Faculty Bibliography

Blurring of the cortical gray and white matter border on MRI is associated with normal aging, pathological aging, and the presence of focal cortical dysplasia. However, it remains unclear whether normal variations in signal intensity contrast at the gray and white matter junction reflect the functional integrity of subjacent tissue. This study explores the relationship between verbal abilities and gray and white matter contrast (GWC) in healthy human adults. Participants were scanned at 3 T MRI and administered standardized measures of verbal expression and verbal working memory. GWC was estimated by calculating the non-normalized T1 image intensity contrast above and below the cortical gray/white matter interface. Spherical averaging and whole-brain correlational analyses were performed. Sulcal regions exhibited higher contrast compared to gyral regions. We found a strongly lateralized and regionally specific profile with reduced verbal expression abilities associated with blurring in left hemisphere inferior frontal cortex and temporal pole. Reduced verbal working memory was associated with blurring in widespread left frontal and temporal cortices. Such lateralized and focal results provide support for GWC as a measure of regional functional integrity and highlight its potential role in probing the neuroanatomical substrates of cognition in healthy and diseased populations

Experimental and clinical findings have shown in the past decade that specific proinflammatory mediators and their cognate receptors are upregulated in epileptic brain tissue. In particular, the IL-1 receptor (R)/Toll-like receptor (TLR) signaling pathways are activated in experimental models of seizures and in human epileptic tissue from drug-resistant patients. Pharmacological targeting of these proinflammatory pathways using selective receptor antagonists, or the use of transgenic mice with perturbed cell signaling, demostrated that the activation of IL-1R type 1 and TLR4 by their respective endogenous ligands, i.e., interleukin (IL)-1b and High Mobility Group Box 1, is implicated in the precipitation and recurrence of experimentally induced seizures in rodents. This evidence highlights a new target system for pharmacological intervention to inhibit seizures by interfering with mechanisms involved in their genesis and recurrence.

Using data from NIH Research Portfolio Online Reporting Tools (RePORT) and recently assembled prevalence estimates of 6 major neurologic diseases, we compared the relative prevalences and the annual NIH support levels for 6 major neurologic disorders: Alzheimer disease, amyotrophic lateral sclerosis (ALS), epilepsy, multiple sclerosis, Parkinson disease, and stroke. Compared to these other major neurologic disorders, epilepsy research is funded at a persistently lower rate based on relative disease prevalences. Relative NIH funding for these other disorders in 2010 adjusted for prevalence ranged from 1.7x (stroke) to 61.1x (ALS) greater than epilepsy. The disparity cannot be explained by differences in the overall impact of these diseases on US citizens. Greater transparency in the review and funding process is needed to disclose the reason for this disparity

Over the last two decades a total of 11 antiepileptic drugs (AEDs) have been introduced to the US market. Randomized, placebo-controlled trials have yielded information about each drug's efficacy, tolerability, and safety profile; however, few studies have compared the newer generation AEDs directly with the older generation. Comparative studies are not always straightforward in their interpretation, as many characteristics of drugs, both favorable and unfavorable, may not be highlighted by such studies. In general, findings from the literature suggest that the newer generation AEDs (including vigabatrin, felbamate, gabapentin, lamotrigine, tiagabine, topiramate, levetiracetam, oxcarbazepine, zonisamide, pregabalin, rufinamide, and lacosamide) enjoy both improved tolerability and safety compared with older agents such as phenobarbital, phenytoin, carbamazepine, and valproate. This is partially supported by some of the findings of the QSS and the TTA Committee of the American Academy of Neurology (AAN), whose review of four AEDs (gabapentin, lamotrigine, topiramate, and tiagabine) is discussed. Briefly, when compared with carbamazepine, lamotrigine was better tolerated; topiramate adverse events (AEs) were fairly comparable to carbamazepine and valproate; and tiagabine compared with placebo was associated with a higher discontinuation rate due to AEs. The findings of the SANAD trial are also presented; when administered to patients with partial epilepsy, carbamazepine was most likely to fail due to AEs, and lamotrigine and gabapentin were least likely to fail due to AEs. When administered to patients with idiopathic generalized epilepsy, topiramate was most frequently associated with AE-related discontinuation, followed by valproate; and while valproate was the most efficacious drug in this arm of the study, lamotrigine was more tolerable. What makes the SANAD study valuable and somewhat unique is its head-to-head comparison of one drug with another. Such comparative trials are overall lacking for new AEDs, although some conclusions can be drawn from the available data. In the end, however, AED selection must be based on individual patient and drug characteristics.

