Antiepileptic drugs and their impact on balance

Effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy

BACKGROUND

It is reported that antiepileptic drugs have an effect on balance functions. The aim of the study was to evaluate and compare the effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy using objective test methods.

METHODS

The study included 43 generalized epilepsy patients aged 18-60 years, including 20 patients receiving valproic acid monotherapy, 23 patients receiving levetiracetam monotherapy, and 25 healthy individuals as controls, in the Neurology Clinic of a university hospital in eastern Turkey. The demographic data form was filled out and the Video Head Impulse Test and Vestibular Evoked Myogenic Potentials test were performed.

RESULTS

Statistically significant differences were obtained between the groups in lateral, posterior, and anterior semicircular canal gains and RALP and LARP asymmetry values in the V-HIT test (p < 0.05). Statistically significant differences were obtained between the groups in P1, N1 latency and asymmetry values in the C-VEMP test and in N1, P1 latency, amplitude, and asymmetry values in the o-VEMP test (p < 0.05).

CONCLUSION

Valproic acid and levetiracetam may affect the vestibulocular and vestibulocolic reflex pathways negatively. In this cohort, valproic acid had more pronounced adverse effects on balance functions as compared to levetiracetam.

Falls in community-dwelling women with bipolar disorder: a case-control study

BACKGROUND

Falls are a common occurrence in psychiatric hospital settings, however population-based research among individuals with psychiatric disorders, in particular bipolar disorder (BD) is scant. Thus, we aimed to investigate falls risk in community-dwelling women diagnosed with BD.

METHODS

Women with BD (cases, n = 119) were recruited from health care settings located in southeast Victoria, Australia. Age-matched controls (n = 357, ratio 3:1) without BD were participants in the Geelong Osteoporosis Study drawn from the same geographical region. Lifetime history of BD was identified by semi-structured clinical interview (SCID-IV/NP). Previous 12-month falls data were obtained via questionnaire. Information on mobility, alcohol use, general health, medication use, blood pressure, body mass index, socioeconomic status and use of a walking aid was collected. Generalised Estimating Equations, binary and ordinal logistic regression were used to determine the odds ratio (OR) and 95% confidence interval (CI) for falls following adjustment for confounders.

RESULTS

During the 12-month period, 34 (28.6%, median age 48.4 yr) cases and 70 (19.6%, median age 49.1 yr) controls reported one fall; 22 (18.5%) cases and 18 (5.0%) controls reported ≥ two falls (p < 0.001). Cases had 2.5-fold increased odds of at least one fall and 2.9-fold increased likelihood of increasing falls categories (0 vs. 1 vs. 2 +), compared to controls [adjOR 2.5, 95%CI (1.8, 3.4), adjOR OR 2.9, 95%CI (2.0, 4.1)].

CONCLUSION

Risk of falls was greater among women with BD. Balance training could be a research and clinical focus for falls prevention programs among women with bipolar disorder to prevent the detrimental outcomes associated with falling.

An insight into the implications of estrogen deficiency and transforming growth factor β in antiepileptic drugs-induced bone loss

There have been a number of reports that chronic antiepileptic drug (AEDs) therapy is associated with abnormal bone and calcium metabolism, osteoporosis/osteomalacia, and increased risk of fractures. Bony adverse effects of long term antiepileptic drug therapy have been reported for more than four decades but the exact molecular mechanism is still lacking. Several mechanisms have been proposed regarding AEDs induced bone loss; Hypovitaminosis D, hyperparathyroidism, estrogen deficiency, calcitonin deficiency. Transforming growth factor-β (TGF- β) is abundant in bone matrix and has been shown to regulate the activity of osteoblasts and osteoclasts in vitro. All isoforms of TGF- β are expressed in bone and intricately play role in bone homeostasis by modulating estrogen level. Ovariectomised animal have shown down regulation of TGF- β in bone that could also be a probable target of AEDs therapy associated bone loss. One of the widely accepted hypotheses regarding the conventional drugs induced bone loss is hypovitaminosis D which is by virtue of their microsomal enzyme inducing effect. However, despite of the lack of enzyme inducing effect of certain newer antiepileptic drugs, reduced bone mineral density with these drugs have also been reported. Thus an understanding of bone biology, pathophysiology of AEDs induced bone loss at molecular level can aid in the better management of bone loss in patients on chronic AEDs therapy. This review focuses mainly on certain new molecular targets of AEDs induced bone loss.

