Adverse cognitive effects of antiepileptic pharmacotherapy: Each additional drug matters

Cognitive profile in BECTS treated with levetiracetam: A 2-year follow-up

INTRODUCTION

Benign epilepsy with centrotemporal spikes (BECTS) is a common epileptic syndrome in childhood, characterized by brief and infrequent partial motor seizures, with or without generalization and mostly recurring during sleep. Because of its favorable efficacy, tolerability, and safety profile, levetiracetam (LEV) monotherapy is often administered in these patients. Long-term effects of LEV therapy and its influence on cognitive functions remain controversial.

PURPOSE

This evaluated the changes in the cognitive profile of children with BECTS treated with LEV monotherapy for 2 years, compared with a control group of children with specific learning disabilities.

METHOD

Our patient cohort included 20 children aged 8-14 years diagnosed as having BECTS and administered LEV monotherapy and 10 age/sex-matched controls with specific learning disabilities. All participants underwent a standardized test for assessing cognitive profile (Wechsler Intelligence Scale for Children - Fourth Edition [WISC-IV]) before drug therapy and after 2 years of treatment. Average LEV blood level and electroencephalographic (EEG) recordings were periodically monitored. Several factors such as age, sex, response to therapy, and EEG pattern changes were considered. Statistical analysis was performed using Student's t-test for paired and independent samples. p < 0.05 was considered statistically significant.

RESULTS

Children administered LEV for 24 months showed a mild but statistically significant improvement in overall cognitive abilities. Verbal skills, visual-perceptual reasoning, working memory, and processing speed showed slight but significant improvement. In the control group, cognitive profile remained substantially unchanged at 2-year follow-up.

CONCLUSIONS

Not only do our data suggest a nonworsening of the cognitive profile in BECTS with LEV but, on the contrary, cognitive scores also improved over time, unlike the control group.

Evaluating the mediating role of executive functions for antiepileptic drugs' effects on IQ in children and adolescents with epilepsy

Several studies suggest that antiepileptic drug (AED) treatment may permanently or reversibly affect intelligence (intelligence quotient [IQ]) in children and adolescents with epilepsy. Since AED treatment preferentially affects attention and executive functions, we evaluated the potentially mediating effect of executive functions in regard to the adverse effects of drug treatment on intelligence. In a retrospective observational study, 178 children and adolescents with refractory and mostly localization-related epilepsies were evaluated in regard to the interrelation of IQ (Wechsler Intelligence Scale for Children [WISC III] short-form), executive functions (EpiTrack-Junior®, a cognitive AED screening test), and drug treatment (drug load). The results indicate that a low IQ was evident in 23%, impaired executive functions in 59% of the patients. Executive functions correlated to IQ (r = 0.60) and the symbol digits and picture arrangement subtests (R² = 0.46) in particular. Odds ratios for impaired executive functions compared to being off drug (33% impaired) increased from 2.0 with one drug (53% impaired) to 9.5 (83% impaired) with at least three drugs. A mediation analysis revealed that drug dependent differences in executive functions mediate the negative effect of the AED load on intelligence. Hence, executive functions appear to link adverse cognitive side effects of AED treatment to intelligence. Considering Catell's two factor model of intelligence, AEDs preferentially affect the aspects of fluid intelligence. The overall impact of AED on intelligence appears mild. It may become relevant, however, when drug-induced impairments persist over longer time intervals during sensitive developmental phases. This issue needs to be addressed in future longitudinal studies.

Impaired processing of response conflicts in mesial temporal lobe epilepsy

Increasing evidence from neuroimaging studies points towards a hippocampal role in resolving approach-avoidance goal conflicts. Furthermore, previous neuroimaging findings suggest that the hippocampus (HC) contributes to successful conflict resolution as it is measured, for example, in a Stroop paradigm. However, it is still an open question whether the hippocampus is indeed causally relevant for resolving cognitive conflicts. Here, we investigated whether conflict resolution performance is affected by hippocampal pathology. N = 30 patients with mesial temporal lobe epilepsy (MTLE), almost exclusively showing MRI signs of hippocampal sclerosis, and an equal number of age-matched healthy controls performed an auditory Stroop paradigm. Participants listened to the words 'high' and 'low', spoken in either a high or a low pitch. Subjects' response time and accuracy to the phonetic information in the presence of incongruent (conflict trials) or congruent (non-conflict trials) semantic information were assessed. In addition, patients' regional grey matter (GM) brain volumes were analysed. We observed an increased effect of conflict on accuracy in patients with MTLE compared to healthy controls. This effect was negatively correlated with right HC volume. The results suggest that the impairment in the resolution of a response conflict is related to hippocampal structural integrity and thus add further support to the notion that the HC is not only involved but even causally relevant for successful cognitive conflict processing.

