Connectivity of the supplementary motor area in juvenile myoclonic epilepsy and frontal lobe epilepsy

Purpose: Subtle structural abnormalities of frontal lobe gray and white matter have been described in cryptogenic frontal lobe and idiopathic generalized epilepsies. The supplementary motor area (SMA) has a role in motor control, and its involvement during frontal lobe epileptic seizures is characterized by a typical asymmetric tonic posturing. Moreover, motor networks are dysfunctional in juvenile myoclonic epilepsy (JME). We tested the hypothesis that SMA structural connectivity is altered in focal frontal lobe epilepsy (FLE) and JME compared to healthy controls. Methods: Diffusion tensor imaging (DTI) and probabilistic tractography were used to map the structural connectivity of the SMA, defined by motor functional magnetic resonance imaging (MRI), in 15 patients with JME, 36 patients with FLE, and 18 healthy controls. Key Findings: Structural connectivity of the SMA was significantly reduced in JME compared to controls (reduced fractional anisotropy and increased mean diffusivity). In FLE there was no significant difference compared to controls, and in all groups there was stronger connectivity in the left hemisphere (higher fractional anisotropy) compared to the right. There was no difference in SMA connectivity between patients with medial or lateral frontal lobe epileptic foci. Significance: Reduced white matter connectivity is the structural correlate of functional frontal lobe abnormalities in JME. In FLE, the structural connectivity of the SMA was preserved, suggesting a robust motor network that is not compromised by longstanding epilepsy involving the medial frontal lobes.     

Widespread cortical thinning in children with frontal lobe epilepsy

Purpose: Spread of seizure activity outside the frontal lobe due to cortico‐cortical connections can result in alteration in the cortex beyond the frontal lobe in children with intractable frontal lobe epilepsy (FLE). The aim of this study was to identify regions of reduced cortical thickness in children with intractable FLE. Methods: High‐resolution volumetric T₁‐weighted imaging was performed on 17 children with FLE, who were being evaluated for epilepsy surgery, and 26 age‐matched healthy controls. The cortical thickness of 12 patients with left FLE and 5 patients with right FLE was compared to controls. The clusters of cortical thinning were regressed against age of seizure onset, duration of epilepsy, seizure frequency, and number of medications. Key Findings: In children with left FLE, cortical thinning was present in the left superior frontal, paracentral, precuneus, cingulate, inferior parietal, supramarginal, postcentral, and superior temporal gyri, as well as in the right superior and middle frontal, medial orbitofrontal, supramarginal, postcentral, banks of superior temporal sulcus, and parahippocampal gyri. In children with right FLE, cortical thinning was present in the right precentral, postcentral, transverse temporal, parahippocampal, lingual, and lateral occipital gyri, as well as in the left superior frontal, inferior parietal, postcentral, superior temporal, posterior cingulate, and lingual gyri. In children with left FLE, following exclusion of one outlier, there was no significant association between age at seizure onset, duration of epilepsy, seizure frequency and number of medications with clusters of cortical thinning. In children with right FLE, age at seizure onset, duration of epilepsy, frequency of seizures, and number of medications were not associated with clusters of cortical thinning within the right and left hemispheres. Significance: Cortical changes were present in the frontal and extrafrontal cortex in children with intractable FLE. These changes may be related to spread of seizure activity, large epileptogenic zones involving both frontal and extrafrontal lobes, and development of secondary epileptogenic zones that over time lead to cortical abnormality. Further studies correlating cortical changes with neurocognitive measures are needed to determine if the cortical changes relate to cognitive function.     

