Mortality in Patients with a First Unprovoked Seizure

Summary:  Purpose: The mortality after a first epileptic seizure is affected by the source of cases, the intensity of the diagnostic work-up, the type and the presumed etiology of the seizure, the length of follow-up, and the modalities of data collection (retrospective vs. prospective). We review the four studies of this topic.
Methods: Four studies have been identified which focused on the mortality of the first unprovoked seizures or the first afebrile (provoked or unprovoked) seizure. These included two population-based surveys, one clinic-based community survey, and a randomized clinical trial on the treatment of the first unprovoked generalized tonic–clonic seizure.
Results: A standardized mortality ratio (SMR) of 2.3 (95% confidence interval, CI 1.5–3.3) for unprovoked first seizures was found in a retrospective cohort study in the population of Rochester, Minnesota. The SMR was higher during the first year after the seizures to progressively decrease thereafter. Acute symptomatic seizures carried the higher risk, followed by remote symptomatic seizures, while idiopathic and cryptogenic seizures carried no risk. The increased SMR found in women and in patients aged 0–19 years enrolled in the randomized trial differs from that seen in other mortality studies in epilepsy (SMR being highest in the youngest age groups) and may be a chance finding.
Conclusions: Mortality is increased in patients with a first unprovoked seizure, particularly during the first year after the seizure. This increased mortality is associated with known etiology of the seizure, and is not present when etiology is unknown.     

Incidence of Epilepsy and Unprovoked Seizures in Rochester, Minnesota: 1935–1984

Summary: The incidence of epilepsy and of all unprovoked seizures was determined for residents of Rochester, Minnesota U.S.A. from 1935 through 1984. Ageadjusted incidence of epilepsy was 44 per 100,000 personyears. Incidence in males was significantly higher than in females and was high in the first year of life but highest in persons aged ≥75years. Sixty percent of new cases had epilepsy manifested by partial seizures, and two thirds had no clearly identified antecedent. Cerebrovascular disease was the most commonly identified antecedent, accounting for 11% of cases. Neurologic deficits from birth, mental retardation and/or cerebral palsy, observed in 8% of cases, was the next most frequently identified preexisting condition. The cumulative incidence of epilepsy through age 74 years was 3.1%. The age-adjusted incidence of all unprovoked seizures was 61 per 100,000 person-years. Age-and gender-specific incidence trends were similar to those of epilepsy, but a higher proportion of cases was of unknown etiology and was characterized by generalized onset seizures. The cumulative incidence of all unprovoked seizures was 4.1% through age 74 years. With time, the incidence of epilepsy and of unprovoked seizures decreased in children and increased in the elderly.     

Incidence of epilepsy and predictive factors of epileptic and non-epileptic seizures.

PURPOSE: To estimate the incidence of unprovoked seizures (US) and epilepsy in a general population from the southern part of the Netherlands, in relation to age, sex, etiology and seizure type, and to identify predictive factors of the epileptic and non-epileptic seizures. METHODS: All patients aged > or =14 years with a first seizure or who had undiagnosed seizures before the study period were included. Patients were identified from different sources and were independently evaluated and classified by a team of neurologists. A predictive profile for the occurrence of epileptic and non-epileptic seizures was obtained by stepwise logistic regression analysis. RESULTS: The overall annual incidence was 55/100,000 and 30/100,000 for US and epilepsy, respectively. The age-specific annual incidence of US and epilepsy increased with age and reached 120/100,000 and 62/100,000 for the > or =65 years of age group, respectively. The incidence of epilepsy and US in males was higher than in females and partial seizures prevailed over generalized seizures (40 versus 9/100,000). In up to 35% of the cases with US or epilepsy, the etiology was mainly cerebrovascular disease and brain tumors. Predictors for epileptic versus non-epileptic seizures of organic origin were an epileptiform EEG pattern (OR=0.06) versus a history of hypertension (OR=2.8) or cardiovascular disease (OR=5.4). Strong predictors for seizures of non-organic origin were female sex (OR=2.2) and head injury (OR=2.4). CONCLUSIONS: The incidence of US and epilepsy (overall, and age-, sex-, seizure-specific) was similar to those reported by other developed countries. The predictive factors found in this study may assist in the early diagnosis of seizures.     