Executive functioning in children with epilepsy: Genes matter

Pediatric epilepsy has emerged as a chronic medical disease with a characteristic behavioral and cognitive phenotype, which includes compromised executive functioning (EF) and attention-related deficits. However, considerable interindividual variability exists; children often display very different or even opposite outcomes, and some children are more likely than others to develop neurocognitive problems in the face of similar individual and disease-related problems. The factors responsible for this interindividual variability are still largely unknown, but we do know that some genetic factors render the developing brain more susceptible to damage or traumatic experiences than others. Dopamine availability has a neuromodulatory function in the prefrontal cortex (PFC) and especially affects EF. Dopamine availability relates to polymorphisms in the gene encoding catechol-O-methyltransferase (COMT Val158Met), which in turn is affected by the methylation state of its promoter. Allelic variation of the methylenetetrahydrofolate reductase (MTHFR C677T) gene, alters methylation and may influence the methylation state of the COMT promoter. Given this, we tested the hypothesis that these polymorphisms interact in children with epilepsy, and that variability in allelic expression is associated with variability in cognitive phenotype. Executive function was tested directly and indirectly (parent-rated) in 42 children between 5 and 12 years of age. The MTHFR T allele carriers performed worse than MTHFR homozygous CC carriers on indirect EF, and a significant decline was observed when T allele carriers had at least one met allele of the COMT gene, especially on Working Memory. Direct EF was significantly compromised in COMT Val/Val carriers where reduced dopamine availability seems to confer a higher risk in a test that requests a high degree of executive attention and planning. This finding suggests that in children with epilepsy, genes that influence methylation and dopamine availability affect PFC-related EF. Therefore, we should consider genetic vulnerability as a polygenic risk, which might predispose for a particular phenotype and include specific genetic signatures as part of each patient's behavioral and cognitive profile from the moment that we start to take care of the child.

Attention disorders in adults with epilepsy. Determinants and therapeutic strategies

Cognitive consequences in epilepsy are often described in the following domains: verbal memory, language, executive functions, and attention. Attention is involved in all cognitive activities, and attention disorders (AD) are reported in patients with various neurological diseases. This paper proposes to define the concept of AD and its assessment, to consider their determinants in epilepsy and potential therapies (drug or not). ADs are reported in new onset epilepsy, generalized epilepsy of presumed genetic origin, and in focal epilepsy. In focal epilepsy, alertness and divided attention impairment are observed and seem to improve after successful curative surgery. Additional studies are needed to assess the prevalence and nature of AD related to status epilepticus. In the field of therapeutic strategies, anti-epileptic drugs show an impact on AD. Effects of antidepressive drug therapy are not reported, as well as psychotherapy. Cognitive rehabilitation on AD is a promising therapeutic intervention but specific studies are needed to assess its efficacy.

Chronic mild hypoxia promotes hippocampal neurogenesis involving Notch1 signaling in epileptic rats

Cognitive impairment is one of the most common and disabling co-morbidities of epilepsy. It is therefore imperative to find novel treatment approaches to rescue cognitive function among epilepsy patients. Adult neurogenesis is strongly implicated in cognitive function, and mild hypoxia is known to promote the proliferation and differentiation of both embryonic and adult neural stem cells (NSCs). In the present study, we investigated the effect of mild hypoxia on cognitive function and hippocampal neurogenesis of rats with pilocarpine-induced chronic epilepsy. Chronic epilepsy induced marked spatial learning and memory deficits in the Morris water maze that were rescued by consecutively 28 days mild hypoxia exposure (6 h/d at 3000 m altitude equivalent) during the chronic phase. Moreover, mild hypoxia reversed the suppression of hippocampal neurogenesis and the downregulation of NT-3 and BDNF expression in hippocampus and cortex of epileptic rats. Mild hypoxia in vitro also promoted hippocampus-derived NSC proliferation and neuronal differentiation. In addition, mild hypoxia enhanced Notch1 and Hes1 expression, suggesting that Notch1 signaling may be involved in neuroprotection of hypoxia. Our data may help to pave the way for identifying new therapeutic targets for rescuing cognition conflicts in epileptic patients by using hypoxia to promote hippocampus neurogenesis.

