Faculty Bibliography

Awareness and research on epilepsy-related deaths (ERD), in particular Sudden Unexpected Death in Epilepsy (SUDEP), have exponentially increased over the last two decades. Most publications have focused on guidelines that inform clinicians dealing with these deaths, educating patients, potential risk factors and mechanisms. There is a relative paucity of information available for pathologists who conduct these autopsies regarding appropriate post mortem practice and investigations. As we move from recognizing SUDEP as the most common form of ERD toward in-depth investigations into its causes and prevention, health professionals involved with these autopsies and post mortem procedure must remain fully informed. Systematizing a more comprehensive and consistent practice of examining these cases will facilitate (i) more precise determination of cause of death, (ii) identification of SUDEP for improved epidemiological surveillance (the first step for an intervention study), and (iii) biobanking and cell-based research. This article reviews how pathologists and healthcare professionals have approached ERD, current practices, logistical problems and areas to improve and harmonize. The main neuropathology, cardiac and genetic findings in SUDEP are outlined, providing a framework for best practices, integration of clinical, pathological and molecular genetic investigations in SUDEP, and ultimately prevention.

Reliable posture labels in hospital environments can augment research studies on neural correlates to natural behaviors and clinical applications that monitor patient activity. However, many existing pose estimation frameworks are not calibrated for these unpredictable settings. In this paper, we propose a semi-automated approach for improving upper-body pose estimation in noisy clinical environments, whereby we adapt and build around an existing joint tracking framework to improve its robustness to environmental uncertainties. The proposed framework uses subject-specific convolutional neural network models trained on a subset of a patient's RGB video recording chosen to maximize the feature variance of each joint. Furthermore, by compensating for scene lighting changes and by refining the predicted joint trajectories through a Kalman filter with fitted noise parameters, the extended system yields more consistent and accurate posture annotations when compared with the two state-of-the-art generalized pose tracking algorithms for three hospital patients recorded in two research clinics.

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality in young adults. The exact mechanisms are unknown but death often follows a generalized tonic-clonic seizure. Proposed mechanisms include seizure-related respiratory, cardiac, autonomic, and arousal dysfunction. Genetic drivers underlying SUDEP risk are largely unknown. To identify potential SUDEP risk genes, we compared whole-exome sequences (WES) derived from formalin-fixed paraffin embedded surgical brain specimens of eight epilepsy patients who died from SUDEP with seven living controls matched for age at surgery, sex, year of surgery and lobe of resection. We compared identified variants from both groups filtering known polymorphisms from publicly available data as well as scanned for epilepsy and candidate SUDEP genes. In the SUDEP cohort, we identified mutually exclusive variants in genes involved in µ-opiod signaling, gamma-aminobutyric acid (GABA) and glutamate-mediated synaptic signaling, includingARRB2,ITPR1,GABRR2,SSTR5,GRIK1,CTNAP2,GRM8,GNAI2andGRIK5. In SUDEP patients we also identified variants in genes associated with cardiac arrhythmia, includingKCNMB1,KCNIP1,DPP6,JUP,F2, andTUBA3D, which were not present in living epilepsy controls. Our data shows that genomic analysis of brain tissue resected for seizure control can identify potential genetic biomarkers of SUDEP risk.

Animal studies support the hypothesis that in slow-wave sleep, replay of waking neocortical activity under hippocampal guidance leads to memory consolidation. However, no intracranial electrophysiological evidence for replay exists in humans. We identified consistent sequences of population firing peaks across widespread cortical regions during complete waking periods. The occurrence of these "Motifs" were compared between sleeps preceding the waking period ("Sleep-Pre") when the Motifs were identified, and those following ("Sleep-Post"). In all subjects, the majority of waking Motifs (most of which were novel) had more matches in Sleep-Post than in Sleep-Pre. In rodents, hippocampal replay occurs during local sharp-wave ripples, and the associated neocortical replay tends to occur during local sleep spindles and down-to-up transitions. These waves may facilitate consolidation by sequencing cell-firing and encouraging plasticity. Similarly, we found that Motifs were coupled to neocortical spindles, down-to-up transitions, theta bursts, and hippocampal sharp-wave ripples. While Motifs occurring during cognitive task performance were more likely to have more matches in subsequent sleep, our studies provide no direct demonstration that the replay of Motifs contributes to consolidation. Nonetheless, these results confirm a core prediction of the dominant neurobiological theory of human memory consolidation.

