Monotherapy has been considered the gold standard for drug treatment of epilepsy. However, there is renewed interest in polytherapy because of the advent of new drugs with fewer drug interactions and novel mechanisms of action, and the realization that most patients with refractory epilepsy are eventually treated with drug combinations. Careful consideration must be given to drug additions and conversions; it may be less risky to add a drug than to convert from one monotherapy to another in patients with frequent or severe seizures. Rational choice of drug combinations is, at present, based more on avoidance of pharmacodynamic or pharmacokinetic side effects than on evidence for supra-additive efficacy. There are indications that combinations of two sodium-channel blocking agents are less effective than combinations of drugs with different primary mechanisms of action, and some human studies suggest that lamotrigine and valproate may be synergistic for efficacy. However, more animal and human research is needed, with attention to the effects of various combinations on both toxicity and seizure control.

OBJECTIVE: Intracranial electroencephalography (ICEEG) with chronically implanted electrodes is a costly invasive diagnostic procedure that remains necessary for a large proportion of patients who undergo evaluation for epilepsy surgery. This study was designed to evaluate whether magnetic source imaging (MSI), a noninvasive test based on magnetoencephalography source localization, can supplement ICEEG by affecting electrode placement to improve sampling of the seizure onset zone(s). METHODS: Of 298 consecutive epilepsy surgery candidates (between 2001 and 2006), 160 patients were prospectively enrolled by insufficient localization from seizure monitoring and magnetic resonance imaging results. Before presenting MSI results, decisions were made whether to proceed with ICEEG, and if so, where to place electrodes such that the hypothetical seizure-onset zone would be sampled. MSI results were then provided with allowance of changes to the original plan. RESULTS: MSI indicated additional electrode coverage in 18 of 77 (23%) ICEEG cases. In 39%(95% confidence interval, 16.4-61.4), seizure-onset ICEEG patterns involved the additional electrodes indicated by MSI. Sixty-two patients underwent surgical resection based on ICEEG recording of seizures. Highly localized MSI was significantly associated with seizure-free outcome (mean, 3.4 years; minimum,>1 year) for the entire surgical population (n = 62). INTERPRETATION: MSI spike localization increases the chance that the seizure-onset zone is sampled when patients undergo ICEEG for presurgical epilepsy evaluations. The clinical impact of this effect, improving diagnostic yield of ICEEG, should be considered in surgery candidates who do not have satisfactory indication of epilepsy localization from seizure semiology, electroencephalogram, and magnetic resonance imaging. Ann Neurol 2009;65:716-723.

Topiramate (TPM) is a widely-used drug for the treatment of epilepsy. It is useful for several types of partial-onset and generalized-onset seizures, and is therefore considered a broad-spectrum agent. It is also effective as a prophylactic against migraine headaches. TPM was first approved for prescription use in 1996. In various countries it is now approved for adjunctive and monotherapy of partial-onset seizures and for therapy of generalized tonic-clonic seizures of nonfocal origin, for children and adults. For initial monotherapy of new-onset seizures, a target dose of 100 mg/day for adults is recommended. Adjunctive use with enzyme-inducing drugs and use for refractory seizures requires higher dosages, though the optimum dose for most patients does not exceed 400 mg/day. Excretion is primarily renal and TPM is not a significant hepatic enzyme inducer. Although it is usually safe and well-tolerated, adverse effects limit use in about 25% of patients. The most salient of these is cognitive dysfunction, especially problems with expressive speech and verbal memory. Weight loss, renal stones, paresthesias and other central nervous system side effects may occur. Tolerability is improved by low initial doses and slow titration to effect.

BACKGROUND: Valproic acid (VPA) has been associated with hyperammonemia with and without encephalopathy. We report the frequent but transient nature of hyperammonemia following intravenous (IV) administration of loading doses of VPA. METHODS: Forty participants received a VPA loading dose (20 or 30mg/kg) at 6 or 10mg/kg/min. All participants were monitored for signs of systemic and local intolerance. Serum VPA level, ammonia, complete blood count, bilirubin, transaminases, pancreatic enzymes, and level of consciousness were obtained at baseline, 1 and 24h after administration. Changes in ammonia levels were assessed using repeated-measures ANOVA. RESULTS: Asymptomatic hyperammonemia occurred in 30 of 40 participants at 1h post-VPA infusion. Majority of the participants (66%) demonstrated decreasing ammonia concentrations at 24h post-infusion. Multivariable repeated-measures analysis indicates the lack of influence of VPA dose (p=0.8), VPA levels (p>0.24, all time points), infusion rate (p=0.41) and gender (0.68) on ammonia levels across time. Age (p=0.015), time since dosing (p=0.017) and co-therapy with enzyme-inducing antiepileptic drugs (p=0.035) were significant predictors of changes in ammonia levels. CONCLUSIONS: Hyperammonemia is a frequent but transient finding following intravenous administration of loading doses of VPA. Hyperammonemia was not associated with alteration in consciousness or hepatic transaminases.

