ILAE classification of epilepsies: its applicability and practical value of different diagnostic categories. Osservatorio Regionale per L'Epilessia (OREp), Lombardy

Epilepsy at different ages-Etiologies in a Norwegian population

The causes of epilepsy are age related, but confirmative data from population-based studies are scarce. Our aim was to describe the typical causes of epilepsy in the different age groups of a defined population. The study was cross-sectional, based on a review of all medical files containing a diagnostic code for epilepsy at Drammen Hospital from 1999-2013. Drammen Hospital serves the population of Buskerud County, with 272 228 residents (as of January 1, 2014), including 1771 people with active epilepsy. This group of persons with active epilepsy was divided into different age groups with the causes of epilepsy mapped in each group. The proportion with unknown etiology ranged from 27% (age 5-9) to 41% (age 10-19). Structural-metabolic epilepsy and perinatal insults were the leading causes of epilepsy in the age group 5-9 (46%), whereas disturbances of brain development dominated in the youngest (23% in patients ≤4 years old). In the group comprising persons with epilepsy ≥60 years old, stroke was the most common cause of epilepsy (44%). Despite recent advances in research and technology, a large number of patients in all age groups (including the youngest) still have an unknown cause of epilepsy. We conclude that an effort must be made to improve the diagnostics for and understanding of the causes of epilepsy across all ages.

Psychosocial complications in juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) constitutes about 10% of all epilepsies. Because of executive dysfunction, people with JME may be prone to impulsivity and risk-taking behavior. Our aim was to investigate whether psychosocial issues associated with impulsivity are more prominent in people with JME than in those with other types of genetic generalized epilepsy (GGE). Patients with GGE were recruited retrospectively through the Drammen Hospital records in Buskerud County, Norway, 1999-2013. They were invited to a semi-structured interview, either at the hospital or at home. Ninety-two patients with JME and 45 with other types of GGE were interviewed. Variables were evaluated in terms of their association with JME versus other GGE diagnosis using a logistic regression model. Juvenile myoclonic epilepsy was associated with use of illicit recreational drugs and police charges, although with borderline significance (odds ratio [OR] 3.4, p = 0.087 and OR 4.2, p = 0.095); JME was also associated with being examined for attention-deficit hyperactivity disorder (ADHD) in females (OR 15.5, p = 0.015), a biological parent with challenges like addiction or violent behavior (OR 3.5, p = 0.032), and use of levetiracetam (OR 5.1, p = 0.014). After controlling for group differences, we found psychosocial complications to be associated with JME, potentially influencing the lives of the individuals and their families to a greater extent than the seizures per se. Thus, JME should be considered a disorder of the brain in a broader sense than a condition with seizures only.

Comparing two classification schemes for seizures and epilepsy in rural China

BACKGROUND AND PURPOSE

The International League against Epilepsy (ILAE) updated the classifications of seizures and epilepsies in 2017. The 2017 classifications were compared with the 1980s classifications in rural China.

METHODS

People with epilepsy receiving treatment under the National Epilepsy Control Programme were recruited from rural areas in China. Their seizures and epileptic syndrome were classified using the 1980s ILAE classification system and then re-classified according to the 2017 system. Differences in seizure, epilepsy and aetiology classifications were identified.

RESULTS

A total of 597 individuals (58% males, aged 6-78 years) were included. Amongst them 535 (90%) had a single seizure type, 57 (9.55%) had two types and five (0.84%) had three. There was complete agreement between the 1981 and 2017 classifications for the 525 individuals with focal seizures. Seizures originally classified as generalized in 10 of 65 individuals were re-classified as unknown in the 2017 classification. Compared to the 1980s classifications, the proportion of individuals with unknown seizures and unknown epilepsy increased from 1.2% (7/597) to 2.8% (17/597, P = 0.002), and unknown aetiology increased from 32% (189/597: 182 cryptogenic and seven unclassified) to 39% (230/597; P < 0.001) in the 2017 classifications.

CONCLUSIONS

The 1980s and 2017 classifications had 100% agreement in classifying focal seizures and epilepsy in rural China. A small but significant proportion of generalized seizures and epilepsy and aetiologies classified in the old classifications were re-classified to unknown in the new classifications. These results highlight the need for improvement in clinical evaluation of people with epilepsy in resource-poor settings.

Applicability of the new ILAE classification for epilepsies (2010) in persons with epilepsy at a tertiary care center in India

PURPOSE

To test the applicability of the new International League Against Epilepsy (ILAE) 2010 classification for epilepsies and to compare it with the ILAE 1989 classification and the ILAE 2001 diagnostic scheme in developing countries with limited resources such as India.

