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Background and ObjectivesPatients with epilepsy have long sought alternatives to conventional antiseizure medications (ASMs) for the treatment of their epilepsy and to improve the significant side effect burden of ASMs and comorbidities. It was established before the legalization of marijuana in Canada in 2018 that many patients with epilepsy use marijuana to treat their seizures or for recreational purposes. However, there exists no current data on the prevalence and habits of marijuana use in the Canadian epilepsy population since legalization.MethodsWe conducted a nationwide cross-sectional survey of patients recruited through health care providers or epilepsy organizations to investigate marijuana usage habits and perceptions.ResultsFrom 395 responses obtained through the survey, 221 responses stated that they used marijuana within the past year. A history of seizures for more than 10 years was noted in 50.7% (n = 148) patients with generalized seizures being the most common type (n = 169; 57.1%). Most of them (n = 154; 52.0%) had tried 3 or more ASMs, and 37.2% (n = 110) used various other treatments (ketogenic diet, vagus nerve stimulation, or resective surgery) indicating a proportion with drug-resistant epilepsy. This subgroup was more likely to have started using marijuana for drug-resistant epilepsy (p< 0.001). Current marijuana use for epilepsy management was endorsed by 47.5% (n = 116). Marijuana was “somewhat” to “very” effective at reducing seizure frequency for 60.1% (n = 123). The main side effects of marijuana were impaired thinking (n = 40; 17.17%), anxiety (n = 37; 15.74%), and altered hunger (n = 36; 15.32%). Marijuana was used at least once daily by 70.3% (n = 168) with the median amount per week being 5.0 g (IQR = 1–10), and the preferred method of consumption was smoking (n = 83; 34.7%). The participants expressed concerns regarding financial strain (n = 108; 36.5%), lack of recommendation from a doctor (n = 89; 30.1%), and lack of information (n = 56; 18.9%) surrounding marijuana use.DiscussionThis study reveals a high prevalence of marijuana use among patients with epilepsy living in Canada particularly when seizures are drug resistant. A significant proportion of patients reported improvement of seizures with marijuana use, consistent with previous studies. With the increased accessibility of marijuana, it is imperative that physicians are aware of marijuana usage habits among patients with epilepsy.

BACKGROUND Both stereoelectroencephalography (SEEG) and subdural strip electrodes (SSE) are used for intracranial electroencephalographic recordings in the invasive investigation of patients with drug-resistant epilepsy. OBJECTIVE To compare SEEG and SSE with respect to feasibility, complications, and outcome in this single-center study. METHODS Patient characteristics, periprocedural parameters, complications, and outcome were acquired from a pro- and retrospectively managed databank to compare SEEG and SSE cases. RESULTS A total of 500 intracranial electroencephalographic monitoring cases in 450 patients were analyzed (145 SEEG and 355 SSE). Both groups were of similar age, gender distribution, and duration of epilepsy. Implantation of each SEEG electrode took 13.9 ± 7.6 min (20 ± 12 min for each SSE; P

Electrical stimulation mapping (ESM) is an important tool for the localization of the seizure onset zone (SOZ) in patients with medically resistant epilepsy (MRE). ESM is the gold standard for the identification of eloquent cortex in epilepsy surgery candidates. However, there is no standard protocol outlining how to perform ESM, to obtain the most useful information possible. The objective of this study, after reviewing the literature concerning ESM, is to propose a unifying technique to validate reliable data across different centers.In this manuscript we summarize this technique from its origin to present, and review protocols used in other centers. We also describe a protocol that has been used in our institution, which utilizes depth electrodes.The most common type of ESM uses a "close-loop" system, bipolar and high frequency stimulation (50 Hz). We propose to use a pulse width of 300 µs, current spanning 1-6 mA in depth electrodes and 1-11 mA in subdural-grids. Stimulation time of 5 s maximum and at least 10 s break in between the stimulations.ESM is a useful tool for understanding eloquent cortex as well as the epilepsy network, although there is no clear consensus regarding how it should be performed.

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.