Incidence of clinical fractures: A 7-year follow-up study in institutionalized adults with epilepsy and intellectual disability

PURPOSE

To determine the incidence of clinical fractures over seven years of follow-up, in adults with epilepsy and intellectual disability, residing in a long-stay care facility.

METHODS

In 2009, all institutionalized adult patients (n = 261) were invited to undergo a Dual-energy X-ray Absorptiometry (DXA) measurement and a Vertebral Fracture Assessment (VFA). Participants were followed over seven years or until date of discharge (in case of moving from the care facility) or date of death. The patients' medical files were screened for radiology reports and staff notes, to identify clinical fractures. Fracture incidence rates (IR) were determined and compared for subgroups, by calculating incidence rate ratios. Hazard ratios were calculated to identify factors associated with fracture risk, using Cox Proportional Hazards analyses.

RESULTS

A total of 205 patients (124 male, 60.5%) aged between 18 and 88 years (median 48, IQR 34-60) were enrolled. At baseline, 92 patients (44.9%) were diagnosed with osteopenia and 65 (31.7%) with osteoporosis. Between 2009 and 2016, 30 patients (14.6%) deceased and 3 patients (1.5%) left the care facility. During follow-up, 156 clinical fractures were reported in 82 patients (40.0%). Thirty-eight patients (18.5%) had at least one major osteoporotic fracture. Overall, the IR was 11.6 fractures per 100 person-years. Fracture risk was significantly lower in patients who were wheelchair dependent than in patients who were able to walk (p<.001).

CONCLUSION

This study demonstrated that 40% of institutionalized adults with epilepsy and intellectual disability had at least one clinical fracture during seven years of follow-up, despite adequate anti-osteoporosis treatment.

Cognitive and sensorimotor function in participants being treated for trigeminal neuralgia pain

BACKGROUND

Trigeminal neuralgia (TN) is an orofacial condition defined by reoccurring, spontaneous, short-lived but excruciating stabbing pain. Pharmacological interventions constitute the first-line treatment for TN, with antiepileptic drugs commonly prescribed. People treated for TN pain with antiepileptic drugs describe cognitive and motor difficulties affecting activities of daily living, and report poorer quality of life. We undertook the first comprehensive objective evaluation of sensorimotor and cognitive performance in participants being treated for TN pain with antiepileptic drugs relative to age-matched controls.

METHODS

Participants (43 TN, 41 control) completed a battery of sensorimotor (steering, aiming and tracking) and cognitive (working memory, processing speed, inhibition) tasks.

RESULTS

The TN group performed significantly worse than controls on the sensorimotor tracking and aiming tasks and across all cognitive measures.

CONCLUSIONS

The data explain why patients treated with antiepileptic drugs report impairment when conducting activities of daily living (given the need for cognitive and motor capability within most of these). The study is an important first step in: (i) ensuring there is adequate information on the impact of pharmacological treatment; (ii) identifying measures to determine optimal medication dosage and track change over time; (iii) creating an evidence base that could allow scientific justification of alternative pain treatment options for TN (e.g. the costs/benefits of surgery).

The utility of the Sports Concussion Assessment Tool in hospitalized traumatic brain injury patients

The Sports Concussion Assessment Tool 3rd version is a sports screening tool that is often used to support return to play decisions following a head injury. The Sports Concussion Assessment Tool 3rd version is presumed to identify brain dysfunction (implying a degree of brain injury); however, the Sports Concussion Assessment Tool has never been validated with patients with definite acute brain injury. In this study, we found that all three Sports Concussion Assessment Tool 3rd version domains – symptoms, cognitive and balance assessments – were sensitive in discriminating traumatic brain injury patients (all with abnormal acute neuroimaging) from healthy controls. Through a correlation matrix (Bonferroni corrected), we found no correlation between the subjective (symptoms) and objective (examination) Sports Concussion Assessment Tool 3rd version assessments, e.g. complaints of imbalance and memory dysfunction were not correlated, respectively, with performance on testing balance and memory function. When relaxing the correction for multiple comparisons we found that of all Sports Concussion Assessment Tool 3rd version symptoms, a feeling of ‘pressure in the head’ had the largest number of co-correlations (including affective symptoms) and overwhelmingly in a pattern indicative of migraine. Taken together, that objective and subjective assessments in the Sports Concussion Assessment Tool 3rd version are poorly correlated, could suggest that symptoms in the Sports Concussion Assessment Tool 3rd version poorly reflect brain injury but rather indicate non-brain injury processes such as migraine. It follows that the current prominent orthodoxy of resting athletes following a head injury until their symptoms settle for fear of exacerbating brain injury may be unfavourable for their recovery – at least in some cases. Prospective clinical studies would be required to assess patient recovery from concussion with early active investigation and treatment versus rest – a notion supported by recent international consensus.