Incidence of Epilepsy in Childhood and Adolescence: A Population-Based Study in Nova Scotia from 1977 to 1985

Summary: Data from a regional EEG laboratory allowed us to identify almost all children in Nova Scotia (population 850,000) with one or more unprovoked, afebrile seizures from 1977 through 1985. We then reviewed hospital and pediatric neurology physician charts to limit cases to those with two or more definite afebrile seizures between the ages of 1 month and 16 years. In all, 693 children developed epilepsy: typical childhood absence seizures (AS) (97), either generalized tonic-clonic (GTCs) or partial seizures either secondarily generalized or not (511), and other generalized seizure types, including infantile spasms (IS) as well as myoclonic, akinetic, tonic, and atypical AS (85). The incidence of epilepsy was 118 in 100,000 for children aged < 1 year, 48 in 100,000 for those aged 1–5 years, 43 in 100,000 for those aged 6–10 years, and 21 in 100,000 for those aged 11–15 years. The incidence for each year of age between 1 and 10 years was remarkably constant (mean 46 in 100,000 ± 7 SD). Comparison of the incidence rates showed significant differences for those aged <1 year as compared with all others, and for those aged >10 years as compared with those aged 1–10 years. We conclude that the incidence of epilepsy is highest in the first year of life, plateaus in early childhood, and decreases markedly after age 10 years. The overall incidence of epilepsy in childhood is lower than that reported in previous studies.     

Seizure recurrence after a first unprovoked seizure in childhood: a prospective study

PURPOSE: To study the risk of recurrence after a first unprovoked seizure in childhood. METHODS: All consecutive patients aged less than 14 years with one or more unprovoked seizures who were attended between January 1, 1987, and June 1, 1996, were included in a prospective study. Clinical features of patients attended after a first seizure and those attended after two or more seizures were compared. Recurrence risk in both groups was estimated by Kaplan-Meier curves. Univariate and multivariate analyses of the potential predictors of recurrence risk were performed for the group of patients attended after a first seizure using the Cox proportional hazards model. RESULTS: Included in the study were 217 children. Kaplan-Meier estimate of recurrence risk was 64% at 5 years, when only patients being attended after a first epileptic seizure were included, compared with 74% when all patients were included. Significant differences in several clinical features were found between patients attended after a first seizure and those attended after two or more seizures. Univariate and multivariate analyses showed that in the overall cohort of patients attended after a first seizure, a symptomatic etiology increased the risk of recurrence, whereas a patient age of 3 to 10 years decreased this risk. In particular, the recurrence risk was 96% at 2 years for symptomatic seizures, compared with 46% for idiopathic/cryptogenic seizures. In the group of patients with idiopathic/cryptogenic seizures, an abnormal electroencephalogram and the occurrence of seizures during sleep increased the recurrence risk, whereas a patient aged 3 to 10 years reduced it. In the group of patients with symptomatic etiology, univariate analysis revealed that there was a lower recurrence risk for patients aged 3 to 10 years. This last finding was not maintained, however, in multivariate analysis. CONCLUSIONS: The recurrence risk depends on the inclusion criteria for enrolling patients. Several factors enable us to predict the recurrence risk after a first unprovoked seizure; the most important of these factors is the etiology of the seizures.     

Incidence and predictors of seizures in patients with Alzheimer's disease

PURPOSE: To determine cumulative incidence and predictors of new-onset seizures in mild Alzheimer's disease (AD) with a cohort followed prospectively. Limited information is available on the incidence of seizures, and no reports exist of seizure predictors in AD patients. METHODS: Mild AD patients were prospectively followed at 6-month intervals to estimate incidence of unprovoked seizures, compare age-specific risk of unprovoked seizures with population norms, and identify characteristics at baseline (demographics, duration and severity of AD, physical and diagnostic test findings, and comorbid medical and psychiatric conditions) influencing unprovoked seizure risk. Review of study charts and medical records supplemented coded end-point data. RESULTS: The cumulative incidence of unprovoked seizures at 7 years was nearly 8%. In all age groups, risk was increased compared with a standard population, with an 87-fold increase in the youngest group (age 50-59 years) and more than a threefold increase in the oldest group (age 85+ years). In multivariate modeling, independent predictors of unprovoked seizures were younger age [relative risk (RR), 0.89 per year increase in age; 95% confidence interval (CI), 0.82-0.97], African-American ethnic background (RR, 7.35; 95% CI, 1.42-37.98), more-severe dementia (RR, 4.15; 95% CI, 1.06-16.27), and focal epileptiform findings on electroencephalogram (EEG) (RR, 73.36; 95% CI, 1.75-3075.25). CONCLUSIONS: Seizure incidence is increased in people starting with mild-to-moderate AD. Younger individuals, African Americans, and those with more-severe disease or focal epileptiform findings on EEG were more likely to have unprovoked seizures.     

