Approximately 10% of children meet criteria for IE early in the course of their epilepsy. Cryptogenic/symptomatic generalized syndromes carry the highest risk and idiopathic syndromes the lowest. Half of IE occurs in children with nonidiopathic localization-related syndromes. Initial seizure frequency is highly predictive of IE. By contrast, absolute number of seizures and unprovoked or febrile status epilepticus are not.

SUMMARYPurpose: To determine the frequency and determinants of subnormal global cognitive function in a representative, community-based sample of children prospectively identified at the time of initial diagnosis of epilepsy. Methods: In children enrolled with newly diagnosed epilepsy and followed a median of 10.5 years, level of cognitive function (within normal, borderline, mild, moderate to severe mental retardation (MR), neurologically devastated, and impaired but not further classified (NFC)) was determined based upon neurologists' and school records, repeated parental interviews, and, in over half the participants, standardized neuropsychological testing. For multivariable analyses, subnormal cognitive function was designated as consistent with a full scale IQ < 80. Results: Global cognitive function was considered within normal, N = 451 (73.6%), borderline, N = 31 (5.1%), mild MR, N = 21 (3.4%), more severe MR, N = 45 (7.3%), devastated, N = 29 (4.7%), and impaired-NFC, N = 36 (5.9%). Age at onset <5 years, symptomatic etiology, epileptic encephalopathy, remission status and current AED treatment were each strongly associated with level of cognitive function (all p-values <0.0001). In a multivariable logistic regression model, all variables except remission status independently contributed to subnormal global cognitive function. Discussion: Evidence of subnormal global cognitive function is apparent in approximately one of four children with epilepsy. Young age at onset, symptomatic cause, epileptic encephalopathy, and continued treatment, despite their strong intercorrelations, are independently associated with this outcome. KEY WORDS: Cognition, Neuropsychology, Children, Epilepsy.Epilepsy is associated with significant cognitive comorbidity (Lhatoo & Sander, 2001) although the frequency of such comorbidity in people with epilepsy in the general population is often hard to determine. This association between epilepsy and cognitive comorbidity is due to a number of factors including the underlying causes of and risk factors for epilepsy which themselves may be associated (Hack et al., 1996;Pinto-Martin et al., 1999;Wood et al., 2000). The association between mental retardation (MR) and epilepsy has been well described in the literature (Curatolo et al., 1995;Eriksson et al., 1998). The effects of chronic seizures on brain development, structure and function (Holmes, 2001;Fuerst et al., 2003;Hermann et al., 2006); the medication used to treat seizures (Meador, 1994(Meador, , 2006; and possibly an independent effect of the physiological disturbances that predispose the brain to seizures in the first place (Berg et al., 2005) may all contribute to cognitive morbidity in people with epilepsy. Many of these factors are strongly intercorrelated. The overall burden of cognitive co-morbidity in people with epilepsy and the independent contribution of 608 609 Cognitive Function in Epilepsy each of these factors to abnormal cognitive function have not, to our knowledge, been clearly delineated.In the context of l...

Summary: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 childhoodand 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.

Intractable epilepsy may be delayed, especially in focal epilepsy. It often is preceded by a quiescent period, followed by further remissions. These findings help explain why surgically treatable epilepsies may take 20 years or longer before referral to surgery.