Bone Health and Endocrine Comorbidities in Pediatric Epilepsy

Antiseizure medications and dietary therapies have associated effects on the endocrine system. We provided an overview of the relationship between epilepsy treatment and bone health in children with epilepsy. Additionally, we discussed the effects of epilepsy treatment on other endocrine systems including thyroid function, growth, reproduction, and weight. The effect of epilepsy on bone health is multifactorial; there are direct and indirect effects of medication and dietary treatments as well as a decrease in physical activity, decreased sunlight exposure, decreased vitamin D levels, and additional comorbidities. Some medications have a greater effect on vitamin D and bone health than others, however all antiseizure medical treatments are associated with lower vitamin D levels in pediatric patients. We have provided practical suggestions for vitamin D surveillance in children with epilepsy as well as replacement strategies. Children with epilepsy have an increased likelihood of additional endocrine disorders including subclinical hypothyroidism, decreased growth, weight abnormalities, reproductive and sexual dysfunction. To a great extent, this is medication specific. Though more studies are needed to elucidate optimal treatment and monitoring of bone health and other endocrinopathies in children with epilepsy, it is critical that caregivers pay close attention to these issues to provide optimal comprehensive care to their patients.

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.

Comparing the effects of first-line antiepileptic drugs on the gait of dogs with idiopathic epilepsy

Idiopathic epilepsy (IE) is a common chronic neurological disease of the dog. Previous studies of anti-epileptic drug (AED) treatment have indicated that acceptable AED adverse effects are as important to owners as reductions in seizure frequency. AEDs in both dogs and human beings are frequently associated with the adverse-effect ataxia. The aim of this study was to compare ataxia levels in dogs with IE treated chronically with phenobarbitone or imepitoin, the two currently available first-line AED treatments. The gait of 6 imepitoin-treated dogs, 8 phenobarbitone-treated dogs and 10 age-matched healthy control dogs were compared. Fifty strides from a walking gait were analysed for each dog, quantifying ataxia via the variability in six established gait parameters. Three variables differed significantly between groups: lateral distance between (i) pelvic paw placements, (ii) thoracic paw placements and (iii) stance time, which were significantly more variable in the phenobarbitone-treated dogs than imepitoin-treated or control dogs. These results indicate that dogs treated with phenobarbitone experience ataxia compared with controls and imepitoin-treated dogs. Conversely, there was no difference between imepitoin-treated dogs and controls. These results along with further research are needed to quantify AEDs adverse effects, to help vets and owners make more informed drug-choices.

Adverse effects of valproate on bone: defining a model to investigate the pathophysiology

PURPOSE

Bone disease and fractures are common with chronic antiepileptic drug (AED) therapy, but the underlying mechanisms are poorly understood. This study aimed to characterize adverse bone effects of valproate and to identify mouse strains either resistant or sensitive to these effects.

METHODS

Seven mouse strains (n = 40/strain; 10/diet) were screened for the effect of chronic (8 weeks) valproate treatment (0, 2, 4, and 6 g/kg food) on total bone mineral content (BMC, by dual energy x-ray absorptiometry). In a confirmatory study the effect of valproate (0 or 4 g/kg food) over 16 weeks was assessed in five of the mouse strains (n = 60/strain; 30/diet) identified in the screening phase as either sensitive or resistant. Ex vivo volumetric bone measures and structural changes were assessed using peripheral quantitative computed tomography (pQCT) and histomorphometry.

RESULTS

Chronic valproate treatment reproducibly affected bone in C3H/HeJ mice, with a 9.1% (p < 0.01) reduction in total BMC and a 10.7% (p < 0.01) reduction in trabecular volumetric density, indicating a sensitive strain to AED-induced bone loss. Histomorphometry was consistent, revealing reductions in trabecular volume (19.6%, p < 0.05) and number (14.3%, p < 0.04), and a 19.9% (p < 0.05) increase in trabecular separation. In contrast the A/J mice were reproducibly resistant to the bone effects.

