Clinical, Cognitive, and Neurophysiologic Correlates of Short-Term Treatment with Carbamazepine, Oxcarbazepine, and Levetiracetam in Healthy Volunteers

Changes in cortical delta power during chronic invasive epilepsy monitoring

OBJECTIVE

Cortical delta band (1-4 Hz) activity is considered a biomarker for states of altered consciousness, with increased delta power observed during anesthesia, sleep, coma, and delirium. The current study sought to characterize delta power following electrode implantation with respect to patient demographics and clinical characteristics as well as type and duration of surgery.

METHODS

Participants were 25 adult neurosurgical patients implanted with intracranial electrodes for clinical monitoring of their epilepsy. Resting state cortical activity was recorded at multiple occasions over the course of the monitoring period. The initial time point was defined as the first recording within 72 h following surgery. Analyses of cortical activity were conducted using a linear mixed effects modeling approach to account for within-participant correlations and between-participant heterogeneity.

RESULTS

Throughout the monitoring period, delta power decreased in frontal, occipital, parietal, and temporal regions, indicating a global phenomenon. By contrast, beta (14-30 Hz) power remained stable. Delta power was higher following surgical cases that required craniotomy compared to stereoelectroencephalography cases. Surgery duration and anesthesia emergence duration were associated with higher delta power. Recordings from depth electrodes showed higher delta power compared to subdural electrodes. No significant effects of patients' age, sex, white blood cell count, antiseizure medication, and opioid medication dosage on postoperative delta power were found.

SIGNIFICANCE

The results are consistent with a postoperative elevation in delta power that resolves over the course of the monitoring period and indicate an association between increased delta power and craniotomy surgery, as well as longer surgery and emergence durations. The current work provides a comprehensive analysis of surgical, clinical, and physiological factors, suggests risk factors, and lays fundamental groundwork for future studies.

Assessment of temporal changes in cognitive effects induced by antiseizure medications in epilepsy patients

OBJECTIVE

Numerous studies have been conducted investigating the effects of antiseizure medications (ASMs) on cognitive functions, and the cognitive side effects of some ASMs have been demonstrated. However, data on whether tolerance to these side effects develops over time is insufficient. The aim of this study is to evaluate the reversibility of cognitive impairments caused by ASMs in patients, utilizing event-related potentials (ERPs) and the Montreal Cognitive Assessment (MoCA) test.

MATERIALS AND METHODS

The single-center prospective study was conducted from July 2022 to August 2023. This study enrolled participants aged 18 to 50 who had been diagnosed with epilepsy and were planning to commence treatment with an antiseizure medication (ASM). The inclusion criteria comprised individuals aged between 18 and 50 years, with a diagnosis of epilepsy, and who were intending to initiate a new ASM as monotherapy. Exclusion criteria encompassed individuals younger than 18 or older than 50 years, those diagnosed with psychogenic non-epileptic seizures, those currently on antiepileptic drugs, and those with cognitive dysfunction or dementia. Before starting treatment, patients were subjected to the MoCA test and ERP measurements by a neurologist. These tests and measurements were repeated at the second and sixth months of treatment.

RESULT

The study included a cohort of 254 participants with a mean age of 32.6 (±14) years. At the second month after starting treatment with carbamazepine (CBZ), zonisamide (ZNS), valproic acid (VPA), and topiramate (TPM), both MoCA and ERP values showed significantly worse cognitive impairment compared to before treatment (p < 0.05). This impairment showed a significant improvement by the sixth month for CBZ, ZNS, and VPA (p < 0.05). Although there was improvement in MoCA and ERP values in patients using TPM, the changes remained statistically significant compared to baseline values (p < 0.05). In patients using levetiracetam, lamotrigine, oxcarbazepine, and lacosamide, cognitive impairment was not statistically significant at either the second or sixth month.

CONCLUSION

This study demonstrated that the detrimental cognitive effects associated with CBZ, VPA, and ZNS could be reversible. Although some improvement was observed over time with TPM, the absence of significant recovery suggests that additional time may be required for a substantial reversal of these effects.

Effects of frequently prescribed antiseizure medications on motor vehicle driving performance: Narrative review based on a tiered approach for the assessment of clinically meaningful driving impairment in the Ministry of Health, Labour, and Welfare guideline

Patients with epilepsy often require long-term treatment with antiseizure medications, and their impact on daily activities, particularly driving, is of significant concern. The recently published "Guideline for Evaluating Effects of Psychotropic Drugs on the Performance to Drive a Motor Vehicle" in Japan provides a framework that can be referred to for not only the evaluation of new drugs but also the reevaluation of approved drugs. This study conducted a literature review regarding the effects of carbamazepine, valproate, lamotrigine, lacosamide, and levetiracetam, which are frequently prescribed for epilepsy, on driving performance following the guideline's tiered evaluation approach. Analyses of pharmacological, pharmacodynamic, and adverse events suggested that these drugs primarily affect arousal function. Driving studies showed that acute administration of carbamazepine, but not chronic monotherapy with carbamazepine, valproate, lamotrigine, and levetiracetam, significantly impairs driving performance. Epidemiological studies have not identified a definitive association between these drugs and traffic accidents. Initial administration of these five antiseizure medications may affect driving performance, warranting special attention, but the influence appears to diminish with continued use. Nevertheless, while long-term administration of these five drugs may not have a clinically meaningful effect on driving performance, safe driving is not guaranteed for each individual patient, and appropriate individualized guidance is important in clinical practice.

Spectral changes in electroencephalography linked to neuroactive medications: A computational pipeline for data mining and analysis

BACKGROUND AND OBJECTIVES

The increasing amount of open-access medical data provides new opportunities to gain clinically relevant information without recruiting new patients. We developed an open-source computational pipeline, that utilizes the publicly available electroencephalographic (EEG) data of the Temple University Hospital to identify EEG profiles associated with the usage of neuroactive medications. It facilitates access to the data and ensures consistency in data processing and analysis, thus reducing the risk of errors and creating comparable and reproducible results. Using this pipeline, we analyze the influence of common neuroactive medications on brain activity.

METHODS

The pipeline is constructed using easily controlled modules. The user defines the medications of interest and comparison groups. The data is downloaded and preprocessed, spectral features are extracted, and statistical group comparison with visualization through a topographic EEG map is performed. The pipeline is adjustable to answer a variety of research questions. Here, the effects of carbamazepine and risperidone were statistically compared with control data and with other medications from the same classes (anticonvulsants and antipsychotics).

RESULTS

The comparison between carbamazepine and the control group showed an increase in absolute and relative power for delta and theta, and a decrease in relative power for alpha, beta, and gamma. Compared to antiseizure medications, carbamazepine showed an increase in alpha and theta for absolute powers, and for relative powers an increase in alpha and theta, and a decrease in gamma and delta. Risperidone compared with the control group showed a decrease in absolute and relative power for alpha and beta and an increase in theta for relative power. Compared to antipsychotic medications, risperidone showed a decrease in delta for absolute powers. These results show good agreement with state-of-the-art research. The database allows to create large groups for many different medications. Additionally, it provides a collection of records labeled as "normal" after expert assessment, which is convenient for the creation of control groups.

CONCLUSIONS

The pipeline allows fast testing of different hypotheses regarding links between medications and EEG spectrum through ecological usage of readily available data. It can be utilized to make informed decisions about the design of new clinical studies.

Effect of Levetiracetam on Cognition: A Systematic Review and Meta-analysis of Double-Blind Randomized Placebo-Controlled Trials

BACKGROUND

Studies have suggested that levetiracetam may help improve cognitive function in patients with epilepsy. Recently, its efficacy in improving cognitive function was reported in patients with amnestic mild cognitive impairment, schizophrenia, and Alzheimer's disease. However, the specific cognitive domains affected and the degree of evidence supporting these effects remain unclear. This systematic review and meta-analysis aimed to explore the effects of levetiracetam on different cognitive domains.

METHODS

This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. We defined our inclusion criteria for the systematic review as: (1) randomized placebo-controlled trials (RCTs) involving human subjects, (2) double-blinded RCTs, and (3) RCTs evaluating the quantitative differences in cognitive function between levetiracetam and placebo. We excluded: (1) non-RCT studies, (2) open-label studies, and (3) RCTs lacking cognitive assessments for either intervention. Two authors independently searched electronic databases, including PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov, from inception until 2 July 2023. The methodological quality of the included studies was assessed using the Cochrane risk of bias tool. Meta-analytic techniques were applied to examine the impact of levetiracetam on cognitive domain tests, with Hedges' g facilitating the comparison with placebo. The domains analyzed comprised multi-domain, executive function, processing speed, working memory, verbal memory/learning (verbal ML), visuospatial memory/learning (visuospatial ML), and language. We used odds ratios to compare the incidence of treatment-emergent adverse events between the groups, including somnolence, fatigue, dizziness, headache, irritability, and cognitive adverse events.