The diagnostic aid of routine EEG findings in patients presenting with a presumed first-ever unprovoked seizure

Data are available on the yield of a single EEG recording in patients with epilepsy but there is little information on EEG findings as an aid in supporting the diagnosis of an epileptic event in patients presenting with a first-ever event suspected of being an unprovoked seizure. We retrieved files of patients above the age of 15 years admitted through the emergency room during 1991-1995 with presumed first-ever unprovoked seizure. There were 91 patients (age 50+/-24; 52 males), of whom 66% had a presumed seizure of unknown origin and 34% had presumed remote symptomatic seizures. About 80% had generalized seizures (primarily or secondarily). In all the patients an EEG had been performed within 48 h of the event. Abnormal EEGs were obtained in 69%, with epileptiform activity in 21% (10% focal, 9% generalized and 2% focal and generalized), slowing in 58% (21% focal, 31% generalized and 7% focal and generalized), and both epileptiform activity and slowing in 10%. Epileptiform activity was most common in younger patients with seizures of unknown origin, compared with older individuals with symptomatic seizures (34, 38 vs. 27%, 7%, P=0.001). We conclude that following a single unprovoked presumed seizure, adults commonly exhibit abnormalities in an EEG recorded close in time to the event. The EEG is particularly helpful in supporting the epileptic nature of the event in younger patients and in those with seizures of unknown origin.     

Estimating the incidence of first unprovoked seizure and newly diagnosed epilepsy in the low-income urban community of Northern Manhattan, New York City

Purpose : To estimate the incidence and mortality associated with first unprovoked seizure or newly diagnosed epilepsy in a low-income, predominantly Hispanic community in Northern Manhattan, New York City.
Methods : We performed a population-based study to determine the incidence of first unprovoked seizure or newly diagnosed epilepsy. Participants were Northern Manhattan residents seen at area hospitals and nursing homes between 2003 and 2005. Cumulative probability of mortality and standardized mortality ratios (SMRs) were also calculated.
Results : Among 209 incident cases identified, 123 (58.9%) presented with an incident single unprovoked seizure. A total of 138 (66.0%) participants were Hispanic and 94 (45.0%) had a median household income under $15,000/year. The overall age and sex-adjusted incidence of all unprovoked seizures was 41.1 (95%CI = 35.4–46.8) per 100,000 person-years. Higher incidence was observed in low-income groups. Incidence among Hispanics was similar to that of non-Hispanic whites and non-Hispanic blacks. The cumulative probability of mortality was 17% (95%CI = 12–24%) by 3 years after diagnosis and was significantly greater in females and in those with an identified etiology. SMRs were significantly increased for all groups with respect to age, Hispanic ethnicity, middle and high income, partial seizure type, and remote symptomatic etiology. Idiopathic/cryptogenic and progressive symptomatic etiologies, low income, gender, and non-Hispanic ethnicity were not associated with a significantly increased SMR.
Conclusion : Incidence of first unprovoked seizure or newly diagnosed epilepsy did not differ by race-ethnicity. Although lower income was associated with higher incidence, higher income was associated with an increased SMR. Future research should examine reasons for differential incidence by income.     

EEG Abnormalities in Children with a First Unprovoked Seizure

Summary: We examined EEG findings from an ongoing study of 347 children with a first unprovoked seizure. EEGs were available in 321 (93%), and 135 (42%) had an abnormal EEG. EEG abnormalities included focal spikes (n = 77), generalized spike and wave discharges (n = 28), slowing (n = 43), and nonspecific abnormalities (n = 7). Abnormal EEGs were more common in children with remote symptomatic seizures (60%) than in those with idiopathic seizures (38%) (p < 0.003), more common in partial seizures (56%) than in generalized seizures (35%) (p < 0.001), and more common in children age >3 years (52%) than in younger children (12%) (p < 0.001). Records including both awake and sleep tracings were available in 148 (46%) cases. For 122 (38%) only awake tracings and for 51 (16%) only sleep tracings were available. Fifty-nine (40%) of the 148 patients with both an awake and asleep tracing had abnormal EEGs. Of 50 such EEGs with epileptiform abnormalities, 15 (30%) demonstrated the abnormality either only while awake (n = 8) or only while asleep (n = 7). Of 17 patients with EEG slowing, 8 showed slowing only in the awake tracing and 9 showed slowing in both the awake and asleep tracing. Children with even a single unprovoked seizure have a high incidence of EEG abnormalities. Obtaining a combined awake and sleep EEG significantly increases the yield of EEG abnormalities. In children with an idiopathic first seizure, EEG abnormalities are associated with an increased risk of seizure recurrence.     

