology of Charles Nicolle hospital of Tunis, were identified children with refractory epilepsy. Controls were children who responded well to antiepileptic drugs and who were seizure free for at least 2years. We collected anamnestic, clinical, neuropsychological and radiological data for all children. We identified 67 children with refractory epilepsy, representing 11.6% of the initial population. At diagnosis, the average age was 9.16 years. Some factors have been identified as predictors of drug resistance epilepsy: age of onset less than one year, partial and atonic seizure, combination of several types of attacks, presence of mental retardation and pyramidal syndrome, abnormal electroencephalogram especially focal abnormalities, spike, amplitude abnormalities, interhemispheric asymmetry; and resistance to first antiepileptic drug. Symptomatic epilepsy, especially if associated with radiological lesions such as hippocampal sclerosis and structural brain malformations, was highly correlated with drug resistance. Our study suggests that the initial presentation of epilepsy could predict long-term outcome to drug resistance epilepsy if a detailed analysis of anamnestic, clinical and complementary data is established.

Conceptualizing lennox-gastaut syndrome as a secondary network epilepsy

Lennox–Gastaut Syndrome (LGS) is a category of severe, disabling epilepsy, characterized by frequent, treatment-resistant seizures, and cognitive impairment. Electroencephalography (EEG) shows characteristic generalized epileptic activity that is similar in those with lesional, genetic, or unknown causes, suggesting a common underlying mechanism. The condition typically begins in young children, leaving many severely disabled with recurring seizures throughout their adult life. Scalp EEG of the tonic seizures of LGS is characterized by a diffuse high-voltage slow transient evolving into generalized low-voltage fast activity, likely reflecting sustained fast neuronal firing over a wide cortical area. The typical interictal discharges (runs of slow spike-and-wave and bursts of generalized paroxysmal fast activity) also have a “generalized” electrical field, suggesting widespread cortical involvement. Recent brain mapping studies have begun to reveal which cortical and subcortical regions are active during these “generalized” discharges. In this critical review, we examine findings from neuroimaging studies of LGS and place these in the context of the electrical and clinical features of the syndrome. We suggest that LGS can be conceptualized as “secondary network epilepsy,” where the epileptic activity is expressed through large-scale brain networks, particularly the attention and default-mode networks. Cortical lesions, when present, appear to chronically interact with these networks to produce network instability rather than triggering each individual epileptic discharge. LGS can be considered as “secondary” network epilepsy because the epileptic manifestations of the disorder reflect the networks being driven, rather than the specific initiating process. In this review, we begin with a summation of the clinical manifestations of LGS and what this has revealed about the underlying etiology of the condition. We then undertake a systematic review of the functional neuroimaging literature in LGS, which leads us to conclude that LGS can best be conceptualized as “secondary network epilepsy.”

Features of a subset of children with complex partial epilepsy requiring combination therapy for effective seizure control

To identify children with complex partial seizures with increased risk for suboptimal seizure control with 1 medication, a computerized database containing all patients seen in the context of a single pediatric neurology practice was reviewed for patients with complex partial seizures. Participants included in analysis were then divided into groups; a group in whom seizure control was attained with a single medication (group 1) and a group for whom 2 or more medications were required for seizure control (group 2). Status epilepticus, developmental disabilities, and the presence of coexisting other seizures/types were also significantly different, with a higher predominance in group 2 children. Patients with status epilepticus, coexistent seizure types, and developmental disabilities should be identified and more carefully followed, with a lower threshold for starting these children on a combination of antiepileptic drugs adhered to.

Underlying neurologic disorders and recurrence rates of status epilepticus in childhood

BACKGROUND

The underlying neurologic disorders of status epilepticus (SE) in childhood remain poorly characterized.

METHODS

We reviewed 249 consecutive patients with SE, aged 1 month to 18 years, who were referred to Tottori University Hospital from 1984 to 2002. After exclusion of SE patients with acute symptomatic etiology and progressive encephalopathy, such as acute encephalitis/encephalopathy, meningitis, head trauma, or metabolic disorders, we analyzed 112 patients, aged 3 months to 14 years, and focused on the epilepsy classification and perinatal brain damage in these patients.

