Steve Chung

Electrical stimulation of the anterior nucleus of thalamus for treatment of refractory epilepsy.

Purpose:  We report a multicenter, double‐blind, randomized trial of bilateral stimulation of the anterior nuclei of the thalamus for localization‐related epilepsy.

Lacosamide as adjunctive therapy for partial‐onset seizures: A randomized controlled trial

Purpose:  To evaluate the efficacy and safety of lacosamide (400 and 600 mg/day) as adjunctive treatment in patients with uncontrolled partial‐onset seizures taking one to three concomitant antiepileptic drugs (AEDs).

New-onset seizures in adults: Possible association with consumption of popular energy drinks

Energy drinks contain a mixture of compounds, of which caffeine, guarana, and herbal supplements such as ginkgo and ginseng are major components. Survey of popular literature reveals anecdotal observations of adverse events associated with consumption of energy drinks. However, there are no reported cases in the published literature. We report a series of four patients who had discrete seizures on multiple occasions, following heavy consumption of energy drinks. Once the patients were abstinent from the energy drinks, no recurrent seizures were reported. We propose that the large consumption of energy drinks rich in caffeine, taurine, and guarana seed extract could have provoked these seizures.

Comparative retention rates and long-term tolerability of new antiepileptic drugs

OBJECTIVE Retention rates of five new anti-epileptic medications (AEDs) were compared in order to evaluate their long-term tolerability and efficacy. METHOD We acquired the retention data on levetiracetam (LEV), lamotrigine (LTG), oxcarbazepine (OXC), topiramate (TPM), and zonisamide (ZNS) from the electronic database. The data included patients age, gender, seizure type, current and previous medications, dosage, main reasons for discontinuation, and duration of therapy. The retention rates of these AEDs were evaluated at 4, 12, 24, 52, and 104 weeks. RESULTS A total of 828 new AED exposures were obtained (LEV=196, LTG=251, OXC=97, TPM=156, ZNS=128) from patients with partial or generalized epilepsy. At 2 years, retention rate was highest with LTG (74.1%), followed by ZNS (60.2%), OXC (58.8%), LEV (53.6%), and TPM (44.2%). When these AEDs were discontinued, it was mainly due to inefficacy (29.5%) and sedating side-effects (20.5%), and commonly within 6 months into therapy. Several important AED specific side-effects leading to discontinuation were identified, including behavioral or irritability from LEV, rash from LTG and OXC, nausea from OXC and ZNS, hyponatremia from OXC, and kidney stones from TPM and ZNS. CONCLUSION Comparing retention rates of new AEDs can provide useful insight into their tolerability and efficacy. This study showed highest retention rate with LTG, which was significantly different from ZNS (p=0.0025), LEV (p<0.0001), OXC (p=0.0024), and TPM (p<0.0001). Beside ineffectiveness, other leading causes of discontinuation were adverse behavioral effects with LEV, rash with LTG and OXC, and sedation for TPM and ZNS.

Cognitive effects of lamotrigine compared with topiramate in patients with epilepsy

Objective: To compare the cognitive effects of lamotrigine vs topiramate as adjunctive therapy in adults with epilepsy. Methods: A multicenter, double-blind, randomized, prospective study was conducted in adults with partial seizures. Lamotrigine or topiramate was introduced as an adjunctive therapy to carbamazepine or phenytoin and titrated over 8 weeks to target doses. These drugs were maintained another 8 weeks (maintenance phase) without dosage changes. The primary endpoint was change from screening to the end of the maintenance phase in a combined analysis of standardized measures of cognition (Controlled Oral Word Association Task [COWA]; Stroop Color–Word Interference; Digit Cancellation; Lafayette Grooved Pegboard, dominant hand; Rey Auditory Verbal Learning Test, delayed recall; and Symbol–Digit Modalities test). Results: For the primary endpoint, cognitive performance at the end of the maintenance phase was better with lamotrigine than with topiramate (415.3 vs 315.1; p < 0.001). On the individual cognitive tests, performance was better with lamotrigine than with topiramate in mean changes from screening on the COWA (p < 0.001), Stroop Color–Word Interference (p = 0.038), and Symbol–Digit Modalities tests (p < 0.001). The treatment effect exceeded the minimum clinically important difference for the COWA and the Symbol–Digit Modalities test. Mean changes from screening in the Performance-On-Line test simulating driving skills reflected better performance with lamotrigine than with topiramate (p = 0.021). The median percentage change from baseline in seizure frequency was lower with lamotrigine than with topiramate during the escalation phase (−80% vs −100%; p = 0.028) but not during the maintenance phase (−75% vs −100%; p = 0.062). The frequencies of cognitive adverse events and of premature withdrawals related to cognitive decline were higher with topiramate than with lamotrigine (6% vs 0%; p = 0.013). Conclusion: Lamotrigine had significantly less impact than topiramate on measures of cognition when used as adjunctive therapy for partial seizures.