Neuropsychological outcome after subtemporal versus transsylvian approach for selective amygdalohippocampectomy in patients with mesial temporal lobe epilepsy: a randomised prospective clinical trial

OBJECTIVE

To compare the effects of different surgical approaches for selective amygdalohippocampectomy in patients with pharmacoresistant mesial temporal lobe epilepsy with regard to the neuropsychological outcome and to replicate an earlier study employing a matched-pair design.

METHOD

47 patients were randomised to subtemporal versus transsylvian approaches. Memory, language, attentional and executive functions were assessed before and 1 year after surgery. Multivariate analyses of variance (MANOVAs) with presurgical and postsurgical assessments as within-subject variables and approach and side of surgery as between-subject factors were calculated. Additionally, the frequencies of individual performance changes based on reliable change indices were analysed.

RESULTS

Seizure freedom International League Against Epilepsy (ILAE) 1a, was achieved in 62% of all patients without group difference. MANOVAs revealed no significant effects of approach on cognition. Tested separately for each parameter, verbal recognition memory declined irrespective of approach. Post hoc tests revealed that on group level, the subtemporal approach was associated with a worse outcome for verbal learning and delayed free recall as well as for semantic fluency. Accordingly, on individual level, more patients in the subtemporal group declined in verbal learning. Left side of surgery was associated with decline in naming regardless of approach.

CONCLUSION

The main analysis did not confirm the effects of approach on memory outcome seen in our previous study. Post hoc testing, however, showed greater memory losses with the subtemporal approach. Previous findings were replicated for semantic fluency. The discrepant results are discussed on the background of the different study designs.

Socio-cognitive functioning in stimulant polysubstance users

BACKGROUND

Using more than one psychotropic substance is accompanied by increased risks for psychiatric and physical disorders. Accordingly, deficits in basal cognitive functions have been consistently associated with polysubstance use (PSU), whereas little is known about potential impairments in more complex socio-cognitive skills, which are relevant for daily-life functioning. Therefore, we investigated the effects of toxicological validated stimulant PSU on social cognition under consideration of potential cumulative effects.

METHODS

We compared socio-cognitive performances of 47 individuals with stimulant PSU with 59 matched stimulant-naïve controls using the Multifaceted Empathy Test (MET) and the Movie for the Assessment of Social Cognition (MASC). Additionally, social network size was assessed by the Social Network Questionnaire (SNQ). Hair and urine testing was employed to categorize three PSU subgroups (3, 4, and ≥5 substances used) and to ensure drug abstinence in controls.

RESULTS

Individuals with stimulant PSU showed lower emotional empathy (MET) and a smaller social network (SNQ) compared to controls (both with linear trends for increasing number of used substances: p < .05). In contrast, cognitive empathy (MET and MASC) was largely unaffected by PSU. Additional linear regression analyses within PSU individuals revealed number of used substances as the best predictor for inferior performance in emotional empathy (p < .01), while severity of the use of single substances or substance-classes did not show a significant impact.

CONCLUSION

These findings demonstrate cumulative adverse effects of stimulant PSU on an important facet of socio-cognitive functioning. Therefore, emotional empathy deficits should be targeted in future interventions and rehabilitations for individuals with PSU.

Affective, neurocognitive and psychosocial disorders associated with traumatic brain injury and post-traumatic epilepsy

Survivors of traumatic brain injury (TBI) often develop chronic neurological, neurocognitive, psychological, and psychosocial deficits that can have a profound impact on an individual's wellbeing and quality of life. TBI is also a common cause of acquired epilepsy, which is itself associated with significant behavioral morbidity. This review considers the clinical and preclinical evidence that post-traumatic epilepsy (PTE) acts as a 'second-hit' insult to worsen chronic behavioral outcomes for brain-injured patients, across the domains of emotional, cognitive, and psychosocial functioning. Surprisingly, few well-designed studies have specifically examined the relationship between seizures and behavioral outcomes after TBI. The complex mechanisms underlying these comorbidities remain incompletely understood, although many of the biological processes that precipitate seizure occurrence and epileptogenesis may also contribute to the development of chronic behavioral deficits. Further, the relationship between PTE and behavioral dysfunction is increasingly recognized to be a bidirectional one, whereby premorbid conditions are a risk factor for PTE. Clinical studies in this arena are often challenged by the confounding effects of anti-seizure medications, while preclinical studies have rarely examined an adequately extended time course to fully capture the time course of epilepsy development after a TBI. To drive the field forward towards improved treatment strategies, it is imperative that both seizures and neurobehavioral outcomes are assessed in parallel after TBI, both in patient populations and preclinical models.