Objectives: Increasing evidence suggests that uncontrolled seizures have deleterious effects on cognition and behavior, particularly in the developing brain. Methods:In a community-based cohort, 198 children, aged Ͻ8 years with new-onset epilepsy were followed prospectively and reassessed with the Wechsler Intelligence Scales for Children, Third Edition (WISC-III) 8-9 years later. Linear regression analyses with interactions between age at onset (age) and pharmacoresistance (PR) were used to test whether earlier onset conveyed greater vulnerability to the effects of uncontrolled seizures. Full-scale IQ (FSIQ) and the 4 subdomain scores were examined. Adjustment for adaptive behavior scores in a subset was performed. A dichotomous indicator for IQ Ͻ80 or Ն80 was used to permit inclusion of children who were not tested, particularly those who were untestable.Results: FSIQ was not correlated with age. PR was associated with an 11.4 point lower FSIQ (p ϭ 0.002) and similar decrements in each WISC-III domain. There were substantial age-PR interactions for FSIQ (p ϭ 0.003) and 3 domain scores, indicating a lessening impact of PR with increasing age. The dichotomous IQ indicator was strongly correlated with age at onset in the pharmacoresistant group (p Ͻ 0.0001) and not in the non-pharmacoresistant group (p ϭ 0.61). Adjustment for adaptive behavior measured near onset did not alter the conclusions. Conclusions:Uncontrolled seizures impair cognitive function with effects being most severe in infancy and lessening with increasing age at onset. These findings further emphasize the need for early aggressive treatment and seizure control in infants and young children. Seizures and epilepsy are increasingly being recognized to have moderate to profound effects on cognitive function. There is an increasing body of literature demonstrating that, in children with refractory epilepsy who are evaluated for epilepsy surgery, earlier age at onset is associated with lower IQ or developmental scores, 1-5 and longer duration of epilepsy before surgery is negatively correlated with IQ and ability to rebound after surgery 2,4,6 . A drug treatment trial for infantile spasms reported a striking correlation between both age at onset and delay to treatment with developmental scores assessed later at age 4 years.7 These studies focused on severe epilepsy (spasms) or pharmacoresistant surgical epilepsy and by design do not allow comparisons with cognitive outcomes in well-controlled epilepsy. Consequently, they cannot directly address the separate roles of onset age vs seizures in the developing brain.In a prospective community-based study of children with epilepsy, we examined the association of cognitive scores assessed 8 -9 years after initial diagnosis and age at onset of epilepsy, pharmacoresistance, and the interaction between the two. We specifically hypothesized that the

In children with newly diagnosed epilepsy, neuroimaging reveals a small but significant number of serious abnormalities not previously suspected. Most of these children have partial seizures or focal EEG abnormalities. Neuroimaging should be considered during the evaluation of children with newly diagnosed epilepsy, especially for those with neurologic deficits or partial seizures or focal EEG abnormalities that are not part of an idiopathic localization-related epilepsy syndrome.

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The epidemiology of lesions identified by magnetic resonance imaging (MRI), along with the use of pre-surgical evaluations and surgery in childhood-onset epilepsy patients has not previously been described. In a prospectively identified community-based cohort of children enrolled from 1993 to 1997, we examined (i) the frequency of lesions identified by MRI; (ii) clinical factors associated with 'positive' MRI scans; and (iii) the utilization of comprehensive epilepsy evaluations and neurosurgery. Of the original cohort of 613 children, 518 (85%) had usable MRI scans. Eighty-two (16%) had MRI abnormalities potentially relevant to epilepsy ('positive' scans). Idiopathic epilepsy syndromes were identified in 162 (31%) of whom 3% had positive scans. The remainder had non-idiopathic epilepsy syndromes of which 22% had positive MRI findings. Multiple logistic regression analysis identified non-idiopathic epilepsy and abnormal motor-sensory (neurological) examinations as predictors of a positive MRI scan. Of the non-idiopathic patients with normal neurological exams and who were not pharmacoresistant, 10% had positive MRI scans, including four patients with gliomas. Evaluations at comprehensive epilepsy centres occurred in 54 pharmacoresistant cases. To date 5% of the imaged cohort or 8% of non-idiopathic epilepsy patients have undergone surgical procedures (including vagal nerve stimulator implantation) to treat their epilepsy (n = 22) or for tumours (n = 6) without being drug resistant. Applying our findings to the general population of children in the USA, we estimate that there will be 127/1 000 000 new cases per year of pharmacoresistant epilepsy, and 52/1 000 000 childhood-onset epilepsy patients undergoing epilepsy evaluations. In addition, approximately 27/1 000 000 will have an epilepsy-related surgical procedure. These findings support recommendations for the use of MRI in evaluating newly diagnosed paediatric epilepsy patients, especially with non-idiopathic syndromes, and provide estimates on the utilization of comprehensive evaluations and surgery.