RESULTS

A random-effects model was utilized to perform a meta-analysis of 16 RCTs including 545 participants. Compared with a placebo, levetiracetam was associated with improved executive function [Hedges'g = - 0.390, 95% confidence interval (CI) = - 0.609 to - 0.172, p < 0.001, I2 = 24.0%]. Subgroup analysis showed that levetiracetam outperformed placebo in patients without epilepsy (Hedges' g = - 0.419, 95% CI = - 0.647 to - 0.191, p < 0.001, I2 = 26.2%). Meanwhile, low-dose levetiracetam showed a moderate favorable effect over placebo (Hedges' g = -0.544, 95% CI = - 1.085 to - 0.003, p = 0.049, I2 = 65.3%). In patients without epilepsy, low-dose levetiracetam was associated with improved executive function (Hedges'g = - 0.544, 95% CI = - 1.085 to - 0.003, p = 0.049, I2 = 65.3%). Concurrently, levetiracetam was associated with more frequent somnolence than a placebo (odds ratio = 4.654, 95% CI = 1.533 to 14.124, p = 0.007, I2 = 32.9%). Potential publication bias was observed in the executive function domain.

CONCLUSIONS

This exploratory study suggests that levetiracetam might improve executive function in specific populations. However, the diversity in study populations and potential publication bias warrant caution.

A review of the pharmacology and clinical applications of levetiracetam in dogs and cats

OBJECTIVE

To review and summarize the pharmacology of the antiepileptic drug (AED), levetiracetam (LEV), and to discuss its clinical utility in dogs and cats.

DATA SOURCES

Veterinary and human peer-reviewed medical literature and the authors' clinical experience.

SUMMARY

LEV is an AED with mechanisms of action distinct from those of other AEDs. In people and small animals, LEV exhibits linear kinetics, excellent oral bioavailability, and minimal drug-drug interactions. Serious side effects are rarely reported in any species. LEV use is gaining favor for treating epilepsy in small animals and may have wider clinical applications in patients with portosystemic shunts, neuroglycopenia, and traumatic brain injury. In people, LEV may improve cognitive function in patients with dementia.

CONCLUSION

LEV is a well-tolerated AED with well-documented efficacy in human patients. Although its use is becoming more common in veterinary medicine, its role as a first-line monotherapy in small animal epileptics remains to be determined. This review of the human and animal literature regarding LEV describes its role in epileptic people and animals as well as in other disease states and provides recommendations for clinical usage.

Effect of Oxcarbazepine on Language Function in Patients With Newly Diagnosed Pediatric Epilepsy

BACKGROUND AND PURPOSE

This study aimed to determine the effects of oxcarbazepine (OXC) on the language function of patients with pediatric epilepsy.

METHODS

We assessed the language abilities of patients aged 5-17 years with newly diagnosed focal epilepsy and the same number of age-matched healthy children using the Test of Problem Solving (TOPS) and the Receptive and Expressive Vocabulary Test-Receptive (REVT-R). The Mean Length of Utterance-words (MLU-w) was used to estimate linguistic productivity before and after OXC initiation. All patients received OXC monotherapy with a starting dosage of 10 mg/kg/day for 1 week, which in some cases was increased to 30 mg/kg/day (or 1,200 mg/day).

RESULTS

The study finally included 41 pediatric patients (22 males and 19 females; age 9.9±3.0 years, mean±standard deviation). All language parameters of the TOPS improved significantly after initiating OXC (determining cause, 12.5±4.8-13.7±4.1 [p=0.016]; making inference, 15.6±5.6-17.4±6.4 [p<0.001]; and predicting, 9.8±5.0-11.6±4.5 [p=0.001]). However, patients who received OXC did not exhibit a significantly extended MLU-w (determining cause, p=0.493; making inference, p=0.386; and predicting, p=0.341). Receptive language scores also significantly increased after taking OXC (REVT-R: 121.0±43.1-129.4±43.8, p=0.002), but the percentage of development age to chronological age did not vary (REVT-developmental quotient: p=0.075).

CONCLUSIONS

Our results suggest that OXC is safe and preserves language function in patients with pediatric epilepsy.

E.L., a modern-day Phineas Gage: Revisiting frontal lobe injury

BACKGROUND

How the prefrontal cortex (PFC) recovers its functionality following lesions remains a conundrum. Recent work has uncovered the importance of transient low-frequency oscillatory activity (LFO; < 4 Hz) for the recovery of an injured brain. We aimed to determine whether persistent cortical oscillatory dynamics contribute to brain capability to support 'normal life' following injury.

METHODS

In this 9-year prospective longitudinal study (08/2012-2021), we collected data from the patient E.L., a modern-day Phineas Gage, who suffered from lesions, impacting 11% of his total brain mass, to his right PFC and supplementary motor area after his skull was transfixed by an iron rod. A systematic evaluation of clinical, electrophysiologic, brain imaging, neuropsychological and behavioural testing were used to clarify the clinical significance of relationship between LFO discharge and executive dysfunctions and compare E.L.´s disorders to that attributed to Gage (1848), a landmark in the history of neurology and neuroscience.

FINDINGS

Selective recruitment of the non-injured left hemisphere during execution of unimanual right-hand movements resulted in the emergence of robust LFO, an EEG-detected marker for disconnection of brain areas, in the damaged right hemisphere. In contrast, recruitment of the damaged right hemisphere during contralateral hand movement, resulted in the co-activation of the left hemisphere and decreased right hemisphere LFO to levels of controls enabling performance, suggesting a target for neuromodulation. Similarly, transcranial magnetic stimulation (TMS), used to create a temporary virtual-lesion over E.L.'s healthy hemisphere, disrupted the modulation of contralateral LFO, disturbing behaviour and impairing executive function tasks. In contrast to Gage, reasoning, planning, working memory, social, sexual and family behaviours eluded clinical inspection by decreasing LFO in the delta frequency range during motor and executive functioning.

INTERPRETATION

Our study suggests that modulation of LFO dynamics is an important mechanism by which PFC accommodates neurological injuries, supporting the reports of Gage´s recovery, and represents an attractive target for therapeutic interventions.

FUNDING

Fundação de Amparo Pesquisa Rio de Janeiro (FAPERJ), Universidade Federal do Rio de Janeiro (intramural), and Fiocruz/Ministery of Health (INOVA Fiocruz).

Spontaneous and TMS-related EEG changes as new biomarkers to measure anti-epileptic drug effects

Robust biomarkers for anti-epileptic drugs (AEDs) activity in the human brain are essential to increase the probability of successful drug development. The frequency analysis of electroencephalographic (EEG) activity, either spontaneous or evoked by transcranial magnetic stimulation (TMS-EEG) can provide cortical readouts for AEDs. However, a systematic evaluation of the effect of AEDs on spontaneous oscillations and TMS-related spectral perturbation (TRSP) has not yet been provided. We studied the effects of Lamotrigine, Levetiracetam, and of a novel potassium channel opener (XEN1101) in two groups of healthy volunteers. Levetiracetam suppressed TRSP theta, alpha and beta power, whereas Lamotrigine decreased delta and theta but increased the alpha power. Finally, XEN1101 decreased TRSP delta, theta, alpha and beta power. Resting-state EEG showed a decrease of theta band power after Lamotrigine intake. Levetiracetam increased theta, beta and gamma power, while XEN1101 produced an increase of delta, theta, beta and gamma power. Spontaneous and TMS-related cortical oscillations represent a powerful tool to characterize the effect of AEDs on in vivo brain activity. Spectral fingerprints of specific AEDs should be further investigated to provide robust and objective biomarkers of biological effect in human clinical trials.

Neuropsychological exponents for the driving ability in remitted bipolar patients

Background

Bipolar disorder (BD) is associated with cognitive deficits regardless of the phase of the disease. Medications used in treatment are an additional factor that may affect cognitive performance. Poor cognitive performance can significantly affect a patient's ability to drive.

Aim of the study

This study aims to explore cognitive functions relevant for safe driving in the group of remitted bipolar patients.

Method

Patients with BD in remission (n = 33) and healthy volunteers (n = 32) were included. Selected psychometric tests for drivers were carried out using computer software: called Specialistic Diagnostic Platform (SPD): The Cross-over Test (COT) version with free tempo (COT-F) and tempo of 50 tasks per minute (COT-50) and the Signal Test (ST). Moreover, the following neuropsychological tests were used: Rey Auditory Verbal Learning Test (RAVLT), Stroop Color-Word Test (SCWT) part A and B, and Trail Making Test (TMT) version A and B.

Results

In comparison with healthy controls bipolar patients in remission had poorer outcomes for some cognitive parameters and longer reaction times in both tests for drivers and neuropsychological tests. Additionally, we found a significant correlation between the time of performance of neuropsychological tests and the time of psychometric tests for drivers.

