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Despite its effectiveness, surgery for drug-resistant epilepsy is underutilized. However, whether epilepsy surgery is also underutilized among patients with stroke-related drug-resistant epilepsy is unclear. Therefore, our objectives were to estimate the rates of epilepsy surgery assessment and receipt among patients with stroke-related drug-resistant epilepsy and to identify factors associated with these outcomes.
We used linked health administrative databases to conduct a population-based retrospective cohort study of adult Ontario, Canada residents discharged from an Ontario acute care institution following the treatment of a stroke between January 1, 1997, and December 31, 2020, without prior evidence of seizures. We excluded patients who did not subsequently develop drug-resistant epilepsy and those with other epilepsy risk factors. We estimated the rates of epilepsy surgery assessment and receipt by March 31, 2021. We planned to use Fine-Gray subdistribution hazard models to identify covariates independently associated with our outcomes, controlling for the competing risk of death.
We identified 265,081 patients who survived until discharge following inpatient stroke treatment, 1,902 (0.7%) of whom subsequently developed drug-resistant epilepsy (805 women; mean age: 67.0 ± 13.1 years). Fewer than six (≤0.3%) of these patients were assessed for or received epilepsy surgery before the end of follow-up (≤55.5 per 100,000 person-years). Given that few outcomes were identified, we could not proceed with the multivariable analyses.
Patients with stroke-related drug-resistant epilepsy are infrequently considered for epilepsy surgery that could reduce morbidity and mortality.
To describe the experience with Anterior Nucleus of the Thalamus-Deep Brain Stimulation (ANT-DBS) for the treatment of epilepsy at a Canadian Center.
All patients who underwent ANT-DBS implantation between 2013 (first patient implanted at our center) and 2020 were included. These patients had therapy-resistant epilepsy (TRE), were not candidates for resective surgery, and failed vagus nerve stimulation (VNS) treatment. Baseline of monthly seizure frequency was calculated within 3 months prior to VNS placement. Monthly seizure frequency was assessed at different points along the timeline: 3 months before ANT-DBS implantation as well as 3, 6, 12, 24, 36, 48, 60, and 72 months after ANT-DBS device placement. At each time point, seizure frequency was compared to baseline.
Six patients were implanted with ANT-DBS. Three (50%) patients had multifocal epilepsy, one (16.6%) had focal epilepsy, and two (33.4%) had combined generalized and focal epilepsy. Two patients with multifocal epilepsy experienced a seizure reduction >50% in the long-term follow-up. Three (50%) patients did not showed improvement: two with combined generalized and focal epilepsy and one with focal epilepsy. There were not surgical or device-related side effects. Two (33.3%) patients presented mild and transient headaches as a stimulation-related side effect.
ANT-DBS is an effective and safe treatment for focal TRE. Our experience suggests that patients with multifocal epilepsy due to regional lesion may benefit from ANT-DBS the most. Further investigations are required to determine optimal parameters of stimulation.
“Temporal plus” epilepsy (TPE) is a term that is used when the epileptogenic zone (EZ) extends beyond the boundaries of the temporal lobe. Stereotactic electroencephalography (SEEG) has been essential to identify additional EZs in adjacent structures that might be part of the temporal lobe/limbic network.
We present a small case series of temporal plus cases successfully identified by SEEG who were seizure-free after resective surgery.
We conducted a retrospective analysis of 156 patients who underwent SEEG in 5 years. Six cases had TPE and underwent anterior temporal lobectomy (ATL) with additional extra-temporal resections.
Five cases had a focus on the right hemisphere and one on the left. Three cases were non-lesional and three were lesional. Mean follow-up time since surgery was 2.9 years (SD ± 1.8). Three patients had subdural electrodes investigation prior or in addition to SEEG. All patients underwent standard ATL and additional extra-temporal resections during the same procedure or at a later date. All patients were seizure-free at their last follow-up appointment (Engel Ia = 3; Engel Ib = 2; Engel Ic = 1). Pathology was nonspecific/gliosis for all six cases.
TPE might explain some of the failures in temporal lobe epilepsy surgery. We present a small case series of six patients in whom SEEG successfully identified this phenomenon and surgery proved effective.