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus (NCSE) is a heterogeneous disorder with multiple subtypes. Although attempts have been made to define and classify this disorder, there is yet no universally accepted definition or classification that encompasses all subtypes or electroclinical scenarios. Developing such a classification scheme is becoming increasingly important, because NCSE is more common than previously thought, with a bimodal peak, in children and the elderly. Recent studies have also shown a high incidence of NCSE in the critically ill. Although strong epidemiological data are lacking, NCSE constitutes about 25-50% of all cases of status epilepticus. For the purposes of this review, we propose an etiological classification for NCSE including NCSE in metabolic disorders, NCSE in coma, NCSE in acute cerebral lesions, and NCSE in those with preexisting epilepsy with or without epileptic encephalopathy. NCSE is still underrecognized, yet potentially fatal if untreated. Diagnosis can be established using an electroencephalogram (EEG) in most cases, sometimes requiring continuous monitoring. However, in comatose patients, diagnosis can be difficult, and the EEG can show a variety of rhythmic or periodic patterns, some of which are of unclear significance. Although some subtypes of NCSE are easily treatable, such as absence status epilepticus, others do not respond well to treatment, and debate exists over how aggressively clinicians should treat NCSE. In particular, the appropriate treatment of NCSE in patients who are critically ill and/or comatose is not well established, and large-scale trials are needed. Overall, further work is needed to better define NCSE, to determine which EEG patterns represent NCSE, and to establish treatment paradigms for different subtypes of NCSE.

Endoscopic resection of hypothalamic hamartomas for refractory symptomatic epilepsy.

Background: Hypothalamic hamartomas (HHs), rare developmental abnormalities of the inferior hypothalamus, often cause refractory, symptomatic, mixed epilepsy, including gelastic seizures. We present 37 patients with HH who underwent transcortical transventricular endoscopic resection. Methods: Between October 2003 and April 2005, 42 consecutive patients with refractory epilepsy who underwent endoscopic resection of HH were studied prospectively. The endoscope was held by an articulated pneumatic arm and tracked with a frameless stereotactic neuronavigation system. Data collection and follow-up were performed by personal interview. Five patients were excluded. The remaining 37 patients (22 males, 15 females; median age 11.8 years; range 8 months to 55 years) had frequent and usually multiple types of seizures. Results: Postoperative MRI confirmed 100% resection of the HH from the hypothalamus in 12 patients. At last follow-up (median 21 months; range 13–28 months), 18 (48.6%) patients were seizure free. Seizures were reduced more than 90% in 26 patients (70.3%) and by 50% to 90% in 8 patients (21.6%). Overall, the mean postoperative stay was shorter in the endoscopic patients compared with our previously reported patients who underwent transcallosal resection (mean 4.1 days vs 7.7 days, respectively; p = 0.0006). The main complications were permanent short-term memory loss in 3 patients and small thalamic infarcts in 11 patients (asymptomatic in 9). Conclusions: Endoscopic resection of hypothalamic hamartoma (HH) is a safe and effective treatment for seizures. Its efficacy seems to be comparable to that of transcallosal resection of HH, but postoperative recovery time is significantly shorter.

Interobserver agreement in the interpretation of EEG patterns in critically ill adults.

Summary: The significance of rhythmic and periodic EEG patterns in critically ill patients is unclear. A universal terminology is needed to facilitate study of these patterns, and consistent observer agreement should be demonstrated in its use. The authors evaluated inter- and intraobserver agreement using the standardized terminology (Hirsch et al., J Clin Neurophysiol 2005;22:128–135) recently proposed by the American Clinical Neurophysiology Society. Trained electroencephalographers viewed a series of 10-second EEG samples from critically ill adults (phase I), a set of ≥20-minute EEGs from the same patient cohort (phase II), and then reevaluated the first sample set (phase III). The readers used the proposed terminology to “score” each EEG. For each possible term, interobserver agreement (phases I and II) and intraobserver agreement (phase III) were calculated using pairwise kappa (&kgr;) values. Moderate agreement beyond chance was seen for the presence/absence of rhythmic or periodic patterns and for localization of these patterns. Agreement for other terms was slight to fair. Inter- and intraobserver agreement were consistently lower for optional terms than mandatory terms. Even when standardized terminology is used, the description of rhythmic and periodic EEG patterns varies significantly. Further refinement of the proposed terminology is required to improve inter- and intraobserver agreement.

