The cognitive effects of interictal epileptiform EEG discharges and short nonconvulsive epileptic seizures

Purpose: Educational difficulties or even severe cognitive deterioration is seen in many childhood epilepsy syndromes. Many of those cognitive deficits are related directly to the brain disorder underlying the epilepsy syndrome. However, in other types of epilepsy, the epileptic seizures and/or epileptiform activity can be the dominant factor. This is especially unknown for the more “subtle” short nonconvulsive seizure types. For this reason, we analyzed a new cohort of children. Methods: A cross‐sectional study of 188 children with epilepsy. Electroencephalography (EEG)–video recordings and cognitive testing were performed simultaneously. The results of children with short nonconvulsive seizures during a 2‐h testing session were compared with all children with epilepsy without seizures during the 2‐h cognitive testing session and with controls without epilepsy. In a second analysis the cognitive effects of frequency of epileptiform EEG discharges were analyzed. Key Findings: The cognitive effects of short nonconvulsive seizures were large, ranging from 0.5 to 1 standard deviation and concerned global cognitive function, speed of central information processing, and memory function. In children without seizures during cognitive testing, the occurrence of frequent epileptiform discharges showed more subtle effects. These effects were independent from the occurrence of short nonconvulsive seizures. Significance: We concluded that although the effect is less pronounced in number of areas involved and magnitude, the type of association between frequent epileptiform activity (>1% of the time) and cognitive function in children with epilepsy is comparable to the association between short nonconvulsive seizures and cognitive function.     

Effect of Seizures and Epileptiform Discharges on Cognitive Function

Summary: Several relationships have been obtained between cognitive impairment and epilepsy-related or treatment-related factors. One of these factors is treatment-related: the central cognitive side effects of the antiepileptic drugs (AEDs). The second and third factors are disease-related factors, i.e., the effect of the seizures and underlying epileptiform discharges in the brain and the localization of the epileptogenic focus in specific areas of the brain. Although most cognitive problems have a multifactorial origin and often several factors combined are responsible for the "make-up" of a cognitive problem, we have attempted to isolate one factor: the effect of seizures and epileptiform EEG discharges on cognitive function. Several studies show the impact of ictal activity, but special attention is required for the postictal and interictal effects of epilepsy on cognitive functions. This may explain substantial cognitive impairments in children with subclinical epileptiform discharges or with infrequent subtle seizures.     

Psychiatric and Behavioural Disorders in Children with Epilepsy (ILAE Task Force Report): Subtle behavioural and cognitive manifestations of epilepsy

A subtle behavioural or cognitive manifestation of epilepsy can be defined in two ways. First, epileptiform discharges not presenting as obvious seizures may nevertheless affect cognition and/or behaviour. Second, the actual seizures may be obvious but the way they affect cognition or behaviour may not be. There is a growing body of evidence indicating that the epileptiform discharges in benign epilepsy with centrotemporal spikes can affect behaviour and cognition. The focal discharges in other forms of epilepsy can also be associated with behavioural change. The Landau‐Kleffner syndrome, the CSWS syndrome, transitory cognitive impairment and transient epileptic amnesia provide further examples of cognitive and behavioural manifestations resulting from subtle manifestations of the epilepsy. Prompt, effective antiepileptic treatment with medication or surgery can improve behaviour and cognition in at least some cases.     