METHODS

Prospective data of 500 consecutive patients with epilepsy, presenting in neurology department of All India Institute of Medical Sciences, was collected from January 2011 to June 2012 and analyzed according to the three systems proposed by ILAE in 1989, 2001, and 2010.

KEY FINDINGS

All 500 patients could be classified in the ILAE 1989 classification system, but only 413 in the ILAE 2001 diagnostic scheme (in axes 3 and 4) and 420 in the ILAE 2010 classification system. Leading categories were localization-related epilepsies, symptomatic focal epilepsies, perinatal insult, and epilepsies attributed to structural and metabolic cause in ILAE 1989, 2001 axis 3, 2001 axis 4, and 2010 systems, respectively. The ILAE 1989 classification system could categorize significantly greater numbers of patients compared to the 2001 and 2010 systems, whereas the latter two remained similar.

SIGNIFICANCE

A large group of patients remained unclassified in the new classification system despite our tremendous gain in knowledge through improved imaging, genomics, and molecular biology, and so on, which could be attributed to lack of availability of facilities in developing countries. Dichotomy of localization-related and generalized epilepsy still makes for a fundamental and pragmatic working diagnosis and guides the physician about the extent of investigations and treatment especially in "epilepsies of unknown cause."

Prediction of seizure outcome in childhood epilepsies in countries with limited resources: a prospective study

AIM

To identify predictors of seizure control in newly presenting children with epilepsy in countries with limited resources.

METHOD

Three hundred and ninety children (273 males, 117 females) aged 2 months to 15 years with newly diagnosed epilepsy were enrolled prospectively at first visit to the multidisciplinary clinic at the children's hospital in Dhaka, Bangladesh. Data about seizures, motor disability, psychomotor development, and electroencephalography were obtained. Regular monitoring of antiepileptic drug treatment was continued at least for one year. Associations between seizure control and potential predictors were determined by multivariate analysis.

RESULTS

Three hundred and ninety children were enrolled in 6 months, of whom over 60% were from low-income families, 60% had onset at under 1 year, 74% had more than one seizure per week, 69% a single-seizure type, and 38% a history of delayed onset of breathing at birth. Cognitive deficits (IQ<70; 58%) and/or motor (significant limitation of daily living activities; 47%) deficits were common. After 1 year of regular treatment, seizure control was good (seizure freedom) in 53%, and poor (at least one seizure in the last 3mo of follow-up) in 47%. The predictors of poor seizure control were an IQ<70, associated motor disability, multiple seizure types, and a history of cognitive regression (1.9 times more likely to have poor seizure control).

INTERPRETATION

Seizure control can be predicted using three clinical factors (motor disability, cognitive impairment, and multiple seizure types) at the first clinic visit. Such predictors assist the development of referral plans and management guidelines for childhood epilepsies in resource-poor countries.

Epidemiology of idiopathic generalized epilepsies

Idiopathic generalized epilepsies (IGEs) are a relatively new category of disorders defined by strict clinical and electroencephalogram (EEG) features proposed by the International League Against Epilepsy (ILAE) classification of epileptic syndromes. IGEs are usually easy to diagnose when clinical and EEG data are collected, but epilepsy is not synonymous with epileptic syndrome. So far, IGEs are studied in the large group of epilepsies of undetermined or unknown etiology although the genetic origin is now largely accepted. ILAE-proposed criteria are helpful in the clinical and therapeutic management of IGEs, but many epidemiologic studies still confuse the cryptogenic and idiopathic groups. Some syndromes in childhood, which are completely described by strict electroclinical criteria such as the absence epilepsies, juvenile myoclonic epilepsies, are usually included and analyzed in epidemiologic studies; however, other epileptic syndromes observed in infancy, such as benign familial neonatal seizures and benign myoclonic epilepsy in infancy, are quite rare and are usually excluded from epidemiologic surveys because they are difficult to describe completely in electro-clinical terms. Another strong limitation in the study of epidemiology of IGEs is the lack of EEG data, either because EEG is not available or the routine EEG is normal. This is particularly relevant in the inclusion of patients with only tonic-clonic seizures. IGEs encompass several different syndromes, and a few patients shift from one phenotype to another. The overlapping of some syndromes during infancy and adolescence increased the difficulty to individualize strictly the correct syndrome. Many discrepancies can be observed in the distribution of the different syndromes included in the group of IGEs, because the strict criteria for classifying these syndromes proposed by the ILAE are often not respected. With this understanding, the general frequency of IGEs can be assessed at 15-20% of all epilepsies. The frequency and the distribution of incidence and prevalence of the different syndromes are tentatively reported and discussed. When the term idiopathic is used following the restrictive ILAE criteria, the mortality data concerning patients with idiopathic epilepsies do not show an increased standardized mortality ratio.

