Faculty Bibliography

Adult neurogenesis, the generation of new neurons in the adult brain, occurs in the hippocampal dentate gyrus (DG) and the olfactory bulb (OB) of all mammals, but the functions of these new neurons are not entirely clear. Originally, adult-born neurons were considered to have excitatory effects on the DG network, but recent studies suggest a net inhibitory effect. Therefore, we hypothesized that selective removal of newborn neurons would lead to increased susceptibility to the effects of a convulsant. This hypothesis was tested by evaluating the response to the chemoconvulsant kainic acid (KA) in mice with reduced adult neurogenesis, produced either by focal X-irradiation of the DG, or by pharmacogenetic deletion of dividing radial glial precursors. In the first 4 hrs after KA administration, when mice have the most robust seizures, mice with reduced adult neurogenesis had more severe convulsive seizures, exhibited either as a decreased latency to the first convulsive seizure, greater number of convulsive seizures, or longer convulsive seizures. Nonconvulsive seizures did not appear to change or they decreased. Four-21 hrs after KA injection, mice with reduced adult neurogenesis showed more interictal spikes (IIS) and delayed seizures than controls. Effects were greater when the anticonvulsant ethosuximide was injected 30 min prior to KA administration; ethosuximide allows forebrain seizure activity to be more easily examined in mice by suppressing seizures dominated by the brainstem. These data support the hypothesis that reduction of adult-born neurons increases the susceptibility of the brain to effects of KA.

BACKGROUND: Despite the increasing interest in sex differences in disease manifestations and responses to treatment, very few data are available on sex differences in seizure types and semiology. The Epilepsy Phenome/Genome Project (EPGP) is a large-scale, multi-institutional, collaborative study that aims to create a comprehensive repository of detailed clinical information and DNA samples from a large cohort of people with epilepsy. We used this well-characterized cohort to explore differences in seizure types as well as focal seizure symptoms between males and females. METHODS: We reviewed the EPGP database and identified individuals with generalized epilepsy of unknown etiology (GE) (n = 760; female: 446, male: 314), nonacquired focal epilepsy (NAFE) (n = 476; female: 245, male: 231), or both (n = 64; female: 33, male: 31). Demographic data along with characterization of seizure type and focal seizure semiologies were examined. RESULTS: In GE, males reported atonic seizures more frequently than females (6.5% vs. 1.7%; p < 0.001). No differences were observed in other generalized seizure types. In NAFE, no sex differences were seen for seizure types with or without alteration of consciousness or progression to secondary generalization. Autonomic (16.4% vs. 26.6%; p = 0.005), psychic (26.7% vs. 40.3%; p = 0.001), and visual (10.3% vs. 19.9%; p = 0.002) symptoms were more frequently reported in females than males. Specifically, of psychic symptoms, more females than males endorsed deja vu (p = 0.001) but not forced thoughts, derealization/depersonalization, jamais vu, or fear. With corrections for multiple comparisons, there were no significant differences in aphasic, motor, somatosensory, gustatory, olfactory, auditory, vertiginous, or ictal headache symptoms between sexes. CONCLUSIONS: Significant differences between the sexes were observed in the reporting of atonic seizures, which were more common in males with GE, and for autonomic, visual, and psychic symptoms associated with NAFE, which were more common in females.

There is an urgent need for preclinical translational efforts to be realized as breakthroughs in therapy for the many patients with life-altering conditions affecting the CNS. Despite intensive efforts, few transformative therapies have emerged, and many new potential therapies that looked promising in preclinical development have failed in the clinic. In this Perspective, we suggest that if preclinical scientists partner early with clinical scientists, they can begin to envision the pathway forward for their work through clinical trials. Options might include determining the populations to be treated, issues of dose selection, timing of intervention, duration of intervention, and the availability of biomarkers. In addition, understanding other factors that impact the likelihood that a proof-of-concept trial can be performed, as well as other critical issues, will altogether increase the attractiveness of the project to investors and partners and will also increase the likelihood that the intervention will succeed in the clinic.

OBJECTIVE: We studied the frequency of auras in generalized epilepsy (GE) using a detailed semistructured diagnostic interview. METHODS: In this cross-sectional study, participants with GE were drawn from the Epilepsy Phenome/Genome Project (EPGP). Responses to the standardized diagnostic interview regarding tonic-clonic (grand mal) seizures were then examined. This questionnaire initially required participants to provide their own description of any subjective phenomena before their "grand mal seizures." Participants who provided answers to these questions were considered to have an aura. All participants were then systematically queried regarding a list of specific symptoms occurring before grand mal seizures, using structured (closed-ended) questions. RESULTS: Seven hundred ninety-eight participants with GE were identified, of whom 530 reported grand mal seizures. Of these, 112 (21.3%) reported auras in response to the open-ended question. Analysis of responses to the closed-ended questions suggested that 341 participants (64.3%) experienced at least one form of aura. CONCLUSIONS: Auras typically associated with focal epilepsy were reported by a substantial proportion of EPGP subjects with GE. This finding may support existing theories of cortical and subcortical generators of GE with variable spread patterns. Differences between responses to the open-ended question and closed-ended questions may also reflect clinically relevant variation in patient responses to history-taking and surveys. Open-ended questions may underestimate the prevalence of specific types of auras and may be in part responsible for the underrecognition of auras in GE. In addition, structured questions may influence participants, possibly leading to a greater representation of symptoms.

