Functional connectivity of limbic system and prefrontal cortex years after pre-eclampsia: 7-Tesla functional magnetic resonance imaging study

OBJECTIVE

Pre-eclampsia is a vascular complication of pregnancy, associated with a long-term risk of cerebrovascular and mental disorders. We explored whether formerly pre-eclamptic women exhibit differences in functional brain organization, especially in regions that may explain the commonly reported emotional symptoms and cognitive complaints even years after the pregnancy.

METHODS

Formerly pre-eclamptic women and control women with a history of normotensive pregnancy underwent structural and functional 7-Tesla magnetic resonance imaging scans. Using graph theoretical analysis, the efficiency and clustering coefficient of the functional brain network were investigated. The study included local analysis focusing on particular brain structures, such as the limbic system and the prefrontal cortex, and global analysis of the whole cerebrum. Univariable and multivariable linear regression was used to investigate the relationship between brain network-related graph measures and the group (formerly pre-eclamptic or control).

RESULTS

A total of 17 control parous women and 55 women with a history of pre-eclampsia were recruited. The time intervals between the index pregnancy and recruitment were 8.0 and 5.6 years for the two groups, respectively. Compared with control women, formerly pre-eclamptic women had higher local efficiency in the prefrontal cortex (P = 0.048) and anterior cingulate cortex (P = 0.03) but lower local efficiency and local clustering coefficient in the amygdala (P = 0.004 and P = 0.02, respectively) and parahippocampal cortex (P = 0.007 and P = 0.008, respectively). No differences were found in the global functional brain organization.

CONCLUSIONS

Compared to controls with a history of normotensive pregnancy, formerly pre-eclamptic women displayed a different local functional brain organization. These differences in functional connectivity, especially in the limbic regions and the prefrontal cortex, are in line with the psychological and cognitive complaints reported commonly by women with a history of pre-eclampsia. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Blood-brain barrier leakage years after pre-eclampsia: dynamic contrast-enhanced 7-Tesla MRI study

OBJECTIVE

Pre-eclampsia is a hypertensive complication of pregnancy that is associated with an increased risk of long-term cardiovascular and cerebrovascular disorders. Although the underlying mechanism of persistent susceptibility to cerebral complications after pre-eclampsia remains largely unclear, impaired blood-brain barrier (BBB) integrity has been suggested to precede several cerebrovascular diseases. In this study, we aimed to investigate the integrity of the BBB years after pre-eclampsia.

METHODS

This was an observational study of premenopausal formerly pre-eclamptic women and controls with a history of normotensive pregnancy who underwent cerebral magnetic resonance imaging (MRI) at ultra-high field (7 Tesla) to assess the integrity of the BBB. Permeability of the BBB was determined by assessing leakage rate and fractional leakage volume of the contrast agent gadobutrol using dynamic contrast-enhanced MRI. BBB leakage measures were determined for the whole brain and lobar white and gray matter. Multivariable analyses were performed, and odds ratios were calculated to compare women with and those without a history of pre-eclampsia, adjusting for potential confounding effects of age, hypertension status at MRI and Fazekas score.

RESULTS

Twenty-two formerly pre-eclamptic women (mean age, 37.8 ± 5.4 years) and 13 control women with a history of normotensive pregnancy (mean age, 40.8 ± 5.5 years) were included in the study. The time since the index pregnancy was 6.6 ± 3.2 years in the pre-eclamptic group and 9.0 ± 3.7 years in controls. The leakage rate and fractional leakage volume were significantly higher in formerly pre-eclamptic women than in controls in the global white (P = 0.001) and gray (P = 0.02) matter. Regionally, the frontal (P = 0.04) and parietal (P = 0.009) cortical gray matter, and the frontal (P = 0.001), temporal (P < 0.05) and occipital (P = 0.007) white matter showed higher leakage rates in formerly pre-eclamptic women. The odds of a high leakage rate after pre-eclampsia were generally higher in white-matter regions than in gray-matter regions.

CONCLUSION

This observational study demonstrates global impairment of the BBB years after a pre-eclamptic pregnancy, which could be an early marker of long-term cerebrovascular disorders. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Accelerated Cognitive Ageing in epilepsy: exploring the effective connectivity between resting-state networks and its relation to cognitive decline

Objective

This study aims at understanding the dynamic functional brain organization in Accelerated Cognitive Ageing (ACA) in epilepsy. We also assess to which extend the (abnormal) effective connectivity between brain networks correlates with the (estimated) decline in IQ scores observed in the ACA patients.

Material and methods

Two multi-echo resting-state fMRI scans of 10 ACA patients and 14 age- and education-matched healthy controls were acquired. A task-based fMRI was acquired in-between those two scans, for possible cognitive fatigue effects on reserve capacity. Granger causality (GC), a measure of effective connectivity between brain regions, was applied on 7 major cognitive networks, and group-wise compared, using permutation testing statistics. This was performed on each of the resting-state sessions independently. We assessed the correlation between the cognitive deterioration scores (representing cognitive decline), and the paired-networks granger causality values.

Results

The cingulate cortex appeared to be more engaged in ACA patients. Its dynamics towards the right fronto-parietal cortex, salience network, and the dorsal attention networks (DAN) was stronger than in controls, only in the first resting-state scan session. The Granger causality from the DAN to the default mode network (DMN) and from the ventral attention network (VAN) to the left fronto-parietal network (FPL) was also stronger in ACA patients and again only in the first scans. In the second resting-state scans, only the DMN was more strongly connected with the cingulate cortex in ACA patients. A weaker GC from DMN to FPL, and stronger GC from the salience network to cingulate cortex were associated with more decline in the Full-scale IQ and more GC from DMN to VAN would lead to more decline in the Perceptual Reasoning Index in ACA.

Conclusion

The results are in line with the hypothesis of over-recruitment at low cognitive load, and exhaustion at higher cognitive load, as shown by the compensation-related utilization of neural circuits hypothesis (CRUNCH) model for ageing. Moreover, the DMN to VAN directed connectivity strongly correlates with the (estimated) decline in the Perceptual Reasoning Index, which is also in line with a recent study on ageing with mild cognitive impairment in elderly, and the posterior-anterior shift in aging (PASA) model. This study therefore supports the idea that the cognitive decline in our patients resembles the decline observed in healthy ageing, but in an accelerated mode. This study also sheds light on the directions of the impaired connectivity between the main networks involved in the deterioration process, which can be helpful for future development of treatment solutions.

Cognition and quality of life in patients with poststroke epilepsy: A case-control study

INTRODUCTION

Though seizures are a common complication after stroke, only little scientific evidence is available about the impact of epilepsy on cognitive functioning and quality of life in patients who have had a stroke. Therefore, we assessed these items in a case-control study.