Benign Myoclonic Epilepsy in Infancy (BMEI): A Longitudinal Electroclinical Study of 22 Cases

Summary:  Purpose: Benign myoclonic epilepsy in infancy (BMEI) is a nosologically well-defined entity, characterized by myoclonic seizures (MS) in normal children younger than 3 years and by a good long term prognosis. In some cases the seizures are reflex. We studied 22 cases to better define the electroclinical semeiology and evolution of the disorder.
Methods: Serial electroclinical and neuropsychological assessments, both during wakefulness and during sleep, were performed in 22 otherwise healthy children with spontaneous (17) or reflex (5) MS, recorded by video-EEG-polygraphy since clinical onset.
Results: Seizure onset was between 3 months and 4 years 10 months (50% during first year, 86% before the third year); in reflex cases onset, was earlier than the 14th month. MS recurred during wakefulness and slow sleep in all cases and during REM sleep in reflex cases. MS and related EEG discharges were synchronous or asynchronous. Often ictal EEG discharges were limited to the rolandic and vertex regions (falsely focal paroxysms). Several seizures were subtle and could have escaped recognition. Unusually frequent sleep startles were recorded mostly in reflex cases. MS were well controlled by treatment. At follow-up, between ages 3 and 19 years, four patients had occasional seizures; two had cognitive impairment and three had learning difficulties. No other seizures or cognitive deficits were observed in reflex cases.
Conclusions: Seizures associated with BMEI are rarely truly generalized and are often so subtle and related to falsely focal paroxysms that their frequency can be underestimated. The reflex form is a well-defined variant with an early onset, peculiar electroclinical features, and a good prognosis.     

Acute cognitive effects of nonconvulsive difficult-to-detect epileptic seizures and epileptiform electroencephalographic discharges

This study compares the acute cognitive effects of short nonconvulsive seizures with the effects of interictal epileptiform electroencephalographic (EEG) discharges in children. The study is a prospective, standardized, nonrandomized, and open clinical comparative study. Eligible patients were included when they had (a) unclear seizures and fluctuations in cognitive performance and (b) frequent epileptiform EEG discharges in a recent EEG. All children were assessed with EEG/video (Brainlab) simultaneously with computerized neuropsychologic testing (FePsy) assessing motor speed/alertness, mental speed/attention, and memory function. Eleven patients with short nonconvulsive seizures during cognitive testing were included and compared with 11 matched patients with interictal epileptiform EEG discharges during cognitive testing but without seizures. Patients included in both groups had a reconfirmed diagnosis of epilepsy. Cognitive performance for both groups was compared. Statistical analysis showed significant correlations between the number of seizures (during cognitive testing) and impaired alertness and between the duration of the ictal period and memory impairment. Interictal epileptiform EEG discharges do not have an additional independent effect on cognitive function. The results demonstrate the accumulating cognitive effect of seizures and illustrate that frequent seizures, even when these are short in duration and with subtle symptomatology, can have a substantial impact on daily life and can lead to state-dependent learning impairment. Alertness and short-term memory appeared to be the functions that are most vulnerable for the acute effects of seizures.     

Cognitive impairment in preschool children with epilepsy

Purpose: Studies have shown that underlying pathology and early onset of seizures are both significant factors contributing to cognitive impairment in children with epilepsy. However, there are only few studies focusing on cognitive impairment in preschool children with epilepsy. The purpose of this study was to describe the cognitive performance in a population‐based cohort of preschool children with epilepsy. The aims of the study were to determine frequency of cognitive impairment, level of cognitive functions, and epilepsy‐related factors correlating with cognitive impairment. Methods: The study group consisted of a population‐based cohort (N = 64) of preschool children (3–6 years 11 months) with active epilepsy. Medical data and results from previous psychological evaluations were reviewed retrospectively from the medical records. A logistic regression model was used for the prediction of cognitive impairment. Key Findings: Prevalence of epilepsy was 3.2 per 1,000 children. Cognitive function was considered to be within normal or borderline range for 50%, mildly retarded for 22%, and moderately to severely retarded for 28%. Cognitive impairment was related to complicated epilepsy, age at onset of epilepsy, abnormal magnetic resonance imaging (MRI), and additional neurologic problems. Age at the onset of seizures was the only significant predictor of cognitive impairment. Significance: The results concur with those of earlier studies on cognitive impairment in childhood epilepsy. Age at onset of epilepsy is also an important factor for cognitive impairment on young children with epilepsy. The results suggest that cognitive impairment is evident early in the course of epilepsy.     

