The effect of topiramate plasma concentration on linguistic behavior, verbal recall and working memory

Drug-Induced Cognitive Impairment

Drug-induced cognitive impairment (DICI) is a well-established, yet under-recognised, complication of many types of pharmacological treatment. While there is a large body of scientific literature on DICI, most papers are about drug-induced dementia in the elderly and one specific drug class. However, DICI also comprises subclinical symptoms, domain-specific forms of cognitive impairment as well as mild cognitive impairment (MCI), and delirium. Even mild forms of DICI, if not recognised as such, can have deleterious and life-long consequences. In addition, DICI also occurs in younger adults and in children, and has been reported with many different drug classes. The aim of this review is to raise awareness of DICI by providing an overview on the type(s) and symptoms of observed DICI and the suspected underlying mechanism(s) for various drug classes: antiseizure medications, antidepressants, antiparkinsonian drugs, antipsychotics, lithium, benzodiazepines/Z-drugs, opioids, first-generation antihistamines, drugs for urinary incontinence, proton pump inhibitors, glucocorticoids, NSAIDs, statins, antihypertensives, and chemotherapeutic agents.

Topiramate promotes osteogenic differentiation through AMPK-dependent phosphorylation of Smad1/5/9

Topiramate [2,3:4,5-bis-o-(1-methylethylidene) β-D-fructo-pyranose sulfamate; TPM] is one of the most used new-generation antiepileptic drugs. It has been reported to regulate the differentiation of human bone cells. However, the molecular mechanism of TPM in osteoblast differentiation is not fully elucidated. In the present study, we examined the effect of TPM on osteogenic differentiation of C3H10T1/2, MC3T3-E1, primary mouse calvarial cells, and primary bone marrow stem cells (BMSCs). Primary cells were isolated from mice calvaria and bone marrow respectively. Expression of the osteogenic gene was determined by RT-PCR. The osteogenic protein levels were measured by Western blot analysis. Alkaline phosphatase (ALP) staining experiment was performed to evaluate ALP activity. Alizarin red s (ARS) staining was performed to measure zebrafish caudal fin regeneration. Treatment of TPM up-regulated the osteogenic genes including distal-less homeobox 5 (Dlx5) and runt-related transcription factor 2 (Runx2). In addition, TPM also increased the Dlx5 and Runx2 protein levels, Smad1/5/9 phosphorylation, and alkaline phosphatase (ALP) activity. Furthermore, TPM activated AMPK, and inhibition of AMPK decreased TPM-induced osteogenic differentiation. In the zebrafish model, osteogenic effect of TPM was identified. TPM was increased amputated caudal fin rays of zebrafish. These results demonstrate that TPM enhances osteogenic differentiation via AMPK-mediated Smad1/5/9 phosphorylation.

Preparation and evaluation of bilayer-core osmotic pump tablets contained topiramate

Topiramate (TPM) was an antiepileptic agent commonly used in clinical. Studies showed that an oral preparation of TPM with extended-release manner could bring some benefits for epileptics. In this paper, controlled release push-pull osmotic pump (PPOP) tablets of sparingly water-soluble TPM were successfully prepared. This bi-layer tablet core mainly consisted of sodium chloride as osmotic promoting agent and polyethylene oxide as suspending and pushing agents. The influences of osmotic agents, pushing agents and the compositions of coating membrane on TPM release profiles were evaluated. An optimal formulation of TPM-PPOP was obtained through single-factor experiments. In vitro release tests showed that the optimum formulation could release TPM at an approximate zero-order rate up to 8 h. Pharmacokinetic behaviors of TPM-PPOP tablets were evaluated and compared with the immediate release capsules after an oral single dose in beagle dogs. Pharmacokinetics results demonstrated that the TPM-PPOP tablet was able to provide a prolonged release of TPM with longer tmax and mean residence time. Lower fluctuations of drug plasma levels could also be achieved with TPM-PPOP tablets. These results suggested that sparely water-soluble drugs as TPM can be designed to PPOP for efficacy and safety use.

An association between resting state EEG parameters and the severity of topiramate-related cognitive impairment

INTRODUCTION

Many commonly prescribed drugs cause cognitive deficits. We investigated whether parameters of the resting-state electroencephalogram (rsEEG) are related to the severity of cognitive impairments associated with administration of the antiseizure drug topiramate (TPM) and the benzodiazepine lorazepam (LZP).