Cognitive and behavioral complications of frontal lobe epilepsy in children: a review of the literature

Frontal lobe epilepsy (FLE) is considered the second most common type of the localization-related epilepsies of childhood. Still, the etiology of FLE in children, its impact on cognitive functioning and behavior, as well as the response to antiepileptic drug treatment in children has not been sufficiently studied. This review focuses on these aspects of FLE in childhood, and reveals that FLE in childhood is most often cryptogenic, and impacts on a broad range of cognitive functions. The nature and severity of cognitive deficits are highly variable, although impaired attention and executive functions are most frequent. Young age at seizure onset is the only potential risk factor for poor cognitive outcome that has been consistently reported. The behavioral disturbances associated with FLE are also highly variable, although attention deficit/hyperactivity disorder seems most frequent. In 40% of children with FLE satisfactory seizure control could not be achieved. This is a higher percentage than reported for the general population of children with epilepsy. Therefore, pediatric FLE, even if cryptogenic in nature, is frequently complicated by impairment of cognitive function, behavioral disturbances, and therapy-resistance. Given the impact of these complications, there is a need for studies of the etiology of frontal lobe epilepsy-associated cognitive and behavioral disturbances, as well as pharmacotherapy-resistance.     

Changes in extrafrontal integrity and cognition in frontal lobe epilepsy: a diffusion tensor imaging study

We used diffusion tensor imaging to characterize microstructural changes and their associations with cognition in Chinese patients with frontal lobe epilepsy (FLE). We examined 18 adult patients with FLE and 20 healthy controls. Compared with normal controls, patients with FLE had increased mean diffusivity (MD) in the right frontal lobe and decreased fractional anisotropy (FA) in both thalami. Patients with FLE also had decreased FA in the right frontal lobe that correlated with patient age at seizure onset and increased MD in the left thalamus that correlated with duration of epilepsy. Patients with FLE performed significantly worse on nearly all cognitive tasks, and there was a positive correlation between Mini-Mental Status Examination scores and FA in the left frontal lobe and the left thalamus. Our results suggest that the thalamus might be an important extrafrontal structure involved in FLE and that a longer duration of epilepsy might result in more abnormalities in the thalamus. Our results also support the hypothesis that the left frontal lobe white matter and the thalamus contribute to cognitive impairment in patients with FLE.     

Memory in frontal lobe epilepsy: An fMRI study

Purpose: Focal epilepsies are often associated with structural and functional changes that may extend beyond the area of seizure onset. In this study we investigated the functional anatomy of memory in patients with frontal lobe epilepsy (FLE), focusing on the local and remote effects of FLE on the networks supporting memory encoding. Methods: We studied 32 patients with drug‐resistant FLE and 18 controls using a functional magnetic resonance imaging (fMRI) memory encoding paradigm. Key Findings: During encoding of stimuli, patients with FLE recruited more widely distributed areas than healthy controls, in particular within the frontal lobe contralateral to the seizure onset. Normal memory performance was associated with increased recruitment of frontal areas, and conversely a poor performance was associated with an absence of this increased recruitment and decreased activation in mesial temporal lobe areas. Significance: In patients with FLE, recruitment of wider areas, particularly in the contralateral frontal lobe, appears to be an effective compensatory mechanism to maintain memory function. Impaired hippocampal activation is relatively rare and, in turn, associated with poor recognition memory.     

Social cognition in frontal lobe epilepsy

This study investigated the social cognitive functioning of patients with frontal lobe epilepsy (FLE), using a range of procedures that have shown impairments in patients following focal prefrontal brain lesions. Fourteen participants with FLE were compared with 14 healthy controls on story tests of theory of mind (ToM), faux pas appreciation, mental and physical state cartoon humor appreciation, facial emotional recognition, and the ability to perceive eye gaze expression. They were not impaired on story tests of ToM and showed only a trend toward impairment on a test of faux pas appreciation. They were impaired on humor appreciation, with both mental and physical state cartoons, and on their recognition of facial emotion and perception of eye gaze expression. Hence the patients with FLE exhibited impairments on tests of social cognition following a distinct pattern, with relatively preserved ToM, but impaired humor appreciation and ability to detect emotional expression.     

Neuropsychological performance in frontal lobe epilepsy.