Acute Symptomatic Seizure Disorders in Young Children—A Population Study in Southern Taiwan

Summary: Purpose: To determine the incidence, etiology, and prognosis of acute symptomatic seizures in children by age 3 years.
Methods: In a population-based birth cohort study of all 15,209 neonatal survivors born in Tainan City between October 1989 and December 1991, parents or caretakers of 13,493 children aged 3 years were surveyed by telephone regarding any provoked convulsive disorder, particularly acute symptomatic seizure, in the children; medical records were reviewed.
Results: Sixty-three children (39 boys, 24 girls) had acute symptomatic seizures (incidence O.46 in 100). The leading causes of acute symptomatic seizures were acute gastroenteritis, encephalitis/encephalopathy, and bacterial meningitis. Age-specific incidence was highest in the group aged 1–12 months. Intracranial hemorrhage, bacterial meningitis, and metabolic disturbance were the major causes of acute symptomatic seizures in children aged 1–12 months. Acute gastroenteritis, encephalitis/encephalopathy, and bacterial meningitis accounted for 85% of the causes in children aged 13–24 months, and gastroenteritis and encephalitislencephalopathy were the predominant causes in those aged 25–36 months. By age 5 years, subsequent unprovoked seizures developed in 14% of the survivors of acute symptomatic seizures.
Conclusions: Many acute symptomatic seizures are preventable. The risk of subsequent unprovoked seizures is determined by underlying precipitating factors. Public education regarding the danger of shaken-baby syndrome and excessive water supplement, as well as and nationwide vaccination against bacterial meningitis in young children, is necessary.     

Remission of Seizures in a Population-Based Adult Cohort with a Newly Diagnosed Unprovoked Epileptic Seizure

PURPOSE: To investigate the probability of achieving remission of seizures after a newly diagnosed unprovoked epileptic seizure in an adult population-based cohort. METHODS: 107 patients aged 17 years or older with a newly diagnosed unprovoked epileptic seizure (index seizure) in 1985 through 1987 were followed up until the date of death or to the end of 1996. The proportion of cases during follow-up that attained a 1-year, 3-year, 5-year remission was calculated by actuarial analyses. Variables for stratification were age at diagnosis, seizure type, etiology, EEG, and the occurrence of seizures within 1 year of initiation of antiepileptic drug (AED) therapy. RESULTS: Cumulative 1-, 3- and 5-year remission rates were 68, 64, and 58%. There was no statistically significant difference regarding time points of achieving a 1-year remission after epilepsy diagnosis and the subsequent probability during follow-up of attaining a 5-year remission. Having seizures within 1 year after beginning with an AED was a statistically significant predictor of never achieving 1-year remission of seizures during follow-up (refractory seizures). Other stratified variables were not statistically significant predictors. CONCLUSIONS: Seizure prognosis for the majority of patients with newly diagnosed epilepsy is good. The time required after epilepsy diagnosis to achieve a 1-year remission of seizures does not affect the probability of additionally achieving a 5-year remission. Patients with refractory seizures can be identified within a few years from diagnosis of epilepsy. These patients must be targeted early for optimization of pharmacologic treatment, possible surgery, and psychosocial intervention.     

