Faculty Bibliography

The classic epileptic encephalopathies, including infantile spasms (IS) and Lennox-Gastaut syndrome (LGS), are severe seizure disorders that usually arise sporadically. De novo variants in genes mainly encoding ion channel and synaptic proteins have been found to account for over 15% of patients with IS or LGS. The contribution of autosomal recessive genetic variation, however, is less well understood. We implemented a rare variant transmission disequilibrium test (TDT) to search for autosomal recessive epileptic encephalopathy genes in a cohort of 320 outbred patient-parent trios that were generally prescreened for rare metabolic disorders. In the current sample, our rare variant transmission disequilibrium test did not identify individual genes with significantly distorted transmission over expectation after correcting for the multiple tests. While the rare variant transmission disequilibrium test did not find evidence of a role for individual autosomal recessive genes, our current sample is insufficiently powered to assess the overall role of autosomal recessive genotypes in an outbred epileptic encephalopathy population

BACKGROUND: The Dravet syndrome is a complex childhood epilepsy disorder that is associated with drug-resistant seizures and a high mortality rate. We studied cannabidiol for the treatment of drug-resistant seizures in the Dravet syndrome. METHODS: In this double-blind, placebo-controlled trial, we randomly assigned 120 children and young adults with the Dravet syndrome and drug-resistant seizures to receive either cannabidiol oral solution at a dose of 20 mg per kilogram of body weight per day or placebo, in addition to standard antiepileptic treatment. The primary end point was the change in convulsive-seizure frequency over a 14-week treatment period, as compared with a 4-week baseline period. RESULTS: The median frequency of convulsive seizures per month decreased from 12.4 to 5.9 with cannabidiol, as compared with a decrease from 14.9 to 14.1 with placebo (adjusted median difference between the cannabidiol group and the placebo group in change in seizure frequency, -22.8 percentage points; 95% confidence interval [CI], -41.1 to -5.4; P=0.01). The percentage of patients who had at least a 50% reduction in convulsive-seizure frequency was 43% with cannabidiol and 27% with placebo (odds ratio, 2.00; 95% CI, 0.93 to 4.30; P=0.08). The patient's overall condition improved by at least one category on the seven-category Caregiver Global Impression of Change scale in 62% of the cannabidiol group as compared with 34% of the placebo group (P=0.02). The frequency of total seizures of all types was significantly reduced with cannabidiol (P=0.03), but there was no significant reduction in nonconvulsive seizures. The percentage of patients who became seizure-free was 5% with cannabidiol and 0% with placebo (P=0.08). Adverse events that occurred more frequently in the cannabidiol group than in the placebo group included diarrhea, vomiting, fatigue, pyrexia, somnolence, and abnormal results on liver-function tests. There were more withdrawals from the trial in the cannabidiol group. CONCLUSIONS: Among patients with the Dravet syndrome, cannabidiol resulted in a greater reduction in convulsive-seizure frequency than placebo and was associated with higher rates of adverse events. (Funded by GW Pharmaceuticals; ClinicalTrials.gov number, NCT02091375 .).

Intellectual disability (ID) affects about 3% of the population and has a male gender bias. Of at least 700 genes currently linked to ID, more than 100 have been identified on the X chromosome, including KIAA2022. KIAA2022 is located on Xq13.3 and is expressed in the developing brain. The protein product of KIAA2022, X-linked Intellectual Disability Protein Related to Neurite Extension (XPN), is developmentally regulated and is involved in neuronal migration and cell adhesion. The clinical manifestations of loss-of-function KIAA2022 mutations have been described previously in fifteen males, born from unaffected carrier mothers, but few females. Using whole exome sequencing, we identified a cohort of five unrelated female patients with de novo likely gene damaging variants in KIAA2022 and core phenotypic features of intellectual disability, developmental delay, epilepsy refractory to treatment, and impaired language, of similar severity as reported for male counterparts. This study supports KIAA2022 as a novel cause of X-linked dominant intellectual disability, and broadens the phenotype for KIAA2022 mutations.