Conclusion

Patients with BD performed worse in several cognitive domains assessed by tests for drivers and neuropsychological tasks. These deficits can affect the speed of the patient's motor reactions while driving.

Clinical and Electroencephalography Assessment of the Effects of Brivaracetam in the Treatment of Drug-Resistant Focal Epilepsy

Introduction: Our aim was to evaluate the clinical and electroencephalographic effects of brivaracetam (BRV) in patients with drug-resistant focal epilepsy. BRV is a new antiepileptic drug (AED) with a high affinity for vesicle protein 2A (SV2A) and recently approved as adjunctive therapy for focal onset seizures. Methods: In this observational study of six-month duration, BRV (50-200 mg) was administered to 76 patients with drug-resistant focal epilepsy, who were ≥16-year-old and who suffered from daily, weekly, monthly and yearly recurrent seizures. At baseline and after six months of follow-up, we performed a neurological visit, neuropsychological tests: Quality of life in epilepsy-31 (QOLIE31), Epworth Sleepiness Scale (ESS), Intrapersonal Emotional Quotient (IEQ) and an electroencephalogram (EEG; inspective and quantitative analysis). Twenty-four patients underwent an overnight switch from levetiracetam (LEV) to BRV. Results: Seizure frequency of the 54 patients remaining at six months was reduced >50% in 29.6% of cases (responders), <50% in 31.5% (non-responders 1), while it remained unchanged in 38.8% (non-responders 2). Twenty-nine percent of patients early discontinued BRV because of lack of efficacy or minor adverse effects (AEs) like irritability, asthenia or headache. Neuropsychological tests in 28 patients demonstrated a significant improvement in I-EPI scores (p=0.04). Comparable results have been found in the subgroup of patients who switched from LEV to BRV. The EEG quantitative analysis showed a significant reduction of alpha absolute power at six months (p=0.03). Theta band power resulted significantly superior in non-responders than in responders (p=0.03). Furthermore, the δ+θ/α+β index resulted more elevated in patients with AEs than in patients without. Conclusions: BRV showed discrete results in terms of efficacy, safety and tolerability, with a good behavioural profile. BRV reduces the power of the alpha band, in correlation with its sedative effects but not with its minor efficacy. Furthermore, the increase in theta band power can be considered as a predictor of scarce response to treatment, while an increase in the δ+θ/α+β index could be a possible predictor of AEs occurrence.

Effects of perampanel on cognition and quantitative electroencephalography in patients with epilepsy

Antiepileptic drugs are well known for their effects on cognition and electrophysiologic changes. However, perampanel is yet to be evaluated for its effects on cognitive function and electroencephalography (EEG). The purpose of the present study was to identify the effect of perampanel on neuropsychological (NP) tests and quantitative EEG (QEEG) and their relationship with the level of the drug in blood. Seventeen patients with epilepsy were enrolled in the study. Electroencephalographic recordings were obtained, and NP tests were conducted before perampanel intake and 6 months after treatment. The relative frequency band power, peak alpha frequency, and NP test scores were compared before and after drug administration. The serum concentration of perampanel was correlated with the QEEG changes. Delayed recall of the Rey Complex Figure showed significant improvement (20.03 vs. 22.94; P = 0.004) following perampanel administration. Other cognitive function tests showed no significant differences before and after drug administration. Theta frequency band power increased in all brain regions (P = 0.001-0.01), and alpha frequency power decreased in all brain regions (P = 0.006-0.03). The theta/alpha ratio, which represents background EEG slowing, increased in all brain areas (P = 0.003-0.02). The peak frequency of the alpha rhythm decreased after perampanel intake (t = 2.45, P = 0.03). Difference of relative alpha power in the central region positively correlated with the blood level of perampanel (r = 0.53, P = 0.03). Perampanel induced electrophysiological slowing, but cognitive decline was not observed. Because the controls were not compared in the study, the results of cognitive function tests should be interpreted conservatively. Background EEG slowing correlated with the serum concentration of perampanel. Our results show the effect of perampanel on cognitive function and background EEG in adult patients with epilepsy.

Event-related potential (P300): the effects of levetiracetam in cognitive performance

BACKGROUND

The current study is a reanalysis in the time domain of EEG data collection in healthy adults during an oddball paradigm using levetiracetam (LEV) vs. placebo acute administration. Specifically, the event-related potential (ERP) technique provides a tool for exploring the EEG responses to a specific event/stimulus. One of the ERP components widely studied is the P300 component, which is associated with the last stage of information processing and a general measurement of "cognitive efficiency."

METHODS

The sample was composed of thirteen healthy right-handed individuals randomized to participate under two conditions: LEV and placebo. Electrophysiological measures were collected before and after drug intake. We explored the oddball paradigm, which is commonly used with healthy individuals to investigate the stages of information processing.

RESULTS

The electrophysiological results showed a main effect of condition on P300 amplitude for the frontal (F3, Fz, F4), central (C3, Cz, C4), and parietal electrodes (P3, Pz, P4). The post hoc comparisons (Scheffé's test) demonstrated the significant differences between electrodes. Regarding P300 latency, all regions represented a main effect of condition. A P300 latency reduction was observed during LEV condition compared with placebo.

CONCLUSION

Our study observed the ERP component-P300-through the variation of its amplitude and latency to evaluate a supposed higher CNS efficiency when participants were under the LEV effect. Our findings sustain this premise, mainly due to reducing in P300 latency for the LEV condition, supporting the neural efficiency hypothesis.

Effects of antiepileptic drugs on electroencephalography (EEG): Insights and applicability

OBJECTIVE

The objective of the study was to assess the effects of antiepileptic drugs (AEDs) on posterior alpha rhythm and determine whether they produce pathological slow waves in patients with epilepsy.

METHODS

Outpatient electroencephalographs (EEGs) in alert patients were selected. The three compared groups include 1) patients with an interested AED (monotherapy or combined with other AEDs); 2) patients with AEDs other than the interested AED; and 3) patients who did not take AEDs. Outcomes were frequency of posterior alpha rhythm and presence of generalized continuous (CSWs) and generalized intermittent slow waves (ISWs). Analysis of variance was used to assess which AED was associated with slower posterior alpha rhythm. Chi-square and logistic regression were employed to assess association and odds ratio (OR) with 95% confidence interval (CI) between pathological generalized slow waves and each AED.

RESULTS

Among 1050 EEG tracings, 638 EEGs met our criteria. Electroencephalographs requested because of cognitive decline and psychiatric symptoms were excluded, leaving 616 EEGs for analysis. Four hundred thirty-seven patients received at least one AED, whereas the remaining 179 patients did not take AED. Conventional AEDs [carbamazepine (CBZ), p = 0.024; phenobarbital (PB), p = 0.013; phenytoin (PHT), p = 0.001] except valproic acid (VPA) were associated with slower alpha frequency. Carbamazepine [adjusted OR: 5.74 (95% CI: 2.07, 15.94)] and PB [adjusted OR: 2.58 (95% CI: 1.15, 5.78)] were significantly associated with generalized ISWs. None were associated with generalized CSWs.

CONCLUSIONS

Phenytoin, CBZ, and PB are associated with slower posterior alpha frequency. The latter 2 AEDs also produced pathological generalized ISWs. Valproic acid, benzodiazepines, and new-generation AEDs are not associated with either outcome. The presence of generalized ISWs in patients taking CBZ or PB should be cautiously interpreted since there can be drug effects. Association with cognitive side effects of these slow waves should be further studied.

Augmenting pharmacotherapy with neuromodulation techniques for the treatment of bipolar disorder: a focus on the effects of mood stabilizers on cortical excitability

Introduction: Mood stabilizers and antipsychotics have been demonstrated to be effective in Bipolar Disorder, with lithium as the gold standard. However, the presence of adverse events and treatment-resistance is still a relevant issue. To this respect, the use of brain stimulation techniques may be considered as an augmentation strategy, with both Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) having shown some level of efficacy in bipolar patients although clinical trials are still not sufficient to draw any conclusion. Areas covered: The authors have conducted a systematic review of the literature, in order to evaluate the role of mood stabilizers on neural activity and cortical excitability. Furthermore, the article reviews neuromodulation techniques and highlights the potential of integrating pharmacological first-line therapies with these techniques to treat BD patients. Expert opinion: The combination of neuromodulation techniques and available pharmacotherapies is a valuable opportunity which is not undermined by specific effects on cortical excitability and could improve BD patient outcome. Neurostimulation techniques may be considered safer than antidepressant treatments in BD, with a lower level of manic switches and may represent a new treatment strategy in BD depressive episodes.

Eslicarbazepine Acetate Modulates EEG Activity and Connectivity in Focal Epilepsy

Introduction: Eslicarbazepine acetate (ESL) is an antiepileptic drug approved as monotherapy or add-on for the treatment of epilepsy with seizures of focal onset. ESL owns a good profile in terms of efficacy and tolerability, but its effects on EEG activity and connectivity are unknown. The purpose of this study was to investigate EEG activity and connectivity changes after ESL treatment in persons with focal epilepsy (PFE).