Relative influence of epileptic seizures and of epilepsy syndrome on cognitive function

Cognitive impairment is frequently observed in children with epilepsy. We aimed at addressing to what extent cognitive function is affected by paroxysmal epileptiform activity with or without clinical seizures or by clinical features characteristic of the epilepsy syndrome. To this purpose, combined electroencephalographic (EEG) recording and cognitive testing (IQ and reaction times) were performed in 28 children. Frequent epileptiform EEG discharges significantly reduced reaction time, as did the occurrence of seizures during cognitive testing. Syndrome-related factors tended to affect cognitive functions as well: children with generalized epilepsy and high average seizure frequency obtained lower scores. Linear regression analysis showed that stable aspects of cognitive function, as reflected in intelligence level, are most closely related to the severity of the epilepsy syndrome (average seizure frequency), whereas transient aspects of cognitive function, such as reaction times, are related to the occurrence of epileptiform EEG discharges. This suggests that seizures have a direct effect on transient cognitive aspects, which can accumulate and result in effects on intelligence level.     

Encephalopathy with hemi-status epilepticus during sleep or hemi-continuous spikes and waves during slow sleep syndrome: A study of 21 patients

PurposeTo retrospectively analyze the electroclinical features, etiology, treatment, and prognosis of 21 patients with encephalopathy with hemi-status epilepticus during sleep (ESES) or hemi-continuous spikes and waves during slow sleep (CSWSS) syndrome.MethodsCharts of 21 patients with hemi-ESES/CSWSS syndrome followed between 1997 and 2012 were analyzed. Inclusion criteria were: (1) Focal seizures or apparently generalized seizures and focal EEG epileptiform discharges; (2) Further occurrence of atypical absences, and myoclonic, atonic, and/or generalized seizures; (3) Cognitive impairment and/or behavioral disturbances; (4) Hemi-continuous spike-and-wave discharges during slow sleep in more than 85% of non-REM sleep at onset and throughout the ESES/CSWSS period.ResultsMean follow-up from onset of hemi-ESES/CSWSS was 8 years (range, 2–15 years). Idiopathic cases were not identified. Unilateral polymicrogyria was found in 11, shunted hydrocephalus in four, a porencephalic cyst associated with polymicrogyria in three, and a thalamic lesion in three children. All started with focal seizures with or without secondary generalization. During the hemi-ESES/CSWSS period, all children developed new types of seizure, such as negative and positive myoclonus, absences, motor deterioration, cognitive impairment, and behavioral disturbances. All AED responders returned to baseline cognitive development. Seven patients were refractory to AEDs.ConclusionOur study suggests that the hemi-ESES/CSWSS syndrome has electroclinical features compatible with an epileptic encephalopathy. The most commonly used treatments were clobazam, ethosuximide, and sulthiame, alone or in combination. In refractory cases, high-dose corticosteroids were administered. Although the number of patients in this study is too low to draw definite conclusions, we consider that in children with hemi-ESES/CSWSS secondary to a unilateral lesion, surgery should be considered.     

Effect of epilepsy, seizures and epileptiform EEG discharges on cognitive function

Patients with an established diagnosis of epilepsy were included in three groups on the basis of the absence (Group 2) or presence (Group 3) of epileptiform EEG discharges or subtle seizures (Group 4) during the cognitive assessment procedure. A separate age-matched non-epileptic control group (Group 1) was formed. Twenty-five patients were included in each of the four groups. Thus, a total of 100 patients were investigated. The patients were assessed with continuous 21-channel EEG and video-monitoring, combined with cognitive testing. The results show consistently lower performance on cognitive tests for Group 4, the group with subtle seizures. The difference with the control group was significant for the intelligence subtests and for the complex information processing test (p<0.05). No transient cognitive impairment was found. The results are discussed in the light of possible factors that may be responsible for the lower test-scores in the patients of Group 4: both the ictal effects of the seizures themselves, postictal effects and the effects of the epileptiform EEG discharges may have had an impact on cognitive performance. Finally the absence of evidence for transient cognitive impairment in a group with frequent epileptiform EEG discharges is discussed in detail.     