OBJECTIVE: Describe the characteristics of persons with epilepsy (PWEs) and caregivers that have or have not heard of sudden unexpected death in epilepsy (SUDEP) prior to completing a survey through the Internet or in the clinical setting. METHODS: An online survey for adult PWEs and caregivers was solicited by e-mail and newsletter to Epilepsy Therapy Project members. A similar survey was implemented in a clinic setting of a community hospital. The survey asked about seizure characteristics, epilepsy management, fear of death, and familiarity with the term SUDEP. Respondents that never heard of SUDEP read a definition and responded to questions about their initial reactions. RESULTS: Surveys from 1,392 PWEs and 611 caregivers recruited through an epilepsy Website and a clinic demonstrated that Internet respondents were much more likely to have heard about SUDEP than the clinic population (71.1% vs. 38.8%; p < 0.001), and caregivers of PWEs were more likely to have heard about SUDEP than PWEs (76.2% vs. 65.2%; p < 0.001). Prior awareness was related to an increased level of education, more severe and longer duration of epilepsy, and having an epileptologist as the primary care provider. Although most PWEs and caregivers reported feelings of fear, anxiety, and sadness after first hearing of SUDEP, they wanted to discuss it with their doctor. Persons with epilepsy, and especially their caregivers, often worry that the PWEs may die of epilepsy or seizures. This worry escalated with knowledge of SUDEP and increased epilepsy severity. Approximately half of PWEs and caregivers believed that knowledge about SUDEP would influence their epilepsy management. SIGNIFICANCE: Our results may help epilepsy care providers determine when to facilitate a discussion about epilepsy-related mortality and SUDEP among patients and caregivers, and to educate those at high risk about the importance of seizure control as well as reduce fears about death in patients with well-controlled and nonconvulsive epilepsies.

OBJECTIVES: To assess the efficacy and tolerability of add-on pregabalin controlled-release formulation (PGB-CR) (doses of 165 or 330 mg/day) in patients with partial-onset seizures (POS). METHODS: This was a randomized, double-blind (DB), parallel-group study of PGB-CR once-daily as adjunctive treatment in adults with treatment-resistant partial seizures. After an 8-week baseline period, eligible patients were randomized (1:1:1) to placebo, PGB-CR 165 mg, or PGB-CR 330 mg for 14 weeks, including a 2-week dose escalation. Primary endpoint was the loge -transformed 28-day seizure rate for all POS with observable component during the full 14-week double-blind treatment phase. Secondary endpoints included the 50% responder rate and percent change from baseline in 28-day POS rate. RESULTS: Three hundred twenty-three patients were randomized and received treatment; placebo (n = 110), PGB-CR 330 mg (n = 100), PGB-CR 165 mg (n = 113); and 287 (88.9%) completed the trial. The primary efficacy analysis result, expressed as percent reduction from placebo, was 13.1% and 1.0% for PGB-CR 330 mg and PGB-CR 165 mg, respectively, and was not statistically significant (p = 0.091, 0.908). The proportion of 50% responders was similar for placebo (35.8%) and 165 mg PGB-CR (37.8%) and nominally higher for 330 mg PGB-CR (45.9%, p = 0.125 compared to placebo). The LS mean estimates of the percent change from baseline for placebo (-5.7%) was nominally smaller than 165 mg PGB-CR (-15.0%, p = 0.540) and 330 mg PGB-CR (-31.5%, p = 0.079); however, the median percent changes from baseline were not as well differentiated (placebo, -35.4%; 165 mg PGB-CR, -38.0%; 330 mg PGB-CR -43.4%). Rates of adverse events (AEs) were low for placebo and study drug; the most frequent reported AEs were dizziness, somnolence, and fatigue, consistent with the immediate-release formulation. SIGNIFICANCE: Results from this trial did not demonstrate that PGB-CR is effective in reducing seizure frequency below that of placebo. Both doses of PGB-CR were shown to be safe and well-tolerated.

