Risk factors associated with drug resistant focal epilepsy in adults: A case control study.

PURPOSE: Using an adult cohort of patients with focal epilepsy, we aimed to identify risk factors for development of drug-resistant epilepsy, which if identifiable would allow patients to receive appropriate counsel and earlier surgical treatment. METHODS: This is a case-control study nested within a cohort, 146 adult patients with focal epilepsy were included. Definitions were used in accordance with ILAE criteria. The odds ratio and its confidence interval were calculated. We performed a logistic regression analysis. RESULTS: Seventy-one [48.6%] patients met the criteria for drug-resistant epilepsy [cases] and 75 [51.4%] patients were controls. The mean age of patients was 44.5 ± 16.4 years. The most significant variables associated with developing drug-resistant epilepsy include younger age at diagnosis [18.75 vs. 32.2, p < 0.001], years of evolution of epilepsy [22.54 vs. 16.05, p < 0.001], number of AED [4.8 vs. 2.87, p < 0.001], complex partial seizures [51 vs. 35 OR 2.9, p = 0.002], having more than one seizure per month [51 vs. 38, p = 0.009], bi-temporal focus [14 vs. 4 p = 0.008] and mesial temporal sclerosis [23 vs. 11 p = 0.01]. Good response to first AED [7 vs. 29 OR 0.2, p = 0.001] and epilepsy secondary to encephalomalacia [8 vs. 20 OR 0.35, p = 0.018] might be protective factors against drug resistant epilepsy. CONCLUSIONS: Longer time of epilepsy evolution, high frequency of seizures, complex partial seizure presentation, higher number of antiepileptic drugs, mesial temporal sclerosis and bitemporal epilepsy are predictive factors of subsequent pharmacoresistance.

A comparison of waiting times for assessment and epilepsy surgery between a Canadian and a Mexican referral center.

Objective: To provide a comprehensive transnational overview of wait times for epilepsy surgery in Canada and Mexico. Methods: We reviewed all cases referred for epilepsy surgery between 2007 and 2015 at the Saskatchewan Epilepsy Program Royal University Hospital (SEP) (n = 70; Saskatoon, Canada) and the National Institute of Neurology and Neurosurgery (NINN) (n = 76; Mexico City, Mexico) and compared wait times, calculated as the time from diagnosis of epilepsy on assessment at an epilepsy center to epilepsy surgery. Results: Mean wait times were similar across centers. Mean patient age was 37.4 ± 9 years (NINN) and 36.7 ± 13.2 years (SEP). The mean time from epilepsy diagnosis to referral was 18.9 (NINN) and 16.9 years (SEP), p = 0.30; first consult with the epileptologist, 19.7 (NINN) and 17.4 years (p = 0.23); neuropsychology consult, 21.4 (NINN) and 17.9 years (SEP); video electroencephalogram (video-EEG) telemetry, 21.1 (NINN) and 18.6 months (SEP); initial neurosurgical consult, 21.9 (NINN) and 19.1 years (SEP) (p = 0.35); and epilepsy surgery, 19.7 (NINN) and 19.6 years (SEP) (p = 0.29). Significance: This is the first study to compare wait times between Canada and Mexico. Despite disparity in their health delivery systems and financial resources, surgical wait times appeared to be protracted in both nations, confirming that delayed treatment is a universal problem that requires collaborative scrutiny.

Discontinuation of antiepileptic drugs after successful epilepsy surgery. a Canadian survey.

INTRODUCTION: To identify the perceived practice among Canadian epileptologists regarding discontinuation of antiepileptic drugs (AEDs) following successful resective surgery for temporal and extratemporal surgery. METHODS: We performed a survey of pediatric and adult epileptologists in Canada, using a 77-item questionnaire to explore attitudes, timing, rate of withdrawal, and factors contributing to the decision to withdraw AEDs after successful epilepsy surgery. Surveys were mailed with a postage-paid return envelope. Two subsequent surveys were mailed to non-respondents at 15 days intervals. All procedures received institutional review board approval. RESULTS: Surveys were sent to 82 epileptologists in all the Canadian provinces. Sixty-six physicians answered the survey (80.5%), representing all epilepsy centers across Canada. The minimum seizure free period required after epilepsy surgery before withdrawing AEDs, varied substantially among responders: <6 months in 10%, 6-11 months in 21%, >1 year in 50%, >2 years in 12%, >2 years in 3% after. The most important factors influencing the decision to withdraw AEDs a negative EEG before discontinuation (71%), patients' preferences (78%) and the presence of unilateral mesial temporal sclerosis (70%). The most important factors against reduction were the following: patients' wishes to resume driving (67%), focal (65%) or generalized (78%) epileptiform activity on EEG after surgery, persistent isolated auras (78%), any seizures after hospital discharge (81%), and presurgical multifocal/bilateral/diffuse findings (78%). DISCUSSION: Canadian epileptologists indicated that AED levels, EEG and MRI are typically done before discontinuing AEDs. Generally, a good candidate for stopping AEDs has focal pathology, is completely seizure free, had an anterior temporal lobe resection, complete resection of seizure focus, and has no epileptiform discharges on postoperative EEG. The data pertaining to self-reported practice styles, and actual practice may differ.

Sudden unexpected death in epilepsy: evidence-based analysis of incidence and risk factors.

PURPOSE: To provide an evidence-based analysis of the risk factors and incidence of SUDEP, and to assess methodological aspects and sources of variation in studies dealing with SUDEP. METHODS: An expert in library resources and electronic databases comprehensively searched Medline, Index Medicus, and the Cochrane library. We included case-control or cohort studies focusing on SUDEP in children or adults, published in the English language. Two reviewers independently applied study eligibility criteria and extracted data, resolving disagreements through discussion. RESULTS: Of 404 citations identified, 83 potentially eligible articles were reviewed in full text and 36 studies fulfilled eligibility criteria (29 cohort and 8 case-control studies). In studies using non-SUDEP deaths as controls the most consistent risk factors were a seizure preceding death, and subtherapeutic antiepileptic drug levels. In studies that used persons living with epilepsy as controls the main risk factors for SUDEP were youth, high seizure frequency, high number of antiepileptic drugs and long duration of epilepsy. The annual incidence of SUDEP ranged from 0 to 10:1000. It was highest in studies of candidates for epilepsy surgery and epilepsy referral centers (2.2:1000-10:1000), intermediate in studies including patients with mental retardation (3.4:1000-3.6:1000), and lowest in children (0-0.2:1000). The incidence was similar in autopsy series (0.35:1000-2.5:1000) and in studies of epilepsy patients in the general population (0-1.35:1000). The median proportion of SUDEP in relation to overall mortality in epilepsy was 40 and 4% in high- and low-risk groups, respectively. CONCLUSIONS: Although studies on SUDEP are heterogeneous in methodology, consistent patterns in incidence and risk factors emerge. Low- and high-risk patient groups are identified, which determine the relative contribution of SUDEP to overall mortality in epilepsy. In addition to patient population, risk factors for SUDEP depend on the type of controls used for comparison (dead versus live patients with epilepsy). Risk factors found in different studies are not necessarily contradictory, but are often complementary.