METHODS

We studied 36 patients with poststroke epilepsy (PSE) and 36 matched patients who have had a stroke without epilepsy using parts of the FePsy (the computerized visual searching task (CVST) for central information processing speed and a reaction time test), the mini-mental-state examination (MMSE), the EuroQol, the stroke-adapted Sickness Impact Profile questionnaire (SA-SIP-30), the Barthel index, the modified Rankin scale, and the National Institutes of Health stroke scale (NIHSS).

RESULTS

Patients with PSE had significantly lower scores on the CVST and MMSE. Generic quality of life was the same in patients with poststroke epilepsy and patients with stroke only, however, the SA-SIP-30 showed a lower disease-specific quality of life in patients with poststroke epilepsy. The Barthel index showed no difference between both groups, but both the modified Rankin scale and the NIHSS were significantly higher in patients with poststroke epilepsy, indicating more disability and neurological impairment in patients with PSE.

CONCLUSIONS

We found that PSE relates to impaired cognitive functioning, a lower disease-specific quality of life and more disability and neurological impairment. This underlines the importance of further clinical research in this field. This article is part of the Special Issue "Seizures & Stroke".

Classification of intellectual disability according to domains of adaptive functioning and between-domains discrepancy in adults with epilepsy

BACKGROUND

In the Diagnostic and Statistical Manual of Mental Disorders-Fifth edition (DSM-5), the diagnostic criteria of intellectual disability (ID) include three domains of adaptive deficits: the conceptual, social and practical. Substantial intra-individual differences between domains can be considered an ID domain discrepancy.

METHOD

We explored the associations between ID domains, discrepancies and epilepsy in 189 adults (mean age = 47.9; SD = 15.6). Each DSM-5 ID domain was assessed separately, using subscales of the Vineland II for the social and practical domains, and psychological instruments, including intelligence tests, for the conceptual domain. A set of standardised criteria is proposed to identify an ID domain discrepancy.

RESULTS

An ID domain discrepancy seemed to be present in about one-third of subjects and was particularly present in subjects with moderate ID (53.4%). Impairment in the social domain was most often the reason for the discrepancy. The presence of a discrepancy was significantly related to a focal (localised) epilepsy type (OR = 2.3, P = .028) and a mixed seizure type (OR = 1.4, P = .009). Epilepsy characteristics that are indicative of a more severe and refractory epilepsy, including various seizure types, a high seizure frequency, a combined epilepsy type (both focal and generalised epilepsy) and an early age at onset, were significantly related to more severe impairments in conceptual, social and practical adaptive behaviour (all P values <.01).

CONCLUSIONS

With a substantial proportion of the subjects who had both ID and epilepsy with an ID discrepancy, professionals should be aware of this and take all domains of ID into account when studying or working with this vulnerable population.

Failed transition to independence in young adults with epilepsy: The role of loneliness

PURPOSE

Many young adults with epilepsy are still living with their parents ('failed transition to independence') despite reaching the adult age. This study evaluated patient-related variables and measures of loneliness correlated to 'failed transition to independence' in adults, 25-30 years of age, with (childhood-onset) epilepsy.

METHODS

Patients with (childhood-onset) epilepsy and 25-30 years of age were recruited from Epilepsy Center Kempenhaeghe. Inclusion criteria were: diagnosis of (childhood-onset) epilepsy, and an (estimated) IQ > 70. Patients were sent one questionnaire and informed consent was obtained from all participants. Questions included the patient's level of functioning and satisfaction on three transitional domains (medical status, educational/vocational status, independence/separation from their parents), satisfaction with their friendships, and the validated De Jong-Gierveld Loneliness Scale. 'Transition to independence' was defined and categorized in a continuum with scores ranging from 0 ('Failed transition') to 4 for all patients. A Bivariate Correlation analysis was used to compute correlations between patient characteristics and failed transition to independence.

RESULTS

59 patients were included in the analysis, of which 19 (32.2%) had a failed transition to independence. A statistically significant correlation was found between transition to independence and the social loneliness scale (p =  0.047) and the total loneliness scale (p =  0.04), and for the patients self-reported satisfaction with their independence/separation from parents (p =  0.01) and friendships (p =  0.04).

CONCLUSIONS

Adults with epilepsy with a failed transition to independence experience loneliness and are not satisfied with their current developmental and social situation.

The occurrence of seizures after ischemic stroke does not influence long-term mortality; a 26-year follow-up study

Objective

Epileptic seizures are a common complication after stroke. The relation between occurrence of seizures after stroke and long-term mortality remains elusive. We aimed to assess whether seizures in an early or late phase after ischemic stroke are an independent determinant of long-term mortality.

Methods

We prospectively included and followed 444 ischemic stroke patients with a first-ever supratentorial brain infarct for at least 2 years after their stroke regarding the occurrence of seizures. The final follow-up for mortality is from April 2015 (follow-up duration 24.5–27.8 years, mean 26.0 years, SD 0.9 years). We compared patients with early-onset seizures with all seizure-free patients, whereas the patients with late-onset seizures were compared with the 1-week survivors without any seizures. We used Cox-regression analyses to correct for possible confounding factors.

Results

Kaplan–Meier analysis showed significantly higher mortality for the patients with early-onset seizures (p = 0.002) but after correction for known risk factors for (long term) mortality early-onset seizures had no independent influence on long-term mortality (HR 1.09; 95% CI 0.64–1.85). In patients with late-onset seizures, no significant influence from late-onset seizures on long-term mortality was found (univariate p = 0.717; multivariate HR 0.81; 95% CI 0.54–1.20).

Conclusion

Both early-onset and late-onset seizures do not influence long-term mortality after ischemic stroke.

Cognitive deterioration in adult epilepsy: clinical characteristics of "Accelerated Cognitive Ageing"

OBJECTIVES

"Epileptic dementia" is reported in adults with childhood-onset refractory epilepsy. Cognitive deterioration can also occur in a "second-hit model".

MATERIALS AND METHODS

We studied the clinical and neuropsychological characteristics of patients with cognitive deterioration (≥1 SD discrepancy between current IQ and premorbid IQ). Memory function, reaction time and processing speed were also evaluated. Analyses were performed to investigate which clinical characteristics correlated with cognitive deterioration.

RESULTS

Twenty-seven patients were included with a mean age of 55.7 years old, an average age at epilepsy onset of 33.9 years and a mean duration of 21.8 years. Over 40% had experienced at least one status epilepticus. About 77.8% had at least one comorbid disease (most of (cardio)vascular origin). Cognitive deterioration scores were significant for both Performance IQ and Full Scale IQ, but not for Verbal IQ. Impairments in fluid functions primarily affected the IQ-scores. Memory was not impaired. Epilepsy factors explained 7% of the variance in deterioration, whereas 38% was explained by relatively low premorbid IQ and educational level, high age at seizure onset and older age.

CONCLUSIONS

A subgroup of patients with localization-related epilepsy exhibits cognitive decline characterized by deterioration in PIQ and FSIQ, but with preserved higher order functions (VIQ and memory). Patients typically have epilepsia tarda, comorbid pathology, relatively low educational level and older age. These are factors known to increase the vulnerability of the brain by diminishing cognitive reserve. Cognitive deterioration may develop according to a stepwise "second-hit model", affecting and accelerating the cognitive ageing process.