Cognitive and fatigue side effects of anti-epileptic drugs: an analysis of phase III add-on trials

We aimed to investigate the terms used to refer to cognitive and fatigue related side effects and their prevalence in phase III add-on clinical trials of anti-epileptic drugs (AEDs). We extracted data from publicly available FDA documents as well as the published literature. Target drug doses were then calculated as drug loads and divided into three categories (low, average, high). The odds ratio of developing the side effects was calculated for each drug load, and the presence of a dose-response effect was also assessed. We found that the cognitive terms used across trials were very variable, and data on discontinuation rates were limited. Placebo rates for cognitive side effects ranged from 0 to 10.6% while those for fatigue ranged from 2.5 to 37.7%. Keeping in mind the variable placebo rates and terminology, the majority of AEDs exhibited a clear dose response effect and significant odds ratios at high doses except brivaracetam and zonisamide for the cognitive side effects and tiagabine, topiramate, and zonisamide for the fatigue side effects. Due to their clinical relevance and impact on quality of life, new trials should make data related to the prevalence and discontinuation rates of these side effects publicly available. Given the clear dose response effect, physicians should consider aiming for lower drug loads and adjusting doses to improve tolerability.

Effects of carbamazepine and lamotrigine on functional magnetic resonance imaging cognitive networks

OBJECTIVE

To investigate the effects of sodium channel-blocking antiepileptic drugs (AEDs) on functional magnetic resonance imaging (fMRI) language network activations in patients with focal epilepsy.

METHODS

In a retrospective study, we identified patients who were treated at the time of language fMRI scanning with either carbamazepine (CBZ; n = 42) or lamotrigine (LTG; n = 42), but not another sodium channel-blocking AED. We propensity-matched 42 patients taking levetiracetam (LEV) as "patient-controls" and included further 42 age- and gender-matched healthy controls. After controlling for age, age at onset of epilepsy, gender, and antiepileptic comedications, we compared verbal fluency fMRI activations between groups and out-of-scanner psychometric measures of verbal fluency.

RESULTS

Patients on CBZ performed less well on a verbal fluency tests than those taking LTG or LEV. Compared to either LEV-treated patients or controls, patients taking CBZ showed decreased activations in left inferior frontal gyrus and patients on LTG showed abnormal deactivations in frontal and parietal default mode areas. All patient groups showed fewer activations in the putamen bilaterally compared to controls. In a post hoc analysis, out-of-scanner fluency scores correlated positively with left putamen activation.

SIGNIFICANCE

Our study provides evidence of AED effects on the functional neuroanatomy of language, which might explain subtle language deficits in patients taking otherwise well-tolerated sodium channel-blocking agents. Patients on CBZ showed dysfunctional frontal activation and more pronounced impairment of performance than patients taking LTG, which was associated only with failure to deactivate task-negative networks. As previously shown for working memory, LEV treatment did not affect functional language networks.

Affective and behavioral dysfunction under antiepileptic drugs in epilepsy: Development of a new drug-sensitive screening tool

OBJECTIVE

Behavioral problems and psychiatric symptoms are common in patients with epilepsy and have a multifactorial origin, including adverse effects of antiepileptic drugs (AEDs). In order to develop a screening tool for behavioral AED effects, the aim of this study was to identify behavioral problems and symptoms particularly sensitive to AED drug load and the presence/absence of AEDs with known negative psychotropic profiles.

METHODS

Four hundred ninety-four patients with epilepsy were evaluated who had been assessed with three self-report questionnaires on mood, personality, and behavior (Beck Depression Inventory, BDI; Neurological Disorders Depression Inventory for Epilepsy extended, NDDI-E; and Fragebogen zur Persönlichkeit bei zerebralen Erkrankungen, FPZ). Drug-sensitive items were determined via correlation analyses and entered into an exploratory factor analysis for scale construction. The resulting scales were then analyzed as a function of drug treatment.