OBJECTIVE Epilepsy surgery for older adults is controversial owing to their longer duration of epilepsy and perceived higher surgical risk. However, because of an aging population and documented benefit of epilepsy surgery, surgery is considered more frequently for these patients. The authors’ objective was to analyze the role of resective surgery in patients older than 60 years and to assess outcomes and safety. METHODS The authors conducted a retrospective analysis of 595 patients who underwent resective epilepsy surgery at their center from 1999 to 2018. Thirty-one patients aged 60 years or older were identified. Sixty patients younger than 60 years were randomly selected as controls. Population characteristics, results of presurgical evaluations, outcomes, and complications were analyzed. RESULTS No significant differences were found between the groups in terms of hemisphere dominance, side of surgery, presence of a lesion, and incidence of temporal lobe epilepsy. Epilepsy duration was greater in the older cohort (p = 0.019), and invasive EEG was more commonly employed in younger patients (p = 0.030). The rates of Engel class I outcome at 6 months, 1 year, and 2 years were 89.7%, 96.2%, and 94.7% for the older group and 75% (p = 0.159), 67.3% (p = 0.004), and 75.8% (p = 0.130) for the younger group, respectively. The proportion of seizure-free patients was greatest among those with temporal lobe epilepsy, particularly in the older group. Neurological complication rates did not differ significantly between groups, however medical and other minor complications occurred more frequently in the older group. CONCLUSIONS Patients older than 60 years had equal or better outcomes at 1 year after epilepsy surgery than younger patients. A trend toward a greater proportion of patients with lesional temporal lobe epilepsy was found in the older group. These results suggest that good seizure outcomes can be obtained in older patients despite longer duration of epilepsy.

Purpose To provide a descriptive analysis on the presurgical evaluation and surgical management of a cohort of patients with stroke related epilepsy (SRE). Methods We retrospectively examined the clinical characteristics, results of non-invasive and invasive presurgical evaluation, surgical management and outcome of consecutive patients with drug-resistant SRE in our institution from January 1, 2013 to January 1, 2020. Results Twenty-one of 420 patients (5%) who underwent intracranial EEG (iEEG), resective epilepsy surgery and/or vagus nerve stimulation (VNS) placement, had SRE. Of 13 patients who had iEEG, the ictal onset (IO) was exclusively within the stroke lesion in only one patient. In five patients the IO was extra-lesional and in the remaining seven patients it included the stroke lesion as well as extra-lesional structures. The IO included the mesial temporal region in 11 of the 13 patients (85%). The posterior margin of the stroke lesion was always involved. Five patients underwent surgery without iEEG. In total, 10 patients underwent resective surgery, four VNS placement and two had both corpus callosotomy and VNS placement. Of the patients who had resective surgery, nine were Engel I or II at last follow up. Conclusion We found that seizures in patients with drug resistant SRE were more frequently originated in the mesial temporal region than in the stroke lesion itself. Despite the complex epileptic network underlying drug-resistant SRE, a thorough presurgical assessment and adequate use of surgical options can lead to excellent surgical outcomes.

Objective To determine the contribution of stereo-EEG for localization purpose in patients with a visible lesion on MRI. Background Intracranial EEG is often used to localize the epileptogenic focus in patients with non-lesional focal epilepsy. Its role in cases where a lesion is visible on MRI can be even more complex and the relationship between the lesion and the seizure onset has rarely been addressed. Methods All consecutive patients between February 2013 and May 2018 who underwent stereo-EEG and had a lesion visible on MRI were included. We assessed the localization of the seizure onset and its relationship with the lesion. Clinical, radiological, and electrographic analyses were performed. Results Stereo-EEG revealed a seizure onset with either partial or no overlap with the lesion seen on MRI in 42 (56 %) of the 75 lesions included. Mesial temporal sclerosis was the only lesion type associated with an exclusively lesional seizure onset (p = 0.003). Conclusion Epilepsy surgery in MRI-positive cases should rely not only the results of lesions seen on MRI, which might be potentially misleading; SEEG is a gold standard method in these cases to define resective borders.