Material and Methods: We performed a multicentre, longitudinal, retrospective, quantitative EEG study on a population of 22 PFE, and a group of 40 controls. We investigated the ESL-related changes of EEG power spectral activity and global connectivity [phase locking value (PLV), amplitude envelope correlation (AEC) and amplitude envelope correlation of orthogonalized signals (Ortho-AEC)] for standard frequency bands (delta to gamma). Seizure frequency was evaluated to assess ESL efficacy in our cohort.

Results: ESL significantly enhanced both global power spectral density and connectivity for all frequency bands, similarly for all connectivity measures. When compared to the control group, Post-ESL power was significantly higher in theta and gamma band. Pre-ESL connectivity values were significantly lower than control for all frequency bands. Post-ESL connectivity increased and the gap between the two groups was no longer significant. ESL induced a 52.7 ± 41.1% reduction of seizure frequency, with 55% of clinical responders (reduction of seizures ≥50%).

Discussion: ESL therapy induces significant enhancement of brain activity and connectivity. Post-ESL connectivity profile of epilepsy patients was similar to the one of healthy controls.

Neurological and Psychological Changes in Hemodialysis Patients Before and After the Treatment

Neurological, psychological, and cognitive disorders in chronic kidney disease may contribute to poor quality of life in these patients. The aim of this study was to assess the electroencephalographic, psychological, and cognitive changes before and after hemodialysis (HD) compared with healthy controls (HC). Sixteen HD patients and 15 HC were enrolled. Electroencephalogram (EEG), Minnesota multiphasic personality inventory (MMPI-2) Satisfaction profile (SAT-P), and Neuropsychological test Global z-scores (NPZ5) were performed before (T0) and after (T1) HD treatment and in HC. Renal function, inflammatory markers and mineral metabolism indexes were also evaluated. Patients did not show significant differences before and after HD in the absolute and relative power of band of EEG, except in Theta/Alpha index (P < 0.001). At T1, HD patients showed significant differences in Beta, Delta and Theta band, in addition to Theta/alpha index, with respect to HC. Moreover, HD patients showed significant differences in specific MMPI-2 clinical and content scales, SAT-P domains and NPZ5 tests of memory and concentration with respect to HC. We also observed significant correlations between renal function, mineral metabolism, inflammatory markers and psychocognitive alterations. In our sample EEG abnormalities tend to reduce, but not significantly, after HD treatment and differences remain present with respect to HC. In HD patients cognitive and psychological alterations were associated with reduced quality of life and correlated with mineral metabolism and inflammation. Modification in EEG and in psychological and cognitive parameters should be assessed in a larger HD population to confirm our observation.

Levetiracetam Alters Oscillatory Connectivity in Alzheimer's Disease

Seizures occur at a higher frequency in people with Alzheimer's disease (AD) but overt, clinically obvious events are infrequent. Evidence from animal models and studies in mild cognitive impairment suggest that subclinical epileptic discharges may play a role in the clinical and pathophysiological manifestations of AD. In this feasibility study, the neurophysiological and cognitive effects of acute administration of levetiracetam (LEV) are measured in patients with mild AD to test whether it could have a therapeutic benefit. AD participants were administered low dose LEV (2.5 mg/kg), higher dose LEV (7.5 mg/kg), or placebo in a double-blind, within-subject repeated measures study with EEG recorded at rest before and after administration. After administration of higher dose of LEV, we found significant decreases in coherence in the delta band (1-3.99 Hz) and increases in the low beta (13-17.99 Hz) and the high beta band (24-29.99 Hz). Furthermore, we found trends toward increased power in the frontal and central regions in the high beta band (24-29.99 Hz). However, there were no significant changes in cognitive performance after this single dose administration. The pattern of decreased coherence in the lower frequency bands and increased coherence in the higher frequency bands suggests a beneficial effect of LEV for patients with AD. Larger longitudinal studies and studies with healthy age-matched controls are needed to determine whether this represents a relative normalization of EEG patterns, whether it is unique to AD as compared to normal aging, and whether longer term administration is associated with a beneficial clinical effect.

Eslicarbazepine acetate in the treatment of adults with partial-onset epilepsy: an evidence-based review of efficacy, safety and place in therapy

INTRODUCTION

Up to 30% of the patients diagnosed with epilepsy will continue suffering from seizures despite treatment with antiepileptic drugs, either in monotherapy or polytherapy. Hence, there remains the need to develop new effective and well-tolerated therapies.

AIM

The objective of this article was to review the evidence for the efficacy and safety of eslicarbazepine acetate (ESL) as adjunctive treatment in adult patients with focal onset seizures.

EVIDENCE REVIEW

ESL is the newest, third-generation, single enantiomer member of the dibenzazepine family. Following oral administration, ESL is rapidly and extensively metabolized by hepatic first-pass hydrolysis to the active metabolite eslicarbazepine, which has linear, dose-proportional pharmacokinetics and low potential for drug-drug interactions. Eslicarbazepine works as a competitive blocker of the voltage gated sodium channels; unlike carbamazepine (CBZ) and oxcarbazepine (OXC), it has a lower affinity for the resting state of the channels, and reduces their availability by selectively enhancing slow inactivation. Efficacy and safety of ESL have been assessed in four randomized, Phase III clinical trials: the median relative reduction in standardized seizure frequency was 33.4% and 37.8% in the ESL 800 and 1,200 mg daily dose groups, and the responder rates were 33.8% and 43.1%, respectively. The incidence of treatment-emergent adverse events (TEAEs) increased with raising the dosage (ESL 400 mg: 63.8%, ESL 800 mg: 67.0%, ESL 1,200 mg: 73.1%). The TEAEs were generally mild to moderate in intensity, and the most common were dizziness, somnolence, headache and nausea. Open-label studies confirmed the findings from the pivotal trials and demonstrated sustained therapeutic effect of ESL over time and improvement of tolerability profile in patients switching from OXC/CBZ. No unexpected safety signals emerged over >5 years of follow-up.

CONCLUSION

Once-daily adjunctive ESL at the doses of 800 and 1,200 mg was effective to reduce the seizure frequency and was fairly well tolerated in adults with focal onset epilepsy. Starting treatment at 400 mg/day, followed by 400 mg increments every 7-14 days, could provide the optimal balance of efficacy and tolerability.

A randomized, double-blind, placebo-controlled crossover study of the effects of levetiracetam on cognition, mood, and balance in healthy older adults

OBJECTIVE

The cognitive and mood effects of levetiracetam (LEV) in older adults are not known. This study compared the cognitive and mood effects of LEV to placebo in healthy older adults.

METHODS

Cognitive, mood, and balance variables were compared between LEV and placebo using a randomized, double-blind, placebo-controlled crossover study with two 5-week treatment periods. Healthy volunteers (n = 20) aged 65-80 (mean age 72.4) received either LEV or placebo in which the LEV target dose was 1,000 mg/day. Volunteers, aged 65-80, were without epilepsy to limit potentially confounding the impact of seizures and/or underlying neuropathology on outcomes. LEV was initiated at 250 mg twice a day for 2 weeks, then increased to 500 mg twice a day for 2 weeks, and then tapered to 250 mg twice a day for 1 week. This was randomized with placebo for the two treatment arms. Measures included standardized neuropsychological, mood, and balance tests yielding 32 variables. Balance was assessed using subjective report (e.g., A-B neurotoxicity scale) and objective data (e.g., Berg Balance Scale).

RESULTS

Average LEV serum concentration was 16.9 (standard deviation [SD} 7.7). Repeated-measures analysis of variance (ANOVA) found no differences between LEV and placebo phases for 29 (90.6%) of 32 variables including no change in balance. Performance on LEV was better than placebo on a visual memory (MCG Complex Figure Recall; p = 0.007) and two attention tests (Trail Making Test, Part A, p = 0.009; Stroop Interference, p = 0.004). There was a trend for greater irritability and fatigue (POMS Anger and Fatigue) during the LEV phase (p = 0.029, p = 0.035). Effect-size changes were generally small (Cohen d < 0.5).

SIGNIFICANCE

LEV was well tolerated in this elderly population in terms of cognition, mood, and balance. When anticonvulsant medication is indicated for older adults, LEV has pharmacokinetic advantages, and these data indicate no adverse impact on cognition or balance.

Managing aggression in epilepsy

Behavioural changes associated with epilepsy can be challenging for patients and clinicians. Evidence suggests an association between aggression and epilepsy that involves various neurophysiological and neurochemical disturbances. Anti-epileptics have variable effects on behaviour and cognition that need consideration. Early detection and careful consideration of history, symptomatology and possible common comorbid psychiatric disorders is essential. Appropriate investigations should be considered to aid diagnosis, including electroencephalogram (EEG), video EEG telemetry and brain imaging. Optimising treatment of epilepsy, treatment of psychiatric comorbidities and behavioural management can have a major positive effect on patients' recovery and well-being.

