Memory functioning in children with epilepsy: frontal lobe epilepsy, childhood absence epilepsy, and benign epilepsy with centrotemporal spikes

Neuropsychological and behavioral profiles of self-limited epileptic syndromes of childhood: a cross-syndrome comparison

Childhood epilepsy with centro-temporal spikes (CECTS), Childhood absence epilepsy (CAE) and Panayiotopoulos syndrome (PS) are some of the most common pediatric epileptic syndromes. Despite the relatively benign (self-limited) course of epilepsy, current evidence suggests that these conditions are associated with an increased risk of neuropsychological and behavioral comorbidities. This study provides a cross-epileptic syndromes' comparison reporting on the cognitive and behavioral profile of a cohort of 32 children with CECTS (n = 14), CAE (n = 10) and PS (n = 8), aged 6 to 15 years old. Frequent, although often subclinical cognitive difficulties involving attention, executive functions and academic abilities were found in children with CECTS and CAE, and to a lesser extent in PS. Internalizing symptoms (particularly anxiety) were more common in the PS group compared to CECTS and CAE based on parental reports. Correlational analysis revealed a significant correlation between phonemic fluency and seizure-free interval at the time of evaluation, suggesting a beneficial effect of epilepsy remission on this executive function measure in all the three groups. These results add to existing literature providing further detail on neuropsychological and behavioral peculiarities of children with CECTS, CAE, and PS. Moreover, the need for neuropsychological assessment as part of the standard childhood epilepsy evaluation is stressed. The results are discussed in the context of the current literature, highlighting areas of consensus and controversies related to the clinical management of these epileptic syndromes as well as directions for future research.

Neurobehavioural comorbidities of epilepsy: towards a network-based precision taxonomy

Cognitive and behavioural comorbidities are prevalent in childhood and adult epilepsies and impose a substantial human and economic burden. Over the past century, the classic approach to understanding the aetiology and course of these comorbidities has been through the prism of the medical taxonomy of epilepsy, including its causes, course, characteristics and syndromes. Although this 'lesion model' has long served as the organizing paradigm for the field, substantial challenges to this model have accumulated from diverse sources, including neuroimaging, neuropathology, neuropsychology and network science. Advances in patient stratification and phenotyping point towards a new taxonomy for the cognitive and behavioural comorbidities of epilepsy, which reflects the heterogeneity of their clinical presentation and raises the possibility of a precision medicine approach. As we discuss in this Review, these advances are informing the development of a revised aetiological paradigm that incorporates sophisticated neurobiological measures, genomics, comorbid disease, diversity and adversity, and resilience factors. We describe modifiable risk factors that could guide early identification, treatment and, ultimately, prevention of cognitive and broader neurobehavioural comorbidities in epilepsy and propose a road map to guide future research.

Executive Functions and Attention in Childhood Epilepsies: A Neuropsychological Hallmark of Dysfunction?

OBJECTIVE

Patients with epilepsy are at risk for several lifetime problems, in which neuropsychological impairments may represent an impacting factor. We evaluated the neuropsychological functions in children suffering from three main epilepsy categories. Further, we analyzed the longitudinal evolution of the neuropsychological profile over time.

METHODS

Patients undergoing neuropsychological evaluation at our Department from 2012 to 2018 were identified retrospectively. We selected patients aged 6-16 years and with at least two evaluations. Three epilepsy categories were considered: focal/structural, focal self-limited, and idiopathic generalized. Each evaluation included the same structured assessment of main neuropsychological domains. The effect of the epilepsy category, illness duration, seizure status, and medication was computed in multilevel models.

RESULTS

We identified 103 patients (focal self-limited = 27; focal/structural = 51; and idiopathic generalized = 25), for 233 evaluations. The majority of deficits were reported in attention and executive functions (>30% of patients); the results were dichotomized to obtain global indexes. Multilevel models showed a trend toward statistical significance of category of epilepsy on the global executive index and of illness duration on global attention index. Illness duration predicted the scores of executive and attention tasks, while category and medication predicted executive task performance. Focal/structural epilepsies mostly affected the executive domain, with deficits persisting over time. By contrast, an ameliorative effect of illness duration for attention was documented in all epilepsies.