Objective To determine if the ictal onset recorded with stereoelectroencephalography (SEEG) during clusters of seizures is reliable to identify the laterality of the epileptogenic zone. Background In the presurgical evaluation of patients with focal drug-resistant epilepsy, the presence of bilateral ictal onset is usually associated with a poor surgical outcome. It has been reported that the laterality of seizures can be influenced during seizure clusters, although this remains controversial. Most studies have addressed this issue using scalp EEG which could erroneously determine the laterality of the ictal onset. Methods We examined all consecutive patients who underwent SEEG with bilateral hemispheric coverage at our institution between January 2013 and September 2018. We assessed the presence of seizure clusters (clinical or subclinical), their laterality by SEEG and the surgical outcome of the patients. A descriptive clinical and electrographic analysis was performed. Results Of 143 patients who underwent SEEG recordings, we identified only six patients who had bilateral ictal onset that went on to resective surgery. In all six patients the discordant seizures occurred during a seizure cluster. Three of these patients were seizure free at last follow up. Conclusion Discordant seizures obtained during a seizure cluster may not necessarily mean that the patient has bilateral epilepsy, and therefore a poor post-surgical outcome. Seizure clusters may not reliably lateralize the epileptogenic zone.

Objective To evaluate the efficacy and tolerability of adjunctive brivaracetam (BRV) in adults with focal seizures by the number of lifetime (previous and concomitant) antiepileptic drugs (AEDs). Methods Post-hoc analysis of data from N01358 (NCT01261325), a randomized, double-blind, placebo (PBO)-controlled Phase III trial evaluating BRV 100 and 200 mg/day in patients ≥16 years of age with uncontrolled focal seizures. Efficacy and tolerability outcomes were assessed for the 12-week Treatment Period in subgroups of patients with 1–2, 3–4, 5–6, or ≥7 lifetime AEDs. Results 764 patients received at least one dose of trial medication (BRV: 503; PBO: 261; Safety Set), of whom 14.3% had 1–2, 20.8% had 3–4, 21.3% had 5–6, and 43.6% had ≥7 lifetime AEDs. In all lifetime AED subgroups, >85% of patients completed the trial. Patients with a higher number of lifetime AEDs had a younger age at epilepsy onset, longer epilepsy duration, and higher baseline seizure frequency. In patients on BRV, 50% responder rates were 49.3%, 44.4%, 47.2% and 27.4% in patients with 1–2 (n = 75), 3–4 (n = 99), 5–6 (n = 108) and ≥7 (n = 219) lifetime AEDs; 75% responder rates were 36.0%, 21.2%, 22.2% and 12.3%. In patients on PBO, 50% responder rates were 35.3%, 25.9%, 20.4% and 15.9% in patients with 1–2 (n = 34), 3–4 (n = 58), 5–6 (n = 54) and ≥7 (n = 113) lifetime AEDs; 75% responder rates were 26.5%, 6.9%, 3.7% and 4.4%. The Kaplan-Meier estimated probability of patients achieving a sustained 50% or 75% response from the first day of treatment was generally higher in patients with a lower number of lifetime AEDs (both in patients on BRV and PBO). In patients on adjunctive BRV, the incidence of drug related treatment-emergent adverse events (TEAEs) was 34.7%, 26.0%, 44.4% and 47.7% in patients with 1–2 (n = 75), 3–4 (n = 100), 5–6 (n = 108) and ≥7 (n = 220) lifetime AEDs; the incidence of discontinuations due to TEAEs was 1.3%, 3.0%, 8.3% and 10.5%. Conclusions This post-hoc analysis suggests a numerically higher response to adjunctive BRV in patients with fewer lifetime AEDs. The lowest response was observed in patients with ≥7 lifetime AEDs, although these patients could also benefit from adjunctive BRV treatment. Patients with fewer lifetime AEDs had lower discontinuation of BRV due to TEAEs.