A randomized controlled trial of the ketogenic diet in refractory childhood epilepsy

OBJECTIVE

To evaluate the efficacy and tolerability of the ketogenic diet (KD) during the first 4 months of a randomized controlled trial (RCT) in refractory epilepsy patients aged 1-18 years.

METHODS

Children and adolescents with refractory epilepsy, not eligible for epilepsy surgery, were included. Following 1 month at baseline, patients were randomized to either the KD or to care as usual (CAU).Primary outcome is the proportion of patients with at least 50% reduction in seizure frequency at 4 months. Secondary outcomes are mean percentage of baseline seizures, seizure severity, and side effects.

RESULTS

Fifty-seven patients were randomized; nine dropped out, leaving 48 for analysis (i.e., 26 KD, 22 CAU). In an intention-to-treat analysis, 13 patients (50%) treated with the KD and four patients (18.2%) of the CAU group were responders.Mean seizure frequency at 4 months compared to baseline, after removal of two outliers in the KD group, was significantly lower (P = 0.024) in the KD group (56%) (95% CI: 36-76) than in the CAU group (99%) (95% CI: 65-133%).Twice as many patients in the KD group had a relevant decrease in seizure severity score (P = 0.070).Patients treated with the KD had a significantly higher score for gastrointestinal symptoms (P = 0.021) without an increase in the total score of side effects.

CONCLUSIONS

This trial provides class I evidence that the KD is an effective therapy in children and adolescents with refractory epilepsy compared with CAU. Most often reported side effects are gastrointestinal symptoms.The study has been registered with the Netherlands Trial Registry (NTR2498).

Mental slowing in relation to epilepsy and antiepileptic medication

OBJECTIVES

Slowing of the central information-processing speed (CIPS) is frequently observed in epilepsy as a consequence of epileptic seizures and/or antiepileptic drugs (AEDs). A variety of neuropsychological tests are used to asses this 'mental slowing,' but it is highly questionable whether the different tasks measure the same cognitive process. Also, it remains unspecified to which degree the various tasks are sensitive to seizure- or treatment-related factors, or both.

METHODS

We used an open clinical non-comparative study design. The sample consisted of adult patients with cryptogenic localization-related epilepsy who performed different cognitive measures of CIPS and psychomotor speed (PmS). Clinical data about their seizures and antiepileptic drug treatment were collected from an electronic patient database.

RESULTS

Eighty patients were included. CIPS tasks mutually correlated significantly, but did not correlate with measures of PmS (finger tapping and reaction time). Also, the CIPS tasks were differently affected by treatment and seizure effects. Processing of complex information is affected by tonic-clonic seizures, while less complex tasks are more sensitive for AED effects.

CONCLUSIONS

CIPS tasks are mainly measuring central processing, and the psychomotor component of these tasks is negligible. We propose a psychometric continuum on which PmS and CIPS tasks are ordered with ascending complexity. The model shows that the tasks are affected differently by seizures, treatment, age, and education level. In neuropsychological practice, this continuum can be helpful in the detection of treatment and seizure effects on the CIPS in epilepsy.

Evaluation of a multidisciplinary epilepsy transition clinic for adolescents

INTRODUCTION

The main goal of the transition clinic is to explore and optimize medical issues during transition from adolescence to adulthood, and to ease the transition into adult care. However, only limited data on the process and outcomes of transitional care in clinical practice are available.

OBJECTIVE

To describe the process and outcomes of an Epilepsy Transition Clinic in a tertiary referral center in The Netherlands.

METHODS

Data were collected from patients with epilepsy (aged 15-25 years), who visited the transition clinic between March 2012 and September 2014.

RESULTS

The Epilepsy Transition Clinic is staffed with a multidisciplinary team including a neurologist/epileptologist, clinical neuropsychologist, a social worker and an educationalist/occupational counselor, all with knowledge of paediatric and adult medical and developmental issues. In total, 117 patients with epilepsy were included in the analysis. After consultation, 89 patients received a diagnostic work-up (76.1%), change in AED prescription (n = 64, 54.7%), or consultation/tailored advice (n = 73, 62.4%). In fourteen patients (12.0%) the epilepsy diagnosis was changed. Nineteen patients (16.2%) had complete epilepsy remission for over one year. Forty-three patients (36.8%) were referred to adult care.

CONCLUSION

This study describes a multidisciplinary epilepsy transition clinic staffed by a neurologist/epileptologist, neuropsychologist, a social worker and an educationalist/occupational counselor. Diagnostic work-up and evaluation of psychosocial and educational/vocational status during adolescence are strongly recommended.

Technical aspects of neurostimulation: Focus on equipment, electric field modeling, and stimulation protocols

Neuromodulation is a field of science, medicine, and bioengineering that encompasses implantable and non-implantable technologies for the purpose of improving quality of life and functioning of humans. Brain neuromodulation involves different neurostimulation techniques: transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), vagus nerve stimulation (VNS), and deep brain stimulation (DBS), which are being used both to study their effects on cognitive brain functions and to treat neuropsychiatric disorders. The mechanisms of action of neurostimulation remain incompletely understood. Insight into the technical basis of neurostimulation might be a first step towards a more profound understanding of these mechanisms, which might lead to improved clinical outcome and therapeutic potential. This review provides an overview of the technical basis of neurostimulation focusing on the equipment, the present understanding of induced electric fields, and the stimulation protocols. The review is written from a technical perspective aimed at supporting the use of neurostimulation in clinical practice.

Diagnostic overshadowing in a population of children with neurological disabilities: A cross sectional descriptive study on acquired ADHD

AIM

Diagnostic overshadowing refers to the underdiagnosis of comorbid conditions in children with known neurological diagnoses. To demonstrate diagnostic overshadowing we determined the prevalence of attention deficit-hyperactivity disorders (ADHD) in a cohort of children with a wide range of neurological disabilities.

METHOD

The study cohort consisted of 685 children (mean age 10.3 years, SD: 3.1; 425 boys and 260 girls) who visited a tertiary outpatient multidisciplinary clinic for neurological learning disabilities. Patients with ADHD were identified by retrospective chart review using DSM-IV criteria.

RESULTS

The prevalence of ADHD in this cohort was 38.8% (266 children); of these children only 28.2% (75 children) were diagnosed with ADHD before referral.

INTERPRETATION

ADHD is a common problem in children with neurological disabilities and may be underdiagnosed due to overshadowing of somatic, physical or syndromal features of the disability. In our heterogeneous population ADHD was overshadowed in 71.8% of the cases. This finding may have important implications for diagnosis and treatment of mental health needs in children with neurological disabilities.

Autism and behavior in adult patients with Dravet syndrome (DS)

INTRODUCTION

Autism and behavioral characteristics in adults with Dravet syndrome (DS) have rarely been systematically studied.