CONCLUSIONS

This study offers lacking information about the evolution of deficits in time, the role of epilepsy category, and possible psychological implications for high-order cognitive skills, central in several social and academic problems.

Working Memory in Pediatric Epilepsy: A Systematic Review and Meta-Analysis

Working memory is a multicomponent system that is supported by overlapping specialized networks in the brain. Baddeley's working memory model includes four components: the phonological loop, visuo-spatial sketchpad, the central executive, and episodic buffer. The aim of this review was to establish the gravity and pattern of working memory deficits in pediatric epilepsy. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guided electronic searches. Sixty-five studies were included in the review. Meta-analyses revealed significant impairments across each working memory component: phonological loop (g = 0.739), visuo-spatial sketchpad (g = 0.521), and central executive (g = 0.560) in children with epilepsy compared to controls. The episodic buffer was not examined. The pattern of impairments, however, differed according to the site and side of seizure focus. This suggests that working memory components are differentially vulnerable to the location of seizure focus in the developing brain.

Cognitive and behavioral profiles of pediatric surgical candidates with frontal and temporal lobe epilepsy

BACKGROUND

We aimed to prospectively analyze memory and executive and social cognitive functioning in patients with drug-resistant frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE) with focal lesions and isolate the impact of intellectual ability on specific deficits.

METHODS

A neuropsychological evaluation was performed in 23 children with FLE, 22 children with TLE, and 36 healthy pediatric controls (HCs). Patients in the epilepsy groups had a range of lesions, including low-grade epilepsy-associated tumors (LEAT), focal cortical dysplasia (FCD) type II, and mesial temporal sclerosis (MS).

RESULTS

There were no significant differences between children with FLE and TLE regarding memory, executive, or social cognitive functioning. General Ability Index (GAI) was a predictor of memory, executive function, and social cognition scores and was influenced by age at onset, duration of epilepsy, and number of antiepileptic drugs (AEDs) prescribed at the time of assessment. Working Memory Index scores of patients with TLE, which measure verbal mnesic processing, were significantly lower than those of HCs and patients with TLE. The greatest differences in both clinical groups compared to HCs were recorded in cognitive executive functions, and patients with FLE had lower scores in this domain. Regarding behavioral executive functions, patients with TLE presented impaired emotional control and impulse inhibition and patients with FLE exhibited decreased flexibility.

CONCLUSION

Consistent with previous research, our findings provide further detailed evidence of small differences in cognitive performance among children with FLE and TLE. These differences emerge on analysis of the factors with which deficits are associated.

Language in childhood epilepsy: A systematic review and meta-analysis

The abnormal brain activity associated with childhood epilepsy can have an impact on the developmental trajectory of cognitive processes, like language, in this population. However, there is variation in how researchers study language ability in children with epilepsy and the findings that are reported (no differences vs. a significant difference). The current systematic review and meta-analysis uses data from 13 available studies to consider the magnitude of language differences in children with epilepsy compared to their typically developing peers. Seizure classification, age of onset, component of language measured, and instrument used to measure language were all considered as potential moderators of differences in language skill. The results indicate a significant large effect size for language deficits in children with epilepsy compared to their peers. Seizure classification partially, but not fully, accounts for the variability in effect size. In addition, effect sizes differ relative to component of language measured; effect sizes were greatest in magnitude for semantic language and verbal fluency, and minimal for syntax, but only when including all studies of children with epilepsy, regardless of seizure classification. These findings differ when considering language component in children with generalized or focal seizures only. The data reported here also indicate distinct differences in effect size depending on type of instrument used to measure one aspect of language, verbal fluency.