RESULTS

Major underlying neurologic disorders were non-symptomatic epilepsy (41 patients, 36.6%), perinatal brain damage (15 patients, 13.4%), non-syndromic mental retardation (17 patients, 15.2%), and congenital disorders including chromosomal abnormalities (13 patients, 11.6%). In non-symptomatic epilepsy, childhood epilepsy with occipital paroxysms (Panayiotopoulos syndrome, 11 patients) and severe myoclonic epilepsy in infancy (SMEI, 6 patients) were common and had high recurrence rates (81.8% and 66.7%, respectively). In patients with a history of perinatal brain damage, preterm birth, neonatal seizure, asphyxia, and neonatal hypoglycemia were frequent. Neonatal hypoglycemia and neonatal seizure were related to the recurrence of SE (100% and 87.5%, respectively). They were mostly diagnosed as symptomatic occipital lobe epilepsy. Parieto-occipital paroxysms were associated with a high recurrence rate of SE (80.6%).

CONCLUSIONS

Although the underlying neurologic disorders of SE are heterogeneous, three specific epileptic syndromes (Panayiotopoulos syndrome, SMEI, and symptomatic occipital lobe epilepsy secondary to neonatal hypoglycemia and neonatal seizure) were the most common causes of SE and were associated with higher recurrence rates.

Adjunctive pregabalin therapy in mentally retarded, developmentally delayed patients with epilepsy

This retrospective study evaluated the efficacy and tolerability of adjunctive pregabalin (PGB) therapy in mentally retarded, developmentally delayed patients. The primary efficacy measure was the change in the median frequency of seizure days per week between the baseline (8 weeks prior to initiating PGB) and treatment (12 weeks of titration and maintenance) periods. Inclusion criteria were: documented epilepsy treated with antiepileptic drug, at least one seizure during the baseline period, and lack of prior exposure to PGB. Seven patients (four female, three male, mean age=43) with multiple seizure types (generalized tonic-clonic, tonic, partial, and atypical absence) met the inclusion criteria. The mean dose of PGB was 293 mg/day (range=150-350 mg/day). PGB was efficacious, resulting in a significant reduction in the median frequency of seizure days/week between baseline and treatment (1.38 vs 0.50, P=0.018). The 50% responder rate was 71%. The adverse effects at last follow-up (mean 13 months) included weight gain, myoclonus, and sedation.

Vagal nerve stimulation: exploring its efficacy and success for an improved prognosis and quality of life in cerebral palsy patients

Cerebral palsy (CP) continues to pose a cause for major socioeconomic concern and medical challenge worldwide. It is associated with a multi-faceted symptomatology warranting a multi-dimensional management-approach. Recent recognition of neurocognitive impairment and its hopefully possible treatment has opened up a new dimension in its management to the neurologists. Vagal nerve stimulation (VNS) technique is presently emerging as an effective alternative anti-epileptic therapeutic measure in intractable epilepsy. VNS has recently been shown to possess a suppressive effect also on interictal epileptiform discharges (IEDs) that are now being widely accepted as established associates of neurocognitive impairment. In this paper, the author proposes VNS technique implantation in CP patients on account of its dual therapeutic effectiveness, i.e. anti-epileptic and IED-suppression. These two effects are likely to control seizures that are quite often drug-resistant and also improve neurocognition in CP patients, thus hoping for a better overall prognostic outcome and an improved quality of life of the CP patients by VNS.

Seizure precipitants in children with intractable epilepsy

PURPOSE

To investigate the seizure precipitants in children with intractable epilepsy, and to determine any distinctive clinical features contributing to seizures in these patients.

METHODS

A questionnaire and seizure diary prepared by the parents of the patients. Demographic and seizure data were reviewed.

RESULTS

Of 120 patients with intractable epilepsy, 74 (62%) had one (n=43), two (n=23), or three seizure precipitants (n=8). The three most common precipitants were illness or fever (32%), sleep deprivation (13%), and menstruation (10%). Of these precipitants, inducing factors (endogenous origin) were more common than triggering factors (exogenous origin): 73% versus 27%, respectively. Three distinctive clinical features - neurological abnormalities (P=0.01), status epilepticus (P=0.017), and abnormal neuroimaging (P=0.007) - were significantly more common in patients with than in patients without precipitants.

CONCLUSIONS

Prompt recognition and management of seizure precipitants has practical implications for treating patients with refractory epilepsy. Such patients can be counseled to avoid specific precipitants.