CONCLUSION

Mouse strains sensitive and resistant to the adverse bone effects of chronic valproate treatment were identified. The strain-specific effects suggest a role of genetic factors in the pathogenesis of AED-induced bone disease. This novel model provides a new, powerful tool to investigate the pathophysiology and therapy of AED-associated bone disease.

Second-generation antiepileptic drugs' impact on balance: a meta-analysis

OBJECTIVE

To systematically review available evidence regarding whether second-generation antiepileptic drugs (AEDs) contribute to the risk of balance disorders.

METHODS

We systematically evaluated data from randomized controlled trials that compared adjunctive therapy with a second-generation AED (gabapentin, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, tiagabine, topIramate, or zonisamide) vs placebo for partial epilepsy and that reported dose-specific rates of ataxia or Imbalance for each group. Random-effects meta-analysis was used to pool ratios (risk ratio [RR]) and associated 95% confidence Intervals to determine whether there was evidence of an overall AED class effect or a dose-response effect and whether there were differences between Individual AEDs.

RESULTS

Sixteen studies met inclusion criteria, representing 4279 individuals randomized to a second-generation AED and 1830 patients to placebo. Pooled analyses of all AEDs demonstrated that they Increase imbalance risk at any dose (RR, 2.73; 95% confidence interval, 2.07-3.61) and at lowest dose (RR, 1.76; 95% confidence interval, 1.26-2.46). The highest dose analysis showed heterogeneity; evaluation of individual AEDs revealed that oxcarbamazepine and topiramate increased imbalance risk at all doses, whereas gabapentin and levetiracetam did not increase imbalance risk at any dose. A dose-response effect was observed for most AEDs.

CONCLUSION

Second-generation AEDs at standard dosages, except for gabapentin and levetiracetam, increase the imbalance risk, and evidence exists for a dose-response effect. The mechanisms, risk factors, and consequences of this risk for individual AEDs warrant further study.

Measuring the effects of antiepileptic medications on balance in older people

BACKGROUND

Dizziness and ataxia are among the most common adverse events associated with antiepileptic medications. Despite this, few studies have attempted to quantitatively assess the effects of antiepileptic therapies on equilibrium. This study was undertaken to prospectively compare quantitative measures of balance in older people taking carbamazepine, gabapentin and lamotrigine.

METHODS

Thirty patients on monotherapy for idiopathic partial or generalized epilepsy were enrolled after giving informed consent. Patients had to be at least 50 years old, able to give consent, and on a stable dose of carbamazepine, gabapentin or lamotrigine for at least 30 days. Since this was a study of asymptomatic patients, all patients had to be without complaint of dizziness or imbalance. Patients with a history of alcohol or drug abuse or any medical or neurological condition expected to adversely affect equilibrium were excluded. Each patient underwent a history and examination, computerized dynamic posturography, the activities-specific balance confidence (ABC) scale, Fregly ataxia battery, and the Berg balance scale. Serum drug levels of carbamazepine were obtained to eliminate patients with toxic levels upon enrollment. Two-tailed paired t-tests were used to determined statistical significance among those on each antiepileptic medication.

RESULTS

Thirty patients were enrolled: 10 on gabapentin, 10 on lamotrigine and 10 on carbamazepine monotherapy for epilepsy. There were no differences in age or sex among those in each treatment group. The average dosages were 1,120 mg/day for those on gabapentin, 335 mg for lamotrigine, and 640 mg for carbamazepine. There were no differences in the activities-specific balance confidence (ABC) or the Berg balance scale scores. All patients had normal vestibular function by quantitative testing. Posturography showed no statistically significant differences. The Fregly ataxia battery includes the sum of timed trials in the sharpened Romberg (SR) position, standing on one leg with eyes closed (SOLEC), and when walking in tandem with eyes closed (WITEC). The patients on lamotrigine exhibited ability to maintain balance in these positions significantly longer than did those on carbamazepine: SR (P<0.05), SOLEC (P<0.05) and WITEC (P<0.05).

CONCLUSIONS

The effects of antiepileptic medications on equilibrium in asymptomatic older people may require more dynamic and challenging measures of equilibrium than are commonly employed in physical therapy to monitor risk of falls. Although the sample size is small, this study suggests that lamotrigine may induce less disequilibrium than does carbamazepine in older people on monotherapy for epilepsy. Further study in this area is needed, particularly given the risks of falling from imbalance in the elderly.