The cognitive impact of epileptiform EEG discharges and short epileptic seizures: Relationship to characteristics of the cognitive tasks

ObjectiveWe analyzed the effect of task dimensions (information processing demand; duration of the test; input modality) on the occurrence and cognitive impact of epileptiform EEG discharges (EEDs) or subtle epileptic seizures.MethodsOne hundred ninety-nine children, aged 6–17 years, were included consecutively in a prospective standardized study. All children were assessed with EEG, which was synchronized with a computerized cognitive FePsy test system.ResultsNo association was found between the occurrence of EEDs or subtle epileptic seizures and the three task dimensions introduced in our study. The Computerized Visual Searching Task (CVST) appeared to be particularly sensitive to direct cognitive effects of EEDs. The CVST and the three memory tests—Corsi’s Block Tapping and recognition of words/figures—were sensitive to the cognitive effects of subtle epileptic seizures.ConclusionOur results do not indicate a distinctive effect of information processing demand, duration of the test, or input modality on the occurrence of EEDs or subtle epileptic seizures. Effects on the impact on cognition are found when these three factors are combined.     

Childhood diabetes and cognitive function

Although diabetes might not be typically associated with reduced intelligence in children, mild cognitive function impairment may occur if onset is before 5 years of age, or the child has recurrent hypoglycemic seizures for longer periods. Therefore, children receiving intensive insulin therapy should be closely monitored to prevent hypoglycemic seizures. Some studies have showed that the hypoglycemic effect is minimal on cognition, and may be due to hyperglycemic microvascular disease associated with diabetes. Others suggested a protective effect for hypoglycemia on developing cognitive function decrement in diabetic children. Both electronic as well as published databases were searched, and studies assessed regarding their methodology. The conclusion showed that this issue is still controversial with better evidence toward negative effects of hypoglycemia on younger age group memories, especially those exposed to cumulative hypoglycemic attacks for a longer time and intensity.     

Effects of epileptiform EEG discharges on cognitive function: is the concept of "transient cognitive impairment" still valid?

In this article we review the existing evidence on the cognitive impact of interictal epileptiform EEG discharges. Such cognitive impairment occurs exclusively in direct relation to episodes of epileptiform EEG discharges and must be distinguished from (post) ictal seizure effects and from the nonperiodic long-term "stable" interictal effects caused by the clinical syndrome or the underlying etiology. Especially in patients with short nonconvulsive seizures, characterized often by difficult-to-detect symptoms, the ictal or postictal effects may be overlooked and the resulting cognitive effects may be erroneously related to the epileptiform EEG discharges. The existing epidemiological data show that the prevalence of cognitive impairment during epileptiform EEG discharges is low. In one study 2.2% of the patients referred to a specialized epilepsy center for EEG recording showed a definite relationship between epileptiform EEG discharges and cognitive impairments ("transient cognitive impairment"). Several studies have sought to analyze to what extent cognitive impairment can be attributed to epileptiform EEG discharges among the other epilepsy factors (such as the effect of the clinical syndrome). These studies show that epileptiform EEG discharges have an additional and independent effect, but this effect is mild and limited to transient mechanistic cognitive processes (alertness, mental speed). This finding concurs with clinical studies that also reported only mild effects. In only exceptional cases are epileptiform EEG discharges the dominant factor explaining cognitive impairment. In addition, some studies have indicated that such mild effects may accumulate over time (when frequent epileptiform EEG discharges persist over years) and consequently result in effects on stable aspects of cognitive function such as educational achievement and intelligence. Hence, the clinical relevance is that early detection of cognitive effects of epileptiform EEG discharges and subsequent treatment may prevent a definite impact on cognitive and educational development. The disruptive effects of epileptiform EEG discharges on long-term potentiation, as established in animal experiments, may be one of the neurophysiological mechanisms underlying this accumulation. In conclusion the concept of "transient cognitive impairment" is still valid, but refinement of methodology has shown that a large proportion of presumed transient cognitive impairment can be attributed to subtle seizures, while interictal epileptic activity accounts for a much smaller part of the cognitive effects than previously thought. In particular cryptogenic partial epilepsies are associated with the risk of cognitive impairment. We hope that increased clinical awareness of this need for early detection will stimulate longitudinal and prospective research that eventually also will provide an answer to the questions of when and how epileptiform discharges that are not part of a seizure need to be treated.     