One-Year Mortality in Bordeaux Cohort: The Value of Syndrome Classification

PURPOSE

To evaluate the usefulness of the International Classification of Epilepsy Syndromes for 1-year mortality in a prospective incidence study of first epileptic seizures.

METHODS

Date and cause of death from the treating physician in an incidence study of first afebrile seizures collected 15 years ago in Southwest France. Cases were classified by epilepsy syndrome. A total of 804 patients were included: acute symptomatic (n = 277), unprovoked (n = 439), or unclassifiable (n = 88).

RESULTS

One hundred and fifty-one patients died within the first year: none with idiopathic partial or generalized epilepsy, 16/104 with symptomatic (standardized mortality ratio (SMR) 6.4, 95% CI 3.6-10.3), 1/59 with cryptogenic (SMR 1.7, 95% CI 0.1-9.7 CI) partial epilepsy, 1/14 (SMR 28.1, 95% CI 0.4-156.6) with symptomatic/cryptogenic generalized epilepsy, 2/23 with undetermined epilepsy, 1/135 with isolated seizure (SMR 0.6, 95% CI 0.1-3.1), and 90/277 (SMR 10.3, 95% CI 8.3-12.7) with acute symptomatic seizures. Unclassifiable seizures could not be classified as acute symptomatic or unprovoked: associated with alcohol abuse (death: 3/32, SMR 7.7, 95% CI 1.6-22.6), brain tumors (death: 31/39, SMR 41.5, 95% CI 28.2-58.9), and dementia (death: 6/17, SMR 5.4, 95% CI 2.0-11.7). Most deaths were due to progression of underlying disease, only 5.9% were seizure-related.

CONCLUSIONS

Although a syndromic diagnosis is important for treatment decisions and some prognostic aspects of seizure disorders, its value in mortality studies is limited. Mortality can be calculated only at the first (partial, generalized, and undetermined epilepsies, and special syndromes) and the second (idiopathic vs. symptomatic or cryptogenic) levels of the International Classification of Epilepsies.

Urban prevalence of epilepsy: populational study in São José do Rio Preto, a medium-sized city in Brazil

The aim of this study was to determine the prevalence of epilepsy in the urban population of São José do Rio Preto. This is a medium-sized city of 336000 inhabitants, located in the northwest of the state of São Paulo, Brazil. METHOD: A crosssectional epidemiological investigation with a randomized sample was performed in two phases, a screening phase and a confirmation of the diagnosis phase. The gold standard was a clinical investigation and neurological examination. The chi-square test was used in analysis of the results and p-value value < 0.05 was considered significant. Prevalence was calculated with 95% confidence interval. RESULTS: The study sample size was 17293 individuals, with distributions of gender, age, and race similar to the general population. The prevalence per 1000 inhabitants of epilepsy was 18.6, of these 8.2 were active, defined as at least one seizure within the last two years. The prevalence per 1000 inhabitants for the age groups (years) was 4.9 (04), 11.7 (514), 20.3 (1564) and 32.8 (65 or over). CONCLUSION: Prevalence of both accumulated and active epilepsy was elevated, comparable to other developing nations, in particular those of Latin America. However, the prevalence of epilepsy in childhood was low, whilst in aged individuals it was high similar to industrialized nations.

Specific Epileptic Syndromes Are Rare Even in Tertiary Epilepsy Centers: A Patient‐oriented Approach to Epilepsy Classification

PURPOSE

To assess the practicability and reliability of a five-dimensional patient-oriented epilepsy classification and to compare it with the International League Against Epilepsy (ILAE) classification of epilepsy and epileptic syndromes. The dimensions consist of the epileptogenic zone, semiologic seizure type(s), etiology, related medical conditions, and seizure frequency.

METHODS

The 185 epilepsy patients (94 adults, 91 children, aged 18 years or younger) were randomly selected from the database of a tertiary epilepsy center and the general neurological department of a metropolitan hospital (28 adults). The charts were reviewed independently by two investigators and classified according to both the ILAE and the patient-oriented classification. Interrater reliability was assessed, and a final consensus among all investigators was established.