Learning Objectives

• Understand the epidemiology of aggression in epilepsy

• Comprehend the link between anti-epileptics and aggression, including the important role of pharmacodynamics

• Be aware of the pharmacological treatments available for managing aggressive behaviour in epilepsy

Seizure response to perampanel in drug-resistant epilepsy with gliomas: early observations

Drug-resistant epilepsy (DRE) occurs commonly in gliomas, possibly due to a shared mechanism of AMPA-activation involving both seizure activity and tumor growth. We tested the AMPA-receptor blocker perampanel (PER) in patients with DRE in low- and high-grade gliomas. Seizure response was defined as 50% drop in seizure frequency or as seizure-freedom. Cognitive function was examined by computerized test on cognitive speed (CTCS), which is sensitive to the type of cognitive dysfunction associated with epilepsy and use of anticonvulsants. Treatment policy included reduction of dose or discontinuation of one or more concurrent AEDs, once a seizure-free response was observed. Twelve patients were included patients, median age 41 years, 9 men versus 3 women and 6 months median duration of follow-up. An objective seizure response (75%) was observed in 9 (75%) out of 12 patients: 50%-seizure response in 3, seizure-freedom in 6, which is plainly more than seen with other types of DRE. Side-effects occurred in six patients. Cognitive function as examined by CTCS improved in six out of eight associated withlowering of concurrent AEDs. The final median dose of PER was 8 mg (varying between 2 and 12 mg). These results of an objective seizure response in 9 (75%) out of 12 patients treated by PER in DRE may be interpreted as a surrogate-marker of tumor response secondary to AMPA blockade, advancing confirmation by MR imaging. These results warrant further study of PER on tumor activity in gliomas.

Slow Activity in Focal Epilepsy During Sleep and Wakefulness

INTRODUCTION

We aimed to test differences between healthy subjects and patients with respect to slow wave activity during wakefulness and sleep.

METHODS

Fifteen patients affected by nonlesional focal epilepsy originating within temporal areas and fourteen matched controls underwent a 24-hour EEG recording. We studied the EEG power spectral density during wakefulness and sleep in delta (1-4 Hz), theta (5-7 Hz), alpha (8-11 Hz), sigma (12-15 Hz), and beta (16-20 Hz) bands.

RESULTS

During sleep, patients with focal epilepsy showed higher power from delta to beta frequency bands compared with controls. The effect was widespread for alpha band and above, while localized over the affected hemisphere for delta (sleep cycle 1, P = .006; sleep cycle 2, P = .008; sleep cycle 3, P = .017). The analysis of interhemispheric differences showed that the only frequency band stronger over the affected regions was the delta band during the first 2 sleep cycles (sleep cycle 1, P = .014; sleep cycle 2, P = .002). During wakefulness, patients showed higher delta/theta activity over the affected regions compared with controls.

CONCLUSIONS

Patients with focal epilepsy showed a pattern of power increases characterized by a selective slow wave activity enhancement over the epileptic regions during daytime and sleep. This phenomenon was stronger and asymmetric during the first sleep cycles.

Neurological, psychological, and cognitive disorders in patients with chronic kidney disease on conservative and replacement therapy

Chronic kidney disease (CKD) is a highly prevalent condition in the world. Neurological, psychological, and cognitive disorders, related to CKD, could contribute to the morbidity, mortality, and poor quality of life of these patients. The aim of this study was to assess the neurological, psychological, and cognitive imbalance in patients with CKD on conservative and replacement therapy.Seventy-four clinically stable patients affected by CKD on conservative therapy, replacement therapy (hemodialysis (HD), peritoneal dialysis (PD)), or with kidney transplantation (KT) and 25 healthy controls (HC), matched for age and sex were enrolled. Clinical, laboratory, and instrumental examinations, as renal function, inflammation and mineral metabolism indexes, electroencephalogram (EEG), psychological (MMPI-2, Sat P), and cognitive tests (neuropsychological tests, NPZ5) were carried out.The results showed a significant differences in the absolute and relative power of delta band and relative power of theta band of EEG (P = 0.008, P < 0.001, P = 0.051), a positive correlation between relative power of delta band and C-reactive protein (CRP) (P < 0.001) and a negative correlation between estimated glomerular filtration rate (eGFR) (P < 0.001) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) (P < 0.001), in all the samples. Qualitative analysis of EEG showed alterations of Grade 2 (according to Parsons-Smith classification) in patients on conservative therapy, and Grade 2-3 in KT patients. The scales of MMPI-2 hysteria and paranoia, are significantly correlated with creatinine, eGFR, serum nitrogen, CRP, 1,25-(OH)2D3, intact parathyroid hormone (iPTH), phosphorus, and cynical and hysterical personality, are correlated with higher relative power of delta (P = 0.016) and theta band (P = 0.016). Moreover, all NPZ5 scores showed a significant difference between the means of nephropathic patients and the means of the HC, and a positive correlation with eGFR, serum nitrogen, CRP, iPTH, and vitamin D.In CKD patients, simple and noninvasive instruments, as EEG, and cognitive-psychological tests, should be performed and careful and constant monitoring of renal risk factors, probably involved in neuropsychological complications (inflammation, disorders of mineral metabolism, electrolyte disorders, etc.), should be carried out. Early identification and adequate therapy of neuropsychological, and cognitive disorders, might enable a better quality of life and a major compliance with a probable reduction in the healthcare costs.

Behavioral effects and somnolence due to levetiracetam versus oxcarbazepine - a retrospective comparison study of North Indian patients with refractory epilepsy

PURPOSE

Levetiracetam (LEV) is often chosen early in the treatment of refractory epilepsy; however, its adverse effects have largely been studied as part of clinical trials. Oxcarbazepine and valproate (VPA) are the other commonly used AEDs and, hence, serve as good comparators. This study was conducted to evaluate behavioral abnormalities and somnolence among patients with epilepsy being treated with LEV and/or OXC compared with those receiving VPA.

METHOD

Data of consecutive patients attending our intractable epilepsy clinic over a 2 1/2-year period were reviewed, and patients with at least one seizure a month, who had been initiated on either or a combination of LEV, VPA, or OXC, were included for analysis. Data regarding behavioral adverse effects, daytime somnolence (EDS), and weight changes were collected apart from those regarding any major effect necessitating dose reduction or discontinuation of the AED.

RESULTS

Among a total of 445 patients screened, 292 (93 F, median age: 21years [range: 8-54]; 237 focal and 55 generalized epilepsy) fulfilled inclusion criteria. Median epilepsy duration was 11years. Levetiracetam had been introduced in 114 patients, VPA in 134, and OXC in 151 during the study period. Twenty-three were on LEV+OXC, 27 on LEV+VPA, and 33 on VPA+OXC. Behavioral disturbances (irritability, obsessive manifestations, aggressiveness, and frank psychosis) were observed in 43 patients; 23 on introduction of LEV (20.2%); LEV was discontinued in 10 (9%). Daytime somnolence was reported by 28 patients, 15 on OXC (10%); 8 received oral modafinil for the same, while none discontinued this AED. Only one patient on LEV and 3 on VPA reported EDS. Menstrual disturbances were reported by 9, weight gain by 3, and severe hair loss by 2 females on VPA.

CONCLUSION

Behavioral disturbances with levetiracetam are common among patients with refractory epilepsy while somnolence is common with oxcarbazepine. Antiepileptic drugs should be selected with this in perspective.

The influence of levetiracetam in cognitive performance in healthy individuals: neuropsychological, behavioral and electrophysiological approach

OBJECTIVE

The present study sought to analyze the influence of Levetiracetam (LEV) in cognitive performance by identifying the changes produced by LEV in reaction time, in neuropsychological assessment of attention and memory and in absolute theta power in frontal activity.

METHODS

Twelve healthy subjects (5 men and 7 women; mean age, 30.08 years, standard deviation, 4.71) were recruited for this study. The neuropsychological tests: Trail Making Test (A and B), Digit Span (direct and indirect numerical orders/working memory); Stroop test (inhibitory control of attention); Tower of London (planning and decision-making) and a quantitative electroencephalography were applied in 2 different days after and before the participants ingested the capsule of placebo or 500 mg LEV.

RESULTS

A two-way-ANOVA was implemented to observe the interaction between conditions (placebo or LEV 500 mg) and moments (pre- and post-ingestion of LEV or placebo). The data were analyzed by the SPSS statistical package (p<0.05). For the neuropsychological parameter, the Trail Making Test (A) was the only test that showed significant difference for condition in the task execution time (p=0.026). Regarding the reaction time in the behavioral parameter, an interaction between both factors (p=0.034) was identified through a two-way-ANOVA (condition versus moment). Electrophysiological measures showed a significant interaction for electrodes: F7, F3, and FZ.