METHODS

We conducted a double-blind, randomized, placebo-controlled crossover study. After a baseline visit, subjects completed three sessions at which they received either a single dose of TPM, LZP, or placebo. Four-hours after drug administration and at baseline, subjects completed a working memory (WM) task after their rsEEG was recorded. After quantifying drug-related behavioral (WM accuracy (ACC)/reaction time (RT)) and electrophysiological (alpha, theta, beta (1,2), gamma power) change for each subject, we constructed drug-specific mixed effects models of change for each WM and EEG measure. Regression models were constructed to characterize the relationship between baseline rsEEG measures and drug-related performance changes.

RESULTS

Linear mixed effects models showed theta power increases in response to TPM administration. The results of the regression models revealed a number of robust relationships between baseline rsEEG parameters and TPM-related, but not LZP-related, WM impairment.

CONCLUSIONS

We showed for the first time that parameters of the rsEEG are associated with the severity of TPM-related WM deficits; this suggests that rsEEG measures may have novel clinical applications in the future.

Severity of Topiramate-Related Working Memory Impairment Is Modulated by Plasma Concentration and Working Memory Capacity

Drug side effects that impair cognition can lead to diminished quality of life and discontinuation of therapy. Topiramate is an antiepileptic drug that elicits cognitive deficits more frequently than other antiepileptic drugs, impairing multiple cognitive domains including language, attention, and memory. Although up to 40% of individuals taking topiramate may experience cognitive deficits, we are currently unable to predict which individuals will be most severely affected before administration. The objective of this study was to show the contributions of plasma concentration and working memory capacity in determining the severity of an individual's topiramate-related cognitive impairment. Subjects were enrolled in a double-blind, placebo-controlled crossover study during which they received a single dose of either 100, 150, or 200 mg topiramate. Working memory function was assessed using a modified Sternberg working memory task with 3 memory loads administered 4 hours after dosing. After adjustment for differences in working memory capacity, each 1 μg/mL of topiramate plasma concentration was associated with a 3.6% decrease in accuracy for all memory loads. Placebo effects occurred as a function of working memory capacity, with individuals with high working memory capacity experiencing less severe placebo-related impairment compared with those with low working memory capacity. Our results demonstrate that severity of topiramate-related cognitive deficits occurs as a function of both drug exposure and baseline cognitive function. By identifying patient- and exposure-related characteristics that modulate the severity of cognitive side effects, topiramate dosing strategies may be individually tailored in the future to prevent unwanted cognitive impairment.

Working Memory Capacity Is Negatively Associated with Memory Load Modulation of Alpha Oscillations in Retention of Verbal Working Memory

Working memory capacity (WMC) measures the amount of information that can be maintained online in the face of distraction. Past work has shown that the efficiency with which the frontostriatal circuit filters out task-irrelevant distracting information is positively correlated with WMC. Recent work has demonstrated a role of posterior alpha oscillations (8-13 Hz) in providing a sensory gating mechanism. We investigated the relationship between memory load modulation of alpha power and WMC in two verbal working memory experiments. In both experiments, we found that posterior alpha power increased with memory load during memory, in agreement with previous reports. Across individuals, the degree of alpha power modulation by memory load was negatively associated with WMC, namely, the higher the WMC, the less alpha power was modulated by memory load. After the administration of topiramate, a drug known to affect alpha oscillations and have a negative impact on working memory function, the negative correlation between memory load modulation of alpha power and WMC was no longer statistically significant but still somewhat detectable. These results suggest that (1) individuals with low WMC demonstrate stronger alpha power modulation by memory load, reflecting possibly an increased reliance on sensory gating to suppress task-irrelevant information in these individuals, in contrast to their high WMC counterparts who rely more on frontal areas to perform this function and (2) this negative association between memory load modulation of alpha oscillations and WMC is vulnerable to drug-related cognitive disruption.

