Faculty Bibliography

BACKGROUND: Almost a third of patients with epilepsy have a treatment-resistant form, which is associated with severe morbidity and increased mortality. Cannabis-based treatments for epilepsy have generated much interest, but scientific data are scarce. We aimed to establish whether addition of cannabidiol to existing anti-epileptic regimens would be safe, tolerated, and efficacious in children and young adults with treatment-resistant epilepsy. METHODS: In this open-label trial, patients (aged 1-30 years) with severe, intractable, childhood-onset, treatment-resistant epilepsy, who were receiving stable doses of antiepileptic drugs before study entry, were enrolled in an expanded-access programme at 11 epilepsy centres across the USA. Patients were given oral cannabidiol at 2-5 mg/kg per day, up-titrated until intolerance or to a maximum dose of 25 mg/kg or 50 mg/kg per day (dependent on study site). The primary objective was to establish the safety and tolerability of cannabidiol and the primary efficacy endpoint was median percentage change in the mean monthly frequency of motor seizures at 12 weeks. The efficacy analysis was by modified intention to treat. Comparisons of the percentage change in frequency of motor seizures were done with a Mann-Whitney U test. RESULTS: Between Jan 15, 2014, and Jan 15, 2015, 214 patients were enrolled; 162 (76%) patients who had at least 12 weeks of follow-up after the first dose of cannabidiol were included in the safety and tolerability analysis, and 137 (64%) patients were included in the efficacy analysis. In the safety group, 33 (20%) patients had Dravet syndrome and 31 (19%) patients had Lennox-Gastaut syndrome. The remaining patients had intractable epilepsies of different causes and type. Adverse events were reported in 128 (79%) of the 162 patients within the safety group. Adverse events reported in more than 10% of patients were somnolence (n=41 [25%]), decreased appetite (n=31 [19%]), diarrhoea (n=31 [19%]), fatigue (n=21 [13%]), and convulsion (n=18 [11%]). Five (3%) patients discontinued treatment because of an adverse event. Serious adverse events were reported in 48 (30%) patients, including one death-a sudden unexpected death in epilepsy regarded as unrelated to study drug. 20 (12%) patients had severe adverse events possibly related to cannabidiol use, the most common of which was status epilepticus (n=9 [6%]). The median monthly frequency of motor seizures was 30.0 (IQR 11.0-96.0) at baseline and 15.8 (5.6-57.6) over the 12 week treatment period. The median reduction in monthly motor seizures was 36.5% (IQR 0-64.7). INTERPRETATION: Our findings suggest that cannabidiol might reduce seizure frequency and might have an adequate safety profile in children and young adults with highly treatment-resistant epilepsy. Randomised controlled trials are warranted to characterise the safety profile and true efficacy of this compound. FUNDING: GW Pharmaceuticals, Epilepsy Therapy Project of the Epilepsy Foundation, Finding A Cure for Epilepsy and Seizures.

PURPOSE: An emerging approach in medical genetics is to identify de novo mutations in patients with severe early-onset genetic disease that are absent in population controls and in the patient's parents. This approach, however, frequently misses post-zygotic "mosaic" mutations that are present in only a portion of the healthy parents' cells and are transmitted to offspring. METHODS: We constructed a mosaic transmission screen for variants that have an ~50% alternative allele ratio in the proband but are significantly less than 50% in the transmitting parent. We applied it to two family-based genetic disease cohorts consisting of 9 cases of sudden unexplained death in childhood (SUDC) and 338 previously published cases of epileptic encephalopathy. RESULTS: The screen identified six parental-mosaic transmissions across the two cohorts. The resultant rate of ~0.02 identified transmissions per trio is far lower than that of de novo mutations. Among these transmissions were two likely disease-causing mutations: an SCN1A mutation transmitted to an SUDC proband and her sibling with Dravet syndrome, as well as an SLC6A1 mutation in a proband with epileptic encephalopathy. CONCLUSION: These results highlight explicit screening for mosaic mutations as an important complement to the established approach of screening for de novo mutations.Genet Med advance online publication 30 December 2015Genetics in Medicine (2015); doi:10.1038/gim.2015.155.