BACKGROUND: For patients with generalized epilepsy who do not respond to antiseizure medications, the therapeutic options are limited. Vagus nerve stimulation (VNS) is a treatment mainly approved for therapy-resistant focal epilepsy. There is limited information on the use of VNS on generalized epilepsies, including Lennox-Gastaut Syndrome (LGS) and genetic generalized epilepsy (GGE). METHODS: We identified patients with a diagnosis of generalized epilepsy (including LGS and GGE), who underwent VNS implantation at the London Health Sciences Centre and Western University, London, Ontario, since this treatment became available in Canada in 1997 until July 2018. We assessed response to the treatment, including admissions to hospital and complications. RESULTS: A total of 46 patients were included in this study with a history of therapy-resistant generalized epilepsy. The mean age at implantation was 24 years (interquartile range [IQR] = 17.8-31 years), significantly younger in the LGS group (p = 0.02) and 50% (n = 23) were female. The most common etiologies were GGE in 37% (n = 17) and LGS in 63% (n = 29). Median follow-up since VNS implantation was 63 months (IQR: 31-112.8 months). Of the LGS group 41.7% (n = 12) of patients had an overall seizure reduction of 50% or more, and 64.7% (n = 11) in the GGE group without statistical significance between the groups. The best response in seizure reduction was seen in generalized tonic-clonic seizures, with a significant reduction in the GGE group (p = 0.043). There was a reduction of seizure-related hospital admissions from 91.3% (N = 42) preimplantation, to 43.5% (N = 20) postimplantation (p

Background:“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.Objective:We present a small case series of temporal plus cases successfully identified by SEEG who were seizure-free after resective surgery.Methods: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.Results: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.Conclusion: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.

This study was aimed to longitudinally assess memory function and whole-brain memory circuit reorganization in patients with temporal lobe epilepsy (TLE) by comparing activation potentials before versus after anterior temporal lobe (ATL) resection. Nineteen patients with medically-intractable TLE (10 left TLE, 9 right TLE) and 15 healthy controls were enrolled. Group analyses were conducted pre- and post-ATL of a novelty complex scene-encoding paradigm comparing areas of blood oxygen-level-dependent (BOLD) signal activations on functional magnetic resonance imaging (fMRI). None of the pre-operative patient characteristics we studied predicted the extent of pre- to post-operative memory loss. On fMRI, extra-temporal activations were detected pre-operatively in both LTLE and RTLE, particularly in the frontal lobe. Greater activations also were noted in the contralateral hippocampus and parahippocampus in both groups. Performing within-subject comparisons, post-op relative to pre-op, pronounced ipsilateral activations were identified in the left parahippocampal gyrus in LTLE, versus the right middle temporal gyrus in RTLE patients. Memory function was impaired pre-operatively but declined after ATL resection in both RTLE and LTLE patients. Post-operative fMRI results indicate possible functional adaptations to ATL loss, primarily occurring within the left parahippocampal gyrus versus right middle temporal gyrus in LTLE versus RTLE patients, respectively.

Septo-optic dysplasia (SOD) is a rare disorder associated with optic nerve hypoplasia, pituitary abnormalities and agenesis/dysgenesis of midline brain structures including the septum pellucidum and corpus callosum. Though sometimes associated with drug-resistant epilepsy, this association has not been well studied. We report six SOD patients with associated malformation of cortical development (MCD) and drug-resistant epilepsy who underwent video-EEG telemetry at our centre between 1998 and 2016 for drug-resistant epilepsy. ‬Three then underwent surgery; right temporal neocortical resection, right functional hemispherectomy and placement of a vagus nerve stimulator. Clinical findings and the patients' ultimate courses are discussed.