Brain's compensatory response to drug-induced cognitive impairment

INTRODUCTION

Topiramate (TPM), a frequently prescribed antiseizure medication, can cause severe cognitive side-effects. Though these side-effects have been studied behaviorally, the underlying neural mechanisms are unknown. In a double-blind, randomized, placebo-controlled, crossover study of TPM's impact on cognition, nine healthy volunteers completed three study sessions: a no-drug baseline session and two sessions during which they received either TPM or placebo. Electroencephalogram was recorded during each session while subjects performed a working-memory task with three memory-loads.

RESULTS

Comparing TPM with baseline we found the following results. (a) TPM administration led to declines in behavioral performance. (b) Fronto-central event-related potentials (ERP) elicited by probe stimuli, representing the primary task network activity, showed strong memory-load modulations at baseline, but the magnitude of these load-dependent modulations was significantly reduced during TPM session, suggesting drug-induced impairments of the primary task network. (c) ERP responses over bilateral fronto-temporal electrodes, which were not load sensitive at baseline, showed significant memory-load modulations after TPM administration, suggesting the drug-related recruitment of additional neural resources. (d) At fronto-central scalp sites, there was significant increase in response amplitude for low memory-load during TPM session compared to baseline, and the amplitude increase was dependent on TPM plasma concentration, suggesting that the primary task network became less efficient under TPM impact. (e) At bilateral fronto-temporal electrodes, there were no ERP differences when comparing low memory-load trials, but TPM administration led to an increase in ERP responses to high load, the magnitude of which was positively correlated with task performance, suggesting that the recruited neural resources were beneficial for task performance. Placebo-TPM comparison yielded similar effects albeit with generally reduced significance and effect sizes.

CONCLUSION

Our findings support the hypothesis that TPM impairs the primary task network by reducing its efficiency, which triggers compensatory recruitment of additional resources to maintain task performance.

Individual Differences in Working Memory Capacity Predict Topiramate-Related Cognitive Deficits

PURPOSE/BACKGROUND

Topiramate (TPM) and lorazepam (LZP) are two examples of frequently prescribed medications that are associated with a high incidence of cognitive impairment; however, the factors that underlie interindividual differences in side effect profiles have not been fully characterized. Our objective was to determine whether working memory capacity (WMC), the amount of information that can be stored and manipulated in memory over short time intervals, is one such factor.

METHODS/PROCEDURES

Twenty-nine healthy volunteers completed a double-blind, randomized, placebo-controlled crossover study during which they received placebo (PBO), TPM, and LZP in random order. Four hours after drug administration, a blood draw was taken to establish drug concentrations, and subjects performed a verbal working memory task while the accuracy and reaction time of their responses were recorded. Working memory capacity was calculated based on accuracy rates during the PBO session, and the role of WMC in moderating the severity of drug-related cognitive impairment was assessed by examining drug-related performance changes from PBO as a function of WMC.

FINDINGS/RESULTS

Both TPM and LZP had a negative impact on task performance, although only TPM-related deficits were modulated by WMC; high WMC was associated with more severe impairments and heightened sensitivity to increasing TPM concentrations.

IMPLICATIONS/CONCLUSIONS

We have identified a potential clinical risk factor, high WMC, which is associated with drug-related adverse cognitive events. These data provide objective evidence in support of clinical observations that high-functioning patients are more likely to experience severe cognitive impairments.

Real-world assessment of treatment with extended-release topiramate (Trokendi XR®) and comparison with previous immediate-release topiramate treatment

AIM

Examine clinical profile of extended-release topiramate (Trokendi XR^®) and compare treatment-emergent adverse events (TEAEs) associated with Trokendi XR versus previous immediate-release topiramate (TPM-IR) treatment.

PATIENTS & METHODS

Pilot retrospective study analyzing data extracted from medical charts of patients ≥6 years of age prescribed Trokendi XR.

RESULTS

Trokendi XR was the most commonly used to prevent migraine. The most common TEAEs recorded during topiramate treatment were cognitive symptoms (word-finding difficulty, attention/concentration difficulty, slowed thinking), paresthesia, gastrointestinal problems and decreased appetite/weight loss. TEAE incidence was significantly (p < 0.001) lower during Trokendi XR versus previous TPM-IR treatment.

CONCLUSION

Trokendi XR use and outcomes in clinical practice were consistent with established profile of topiramate. Results supported the potential for better tolerability of Trokendi XR versus TPM-IR.