The search for a special neuropsychological profile of frontal lobe epilepsy subjects (FLE) has so far led to inconclusive results. In this paper we compared the preoperative neuropsychological performance of FLE and temporal lobe epilepsy (TLE) subjects. We further investigated whether frontal lobe lesions of epileptogenic cause produce the same type of cognitive dysfunction as do tumours of the frontal lobe. Sixteen FLE subjects were compared to 16 TLE subjects as well as to a group of 10 subjects after the removal of frontal lobe tumors (TUM) and a healthy control group. A set of neuropsychological test measures routinely used for presurgical evaluation, an emotional conceptualization task and two associative learning tasks were administered. We found that subjects with frontal lobe damage were significantly impaired relative to controls on a wide range of cognitive functions independent of neurological cause. FLE subjects could hardly be discriminated from TLE subjects as both groups showed a similarly reduced level of neuropsychological performance. Our results demonstrate the devastating effect that frontal lobe epilepsy can have on cognitive functioning. Routinely used neuropsychological test measures lack the specificity to distinguish between frontal and temporal lobe epilepsy. Highly specialized measures are necessary to reveal differences.     

Theory of mind in frontal and temporal lobe epilepsy: cognitive and neural aspects

Purpose: Theory of mind (ToM) is an important prerequisite to social behavior. This study evaluated ToM in patients with temporal (TLE) or frontal lobe epilepsy (FLE) aiming to determine the cognitive aspects, severity, and pathophysiologic mechanisms of ToM impairment in focal epilepsy. Methods: One hundred thirty‐eight patients with TLE (n = 109) or FLE (n = 29) and 69 healthy subjects underwent the Faux Pas task (FPT), which evaluates the recognition and comprehension of others’ mental states, and neuropsychological tests for other cognitive functions. Key Findings: Factor analysis of all test scores yielded two ToM factors (Recognizing faux pas, FP; Excluding nonexistent FP) distinct from the Control, Language, Matching, and Praxis factors. With respect to healthy subjects, both TLE and FLE patients showed correct exclusion of nonexistent FPs but significantly lower recognition and comprehension of real FPs. FLE patients were also impaired with respect to TLE patients. In the whole patient group, schooling and group membership predicted ToM impairment. In FLE patients, the comprehension of mental states was predicted by disease duration, whereas TLE patients’ comprehension of affects and intentions was associated with early age of seizure onset and medial temporal lobe sclerosis (MTLS). Significance: Focal epilepsy impairs advanced ToM abilities. FLE may affect online performances owing to long‐lasting dysfunctions of the prefrontal areas. MTLS may provoke selective ToM deficits due to medial temporal damage, prefrontal dysfunctions, or early interference with cognitive development. Future studies are needed to determine the implications of ToM impairment on behavior and quality of life.     

Distribution of regional gray matter abnormalities in a pediatric population with temporal lobe epilepsy and correlation with neuropsychological performance

OBJECTIVE: The goals of the work described here were to determine if hippocampal and extrahippocampal atrophy in children with temporal lobe epilepsy (TLE) follows a pattern similar to that in adult patients, and to assess the clinical and neuropsychological relevance of regional brain atrophy in pediatric TLE. METHODS: Children with symptomatic TLE (n=14: 9 with mesial TLE due to hippocampal atrophy and 5 with TLE due to neocortical lesions), healthy children (n=14), and 9 adults with mesial temporal lobe epilepsy (MTLE) were compared using voxel-based morphometry (VBM) of brain magnetic resonance imaging (MRI). The children underwent a comprehensive neuropsychological battery. RESULTS: Children with MTLE with unilateral hippocampal atrophy (n=9) exhibited a significant reduction in gray matter in the hippocampus ipsilateral to the seizure origin and significant atrophy in the ipsilateral cingulate gyrus and contralateral middle frontal lobe. Children with TLE (n=14) exhibited a significant reduction in the gray matter of the ipsilateral hippocampus and parahippocampal gyrus. There was a correlation between gray matter volume in children with TLE and scores on several neuropsychological tests. Atrophy in pediatric patients with MTLE was less extensive than that in adults, and involved the hippocampi and the frontal cortex. CONCLUSIONS: Similar to adult MTLE, pediatric MTLE is associated with hippocampal and extrahippocampal cell loss. However, children display less intense quantifiable gray matter atrophy, which affects predominantly frontal lobe areas. There was a significant association between volume of gray matter in medial temporal and frontal regions and scores on neuropsychological tests. In childhood, TLE and the concomitant cognitive/behavior disturbances are the result of a damaged neural network.     