The Common Data Element (CDE) Project was initiated in 2006 by the National Institute of Neurological Disorders and Stroke (NINDS) to develop standards for performing funded neuroscience-related clinical research. CDEs are intended to standardize aspects of data collection; decrease study start-up time; and provide more complete, comprehensive, and equivalent data across studies within a particular disease area. Therefore, CDEs will simplify data sharing and data aggregation across NINDS-funded clinical research, and where appropriate, facilitate the development of evidenced-based guidelines and recommendations. Epilepsy-specific CDEs were established in nine content areas: (1) Antiepileptic Drugs (AEDs) and Other Antiepileptic Therapies (AETs), (2) Comorbidities, (3) Electrophysiology, (4) Imaging, (5) Neurological Exam, (6) Neuropsychology, (7) Quality of Life, (8) Seizures and Syndromes, and (9) Surgery and Pathology. CDEs were developed as a dynamic resource that will accommodate recommendations based on investigator use, new technologies, and research findings documenting emerging critical disease characteristics. The epilepsy-specific CDE initiative can be viewed as part of the larger international movement toward 'harmonization' of clinical disease characterization and outcome assessment designed to promote communication and research efforts in epilepsy. It will also provide valuable guidance for CDE improvement during further development, refinement, and implementation. This article describes the NINDS CDE Initiative, the process used in developing Epilepsy CDEs, and the benefits of CDEs for the clinical investigator and NINDS

BACKGROUND: To evaluate the efficacy of highly-active antiretroviral therapy (HAART) in individuals taking cytochrome P450 enzyme-inducing antiepileptics (EI-EADs), we evaluated the virologic response to HAART with or without concurrent antiepileptic use. METHODS: Participants in the US Military HIV Natural History Study were included if taking HAART for >/=6 months with concurrent use of EI-AEDs phenytoin, carbamazepine, or phenobarbital for >/=28 days. Virologic outcomes were compared to HAART-treated participants taking AEDs that are not CYP450 enzyme-inducing (NEI-AED group) as well as to a matched group of individuals not taking AEDs (non-AED group). For participants with multiple HAART regimens with AED overlap, the first 3 overlaps were studied. RESULTS: EI-AED participants (n = 19) had greater virologic failure (62.5%) compared to NEI-AED participants (n = 85; 26.7%) for the first HAART/AED overlap period (OR 4.58 [1.47-14.25]; P = 0.009). Analysis of multiple overlap periods yielded consistent results (OR 4.29 [1.51-12.21]; P = 0.006). Virologic failure was also greater in the EI-AED versus NEI-AED group with multiple HAART/AED overlaps when adjusted for both year of and viral load at HAART initiation (OR 4.19 [1.54-11.44]; P = 0.005). Compared to the non-AED group (n = 190), EI-AED participants had greater virologic failure (62.5% vs. 42.5%; P = 0.134), however this result was only significant when adjusted for viral load at HAART initiation (OR 4.30 [1.02-18.07]; P = 0.046). CONCLUSIONS: Consistent with data from pharmacokinetic studies demonstrating that EI-AED use may result in subtherapeutic levels of HAART, EI-AED use is associated with greater risk of virologic failure compared to NEI-AEDs when co-administered with HAART. Concurrent use of EI-AEDs and HAART should be avoided when possible

OBJECTIVE: To evaluate the efficacy and safety of ezogabine (United States adopted name)/retigabine (international nonproprietary name) (EZG[RTG]) 1,200 mg/day as adjunctive treatment in adults with drug-resistant epilepsy with partial-onset seizures with or without secondary generalization. METHODS: RESTORE 1 was a multicenter, randomized, double-blind, parallel-group trial. Following a prospective 8-week baseline phase, patients entered an 18-week double-blind treatment period (6-week forced dose titration to EZG[RTG] 1,200 mg/day in 3 equally divided doses or placebo, followed by a 12-week maintenance phase). Results were analyzed on an intent-to-treat basis for the entire 18-week period and for patients reaching the maintenance phase. RESULTS: In 306 patients randomized, 305 received EZG(RTG) 1,200 mg/day (n = 153) or placebo (n = 152). Median percent reduction in total partial-seizure frequency was 44.3% vs 17.5% (p < 0.001) for EZG(RTG) and placebo, respectively, during the 18-week double-blind period; responder rates (>/=50% reduction in total partial-seizure frequency from baseline) were 44.4% vs 17.8% (p < 0.001). In 256 patients (EZG[RTG], 119; placebo, 137) entering the 12-week maintenance phase, median percent reduction in seizure frequency for EZG(RTG) vs placebo was 54.5% and 18.9% (p < 0.001), respectively; responder rates were 55.5% vs 22.6% (p < 0.001). The proportion of patients discontinuing due to treatment-emergent adverse events (TEAEs) was 26.8% (EZG[RTG]) vs 8.6% (placebo). Dizziness, somnolence, fatigue, confusion, dysarthria, urinary tract infection, ataxia, and blurred vision were the most common TEAEs reported by more patients treated with EZG(RTG) than placebo. CONCLUSIONS: This study demonstrates that EZG(RTG) is effective as add-on therapy for reducing seizure frequency in patients with drug-resistant partial-onset seizures. Classification of evidence: This study provides Class II evidence that EZG(RTG) 1,200 mg/day is effective as adjunctive therapy in adults with partial-onset seizures with or without secondary generalization