RESULTS

Only four (4%) adults and 19 (21%) children were diagnosed with a specific epilepsy syndrome of the ILAE classification. All other patients were in unspecific categories. The patient-oriented classification revealed that 64 adults and 56 children had focal epilepsy. In an additional 34 adults and 45 children, the epileptogenic zone could be localized to a certain brain region, and in 14 adults and five children, the epileptogenic zone could be lateralized. Fourteen adults and 21 children had generalized epilepsy. In 16 adults and 14 children, it remained unclear whether the epilepsy was focal or generalized. Generalized simple motor seizures were found in 66 adults and 52 children, representing the most frequent seizure type. Etiology could be determined in 40 adults and 45 children. Hippocampal sclerosis was the most frequent etiology in adults (10%), and cortical dysplasia (9%), in children. Seven adults and 31 children had at least daily seizures. Seventeen adults and 26 children had rare or no seizures at their last documented contact. The most frequent related medical conditions were psychiatric disorders and mental retardation. Interrater agreement was high (kappa values of 0.8 to 0.9) for both the patient-oriented and the ILAE classification.

CONCLUSIONS

Specific epilepsy syndromes included in the current ILAE classification are rare even in a tertiary epilepsy center. Most patients are included in unspecific categories that provide only incomplete information. In contrast, all of the patients could be classified by the five-dimensional patient-oriented classification, providing all essential information for the management of the patients with a high degree of interrater reliability.

Incidence of adult epilepsy in Estonia

PURPOSE

To estimate the main incidence-related characteristics of epilepsy in an adult population in Estonia. Epidemiologic data about epilepsy from central and eastern Europe is controversial.

METHODS

All existing databases and lists in the area were reviewed to identify all persons with newly diagnosed epilepsy aged > or =20 years during 3 years. Special attention was paid to extensive adoption of definitions and criteria proposed by Guidelines for epidemiologic studies.

RESULTS

Crude and age-adjusted incidence rates were 35 per 100,000 person-years. The age-specific rates tended to increase with advancing age. Of the seizure types, partial seizures had highest rates, 27 per 100,000. The largest syndromic categories were localization-related epilepsies. Risk factors for epilepsy were identified in 55.5% cases.

CONCLUSIONS

Incidence-related characteristics in the adult population of Tartu was comparable with those reported from the developed countries. The predominance of localization-related syndromes and partial seizures is the result of age distribution of the study.

Prevalence of adult epilepsy in Estonia

Epidemiological data about epilepsy from central and eastern Europe is scarce and results are controversial. The aim of this study was to estimate the main prevalence-related characteristics of active epilepsy in an adult population in Estonia. Review of all databases and lists related to epilepsy in Tartu supplemented by re-examination of patients to identify all persons with active epilepsy aged >/=20 years on January 1, 1997. Special attention was paid to the extensive adoption of definitions and criteria proposed by ILAE guidelines for epidemiologic studies. Both, crude and age-adjusted (to the 1970 US population) prevalence rates were 5.3 per 1000. The age-specific rates were constant in age groups 30-69 years and declined in the oldest age groups. Of the seizure types, partial seizures had highest rates, over half were secondarily generalized seizures. The largest syndromic categories were localization-related symptomatic and cryptogenic epilepsies. Risk factors for epilepsy were identified in 39.6% cases. Some 22% of all subjects did not take antiepileptic medication. Prevalence of active epilepsy and other prevalence-related characteristics in the adult population of Tartu was comparable to those reported from the developed countries. The predominance of localization-related syndromes and partial seizures is due to the age distribution of the study.

Antiepileptic drug withdrawal: literature review

Of patients with epilepsy, 60% to 70% achieve control with antiepileptic medication. Antiepileptic drugs may be associated with unwanted adverse effects, inconvenience, and cost. Remission may occur in some patients, raising the issue of whether continued treatment is necessary. Identifying patients from whom treatment can be withdrawn successfully would be beneficial on many levels, but selecting patients may be difficult. Several published antiepileptic drug withdrawal studies show variable rates of success, with relapse rates ranging from 12% to 63%. Several prognostic factors help identify patients who may be amenable to antiepileptic drug withdrawal. The results and limitations described in the antiepileptic drug withdrawal literature, prognostic factors, and general guidelines for antiepileptic drug withdrawal are presented in this article.

Nonsymptomatic generalized epilepsy in children younger than six years: excellent prognosis, but classification should be reconsidered after follow-up: the Dutch Study of Epilepsy in Childhood

PURPOSE

To assess the prognosis and the accuracy of the epilepsy classification in young children with nonsymptomatic generalized epilepsy.

METHODS

Of the cohort of the Dutch Study of Epilepsy in Childhood (n = 466), all children younger than 6 years with a diagnosis of idiopathic (IGE) or cryptogenic (CGE) generalized epilepsy either at intake (n = 108) and/or after 2 years of follow-up (n = 102) were included. The number of reclassifications after 2 years was determined, and the reasons for reclassification were analyzed. All children receiving a diagnosis of IGE or CGE at 2 years were followed up for 5 years to study their outcome in terms of terminal remission (TR). Data on their level of intellectual functioning were collected at the start of this analysis.