RESULTS

Analyses revealed 30 items, which could be allocated to six behavioral domains: Emotional Lability, Depression, Aggression/Irritability, Psychosis & Suicidality, Risk- & Sensation-seeking, and Somatization. Subsequent analysis showed significant effects of the number of AEDs on behavior, as in Emotional Lability (F=2.54, p=.029), Aggression/Irritability (F=2.29, p=.046), Psychosis & Suicidality (F=2.98, p=.012), and Somatization (F=2.39, p=.038). Affective and behavioral difficulties were more prominent in those patients taking AEDs with supposedly negative psychotropic profiles. These effects were largely domain-unspecific and primarily manifested in polytherapy.

CONCLUSION

Drug-sensitive behavioral domains and items were identified which qualify for a self-report screening tool. The tool indicates impairments with a higher drug load and when administering AEDs with negative psychotropic profiles. The next steps require normalization in healthy subjects and the clinical validation of the newly developed screening tool PsyTrack along with antiepileptic drug treatment.

Evaluating the longer-term cognitive effects of adjunctive perampanel compared to lacosamide in a naturalistic outpatient setting

PURPOSE

This retrospective longitudinal study aims to compare the longer-term cognitive and behavioral side effects of adjunctive antiepileptic treatment with perampanel (PER) and lacosamide (LCM), two third generation antiepileptic drugs with suggested favorable cognitive profiles. The two drugs were monitored according to a previously established routine diagnostic protocol (Helmstaedter et al. E&B 2013;26:182-7) which facilitates the retrospective comparison of antiepileptic drug tolerability in a naturalistic outpatient setting.

METHODS

Records from 94 patients were evaluated who underwent neuropsychological assessment before and under adjunctive treatment with either PER (n = 57) or LCM (n = 37). Cognition was assessed using the EpiTrack screening for executive functions and a VLMT short form for verbal memory. Subjective assessments included a German QOLIE-10 adaptation (quality of life) and an extended Adverse Events Profile (AEP). The median follow-up interval was 36 weeks.

RESULTS

Multivariate repeated measures statistics revealed a non-significant trend towards an interaction effect "time - treatment arm" on both executive function and memory. When analyzed separately executive functions and memory scores significantly improved under LCM (t = -2.76 p < 0.01 and t = -2.44 p < 0.05 respectively). Subjectively, PER was associated with improvements in 2/18 physiological domains and in the LCM group 1/9 cognitive domains deteriorated. Seizure freedom was achieved for five patients treated with LCM (14%) and 15 treated with PER (26%, χ² = 2.2, n.s.).

CONCLUSION

In a naturalistic outpatient setting, chronic adjunctive treatment with PER and LCM did not negatively affect cognition and LCM may even improve cognition. Neither drug increased self-reported irritability or aggression. This suggests favorable longer-term tolerability.

Lacosamide protects striatal and hippocampal neurons from in vitro ischemia without altering physiological synaptic plasticity

Lacosamide ([(R)-2-acetamido-N-benzyl-3-methoxypropanamide], LCM), is an antiepileptic that exerts anticonvulsant activity by selectively enhancing slow sodium channel inactivation. By inhibiting seizures and neuronal excitability it might therefore be a good candidate to stabilize neurons and protect them from energetic insults. Using electrophysiological analyses, we have investigated in mice the possible neuroprotective effect of LCM against in vitro ischemia obtained by oxygen and glucose deprivation (ODG), in striatal and hippocampal tissues, two brain structures particularly susceptible to ischemic injury and of pivotal importance for different form of learning and memory. We also explored in these regions the influence of LCM on firing discharge and on long-term synaptic plasticity. We found that in both areas LCM reduced the neuronal firing activity in a use-dependent manner without influencing the physiological synaptic transmission, confirming its anticonvulsant effects. Moreover, we found that this AED is able to protect, in a dose dependent manner, striatal and hippocampal neurons from energy metabolism failure produced by OGD. This neuroprotective effect does not imply impairment of long-term potentiation of striatal and hippocampal synapses and suggests that LCM might exert additional beneficial therapeutic effects beyond its use as antiepileptic.

Epilepsy, antiepileptic drugs, and serious transport accidents: A nationwide cohort study

OBJECTIVES

To investigate the association between epilepsy and antiepileptic drugs and serious transport accidents requiring emergency care or resulting in death.

METHODS

We identified 29,220 individuals 18 years or older with epilepsy without cerebral palsy or intellectual disability and 267,637 matched controls using Swedish registers. This nationwide cohort was followed from 2006 to 2013 for serious transport accidents. We used Cox regression to analyze the risk of serious transport accidents between individuals with epilepsy and matched controls, and then stratified Cox regression to compare the risk during periods of medication with the risk during nonmedication period within the same individual with epilepsy. We adjusted for civil status, employment, education, living area, psychiatric disorders prior to the start of follow-up, and psychotropic medication.