In Canada, recreational use of cannabis was legalized in October 2018. This policy change along with recent publications evaluating the efficacy of cannabis for the medical treatment of epilepsy and media awareness about its use have increased the public interest about this agent. The Canadian League Against Epilepsy Medical Therapeutics Committee, along with a multidisciplinary group of experts and Canadian Epilepsy Alliance representatives, has developed a position statement about the use of medical cannabis for epilepsy. This article addresses the current Canadian legal framework, recent publications about its efficacy and safety profile, and our understanding of the clinical issues that should be considered when contemplating cannabis use for medical purposes.
Creutzfeldt-Jakob disease (CJD) is a fatal neurological illness for which accurate diagnosis is paramount. Real-time quaking-induced conversion (RT-QuIC) is a prion-specific assay with high sensitivity and specificity for CJD. The Canadian endpoint quaking-induced conversion (EP-QuIC) test is similar, but unlike RT-QuIC there is little data regarding its diagnostic utility in clinical practice. In this exploratory predictive value analysis of EP-QuIC in CJD, the negative predictive value (NPV) and positive predictive value (PPV) was 100% and 83%, respectively, with one false-positive result identified. Re-testing this sample with an optimized EP-QuIC protocol eliminated this false-positive result, leading to a PPV of 100%.
At the London Health Sciences Centre Epilepsy Program, stereotactically implanted depth electrodes have largely replaced subdural electrodes in the presurgical investigation of patients with drug-resistant epilepsy over the past 4 years. The rationale for this paradigm shift was more experience with, and improved surgical techniques for, stereoelectroencephalography, a possible lower-risk profile for depth electrodes, better patient tolerability, shorter operative time, as well as increased recognition of potential surgical targets that are not accessible to subdural electrodes.
Rationale: Presurgical localization of the epileptogenic focus is critical to successful surgery. Traditionally, localization of the epileptogenic focus depends on seizure semiology, scalp video-electroencephalography (vEEG), magnetic resonance imaging (MRI), neuropsychological assessment, and, when needed, intracranial EEG (iEEG). We aimed to explore the role of positron emission tomography (PET) in the presurgical evaluation of patients with refractory epilepsy. Methods: A retrospective review was conducted on patients from London Health Sciences Centre (London, Ontario) with refractory epilepsy who underwent PET from September of 2011 to April of 2016. The accuracy of epileptogenic focus localization was compared between different investigative modalities (MRI, vEEG, iEEG, PET), and the outcomes were documented, including seizure freedom after surgical resection, improvement of seizure frequency, guidance for further investigations, and exclusion of patients from further evaluation. Patients who underwent surgery were followed up at 3 months and onward. Results: We identified 62 patients with refractory epilepsy who underwent PET. The mean age was 34 years (range=20-68). A total of 36 had concordant PET and vEEG findings: 6 had surgical resection and either became seizure-free (29.4%) or had improvement in seizure frequency (5.9%) at 3 months; 11 had surgical resection and either became seizure-free (29.4%) or had improvement in seizure frequency (35.3%) at 3 months, but required iEEG for final verification. Conclusions: PET has an important role in presurgical evaluation of patients with refractory epilepsy. It may allow resection of the epileptogenic focus without the need for iEEG, guiding intracranial electrode placement for further localization of the epileptogenic focus, or exclusion of patients from further evaluation.
Background: Approximately 30% of patients with epilepsy have medically intractable seizures, and a proportion of them are candidates for surgical treatment. The efficacy and safety of epilepsy surgery have been supported by a large number of studies, yet only a small minority of such patients in Ontario receive surgery. Methods: Family physicians in Ontario were surveyed regarding demographics, referral practices and general knowledge about epilepsy surgery. Four hundred surveys were mailed to randomly selected family physicians using contact information from the College of Physicians and Surgeons of Ontario website. Results: The response rate was 50%. The majority of family physicians (81%) always refer patients with epilepsy, most often to neurologists. General knowledge of epilepsy was mixed, with 53.7% feeling that surgery should be considered in selected cases for the treatment of epilepsy, though 53.2% did not know what type of epilepsy could be surgically treated. Conclusions: The results suggest a relatively low level of knowledge among family physicians in terms of when surgery ought to be considered, the types of epilepsy that are amenable to surgical treatment and the risks and benefits of epilepsy surgery. A lack of knowledge in these areas may partly underlie the low referral rates of epilepsy patients, though the results show that the majority of family physicians refer their patients with epilepsy to neurologists. Other factors must be considered, such as access to neurologists, epileptologists and surgical resources. Education campaigns directed at family physicians may improve knowledge and change referral practices. Future studies need to examine these possibilities.