Refining the Benefit/Risk Profile of Anti-Epileptic Drugs in Headache Disorders

Anti-epileptic drugs are among the most effective drugs for migraine prophylaxis, and will likely continue to have a role even as new therapies emerge. Topiramate and valproate are effective for the preventive treatment of migraine, and other medications such as gabapentin or lamotrigine may have a role in the treatment of those with allodynia or frequent aura, respectively. Oxcarbazepine, carbamazepine, phenytoin, gabapentin, and others may alleviate pain in trigeminal neuralgia. While many anti-epileptic drugs can be effective in those with migraine or other headaches, most of these agents can potentially cause serious side effects. In particular, valproate, topiramate, carbamazepine, and phenytoin may lead to adverse outcomes for infants of exposed mothers. Valproate should not be given to women of childbearing potential for migraine prevention.

Effects of low-dose topiramate on language function in children with migraine

Purpose

This study aimed to verify the safety of low-dose topiramate on language development in pediatric patients with migraine.

Methods

Thirty newly diagnosed pediatric patients with migraine who needed topiramate were enrolled and assessed twice with standard language tests, including the Test of Language Problem Solving Abilities (TOPs), Receptive and Expressive Vocabulary Test, Urimal Test of Articulation and Phonology, and computerized speech laboratory analysis. Data were collected before treatment, and topiramate as monotherapy was sustained for at least 3 months. The mean follow-up period was 4.3±2.7 months. The mean topiramate dosage was 0.9 mg/kg/day.

Results

The patient's mean age was 144.1±42.3 months (male-to-female ratio, 9:21). The values of all the language parameters of the TOPs were not changed significantly after the topiramate treatment as follows: Determine cause, from 15.0±4.4 to 15.4±4.8 (P>0.05); making inference, from 17.6±5.6 to 17.5±6.6 (P>0.05); predicting, from 11.5±4.5 to 12.3±4.0 (P>0.05); and total TOPs score, from 44.1± 13.4 to 45.3±13.6 (P>0.05). The total mean length of utterance in words during the test decreased from 44.1±13.4 to 45.3±13.6 (P<0.05). The Receptive and Expressive Vocabulary Test results decreased from 97.7±22.1 to 96.3±19.9 months, and from 81.8±23.4 to 82.3±25.4 months, respectively (P>0.05). In the articulation and phonology validation in both groups, speech pitch and energy were not significant, and all the vowel test results showed no other significant values.

Conclusion

No significant difference was found in the language-speaking ability between the patients; however, the number of vocabularies used decreased. Therefore, topiramate should be used cautiously for children with migraine.

Topiramate in Migraine Prevention: A 2016 Perspective

BACKGROUND

In evidence-based guidelines published in 2000, topiramate was a third-tier migraine preventive with no scientific evidence of efficacy; recommendation for its use reflected consensus opinion and clinical experience. Its neurostabilizing activity, coupled with its favorable weight profile, made topiramate an attractive alternative to other migraine preventives that caused weight gain. When guidelines for migraine prevention in episodic migraine were published in 2012, topiramate was included as a first-line option based on double-blind, randomized controlled trials involving nearly 3000 patients. The scientific and clinical interest in topiramate has generated a large body of data from randomized controlled trials, meta-analyses, patient registries, cohort studies, and claims data analyses that have more fully characterized its role as a migraine preventive.

AIM

This article will review the profile of topiramate that has emerged out of the past decade of research and clinical use in migraine prophylaxis. It will also address the rationale for extended-release (XR) formulations in optimizing topiramate therapy in migraine.