Executive functions in children with frontal and temporal lobe epilepsy.

Even though frontal lobe epilepsy (FLE) is a relatively common seizure type, no formal psychometric studies of children with FLE have been reported. We compared 12 children with FLE and 15 children with temporal lobe epilepsy (TLE) on neuropsychological tests of attention, memory, executive functioning, and adaptive functioning. The results of these tests indicated that the children with FLE had deficits in planning and executive functions, whereas their verbal and nonverbal memory was intact. The opposite pattern was observed in children with TLE. Measures of executive functioning and impulse control were the best predictors of adaptive functioning. The findings suggest that children with FLE have a pattern of cognitive deficits that differs markedly from the pattern seen in children with TLE. Children with FLE have prominent deficits in executive functioning that appear to be related to poor behavioral adaptation.     

Repeated seizures induce prefrontal growth disturbance in frontal lobe epilepsy

Background

The possible consequences of seizures in the immature brain have been the subject of much conjecture. We prospectively measured frontal and prefrontal lobe volumes using three-dimensional (3D) magnetic resonance imaging (MRI)-based volumetry in patients with frontal lobe epilepsy (FLE) presenting with the same seizure semiology. The pathogenesis of repeated seizure-induced brain damage is discussed herein.

Methods

Serial changes in regional cerebral volumes were measured in two patients with FLE presenting with intractable clinical courses and cognitive impairments/behavioral problems (FLE(+)) and four FLE patients without cognitive impairments/behavioral problems (FLE(−)). Eleven normal subjects (4–13 years old) served as controls. Volumes of the frontal and prefrontal lobes were determined using a workstation, and the prefrontal-to-frontal lobe volume ratio was calculated.

Results

Frontal and prefrontal lobe volumes revealed growth disturbance in FLE(+) compared with those of FLE(−) and control subjects. In addition, prefrontal-to-frontal lobe volume ratio increased serially in FLE(−) similarly to controls, but was stagnant or decreased in FLE(+). Prefrontal growth also revealed more rapid recovery in a FLE(+) patient with shorter active seizure period.

Conclusion

These findings suggest that repeated seizures may lead to prefrontal growth disturbance. The occurrence of frequent seizures in patients with FLE may be associated with prefrontal lobe growth retardation, which relates to neuropsychological problems and ultimate neuropsychological outcome.     

Clinical, EEG, and quantitative MRI differences in pediatric frontal and temporal lobe epilepsy

OBJECTIVE: To examine the clinical, electrographic, and quantitative MRI differences between frontal lobe (FLE) and mesial temporal lobe epilepsy (MTLE) in children. METHODS: The population included children who underwent video-EEG monitoring between 1995 and 2000 who were classified as either FLE (n = 39) or MTLE (n = 17) according to the criteria of the International League Against Epilepsy. Clinical, EEG, and quantitative MRI data (including frontal cortical volumes) were compared between the two syndromes and a control group (n = 42). RESULTS: In FLE, seizures were significantly briefer, more frequent, and predominantly from sleep, and had differing motor characteristics. The rates of bilateral epileptiform interictal and ictal EEG abnormalities were significantly higher in FLE. A nonlesional MRI was significantly more common in FLE. Mean frontal cortical volume in FLE was significantly lower than MTLE and controls. Seizure freedom after surgery was lower in FLE. CONCLUSIONS: The clinical syndrome of FLE is clearly distinct from MTLE. The etiology of this disorder is unknown in the majority of cases despite extensive investigation. Because of a lack of a clearly defined etiology and frequent nonlateralizing EEG changes, few of these children are considered optimal surgical candidates. The demonstration of bilateral frontal cortical volume loss and bilateral EEG abnormalities suggests that FLE is a bilateral disease in a high proportion of patients. The outcome in those patients who were deemed surgical candidates was significantly worse than the MTLE cases.     