Treatment-resistant epilepsy (TRE) affects 30% of epilepsy patients and is associated with severe morbidity and increased mortality. Cannabis-based therapies have been used to treat epilepsy for millennia, but only in the last few years have we begun to collect data from adequately powered placebo-controlled, randomized trials (RCTs) with cannabidiol (CBD), a cannabis derivative. Previously, information was limited to case reports, small series, and surveys reporting on the use of CBD and diverse medical marijuana (MMJ) preparations containing: tetrahydrocannabinol (THC), CBD, and many other cannabinoids in differing combinations. These RCTs have studied the safety and explored the potential efficacy of CBD use in children with Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS). The role of the placebo response is of paramount importance in studying medical cannabis products given the intense social and traditional media attention, as well as the strong beliefs held by many parents and patients that a natural product is safer and more effective than FDA-approved pharmaceutical agents. We lack valid data on the safety, efficacy, and dosing of artisanal preparations available from dispensaries in the 25 states and District of Columbia with MMJ programs and online sources of CBD and other cannabinoids. On the other hand, open-label studies with 100mg/ml CBD (Epidiolex®, GW Pharmaceuticals) have provided additional evidence of its efficacy along with an adequate safety profile (including certain drug interactions) in children and young adults with a spectrum of TREs. Further, Phase 3 RCTs with Epidiolex support efficacy and adequate safety profiles for children with DS and LGS at doses of 10- and 20-mg/kg/day. This article is part of a Special Issue titled "Cannabinoids and Epilepsy".

The differential contribution of medial-temporal lobe regions to verbal declarative memory is debated within the neuroscience, neuropsychology, and cognitive psychology communities. We evaluate whether the extent of surgical resection within medial-temporal regions predicts longitudinal verbal learning and memory outcomes. This single-center retrospective observational study involved patients with refractory temporal lobe epilepsy undergoing unilateral anterior temporal lobe resection from 2007 to 2015. Thirty-two participants with Engel Classes 1 and 2 outcomes were included (14 left, 18 right) and followed for a mean of 2.3 years after surgery (+/-1.5 years). Participants had baseline and postsurgical neuropsychological testing and high-resolution T1-weighted MRI scans. Postsurgical lesions were manually traced and coregistered to presurgical scans to precisely quantify resection extent of medial-temporal regions. Verbal learning and memory change scores were regressed on hippocampal, entorhinal, and parahippocampal resection volume after accounting for baseline performance. Overall, there were no significant differences in learning and memory change between patients who received left and right anterior temporal lobe resection. After controlling for baseline performance, the extent of left parahippocampal resection accounted for 27% (p = .021) of the variance in verbal short delay free recall. The extent of left entorhinal resection accounted for 37% (p = .004) of the variance in verbal short delay free recall. Our findings highlight the critical role that the left parahippocampal and entorhinal regions play in recall for verbal material.

The North American SUDEP Registry (NASR) is a repository of clinical data and biospecimens in cases of sudden unexpected death in epilepsy (SUDEP), a leading cause of epilepsy-related deaths. We assessed whether bereaved families were aware of SUDEP before their family member's death and their preferences for SUDEP disclosure. At enrollment, next-of-kin of SUDEP cases completed an intake interview, including questions assessing premorbid SUDEP discussions. Only 18.1% of the 138 next-of-kin recalled a previous discussion of SUDEP with a healthcare provider or support resource. Of the 112 who did not recall such a discussion, 72.3% wished it was discussed, 10.7% were satisfied it was not discussed, and 17% were unsure. A history of status epilepticus predicted SUDEP discussion. Rates of SUDEP discussion were not significantly higher among SUDEPs after 2013 (the approximate study midpoint) compared with those before then. Our study suggests that SUDEP remains infrequently discussed with family members of persons with epilepsy. Nearly three-quarters of family members wished they had known of SUDEP before the death. However, some were indifferent or were satisfied that this discussion had not occurred. We must balance more systematic education of patients and families about SUDEP while respecting individual preferences about having this discussion.