Risk factors predicting refractoriness in epileptic children with partial seizures

The aim of this retrospective study was to determine the risk factors associated with intractability to therapy in childhood epilepsy. Fifty children with intractable epilepsy as evidenced by at least 1 epileptic fit per month were included in the study group, whereas the control group consisted of children who did not experience any recurrent seizure for at least 1 year at the time of the study. A chi( 2) test was used to evaluate the relationship between the test variables for the 2 groups, and the estimated relative risk (odds ratio) for each variable was calculated. The risk factors were subsequently determined by logistic multiple regression analysis. Univariate analysis showed that mental retardation, neurological abnormality, neuroradiological abnormality, perinatal anoxia, neonatal convulsion, presence of status epilepticus, and symptomatic etiology were significant risk factors for the development of refractory epilepsy (P < .05). For multivariate logistic regression analysis, age at seizure onset, status epilepticus, mixed type of seizures, and history of frequent seizures (more than once a month) were all found to be significant and independent risk factors for refractory epilepsy, and the number of drugs used in the study group was significantly higher than that in the control group (P < .05). In line with these findings, it was concluded that children who present with epilepsy and have these risk factors should be referred to a center where epileptic surgery is carried out without delay.

Postsurgical Outcome in Pediatric Patients with Epilepsy: A Comparison of Patients with Intellectual Disabilities, Subaverage Intelligence, and Average-Range Intelligence

PURPOSE

Intellectual disabilities are often associated with bilateral or diffuse morphologic brain damage. The chances of becoming seizure free after focal surgery are therefore considered to be worse in patients with intellectual disabilities. The risk of postoperative cognitive deficits could increase because diffuse brain damage lowers the patient's ability to compensate for surgically induced deficits. Several studies in adult patients have indicated that IQ alone is not a good predictor of postoperative cognitive and seizure outcome. Our study evaluated this subject in children and adolescents.

METHODS

Pediatric patients with intellectual disabilities (IQ < or = 70), subaverage intelligence (IQ between 71 and 85), or average-range intelligence (IQ > 85) were matched according to several clinical and etiologic criteria to determine the influence of IQ (N = 66).

RESULTS

No dependency of seizure outcome, postoperative cognitive development, and behavioral outcome on the IQ level was found. All groups slightly improved in attention while memory functions tended to decrease and executive functions were stable. School placement remained unchanged for the majority of patients. Between 67 and 78% were seizure free 1 year after surgery (Engel outcome class I).

CONCLUSIONS

IQ alone is not a good predictor of postoperative outcome in pediatric patients with epilepsy. As with patients of average-range intelligence, the decision to operate on patients with a low level of intelligence should depend on the results of the presurgical diagnostics. If the results of the neuropsychological examination indicate diffuse functional impairment, this should not hinder further steps, if all other findings are consistent.

The epidemiology of epilepsy in Europe - a systematic review

Population-based epidemiological studies on epilepsy are available mainly from the UK and the Nordic, Baltic and western Mediterranean countries. No studies were identified from large areas of Europe, especially from the former eastern Europe (except the Baltic countries) and the eastern Mediterranean countries. Based on the prevalence of epilepsy in different studies and accounting for incomplete case identification the estimated number of children and adolescents in Europe with active epilepsy is 0.9 million (prevalence 4.5-5.0 per 1000), 1.9 million in ages 20-64 years (prevalence six per 1000) and 0.6 million in ages 65 years and older (prevalence seven per 1000). Approximately 20-30% of the epilepsy population have more than one seizure per month. Based on the age-specific incidence rates in European studies, the estimated number of new cases per year amongst European children and adolescents is 130,000 (incidence rate 70 per 100,000), 96,000 in adults 20-64 years (incidence rate 30 per 100,000) and 85,000 in the elderly 65 years and older (incidence 100 per 100,000). The proportion of both new and established cases with epilepsy in the young, adults and elderly in individual countries may differ substantially from total European distribution because of differences in age structure.

Topiramate in long-term treatment of epilepsy in the intellectually disabled

BACKGROUND

To study the effectiveness of topiramate (TPM) in refractory epilepsy in patients who have intellectual disability (ID).

METHODS

A representative population sample of 57 patients with ID (age range 2-61, mean 32.8) was administered add-on TPM for drug-refractory epilepsy.