Newly Diagnosed Unprovoked Epileptic Seizures: Presentation at Diagnosis in CAROLE Study

PURPOSE: We describe first unprovoked seizures and newly diagnosed epilepsies at initial presentation, with a special emphasis on epilepsy syndromes, in a large cohort recruited in the mid-1990s in France. METHODS: The French Foundation for Research on Epilepsy set up a network to conduct a prospective study of patients with newly diagnosed unprovoked seizures. Information was provided by 243 child or adult neurologists. Four neurologists classified each case according to the International League Against Epilepsy (ILAE) criteria. First-seizure patients and patients with previously undiagnosed seizures were compared. RESULTS: Between May 1, 1995, and June 30, 1996, 1,942 patients aged from 1 month to 95 years were identified: 926 (47.7%) with a single seizure and 1,016 (52.3%) with newly diagnosed epilepsy. All but 17 patients had EEGs. In the first-seizure and newly-diagnosed-epilepsy groups, neuroimaging studies were performed in 78.2 and 68.3% of patients, and medication prescribed in 54.1 and 89.6%, respectively. There were significant differences between the two groups with respect to age at onset and diagnosis, sex, etiology, several specific syndromes, as well as the type and presentation of initial seizure. In patients for whom the first seizure was convulsive, only sex, multiple seizures in a day or status epilepticus, and cryptogenic localization-related syndrome differed between the two groups. CONCLUSIONS: Approximately half of patients who first came to attention for an unprovoked seizure already met epidemiologic criteria for epilepsy. There were significant differences between the types of patients with a first seizure and those with newly diagnosed epilepsy. One or several seizures at diagnosis did not influence the diagnostic assessment of the patients but had a strong influence on the initiation of treatment.     

EPIMART: Prospective Incidence Study of Epileptic Seizures in Newly Referred Patients in a French Carribean Island (Martinique)

PURPOSE: To identify, in the population living in the island of Martinique, persons who had their first epileptic seizure or first came to medical attention because of an epileptic seizure. METHODS: Between May 1, 1994, and April 30, 1995, we collected all suspected cases of provoked and unprovoked epileptic seizures admitted to the hospitals or addressed to the private neurologists or pediatricians of the island. RESULTS: Three hundred nine cases were collected. Rate of initial diagnosis of provoked and nonprovoked seizures (standardized to the U.S. population): 77.7/100,000, with a bimodal distribution of the cases with age (86 in 0- to 10-year age group and 203 in patients older than 60 years). Sixty-three cases were classified as provoked seizures (incidence, 16.4/100,000). Alcohol consumption, stroke, and cranial trauma were the most frequent causes (30.1, 20.6, and 18.7%, respectively). Two hundred forty-six cases were classified as unprovoked seizures (incidence, 64.1): seizures with a stable condition, 74 cases (I, 19.3); seizures with an evolutive condition, 17 cases (I, 4.5); seizures of unknown etiology, 155 cases (I, 40.4). These figures must be considered as the minimal rate. CONCLUSIONS: The global incidence rate of newly referred persons with a diagnosis of epileptic seizures in this study is clearly higher than those observed in industrialized countries but lower than those in developing countries. The major risk factors are represented by alcohol consumption, followed by stroke, cranial trauma, and infectious diseases.     

Epilepsy in the Elderly

Summary: Purpose : The aim of this study was to evaluate the clinical characteristics of elderly patients with epilepsy.
Methods : We retrospectively reviewed the clinical records of 190 patients (104 males and 86 females) aged 60 years or older at the time of study.
Results : Epilepsies were classified as generalized in 33 patients (17.4%), partial in 145 (76.3%), and undetermined in 12 (6.3%). Twenty-nine of 33 patients with generalized epilepsy were idiopathic, whereas all patients with partial epilepsy were symptomatic. Symptomatic partial epilepsy (SPE) began at all ages (2 to 81 years). Patients with early onset (< 20 years) showed the most unfavorable course in both seizure control and social adaptability. Patients with late onset (50 years or older) had no family history of epilepsy, and half of them had a past history of ccrebrovascular disease or head injury as a presumed etiology. In patients with idiopathie generalized epilepsy (IGE), 25 of 29 had early onset, and a family history of epilepsy was found in 31%. Nineteen patients continued to have seizures after 50 years of age, albeit infrequently. Furthermore, 10 of them showed exacerbation around the age of 50.
Conclusions : Most of the late onset epilepsies were SPE with a relatively good prognosis. General belief has held that seizure outcome in IGE is favorable, but some IGE patients show an increased seizure propensity in old age.     