RESULTS

Compared to matched controls, individuals with epilepsy were at increased risk of serious transport accidents (hazard ratio [HR] 1.37; 95% confidence interval [CI] 1.29-1.46). There were increased risks of pedestrian accidents (HR 2.24, 95% CI 1.69-2.97), bicycle accidents (HR 1.68, 95% CI 1.49-1.89) and car accidents (HR 1.31, 95% CI 1.19-1.44). However, among patients with a diagnosis of epilepsy, use of antiepileptic drugs did not influence the risk of serious transport accidents in population-level comparisons (HR 0.97; 95% CI 0.85-1.11) or within-individual comparisons (HR 0.99; 95% CI 0.69-1.42).

CONCLUSION

Serious transportation accidents were more common in individuals with epilepsy, but this risk was independent of use of antiepileptic drugs.

Growing older with drug-resistant epilepsy: cognitive and psychosocial outcomes

We aimed to investigate the cognitive and psychosocial outcomes of patients older than 50 with drug-resistant temporal lobe epilepsy as compared to a younger cohort. One hundred and thirty-one patients with temporal lobe epilepsy (47% age ≥ 50) who underwent comprehensive neuropsychological testing were retrospectively identified. A comparison of percentage of Z scores < - 1.5 between the older and younger cohort on Trail Making Tests A and B, Boston Naming Test, Rey Auditory Verbal Learning Test (RAVLT) delayed recall, and Rey-Osterrieth complex figure test delayed recall was performed as well as the presence of disability due to epilepsy and depression scores. Grading of white matter hyperintensities on MRI was also performed. Older patients with epilepsy were more likely to score Z < - 1.5 on the RAVLT (54.1 vs 32.8%) and were more likely to be on disability due to their seizures (23.0 vs 5.7%). A higher grade of white matter hyperintensities correlated with worse performance on Trail Making Test A, while a higher number of anti-epileptic drugs (AEDs) correlated with worse performance on Trail Making Test B regardless of age. The results of this study reveal that older patients with drug-resistant epilepsy are a vulnerable population with an impaired cognitive profile. In addition, limiting the number of AEDs and addressing markers of small vessel disease should also be prioritized by clinicians.

Cognitive and Behavioral Comorbidities: An Unwanted Effect of Antiepileptic Drugs in Children

Epilepsy is one of the most common neurological disorders and, despite optimally chosen and dosed antiepileptic drugs (AEDs), approximately 20%-30% of patients will continue to have seizures. Behavior and cognition are negatively impacted by seizures, but AEDs are also a major contributor to behavioral and cognitive deficits. However, the cognitive and behavioral effect of AEDs in children is insufficiently emphasized in the literature. This review summarizes the cognitive and behavioral effects of AEDs in the pediatric population with the objective of helping pediatricians and pediatric neurologists to select the AEDs with the best profile for their individual patient's needs.

Agmatine for combined treatment of epilepsy, depression and cognitive impairment in chronic epileptic animals

Epilepsy is fourth most common neurological disorders associated with depression and cognitive deficits. As per present scenario, none of the antiseizure drugs have been reported successful to have ameliorative effect on epilepsy associated depression and cognitive deficits. Thus, the study was envisioned to assess an ameliorative potential of agmatine on epilepsy and its efficacy and safety for management of associated depression and cognitive deficits. The animals were made epileptic employing pentylenetetrazole (35mg/kg i.p. every 48±2h) kindling model of epilepsy and subsequently were treated with vehicle, valproic acid (300mg/kg/day i.p.) and agmatine (2.5, 5, and 10mg/kg)/day/i.p. for 15days. Except naïve, all the groups were challenged with same pentylenetetrazole dose as employed during kindling on days 5, 10, and 15 to evaluate seizure severity. Two hours after seizure severity test, tail suspension test and passive shock avoidance paradigm was employed to evaluate depression and cognitive behavior respectively. Results suggested that epileptic animals were significantly associated with depression and cognitive impairment. Chronic valproate treatment significantly reduced seizure severity, but was found unable to mitigate depression and cognitive deficits. However, agmatine treatment dose dependently ameliorated seizure severity as well as associated depression and cognitive deficits. On 15th day, animals were euthanized and pertinent neurochemical estimations were carried out in cortical and hippocampal areas of the mice brain. Thus, study concluded that agmatine ameliorated seizure severity, depression and cognitive impairment in epileptic animals, possibly via restoring glutamate-GABA neurotransmission and serotonin synthesis with decreased nitrosative stress.