Idiopathic generalized epilepsy (IGE) is an epileptic condition with good response to antiepileptic drugs (AED). Major syndromes are epilepsy with generalized tonic-clonic seizures (GTCS) alone, absence epilepsy and juvenile myoclonic epilepsy. However, clinical practice shows drug-resistant patients. Endpoint is to identify clinical features related with refractoriness in IGE and in its each individual syndrome.We retrospectively collected 279 consecutive patients with IGE assessed in the Epilepsy Clinic of our institution. We defined drug-resistant epilepsy as a failure of adequate trials of 2 tolerated and appropriately chosen and used AED schedules. We classified patients in two groups: drug-resistant and drug-responsive. Clinical features were compared among these groups, in the whole IGE group as well as in each syndrome.There were 122 drug-resistant, 105 drug- responsive; 52 were undefined and excluded from the analysis. After multivariate analysis, early seizures onset (age13), long-time epilepsy, several generalized seizure types, status epilepticus, EEG with generalized epileptiform activity, mainly polyspikes, and side effects with AED brought up as poor outcome factors. Additionally, 50.6% identified modifiable seizure triggers. Regarding syndromes, epilepsy with generalized tonic-clonic seizures alone had the same factors except several seizure types; presence of additional GTCS, polyspikes, history of AED side effects and psychiatric disorder were poor factors for absence epilepsy; only psychiatric comorbidity revealed significance in juvenile myoclonic epilepsy.Refractoriness in IGE and its major syndromes is associated with clinical and electrographic parameters. Moreover, lifestyle advices from neurologists to the patients might help them to achieve a better seizure control.

Objective We present a single-center retrospective study of benign mesial temporal lobe epilepsy (bMTLE) between 1995 and 2014. Methods Hospital records and clinic charts were reviewed. The clinical, Eelectroencephalographic (EEG), imaging features, and response to treatment with antiepileptic drugs (AEDs) were documented. Patients were included in this study if they were seizure-free for a minimum of 24 months with or without an AED. Results Twenty-seven patients were identified. There were 19 (70%) females, mean age at first seizure was 32.2 (range: 15–80 years). In all patients, seizures were mild, and seizure freedom was readily achieved with the initiation of AED therapy. Sixteen patients (59%) had mesial temporal sclerosis (MTS). In three patients, we attempted to discontinue AED therapy after a prolonged period of remission (5–8 years), but all had seizure recurrence within 2 to 4 weeks. Significance Not all temporal lobe epilepsy is refractory to medication, despite the presence of MTS. Until clinical trials indicate otherwise, surgery is not indicated but life-long medical treatment is advocated.

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.

We provide an overview of the surgical outcome of extra-hypothalamic epilepsies with gelastic seizures based on an original case report and a summary of the literature. Twenty-two articles providing information on the outcome of resective surgery in 39 patients with extra-hypothalamic gelastic seizures from the temporal (19 patients) or frontal lobe (20 patients) were selected. We add another case of temporal lobe gelastic seizures to the literature with a video demonstrating the mirthful component of this patient's laughing seizures. Drug-refractory cases of gelastic seizures from the temporal or frontal lobes are amenable to surgical treatment following thorough investigation with imaging, as well as scalp and intracranial EEG.

Objective Vagus Nerve Stimulation (VNS) is a neuromodulation device approved for the treatment of medically refractory epilepsy. Worldwide, only 35 cases of pregnancies that has been described. This study aims to continue to increase the limited knowledge of the use of VNS during pregnancy. Methods We interrogated the database of the Epilepsy program at Western University (1998–2018), and identified those patients who were implanted with VNS and became pregnant. Results From 114 patients implanted with VNS in our centre, four patients had a total of seven pregnancies. This is the first report with one woman implanted with VNS having three pregnancies. Three patients had genetic generalized epilepsy and one focal epilepsy due to periventricular nodular heterotopia. The median duration since implantation was 3.17 years (IQR: 1.33–4.33) and the output was 2.75 mA (IQR: 1.5–3.5). No modifications in stimulation settings were made in any patient during pregnancy. Three patients had obstetric complications, requiring c-sections. All babies were healthy, except one with intellectual disabilities of unclear severity. Conclusion Our small sample suggests VNS could increase the obstetrical complications, but is likely safe for the fetus. However, a larger sample size should be collected to determine safety and potential teratogenicity of VNS.