The role of fludeoxyglucose F 18 positron emission tomography (PET) in the presurgical evaluation of patients with medically intractable epilepsy continues to be refined. The purpose of this study was to systematically review the literature to assess the diagnostic accuracy and utility of PET in this setting. Thirty-nine studies were identified through MEDLINE and EMBASE databases that met the inclusion criteria. In adult patients, PET hypometabolism showed a 56 to 90% agreement with seizure onset localized by intracranial electroencephalogram (pediatric: 21 to 86%). In temporal lobe epilepsy patients with good surgical outcome, PET displayed moderate to high sensitivity in localizing the seizure focus (range: 71 to 89%). The sensitivity increased by 8 to 23% when PET results were combined with magnetic resonance imaging or electroencephalogram. PET has been shown to affect patient management by improving the guidance of intracranial electrodes placement, altering the decision to perform surgery, or excluding patients from further evaluation.
Rasmussen's encephalitis is a progressive disease characterized by severe progressive neurological and cognitive deficits. It is a difficult condition to treat with conventional medical treatment and requires, in most of the cases, surgical intervention.
We present the case of a patient with Rasmussen's encephalitis who presented with epilepsia partialis continua, who did not respond to antiepileptic treatment and was evaluated for possible surgical intervention.
The electroencephalographic studies revealed bihemispheric involvement during seizures, although magnetic resonance imaging (MRI) showed a marked right hemispheric atrophy. Hyperperfusion over the right hemisphere was seen with the performance of ictal single photon emission computed tomography (SPECT), which finally guided a right functional hemispherectomy and subsequent seizure control.
Ictal SPECT could be a useful tool in the armamentarium of tools used for the localization of the epileptogenic focus in patients with Rasmussen's encephalitis and other localization-related epilepsies.
Invasive monitoring for the investigation of medically intractable epilepsy may be associated with undesirable morbidity. We performed a review of our recent experience to determine the incidence of major complications.
We reviewed the clinical records of all patients who underwent invasive EEG monitoring at our institution between 2000 and 2004.
One-hundred and sixteen patients (57 males, 59 females) with a mean age of 32 years of age underwent intracranial placement of electrodes for epilepsy surgery investigation. Subdural strips were placed in 115 patients with a mean of eight strips per patient. Subdural grids were inserted in 11 patients and depth electrodes in five. Fourteen of the 15 patients with grids or depth electrodes also had strips. Coverage was unilateral in 37 patients and bilateral in 79 patients. Electrodes were placed over the frontal lobe in 78 cases, temporal in 93, parietal in 24, and occipital in 27 patients. The average duration of investigation was 12.3 days (range 3-29). The evaluation led to the performance of a surgical resection in 85 patients (74%). Complications were seen in four patients with subdural strips (3%), and in two patients with grids (13%), characterized by clinical infection, intracranial hemorrhage, aseptic meningitis, transient neurological deficits, and status epilepticus. Mortality was nil.
In comparison with previously published literature on the topic, the major complication rate in this group of patients appears to be low.
Epilepsy is a common medical condition for which physicians perform driver fitness assessments. The Canadian Medical association (CMA) and the Canadian Council of Motor transportation administrators (CCMTA) publish documents to guide Canadian physicians’ driver fitness assessments.
We aimed to measure the consistency of driver fitness counseling among epileptologists in Canada, and to determine whether inconsistencies between national guidelines are associated with greater variability in counseling instructions.
We surveyed 35 epileptologists in Canada (response rate 71%) using a questionnaire that explored physicians’ philosophies about driver fitness assessments and counseling practices of seizure patients in common clinical scenarios. Of the nine scenarios, CCMTA and CMA recommendations were concordant for only two. Cumulative agreement for all scenarios was calculated using Kappa statistic. Agreement for concordant (two) vs. discordant (seven) scenarios were split at the median and analyzed using the Wilcoxon signed rank sum test.
Overall the agreement between respondents for the clinical scenarios was not acceptable (Kappa=0.28). For the two scenarios where CMa and CCMta guidelines were concordant, specialists had high levels of agreement with recommendations (89% each). A majority of specialists disagreed with CMa recommendations in three of seven discordant scenarios. The lack of consistency in respondents’ agreement attained statistical significance (p<0.001).
Canadian epileptologists have variable counseling practices about driving, and this may be attributable to inconsistencies between CMa and CCMta medical fitness guidelines. This study highlights the need to harmonize driving recommendations in order to prevent physician and patient confusion about driving fitness in Canada.