RESULTS

Seizure freedom for at least for 6 months was attained by 10 (17%), and seizure reduction of > or = 50% by further 26 (46%). Less than 50% decrease in seizure frequency was found in 16 (29%). TPM was more efficacious in localisation-related than in generalised epilepsies (81% vs. 50%, P=0.019). An at least 50% decrease in seizure frequency was achieved by patients with temporal lobe epilepsy in 100%, continuous spike-waves during sleep syndrome in 75%, Lennox-Gastaut syndrome in 52%, and those with infantile spasms in 25% of cases. As great decrease in seizure frequency was found in most patients with cortical dysplasia (83%), acquired encephalopathy with mesial temporal sclerosis (MTS) (75%), and genetic disease associated with MTS (66%). Adverse effects occurred in 10% including two (3%) with seizure aggravation and three (5%) necessitating discontinuation.

CONCLUSION

TPM is an effective antiepileptic drug which is of value in treating people with seizures that are resistant to other antiepileptic medication. As a broad-spectrum drug it may substitute for polypharmacy and, at the same time decrease adverse effects and costs of therapy.

Behavioural and neuropsychological problems in refractory paediatric epilepsies

The associated behavioural and neuropsychological profiles were studied in 573 children with refractory epilepsy, admitted in our residential Rehabilitation and Epilepsy Unit during the period 1984-2000. The aim of this study was to look for possible correlations between epileptic categories and behavioural profiles. The most frequent neuro-behavioural correlates in the different epilepsy categories were pervasive disorders (48/573=8%), attentional problems (43/573=7.5%), loss of self-esteem (n=49 or 9%) and self-induction of seizures (n=34 or 7%). Pervasive disorders were significantly more frequent in secondary generalised epilepsies. In 86/573 children (15%), mental decline due to epileptic process itself was observed. As expected this was seen in all patients with Lennox-Gastaut syndrome, West syndrome, severe myoclonic epilepsy of infancy and in continuous spikes and slow waves during slow wave sleep. The only behavioural problem that was more frequent in females was self-induction of seizures.

Study of seizure and epilepsy in Chinese children in Hong Kong: period prevalence and patterns

The Hong Kong Children's Seizure and Epilepsy Registry was set up for all children with a history of seizures or epilepsy followed up in the Epilepsy Clinic of the University of Hong Kong. The aim was to study the pattern of seizures and epileptic disorders in Chinese children. The objective was to study the period prevalence of epilepsy and the pattern of epilepsy in Chinese children. A prospective study of seizure and epilepsy in Chinese children was conducted from 1985 to 1997 in Hong Kong. The population census of 1997 was used to calculate the period prevalence of epilepsy in Chinese children. Altogether, 1103 children aged < 19 years at first assessment with epilepsy were included in the study. The period prevalence rate of epilepsy in 1997 (January to December) is estimated to be 4.5 per 1000 children aged < 19 years. The estimated period prevalence rate of children and adolescents with epilepsy in our children is 4.5 per 1000 children.

Early predictors of medical intractability in childhood epilepsy

The goal of this study is identify early predictors of intractability in childhood epilepsy. A cohort of epileptic children living in the northwest sector of Hong Kong was prospectively identified and monitored. Treatment effect was analyzed at the last follow-up before July 1, 2000. Cases were patients who had an average of at least one unprovoked seizure per month during an observational period of at least 2 years. Controls were children having achieved at least 2 seizure-free years. Strong univariate association was observed between intractability and the following factors: high initial seizure frequency, remote symptomatic etiology, infantile spasms and mixed seizure types, abnormal neurologic status, history of status epilepticus, neonatal seizures, and early breakthrough attacks after treatment initiation. Independent predictors of intractability with multiple regression were abnormal neurodevelopmental status, symptomatic etiology, and more than three seizures in the second 6 months after treatment. Our study suggested that risk of developing intractable epilepsy might be predicted, to some extent, at the early course of illness in children with abnormal neurologic status and lack of early response to treatment.