Background Temporal lobe epilepsy (TLE) with unclear lateralization may require intracranial implantation of electrodes (IIE). We retrospectively assessed the association between the use of IIE and long-term outcomes in patients undergoing anterior temporal lobectomy (ATL). Participants and methods We retrospectively reviewed the records of 1,032 patients undergoing epilepsy surgery at our center from 1977 to 2006. Patients who underwent ATL were included. Seizure outcome was assessed through final follow-up. Those who underwent scalp and IIE (mostly evaluated with temporal subdural strip electrodes) were compared. Results From 497 patients who underwent ATL, 139 did so after IIE placement in the temporal lobes. Mean age at surgery was 32.3±12.3years and median duration of follow-up 24 months (range: 6–36). Fifty-three percent of those evaluated with IIE were seizure-free at their last available visit (vs. 68% evaluated with only scalp EEG, p=0.002). Patients with lesional TLE generally had a better outcome (65.5% seizure free) than those without lesions (56.3%, p=0.093), especially for unilateral TLE diagnosed with IIE. In a multivariate Cox regression analyses adjusted for gender, neuropsychological concordance, pathological findings, and post-operative seizures, bilateral TLE predicted seizure recurrence in IIE patients (HR=2.08, 95% CI: 1.08–4.0, p=0.029). Conclusions More than a half of those who undergo IIE in suspected TLE are seizure free after ATL. IIE allows for the identification of surgical candidates.

Epidemiologic evidence supporting antiseizure properties of cannabis is limited and controversial. We determined the prevalence of marijuana use and its perceived effects in patients with and without epilepsy.Information was collected over 14months from consecutive adult patients admitted to an epilepsy monitoring unit using a 27-item anonymous questionnaire. Patients with cognitive impairment unable to understand the questions or give informed consent and readmissions were not recruited. Subjects were divided into 4 groups, those with epileptic seizures, those with psychogenic nonepileptic seizures (PNES), those with both epileptic and PNES, and those with other nonepileptic events. Patients with exclusively epileptic seizures were compared with those with exclusively PNES.From 310 patients, 18 undiagnosed cases were excluded leaving a cohort of 292 patients with median age 35 (range: 27-49) years; 57.2% female. Epilepsy was documented in 190 (65.1%), PNES in 64 (21.9%), and both types of seizures in 26 (8.9%). Median duration of seizure disorder was longer (2 [1-9] vs. 13 [5.7-25] years; p0.001) and seizure frequency lower (daily or weekly in 62.3% vs. 44.9%; p=0.03) in patients with epilepsy compared with those in patients with PNES. Overall, 166 (57%) had tried marijuana, and 36.2% used it over the past year. Utilization was 57.1% in sole epilepsy and 64.1% in sole PNES, but daily use was more likely in epilepsy (59% vs. 33.3%). Estimated mean dose was 1g/day. Marijuana use was associated with tobacco smoking (p0.001) but not alcohol use. Eight patients used other street drugs. Improvement in seizures was perceived by 84% in those with epilepsy and 72.7% in those with PNES. In the 2 groups, stress was decreased in 84.9% and 88%, sleep improved in 77.3% and 88%, and memory/concentration was better in 32% and 28%, respectively. Antiepileptic drug side effects were decreased in 53.2% of marijuana users. Perceived effect on epileptic seizures correlated with effect on stress (r=0.35, p=0.004). Adverse effects of marijuana were mild and reported in 30.7% but included possible seizure precipitation in 5 patients with epilepsy.Patients with uncontrolled epilepsy or nonepileptic events had a high rate of marijuana use with associated perceived improvements in seizure control, stress, sleep, and drug side effects. Stress reduction may contribute to the perceived impact of marijuana on seizures and nonepileptic events in adults.

The biology of the endocannabinoid system in the brain provides a possible basis for a beneficial pharmacological effect of marijuana on seizures. However, evidence for efficacy of cannabis treatment of epilepsy is anecdotal because no acceptable randomized controlled trials have been done. Proper dosage and means of administration remain unknown. Cannabis is safer than other controlled substances, including tobacco or alcohol, and appears to be relatively safe compared with most pharmaceuticals used to treat epilepsy. This is a review of this topic from a Canadian perspective.