CONCLUSIONS

The findings showed that LEV promotes an important cognitive enhancement in the executive functions.

Effect of oxcarbazepine on background EEG activity and cognition in epilepsy

BACKGROUND AND PURPOSE

Cognitive dysfunction related to antiepileptic drugs (AEDs) is an important issue in the management of patients with epilepsy. The aim of the present study was to evaluate relative long-term effects of oxcarbazepine (OXC) on cognition in drug-naive patients with epilepsy.

METHODS

Fifteen drug-naïve epilepsy patients were enrolled. Electroencephalogram (EEG) recordings and neuropsychological (NP) tests were performed before and after OXC monotherapy. The relative power of the discrete frequency bandwas obtained. In addition, interhemispheric and intrahemispheric spectral coherence was also calculated.

RESULTS

NP tests showed significant improvement in visuo-spatial, memory and executive function after OXC treatment. However, neither spectral power nor coherence changed significantly with OXC treatment.

CONCLUSIONS

Our study supports the notion that OXC has no significant cognitive side effect in patients with epilepsy.

Levetiracetam improves verbal memory in high-grade glioma patients

BACKGROUND

Treatment of high-grade glioma (HGG) patients with anti-epileptic drugs (AEDs) has met with various side effects, such as cognitive deterioration. The cognitive effects of both older and newer AEDs in HGG patients are largely unknown. The aim of this study was to determine the effect of older and newer AEDs on cognitive performance in postoperative HGG patients.

METHODS

We selected HGG patients from 3 separate cohorts for use of older, newer, or no AEDs, as they represented distinct treatment eras and provided the opportunity to compare older and newer AEDs. In all 3 cohorts, patients were included within 6 weeks following neurosurgery before the start of postoperative treatment. Cognitive functioning was evaluated by an extensive neuropsychological assessment, executed in 6 cognitive domains (attention, executive functioning, verbal memory, working memory, psychomotor functioning, and information processing speed).

RESULTS

One hundred seventeen patients met the inclusion criteria; 44 patients used no AED, 35 were on monotherapy with a newer AED (all levetiracetam), and 38 were on monotherapy with an older AED (valproic acid or phenytoin). Patients on older and newer AEDs performed equally well as patients not on an AED, and patients on levetiracetam performed even better on verbal memory tests than patients not on an AED. Post-hoc analyses revealed that within the group using older AEDs, patients on valproic acid performed better than patients on phenytoin.

CONCLUSIONS

Neither levetiracetam nor valproic acid was associated with additional cognitive deficits in HGG patients. Both AEDs even appeared to have a beneficial effect on verbal memory in these patients.

Polarity-dependent effect of low-frequency stimulation on amygdaloid kindling in rats

BACKGROUND

Low-frequency stimulation (LFS, <5 Hz) has been proposed as an alternative option for the treatment of epilepsy. The stimulation pole, anode and cathode, may make different contributions to the anti-epileptic effect of LFS.

OBJECTIVE

To determine whether electrode polarity influences the anti-epileptic effect of LFS at the kindling focus in amygdaloid kindling rats.

METHODS

The effect of bipolar and monopolar (or unipolar) LFS at the amygdala in different polarity directions on amygdaloid kindling acquisition, kindled seizures and electroencephalogram (EEG) were tested.

RESULTS

Bipolar LFS in the same direction of polarity as the kindling stimulation but not in the reverse direction retarded kindling acquisition. Anodal rather than cathodal monopolar LFS attenuated kindling acquisition and kindled seizures. Bipolar LFS showed a stronger anti-epileptic effect than monopolar LFS. Furthermore, anodal LFS (both bipolar and monopolar) decreased, while cathodal LFS increased the power of the EEG from the amygdala; the main changes in power were in the delta (0.5-4 Hz) band, which was specifically increased during kindling acquisition.

CONCLUSIONS

Our results provide the first evidence that the effect of LFS at the kindling focus on amygdaloid kindling in rats is polarity-dependent, and this may be due to the different effects of anodal and cathodal LFS on the activity in the amygdala, especially on the delta band activity. So, It is likely that the electrode polarity, especially that for anodal current, is a key factor affecting the clinical effects of LFS on epilepsy.

Psychiatric symptomatologies and disorders related to epilepsy and antiepileptic medications

INTRODUCTION

Psychiatric comorbidities (such as depression, anxiety, psychosis, inattention, obsession, personality traits, aggression and suicide) are frequent in patients with epilepsy and have a significant impact on medical management and quality of life.

AREAS COVERED

A literature search was performed in MEDLINE for epidemiological, longitudinal, prospective, double-blind clinical trial studies published between 1990 and 2011 using the following words: epilepsy, antiepileptic drugs (AEDs), behavioral/emotional/psychiatric comorbidities, suicide and aggression. In this review, the author discusses: i) the characterization and prevalence of behavioral disturbances associated with epilepsy, ii) variables correlated with behavioral comorbidities which include: psychosocial-, clinical- and treatment-related variables, iii) the complex mechanisms of behavioral comorbidities associated with epilepsy, which include both psychosocial (functional) and organic; the process of epileptogenesis, neuronal plasticity, abnormalities in hypothalamic-pituitary axis and neurotransmitters and pathways are fundamental determinants, iv) the negative psychotropic effects of AEDs and their mechanisms and v) the suggested biopsychosocial model of management (pharmacological and non-pharmacological).

EXPERT OPINION

The relationship between psychiatric disorders and epilepsy has relevant therapeutic implications which should be directed towards a comprehensive biopsychosocial approach that focuses on the whole person rather than simply on the disease process.

Effect of levetiracetam monotherapy on background EEG activity and cognition in drug-naïve epilepsy patients

OBJECTIVE

To investigate the cognitive effect of levetiracetam (LEV) monotherapy with quantitative electroencephalogram (EEG) analysis and neuropsychological (NP) tests.

METHODS

Twenty-two drug-naïve epilepsy patients were enrolled. EEG recordings were performed before and after LEV therapy. Relative power of discrete frequency bands was computed, as well as alpha peak frequency (APF) at occipital electrodes. Eighteen patients performed a battery of NP tests twice across LEV treatment.

RESULTS

LEV therapy decreased the power of delta (1-3 Hz, p<0.01) and theta (3-7 Hz, p<0.05) bands and increased that of alpha-2 (10-13 Hz, p<0.05) and beta-2 (19-24 Hz, p<0.05) bands. Region-specific spectral change was observed: delta power change was significant in fronto-polar region, theta in anterior region, alpha-2 in broad region, and beta-2 in left fronto-central region. APF change was not significant. Improvement in diverse NP tests requiring attention, working memory, language and executive function was observed. Change in theta, alpha-2, and beta-2 power was correlated with improvement in several NP tests.

CONCLUSIONS

Our data suggest LEV is associated with acceleration of background EEG frequencies and improved cognitive function. Change in frequency band power could predict improvement in several cognitive domains across LEV therapy.

SIGNIFICANCE

Combined study of quantitative EEG analysis and NP tests can be useful in identifying cognitive effect of antiepileptic drugs.

Combined neuropsychological and neurophysiological assessment of drug effects on groups and individuals

An initial standardized approach for combining neuropsychological and neurophysiological measures in order to assess the neurocognitive effects of drugs in groups and individuals is introduced. Its application is illustrated with sedatives, antiepileptic drugs, psychostimulants, antihistamines, and intoxicants. Task performance, electroencephalography, and evoked potential measures during computerized attention and memory testing that are most sensitive to drug effects are identified in a sample population and then applied to individuals. In six example exploratory studies, drug effects were detected with an average area under curve (AUC) of 0.97 (p < 0.0001; 95% sensitivity, 96% specificity). In 10 example validation studies with other drugs and/or different subjects and populations, detection was strong in the eight studies with drugs and doses known to have significant neurocognitive effects (AUC 0.83, p < 0.0001; 82% sensitivity, 89% specificity), whereas no effect was detected in the two studies with drugs known to have faint neurocognitive effects (AUC 0.56, p > 0.10). Individual differences in response to different drugs with similar clinical uses, to varying doses of the same drug, and in pharmacodynamic response were then demonstrated. The significant (p < 0.01) increase in sensitivity and specificity of combined neuropsychological and neurophysiological measures compared with the former alone suggests that fewer subjects may be needed to assess the neurocognitive effects of drugs in future studies. The findings suggest that the concept of combining neuropsychological testing with simultaneous measures of neurophysiological function is worth further exploration.

Reduced movement-related β desynchronisation in juvenile myoclonic epilepsy: a MEG study of task specific cortical modulation

OBJECTIVE

We investigated differences in task induced responses in occipital and sensorimotor cortex between patients with juvenile myclonic epilepsy (JME) and healthy controls .