RESULTS

The epilepsy syndrome was reclassified in 17 children. In 14 of them, the seizure type also was reclassified, and in three, the course of the epilepsy determined the new epilepsy type. Two other children had a reclassification of their seizure types without a change of the epilepsy type. Many children were categorized as having IGE not otherwise specified. In all probability, this is a heterogeneous group, containing patients with various epilepsy syndromes, with generalized tonic-clonic seizures as a common hallmark. Of the 102 children with IGE or CGE at 2 years of follow-up, 75% had a TR of >6 months after 2 years, and 85% a TR of >or=1 year after 5 years.

CONCLUSIONS

In a fair proportion of children with nonsymptomatic generalized epilepsy in this age group, it is not possible to classify firmly the epilepsy and/or the seizures immediately after the intake. Instead, they are reclassified during the course of the disease. This and the apparent heterogeneity of the category IGE not otherwise specified point to inherent drawbacks of the current International League Against Epilepsy (ILAE) classification of epilepsy and epileptic syndromes. The prognosis of IGE at this young age is generally excellent.

Genetic abnormalities underlying familial epilepsy syndromes

Genetic defects have been recently identified in certain inherited epilepsy syndromes in which the phenotypes are similar to common idiopathic epilepsies. Mutations in the neuronal nicotinic acetylcholine receptor 4 and 2 subunit genes have been detected in families with autosomal dominant nocturnal frontal lobe epilepsy. Both receptors are components of neuronal acetylcholine receptor, a ligand-gated ion channel in the brain. Furthermore, mutations of two K+-channel genes were also identified as the underlying genetic abnormalities of benign familial neonatal convulsions. Mutations in the voltage-gated Na+-channel 1, 2 and 1 and the gamma aminobutyric acid (GABAA) receptor 2 subunit genes were found as a cause of generalized epilepsy with febrile seizures plus, a clinical subset of febrile convulsions. Na+-channels, GABAA receptor and their auxiliaries may be involved in the pathogenesis of this subtype and even in simple febrile convulsions. Mutation of a voltage-gated K+-channel gene can cause partial seizures associated with periodic ataxia type 1 and some forms of juvenile myoclonic epilepsy and idiopathic generalized epilepsy can result from mutations of a Ca2+-channel. This line of evidence suggests the involvement of channels expressed in the brain in the pathogenesis of certain types of epilepsy. Our working hypothesis is to view certain idiopathic epilepsies as disorders of ion channels, i.e. 'channelopathies'. Such hypothesis should provide a new insight to our understanding of the genetic background of epilepsy.

Syndromic diagnosis at the epilepsy clinic: role of MRI in lobar epilepsies

PURPOSE

Magnetic resonance imaging (MRI) is an essential diagnostic tool for the management of epilepsy at modern epilepsy clinics. This study was conducted to incorporate MRI features into the international classification of epilepsies and epilepsy syndromes (ICEES) proposed by the International League Against Epilepsy (ILAE).

METHODS

Three hundred consecutive patients newly registered in the Yonsei Epilepsy Clinic underwent stepwise classifications based on clinical features, clinical EEG, and clinical EEG-MRI correlations. The patients were required to have epilepsy and have undergone both EEG and MRI for inclusion in the study. Interictal epileptiform discharges (IEDs) in the EEG were divided into lobar, multilobar, and generalized. MRI lesions were divided into lobar and multilobar lesions. Lobar epilepsies (LEs) were divided into temporal, frontal, parietal, occipital, rolandic, temporoparietooccipital junctional, multilobar, and nonlocalized LEs.

RESULTS

Two hundred forty-nine patients satisfied the inclusion criteria. In the first-step diagnosis, 190 patients were classified as having localization-related epilepsy; 24 patients, generalized epilepsy; 34 patients, undetermined epilepsy; and one patient, a special syndrome. EEG revealed IEDs in 124 (50%) patients, and the second-step diagnosis changed the diagnostic categories of 79 (32%) patients. MRI detected lesions in 106 (43%) patients, and the third-step diagnosis changed the diagnostic categories of 30 (12%) patients. The nonspecific diagnostic categories of ICEES decreased from 49% to 37% and then to 29%, as diagnosis progressed from steps one to three. In cases of LE, MRI was superior to EEG in its clinical correlation. Additionally, the diagnostic precision in temporal lobe epilepsy was far better than that for other LEs.

CONCLUSIONS

The impact of MRI on ICEES was only modest in terms of changing diagnostic categories, although MRI provided a structural substrate for epilepsy in 38% of patients with negative EEGs. In LE, MRI was as sensitive as EEG, and its clinical correlation was superior to that of EEG, which strongly supports the rationale of incorporating MRI into ICEES.