Malformations of cortical development are found at higher rates in autism spectrum disorder (ASD) than in healthy controls on postmortem neuropathological evaluation but are more variably observed on visual review of in-vivo MRI brain scans. This may be due to the visually elusive nature of many malformations on MRI. Here, we utilize a quantitative approach to determine whether a volumetric measure of heterotopic gray matter in the white matter is elevated in people with ASD, relative to typically developing controls (TDC). Data from a primary sample of 48 children/young adults with ASD and 48 age-, and gender-matched TDCs, selected from the Autism Brain Imaging Data Exchange (ABIDE) open-access database, were analyzed to compare groups on (1) blinded review of high-resolution T1-weighted research sequences; and (2) quantitative measurement of white matter hypointensity (WMH) volume calculated from the same T1-weighted scans. Groupwise WMH volume comparisons were repeated in an independent, multi-site sample (80 ASD/80 TDC), also selected from ABIDE. Visual review resulted in equivalent proportions of imaging abnormalities in the ASD and TDC group. However, quantitative analysis revealed elevated periventricular and deep subcortical WMH volumes in ASD. This finding was replicated in the independent, multi-site sample. Periventricular WMH volume was not associated with age but was associated with greater restricted repetitive behaviors on both parent-reported and clinician-rated assessment inventories. Thus, findings demonstrate that periventricular WMH volume is elevated in ASD and associated with a higher degree of repetitive behaviors and restricted interests. Although the etiology of focal WMH clusters is unknown, the absence of age effects suggests that they may reflect a static anomaly.

Epilepsy is associated with a high rate of premature mortality from direct and indirect effects of seizures, epilepsy, and antiseizure therapies. Sudden unexpected death in epilepsy (SUDEP) is the second leading neurologic cause of total lost potential life-years after stroke, yet SUDEP may account for less than half of all epilepsy-related deaths. Some epilepsy groups are especially vulnerable: individuals from low socioeconomic status groups and those with comorbid psychiatric illness die more often than controls. Despite clear evidence of an important public health problem, efforts to assess and prevent epilepsy-related deaths remain inadequate. We discuss factors contributing to the underestimation of SUDEP and other epilepsy-related causes of death. We suggest the need for a systematic classification of deaths directly due to epilepsy (e.g., SUDEP, drowning), due to acute symptomatic seizures, and indirectly due to epilepsy (e.g., suicide, chronic effects of antiseizure medications). Accurately estimating the frequency of epilepsy-related mortality is essential to support the development and assessment of preventive interventions. We propose that educational interventions and public health campaigns targeting medication adherence, psychiatric comorbidity, and other modifiable risk factors may reduce epilepsy-related mortality. Educational campaigns regarding sudden infant death syndrome and fires, which kill far fewer Americans than epilepsy, have been widely implemented. We have done too little to prevent epilepsy-related deaths. Everyone with epilepsy and everyone who treats people with epilepsy need to know that controlling seizures will save lives.

Surface-based cortical thickness (CT) analyses are increasingly being used to investigate variations in brain morphology across the spectrum of brain health, from neurotypical to neuropathological. An outstanding question is whether individual differences in cortical morphology, such as regionally increased or decreased CT, are associated with domain-specific performance deficits in healthy adults. Since CT studies are correlational, they cannot establish causality between brain morphology and cognitive performance. A direct comparison with classic lesion methods is needed to determine whether the regional specificity of CT-cognition correlations is similar to that observed in patients with brain lesions. We address this question by comparing the neuroanatomical overlap of effects when 1) whole brain vertex-wise CT is tested as a correlate of performance variability on a commonly used neuropsychological test of executive function, Trailmaking Test Part B (TMT-B), in healthy adults and 2) voxel-based lesion-symptom mapping (VBLSM) is used to map lesion location to performance decrements on the same task in patients with frontal lobe lesions. We found that reduced performance on the TMT-B was associated with increased CT in bilateral prefrontal regions in healthy adults and that results spatially overlapped in the left dorsomedial prefrontal cortex with findings from the VBLSM analysis in patients with frontal brain lesions. Findings indicate that variations in the structural integrity of the left dorsomedial prefrontal lobe, ranging from individual CT differences in healthy adults to structural lesions in patients with neurological disorders, are associated with poor performance on the TMT-B. These converging results suggest that the left dorsomedial prefrontal region houses a critical region for the complex processing demands of TMT-B, which include visuomotor tracking, sequencing, and cognitive flexibility.

The male:female ratio in autism spectrum disorder (ASD) averages greater than 4:1 while the male:female ratio of ASD with epilepsy averages less than 3:1. This indicates an elevated risk of epilepsy in females with ASD; yet, it is unknown whether phenotypic features of epilepsy and ASD differ between males and females with this comorbidity. The goal of this study is to investigate sex differences in phenotypic features of epilepsy and ASD in a prospective sample of 130 children and young adults with an initial ASD diagnosis and subsequent epilepsy diagnosis. All participants were characterized by standardized diagnostic inventories, parent/caregiver completed questionnaires, and medical/academic record review. Diagnostic classifications of epilepsy, ASD, and intellectual disability were performed by board certified neurologists and a pediatric neuropsychologist. Results demonstrated a lower male:female ratio (1.8:1) in individuals with ASD and treatment-resistant epilepsy relative to those with ASD and treatment-responsive epilepsy (4.9:1), indicating a higher risk of treatment-resistant epilepsy in females. Mild neuroimaging abnormalities were more common in females than males and this was associated with increased risk of treatment-resistance. In contrast, ASD symptom severity was lower in females compared with males. Findings distinguish females with ASD and epilepsy as a distinct subgroup at higher risk for a more severe epilepsy phenotype in the context of a less severe ASD phenotype. Increased risk of anti-epileptic treatment resistance in females with ASD and epilepsy suggests that comprehensive genetic, imaging, and neurologic screening and enhanced treatment monitoring may be indicated for this subgroup. Autism Res 2015. (c) 2015 International Society for Autism Research, Wiley Periodicals, Inc.