METHODS

Twelve patients with JME and 12 age-matched non-epilepsy volunteers performed visual and motor tasks during MEG. We used synthetic aperture magnetometry to localise areas of task-related oscillatory modulations, performed time-frequency analyses on the locations of peak task related power changes and compared power and frequency modulation at these locations between patients and controls.

RESULTS

Patients with JME had significantly reduced pre-movement beta event-related desynchronisation in the motor task compared to controls. No significant differences were seen in other motor-related responses, or visual oscillatory responses.

CONCLUSIONS

Altered beta event-related desynchronisation may represent network specific dysfunction in JME possibly through GABAergic dysfunction.

SIGNIFICANCE

Characterising task specific cortical responses in epilepsy offers the potential to understand the patho-physiological basis of seizures and provide a window on disease and treatment effects.

Prophylactic antibiotics and anticonvulsants in neurosurgery

The prophylactic administration of antibiotics to prevent infection and the prophylactic administration of anticonvulsants to prevent first seizure episodes are common practice in neurosurgery. If prophylactic medication therapy is not indicated, the patient not only incurs the discomfort and the inconvenience resulting from drug treatment but is also unnecessarily exposed to adverse drug reactions, and incurs extra costs. The main situations in which prophylactic anticonvulsants and antibiotics are used are described and those situations we found controversial in the literature and lack further investigation are identified: anticonvulsants for preventing seizures in patients with chronic subdural hematomas, antiepileptic drugs for preventing seizures in those suffering from brain tumors, antibiotic prophylaxis for preventing meningitis in patients with basilar skull fractures, and antibiotic prophylaxis for the surgical introduction of intracranial ventricular shunts.In the following we present systematic reviews of the literature in accordance with the standard protocol of The Cochrane Collaboration to evaluate the effectiveness of the use of these prophylactic medications in the situations mentioned. Our goal was to efficiently integrate valid information and provide a basis for rational decision-making.

Cognitive outcome of antiepileptic treatment with levetiracetam versus carbamazepine monotherapy: a non-interventional surveillance trial

This open-label, non-interventional, controlled surveillance study evaluated the cognitive outcome of patients administered levetiracetam (LEV) or carbamazepine (CBZ) monotherapy as primary treatment or as substitution for previous treatment. Executive functions, verbal memory, and subjective ratings were assessed before and 6 months after initiation of LEV or CBZ monotherapy. Analyses included 498 patients: 370 received LEV (63% pretreated), and 128 CBZ (34% pretreated). Mostly because of the substitution condition, the seizure freedom rate was slightly higher with LEV as opposed to CBZ (78% vs 69%). Almost all cognitive measures improved with LEV but not with CBZ, and repeated-measures MANOVA did not indicate seizure control or pretreatment as decisive with respect to cognitive change. With LEV, executive functions improved in 15% and deteriorated in 5% of patients; the opposite pattern was seen under CBZ (improvement with LEV OR=2.3, deterioration with CBZ OR=3.4). The findings suggest a mild but definitely superior cognitive outcome with LEV as opposed to CBZ monotherapy.

Effects of the antiepileptic drugs on peripheral nerve function

OBJECTIVE

We aimed to compare the effects of antiepileptic drugs and provide findings of peripheral nerve impairment using standard electrophysiological techniques.

MATERIALS AND METHODS

Young adult outpatients with epilepsy on monotherapy for no less than 6 months with carbamazepine (CBZ), valproic acid (VPA), oxcarbazepine (OXC) and topiramate (TPM) were examined. Patients who had any other disease that could effect nerve conduction studies and who had neuropathic symptoms were excluded.

RESULTS

Each group contained 15 patients and 20 healthy subjects were examined as the control group. Prolonged latency of median sensory nerve (P = 0.004), ulnar sensory nerve (P = 0.01) and sural nerve (P = 0.003) with a diminished nerve conduction velocity was observed in the CBZ group (P = 0.014, P = 0.002, P = 0.025, respectively). No correlation was found between VPA, OXC and TPM and the nerve conduction studies (P > 0.05).

CONCLUSIONS

Valproic acid, oxcarbazepine and topiramate don't have effects on nerve conduction studies. Mild electrophysiological changes contribute to carbamazepine therapy.

Comparative study of five antiepileptic drugs on a translational cognitive measure in the rat: relationship to antiepileptic property

RATIONALE

Antiepileptic drugs (AEDs) have been available for many years; yet, new members of this class continue to be identified and developed due to the limitations of existing drugs, which include a propensity for cognitive impairment. However, there is little preclinical information about the cognitive effects they produce, which clinically include deficits in attention and slowing of reaction time.

OBJECTIVES

The purpose of this study was to profile two first-generation AEDs, phenytoin and valproate, and three second-generation AEDs, levetiracetam, pregabalin and lacosamide. Initially, each drug was examined across a range of well characterised preclinical seizure tests, and then each drug was evaluated in the five-choice serial reaction time test (5-CSRTT) based on efficacious doses from the seizure tests.

MATERIALS AND METHODS

Each AED was tested for anti-seizure efficacy in either (1) the maximal electroshock seizure test, (2) s.c. PTZ seizure test, (3) amygdala-kindled seizures and (4) the genetic absence epilepsy rat of Strasbourg model of absence seizures. On completion of these studies, each drug was tested in rats trained to asymptotic performance in the 5-CSRTT (0.5 s SD, 5 s ITI, 100 trials). Male rats were used in all studies.

RESULTS

Each AED was active in at least one of the seizure tests, although only valproate was active in each test. In the 5-CSRT test, all drugs with the exception of levetiracetam, significantly slowed reaction time and increased omissions. Variable effects were seen on accuracy. The effect on omissions was reversed by increasing stimulus duration from 0.5 to 5 s, supporting a drug-induced attention deficit. Levetiracetam had no negative effect on performance; indeed, reaction time was slightly increased (i.e. faster).

CONCLUSIONS

These results highlight somewhat similar effects of phenytoin, valproate, pregabalin and lacosamide on attention and reaction time, and comparison to efficacious doses from the seizure tests support the view that there may be a better separation with the newer AEDs. Levetiracetam had no detrimental effect in the 5-CSRTT, which may be consistent with clinical experience where the drug is considered to be well tolerated amongst the AED class.

Increased EEG current-source density in the high Beta frequency band induced by levetiracetam adjunctive therapy in refractory partial epilepsy

Background and Purpose

Levetiracetam (LEV) is an antiepileptic drug (AED) that has favorable effects on cognition. Although neuropsychological studies have demonstrated these favorable outcomes on cognition, there are few electrophysiologic data describing the functional changes exerted by LEV. The purpose of this study was to determine the effects of LEV adjunctive therapy on the current-source density (CSD) in the high beta frequency band (22-30 Hz) of EEG background activity in refractory partial epilepsy (RPE).

Methods

We conducted a 24-week, open-label, prospective study in 24 patients with RPE. Scalp electroencephalography and neuropsychological tests (NPTs) were conducted twice, once before the LEV trial and then again after 24 weeks of medication.

Results

The CSD in the 22-30 Hz band of EEG background activity increased in the bilateral anterior cingulate gyri, left parahippocampal gyrus, and a small area of the right anterior parahippocampal gyrus after the LEV trial. Neither seizure freedom nor the dosage increment of LEV elicited meaningful CSD changes. Verbal memory and executive function were improved after the 24-week LEV trial.

Conclusions

To our knowledge, this is the first study to examine the changes in CSD induced by LEV adjunctive therapy in RPE patients. The CSD changes and NPT results suggest that LEV enhances the activities of the neuronal networks in the prefrontal cortex and left hippocampus.

Neuropsychological effects of antiepileptic drugs (carbamazepine versus valproate) in adult males with epilepsy

PURPOSE

To evaluate the effect of antiepileptic drugs (AEDs) on cognition and behavior in adult epileptic males controlled on treatment with conventional antiepileptic medications.

METHODS

Cognitive, mood, behavior and personality traits were assessed in 45 epileptic patients treated with carbamazepine and/or valproate and free of seizures for >/=1 year. Thirty-four newly diagnosed or untreated patients with epilepsy and 58 matched healthy subjects were also included for comparison. A battery of psychometric tests was utilized including Stanford-Binet (4th edition), Beck Inventory for Depression, Aggressive Scale and Eysenck Personality Questionnaire.

RESULTS

Compared to matched control subjects, treated and untreated epileptic patients had poor performance in different cognitive and behavioral functions testing. Treated patients had worse scores in memory for digits forward and backward, total short-term memory, extroversion and psychosis. The duration of AEDs intake was correlated with memory of objects (r = -0.323; P = 0.030), bead memory (r = -0.314; P = 0.036) and total nonverbal short-term memory (r = -0.346; P = 0.020). Treated and untreated epileptic patients had poor performance of similar extent in behavioral functions testing (depression, aggression and neurosis). The dose of AEDs was correlated with testing scores for neurosis (r = 0.307; P = 0.040), verbal aggression (r = 0.483; P = 0.001) and nonverbal aggression (r = 0.526; P = 0.000), and duration of drug intake was correlated with scores for depression (r = 0.384; P = 0.009), psychosis (r = 0.586; P = 0.0001) and nonverbal aggression (r = 0.300; P = 0.045).