The relative influence of epileptic EEG discharges, short nonconvulsive seizures, and type of epilepsy on cognitive function

PURPOSE: This study addressed whether cognitive impairment in children with epilepsy is caused by disease-related stable factors, such as the type of epilepsy, or by acute effects of paroxysmal epileptic activity such as epileptic EEG discharges. We studied a nonselected group with short nonconvulsive seizures, as these seizures may elude detection and may therefore persist over a longer period. In this group, the diagnostic issue is to differentiate between the combined effects of several epilepsy-related factors on cognition. METHODS: All children were assessed with 32-channel EEG, synchronized with a computerized cognitive test system and a video-monitoring system. Recording time was 2 h. The primary inclusion criteria were unclear seizures and fluctuations in cognitive performance and/or frequent epileptic EEG discharges in a recent EEG. RESULTS: One hundred fifty-two patients met the inclusion criteria; 31 patients appeared not to have a diagnosis of epilepsy and were used as a nonepilepsy control group. Our results show that type of epilepsy has an impact on stable cognitive functions, such as educational achievement. Paroxysmal epileptic activity (acute effects of seizures and epileptic EEG discharges) affects primarily transient mechanistic cognitive processes (alertness, mental speed). CONCLUSIONS: These results suggest that the effects of paroxysmal epileptic activity on transient cognitive mechanisms may accumulate over time and consequently affect the more stable aspects of cognitive function such as educational achievement. The clinical relevance is that early detection of the cognitive impact of seizure-related activity and subsequent treatment may prevent its detrimental impact on cognitive and educational development.     

Prevalence and Characteristics of Vaccination Triggered Seizures in Dravet Syndrome in Hong Kong: A Retrospective Study

BackgroundDravet syndrome is a rare epileptic encephalopathy characterized by treatment-resistant polymorphic seizures. Seizure onset usually occurs during the first year of life, and seizures are often associated with heat-related triggering factors (e.g., fever, photosensitivity, or hot bath). It has been reported that children with Dravet syndrome often present with recurrent febrile seizures and vaccination-related seizures.MethodsWe analyzed the occurrence of vaccination-related seizures (defined as the development of a seizure within 48 hours post vaccination) in 54 patients with Dravet syndrome. Patients were divided into two groups according to whether seizures occurred within 48 hours of vaccination (i.e., vaccination-proximate group) or not (vaccination-distant group).ResultsThere was no significant difference in the vaccination-proximate group and vaccination-distant group for the presence of SCN1A mutation. In our Dravet syndrome cohort, the vaccination-proximate group consisted of 17 (31.5%) patients with Dravet syndrome. Thus vaccination-related seizures are a common triggering factor in Dravet syndrome, reported in up to one third of our patients.ConclusionVaccination-related seizures may act as the triggering factor for the onset of seizures in children with Dravet syndrome, especially before the definitive diagnosis of Dravet syndrome can be made within the first year of life. We suggest further study of guidelines and protocols for the prevention and management of vaccination-related seizures in children with recurrent febrile seizures pending a definitive diagnosis of Dravet syndrome in the first 12 months of life.     

Epileptic encephalopathies with myoclonic seizures in infants and children (severe myoclonic epilepsy and myoclonic-astatic epilepsy).