The interplay between the brain's function and structure has been of immense interest to the neuroscience and connectomics communities. In this work we develop a simple linear model relating the structural network and the functional network. We propose that the two networks are related by the structural network's Laplacian up to a shift. The model is simple to implement and gives accurate prediction of function's eigenvalues at the subject level and its eigenvectors at group level

Purpose: Annegers et al. (2000) reported that the rate of sudden unexpected death in epilepsy (SUDEP) in patients undergoing VNS Therapy decreased from 5.5 per 1000 patient-years (PY) over the first 2 years to 1.7 per 1000 PY thereafter. Since that report, over 80,000 patients with drug-resistant epilepsy have been implanted worldwide, providing the opportunity to revisit the impact of VNS on SUDEP. Methods: This retrospective study included all US patients with drugresistant epilepsy who were implanted with VNS from 1988-2012 with known social security numbers. Exposure to VNS was calculated from date of implant until death, device explant, known date at which the device was disabled or the last follow-up date of December 31, 2012. Occurrence, date and cause of death were obtained from the Social Security Death Index Master File and the National Death Index, which provides ICD-9 or ICD-10 codes. A group of cause-of-death codes was selected as reflecting potential SUDEP and a sample categorized according to Annegers' SUDEP classification. Results: A total of 40,443 patients (mean age at implant: 30.8 years) with a median follow-up of 7.6 years, representing 277,661 PY, were included. A total of 3,689 deaths were recorded, translating into a 13.3/ 1000 PY all-cause mortality rate (SMR=4.58). 953(26%) corresponded to cause-of-death codes that potentially include SUDEP, with a decreasing trend as duration of VNS increased. A preliminary review of a random sample of 200 of these cases adjudicated 109 (54.5%) as possible/ probable/definite SUDEP (1.9/1000 PY). Conclusion: This large mortality study of patients with VNS therapy offers an 80 fold increase in available PY of follow-up as compared to published data. Preliminary findings show crude all-cause mortality rates consistent with those observed in drug-resistant epilepsy. Ongoing analyses will provide specific information regarding SUDEP risk and the impact of VNS therapy

Background: A combined PET/MR scanner with simultaneous acquisition allows direct correlations of PET data with MR-detected parameters on the same subject at the same time. This multi-modal analysis will facilitate the identification of an optimal biomarker. Here we report our study to compare dynamic SUV and cortical thickness between controls (HC) and epilepsy patients (Ep) using simultaneous PET/MR. Methods: Subjects (11 HC and 27 Ep) were imaged on a combined PET/MR scanner (Biograph muMR, Siemens). After FDG injection, dynamic PET scans and simultaneous MR imaging (including T1, T2 and other sequences) were acquired for ~90 minutes. Dixon sequence was acquired for attenuation correction. PET data were reconstructed using the e7tools provided by Siemens. Images were processed using Freesurfer, a fully automated image analysis tool. Over 100 masks (ROIs), including left and right, for cortical and subcortical regions were generated. Statistical analyses on mean SUV for entire study (SUVmean-all), meanSUV derived from the last three frames (SUVmean-late), and mean cortical thickness were compared between groups. Results: Based on Mann-Whitney U tests, SUVmean-late values showed significant differences between groups for most ROIs, while no difference was seen with SUVmean-all. Temporal-Mid-tempocci consistently showed significant difference when normalized SUV values were compared (p <0.01, by individual subject's mean cortical, white matter or global brain). Significant cortical thinning (Epi vs. HC) was detected bilaterally (left, right) within localized regions, such as precentral (p=0.017, 0.012) and superiorfrontal (p=0.016, 0.001). Binary logistic regression indicated that both SUVmean-late and cortical thickness were independent predictors for epilepsy. Conclusions: Our results suggest that simultaneous PET/ MR imaging provides a useful imaging tool to identify regional abnormality, and that SUVmean-late and cortical thickness are independent biomarkers for epilepsy