The costs of epilepsy in Italy: a prospective cost-of-illness study in referral patients with disease of different severity

PURPOSE

[corrected] Epilepsy poses a considerable economic burden on society. However, information is insufficient on the comparative costs of different disease varieties. The purpose of this study was to compare the direct costs of epilepsy in referral patients with disease of different severity and duration.

METHODS

Patients with newly diagnosed epilepsy (NDE), seizure remission (SR), occasional seizures (OS), frequent non-drug-resistant (NDR) and drug-resistant (DR) seizures, and surgical candidates (SC) from 14 epilepsy centers were the target population. All patients were followed prospectively for 12 months and all medical and paramedical contacts for diagnostic and therapeutic services were noted with details, using ad-hoc diaries and semistructured questionnaires.

RESULTS

The study population comprised 525 consecutive children and adults with partial (68%), generalized (25%) and undetermined epilepsy (4%) as follows: NDE 70; SR 131; OS 108; NDR 101; DR 107; SC 8. Ambulatory visits (mean 2.8 per patient per year) were the leading service in all groups, followed by EEG recordings (1.8) and biochemical assays (1.1). At entry, the commonest drugs were carbamazepine (50%), valproate (37%), phenobarbital (21%), vigabatrin (14%) and lamotrigine (11%). New antiepileptic drugs (AED) were used increasingly with the severity of the disease. The total annual costs varied significantly across groups: 3945 Euro (SC), 2198 Euro (DR), 1626 Euro (NDR), 1002 Euro (NDE), 558 Euro (OS), 412 Euro (SR). The main item of expenditure was hospital stay (including day-hospital), followed by drug treatment and outpatient visits. The costs of outpatient services, hospital services and drugs varied significantly across groups.

CONCLUSIONS

The direct costs of epilepsy vary significantly depending on the severity of the disease and the response to treatment. Hospital admissions and drugs are the commonest items of expenditure.

The international classification of the epilepsies and epileptic syndromes. An algorithm for its use in clinical practice

An algorithm has been structured as a guided reading of the international league against epilepsy (ILAE) syndromic classification to be used in clinical practice by less experienced physicians in newly diagnosed patients. The algorithm followed the original structure of the classification, which identifies major syndromic groups, subgroups, and specific syndromes. Validation required two raters, a resident and a board-certified neurologist, to apply the algorithm with different techniques (direct or recorded interview, medical record consultation) to 19 children and 18 adults with epilepsy with information available at the time of diagnosis. The two raters' diagnoses were compared with those of the caring physicians, and cases where disagreement arose were discussed in conference to achieve consensus. The kappa statistic was used as a measure of inter-rater agreement. Caring physicians and both raters agreed in 51% of cases. Substantial agreement (kappa = 0.75) was obtained between the resident and the neurologist on major diagnostic groups and subgroups, mostly in adults. Agreement with the caring physician was slightly more satisfactory for the resident (kappa=0.67) than for the neurologist (kappa = 0.60). Agreement was better with direct or indirect interview than with record consultation, and improved further after discussion. Agreement was obtained after discussion in 32% of cases, in some of which the caring physician agreed on the resident's diagnosis. Agreement was less satisfactory for specific syndromes. On this basis, an algorithm of the ILAE classification is a fairly reliable instrument only for making a broad syndromic classification of epilepsy at the time of diagnosis. The limits of the algorithm tend mostly to reflect the intrinsic limitations of the classification itself.

Epidemiology of temporal lobe epilepsy

To fulfill its task of informed clinical decision making and resource allocation, epidemiological studies in epilepsy must adhere to a series of methodological standards. These are reviewed. Because seizure and epilepsy classification systems may be viewed as extensions of the diagnosis, they have direct implications in the acquisition and interpretation of epidemiologic data. The International League Against Epilepsy (ILAE) classification systems are analyzed in this light. Finally, the lack of Canadian epidemiological studies is addressed, and the relevance and potential of Canadian epidemiological data in epilepsy is discussed.

Incidence of epileptic syndromes in Rochester, Minnesota: 1980-1984

PURPOSE

To determine the incidence and the distribution of epileptic syndromes in a well-defined population.

METHODS

By using the records-linkage system of the Rochester Epidemiology Project, we screened all the residents of Rochester, Minnesota, who received a diagnosis of seizures, convulsions, or epilepsy from 1980 through 1984. One hundred fifty-seven residents with incident epilepsy (recurrent unprovoked seizures) were classified by using the International League Against Epilepsy (ILAE) Classification of the Epilepsies and Epileptic Syndromes. Residents with special syndromes were excluded. With a pretested algorithm, patients were classified at three levels of specification: major syndromic groups (e.g., localization-related syndromes), syndromic subgroups (e.g., idiopathic epilepsy with age-related onset), and whenever possible, individual syndromes.