Myoclonic attacks are not characteristic of a specific syndrome. In infancy and early childhood, they are often observed in the context of syndromes that are associated with other types of seizures and with cognitive impairment but no obvious brain lesion. Characterization of the associated seizures and age of expression allows inclusion of a number of cases in two main subgroups: severe myoclonic epilepsy (SME, or Dravet syndrome) and myoclonic-astatic epilepsy (MAE). Severe myoclonic epilepsy is an epileptic encephalopathy with invariably poor outcome in which myoclonic seizures, though frequently observed, may be absent altogether in some children. Prolonged and repeated febrile and afebrile convulsive seizures starting in infancy are the main feature and are probably causally related to cognitive decline. One third of children harbor mutation of the SCN1A gene, but the genetics of SME is probably more complex than expected with simple monogenic disorders. Treatment is usually disappointing. Myoclonic-astatic epilepsy is perhaps more a conceptual category of idiopathic myoclonic epilepsy than a discrete syndrome. Childhood-onset myoclonic-astatic attacks are the characteristic seizures associated in most with episodes of nonconvulsive status and generalized tonic-clonic seizures. Outcome is unpredictable. Either remission within a few years with normal cognition or long-lasting intractability with cognitive impairment is possible. Likewise, the effectiveness of antiepileptic drugs is variable. A number of cases of myoclonic epilepsies in infancy and early childhood, however, remain unclassified, and intermediate forms between the different syndromes exist. They must be distinguished from other syndromes with frequent brief attacks and repeated falls, especially the Lennox-Gastaut syndrome. This differentiation is often difficult and may require extensive neurophysiologic studies.     

Outcome of infants with unilateral Sturge-Weber syndrome and early onset seizures

Patients with Sturge-Weber syndrome often present with seizures during the first year of life. Currently, only patients with clinically significant seizures who do not respond to medical treatment are candidates for early epileptic surgery. However, a delay of surgical treatment may result in cognitive deterioration. We studied the correlation between parameters and outcome of seizures to re-examine the criteria for early epilepsy surgery. We performed a retrospective chart review combined with telephone interviews of parents of all Israeli infants with unilateral Sturge-Weber syndrome and early onset seizures, and we examined whether age of seizure onset and seizure intensity were correlated with cognitive level and the degree of hemiparesis at follow-up. We recruited a total of 15 patients with unilateral Sturge-Weber syndrome and early onset seizures, five of whom underwent epilepsy surgery. The mean follow-up period of all the patients was 15 years: six patients had normal intelligence, four had borderline cognitive level, three had mild mental retardation and two had moderate mental retardation. Eight of the ten non-operated patients still experience seizures at follow-up. Cognitive delay was significantly correlated with seizure intensity in the early period, but not with the age of seizures onset, the degree of hemiparesis, or the presence of ongoing seizures. We conclude that high seizure intensity in young patients with Sturge-Weber syndrome is a prognostic marker for mental deterioration.     

Atonic variant of benign childhood epilepsy with centrotemporal spikes (atonic-BECTS): a distinct electro-clinical syndrome

Purpose

To describe the clinical and electroencephalographic features, treatment strategies and outcome in a series of children with the atonic variant of benign childhood epilepsy with centrotemporal spikes (atonic-BECTS).

Material and methods

Out of the 148 patients with BECTS reviewed from January 2005 to June 2010 in our Institute, there were seven (5%) with atonic-BECTS. All underwent video EEG, high-resolution magnetic resonance imaging (MRI), neuropsychological evaluation and language assessment. Their progress was followed. In addition to sodium valproate, three were treated with steroids, followed by intravenous immunoglobulin (IVIG) when the seizures relapsed while tapering or after stopping the steroids.