OBJECTIVE: Amygdala enlargement (AE) is observed in patients with temporal lobe epilepsy (TLE), which has led to the suggestion that it represents a distinct TLE subtype; however, it is unclear whether AE is found at similar rates in other epilepsy syndromes or in healthy controls, which would limit its value as a marker for focal epileptogenicity. METHODS: We compared rates of AE, defined quantitatively from high-resolution T1-weighted MRI, in a large multi-site sample of 136 patients with nonlesional localization related epilepsy (LRE), including TLE and extratemporal (exTLE) focal epilepsy, 34 patients with idiopathic generalized epilepsy (IGE), and 233 healthy controls (HCs). RESULTS: AE was found in all groups including HCs; however, the rate of AE was higher in LRE (18.4%) than in IGE (5.9%) and HCs (6.4%). Patients with unilateral LRE were further evaluated to compare rates of concordant ipsilateral AE in TLE and exTLE, with the hypothesis that rates of ipsilateral AE would be higher in TLE. Although ipsilateral AE was higher in TLE (19.4%) than exTLE (10.5%), this difference was not significant. Furthermore, among the 25 patients with unilateral LRE and AE, 13 (52%) had either bilateral AE or AE contralateral to seizure onset. CONCLUSION: Results suggest that AE, as defined with MRI volumetry, may represent an associated feature of nonlesional localization related epilepsy with limited seizure onset localization value.

PURPOSE: We examined the incidence of seizures following ischemic stroke in a community-based sample. METHODS: All subjects with incident ischemic strokes in the Framingham Original and Offspring cohorts between 1982 and 2003 were identified and followed for up to 20 years to determine incidence of seizures. Seizure-type was based on the 2010 International League Against Epilepsy (ILAE) classification. Disability was stratified into mild/none, moderate and severe, based on post-stroke neurological deficit documentation according to the Framingham Heart Study (FHS) protocol and functional status was determined using the Barthel Index. RESULTS: An initial ischemic stroke occurred in 469 subjects in the cohort and seizures occurred in 25 (5.3%) of these subjects. Seizure incidence was similar in both large artery atherosclerosis (LAA) (6.8%) and cardio-embolic (CE) (6.2%) strokes. No seizures occurred following lacunar strokes. The predominant seizure type was focal seizure with or without evolution to bilateral convulsive seizure. One third of participants had seizures within the first 24h from stroke onset and half of all seizures occurred within the first 30days. On multivariate analysis, moderate and severe disability following stroke was associated with increased risk of incident seizure. CONCLUSIONS: Seizures occurred in approximately 5% of subjects after an ischemic stroke. One third of these seizures occurred in the first 24h after stroke and none followed lacunar strokes. Focal seizures with or without evolution in bilateral convulsive seizures were the most common seizure type. Moderate and severe disability was predictive of incident seizures.

Objective: To compare the duration for which pediatric patients with refractory epilepsy who were started on these respective dietary treatments remained in treatment in this single-center cohort Background: The ketogenic diet (KD) is an effective treatment for refractory childhood epilepsy but its restrictiveness has limited widespread use. More recently, a modified Atkins diet (MAD) has been shown to similarly induce ketosis with fewer dietary and lifestyle restrictions. In practice, the benefits of both diets are limited by high discontinuation rates. Whether the less restrictive MAD is correlated with longer treatment adherence is unclear. Design/Methods: From 1/2010 - 6/2015, 148 children with refractory epilepsy were initiated on the classic KD (N=70) or MAD (N=78) in a non-randomized fashion as selected by their caretakers with support from the center's dietitians. Data was collected via retrospective chart review. We performed a Kaplan-Meier survival analysis comparing number of days maintained on the two diets, with further stratification by feeding mode and treatment response (as defined by >=50% reduction in seizure frequency). Results: Patients remained on the classic KD on average 638 +/-490 days, and MAD 348 +/-310 days (Mann-Whitney p<0.001). The mean age of children starting KD was 4 +/-3.9 vs. 8 +/-3.8 for MAD (Mann-Whitney p<0.001). Children assigned to MAD had a lower rate of delayed feeding skills (6.4% vs. 60.9% in KD group; Fisher's exact p <0.001). The 34 patients who were exclusively formula-fed stayed on the classic KD for 614 +/-562 days. When comparing only patients eating solid foods, adherence to KD was longer still (678 +/-411 days vs. 348 +/-310 days; logrank p<0.001. The trend remained when comparing only those with at least 50% treatment response, though sample sizes were small (logrank p=0.120). Conclusions: Further studies are needed to better understand the cause for earlier MAD discontinuation