METHOD

Three scales were used to assess the outcomes of DS in adulthood in terms of autism and behavior. All the adult patients with DS, nine male and four female, aged between 18 and 60 years, living at the Epilepsy Center Kempenhaeghe in The Netherlands were included in the study. In addition, the past medical history of each patient was systematically screened for diagnoses like autism, Pervasive Development Disorder-Not Otherwise Specified (PDD-NOS), autism spectrum disorder (ASD), hyperactivity, Attention Deficit Hyperactivity Disorder (ADHD), and self-mutilation. Information concerning past and current use of psychoactive drugs was also evaluated.

RESULTS

Eight patients (61.5%) were classified as having autism spectrum disorder (ASD) according to the AVZ-R or according to the medical record. Self-mutilation was seen in four patients (30.8%), hyperactivity in none. Three patients (23.1%) currently used psychoactive drugs.

CONCLUSION

Autism spectrum disorders persist in adult patients with DS, while certain characteristics associated with behavioral problems, such as hyperactivity or use of psychoactive medication, seem to be less prominent than in childhood.

Cognitive effects of lacosamide as adjunctive therapy in refractory epilepsy

BACKGROUND

Lacosamide (LCM) is a novel antiepileptic drug (AED) with potential benefit as adjunctive treatment in patients with partial-onset seizures. As yet, limited information on cognitive effects of LCM is available, especially in real-life settings.

AIMS

In this open clinical prospective study, the cognitive effects of LCM were evaluated when used as adjunctive antiepileptic therapy in patients with refractory epilepsy.

METHODS

We included 33 patients aged between 16 and 74 years (mean: 37 years). All patients had a localization-related epilepsy. Patients were assessed at baseline before starting LCM treatment and during follow-up when the optimal clinical dose was achieved.

MATERIALS

Subjective complaints were evaluated using the SIDAED; effects on cognition were evaluated using the computerized visual searching task (CVST).

RESULTS

The CVST showed significant faster information processing reaction times at the second evaluation (P = 0.013), which was not correlated with seizure control, type of epilepsy, age, gender, drug load, number of concomitant drugs, dose or duration of LCM treatment. On the SIDAED, patients complained more about their cognitive function at the second evaluation (P = 0.005). For the SIDAED, a positive correlation at follow-up was found between the total severity score and higher age (r = 0.375, P = 0.031), but not with epilepsy factors or treatment characteristics.

DISCUSSION/CONLUSION

Screening of the cognitive effects of LCM showed that LCM does not have negative effects on information processing speed. As this is the most sensitive function for cognitive side effects of AEDs, LCM does not seem to induce the common negative cognitive effects. Remarkably, patients complained more, especially about their cognitive function, which is possible the 'doing better, feeling worse phenomenon'.

Changes in the frequency of benign focal spikes accompany changes in central information processing speed: a prospective 2-year follow-up study

We prospectively examined whether changes in the frequency of benign focal spikes accompany changes in cognition. Twenty-six children with benign focal spikes (19 with Rolandic epilepsy) and learning difficulties were examined with repeated 24-hour EEG recordings, three cognitive tests on central information processing speed (CIPS), and questionnaires on cognition and behavior at baseline, 6months, and 2years. Antiepileptic drug changes were allowed when estimated necessary by the treating physician. At baseline, a lower CIPS was correlated with a higher frequency of diurnal interictal epileptiform discharges (IEDs) and with worse academic achievement. At follow-up, there was a significant correlation between changes in CIPS and EEG changes in wakefulness (in the same direction) when the EEG outcome was dichotomized in IED frequency "increased" or "not increased". Behavioral problems were more often observed in patients with higher frequency of IEDs in sleep at baseline and in those with ongoing IEDs compared with those with EEG remission (without or with sporadic IEDs in the recording) at the end of the study period. No changes were observed in the results of the questionnaires. A lower diurnal IED frequency at baseline, lack of serial IEDs, and occurrence of only unilateral IEDs were correlated with a higher chance of EEG remission at 2-year follow-up. Electroencephalography remission could not be predicted from other epilepsy variables except from seizure freedom in the last six months. Our results confirm the nonbenign character of 'benign' focal spikes. Whether an early and stable EEG remission can be achieved through antiepileptic treatment and whether this is of benefit for cognitive development should be examined in prospective placebo-controlled randomized trials.

Inter- and intraobserver agreement of seizure behavior scoring in the amygdala kindled rat

INTRODUCTION

The Racine scale is a 5-point seizure behavior scoring paradigm used in the amygdala kindled rat. Though this scale has been applied widely in experimental epilepsy research, studies of reproducibility are rare. The aim of the current study was, therefore, to assess its interobserver variability and intraobserver variability.

MATERIAL AND METHODS

A video database set was acquired in the course of amygdala kindling of 67 Wistar rats. Six blinded observers received scoring instructions and then viewed a set of 15 random videos (session #1). Next, each observer scored 379 to 1048 additional videos (session #2) and finally scored the same set of 15 videos again (session #3). Scores included the occurrence of seizures (yes or no), the total seizure time (start of stimulus until the absence of seizure behavior), and the highest Racine stage. Interobserver variability and intraobserver variability were assessed in and between sessions #1 and #3 using a 2-way mixed intraclass correlation or Cohen's kappa depending on the variable.

RESULTS

Interobserver agreement in session #1 was 0.664 for seizure occurrence, 0.861 for total seizure time, and 0.797 for the highest Racine stage. In session #3, interobserver agreement on seizure occurrence declined to 0.492, total seizure time declined to 0.625, and agreement for the highest Racine stage was 0.725. Interobserver agreement was scored insufficiently on focal R2 seizures in both sessions (0.287 and 0.182). Intraobserver agreement reached >0.80 agreement for seizure occurrence, highest seizure score, and total seizure time in 3 out of 4 observers. Racine's scale stage 2 seizure scores were only 0.135 in one observer but 0.650, 0.810, and 0.635 in the other observers.

DISCUSSION AND CONCLUSION

Overall, interobserver agreement and intraobserver agreement in scoring with Racine's scale were adequate. However, because interobserver agreement declined after a period of individually scoring videos, we suggest periodic repetition of the standardized instruction in the course of evaluating videos in order to ensure reproducible results.

Aetiology of cognitive impairment in children with frontal lobe epilepsy

OBJECTIVES

Cognitive impairment is frequent in children with frontal lobe epilepsy (FLE), but its aetiology is unknown. MRI scans often reveal no structural brain abnormalities that could explain the cognitive impairment. This does not exclude more subtle morphological abnormalities that can only be detected by automated morphometric techniques.

AIMS

With these techniques, we investigate the relationship between cortical brain morphology and cognitive functioning in a cohort of children with FLE and healthy controls.

MATERIALS AND METHODS

Thirty-four children aged 8-13 years with FLE of unknown cause and 41 healthy age-matched controls underwent neuropsychological assessment and structural brain MRI. Patients were grouped as cognitively impaired or unimpaired. Intracranial volume, white matter volume, lobular cortical volume, cortical thickness and volumes of cortex structures were compared between patients and controls, and potential correlations with cognitive status were determined.