OBJECTIVE: To evaluate the efficacy, safety, and tolerability of carisbamate (CRS), an investigational drug, as adjunctive treatment for partial-onset seizures in adults. METHODS: A randomized, double-blind, placebo-controlled, multicenter, dose-ranging study was conducted in 12 countries. Patients counted seizures during an 8-week baseline period, and then, if eligible, entered a double-blind phase consisting of a 4-week dose-titration period (target CRS doses: 100, 300, 800, or 1,600 mg/d or placebo in two divided doses) and a 12-week maintenance period. The primary efficacy variable was percent reduction in partial-onset seizure frequency during the double-blind phase compared with pretreatment baseline. Safety data and responder rates were also assessed. RESULTS: Five hundred thirty-seven patients were randomized, and 82% completed the study. In the intent-to-treat population (n = 533), CRS at doses of >/=300 mg/d (p </= 0.006) reduced the frequency of partial-onset seizures vs placebo: 6%(placebo) vs 24%(300 mg/d), 21%(800 mg/d), and 29%(1,600 mg/d) for CRS. Adverse events consisted primarily of CNS effects, and led to discontinuation of drug in 8% of the placebo group vs 5%(100 mg/d), 6%(300 mg/d), 12%(800 mg/d), and 19%(1,600 mg/d) of the CRS groups. CONCLUSIONS: Carisbamate at doses of 300, 800, and 1,600 mg/d was effective as adjunctive therapy for reducing the frequency of partial-onset seizures. GLOSSARY: AED = antiepileptic drug; ALT = alanine aminotransferase; AST = aspartate aminotransferase; CRS = carisbamate; LFT = liver function test; TEAE = treatment-emergent adverse event; UGT = uridine diphosphate glucuronosyltransferase.

OBJECTIVE: To gain information on the value of magnetic source imaging (MSI), 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), and ictal single photon emission computed tomography (SPECT) to predict seizure-free outcome following epilepsy surgery in patients who require intracranial electroencephalography (ICEEG). METHODS: This work was part of a prospective observation study of epilepsy surgery candidates not sufficiently localized with scalp EEG and MRI. Of 160 patients enrolled 62 completed ICEEG and subsequent surgical resection. Sixty-one percent resulted in an Engel I seizure-free outcome at a minimum of one-year follow-up (mean = 3.4 years). Sensitivity, specificity, and predictive values were computed for each modality. Multivariate logistical regression was used to identify prediction of surgical outcome by imaging test. RESULTS: MSI sensitivity for a conclusively localized study was 55% with a positive predictive value of 78%. Eliminating non-diagnostic MSI cases (no spikes captured during recording) yielded a corrected negative predictive value of 64%. With available comparison subgroups FDG-PET and ictal SPECT values were similar to MSI. The OR (adjusted for epilepsy and MRI classification) for MSI prediction of seizure-free outcome was 4.4 (p =0.01). In cases with both PET and MSI, the adjusted OR for PET was 7.1 (p <0.01) and for MSI was 6.4 (p = 0.01). In the cases with all three tests (n = 27), ictal SPECT had the highest OR of 9.1 (p = 0.05). INTERPRETATION: MSI, FDG-PET, and ictal SPECT each have clinical value in predicting seizure-free surgical outcome in epilepsy surgery candidates who typically require ICEEG. Ann Neurol 2008.