Unilateral frontal lobe epilepsy affects executive functions in children

Abstract Very few studies to date have investigated the neuropsychological changes detectable in children suffering from frontal lobe epilepsy (FLE). The aim of the present study was to assess the effects of FLE on cognitive and executive functions in childhood. The sample includes 17 children with a frontal epileptogenic focus (10 right and 7 left), with no evidence of anatomical brain damage. These subjects were assessed by means of a battery of tests to investigate executive functioning. The results emphasised the presence of selective impairments of frontal lobe functions without evidence of deficits in global intellectual functioning. No side-specific deficits were detected, while an earlier onset of epilepsy and the duration of the disorder, but not the seizures frequency, were found to correspond with more severe deficits in some specific frontal lobe functions.     

Altered anterior‐posterior connectivity through the arcuate fasciculus in temporal lobe epilepsy

How the interactions between cortices through a specific white matter pathway change during cognitive processing in patients with epilepsy remains unclear. Here, we used surface‐based structural connectivity analysis to examine the change in structural connectivity with Broca's area/the right Broca's homologue in the lateral temporal and inferior parietal cortices through the arcuate fasciculus (AF) in 17 patients with left temporal lobe epilepsy (TLE) compared with 17 healthy controls. Then, we investigated its functional relevance to the changes in task‐related responses and task‐modulated functional connectivity with Broca's area/the right Broca's homologue during a semantic classification task of a single word. The structural connectivity through the AF pathway and task‐modulated functional connectivity with Broca's area decreased in the left midtemporal cortex. Furthermore, task‐related response decreased in the left mid temporal cortex that overlapped with the region showing a decrease in the structural connectivity. In contrast, the region showing an increase in the structural connectivity through the AF overlapped with the regions showing an increase in task‐modulated functional connectivity in the left inferior parietal cortex. These structural and functional changes in the overlapping regions were correlated. The results suggest that the change in the structural connectivity through the left frontal–temporal AF pathway underlies the altered functional networks between the frontal and temporal cortices during the language‐related processing in patients with left TLE. The left frontal–parietal AF pathway might be employed to connect anterior and posterior brain regions during language processing and compensate for the compromised left frontal–temporal AF pathway. Hum Brain Mapp 37:4425–4438, 2016. © 2016 Wiley Periodicals, Inc.     

Patterns of altered functional connectivity in mesial temporal lobe epilepsy

Purpose: In mesial temporal lobe epilepsy (MTLE) the epileptogenic area is confined to the mesial temporal lobe, but other cortical and subcortical areas are also affected and cognitive and psychiatric impairments are usually documented. Functional connectivity methods are based on the correlation of the blood oxygen level dependent (BOLD) signal between brain regions, which exhibit consistent and reproducible functional networks from resting state data. The aim of this study is to compare functional connectivity of patients with MTLE during the interictal period with healthy subjects. We hypothesize that patients show reduced functional connectivity compared to controls, the interest being to determine which regions show this reduction. Methods: We selected electroencephalography–functional magnetic resonance imaging (EEG‐fMRI) resting state data without EEG spikes from 16 patients with right and 7 patients with left MTLE. EEG‐fMRI resting state data of 23 healthy subjects matched for age, sex, and manual preference were selected as controls. Four volumes of interest in the left and right amygdalae and hippocampi (LA, RA, LH, and RH) were manually segmented in the anatomic MRI of each subject. The averaged BOLD time course within each volume of interest was used to detect brain regions with BOLD signal correlated with it. Group differences between patients and controls were estimated. Key Findings: In patients with right MTLE, group difference functional connectivity maps (RMTLE ? controls) showed for RA and RH decreased connectivity with the brain areas of the default mode network (DMN), the ventromesial limbic prefrontal regions, and contralateral mesial temporal structures; and for LA and LH, decreased connectivity with DMN and contralateral hippocampus. Additional decreased connectivity was found between LA and pons and between LH and ventromesial limbic prefrontal structures. In patients with left MTLE, functional connectivity maps (LMTLE ? controls) showed for LA and LH decreased connectivity with DMN, contralateral hippocampus, and bilateral ventromesial limbic prefrontal regions; no change in connectivity was detected for RA; and for RH, there was decreased connectivity with DMN, bilateral ventromesial limbic prefrontal regions, and contralateral amygdala and hippocampus. Significance: In unilateral MTLE, amygdala and hippocampus on the affected and to a lesser extent on the healthy side are less connected, and are also less connected with the dopaminergic mesolimbic and the DMNs. Changes in functional connectivity between mesial temporal lobe structures and these structures may explain cognitive and psychiatric impairments often found in patients with MTLE.     