RESULTS

The group of cognitively impaired children with FLE had significantly smaller left temporal cortex volumes, specifically middle temporal grey matter volume and entorhinal cortex thickness. In addition, cognitively impaired children with FLE had smaller volumes of structures in the left and right frontal cortex, right temporal cortex and the left subcortical area.

CONCLUSION

Cognitively impaired children with FLE have smaller volumes of various cortex structures within the frontal lobes and in extra-frontal regions, most notably temporal cortex volumes. These findings might well explain the broad scale of cognitive domains affected in children with FLE complicated by cognitive impairment and highlight that FLE impacts on areas beyond the frontal lobe.

The effects of vagus nerve stimulation on tryptophan metabolites in children with intractable epilepsy

BACKGROUND

The mechanism of action of vagus nerve stimulation (VNS) in intractable epilepsy is not entirely clarified. It is believed that VNS causes alterations in cytokines, which can lead to rebalancing the release of neurotoxic and neuroprotective tryptophan metabolites. We aimed to evaluate VNS effects on tryptophan metabolites and on epileptic seizures and investigated whether the antiepileptic effectiveness correlated with changes in tryptophan metabolism.

METHODS

Forty-one children with intractable epilepsy were included in a randomized, active-controlled, double-blind study. After a baseline period of 12 weeks, all children underwent implantation of a vagus nerve stimulator and entered a blinded active-controlled phase of 20 weeks. Half of the children received high-output (therapeutic) stimulation (n=21), while the other half received low-output (active control) stimulation (n=20). Subsequently, all children received high-output stimulation for another 19 weeks (add-on phase). Tryptophan metabolites were assessed in plasma and cerebrospinal fluid (CSF) by use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and compared between high- and low-output groups and between the end of both study phases and baseline. Seizure frequency was recorded using seizure diaries. Mood was assessed using Profile of Mood States (POMS) questionnaires.

RESULTS

Regarding tryptophan metabolites, anthranilic acid (AA) levels were significantly higher at the end of the add-on phase compared with baseline (p=0.002) and correlated significantly with improvement of mood (τ=-0.39, p=0.037) and seizure frequency reduction (τ=-0.33, p<0.01). No significant changes were found between high- and low-output groups regarding seizure frequency.

CONCLUSION

Vagus nerve stimulation induces a consistent increase in AA, a neuroprotective and anticonvulsant tryptophan metabolite. Moreover, increased AA levels are associated with improvement in mood and reduction of seizure frequency.

Pediatric frontal lobe epilepsy: white matter abnormalities and cognitive impairment

OBJECTIVES

Cognitive impairment is frequent in children with frontal lobe epilepsy (FLE). Its etiology remains unknown. With diffusion tensor imaging, we have studied cerebral white matter properties and associations with cognitive functioning in children with FLE and healthy controls.

METHODS

Thirty children aged 8-13 years with FLE of unknown cause and 39 healthy age-matched controls underwent neuropsychological assessment, structural and diffusion-weighted brain MRI. Patients were grouped as cognitively impaired or unimpaired, and their white matter diffusion properties were compared with the controls.

RESULTS

Children with FLE had reduced apparent diffusion coefficients in various posteriorly located tract bundles, a reduced fractional anisotropy (FA) of the white matter tract between the right frontal and right occipital lobe, and smaller volumes of several collections of interlobar bundle tracts, compared with controls. The cognitively impaired patient group demonstrated significant increases in FA of the white matter of both occipital lobes, a reduced FA of white matter tract bundles between the right frontal and both left occipital lobe and subcortical white matter area, and smaller volumes of two collections of tract bundles connecting the frontal lobe with the temporal and parietal lobes, compared with controls.

CONCLUSIONS

Children with FLE had white matter abnormalities mainly in posterior brain regions, not confined to the area of the seizure focus. Cognitively impaired children with FLE showed the most pronounced white matter abnormalities. These possibly reflect disturbed maturation and might be part of the etiology of the cognitive impairment.

Disentangling the relationship between epilepsy and its behavioral comorbidities - the need for prospective studies in new-onset epilepsies

It has been long recognized that there is more to epilepsy than seizures. The prevalence of such neurobehavioral abnormalities as cognitive and mood disorders, autism spectrum disorder, and attention deficit and hyperactivity disorder (ADHD) is significantly higher among patients with epilepsy than in the general population. A long-held view that comorbidities of epilepsy represent mere epiphenomena of seizures has undergone substantial transformation during the past decade, as emerging clinical evidence and experimental evidence suggest the involvement of specific neurobiological mechanisms in the evolution of neurobehavioral deficits in patients with epilepsy. Developmental aspects of both epilepsy and its comorbidities, as well as the frequently reported reciprocal connection between these disorders, both add other dimensions to the already complex problem. In light of progress in effective seizure management in many patients with epilepsy, the importance of neurobehavioral comorbidities has become acute, as the latter are frequently more detrimental to patients' quality of life compared with seizures. This calls for a serious increase in efforts to effectively predict, manage, and ideally cure these comorbidities. Coordinated multicenter clinical, translational, and basic research studies focusing on epidemiology, neuropsychology, neurophysiology, imaging, genetics, epigenetics, and pharmacology of neurobehavioral comorbidities of epilepsy are absolutely instrumental for ensuring tangible progress in the field. Clinical research should focus more on new-onset epilepsy and put particular emphasis on longitudinal studies in large cohorts of patients and groups at risk, while translational research should primarily focus on the development of valid preclinical systems which would allow investigating the fundamental mechanism of epilepsy comorbidities. The final goal of the described research efforts would lie in producing an armamentarium of evidence-based diagnostic tools and therapeutic interventions which would at minimum mitigate and at maximum prevent or abolish neurobehavioral comorbidities of epilepsy and, thus, improve the quality of life of those patients with epilepsy who suffer from the said comorbidities.

Neurophysiological correlates of dissociative symptoms

OBJECTIVE

Dissociation is a mental process with psychological and somatoform manifestations, which is closely related to hypnotic suggestibility and essentially shows the ability to obtain distance from reality. An increased tendency to dissociate is a frequently reported characteristic of patients with functional neurological symptoms and syndromes (FNSS), which account for a substantial part of all neurological admissions. This review aims to investigate what heart rate variability (HRV), EEG and neuroimaging data (MRI) reveal about the nature of dissociation and related conditions.

METHODS

Studies reporting HRV, EEG and neuroimaging data related to hypnosis, dissociation and FNSS were identified by searching the electronic databases Pubmed and ScienceDirect.