Examining the Clinical Utility of Lacosamide Pooled Analyses of Three Phase II/III Clinical Trials

AbstractBackground: Lacosamide is an antiepileptic drug (AED) approved for the adjunctive treatment of partial-onset seizures in adults. Completed phase II/III clinical trials of lacosamide provide a valuable opportunity to evaluate clinically relevant aspects of the resulting large patient pool. Objective: To provide insight into the clinical utility of lacosamide by performing a priori-defined and post hoc analyses on a large, pooled patient population. Study Design: Pooled data from three randomized, double-blind, multicentre, placebo-controlled phase II/III trials. Patients: Adult patients with partial-onset seizures with or without secondary generalization (N = 1294). Intervention: Four- to six-week titration followed by 12-week maintenance treatment with lacosamide (Vimpat®) 200, 400 or 600mg/day or placebo. Main Outcome Measure:A priori- defined primary efficacy variables for the pooled analysis were change in seizure frequency per 28 days and the proportion of patients experiencing a ≥50% reduction in seizure frequency (50% responder rate) from Baseline to the Maintenance Phase; a priori-defined secondary efficacy variables were the proportion of patients achieving a ≥75% reduction in seizure frequency from Baseline to the Maintenance Phase (75% responder rate), the proportion of Maintenance Phase completers remaining seizure free throughout the entire Maintenance Phase and the percentage of seizure-free days during the Maintenance Phase for patients entering the Maintenance Phase. The pooled analyses of the change in seizure frequency, and 50% and 75% responder rates were performed with an intent-to-treat (ITT) approach, including all patients receiving at least one dose of trial medication and having at least one post-baseline efficacy assessment. Similar analyses of the two primary efficacy variables and 75% responder rates were also performed using a modified ITT population (ITTm) that included ITT patients who entered the Maintenance Phase. Additional post hoc efficacy analyses were an evaluation of onset of efficacy and assessment of efficacy in patients grouped by prior surgical history and individual concomitant AED use. In addition, pharmacokinetic-pharmacodynamic modelling was performed, and safety data were assessed. Results: In this pooled analysis of 1294 difficult-to-treat patients, all three dosages of lacosamide (200, 400 and 600 mg/day) showed a significant improvement compared with placebo for median percent seizure reduction (ITT and ITTm; p < 0.05 for 200 mg/day, p < 0.001 for 400 and 600 mg/day), as well as for 50% responder rate (ITT and ITTm; p <0.05 for 200 mg/day, p<0.001 for 400 and 600 mg/day). Evaluation of 75% responder rate in the phase II/III pooled population showed that a significantly higher proportion of patients randomized to lacosamide 400 or 600 mg/day achieved a ≥75% reduction in seizure frequency compared with placebo (ITT and ITTm; p < 0.001); statistical significance was not observed for lacosamide 200 mg/day (ITT and ITTm). A total of 2.7%, 3.3% and 4.8% of patients completing the Maintenance Phase in the lacosamide 200, 400 and 600 mg/day groups, respectively, experienced no seizures throughout the entire Maintenance Phase (placebo group = 0.9%). The mean change from baseline in the percentage of seizure-free days in patients entering the Maintenance Phase for the phase II/III pool was 8.0%, 11.6% and 14.7% with lacosamide 200 (p =0.077), 400 (p<0.001) and 600 (p<0.001) mg/day groups, respectively, compared with 6.1% in the placebo group.The onset of efficacy relative to placebo was evident by the first week of treatment with lacosamide. Efficacy was similar in lacosamide-treated patients reporting prior surgical intervention for epilepsy compared to lacosamidetreated patients with no prior surgical intervention. Lacosamide showed a reduction in seizures, regardless of the concomitant AEDs used. The preferred pharmacokinetic-pharmacodynamic model (Emax) supported the therapeutic dose range of lacosamide, and no additional safety concerns were identified in the phase II/III pooled analysis. Conclusions: Results of these a priori-defined and post hoc pooled data analyses from phase II/III trials demonstrate that lacosamide effectively reduces seizures in patients at all three dosages evaluated with an early onset of efficacy, regardless of patient surgical history and concomitant AED regimen.

Long‐term safety and efficacy in patients with uncontrolled partial‐onset seizures treated with adjunctive lacosamide: Results from a phase III open‐label extension trial

Purpose:  To evaluate the long‐term (up to 5 years exposure) safety and efficacy of lacosamide as adjunctive therapy in patients with uncontrolled partial‐onset seizures taking one to three concomitant antiepileptic drugs (AEDs) in open‐label extension trial SP756 (NCT00522275).