Purpose: Assess the effect of CBD added to antiepileptic drug (AED) therapy for the treatment of drug-resistant seizures in Dravet syndrome. Method: This double-blind, placebo-controlled trial randomised 120 children aged 2-18 years with Dravet syndrome and drug-resistant seizures to receive CBD oral solution 20 mg/kg/day (n = 61) or placebo (n = 59) for 14 weeks (2 week titration; 12 week maintenance). The primary endpoint was the percentage change from baseline in convulsive seizures (tonic-clonic, tonic, clonic, and atonic) frequency over the 14-week treatment period. Results: The groups were well-balanced at baseline for demographics. Mean age was 10 years, with 29% of patients <6 years. Patients had previously tried a median 4 AEDs, and were currently taking a median 3 AEDs. Convulsive seizure frequency per month decreased from a median of 12.4 to 5.9 (median reduction of 39%) with CBD vs. 14.9 to 14.1 (median reduction of 13%) with placebo (difference between groups of 23%; p = 0.012). The proportion of patients with >=50% reduction in convulsive seizure frequency was 42.6% with CBD vs. 27.1% with placebo (OR=2.0; p = 0.078). Adverse events (AEs) occurred in 93.4% of CBD and 74.6% of placebo patients, and were mostly mild or moderate; the most common were somnolence, diarrhea, and decreased appetite. Serious AEs were reported in 16.4% of CBD and 5.1% of placebo patients, and were considered treatment-related in 8.2% of CBD patients, all of whom discontinued CBD. Some elevations in transaminases were noted without elevations of bilirubin; all were on concomitant valproate and all resolved. There were no deaths in the study. Conclusion: Results from this study suggest that CBD add-on therapy for drug-resistant seizures in Dravet syndrome may be efficacious, with more AEs than placebo but generally well tolerated

BACKGROUND:Genetic variant interpretation contributes to testing yield differences reported for sudden unexplained death. Adapting a high-resolution variant interpretation framework, which considers disease prevalence, reduced penetrance, genetic heterogeneity, and allelic contribution to determine the maximum tolerated allele count in gnomAD, we report an evaluation of cardiac channelopathy and cardiomyopathy genes in a large, demographically diverse sudden unexplained death cohort that underwent thorough investigation in the United States' largest medical examiner's office. METHODS AND RESULTS/RESULTS:The cohort has 296 decedents: 147 Blacks, 64 Hispanics, 49 Whites, 22 Asians, and 14 mixed ethnicities; 142 infants (1 to 11 months), 39 children (1 to 17 years), 74 young adults (18 to 34 years), and 41 adults (35 to 55 years). Eighty-nine cardiac disease genes were evaluated. Using a high-resolution variant interpretation workflow, we classified 17 variants as pathogenic or likely pathogenic (2 of which were incidental findings and excluded in testing yield analysis), 46 novel variants of uncertain significance, and 130 variants of uncertain significance. Nine pathogenic or likely pathogenic variants in ClinVar were reclassified to likely benign and excluded in testing yield analysis. The yields of positive cases by ethnicity and age were 21.4% in mixed ethnicities, 10.2% Whites, 4.5% Asians, 3.1% Hispanics, and 2% Blacks; 7.7% children, 7.3% in adults, 5.4% young adults, and 2.8% infants. The percentages of uncertain cases with variants of uncertain significance by ethnicity were 45.5% in Asians, 45.3% Hispanics, 44.20% Blacks, 36.7% Whites, and 14.3% in mixed ethnicities. CONCLUSIONS:High-resolution variant interpretation provides diagnostic accuracy and healthcare efficiency. Under-represented populations warrant greater inclusion in future studies.