Epilepsy in mainstream and special educational primary school settings

This population based study compared the prevalence, nature and management of epilepsy between primary school children in mainstream education and those attending a special educational placement (children with special needs). The overall prevalence of epilepsy was 4.3/1000, but was 30 times higher in children with special needs, many of whom also had severe physical disabilities. Seizure types and the proportion of subjects with multiple seizures were similar in mainstream children and those with special needs. Epilepsy syndromes were identified in 74% of children. Although seizures were better controlled in children at mainstream school, 44% of these children did not have well controlled seizures. Children with epilepsy are an educationally vulnerable group and both education and health staff need to be aware of the additional support that many of these children require in all types of primary educational settings.

Developmental outcome with and without successful intervention

A review of the literature on the developmental outcome of medically and surgically treated symptomatic infantile spasms (IS) indicates that poor seizure control, severe mental retardation, and marked behavioral disorders are found at long-term outcome of symptomatic IS. The 2-year outcome findings of the UCLA Pediatric Epilepsy Surgery Research Group in children with symptomatic infantile spasms and in children with early onset intractable symptomatic epilepsy other than IS (non-IS) demonstrate impaired development of cognition, language, and social communication despite improved seizure control. The social communication deficits of these children are similar to those found in autistic children. Finally, the underlying pathology of the resected brain, rather than ongoing seizures and seizure type, plays an important role in development of the remaining brain tissue and the outcome of early onset symptomatic IS and non-IS.

Concomitant use of divalproex sodium and lamotrigine in developmentally disabled patients with epilepsy: a retrospective evaluation of efficacy and tolerability

Objective. Epilepsy in institutionalized severe developmentally disabled patients poses a therapeutic challenge. Frequently these patients have multiple seizure (sz) types that are often intractable. Both divalproex sodium (VPA) and lamotrigine (LTG) have demonstrated efficacy. We sought to examine the efficacy of this specific combination in a group of institutionalized, developmentally disabled patients with epilepsy.Methods. Medical and pharmacy records of all patients with developmental disabilities and intractable seizures were reviewed to identify those who had received VPA and LTG. This retrospective evaluation was structured with respect to time frame and outcome measure. Phase 1 consisted of baseline monotherapy with VPA. Phase 2 consisted of titration/dose escalation. Phase 3 was treatment observation period with the combination of both. Seizure frequency and adverse effect data were obtained from nursing or residential staff records. Primary outcome measures were change in seizure frequency between Phases 1 and 3. Additional measures were percentage of patients seizure-free and those with >75% reduction in seizures. A Wilcoxan signed rank test was used for statistical analysis.Results. Of 293 patients, 25 (12M/13F, 31.7+/-10.2 years) had VPA monotherapy following which LTG was added. Mean doses of VPA and LTG were 1474+/-728 and 165+/-111mg/day, respectively. Baseline seizure frequency ranged from 1 to 25 per month. Mean seizure frequency significantly decreased (6.5+/-vs2.0+/-4.0seizures/month, P<0.001). Sixty-four percent of these patients had >/=75% reduction in seizures 28% became seizure-free.Conclusions. The combination of VPA and LTG appears efficacious in this group of developmentally disabled patients with intractable seizures. Rash, which has been associated with this combination, was notably absent and this may reflect the slower titration schedule used.

Antiepileptic drug selection in pediatric epilepsy

This review article presents information concerning treatment options for various pediatric epilepsy syndromes. The decisions made in the selection of antiepileptic drugs are deternined by a number of variables that include, but are exclusive of, risk of seizure recurrence, patient age, epilepsy syndrome, known drug reactions, and prognosis of the epilepsy syndrome. The review discusses issues pertinent to antiepileptic drug selection including simple pharmacokinetic principles, antiepileptic drug formulations, and information concerning clinical studies using some of the antiepileptic drugs. Information is provided concerning the issues of seizure recurrence. Suggested paradigms for antiepileptic drug selection for partial seizures are provided. A table of antiepileptic drug costs is provided for assistance in prescribing and advising families. Psychosocial issues pertinent to the treatment of children are discussed.

Convulsive status epilepticus in children with intractable epilepsy is frequently focal in origin

BACKGROUND

Convulsive status epilepticus (CSE) is a common neurological emergency. Our objectives were to study children with recurrent nonfebrile CSE to assess the evidence for focal origin.

METHODS

Series of 18 children with recurrent CSE and intractable epilepsy were identified by chart review. Clinical, radiological, and EEG data were reviewed. Focal structural abnormalities were identified on MRI and CT images by one neuroradiologist who was unaware of the clinical details.