Background Orbitofrontal epilepsy (OFE) is less known and is poorly characterized in comparison with temporal lobe epilepsy, partly because it is rare and possibly because it is unrecognized and therefore underestimated. Objective This paper aimed to better characterize seizure semiology, presurgical findings, and surgical outcomes in patients with OFE. Methods We retrospectively reviewed all confidently established OFE cases from six Canadian epilepsy monitoring units between 1988 and 2014, and in the literature between 1972 and 2017. Inclusion criteria were identification of an epileptogenic lesion localized in the OFC or if the patient was seizure-free after surgical removal of the OFC in nonlesional cases. Results Sixteen cases were identified from our databases. Fifty percent had predominantly sleep-related seizures; 56% had no aura (the remaining had nonspecific or vegetative auras), and 62.5% featured hypermotor (mostly hyperkinetic) behaviors. Interictal epileptiform discharges over frontal and temporal derivations always allowed lateralization. Magnetic resonance imaging (MRI) identified an orbitofrontal lesion in 8/16, positron emission tomography (PET) identified a hypometabolism extending outside the orbital cortex in 4/9, ictal single-photon emission computed tomography (SPECT) identified an orbital hyperperfusion in 1/5, magnetoencephalography (MEG) identified lateral orbital sources in 2/4, and intracranial electroencephalography (EEG) identified an orbitofrontal onset in 9/10. Fourteen patients underwent surgery, all reaching a favorable outcome (71.4% Engel 1; 28.6% Engel 2; mean FU = 5.6 years). Pre- and postoperative neuropsychological assessments revealed heterogeneous findings. Our review of literature identified 71 possible cases of OFE, 32 with confident focus localization. Extracted data from these cumulated cases supported observations made from our case series. Conclusions Orbitofrontal epilepsy should be suspected with sleep-related, hyperkinetic seizures with no specific aura, and frontotemporal interictal discharges. Several patients have nonmotor seizures with or without auras which may resemble temporal lobe seizures. Postoperative seizure outcome was favorable, but there is inherent bias as we only included patients with a seizure-free outcome if the MRI was negative. A larger study is required to address identified gaps in knowledge such as identifying discriminative features between medial and lateral OFE, evaluating the value of more recent diagnostic tools, and assessing the neuropsychological outcome of orbital epilepsy surgery.

SummaryObjective To examine the 30-day risk of hospitalization with hyponatremia associated with carbamazepine, valproic acid (V), phenytoin (P), or topiramate (T) use compared to nonuse in the outpatient setting among older adults. Methods We conducted two population-based, retrospective cohort studies in Ontario, Canada, between 2003 and 2015 using administrative health care databases of older adults. The first study compared carbamazepine users to a propensity-score matched group of antiepileptic drug nonusers, whereas the second compared V-P-T users to a propensity-score matched group of antiepileptic nonusers. The primary outcome was hospitalization with hyponatremia within 30 days of an antiepileptic prescription. Results The baseline characteristics between matched groups were similar in both cohorts. Carbamazepine use versus nonuse was associated with a higher 30-day risk of hospitalization with hyponatremia (82/21,191 [0.39%] versus 30/63,573 [0.05%]; relative risk [RR] 8.20, 95% confidence interval [CI] 5.40–12.46). Similarly, V-P-T use versus nonuse was associated with a higher 30-day risk of hospitalization with hyponatremia (34/20,155 [0.17%] versus 26/40,310 [0.06%]; RR 2.62, 95% CI 1.57–4.36). Significance Older adults prescribed carbamazepine and V-P-T have a higher risk of being hospitalized with hyponatremia compared to other adults with similar indicators of baseline health who were not prescribed antiepileptic drugs. Physicians should be mindful of this risk; when a patient presents to a hospital with symptomatic hyponatremia these drugs should be considered as potential causes.