RESULTS

All but one patient were classified into major syndromic groups and subgroups. The annual age-adjusted incidence per 100,000 population was 52.3 cases (34.9 for localization-related epilepsies; 7.7 for generalized epilepsies; 9.7 for undetermined epilepsies). Incidence was 0.2 for idiopathic, 17.2 for cryptogenic, 17.5 for symptomatic localization-related epilepsies, 3.7 for idiopathic, 1.7 for symptomatic or cryptogenic (age-related), and 2.3 for symptomatic (non age-related) generalized epilepsies.

CONCLUSIONS

With the exception of idiopathic epilepsies, the incidence of the major syndromic categories in our study was higher than that provided by previous population-based studies.

Continuous spike-waves during slow waves sleep. A clinical and electroencephalographic study in fifteen children

We report on the clinical and EEG features of 15 patients with the syndrome of "continuous spike waves during slow wave sleep" (CSWSS). The differential diagnosis of CSWSS includes benign epilepsy of childhood with centro-temporal spikes, and Landau-Kleffner and Lennox-Gastaut syndromes. We found normal CT and MRI features in 6 cases, periventricular leukomalacia with and without diffuse brain atrophy in 4 cases and hydrocephalus in 1 case. There was no association between specific neurological findings and CSWSS. Nine of our cases had relatively focal discharges, like some cases from the literature. The occurrence of CSWSS appears to be age-related, generally between the ages of 5 to 12 years, with a strong temporal relation to the neuropsychological deterioration in its nature, severity and prognosis. We believe that this striking disorder has been overlooked and that routine sleep EEG studies on epileptic children may disclose additional cases of CSWSS.

Newly diagnosed epilepsy in children: presentation at diagnosis

PURPOSE

The current understanding of epilepsy has changed significantly in the past 2 decades. This report presents a description of newly diagnosed childhood-onset epilepsy, with a special emphasis on epilepsy syndromes, in a large, prospectively ascertained community-based cohort evaluated and diagnosed in the mid-1990s.

METHODS

Children, aged 0 through 15 years at the time of the first seizure, were prospectively identified at the time of diagnosis of epilepsy through the practices of 16 of the 17 child neurologists in Connecticut as well as five adult neurologists and seven pediatricians from January 1993 through December 1997. Parents were interviewed, and all relevant medical records were reviewed. Classification of seizures and of epilepsy syndromes was done for each child by each of three pediatric neurologists. Discrepancies were resolved in conference.

RESULTS

A total of 613 children was recruited into the study. The median age at time of the first seizure was 5.3 years. Half the cohort was boys. Eighteen percent had a remote symptomatic etiology. Epilepsy syndromes were classifiable in all but four children, although some syndromes are, by definition, relatively nonspecific. In this childhood-onset cohort, 58.6% of the syndromes were localization related, 29.0% generalized, and 12.4% undetermined as to whether focal or generalized. Benign rolandic epilepsy occurred in 10% of the cohort. Primarily generalized syndromes accounted for 20.6%, with childhood absence being the single most common syndrome in this subgroup (12.1% of the cohort). Secondarily generalized syndromes accounted for 8.5% of the total, with infantile spasms being the most common in this grouping (3.9% of the cohort).

CONCLUSIONS

This study presents a description of childhood- and adolescent-onset epilepsy as it is diagnosed and evaluated in the 1990s in one state in the United State and based on current classification guidelines. The results should be generalizable to the rest of the country. The prognostic value of early identification of epilepsy syndromes will be determined through subsequent follow-up of this cohort.

Profile of antiepileptic pharmacotherapy in a tertiary referral center in South India: a pharmacoepidemiologic and pharmacoeconomic study

PURPOSE

To study the current pharmacotherapy practices of epilepsy and its economics in a developing country by correlating the epidemiology and economics of antiepileptic drug (AED) treatment in general epilepsy care and comprehensive epilepsy care.

METHODS

We compared the AED-use profiles, efficacy, and tolerability at entry and at last follow-up for 972 patients seen at a comprehensive epilepsy care program in South India from 1993 to 1995. The relative cost was expressed as the average percentage of the per capita gross national product (GNP/capita) each individual spent for AED treatment.