Short-Term Mortality After a First Epileptic Seizure: A Population-Based Study

PURPOSE: To determine the short-term mortality in a prospective incidence cohort of patients included after any kind of first afebrile epileptic seizure (i.e., provoked and unprovoked). METHODS: Information on death occurring within the first year of follow-up was collected in a cohort of 804 patients with a first seizure between March 1, 1984, and February 28, 1985, in southwest France. The variables analyzed were the etiology of seizure, cause of death, interval between seizure and death, and age of patients. RESULTS: By the end of the 1-year follow-up, there were 149 deaths among these patients as compared with 16 expected deaths [standardized mortality ratio (SMR), 9.3; 95% confidence interval (CI), 7.9-10.9]. There were no deaths in patients with idiopathic seizures. Patients with cryptogenic seizures had slightly increased mortality (SMR, 1.6; 95% CI, 0.4-4.1). Mortality was increased for patients with remote symptomatic seizures (SMR, 6.5; 95% CI, 3.8-10.5), provoked seizures (SMR, 10.1; 95% CI, 8.1-12.4), and seizures due to a progressive neurologic condition (SMR, 19.8; 95% CI, 14.0-27.3). Causes of death were underlying pathology (64%), unrelated condition (20%), unknown cause (9%), seizure-related death (6%), and one suicide. CONCLUSIONS: Early mortality clearly differed according to the etiology of the first seizure. The highest mortality was associated with provoked seizures and with seizures caused by progressive central nervous system disorders. Patients died far more often from underlying or unrelated conditions than from seizures.     

Is a first acute symptomatic seizure epilepsy? Mortality and risk for recurrent seizure

Purpose:   To compare mortality and subsequent unprovoked seizure risk in a population-based study of acute symptomatic seizure and first unprovoked seizure due to static brain lesions.
Methods:   We ascertained all first episodes of acute symptomatic seizure and unprovoked seizure due to central nervous system (CNS) infection, stroke, and traumatic brain injury (TBI). Subjects were residents of Rochester, Minnesota, identified through the Rochester Epidemiology Project's records-linkage system between 1/1/55 and 12/31/84. Information was collected on age, gender, seizure type, etiology, status epilepticus (SE), 30-day and 10-year mortality, and subsequent episodes of unprovoked seizure.
Results:   Two hundred sixty-two individuals experienced a first acute symptomatic seizure and 148 individuals experienced a first unprovoked seizure, all due to static brain lesions. Individuals with a first acute symptomatic seizure were 8.9 times more likely to die within 30 days compared to those with a first unprovoked seizure [95% confidence intervals (CI) = 3.5–22.5] after adjustment for age, gender, and SE. Among 30-day survivors, the risk of 10-year mortality did not differ. Over the 10-year period, individuals with a first acute symptomatic seizure were 80% less likely to experience a subsequent unprovoked seizure compared with individuals with a first unprovoked seizure [adjusted rate ratio (RR) = 0.2, 95% CI = 0.2–0.4].
Discussion:   The prognosis of first acute symptomatic seizures differs from that of first unprovoked seizure when the etiology is stroke, TBI, and CNS infection. Acute symptomatic seizures have a higher early mortality and a lower risk for subsequent unprovoked seizure. These differences argue against the inclusion of acute symptomatic seizures as epilepsy.     

Risk of seizure recurrence after a first unprovoked seizure: a prospective study among Jordanian children.

PURPOSE: There is wide variation in the reported recurrence rate after a first unprovoked seizure in children. We investigated the risk of recurrence after a first unprovoked seizure in Jordanian children and the risk factors associated with increased recurrence rate. METHODS: All consecutive patients aged 3 months-14 years who presented with their first unprovoked seizures between January 1997 and 2000, were included in a prospective study and followed up for 3 years for possible recurrence. Of the patients studied, there was slight male predominance (56.6%) and 55% of them were 2-9 years of age. Generalised seizures were reported in 75% and the remaining 25% had partial seizures. The duration of seizure was 1-4 minutes in 59%. Family history of epilepsy was positive in 31% and parental consanguinity in 32%. The role of these factors in increasing the risk of recurrence was also investigated. RESULTS: Two hundred sixty-five patients were included in the study and continued follow up for 3 years. Ninety-eight (37%) of them experienced seizure recurrence. Among the predictor factors for recurrence, partial seizure (P = 0.003) and positive family history (P = 0.000) were associated with a statistically significant increased risk. Sex, age, duration of seizure and consanguinity were not associated with increased risk of recurrence. CONCLUSION: Thirty-seven percent of the children studied experienced a second attack after a first unprovoked seizure over the 3 years follows up period. The risk of recurrence was significantly higher in children with a partial seizure (55%) and among those with a positive family history of epilepsy (59%). Age at first seizure, sex, duration of seizure and consanguinity were not significantly related to the risk of recurrence.     