RESULTS

The patient's ages ranged between 6-22 years (mean 15.3, SD 4), and 67% were males. Most children (89%) had a severe cognitive and / or behavioural disorder. Most patients (89%) had multiple seizure types and 95% of these were partial seizures. Twelve (67%) children had at least one episode of CSE with focal features identified clinically. Focal brain abnormalities were detected on 18% and 55% of CT and MRI films respectively. Overall, 53% had a focal abnormality on structural neuroimaging. Interictal EEG revealed focal or multifocal abnormalities on at least one occasion in 94% and 22% of patients respectively. Overall, 17 patients had focal features on at least one EEG. Thirteen ictal EEGs were recorded on 11 (61%) patients. Ten (91%) of these recordings revealed a focal onset.

CONCLUSIONS

Many handicapped children with recurrent CSE have focal clinical, radiological, or electrographic features. This supports a focal origin for CSE in most children with intractable epilepsy.

Vagus Nerve Stimulation for Patients in Residential Treatment Facilities

THIS ANALYSIS COMPARED THE EFFECTIVENESS OF VAGUS NERVE STIMULATION (VNS) THERAPY AMONG PATIENTS WITH INTRACTABLE SEIZURES: a group living in residential treatment facilities (RTF) with a group not living in RTFs (non-RTF). Among a constant cohort of patients with baseline, 3-month, and 12-month data, the RTF group had significantly (P < 0.05) larger numbers of patients with generalized seizures, previous callosotomy, psychiatric disorders, behavioral problems, and Rett's syndrome. Median seizure reductions after 3 months were 33% in the RTF group and 49% in the non-RTF group (P < 0.001); after 12 months, 50% (RTF) and 56% (non-RTF). After both 3 and 12 months, alertness, mood, postictal recovery, and cluster seizures improved in more than a third of patients in both groups. Because VNS therapy does not interact with medications and is delivered automatically, it should be seriously considered for patients with intractable epilepsy who reside in RTFs.

Topiramate in the catastrophic epilepsies of childhood

Several epileptic syndromes that occur during childhood are characterized by severe treatment-resistant seizures, progressive loss of higher intellectual functions, and characteristic electroencephalographic abnormalities. These catastrophic epileptic syndromes include epileptic encephalopathy with diffuse slow spike waves (Lennox-Gastaut syndrome), West syndrome, progressive myoclonic epilepsies, and electrical status epilepticus during sleep. This article summarizes each syndrome and reviews the most recent information concerning the effectiveness of topiramate with respect to each condition. Suggestions are offered to help clinicians maximize topiramate's efficacy and tolerability in patients suffering with these syndromes. Overall, topiramate is a valuable antiepileptic medication in the treatment of catastrophic pediatric epileptic syndromes.

Long-term follow-up study of Lennox-Gastaut syndrome in patients with severe motor and intellectual disabilities: with special reference to the problem of dysphagia

A long-term follow-up study of Lennox-Gastaut syndrome (LGS) ( > 10 years) was conducted with 38 patients with severe motor and intellectual disabilities (SMID) to clarify the relationship between the rapid development of dysphagia and epileptic seizures, and to elucidate the long-term evolution of LGS in patients with SMID. Those who showed a relatively favourable seizure outcome were compared to those with a poor seizure outcome. Poor seizure outcome correlated strongly with: (a) an early appearance of dysphagia and additional deterioration of the already retarded mental function; (b) a predominance of atypical absence seizures; and (c) persistent frequent epileptiform discharges during electroencephalographic evaluations. Neither age at seizure onset nor intelligence level at the time of the last examination was correlated with seizure prognosis. Further, seizure prognosis was not related to the aetiology of LGS. Repeated seizures apparently caused development of progressive epileptic encephalopathy, in addition to the underlying severe brain damage. Since development of dysphagia burdens an already severely handicapped patient with intensive medical care, efforts to reduce the seizures and design a long-term care plan are of great importance.