SUMMARY

Topiramate has activity at multiple molecular targets, which may account for why it is effective in migraine and most other, more specific, anticonvulsants are not. Based on randomized controlled trials, topiramate reduces migraine frequency and acute medication use, improves quality of life, and reduces disability in patients with episodic migraine and in those with chronic migraine with or without medication overuse headache. Its efficacy in chronic migraine is not improved by the addition of propranolol. Topiramate's ability to prevent progression from high-frequency episodic migraine to chronic migraine remains unclear. Consistent with clinicians' perceptions, migraineurs are more sensitive to topiramate-associated side effects than patients with epilepsy. Paresthesia is a common occurrence early in treatment but is rarely cause for terminating topiramate treatment. Cognitive problems occur much less frequently than paresthesia but are more troublesome in terms of treatment discontinuation. Cognitive complaints can often be managed by slowly increasing the topiramate dose in small increments to allow habituation. As with other carbonic anhydrase inhibitors, topiramate has metabolic effects that favor the development of metabolic acidosis and possibly renal stones. Because migraineurs have an increased risk of renal stones independent of topiramate exposure, clinicians should counsel all migraine patients to maintain hydration. Abrupt onset of blurring, other visual disturbances, and/or ocular pain following topiramate's initiation should be evaluated promptly since this may indicate rare but potentially sight-threatening idiosyncratic events. Postmarketing evidence has shown that first-trimester exposure to topiramate monotherapy is associated with increased occurrence of cleft lip with or without cleft palate (Pregnancy Category D). Even though topiramate's long half-life would seemingly support q.d. dosing, randomized controlled migraine trials used b.i.d. administration of immediate-release (IR) topiramate, which has more favorable plasma concentration-time profile (ie, lower peak concentrations and higher trough concentrations) than q.d. IR dosing. Given the sensitivity of migraineurs to topiramate-related adverse events, particularly cognitive effects, pharmacokinetic profiles should be considered when optimizing migraine outcomes. The extended-release (XR) formulations Qudexy^® XR (Upsher-Smith Laboratories) and Trokendi XR^® (Supernus Pharmaceuticals) were specifically designed to achieve the adherence benefits of q.d. dosing but with more favorable (ie, more constant) steady-state plasma concentrations over the 24-hour dosing interval vs IR topiramate b.i.d. Intriguing results from a study in healthy volunteers showed consistently less impairment in neuropsychometric tests of verbal fluency and mental processing speed with an XR topiramate formulation (Trokendi XR) vs IR topiramate b.i.d. These findings suggest a pharmacodynamic effect associated with significantly reducing plasma concentration fluctuation when topiramate absorption is slowed. Results of retrospective studies in migraineurs treated with XR topiramate appear to support a clinically meaningful benefit of XR topiramate vs IR topiramate in terms of significantly fewer cognitive effects, improved adherence, and overall better outcomes of migraine prophylaxis with topiramate.

Use of an automated mobile application to assess effects of nicotine withdrawal on verbal fluency: A pilot study

Mild-to-moderate impairment in frontally mediated functions such as sustained attention, working memory, and inhibition have been found to occur during tobacco withdrawal and may present a barrier to successful cessation. These findings have led to studies evaluating cessation treatments that target nicotine withdrawal related cognitive impairment. The instruments currently used to assess cognitive function provide detailed and specific information but have limitations including being time consuming, cumbersome, anxiety provoking, and having poor ecological validity. The authors examined the feasibility of using a mobile computer application to test verbal fluency (VF) as a quick, easy-to-administer, and more ecologically valid method of measuring the effects of short-term smoking abstinence on frontally mediated cognitive functions. Thirty participants completed 2 assessments-1 during ad lib smoking and 1 after overnight abstinence. At each assessment, semantic and phonemic VF tests were administered using a mobile application and nicotine craving and withdrawal symptom severity was assessed. In repeated assessments, performance on both semantic and phonemic VF tests is expected to improve due to practice effects; however, significant improvements were observed only in semantic (p = .012) but not phonemic (p = .154) VF. In addition, the change between assessments in phonemic (but not semantic) score was significantly associated with withdrawal (p = .006) and craving (p = .037) severity measured postabstinence. This study demonstrates that nicotine withdrawal has differential effects on semantic versus phonemic VF suggesting impairments of working memory, attention, and inhibition. These effects were measured using methods easily used in large groups of participants, potentially with remote test administration and automated scoring. (PsycINFO Database Record

Pharmacokinetic-pharmacodynamic modelling of intravenous and oral topiramate and its effect on phonemic fluency in adult healthy volunteers

AIMS

The aim was to develop a quantitative approach that characterizes the magnitude of and variability in phonemic generative fluency scores as measured by the Controlled Oral Word Association (COWA) test in healthy volunteers after administration of an oral and a novel intravenous (IV) formulation of topiramate (TPM).