We present a patient with peritoneal carcinosarcoma who was treated with the alkylating agent ifosfamide and experienced a rapid decline in mental status. Electroencephalogram (EEG) displayed generalized periodic epileptiform discharges, which raised suspicion for nonconvulsive status epilepticus (NCSE). Following administration of midazolam, the patient's clinical condition and EEG improved. We review the 8 documented cases of ifosfamide-induced NCSE, and demonstrate the similarity in clinical features when compared with ifosfamide neurotoxicity that is not classified as NCSE. EEG findings suggesting an ictal pattern are subtle and heterogeneous, but they are essential for a diagnosis. Since it is unlikely that EEGs are uniformly obtained in instances of ifosfamide neurotoxicity, many cases of NCSE may go unrecognized.

IMPORTANCE: Sudden unexpected death in epilepsy (SUDEP) is a common cause of mortality in patients with the disease, but it is unknown how neurologists disclose this risk when counseling patients. OBJECTIVE: This study aimed at examining SUDEP discussion practices of neurologists in the U.S. and Canada. DESIGN: An electronic, web-based survey was sent to 17,558 neurologists in the U.S. and Canada. Survey questions included frequency of SUDEP discussion, reasons for discussing/not discussing SUDEP, timing of SUDEP discussions, and perceived patient reactions. We examined factors that influence the frequency of SUDEP discussion and perceived patient response using multivariate logistic regression. PARTICIPANTS: The participants of this study were neurologists who completed postgraduate training and devoted >5% of their time to patient care. RESULTS: There was a response rate of 9.3%; 1200 respondents met eligibility criteria and completed surveys. Only 6.8% of the respondents discussed SUDEP with nearly all (>90% of the time) of their patients with epilepsy/caregivers, while 11.6% never discussed it. Factors that independently predicted whether SUDEP was discussed nearly all of the time were the following: number of patients with epilepsy seen annually (OR=2.01, 95% CI=1.20-3.37, p<0.01) and if the respondent had a SUDEP case in the past 24months (OR=2.27, 95% CI=1.37-3.66, p<0.01). A majority of respondents (59.5%) reported that negative reactions were the most common response to a discussion of SUDEP. Having additional epilepsy/neurophysiology training was associated with an increased risk of a perceived negative response (OR=1.36, 95% CI=1.02-1.82, p=0.038), while years in practice (OR=0.85, 95% CI=0.77-0.95, p<0.005) and seeing both adults and children were associated with a decreased likelihood of negative response (OR=0.15, 95% CI=0.032-0.74, p=0.02). CONCLUSIONS: U.S. and Canadian neurologists rarely discuss SUDEP with all patients with epilepsy/caregivers though discussions are more likely among neurologists who frequently see patients with epilepsy or had a recent SUDEP in their practice. Perceived negative reactions to SUDEP discussions are common but not universal; more experienced neurologists may be less likely to encounter negative reactions, suggesting that there may be ways to frame the discussion that minimizes patient/caregiver distress.

To present a summary of current scientific evidence about the cannabinoid, cannabidiol (CBD) with regard to its relevance to epilepsy and other selected neuropsychiatric disorders. We summarize the presentations from a conference in which invited participants reviewed relevant aspects of the physiology, mechanisms of action, pharmacology, and data from studies with animal models and human subjects. Cannabis has been used to treat disease since ancient times. Delta9 -Tetrahydrocannabinol (Delta9 -THC) is the major psychoactive ingredient and CBD is the major nonpsychoactive ingredient in cannabis. Cannabis and Delta9 -THC are anticonvulsant in most animal models but can be proconvulsant in some healthy animals. The psychotropic effects of Delta9 -THC limit tolerability. CBD is anticonvulsant in many acute animal models, but there are limited data in chronic models. The antiepileptic mechanisms of CBD are not known, but may include effects on the equilibrative nucleoside transporter; the orphan G-protein-coupled receptor GPR55; the transient receptor potential of vanilloid type-1 channel; the 5-HT1a receptor; and the alpha3 and alpha1 glycine receptors. CBD has neuroprotective and antiinflammatory effects, and it appears to be well tolerated in humans, but small and methodologically limited studies of CBD in human epilepsy have been inconclusive. More recent anecdotal reports of high-ratio CBD:Delta9 -THC medical marijuana have claimed efficacy, but studies were not controlled. CBD bears investigation in epilepsy and other neuropsychiatric disorders, including anxiety, schizophrenia, addiction, and neonatal hypoxic-ischemic encephalopathy. However, we lack data from well-powered double-blind randomized, controlled studies on the efficacy of pure CBD for any disorder. Initial dose-tolerability and double-blind randomized, controlled studies focusing on target intractable epilepsy populations such as patients with Dravet and Lennox-Gastaut syndromes are being planned. Trials in other treatment-resistant epilepsies may also be warranted. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.