Nonlesional frontal lobe epilepsy (FLE) of childhood: clinical presentation, response to treatment and comorbidity

RATIONALE: Few studies have looked at long-term epileptic and cognitive outcome of frontal lobe epilepsy (FLE) in children. Most are limited by inclusion of lesional and nonlesional patients. GOAL: To define the epileptic and functional outcome of children with nonlesional FLE. METHODS: We reviewed medical records and neuropsychological evaluations of patients with nonlesional FLE diagnosed between 1994 and 2004. We included children with either focal or regional frontal EEG and/or functional imaging abnormalities. We reviewed their charts for seizure and neuropsychological outcome. RESULTS: We included 21 children. Twelve (57.1%) presented with daily seizures. Seizures were nocturnal in 8 of 21, secondarily generalized in 6 of 21, adversive in 5 of 21, and focal motor in 6 of 21. Although, initial seizure control was poor in 14 of 21, long-term control was achieved in 10 of 21 after 14.6+/-22.3 months. Early development was normal in 12 of 21 but at later formal neuropsychological evaluation only 3 of 12 still had a normal profile. The majority of children had learning difficulties requiring special education prior to seizure onset (6 of 10). A clearly defined regression after seizure onset was observed in three children. The majority exhibited attention deficit and hyperactivity or impulsivity (14 of 21), behavioral problems (8 of 21), and cognitive impairments (10 of 21). Early seizure control was associated with a better cognitive outcome. CONCLUSION: Nonlesional FLE is associated with poor seizure and behavioral outcomes. Whether this is secondary to MRI-silent developmental lesions or to the progressive repercussion of seizures on frontal lobe functions remains uncertain. A prospective study with early neuropsychological assessment could help confirm the latter.     

Neuropsychological profiles and outcomes in children with new onset frontal lobe epilepsy

Frontal lobe epilepsy (FLE) is the second most frequent type of localization-related epilepsy, and it may impact neurocognitive functioning with high variability. The prevalence of neurocognitive impairment in affected children remains poorly defined.This report outlines the neuropsychological profiles and outcomes in children with new onset FLE, and the impact of epilepsy-related factors, such as seizure frequency and antiepileptic drug (AED) load, on the neurocognitive development.Twenty-three consecutive children (15 males and 8 females) with newly diagnosed cryptogenic FLE were enrolled; median age at epilepsy onset was 7 years (6–9.6 years). They underwent clinical and laboratory evaluation and neuropsychological assessment before starting AED treatment (time 0) and after one year of treatment (time 1).Twenty age-matched patients affected by idiopathic generalized epilepsy (10 male and 10 females) and eighteen age-matched healthy subjects (9 males and 9 females) were enrolled as controls and underwent the same assessment.All patients with FLE showed a significant difference in almost all assessed cognitive domains compared with controls, mainly in frontal functions and memory. At time 1, patients were divided into two groups according to epilepsy-related factors: group 1 (9 patients) with persisting seizures despite AED polytherapy, and group 2 (14 patients) with good seizure control in monotherapy. A significant difference was highlighted in almost all subtests in group 1 compared with group 2, both at time 0 and at time 1.In children with FLE showing a broad range of neurocognitive impairments, the epilepsy-related factors mostly related to a worse neurocognitive outcome are poor seizure control and the use of AED polytherapy, suggesting that epileptic discharges may have a negative impact on the functioning of the involved cerebral regions.     