RESULTS

The majority of the identified studies concerned the physiological characteristics of hypnosis; relatively few investigations on dissociation related FNSS were identified. General findings were increased parasympathetic functioning during hypnosis (as measured by HRV), and lower HRV in patients with FNSS. The large variety of EEG and functional MRI investigations with diverse results challenges definite conclusions, but evidence suggests that subcortical as well as (pre)frontal regions serve emotion regulation in dissociative conditions. Functional connectivity analyses suggest the presence of altered brain networks in patients with FNSS, in which limbic areas have an increased influence on motor preparatory regions.

CONCLUSIONS

HRV, EEG and (functional) MRI are sensitive methods to detect physiological changes related to dissociation and dissociative disorders such as FNSS, and can possibly provide more information about their aetiology. The use of such measures could eventually provide biomarkers for earlier identification of patients at risk and appropriate treatment of dissociative conditions.

Antiepileptic drugs and high prevalence of low bone mineral density in a group of inpatients with chronic epilepsy

PURPOSE

Long-term antiepileptic drug use is associated with low bone mineral density (BMD), fractures and abnormalities in bone metabolism. We aimed at determining the prevalence of bone mineral disorders in patients with refractory epilepsy treated with antiepileptic drugs.

METHODS

A cross-sectional survey was conducted in adult patients (n = 205) from a residential unit of a tertiary epilepsy centre. Screening for bone mineral disorders was performed with dual-energy X-ray absorptiometry (DXA) scan of spine and hip (including bone mineral density and vertebral fracture assessment) and laboratory measurements. Patient information regarding demography, epilepsy characteristics and medication use was recorded. Based on DXA T-scores, prevalence of bone mineral disorders (osteopenia and osteoporosis) was calculated. Correlations between DXA T-scores and epilepsy parameters were explored.

RESULTS

Of the 205 patients, there were 10 dropouts. 80% (n = 156/195) of the patients had low BMD: 48.2% had osteopenia and 31.8% had osteoporosis. Of those having low BMD, 51.9% (n = 81/195) was between 18 and 50 years. The T-score of the femoral neck correlated significantly with total duration of epilepsy, cumulative drug load and history of fractures. Linear regression analysis showed that of the epilepsy-related parameters, only cumulative drug load significantly predicted low femoral neck T-score (P = 0.001).

CONCLUSION

In this high-risk population, we obtained a very high prevalence of 80% of low BMD. Both men and women were affected as well as patients <50 years of age. This study illustrates the magnitude of the problem of bone mineral disorders in chronic epilepsy.

Parenting and restrictions in childhood epilepsy

PURPOSE

From the overprotection literature, the predictive and interactional (moderation) effects of controlling and indulgent parenting on restrictions in children with epilepsy were examined.

METHODS

Parents of 73 children with epilepsy completed questionnaires on parenting, restrictions, and functional status. Predictive and moderation effects were tested using multiple regression analysis. Moderation was tested with interactive computational methods.

RESULTS

Restrictions were significantly (R(2)=.38, FΔ=6.59***, p<.001) predicted from seizure frequency (β=.24*, p<.05), functional status (β=-.42***, p<.001), and interaction between controlling and indulgent parenting (β=.28**, p<.01). Moderation occurred predominantly for high values of control: controlling parents who were not indulgent imposed fewer restrictions. In contrast, controlling parents who were indulgent imposed more restrictions.

CONCLUSION

Parents who were controlling and more indulgent imposed more restrictions. Clinicians should ask parents about parenting and restrictions. Future research should examine whether the current study's findings can be replicated.

Subgroup classification in patients with psychogenic non-epileptic seizures

INTRODUCTION

In this open non-controlled clinical cohort study, the applicability of a theoretical model for the diagnosis of psychogenic non-epileptic seizures (PNES) was studied in order to define a general psychological profile and to specify possible subgroups.

METHODS

Forty PNES patients were assessed with a PNES "test battery" consisting of eleven psychological instruments, e.g., a trauma checklist, the global cognitive level, mental flexibility, speed of information processing, personality factors, dissociation, daily hassles and stress and coping factors.

RESULTS

The total PNES group was characterized by multiple trauma, personality vulnerability (in a lesser extent, neuropsychological vulnerabilities), no increased dissociation, many complaints about daily hassles that may trigger seizures and negative coping strategies that may contribute to prolongation of the seizures. Using factor analysis, specific subgroups were revealed: a 'psychotrauma subgroup', a 'high vulnerability somatizing subgroup' (with high and low cognitive levels) and a 'high vulnerability sensitive personality problem subgroup'.

CONCLUSION

Using a theoretical model in PNES diagnosis, PNES seem to be a symptom of distinct underlying etiological factors with different accents in the model. Hence, describing a general profile seems to conceal specific subgroups with subsequent treatment implications. This study identified three factors, representing two dimensions of the model, that are essential for subgroup classification: psychological etiology (psychotrauma or not), vulnerability, e.g., the somatization tendency, and sensitive personality problems/characteristics ('novelty seeking'). For treatment, this means that interventions could be tailored to the main underlying etiological problem. Also, further research could focus on differentiating subgroups with subsequent treatment indications and possible different prognoses.

Ketogenic diet effects on cognition, mood, and psychosocial adjustment in children

INTRODUCTION

The ketogenic diet (KD) is increasingly used for the treatment of refractory epilepsy. The aim of this study was to evaluate possible adverse effects of the diet on cognition, behavior, psychosocial adjustment, and quality of life in school-aged children and adolescents.

METHOD

Fifteen subjects were assessed before diet initiation. After approximately 6 months, on diet treatment 11 patients (73%) were reassessed. We used a combination of individually administered psychological tests for the children and parent report questionnaires.

RESULTS

Five of 15 patients had a seizure reduction of more than 50%. Cognition showed a small trend toward improvement in most patients. Psychosocial adjustment, on the other hand, showed small trends toward worsening. For mood, two areas showed a larger change, revealing more mood problems although this was not on a statistically significant level.

CONCLUSION

In this small group of children, there is no indication that the KD has a negative impact on cognition or social adaptation at short term. There is a tendency toward an increase in mood problems.

Abnormal modular organization of functional networks in cognitively impaired children with frontal lobe epilepsy

Many children with frontal lobe epilepsy (FLE) have significant cognitive comorbidity, for which the underlying mechanism has not yet been unraveled, but is likely related to disturbed cerebral network integrity. Using resting-state fMRI, we investigated whether cerebral network characteristics are associated with epilepsy and cognitive comorbidity. We included 37 children with FLE and 41 healthy age-matched controls. Cognitive performance was determined by means of a computerized visual searching task. A connectivity matrix for 82 cortical and subcortical brain regions was generated for each subject by calculating the inter-regional correlation of the fMRI time signals. From the connectivity matrix, graph metrics were calculated and the anatomical configuration of aberrant connections and modular organization was investigated. Both patients and controls displayed efficiently organized networks. However, FLE patients displayed a higher modularity, implying that subnetworks are less interconnected. Impaired cognition was associated with higher modularity scores and abnormal modular organization of the brain, which was mainly expressed as a decrease in long-range and an increase in interhemispheric connectivity in patients. We showed that network modularity analysis provides a sensitive marker for cognitive impairment in FLE and suggest that abnormally interconnected functional subnetworks of the brain might underlie the cognitive problems in children with FLE.