OBJECTIVES: The primary objective was to investigate whether nonadherence to antiepileptic drugs (AEDs) is associated with increased mortality and the secondary objective to examine whether nonadherence increases the risk of serious clinical events, including emergency department (ED) visits, hospitalizations, motor vehicle accident (MVA) injuries, fractures, and head injuries. METHODS: A retrospective open-cohort design was employed using Medicaid claims data from Florida, Iowa, and New Jersey from January 1997 through June 2006. Patients aged >/=18 years with >/=1 diagnosis of epilepsy by a neurologist and >/=2 AED pharmacy dispensings were selected. Medication possession ratio (MPR) was used to evaluate AED adherence on a quarterly basis with MPR >/=0.80 considered adherent and <0.80 nonadherent. The association of nonadherence with mortality was assessed using a time-varying Cox regression model adjusting for demographic and clinical confounders. Incidence rates for serious clinical events were compared between adherent and nonadherent quarters using incidence rate ratios (IRRs) with 95% CIs calculated based on the Poisson distribution. RESULTS: The 33,658 study patients contributed 388,564 AED-treated quarters (26% nonadherent). Nonadherence was associated with an over threefold increased risk of mortality compared to adherence (hazard ratio = 3.32, 95% CI = 3.11-3.54) after multivariate adjustments. Time periods of nonadherence were also associated with a significantly higher incidence of ED visits (IRR = 1.50, 95% CI = 1.49-1.52), hospital admissions (IRR = 1.86, 95% CI = 1.84-1.88), MVA injuries (IRR = 2.08, 95% CI = 1.81-2.39), and fractures (IRR = 1.21, 95% CI = 1.18-1.23) than periods of adherence. CONCLUSION: These findings suggest that nonadherence to antiepileptic drugs can have serious or fatal consequences for patients with epilepsy.

Individuals with epilepsy commonly experience memory loss. We investigated the safety and tolerability of galantamine in treatment of memory loss in a pilot study of 28 patients with epilepsy, randomly assigned to galantamine (n=13) or placebo (n=15) and followed for a total of 12 weeks. Participants underwent blinded memory assessment at baseline and 12 weeks (Selective Reminding Test, 7/24 Spatial Recall). One participant in the galantamine group had a suspected recurrence of brain neoplasm and increased seizures; all other participants receiving galantamine showed no increase in seizure activity during the trial. Patients in both groups reported mild, tolerable side effects (headache, appetite suppression), with no difference between groups. No significant differences were observed on the memory measures when both groups were retested at Week 12. Galantamine appears to be safe and tolerable in patients with epilepsy. Further studies with larger samples and comparison with other cholinesterase inhibitors should be considered.

The purpose of the study was to compare figural and spatial memory in patients with left (LTLE, n=56) and right (RTLE, n=48) temporal lobe epilepsy using J.I. Breier and colleagues'(J Int Neuropsychol Soc 1996;2:535-40) figural/spatial scoring method for the Rey Osterrieth Complex Figure Test (RCFT). The study also examined the association between figural and spatial components of the RCFT, temporal lobe laterality, and hippocampal structure (MRI hippocampal volumes and neuropathology ratings). Neither immediate or delayed trial figural and spatial memory scores were associated with seizure laterality or hippocampal pathology ratings. Immediate and delayed recall scores were not associated with right hippocampal volume. However, modestly positive correlations were found between left hippocampal volume and RCFT delayed recall scores. Similar to recent work (A.C. Kneebone et al., J Int Neuropsychol Soc 2007;13:664-71), stronger associations were related to left temporal lobe function. This study provides further evidence for the lack of sensitivity of the RCFT as a surrogate measure of right temporal lobe memory function.

OBJECTIVE: To gain information on the predictive and prognostic value of magnetic source imaging (MSI), 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (18 FDG-PET), and ictal single-photon emission computed tomography (SPECT) as compared with intracranial electroencephalography (ICEEG) localization in epilepsy surgery. METHODS: This work was part of a cohort study of epilepsy surgery candidates not sufficiently localized with noninvasive studies. Of 160 patients enrolled over 4 years, 77 completed ICEEG seizure monitoring. Sensitivity, specificity, and predictive values relative to ICEEG were computed for each modality. RESULTS: Seizures were not captured in five patients. Of the 72 diagnostic ICEEG studies, seizure localization results were 74% localized, 10% multifocal, and 17% nonlocalized. Sixty-one percent were localized to neocortical regions. Depending on patient subgroup pairs, sensitivity ranged from 58 to 64%(MSI), 22 to 40%(PET), and 39 to 48%(SPECT); specificity ranges were 79 to 88%(MSI), 53 to 63%(PET), and 44 to 50%(SPECT). Gains in diagnostic yield were seen only with the combination of MSI and PET or MSI and ictal SPECT. Localization concordance with ICEEG was greatest with MSI, but a significant difference was demonstrated only between MSI and PET. Moderate redundancy was seen between PET and ictal SPECT (kappa = 0.452; p = 0.011). INTERPRETATION: Conclusively positive MSI has a high predictive value for seizures localized with ICEEG. Diagnostic gain may be achieved with addition of either PET or ictal SPECT to MSI. Diagnostic values for imaging tests are lower than "true values" because of the limitations of ICEEG as a gold standard. Ann Neurol 2008.