Effect of topiramate and zonisamide on fMRI cognitive networks

OBJECTIVE

To investigate the effects of topiramate (TPM), zonisamide (ZNS), and levetiracetam (LEV) on cognitive network activations in patients with focal epilepsy using an fMRI language task.

METHODS

In a retrospective, cross-sectional study, we identified patients from our clinical database of verbal fluency fMRI studies who were treated with either TPM (n = 32) or ZNS (n = 51). We matched 62 patients for clinical measures who took LEV but not TPM or ZNS. We entered antiepileptic comedications as nuisance variables and compared out-of-scanner psychometric measures for verbal fluency and working memory between groups.

RESULTS

Out-of-scanner psychometric data showed overall poorer performance for TPM compared to ZNS and LEV and poorer working memory performance in ZNS-treated patients compared to LEV-treated patients. We found common fMRI effects in patients taking ZNS and TPM, with decreased activations in cognitive frontal and parietal lobe networks compared to those taking LEV. Impaired deactivation was seen only with TPM.

CONCLUSIONS

Our findings suggest that TPM and ZNS are associated with similar dysfunctions of frontal and parietal cognitive networks, which are associated with impaired performance. TPM is also associated with impaired attenuation of language-associated deactivation. These studies imply medication-specific effects on the functional neuroanatomy of language and working memory networks.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in patients with focal epilepsy, TPM and ZNS compared to LEV lead to disruption of language and working memory networks.

Alteration of Monoamine Receptor Activity and Glucose Metabolism in Pediatric Patients with Anticonvulsant-Induced Cognitive Impairment

A landmark study from the Institute of Medicine reported that the assessment of cognitive difficulties in children with epilepsy is timely and imperative. Anticonvulsant-induced cognitive impairment could influence the quality of life more than seizure itself in patients. Although the monoaminergic system is involved in the regulation of cognitive process, its role in anticonvulsant-induced cognitive impairment remains unclear. Methods: To explore in vivo monoamine receptor binding activity in patients with anticonvulsant-induced cognitive impairment, each patient underwent PET imaging with both monoamine receptor binding agent ¹¹C-N-methylspiperone and glucose metabolic agent ¹⁸F-FDG. Tests of intelligence quotient (IQ), including verbal IQ (VIQ), performance IQ (PIQ), and full-scale IQ (FSIQ), were performed in each patient. Results: Compared with the patients with monotherapy, patients with polytherapy had significantly lower VIQ, PIQ, and FSIQ (P < 0.01 in each comparison), as well as significantly lower monoamine receptor activities detected in the caudate nucleus, prefrontal cortex, dorsal anterior cingulate cortex, and amygdale (P < 0.05 in each comparison). However, regarding the glucose metabolism, there was no significant difference found in patients with monotherapy or polytherapy (P > 0.05). Conclusion: Monoamine receptor PET imaging could be a promising in vivo imaging biomarker for mapping anticonvulsant-induced cognitive impairment.

Effect of pregabalin on fear-based conditioned avoidance learning and spatial learning in a mouse model of scopolamine-induced amnesia

OBJECTIVES

Cognitive deficits are one of the frequent symptoms accompanying epilepsy or its treatment.

METHODS

In this study, the effect on cognition of intraperitoneally administered antiepileptic drug, pregabalin (10 mg/kg), was investigated in scopolamine-induced memory-impaired mice in the passive avoidance task and Morris water maze task. The effect of scopolamine and pregabalin on animals' locomotor activity was also studied.

RESULTS

In the retention phase of the passive avoidance task, pregabalin reversed memory deficits induced by scopolamine (p < 0.05). During the acquisition phase of the Morris water maze pregabalin-treated memory-impaired mice performed the test with longer escape latencies than the vehicle-treated mice (significant at p < 0.05 on Day 5, and at p < 0.001 on Day 6). There were no differences in this parameter between the scopolamine-treated control group and pregabalin-treated memory-impaired mice, which indicated that pregabalin had no influence on spatial learning in this task. During the probe trial a significant difference (p < 0.05) was observed in terms of the mean number of target crossings between vehicle-treated mice and pregabalin-treated memory-impaired mice but there was no difference between the scopolamine-treated control group and mice treated with pregabalin + scopolamine. Pregabalin did not influence locomotor activity increased by scopolamine.