Neural correlates of verbal working memory in children with epilepsy with centro-temporal spikes

BACKGROUND

Previous functional magnetic resonance imaging (fMRI) studies have identified brain systems underlying different components of working memory (WM) in healthy subjects. The aim of this study was to compare the functional integrity of these neural networks in children with self-limited childhood epilepsy with centro-temporal spikes (ECTS) as compared to healthy controls, using a verbal working memory task (WMT).

METHODS

Functional MRI of WM in seventeen 6-to-13 year-old children, diagnosed with ECTS, and 17 sex- and age-matched healthy controls were conducted at 3 T. To estimate BOLD responses during the maintenance of low, medium, and high WMT loads, we used a Sternberg verbal WMT. Neuropsychological testing prior to scanning and behavioral data during scanning were also acquired.

RESULTS

Behavioral performances during WMT, in particular accuracy and response time, were poorer in children with ECTS than in controls. Increased WM load was associated with increased BOLD signal in all subjects, with significant clusters detected in frontal and parietal regions, predominantly in the left hemisphere. However, under the high load condition, patients showed reduced activation in the frontal, temporal and parietal regions as compared to controls. In brain regions where WM-triggered BOLD activation differed between groups, this activation correlated with neuropsychological performances in healthy controls but not in patients with ECTS, further suggesting WM network dysfunction in the latter.

CONCLUSION

Children with ECTS differ from healthy controls in how they control WM processes during tasks with increasing difficulty level, notably for high WM load where patients demonstrate both reduced BOLD activation and behavioral performances.

Mapping the Effect of Interictal Epileptic Activity Density During Wakefulness on Brain Functioning in Focal Childhood Epilepsies With Centrotemporal Spikes

Childhood epilepsy with centrotemporal spikes (CECTS) is the most common type of “self-limited focal epilepsies.” In its typical presentation, CECTS is a condition reflecting non-lesional cortical hyperexcitability of rolandic regions. The benign evolution of this disorder is challenged by the frequent observation of associated neuropsychological deficits and behavioral impairment. The abundance (or frequency) of interictal centrotemporal spikes (CTS) in CECTS is considered a risk factor for deficits in cognition. Herein, we captured the hemodynamic changes triggered by the CTS density measure (i.e., the number of CTS for time bin) obtained in a cohort of CECTS, studied by means of video electroencephalophy/functional MRI during quite wakefulness. We aim to demonstrate a direct influence of the diurnal CTS frequency on epileptogenic and cognitive networks of children with CECTS. A total number of 8,950 CTS (range between 27 and 801) were recorded in 23 CECTS (21 male), with a mean number of 255 CTS/patient and a mean density of CTS/30 s equal to 10,866 ± 11.46. Two independent general linear model models were created for each patient based on the effect of interest: “individual CTS” in model 1 and “CTS density” in model 2. Hemodynamic correlates of CTS density revealed the involvement of a widespread cortical–subcortical network encompassing the sensory-motor cortex, the Broca's area, the premotor cortex, the thalamus, the putamen, and red nucleus, while in the CTS event-related model, changes were limited to blood–oxygen-level-dependent (BOLD) signal increases in the sensory-motor cortices. A linear relationship was observed between the CTS density hemodynamic changes and both disease duration (positive correlation) and age (negative correlation) within the language network and the bilateral insular cortices. Our results strongly support the critical role of the CTS frequency, even during wakefulness, to interfere with the normal functioning of language brain networks.

Towards a Better Understanding of Cognitive Deficits in Absence Epilepsy: a Systematic Review and Meta-Analysis