CONCLUSIONS

This study provides support for the notion that AEDs can impair performance in cognition, mood and behavior. Duration of drug intake and the number of the utilized AEDs are the main confounding variables. This study did not provide clues on how to exclude the effect of epilepsy itself and psychosocial variables as additional important confounding variables.

Cognitive disorders associated with epilepsy: diagnosis and treatment

INTRODUCTION

Cognitive disorders are common in patients with epilepsy. Their aetiology is multifactorial, being affected by the type and location of the epileptogenic lesion, epileptic syndrome, type of seizures, age of onset, frequency and severity. Timely diagnosis and treatment can help to reduce their impact on the patient's quality of life.

RESULTS

The most significant cognitive deficits are associated with focal epilepsy, although some, usually mild, neuropsychological disorders can be found in idiopathic generalized epilepsy. The use of antiepileptic drugs (AEDs) can cause additional neuropsychological disorders that are of particular concern in learning-age children and elderly patients with cognitive disorders before the start of treatment. Recent studies have raised the concern that the use of some AEDs during pregnancy may cause cognitive disorders in the child exposed to them in utero. Cognitive disorders can also present as a complication of surgery for refractory epilepsy. Some risk factors for significant memory loss after surgery for temporal lobe epilepsy have been described. They include intervention in the dominant hemisphere, good preoperative function and poor functional reserve in the contralateral hippocampus.

CONCLUSIONS

The heterogeneity of different types of epilepsy makes case-control studies difficult; however, thanks to the growing interest in the neuropsychological deficits associated with epilepsy, we now know some factors that could lead to the appearance of these disorders and their prognosis. Special care must be taken to detect cognitive side effects associated with AEDs, which seem to be more common with classic than with new AEDs, and in those patients receiving polytherapy. Neuropsychological assessment should be routinely performed before epilepsy surgery to predict possible postsurgical cognitive deficits.

The aspects and mechanisms of cognitive alterations in epilepsy: the role of antiepileptic medications

Epilepsy is a major health problem. Several studies suggest a significant influence of epilepsy and its treatment on dynamic and functional properties of brain activity. Epilepsy can adversely affect mental development, cognition, and behavior. Epileptic patients may experience reduced intelligence, attention, and problems in memory, language, and frontal executive functions. Neuropsychological, functional, and quantitative neuroimaging studies revealed that epilepsy affect the brain as a whole. Mechanisms of epilepsy-related cognitive dysfunction are poorly delineated. Cognitive deficits with epilepsy may be transient, persistent, or progressive. Transient disruption of cognitive encoding processes may occur with paroxysmal focal or generalized epileptic discharges, whereas epileptogenesis-related neuronal plasticity, reorganization, sprouting, and impairment of cellular metabolism are fundamental determinants for progressive cognitive deterioration. Also antiepileptic drugs (AEDs) have differential, reversible, and sometimes cumulative cognitive adverse consequences. AEDs not only reduce neuronal irritability but also may impair neuronal excitability, neurotransmitter release, enzymes, and factors critical for information processing and memory. The present article serves as an overview of recent studies in adult and childhood epilepsy literatures present in PubMed that highlighted cognitive evaluation in epilepsy field (publications till 2008 were checked). We also checked the reference lists of the retrieved studies for additional reports of relevant studies, in addition to our experience in this field. Our search revealed that although the aspects of cognitive dysfunction, risk factors, and consequences have been explored in many studies; however, the mechanisms of contribution of epilepsy-related variables, including AEDs, to patients' cognition are largely unexplored. In this review, we discussed the differential effect of AEDs in mature and immature brains and the known mechanisms underlying epilepsy and AEDs adverse effects on cognition. The nature, timing, course, and mechanisms of cognitive alteration with epilepsy and its medications are of considerable clinical and research implications.

The effects of levetiracetam on cognition: a non-interventional surveillance study

Objective and subjective cognitive measures were evaluated in 401 patients before and 3 and 6 months after introducing levetiracetam (LEV). Initially, cognitive impairment was indicated in 37-44% of the patients, and subjective impairments in 32-67%. With LEV, 87% of untreated patients changed to monotherapy, and 94% changed from mono- to polytherapy. The rate of retention of LEV was 97%; adverse events were reported by 7%. Under LEV, 36% achieved early seizure control, 25% achieved late seizure control, 33% continued to have seizures, and 7% had a relapse. Very good tolerance was reported by 68%, and cognitive improvement by 58%. Objective improvement was significant in 23-29% of the patients; 5-6% deteriorated. Better baseline scores, later-onset epilepsies, fewer initial antiepileptic drugs, and seizure control were predictive of a better cognitive outcome. Considering the uncontrolled study design and the increase in total drug load, LEV appeared safe and efficacious, and a general subjective and objective cognitive improvement could be noted. However, a controlled study design would be required to attribute these improvements to a specific drug action.

The cognitive effects of oxcarbazepine versus carbamazepine or valproate in newly diagnosed children with partial seizures

OBJECTIVE

To investigate the effect of oxcarbazepine against standard antiepileptic drug therapy (carbamazepine and valproate) on cognitive function in children and adolescents (aged 6 to <17 years) with newly diagnosed partial seizures.

METHODS

A multicentre, open-label, randomised, active-control, three-arm, parallel-group, 6-month study. The primary cognitive variable, the Computerized Visual Searching Task (CVST), assessed mental information processing speed and attention. Secondary variables included additional tests assessing psychomotor speed, alertness, memory and learning, and non-verbal intelligence.

RESULTS

Of 112 patients randomised, 99 completed the study. The dropout rate was 11.6%; 13 patients discontinued due to adverse events (n=5) or unsatisfactory therapeutic effect (n=8). Mean CVST time decreased in all groups, indicating an improvement of mental processing speed and no cognitive impairment in any treatment group. No statistically significant difference was observed between oxcarbazepine and combined carbamazepine/valproate. Analysis of secondary variables did not show statistically significant differences between oxcarbazepine, carbamazepine and valproate. Analysis of intelligence test results showed that the number of correct answers increased at end point in all groups. The percentage of patients remaining seizure free throughout treatment was comparable across all groups (oxcarbazepine 58%; carbamazepine 46%; valproate 54%; carbamazepine/valproate 50%). The most common adverse events were fatigue and headache for oxcarbazepine, fatigue and rash for carbamazepine, and headache, increased appetite and alopecia for valproate.

CONCLUSION

Oxcarbazepine treatment over 6 months does not display any differential effects on cognitive function and intelligence in children and adolescents with newly diagnosed partial seizures relative to standard antiepileptic drug therapy. No impairment in cognitive function was observed in any treatment group over a 6-month period.

Neurocognitive costs and benefits of psychotropic medications in older adults

Psychotropic medications are widely used in older adults and may cause neurocognitive deficits. Older adults are at increased risk of developing adverse effects because of age-related pharmacodynamic and pharmacokinetic changes. This article provides a comprehensive review of the undesirable, and at times beneficial, effects of psychotropic medications. The review covers a wide range of medications that impair executive function, memory, and attention, as well as a much smaller group of medications that lead to improved neurocognitive function. Some of the most commonly used psychotropic medications in older adults, namely, antidepressants, sedatives, and hypnotics, are among the drugs that most consistently lead to cognitive impairments. Medications with anticholinergic properties almost invariably lead to neurocognitive dysfunction, despite symptom improvement. The neurocognitive costs and benefits of psychiatric medications should be considered in the context of disease treatment in older adults.

Association between response inhibition and working memory in adult ADHD: a link to right frontal cortex pathology?

BACKGROUND

We sought to assess the relationship between response inhibition and working memory in adult patients with attention-deficit/hyperactivity disorder (ADHD) and neurosurgical patients with frontal lobe damage.

METHODS

The stop-signal reaction time (SSRT) test and a spatial working memory (SWM) task were administered to 20 adult patients with ADHD and a group of matched controls. The same tasks were administered to 21 patients with lesions to right frontal cortex and 19 patients with left frontal lesions.

RESULTS

The SSRT test, but not choice reaction time, was significantly associated with search errors on the SWM task in both the adult ADHD and right frontal patients. In the right frontal patients, impaired performance on both variables was correlated with the volume of damage to the inferior frontal gyrus.

CONCLUSIONS

Response inhibition and working memory impairments in ADHD may stem from a common pathologic process rather than being distinct deficits. Such pathology could relate to right frontal-cortex abnormalities in ADHD, consistent with prior reports, as well as with the demonstration here of a significant association between SSRT and SWM in right frontal patients.