DISCUSSION

In passive avoidance task, pregabalin reversed learning deficits induced by scopolamine. In the Morris water maze, pregabalin did not influence spatial learning deficits induced by scopolamine. These results are relevant for epileptic patients treated with pregabalin and those who use it for other therapeutic indications (anxiety, pain).

Watch the language! Language and linguistic-cognitive abilities in children with nocturnal epileptiform activity

We studied the language and linguistic-cognitive abilities of a group of children with nocturnal epileptiform activity (NEA; N=33) who were hospitalized at a tertiary epilepsy hospital. The children were compared with two groups: one age- and gender-matched group (N=33) and one group matched on language ability (vocabulary) and gender (N=66). We also examined how NEA-related variables affected language abilities. Overall, the children with NEA showed delayed language abilities and a trend for specific difficulties with phonology and naming speed. We did not find firm evidence that the amount of NEA, the use of antiepileptic drugs (AEDs), and the lateralization and localization of NEA had an effect on language. However, we found that children with right-lateralized epileptiform activity seemed to have specific difficulties with naming speed. Additionally, our results indicated that NEA located in the centrotemporal areas particularly affected phonology and orthographic skills.

Diagnosing and treating depression in epilepsy

At least one third of patients with active epilepsy suffer from significant impairment of their emotional well-being. A targeted examination for possible depression (irrespective of any social, financial or personal burdens) can identify patients who may benefit from medical attention and therapeutic support. Reliable screening instruments such as the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) are suitable for the timely identification of patients needing help. Neurologists should be capable of managing mild to moderate comorbid depression but referral to mental health specialists is mandatory in severe and difficult-to-treat depression, or if the patient is acutely suicidal. In terms of the therapeutic approach, it is essential first to optimize seizure control and minimize unwanted antiepileptic drug-related side effects. Psychotherapy for depression in epilepsy (including online self-treatment programs) is underutilized although it has proven effective in ten well-controlled trials. In contrast, the effectiveness of antidepressant drugs for depression in epilepsy is unknown. However, if modern antidepressants are used (e.g. SSRI, SNRI, NaSSA), concerns about an aggravation of seizures and or problematic interactions with antiepileptic drugs seem unwarranted. Epilepsy-related stress ("burden of epilepsy") explains depression in many patients but acute and temporary seizure-related states of depression or suicidality have also been reported. Limbic encephalitits may cause isolated mood alteration without any recognizable psychoetiological background indicating a possible role of neuroinflammation. This review will argue that, overall, a bio-psycho-social model best captures the currently available evidence relating to the etiology and treatment of depression as a comorbidity of epilepsy.

How neuropsychology can improve the care of individual patients with epilepsy. Looking back and into the future

Some of the roots of current clinical neuropsychology go back to the early days of epilepsy surgery. Looking back a huge number of publications have dealt with cognition in epilepsy. The major factors driving this work were questions relating to surgery, antiepileptic drugs and, more recently, also to underlying pathology. However, most factors affecting cognition in epilepsy have been discerned many years ago. The body of neuropsychological literature in this field has accumulated much knowledge, raising the question why, apart from epilepsy surgery settings, neuropsychology has still not been fully integrated in the routine care of patients with epilepsy. This review on the occasion of Seizure's 25th anniversary attempts to summarize clinically relevant diagnostic advances following a question guided, modular, and evidence-based approach. In doing so, we hope to attract the interest of readers to an exciting mode of assessment which does not only have theoretical but also practical relevance. The comorbidities of epilepsy are becoming an increasingly relevant topic. It is now widely accepted that, while epilepsy may be defined by the occurrence of epileptic seizures, these seizures represent only one of several possible sources of cognitive impairment. It is well-established that there are complex interactions between epilepsy, cognition and behavior, and that both seizures and problems with cognition or behavior may result from a common underlying pathology requiring treatment. With this review we aim to demonstrate that neuropsychology can make a highly valuable contribution to the care of individual patients by contributing to the diagnostic process and by serving as a tool for the monitoring of disease and treatment, thereby improving the quality and safety of patient care. On a national, European, and international level, first efforts are being made to homogenize diagnostics across epilepsy centers and countries in order to achieve a common language and core standards. This should improve communication within and outside the speciality, and help to generate the data required to allow the field to make further progress.