METHODS

Nonlinear mixed-effects modelling was used to describe the plasma TPM concentrations resulting from oral or IV administration. A pharmacokinetic-pharmacodynamic (PK-PD) model was developed sequentially to characterize the effect of TPM concentrations on COWA with different distributional assumptions.

RESULTS

Topiramate was rapidly absorbed, with a median time to maximal concentration of 1 h and an oral bioavailability of ~100%. Baseline COWA score increased by an average of 12% after the third administration on drug-free sessions. An exponential model described the decline of COWA scores, which decreased by 14.5% for each 1 mg l(-1) increase in TPM concentration. The COWA scores were described equally well by both continuous normal and Poisson distributions.

CONCLUSIONS

This analysis quantified the effect of TPM exposure on generative verbal fluency as measured by COWA. Repetitive administration of COWA resulted in a better performance, possibly due to a learning effect. The model predicts a 27% reduction in the COWA score at the average observed maximal plasma concentration after a 100 mg dose of TPM. The single-dose administration of relatively low TPM doses and narrow range of resultant concentrations in our study were limitations to investigating the PK-PD relationship at higher TPM exposures. Hence, the findings may not be readily generalized to the broader patient population.

Pharmacokinetic-Pharmacodynamic Modeling of Intravenous and Oral Topiramate and Its Effect on the Symbol-Digit Modalities Test in Adult Healthy Volunteers

A sequential pharmacokinetic-pharmacodynamic (PK-PD) modeling approach was used to quantify the effects of a single dose of topiramate (100 or 200 mg) on working memory, attention, and psychomotor speed as measured by the Symbol-Digit Modalities Test (SDMT). Established on data pooled from 3 randomized, crossover studies in healthy subjects (19-55 years of age), using both oral and a novel stable-labeled intravenous (IV) formulation of topiramate, an inhibitory Emax model was found to characterize the topiramate concentration-SDMT score relationship well. At the EC50 of 2.85 μg/mL, this topiramate plasma concentration value was estimated to be associated with a 25.5% reduction of SDMT score relative to baseline. Age was an important determinant of the baseline SDMT score, with an estimated decrease of 1.13% in baseline SDMT score with every year of age. Moreover, this approach enabled the quantification of the practice effect observed with repeated administration of the neuropsychological test over shorter testing intervals than have previously been reported in the literature. The finding of a significant effect following a single dose of topiramate in the range widely used to treat migraine and epilepsy needs to be evaluated in a broader patient population undergoing chronic treatment, as the narrow range of resultant concentrations limits the generalizability of the findings.

Using Automatic Speech Recognition to Assess Spoken Responses to Cognitive Tests of Semantic Verbal Fluency

Cognitive tests of verbal fluency (VF) consist of verbalizing as many words as possible in one minute that either start with a specific letter of the alphabet or belong to a specific semantic category. These tests are widely used in neurological, psychiatric, mental health, and school settings and their validity for clinical applications has been extensively demonstrated. However, VF tests are currently administered and scored manually making them too cumbersome to use, particularly for longitudinal cognitive monitoring in large populations. The objective of the current study was to determine if automatic speech recognition (ASR) could be used for computerized administration and scoring of VF tests. We examined established techniques for constraining language modeling to a predefined vocabulary from a specific semantic category (e.g., animals). We also experimented with post-processing ASR output with confidence scoring, as well as with using speaker adaptation to improve automated VF scoring. Audio responses to a VF task were collected from 38 novice and experienced professional fighters (boxing and mixed martial arts) participating in a longitudinal study of effects of repetitive head trauma on brain function. Word error rate, correlation with manual word count and distance from manual word count were used to compare ASR-based approaches to scoring to each other and to the manually scored reference standard. Our study's results show that responses to the VF task contain a large number of extraneous utterances and noise that lead to relatively poor baseline ASR performance. However, we also found that speaker adaptation combined with confidence scoring significantly improves all three metrics and can enable use of ASR for reliable estimates of the traditional manual VF scores.