Incidence of unprovoked seizures and epilepsy in Iceland and assessment of the epilepsy syndrome classification: a prospective study

BACKGROUND: No population-based incidence studies of epilepsy have studied syndrome classification from the outset. We prospectively studied the incidence of a single unprovoked seizure and epilepsy in the population of Iceland, and applied the syndrome classification endorsed by the International League Against Epilepsy to this population. METHODS: We used a nationwide surveillance system to prospectively identify all residents of Iceland who presented with a first diagnosis of a single unprovoked seizure or epilepsy between December 1995 and February 1999. All cases were classified by seizure type, cause or risk factors, and epilepsy syndrome. RESULTS: The mean annual incidence of first unprovoked seizures was 56.8 per 100,000 person-years, 23.5 per 100,000 person-years for single unprovoked seizures, and 33.3 per 100,000 person-years for epilepsy (recurrent unprovoked seizures). Incidence was similar in males and females. Partial seizures occurred in 40% and a putative cause was identified in 33%. Age-specific incidence was highest in the first year of life (130 per 100,000 person-years) and in those 65 years and older (110.5 per 100,000 person-years). Using strict diagnostic criteria for epilepsy syndromes, 58% of cases fell into non-informative categories. Idiopathic epilepsy syndromes were identified in 14% of all cases. INTERPRETATION: Findings are consistent with incidence studies from developed countries. Although the epilepsy syndrome classification might be useful in tertiary epilepsy centers, it has limited practicality in population studies and for use by general neurologists.     

Prospective Incidence Study and Clinical Characterization of Seizures in Newly Referred Adults

For 20 months, an extensive prospective search was made in a Swedish county to identify as many persons as possible aged greater than or equal to 17 years who had their first epileptic seizure or for the first time came to the attention of the medical community because of an epileptic seizure. The rate of initial diagnosis (first attendance rate) of non-provoked seizures was calculated as 34 in 100,000. For both sexes, the lowest age-specific incidences were found in persons aged 30-39 years. For males the highest age-specific incidence was found in the group aged 60-69 years and for females it was found in the group aged 50-59 years. The most common type of seizure was partial seizure, accounting for 60%. If seizures with rapid generalization and a known focal lesion are included, the number increases to 72%. A diagnostic delay greater than or equal to 1 year was found in 16%, mainly a patient delay. A cause for the epileptic seizure was found in 49%. A cerebrovascular disease was most common (21%). Brain tumors were found in 11% and trauma in 7%. A cause was more often identified in the older age groups. There was no significant difference between the sexes in the proportion of identified causes.     

Cause-specific mortality in adults with unprovoked seizures. A population-based incidence cohort study.

PURPOSE: To determine the cause-specific mortality relative to that expected in a population-based incidence cohort of people with unprovoked seizures. METHODS: The cohort comprises 224 inhabitants of Iceland first diagnosed as suffering from unprovoked seizures during a 5-year period from 1960 to 1964. The expected number of deaths was calculated by multiplying person-years of observation within 5-year age categories for each year from diagnosis through 1995 by cause-specific and sex-specific national death rates for those aged 20 years and above. The standardized mortality ratio (SMR) and 95% confidence intervals (95% CI) were calculated. RESULTS: All-cause mortality was increased among men (SMR 2.25, 95% CI 1.56-3.14) but not women (SMR 0.79, 95% CI 0.38-1.46). Among men, there were 8 deaths from accidents, poisoning and violence observed versus 2.82 expected (SMR 2.84, 95% CI 1.22-5.59) and 4 deaths from suicide versus 0.69 expected (SMR 5.80, 95% CI 1.56-14.84). All-cause mortality for men was still elevated after restriction of analysis to those with seizures of unknown etiology (SMR 1.73, 95% CI 1.05-2.67) with the excess deaths attributable to suicide (SMR 5.26, 95% CI 1.06-15.38). Both males and females with remote symptomatic unprovoked seizures had an increase in all-cause mortality due to excess mortality from all cancers, cerebrovascular disease and accidents. CONCLUSION: When compared with the age-, time-period- and gender-specific mortality in the general population, there is excess mortality in men but not women. The increased mortality for men is partly attributable to excess mortality from accidents and suicides.