Cognition in absence epilepsy (AE) is generally considered undisturbed. However, reports on cognitive deficits in AE in recent years have suggested otherwise. This review systematically assesses current literature on cognitive performance in children with AE. A systematic literature search was performed in Pubmed, Embase, Cochrane and Web of Science. All studies reporting on cognitive performance in children with AE were considered. In total 33 studies were eligible for inclusion. Neuropsychological tests were classified into the following domains: intelligence; executive function; attention; language; motor & sensory-perceptual examinations; visuoperceptual/visuospatial/visuoconstructional function; memory and learning; achievement. Random-effect meta-analyses were conducted by estimating the pooled mean and/or pooling the mean difference in case-control studies. Full-scale IQ in children with AE was estimated at 96.78 (95%CI:94.46–99.10) across all available studies and in case-control studies IQ was on average 8.03 (95%CI:-10.45- -5.61) lower. Verbal IQ was estimated at 97.98 (95%CI:95.80–100.16) for all studies and 9.01 (95%CI:12.11- -5.90) points lower in case-control studies. Performance IQ was estimated at 97.23 (93.24–101.22) for all available studies and 5.32 (95%CI:-8.27–2.36) points lower in case-control studies. Lower performance was most often reported in executive function (cognitive flexibility, planning, and verbal fluency) and attention (sustained, selective and divided attention). Reports on school difficulties, neurodevelopmental problems, and attentional problems were high. In conclusion, in contrast to common beliefs, lower than average neurocognitive performance was noted in multiple cognitive domains, which may influence academic and psychosocial development.

Story Learning Test: Decelerated Learning and Accelerated Forgetting in Children with Epilepsy

Introduction

Increasing interest is seen for early and late memory consolidation and accelerated forgetting, but little is known about these phenomena in children with epilepsy. The present study analysed the trajectory of learning and retention in typically developing children and children with epilepsy on a story learning test.

Methods

285 children, 126 typically developing children and 159 children with epilepsy, in ages between 4 and 10 years and Full-Scale IQs ≥ 75, were given a specifically designed story learning test (iter-sein). The learning phase included Initial reading and a Free Recall trial with 10 Questions, and up to three repetition trials with Questions. Trials of Delayed Free Recall and Questions followed after half an hour, the next day and 1 week later. With several repeated measures analyses of variance, level of performance and gains or losses over time were analysed.

Results

Age-dependent learning was seen after repetitions. On the Questions, typically developing children outperformed children with epilepsy increasingly, due to smaller gains after the second trial. Learned information was similarly preserved. Free Recall showed similar performance for both groups up to day 2. A week later, a conspicuous loss of information was observed in the children with epilepsy, whilst typically developing children retained the information. On index scores, reliable cognitive loss of information was seen in epilepsy in 24.5% of the children. Semantic neuropsychological tasks and severity measures of epilepsy were associated with level of performance.

Discussion

The results provided evidence for early decelerated learning and late accelerated forgetting in children with epilepsy.

Are frontal and temporal lobe epilepsy dissociable in their memory functioning?

There is controversy in the literature as to how dissociable frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE) are in terms of memory deficits. Some researchers have demonstrated that FLE is associated with greater executive dysfunction including working memory, whereas TLE is associated with greater memory impairment. Others have found the two groups to be comparable in memory functioning. Hence, we examined this question in children with FLE and TLE versus typically developing controls. We found most of the expected effects when the groups with focal onset epilepsy were compared to controls. Specifically, children with left TLE performed worse on verbal short-term memory/learning and long-term memory measures. In contrast, children with right TLE exhibited a more global pattern of difficulty on short-term memory/learning measures but performed worse than controls on long-term memory for faces. Children with FLE performed worse than controls on verbal working memory. Nevertheless, laterality effects were mild, as children with right and left TLE did not differ significantly from each other. Further, children with FLE did not differ from those with TLE on most measures except delayed facial recognition, where children with right TLE performed worse. In addition, attention problems and poor behavioral regulation were related to encoding problems in both the total epilepsy sample and in children with TLE specifically. Hence, our findings overall are consistent with prior studies indicating that children with TLE and FLE are commensurate in most aspects of memory impairment when compared to each other, likely related to rapid propagation between the frontal and temporal lobes, as would be expected with an excitatory lesion.