Long-lasting recognition memory impairment and alterations in brain levels of cytokines and BDNF induced by maternal deprivation: effects of valproic acid and topiramate

Exposure to stressful events early in life may have permanent deleterious consequences on nervous system function and increase the susceptibility to psychiatric conditions later in life. Maternal deprivation, commonly used as a source of neonatal stress, impairs memory in adult rats and reduces hippocampal brain-derived neurotrophic factor (BDNF) levels. Inflammatory cytokines, such as interleukins (IL) and tumor necrosis factor-α (TNF-α) have been shown to be increased in the peripheral blood of patients with psychiatric disorders. The aim of the present study was to investigate the effects of maternal separation on the levels of IL-10 and TNF-α, and BDNF in the hippocampus and prefrontal cortex of adult rats. We also evaluated the potential ameliorating properties of topiramate and valproic acid on memory deficits and cytokine and BDNF changes associated with maternal deprivation. The results indicated that, in addition to inducing memory deficits, maternal deprivation increased the levels of IL-10 in the hippocampus, and TNF-α in the hippocampus and in the cortex, and decreased hippocampal levels of BDNF, in adult life. Neither valproic acid nor topiramate were able to ameliorate memory deficits or the reduction in BDNF induced by maternal separation. The highest dose of topiramate was able to reduce IL-10 in the hippocampus and TNF-α in the prefrontal cortex, while valproate only reduced IL-10 levels in the hippocampus. These findings may have implications for a better understanding of the mechanisms associated with alterations observed in adult life induced by early stressful events, and for the proposal of novel therapeutic strategies.

Effects of topiramate on language functions in newly diagnosed pediatric epileptic patients

BACKGROUND

The aim of this study was to characterize the effects of topiramate on language functions in newly diagnosed pediatric epileptic patients.

METHODS

Thirty-eight newly diagnosed epileptic patients were assessed using standard language tests. Data were collected before and after beginning topiramate during which time a monotherapy treatment regimen was maintained. Language tests included the Test of Language Problem Solving Abilities, a Korean version of the Peabody Picture Vocabulary Test. We used language tests in the Korean version because all the patients were spoken Korean exclusively in their families.

RESULTS

All the language parameters of Test of Language Problem Solving Abilities worsened after initiation of topiramate (determine cause, 13.2 ± 4.8 to 11.2 ± 4.3; problem solving, 14.8 ± 6.0 to 12.8 ± 5.0; predicting, 9.8 ± 3.6 to 8.8 ± 4.6). Patients given topiramate exhibited a shortened mean length of utterance in words during response (determine cause, 4.8 ± 0.9 to 4.3 ± 0.7; making inference, 4.5 ± 0.8 to 4.1 ± 1.1; predicting, 5.2 ± 1.0 to 4.7 ± 0.6; P < 0.05), provided ambiguous answers during the testing, exhibited difficulty in selecting appropriate words, took more time to provide answers, and used incorrect grammar. However, there were no statistically significant changes in the receptive language of patients after taking topiramate (95.4 ± 20.4 to 100.8 ± 19.1).

CONCLUSIONS

Our data suggest that topiramate may have negative effects on problem-solving abilities in children. We recommend performing language tests should be considered in children being treated with topiramate.

Acute lorazepam effects on neurocognitive performance

A double-blind, placebo-controlled, crossover design was employed to determine whether acute lorazepam (2 mg orally) cognitive side effects would emerge in a differential age-dependent fashion in 15 young (mean age=22 years) and 12 older (mean age=64 years) subjects. Acute use of lorazepam is frequently the initial treatment choice for convulsive status epilepticus or repetitive seizure clusters. Cognitive assessment was performed during drug and placebo conditions using a computerized battery of cognitive tests. With the exception of performance on the reasoning composite score, significant drug effects were present on all primary cognitive domain measures. However, the only significant drug-by-age interaction effect was seen for dual-task performance. The relationship between test performance and plasma lorazepam concentrations was generally modest and non-significant, suggesting that individual differences in pharmacokinetics are not a major factor contributing to the emergence of cognitive side effects. Despite robust lorazepam effects on multiple measures of neurocognitive function, differential age effects are largely restricted to dual-task performance. These results indicate that with the exception of dual-task performance, older individuals in the age range of this study do not appear to be at increased risk for the emergence of cognitive side effects following a single 2-mg dose of lorazepam.