Purpose: Evaluate efficacy of add-on CBD for the treatment of seizures associated with LGS. Method: Eligible patients were 2-55 years old with a clinical diagnosis of LGS, >=8 drop seizures during 4-week baseline, and documented failure of >=1 antiepileptic drug (AED). Patients were randomised (1:1:1) to 20 mg/kg/day CBD, 10 mg/kg/day CBD, or placebo for 14 weeks (2-week titration; 12-week maintenance). The primary efficacy endpoint was percentage change from baseline in drop seizures/month over the 14-week treatment period for CBD vs. placebo; >=50% responder rate and percentage change in total seizures were assessed. Results: 225 patients were randomised (76 CBD 20 mg/kg, 73 CBD 10 mg/kg, 76 placebo); 9 CBD 20 mg/kg, 2 CBD 10 mg/kg, and 2 placebo patients withdrew. Groups were similar at baseline; mean age was 16 years (30% of patients >=18 years) and median drop seizures/month was 85 (IQR: 44, 168). Patients had failed a median of 6 and were taking a median of 3 AEDs. Reduction in drop seizures was significantly greater for CBD 20 mg/kg (42%) and CBD 10 mg/kg (37%) than placebo (17%; p = 0.0047 and p = 0.0016), as were >=50% responder rates (40% and 36% vs. 15%; p = 0.0006 and p = 0.0030) and reductions in total seizures (38% and 36% vs. 18%; p = 0.0091 and p = 0.0015). Adverse events (AEs) occurred in 94% of CBD 20 mg/kg, 84% of CBD 10 mg/kg, and 72% of placebo patients, and were mostly mild or moderate; the most common were somnolence and decreased appetite. Treatment-related serious AEs occurred in 5 CBD 20 mg/kg, 2 CBD 10 mg/kg, and 0 placebo patients. Some elevations in transaminases were seen. There were no deaths. Of 212 completers, 99% entered the open-label extension study. Conclusion: Results suggest that add-on CBD for treatment of seizures associated with LGS may be efficacious, with more adverse events than placebo, but generally well-tolerated

Purpose: Evaluate the dose-ranging safety, tolerability, and pharmacokinetics (PK) of CBD in children with Dravet syndrome (DS). Method: Patients aged 4-10 years completed a 4-week baseline period and were randomised 4:1 to 1 of 3 CBD doses (5, 10, 20 mg/kg/day) or placebo as add-on therapy for 3 weeks. CBD (25 or 100 mg/mL oral solution) was administered BID starting at 2.5 mg/kg/day and increasing by 2.5 mg/kg QOD to randomised dose. On Days 1 and 22, PK exposures were expressed as AUC0-t. Dose proportionality was assessed on Day 22 by regression analysis. Adverse events (AEs) were recorded daily. Results: 34 patients were randomised to CBD 5 mg/kg/day (n = 10), 10 mg/kg/day (n = 8), 20 mg/kg/day (n = 9), or placebo (n = 7). Patients took a median 3 antiepileptic drugs (AEDs). On Day 22, exposures to CBD and major metabolites increased dose-proportionally; there was minimal change in clobazam levels, but concentrations of clobazam's metabolite, N-clobazam, increased independent of CBD dose, except in patients on stiripentol. There was no demonstrable effect on other AEDs (valproic acid, topiramate, stiripentol, levetiracetam). Most common AEs (CBD vs. placebo) were pyrexia (22% vs. 0%), somnolence (19% vs. 14%), decreased appetite (19% vs. 0%), and sedation (15% vs. 0%). Treatment-related serious AEs occurred in 2 patients on CBD and discontinuations due to AEs occurred in 2 patients on CBD. Increases in ALT or AST (levels >3 9 ULN) occurred in 6 patients on CBD, all on valproic acid; none had elevated bilirubin and all recovered. Conclusion: CBD was well tolerated and 20 mg/kg/day was chosen for further development. Exposure to CBD and its metabolites increased dose-proportionally. A PK interaction of CBD on N-clobazam was observed, likely mediated through CYP2C19 inhibition, except with stiripentol, presumably from prior saturated inhibition of CYP2C19 by stiripentol