Epilepsy: fractures and the role of cumulative antiepileptic drug load

BACKGROUND

An association between antiepileptic drugs (AEDs), low bone mineral density (BMD), fractures, and abnormalities in bone metabolism has been suggested for a longer period, although conclusive evidence has not been reported. We aimed at studying patient characteristics in a high-risk population.

METHODS

All adult patients from a residential unit of a tertiary epilepsy center who were diagnosed with osteoporosis and consequently treated with a bisphosphonate at that moment were included. Correlations between reported fractures and patient characteristics were explored.

RESULTS

Of the total population of 261 adult patients, 54 patients were included resulting in a high prevalence rate of 21% osteoporosis in this population. The number of fractures correlated significantly with ambulatory status (r = -0.269, P = 0.05), drug load (r = 0.286, P = 0.04), and current number of AEDs (r = 0.283, P = 0.04). Correlations could not be provided for individual drugs in our population as only a minority was on monotherapy and even less patients had always been on monotherapy of the same antiepileptic drug. Linear regression analysis showed that cumulative drug load (defined by a surrogate parameter: the total duration of epilepsy multiplied by the number of AEDs) was the dominant factor explaining the occurrence of fractures.

CONCLUSION

In this high-risk population, we obtained a positive and strong correlation between the occurrence of fractures in a diagnosed population with osteoporosis and the cumulative drug load of AEDs. This effect seems general, independent of the type of AEDs that were used.

Reading performance in children with rolandic epilepsy correlates with nocturnal epileptiform activity, but not with epileptiform activity while awake

OBJECTIVE

An association between language impairment and rolandic epilepsy is frequently reported. This impairment could be correlated with the amount of nocturnal epileptiform activity.

METHODS

We retrospectively analyzed 26 children with rolandic epilepsy and/or rolandic spikes. All had undergone a 24-hour EEG and neuropsychological assessment within 2 weeks. Reading performance (reading words and sentences) and intelligence were measured.

RESULTS

There was a significant negative correlation between amount of nocturnal epileptiform activity and reading sentences R=-0.525 (P=0.008). There was a trend in this correlation for reading words R=-0.398 (P=0.054). We found a negative correlation between amount of nocturnal epileptiform activity and Verbal IQ (R=-0.51 P=0.08). No correlation was found between reading performance or Verbal IQ and amount of diurnal epileptiform activity.

CONCLUSIONS

Reading performance is impaired in children with rolandic epilepsy and is correlated with the amount of nocturnal epileptiform activity.

Antiepileptic drugs with mood stabilizing properties and their relation with psychotropic drug use in institutionalized epilepsy patients with intellectual disability

A large number of patients with epilepsy and intellectual disability take medication, amongst which antiepileptic and psychotropic drugs, often simultaneously. Certain antiepileptic drugs have mood-stabilizing properties, e.g. carbamazepine, valproic acid and lamotrigine. The aim of this study was to investigate whether the use of these mood-stabilizers is associated with a different use of psychotropic drugs in a population of institutionalized epilepsy patients with intellectual disability. We performed a retrospective, cohort study of adults with intellectual disability and epilepsy at the long-stay department of an epilepsy centre in The Netherlands. 246 residents were included. In patients using lamotrigine we found a statistically significant lower use of antidepressants. We also found significant less prescriptions of anxiolytics in patients using AEDs with mood-stabilizing properties (carbamazepine, valproic acid and lamotrigine). When considering the effect of gender, we found that male patients took significantly more antipsychotics. Most important, we found an inverse relation between the drug load of carbamazepine and/or valproic acid and/or lamotrigine and the use of psychotropic drugs. In a population of institutionalized epilepsy patients with intellectual disability, higher drug loads of mood-stabilizing antiepileptic drugs correspond with less use of psychotropic drugs.

Loss of network efficiency associated with cognitive decline in chronic epilepsy

OBJECTIVE

To study the relation between possibly altered whole brain topology and intellectual decline in chronic epilepsy, a combined study of neurocognitive assessment and graph theoretical network analysis of fMRI was performed.

METHODS

Forty-one adult patients with cryptogenic localization-related epilepsy and 23 healthy controls underwent an intelligence test and fMRI with a silent-word generation paradigm. A set of undirected graphs was constructed by cross-correlating the signal time series of 893 cortical and subcortical regions. Possible changes in cerebral network efficiency were assessed by performing graph theoretical network analysis.

RESULTS

Healthy subjects displayed efficient small world properties, characterized by high clustering and short path lengths. On the contrary, in patients with epilepsy a disruption of both local segregation and global integration was found. An association of more pronounced intellectual decline with more disturbed local segregation was observed in the patient group. The effect of antiepileptic drug use on cognitive decline was mediated by decreased clustering.

CONCLUSIONS

These findings support the hypothesis that chronic localization-related epilepsy causes cognitive deficits by inducing global cerebral network changes instead of a localized disruption only. Whether this is the result of epilepsy per se or the use of antiepileptic drugs remains to be elucidated. For application in clinical practice, future studies should address the relevance of altered cerebral network topology in prediction of cognitive deficits and monitoring of therapeutic interventions.

Psychophysiological biomarkers of dissociation in psychogenic non-epileptic seizures

Misdiagnosis of patients with psychogenic non-epileptic seizures (PNES) as having epilepsy is a clinical relevant problem. Considerable problems for the patients, such as unnecessary anticonvulsant medication use and delay of suitable therapy, as well as a considerable economic burden are involved. Furthermore, after the diagnosis of PNES is confirmed, there is a lack of scientific evidence about the most efficient treatment for PNES. Evaluation of contributing factors is necessary. These factors should be implemented in explanatory models for the occurrence of PNES, which should be employed in diagnosis and treatment. Recent evidence suggests a role of deficiencies in neuronal information processing in multiple mental conditions. Although the focus in PNES research over the last two decades primarily has been on differential diagnosis and psychological and environmental factors, abnormalities in psychophysiological characteristics might also be involved in PNES. This review focuses on neurobiological substrates of PNES and dissociation, a trait which is often associated with PNES, to explore whether deviant information processing is involved in the aetiology of PNES. All studies examining the relationship between psychophysiological parameters and PNES have an exploratory character. However, the results suggest that neurophysiological characteristics, such as brain activity as visualized by functional MRI, cardiovascular measurements and neuroendocrine functioning, may be abnormal in patients with PNES. Future investigations should therefore elucidate the exact role of neurophysiological abnormalities in the aetiology of PNES.