Results

All of the children had earlier onset (mean = 2.4 years), increased frequency and increased duration of focal seizures compared to typical BECTS. Head drop and truncal sway due to axial or axiorhizomelic atonia occurring several times per day or week was the key manifestation. The atonic seizures worsened with carbamazepine in three, clonazepam in two and clobazam in one. When the atypical seizures commenced, some children developed one or more of the following problems: hyperactivity, attention deficit, clumsy gait, and mild cognitive or language dysfunction. Three children became seizure free, one on steroids and the other two on IVIG.

Conclusions

BECTS in children with an early age of onset and frequent and prolonged seizures is more likely to evolve into atonic-BECTS. Carbamazepine and some benzodiazepines may worsen these seizures. Three children became seizure free with immunomodulatory therapy, one on steroids and the other two on IVIG, and had complete resolution of the transient motor and cognitive impairment. Atonic-BECTS needs to be differentiated from Lennox–Gastaut syndrome since it is potentially treatable and children recover with no sequel. Although all the children in this series continued to be on treatment with sodium valproate it is currently undetermined whether they would have required to do so if followed up for an extended period of time.     

The autism-epilepsy connection

Summary   The high prevalence of epilepsy in children with autism supports a neurobiologic etiology for autism. It remains unclear whether seizures and epileptiform activity on the EEG are causative or comorbid. It is also uncertain if focal epileptiform EEG abnormalities may be associated with stable cognitive impairment. Even less clear is whether these EEG abnormalities can result in the combination of language and social dysfunction seen in autistic spectrum disorders.     

Cognition and epilepsies

It is evident that in chronic epilepsy--both symptomatic and nonsymptomatic--cognitive dysfunction precedes the onset of seizures. Cognitive disorders emerge with the underlying lesion or the concomitant physiological process. The presumed additive effect of seizures has not been decisively clarified. The degree of damage may consecutively accumulate with a disease duration of more than three decades and an unfavorable course with frequent secondary generalized seizures. Long-term follow-up investigation of cognition in different epileptic syndromes is needed to address the question of their specific role in cognitive decline. Treatments successful in seizure control may however also hold cognitive risks. Additional memory impairment due to the surgical treatment of left-sided temporal lobe epilepsy ranks first among them. Cognitive side effects of antiepileptic medication may have considerable adverse effects on patients. The need of individual assessment of cognitive side effects draws increasing attention as a precondition for treatment optimized to each patient.     

The effect of seizure type and medication on cognitive and behavioral functioning in children with idiopathic epilepsy

Antiepileptic drugs have been reported to have a variety of adverse effects on behavior and performance in children with epilepsy. Previous studies investigating these side effects, however, have not controlled for the baseline status of the child (e.g. underlying neurological condition, seizure type, socioeconomic status, family variables), making it difficult to determine whether changes in function are attributable to the use of medication. We investigated the cognitive and behavioral profiles of 43 children, aged from 4 to 16 years, with new onset, idiopathic seizures. Twenty-six of these children participated in a 6-month follow-up study, and 12 in a 12-month follow-up study, investigating the effects of antiepileptic medications on psychological functioning. The children were of average intelligence (mean 1Q108) and had not previously been treated with antiepileptic medication. Children were classified as having either generalized convulsive, generalized non-convulsive (absence), simple partial, or complex partial seizures. Prior to the initiation of treatment, children with partial seizures were found to perform better than children with generalized seizures on measures of cognitive functioning. Children with convulsive seizures obtained significantly higher cognitive scores than those with non-convulsive seizures. Children with generalized non-convulsive seizures had lower cognitive scores than subjects with other types of seizure. No differences were found between groups at baseline prior to the initiation of antiepileptic medications. Analysis of subjects' performance after 6 and 12 months of antiepileptic therapy showed no significant deterioration attributable to medication. The differences in cognitive performance of the four seizure groups at baseline were not apparent at the time of follow-up. These results indicate that intrinsic and environmental variables may play a more significant role in predisposing certain children to cognitive and learning problems than do antiepileptic medications.