Effect of sleep quality on memory, executive function, and language performance in patients with refractory focal epilepsy and controlled epilepsy versus healthy controls - A prospective study

We aimed to evaluate the effect of sleep quality on memory, executive function, and language performance in patients with refractory focal epilepsy and controlled epilepsy and compare these with healthy individuals. We prospectively enrolled 37 adolescent and adult patients with refractory focal epilepsy (Group 1) and controlled epilepsy (Group 2) in each group. History pertaining to epilepsy and sleep were recorded, and all patients underwent overnight polysomnography. Language, memory, and executive function assessments were done using Western Aphasia Battery, Post Graduate Institute (PGI) memory scale, and battery of four executive function tests (Trail Making Test A & B, Digit symbol test, Stroop Task, and Verbal Fluency Test), respectively. Forty age- and sex-matched controls were also included in the study. Significant differences were noted in both objective and subjective sleep parameters among all the groups. On polysomnography, parameters like total sleep time, sleep efficiency, sleep latency, and rapid eye movement (REM) latency were found to be significantly worse in Group 1 as compared with Group 2. Cognitive and executive parameters were significantly impaired in Group 1. Shorter total sleep time, poorer sleep efficiency, and prolonged sleep latencies were observed to be associated with poor memory and executive function in patients with refractory epilepsy. Our study strongly suggests that sleep disturbances, mainly shorter total sleep time, poor sleep efficiency, and prolonged sleep latencies, are associated with impaired memory and executive function in patients with refractory focal epilepsy and to a lesser extent, among those with medically controlled epilepsy.

Changes in background electroencephalographic activity in benign childhood epilepsy with centrotemporal spikes after oxcarbazepine treatment: a standardized low-resolution brain electromagnetic tomography (sLORETA) study

Background

Several neuroimaging studies have reported neurophysiological alterations in patients with benign childhood epilepsy with centrotemporal spikes (BCECTS). However, reported outcomes have been inconsistent, and the progression of these changes in the brain remains unresolved. Moreover, background electroencephalography (EEG) in cases of BCECTS has not been performed often.

Methods

We investigated background EEG activity changes after six months of oxcarbazepine treatment to better understand the neurophysiological alterations and progression that occur in BCECTS. In 18 children with BCECTS, non-parametric statistical analyses using standardized low resolution brain electromagnetic tomography (sLORETA) were performed to compare the current density distribution of four frequency bands (delta, theta, alpha, and beta) between untreated and treated conditions.

Results

Background EEG activity for the delta frequency band was significantly decreased in the fronto-temporal and limbic regions of the left hemisphere after oxcarbazepine treatment (threshold log-F-ratio = ±2.729, P < 0.01). The maximum current density difference was found in the parahippocampal gyrus of the left limbic lobe (Montreal Neurological Institute coordinate [x, y, z = 25, − 20, − 10], Brodmann area 28) (log-F-ratio = 3.081, P < 0.01).

Conclusions

Our results indicate the involvement of the fronto-temporal and limbic cortices in BCECTS, and limbic lobe involvement, including the parahippocampal gyrus, was noted. In addition to evidence of the involvement of the fronto-temporal and limbic cortices in BCECTS, this study also found that an antiepileptic drug could reduce the delta frequency activity of the background EEG in these regions.

Depressive, inflammatory, and metabolic factors associated with cognitive impairment in patients with epilepsy

PURPOSE

The purpose of this study was to examine the cognitive function and depressive traits most frequently associated with the clinical assessment of patients with epilepsy and if these clinical parameters are linked to glycolipid levels and inflammatory and apoptotic markers.

METHODS

Patients with epilepsy (n = 32) and healthy subjects (n = 41) were recruited to participate in this study. Neuropsychological evaluation was performed in both groups through a battery of cognitive tests. Inflammatory markers, apoptotic factors, and deoxyribonucleic acid (DNA) damage were measured in blood samples. Additionally, the metabolic markers total cholesterol (CHO), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), and glucose (GLU) levels were analyzed.