Theoretical and practical considerations in the psychological and educational assessment of the student with intractable epilepsy: dynamic assessment as an adjunct to static assessment

Assessing the student with intractable epilepsy requires skill not only in evaluating cognitive problems, but also detecting seizures and discovering how to adapt instruction to minimize their negative impact on learning. Ironically, assessment efforts are seen as compromised by the occurrence of seizures during testing, when determining how seizure events may interfere with learning and the instructional modifications that are necessary to cope with them, should be a key part of assessment. A dual approach to assessment is recommended that combines the identification of cognitive deficits with an evaluation of how recurring seizures may prevent the student from engaging in instruction. Without also evaluating the student's response to instruction, teaching to specific cognitive needs is limited by insufficient knowledge about how to keep the student involved in instruction when seizures occur. Static assessment evaluates cognitive functioning at the time of testing, without changing the way that the student learns and responds. By engaging the student in teaching/learning sessions, dynamic assessment explores how the student best learns despite cognitive deficits and the disruptive effect of seizures. This paper includes a description of the authors'experience in using dynamic assessment as an adjunct to static assessment in evaluating a student with intractable epilepsy.

Lack of an effect of valproate concentration on lamotrigine pharmacokinetics in developmentally disabled patients with epilepsy

PURPOSE

to describe the population pharmacokinetics of lamotrigine (LTG) in developmentally disabled (DD) patients with epilepsy and (2) to determine if there is an effect of valproate (VPA) concentration on the extent of the pharmacokinetic interaction between VPA and LTG.

METHOD

a NONMEM population analysis of steady-state LTG serum concentrations was conducted in patients receiving LTG either as mono or polytherapy with either an enzyme inducer (IND)-carbamazepine (CBZ), phenytoin (PHT), phenobarbital (PB) or an inhibitor (VPA).

RESULTS

sixty-two patients (33.6+/-11.3 years, 47+/-9.9 kg) receiving LTG monotherapy (n=19) or polytherapy with VPA (n=15), inducer(s) (n=32) or both (n=5) were evaluated. LTG dose of 369+/-236 mg per day (8.1+/-5.9 mg/kg per day) achieved LTG plasma concentrations of 6.8+/-3.3 microg/ml. The observed LTG monotherapy, LTG+IND, and LTG+VPA oral clearance (Cl/F) were 0. 69+/-0.2, 1.60+/-0.65 and 0.2+/-0.05 ml/kg per min, respectively. The final LTG Cl/F model was dependent on body weight, concomitant VPA, and either single or multiple inducers. Including the serum concentrations of CBZ, PHT, or VPA in the model, did not significantly improve estimates of Cl/F.

CONCLUSION

LTG Cl/F in DD patients is similar to literature values for ambulatory adult patients; however, low weight adult patients have higher elimination rates, as well as an increased response to enzyme induction. VPA inhibition of LTG Cl/F is maximal within the usually accepted therapeutic range for VPA.

Epilepsy surgery in children with developmental disabilities

Surgery for treatment of medically uncontrolled epilepsy in children is now widely accepted with reported outcomes similar to those in adults. Epilepsy is reported in 8.8% to 32% of children with mental retardation (MR) and in up to half of children with severe retardation. There has been concern that patients with low IQ will experience unsatisfactory outcomes from epilepsy surgery and not achieve good seizure control. It is appropriate to reassess the prior bias against resective epilepsy surgery in children with MR in view of the changing criteria for potential candidacy for epilepsy surgery in infants and young children. There are three prerequisites for epilepsy surgery: (1) the epilepsy must be medically intractable; (2) the surgery must be feasible, that is, the epileptogenic zone can identified and safely resected; and (3) there is high likelihood of a satisfactory outcome as regards both the epilepsy and the patient's functional status. Patients with MR may have diffuse cerebral dysfunction and diffuse or multifocal epileptogenic regions. Appropriate patient selection is made possible through use of current technology that allows identification of lesions or areas of cerebral dysgenesis, aiding in identification of localized areas of epileptogenesis. Results from various series of patients with MR who have undergone resective surgery for epilepsy have shown that with careful presurgical evaluations, outcomes are similar between patients with normal IQ scores and those with low scores. Surgical protocols specifically for patients with MR and intractable epilepsy are required, including careful definition of desired outcomes.