Nocturnal epileptiform EEG discharges, nocturnal epileptic seizures, and language impairments in children: review of the literature

This review addresses the effect on language function of nocturnal epileptiform EEG discharges and nocturnal epileptic seizures in children. In clinical practice, language impairment is frequently reported in association with nocturnal epileptiform activity. Vice versa, nocturnal epileptiform EEG abnormalities are a common finding in children with specific language impairment. We suggest a spectrum that is characterized by nocturnal epileptiform activity and language impairment ranging from specific language impairment to rolandic epilepsy, nocturnal frontal lobe epilepsy, electrical status epilepticus of sleep, and Landau-Kleffner syndrome. In this spectrum, children with specific language impairment have the best outcome, and children with electrical status epilepticus of sleep or Landau-Kleffner syndrome, the worst. The exact nature of this relationship and the factors causing this spectrum are unknown. We suggest that nocturnal epileptiform EEG discharges and nocturnal epileptic seizures during development will cause or contribute to diseased neuronal networks involving language. The diseased neuronal networks are less efficient compared with normal neuronal networks. This disorganization may cause language impairments.

Functional connectivity and language impairment in cryptogenic localization-related epilepsy

BACKGROUND

An often underestimated cognitive morbidity in patients with epilepsy is language dysfunction. To investigate the neuronal mechanisms underlying neuropsychological language impairment, activation maps and functional connectivity networks were studied by fMRI of language.

METHOD

Fifty-two patients with cryptogenic localization-related epilepsy and 27 healthy controls underwent neuropsychological assessment of IQ, word fluency, and text reading. fMRI was performed with a standard covert word-generation and text-reading paradigm. Functional connectivity analysis comprised cross-correlation of signal time series of the characteristic and most strongly activated regions involved in the language tasks.

RESULTS

After careful selection, 34 patients and 20 healthy controls were found eligible for analysis. Patients displayed lower IQ, lower fluency word count, and lower number of words correctly read compared to controls. fMRI activation maps did not differ significantly between patients and controls. For the word-generation paradigm, patients with epilepsy had significantly lower functional connectivity than controls in the prefrontal network. Patients performing worse on the word-fluency test demonstrated a significantly lower mean functional connectivity than controls. Text reading demonstrated lower functional connectivity in patients with epilepsy in the frontotemporal network. Similarly, lower mean functional connectivity was observed in patients with lowest reading performance compared to controls. A relation between reduced functional connectivity and performance on word-fluency and text-reading tests was demonstrated in epilepsy patients.

CONCLUSION

Impaired performance on language assessment in epilepsy patients is associated with loss of functional connectivity in the cognitive language networks.

The Cognitive Impact of Epileptiform EEG-Discharges; Relationship With Type of Cognitive Task

In this study we analyzed the effect of differing task dimensions (high vs. low information demand; short vs. long testing duration) on the occurrence of epileptiform EEG-discharges and the cognitive impact of such discharges. We performed this study only in patients with focal discharges as this appears to be the most complicated group to assess any relationship between epileptiform EEG-discharges and cognitive impairment. Seventeen patients with focal discharges in the EEG and an established diagnosis of localization-related (partial) epilepsy were included. The following tasks were used: Low information demand: auditory and visual RT; high information demand: BCRT and CVST. Short testing duration: Arithmetic and Reading; long testing duration: Vocabulary and Block Design. The percentage of patients with epileptiform EEG-discharge and EEG-related cognitive impact were compared using Chi-square testing. The occurrence of epileptiform EEG-discharges was not associated with one of the experimental conditions introduced in our study, that is, high/low information demand or short/long testing period. Also the difference between computerized reaction-time measurement and more traditional 'paper and pencil tasks' such as reading was not statistically significant. The only statistical significant difference was the more frequent occurrence of epileptiform EEG-discharges during tasks that used the visual input mode. In addition, we could identify one test that appeared to be particularly sensitive to direct cognitive effects of epileptiform EEG-discharges. Only for the CVST, the computerized visual searching task, the relationship with epilepsy-related cognitive impact is statistically significant. This test is the most mentally demanding test of the tests presented in our study and measures speed of visual information processing, using complex stimulus patterns and has a long testing duration. Our results do not confirm that any of the investigated task dimensions (high vs. low information demand; short vs. long testing duration) have a dominant effect on the occurrence of epileptiform EEG-discharges and the cognitive impact of such discharges. The effect found for the CVST suggest that three factors combined are necessary to assess the impact of epileptiform EEG-discharges on cognition: visual input mode, longer testing duration and high information processing demand.

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

OBJECTIVE

We 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.

METHODS

One 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.

RESULTS

No 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.

CONCLUSION

Our 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.

Psychogenic non-epileptic seizures--definition, etiology, treatment and prognostic issues: a critical review

In this review we systematically assess our currently available knowledge about psychogenic non-epileptic seizures (PNES) with an emphasis on the psychological mechanisms that underlie PNES, possibilities for psychological treatment as well as prognosis. Relevant studies were identified by searching the electronic databases. Case reports were not considered. 93 papers were identified; 65 of which were studies. An open non-randomized design, comparing patients with PNES to patients with epilepsy is the dominant design. A working definition for PNES is proposed. With respect to psychological etiology, a heterogeneous set of factors have been identified. Not all factors have a similar impact, though. On the basis of this review we propose a model with several factors that may interact in both the development and prolongation of PNES. These factors involve psychological etiology, vulnerability, shaping, as well as triggering and prolongation factors. A necessary first step of intervention in patients with PNES seems to be explaining the diagnosis with care. Although the evidence for the efficacy of additional treatment strategies is limited, variants of cognitive (behavioural) therapy showed to be the preferred type of treatment for most patients. The exact choice of treatment should be based on individual differences in the underlying factors. Outcome can be measured in terms of seizure occurrence (frequency, severity), but other measures might be of greater importance for the patient. Prognosis is unclear but studies consistently report that 1/3rd to 1/4th of the patients become chronic.

Cognitive fMRI and soluble telencephalin assessment in patients with localization-related epilepsy

Objectives - The use of telencephalin as a possible marker for altered cortical function as demonstrated by functional MRI was investigated in a pilot study with 16 patients with localization-related epilepsy and secondarily generalized seizures. Materials and methods - Functional MRI of verbal working memory performance (Sternberg paradigm) and self-regulatory control processes (Stroop paradigm) was used to examine cortical activation in 16 patients with localization-related epilepsy and secondarily generalized seizures. Additionally, blood serum concentrations of soluble telencephalin (marker for neuronal damage) were determined. Results - In three patients (one temporal and two frontal focus), telencephalin was detected. All three patients had lower functional MRI activation in the frontotemporal region (P = 0.04), but not in other regions (P > 0.35) compared with patients without detectable telencephalin. Additionally, an association of levetiracetam and frontotemporal activation was observed. Conclusions - These preliminary data in a heterogeneous group suggest an association between decreased frontotemporal activation on fMRI and both detectable telencephalin serum levels and levetiracetam use. Future longitudinal studies with larger patient groups are required to confirm these observations. It is hypothesized that altered local function of the frontotemporal cortex in localization-related epilepsy might be better predicted by the biochemical marker telencephalin than epilepsy characteristics such as seizure focus.