RESULTS

Statistical analyses showed that patients with epilepsy presented decreased scores in memory, attention, language, and executive function tests compared with the control group. Analysis revealed that there was negative correlation in epilepsy for seizure duration vs. oral language (R = -0.4484, p < 0.05) and seizure duration vs. problem solving (executive functions) (R = -0.3995, p < 0.05). This was also observed when comparing depression with temporal-spatial orientation (TSO) (R = -0.39, p < 0.05). Furthermore, we observed a higher depression score in patients with epilepsy than in the healthy ones. Statistical analyses showed higher acetylcholinesterase (AChE) (p < 0.05), interleukin 1β (IL-1β, p < 0.001), and tumor necrosis factor-alpha (TNF-α) (p < 0.001) levels compared with those in the control group. Moreover, patients with epilepsy had significantly higher serum levels of caspase 3 (CASP 3) (p < 0.001) and Picogreen (p < 0.001) compared with the control subjects. Regarding the metabolic markers, higher glycolipid levels were observed in the patients with epilepsy (CHO < 0.05*, LDL < 0.0001*, TG < 0.05*, GLU p < 0.05). High-density lipoprotein levels were not significant. The patients with epilepsy had significant correlation when comparing total language with TNF-α (R = -0.4, p < 0.05), praxes with CASP 3 (R = -0.52, p < 0.01), total CHO with total language (R = -0.48, p < 0.05), TG with semantic memory (R = -0.54, p < 0.05), TG with prospective memory (R = -0.2165, p < 0.02), TG with total memory (R = -0.53, p < 0.02), and GLU with total attention (R = -0.62, p < 0.002).

CONCLUSION

This study supports the evidence of a distinct neuropsychological profile between patients with epilepsy and healthy subjects. Furthermore, our findings suggest that inflammatory pathway, glycolipid profile, and depressive factors may be associated with cognitive dysfunction in patients with epilepsy.

Identifying neural drivers of benign childhood epilepsy with centrotemporal spikes

Epilepsy is a neurological disorder characterized by abnormal electrical discharges in a group of brain cells. Benign childhood epilepsy, which affect children under the age of 12 years, has been reported to contribute to the cognitive impairment of these children, even in the absence of structural abnormalities. Functional connectivity models have been applied to provide a deeper understanding of the processes that control and regulate interictal activity of benign childhood epilepsy. These studies have shown regions of increased connectivity and activity, particularly at the epileptic zone, which is usually the central region around the sensorimotor cortex, and in the immediate regions surrounding the zone and reduced activity in distant regions, such as the frontal lobe and temporal regions. The present study was designed to identify the neural drivers involved in the initiation and propagation of epileptic activity and the causal relationships between brain regions with increased and decreased connectivity and functional activity. We used three different models to identify neural drivers and casual connectivity with dynamic causal modelling (DCM) of EEG data. All models showed that the central region, the source of the epileptic activity, is the major driver of the brain network during interictal discharges. Other regions include the temporoparietal junction and temporal pole. The central region also had influence on the frontal and contralateral hemisphere, which might explain the cognitive deficits observed in these patients.

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The epileptic source is the major driver of the brain network

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Other drivers include the temporoparietal junction and temporal pole

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Epileptic source had influence on the frontal region which might explain the cognitive deficits

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The right epileptic region drives the left hemisphere during interictal epileptic discharges

Maintenance effects of working memory intervention (Cogmed) in children with symptomatic epilepsy

PURPOSE

To extend previous research documenting the benefits of working memory (WM) intervention (Cogmed) immediately post-intervention in children with epilepsy by assessing the 3-month maintenance effects.

METHODS

Participants involved in a previous randomized clinical trial (RCT) were invited to participate if they completed Cogmed within the last 3months (n=15) and additional participants (n=13) were prospectively recruited. Standardized assessments of near-transfer effects (i.e., visual and auditory attention and WM) were completed prior to and immediately after intervention and at 3-month follow-up. An additional measure assessing the far-transfer effect of fluid reasoning was administered prior to intervention and at 3-month follow-up.

RESULTS

Participants exhibited gains in auditory and visual attention and WM immediately following intervention and gains were generally sustained at 3-month follow-up. Intervention did not improve visual-verbal WM or fluid reasoning. The clinical variables studied (i.e., age of seizure onset, seizure frequency, epilepsy duration, and overall intellectual functioning) did not elucidate reliable relationships with intervention.