Surgery for malformations of cortical development causing epilepsy

Malformations of cortical development (MCD) are responsible for many cases of refractory epilepsy in adults and children. The results of surgical treatment are difficult to assess from the published literature. Judging from the limited number of adequately reported cases, approximately 40% of all cases of MCD treated surgically may be rendered seizure-free over a minimum 2-year follow-up period. This figure is the same for focal cortical dysplasia (FCD), the most common variety of MCD in surgical reports. In comparison with outcome for epilepsy associated with hippocampal sclerosis, this figure is low. Part of the difference may be artificial and related to limited reporting. Much of the difference is likely to relate to the complex underlying biology of MCD. Analysis of epileptogenesis in MCD has been undertaken. Different types of MCD have different sequelae. Some varieties are intrinsically epileptogenic; these include FCD and heterotopia. Although in most cases, the visualized MCD lies within the region of brain responsible for generating seizures (the epileptogenic zone), it may not constitute the entire epileptogenic zone in all cases. For polymicrogyria and schizencephaly in particular, the visualized abnormalities are probably not the most important component of the epileptogenic zone. There is evidence that the epileptogenic zone is spatially distributed and also, in some cases, temporally distributed. These findings may explain poor surgical outcome and the inadequacy of current presurgical evaluative methods. New preoperative techniques offer the opportunity of improved presurgical planning and selection of cases more likely to be rendered seizure-free by current surgical techniques. Of paramount importance is improved reporting. The establishment of a central registry may facilitate this aim. Specific recommendations are made for surgical strategies based on current experience and understanding.

Efficacy of lamotrigine in institutionalized, developmentally disabled patients with epilepsy: a retrospective evaluation

The paper evaluates the efficacy of the newer anticonvulsant lamotrigine in a developmentally disabled patient population. A retrospective evaluation was done at two institutional centres to assess adjunctive lamotrigine (Lamictal) efficacy in a developmentally disabled population. Mean seizure frequency was compared between a 2-month pre-lamotrigine baseline period and a 2-month treatment period. A 3-month lamotrigine titration phase occurred between baseline and treatment periods. Seizure frequency data was obtained from standardized, daily seizure records. Adverse effect data was obtained from medical and nursing notes. An intent to treat analysis was performed. Data were analysed using Student's t-test for paired data. We evaluated 44 centre residents (25 male, 19 female, average age 33 +/- 11 years). Mean lamotrigine dose was 272 +/- 133 mg per day. A significant reduction in seizure frequency was noted. Seizure frequency (all seizures) was 10.1 +/- 11.2 during the baseline period vs. 5.8 +/- 7.9 seizures per month during the treatment period (P = 0.002). Thirty-two percent of patients (n = 14) had greater than a 75% reduction in seizure frequency. Twenty-three percent of patients (n = 10) had a 50-74% seizure reduction. Twenty-five percent of patients (n = 11) had less than a 50% reduction in seizures, while 20% (n = 9) had an increase in seizures. A significant reduction of 48% in generalized seizures (9.5 +/- 11.6 vs. 4.9 +/- 6.5 seizures per month, P = 0.013) was noted. Reductions in partial seizure frequency of 48% (7.9 +/- 10 vs. 4 +/- 6.6 seizures per month, P = 0.16) as well as in mixed-type seizures (19.9 +/- 9.3 was vs. 15 +/- 12.1 seizures per month, P = 0.11) were also seen; however, these changes did not reach significance. Overall, lamotrigine was well tolerated by the subject population. Adjunctive treatment with lamotrigine appears to be an efficacious and well-tolerated treatment for seizures in a significant percentage of developmentally disabled patients with epilepsy.

Early predictors of intractability in childhood epilepsy: a community-based case-control study in Copparo, Italy

OBJECTIVES

To identify early predictors of intractability in childhood and adolescence epilepsy.

MATERIALS AND METHODS

We carried out a community-based case-control study using the incidence cohort of epileptic patients living in the district of Copparo, in the province of Ferrara, Italy. The comparative study was performed in 31 cases and 95 controls. Cases were patients who averaged at least 1 unprovoked seizure per month during an observational period of at least 2 years. Controls were subjects having achieved remission for at least 5 years regardless of current therapy.

RESULTS

Onset at age <1 year, remote symptomatic etiology and high frequency of seizures before therapy were found to be independent early predictors of intractability.

CONCLUSION

Our study suggested that the risk of developing intractable epilepsy may, to some extent, be predicted at the time of initial diagnosis in children with early-onset epilepsy of remote symptomatic etiology, especially if seizure propensity is initially high.