RESULTS

At entry, 562 (57.8%) subjects were receiving polytherapy; at last follow-up, 743 (76.4%) patients were receiving monotherapy, an increase of 34.3% in the use of monotherapy. One or more adverse drug reactions were reported by 28.6% of patients at entry and by 19.8% at last follow-up. The proportion of patients who were seizure free increased from 29.0 to 44.8%. Carbamazepine (CBZ) was the most frequently used AED, followed by diphenylhydantoin (DPH), valproate (VPA), and phenobarbitone (PB). The relative cost (% GNP/capita) for standard AEDs were as follows: PB, 4.4%; DPH, 7.1%; CBZ, 16.8%; and VPA, 29.5%. The average annual cost of AED treatment per patient in U.S. dollars was $64.32 at entry and $47.73 at last follow-up. Reduction in polytherapy resulted in the net annual saving of $16,128 ($16.59 per patient, or 5.4% GNP/capita).

CONCLUSIONS

The more frequent use of relatively expensive drugs like CBZ and VPA and the use of polytherapy-still quite prevalent in developing countries-has escalated the cost of AED therapy. Although in recent years AEDs have become more available in developing regions, primary and secondary care physicians have not been adequately educated about the current trends in the pharmacotherapy of epilepsy.

Is the International League against Epilepsy classification of epileptic syndromes applicable to children in Estonia?

The concept of the epileptic syndrome has had a practical and research impact on the management of patients with epilepsy. The aim of the present study was to verify the applicability of the International Classification of Epilepsies and Epileptic Syndromes in children and adolescents in Estonia. A population-based study was performed between January 1995 and December 1997 in seven counties. Only cases involving children between the ages of 1 month and 19 years with at least two unprovoked seizures were included. In all, 560 children and adolescents were referred to the Children's Hospital of the University of Tartu. A syndrome diagnosis was made in 550 (98.2%) cases: (49.4%) were localization-related (6.4% idiopathic, 18.9% symptomatic, 24.1% cryptogenic). Benign childhood epilepsy with centrotemporal spikes was present in 33 (5.9%) and childhood epilepsy with occipital paroxysms in three (0.5%); 48.4% were generalized (28.8% idiopathic, 5.7% cryptogenic or symptomatic, 14% symptomatic). Childhood absence epilepsy was present in 6.4%, juvenile absence in 2.0%, juvenile myoclonic in 0.7% and epilepsy with generalized tonic-clonic seizures on awakening in 17.7%. West syndrome was diagnosed in 1.4%, Lennox-Gastaut syndrome in 2.9% of the cases. In 0.4% of the cases it was undetermined whether seizures were focal or generalized. In 8.8% of the cases there were atypical features so they were classified as 'other symptomatic generalized epileptic syndromes not defined above' and 1.8% of the cases were unclassified. Specific neurological diseases were diagnosed in 5.0% of cases. Thus, the International Classification of Epilepsies and Epileptic Syndromes was very applicable to children and adolescents in Estonia.

The contribution of tertiary centers to the quality of the diagnosis and treatment of epilepsy. Osservatorio Regionale per l'Epilessia (OREp), Lombardy

PURPOSE

A survey was made of a network of 14 epilepsy centers in Italy to assess whether integrated diagnosis and treatment monitoring led to a more precise syndromic classification of the patients and a better response to treatment.

METHODS

Data on the diagnosis and treatment of epilepsy and the degree of seizure control were recorded in a register on 2 separate occasions, on June 30, 1990 (t0), before starting the integrated activities, and on June 30, 1992 (t1), on completion of a 2-year follow-up. Each patient's history was required to fit a specific category of the International Classification of the Epilepsies (ICE) (1). Response to treatment was classified as complete remission, occasional seizures, recurrent nonrefractory seizures, and drug-resistant epilepsy. A total of 3,469 patients of the ages of 4-80 years were enrolled.

RESULTS

At t0, 44% of cases had localization-related epilepsy, 31% generalized epilepsy, 9% undetermined epilepsy, 6% special syndromes, and 10% epileptic syndromes with atypical features. At t1, the percentages in each category were 51, 27, 7, 6, and 9%. The cases classified as "other" within each syndromic category at t0 were 11-23% and remained unchanged at t1. Patients with symptomatic localization-related epilepsies were largely recoded as symptomatic or cryptogenic epilepsies. About one-third of patients with symptomatic generalized epilepsy were recoded as localization-related epilepsies. Nine percent of patients were classified as "uncertain" epilepsies at t0, and the same proportion at t1. However, many "uncertain" diagnoses became "definite" and vice versa.

CONCLUSIONS

There was a slight increase in the proportion of patients achieving complete remission (from 13 to 28%) and untreated patients (from 10 to 17%). Nine percent of patients unresponsive to treatment at t0 had achieved remission at t1. Drug resistance was confirmed in 78% of cases and was mostly independent of the therapeutic decision. Ten percent of cases achieved remission with unchanged or simplified treatment schedules.