CONCLUSIONS

Working memory training is possibly efficacious in improving related skills which are maintained for 3months in children with active epilepsy. No transfer to fluid reasoning was documented. Further investigation by means of a large-scale RCT which includes a placebo and both objective and subjective measures of the impact of training on daily functioning is warranted.

EEG resting state analysis of cortical sources in patients with benign epilepsy with centrotemporal spikes

Benign epilepsy with centrotemporal spikes (BECTS) is the most common idiopathic childhood epilepsy, which is often associated with developmental disorders in children. In the present study, we analyzed resting state EEG spectral changes in the sensor and source spaces in eight BECTS patients compared with nine age-matched controls. Using high-resolution scalp EEG data, we assessed statistical differences in spatial distributions of EEG power spectra and cortical sources of resting state EEG rhythms in five frequency bands: δ (0.5–3.5 Hz), θ (4–8 Hz), α (8.5–13 Hz), β₁ (13.5–20 Hz) and β₂ (20.5–30 Hz) under the eyes-closed resting state condition. To further investigate the impact of centrotemporal spikes on EEG spectra, we split the EEG data of the patient group into EEG portions with and without spikes. Source localization demonstrated the homogeneity of our population of BECTS patients with a common epileptic zone over the right centrotemporal region. Significant differences in terms of both spectral power and cortical source densities were observed between controls and patients. Patients were characterized by significantly increased relative power in θ, α, β₁ and β₂ bands in the right centrotemporal areas over the spike zone and in the right temporo-parieto-occipital junction. Furthermore, the relative power in all bands significantly decreased in the bilateral frontal and parieto-occipital areas of patients regardless of the presence or absence of spikes in EEG segments. However, the spectral differences between patients and controls were more pronounced in the presence of spikes. This observation emphasized the impact of benign epilepsy on cortical source power, especially in the right centrotemporal regions. Spectral changes in bilateral frontal and parieto-occipital areas may also suggest alterations in the default mode network in BECTS patients.

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BECTS patients exhibited enhanced θ activity over all cortical regions.

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BECTS patients displayed reduced α activity at the occipital regions.

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Patients showed increased power in θ, α, β in right temporo-parieto-occipital pole.

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EEG spectral changes in BECTS patients indicate dysfunction at the epileptic zone.

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EEG spectral changes in BECTS patients may show alteration in default mode network.

[Formula: see text]Differences in memory functioning between children with attention-deficit/hyperactivity disorder and/or focal epilepsy

Prior research has shown that attention-deficit/hyperactivity disorder (ADHD) and epilepsy are frequently comorbid and that both disorders are associated with various attention and memory problems. Nonetheless, limited research has been conducted comparing the two disorders in one sample to determine unique versus shared deficits. Hence, we investigated differences in working memory (WM) and short-term and delayed recall between children with ADHD, focal epilepsy of mixed foci, comorbid ADHD/epilepsy and controls. Participants were compared on the Core subtests and the Picture Locations subtest of the Children's Memory Scale (CMS). Results indicated that children with ADHD displayed intact verbal WM and long-term memory (LTM), as well as intact performance on most aspects of short-term memory (STM). They performed worse than controls on Numbers Forward and Picture Locations, suggesting problems with focused attention and simple span for visual-spatial material. Conversely, children with epilepsy displayed poor focused attention and STM regardless of the modality assessed, which affected encoding into LTM. The only loss over time was found for passages (Stories). WM was intact. Children with comorbid ADHD/epilepsy displayed focused attention and STM/LTM problems consistent with both disorders, having the lowest scores across the four groups. Hence, focused attention and visual-spatial span appear to be affected in both disorders, whereas additional STM/encoding problems are specific to epilepsy. Children with comorbid ADHD/epilepsy have deficits consistent with both disorders, with slight additive effects. This study suggests that attention and memory testing should be a regular part of the evaluation of children with epilepsy and ADHD.