难治性癫痫患者楔前叶功能连接的静息态功能磁共振成像研究

目的应用静息态功能磁共振成像(rs-f MRI)探讨难治性癫痫患者楔前叶与全脑功能连接的改变及其意义。方法对23例难治性癫痫患者(癫痫组)及23名健康人(对照组)进行rs-f MRI检查,采集数据后采用功能连接的方法,分别计算以左侧楔前叶和右侧楔前叶为感兴趣区与全脑的功能连接,运用双样本t检验的统计学方法发现两组的显著性差异并进行分析。结果癫痫组左侧楔前叶与双侧顶下小叶、双侧岛叶、右侧缘上回、右侧额中回和双侧额下回的功能连接较对照组减弱(均P0.05);癫痫组左侧楔前叶与双侧海马旁回、双侧额上回、左侧后扣带回的功能连接较对照组增强(均P0.05)。癫痫组右侧楔前叶与左侧顶下小叶、右侧缘上回、右侧额中回、右侧额下回的功能连接较对照组减弱(均P0.05);癫痫组右侧楔前叶与双侧楔叶、左侧后扣带回的功能连接较对照组增强(均P0.05)。结论难治性癫痫患者静息状态下楔前叶与全脑的功能连接存在异常,"默认网络"功能的抑制可能是癫痫患者意识及认知等功能损害的重要原因。     

Connectivity disruptions in resting-state functional brain networks in children with temporal lobe epilepsy

Functional resting-state connectivity has been shown to be altered in certain adult epilepsy populations, but few connectivity studies have been performed on pediatric epilepsy patients. Here functional connectivity was measured in pediatric, non-lesional temporal lobe epilepsy patients with normal intelligence and compared with that in age and gender-matched healthy controls using the independent component analysis method. We hypothesized that children with non-lesional temporal lobe epilepsy have disrupted functional connectivity within resting-state networks. Significant differences were demonstrated between the two groups, pointing to a decrease in connectivity. When the results were analyzed according to the interictal electroencephalogram findings, however, the connectivity disruptions were seen in different networks. In addition, increased connectivity and abnormally anti-correlated thalamic activity was detected only in the patients with abnormal electroencephalograms. In summary, connectivity disruptions are already to be seen at an early stage of epilepsy, and epileptiform activity seems to affect connectivity differently. The results indicate that interictal epileptiform activity may lead to reorganization of the resting-state brain networks, but further studies would be needed in order to understand the pathophysiology behind this phenomenon.     

Attention, memory, and behavioral adjustment in children with frontal lobe epilepsy

To explore whether attention, memory, and behavior would be more affected in children with frontal lobe epilepsy than in children with other types of epilepsy, we compared 16 children with frontal lobe epilepsy (FLE), 8 with temporal lobe epilepsy (TLE), and 8 with generalized absence (GEA) seizures on the Performance Speed (PS) and Freedom of Distraction (FD) indices of the WISC-III, the Continuous Performance Test (CPT), the California Verbal Learning Test (CVLT), and Rey-Osterrieth Complex Figure (ROCF). Parents completed Achenbach's Child Behavior Check List. Children with FLE scored significantly lower than the other two groups on the PS and CPT. On the CVLT they made more intrusion errors and were more prone to interference. Furthermore, they had more difficulties copying and recalling the ROCF. Behavior profiles revealed greater attention problems in this group. This may put children with FLE at greater risk of developing school problems than children with TLE and GEA.