Objective The aim of this study was to investigate the lateralizing and localizing value of ictal coprolalia and brain areas involved in its production. Methods A retrospective search for patients manifesting ictal coprolalia was conducted in our EMU database. Continuous video-EEG recordings were reviewed, and EEG activity before and during coprolalia was analyzed using independent component analysis (ICA) technique and was compared to the seizures without coprolalia among the same patients. Results Nine patients were evaluated (five women), eight with intracranial video-EEG recordings (icVEEG). Four had frontal or temporal lesions, and five had normal MRIs. Six patients showed impairment in the language functions and five in the frontal executive tasks. Two hundred six seizures were reviewed (60.7% from icVEEG). Ictal coprolalia occurred in 46.6% of them, always associated with limbic auras or automatisms. They arose from the nondominant hemisphere in five patients, dominant hemisphere in three, and independently from the right and left hippocampus–parahippocampus in one. Electroencephalographic activity always involved orbitofrontal and/or mesial temporal regions of the nondominant hemisphere when coprolalia occurred. Independent component analysis of 31 seizures in seven patients showed a higher number of independent components in the nondominant hippocampus–parahippocampus before and during coprolalia and in the dominant lateral temporal region in those seizures without coprolalia (p = 0.009). Five patients underwent surgery, and all five had an ILAE class 1 outcome. Significance Ictal coprolalia occurs in both males and females with temporal or orbitofrontal epilepsy and has a limited lateralizing value to the nondominant hemisphere but can be triggered by seizures from either hemisphere. It involves activation of the paralimbic temporal–orbitofrontal network.

Routine EEG telemetry using scalp electrode recordings is carried out in all patients being considered for epilepsy surgery. However this, along with other testing, may not yield sufficient information about the location of seizure onset to allow a decision regarding surgery to be made. Various methods have been developed to implant electrodes for chronic recording closer to the cortical surface from which seizures arise including the use of sphenoidal, foramen ovale, epidural peg, subdural and depth electrodes. This is a review of the last two techniques particularly as utilized at London Health Sciences Centre.

Introduction Epilepsy arising from the insula is widely regarded as a challenging type of seizure, probably owing to the deep-seated location of the insula and the extensive connections it makes with adjacent structures. In recent years, we have rapidly gained insights into insular epilepsy-related obstacles. Here, we describe a detailed analysis of the electro-clinical manifestations of this type of epilepsy using intra-cerebral recordings performed with Stereo-electroencephalography (SEEG). Methods We retrospectively analyzed 12 patients from our epilepsy program who underwent insular exploration using SEEG between June 2013 and June 2017. Patient information reviewed included demographics, clinical history, neurological examination; neuroimaging studies (Brain MRI, PET, Ictal SPECT), Scalp video-EEG, intracranial recordings with SEEG, histopathological findings, and surgical outcomes. Results 12 patients (M:F = 4:8; mean age, 32.5 years; range, 19–60 years) were found with seizures originating from either the insula alone or simultaneously originating from the insula and adjacent structures. One patient had a family history of epilepsy and another one had previous exposure to viral meningoencephalitis. Six patients had undergone prior surgery for epilepsy treatment. The mean seizure frequency was 4 seizures per week, and one patient experienced seizures daily. The most common aura was somatosensory sensation, followed by cephalic sensation in 4 and 3 patients, respectively. The commonest type of seizure was focal with impaired awareness in 10 patients. 50% of the patients showed a tendency for secondary generalizations, and 25% showed nocturnal predominance. Lesions were observed on brain MRI in 8 cases. Scalp EEG revealed different interictal discharge distributions: 5 patients showed localized frontotemporal spikes, 3 showed bilateral temporal spikes, and no spikes were detected in 4. The location of ictal onset could be localized in only 50% of patients. The most common scalp EEG ictal pattern was rhythmic delta activity (1–3 Hz). Subsequent SEEG showed six patients found to have a combination of clinical and subclinical seizures. SEEG clinical seizure onset from the insula alone was found in 50% of the patients (3 right, 2 left, 1 bilateral). The other patients presented with simultaneous onset from the insula and adjacent structures: 4 from mesial temporal structures, 1 temporal operculum, and 1 frontal operculum. The commonest SEEG ictal pattern was low voltage fast activity in 8 patients. Surgical resections guided by SEEG findings were performed in 5 patients and led to excellent outcomes; all these cases had Engle class 1 outcome at 6–24 months follow up. Conclusion We observed that it is not uncommon for seizures to simultaneously originate from the insula and adjacent structures. However, non-invasive EEG monitoring tools are likely insufficient to detect such simultaneous seizures. For the given sample, SEEG proved beneficial in providing optimal surgical outcomes.

The effect of continuous electrical stimulation of the hippocampus bilaterally on seizures and memory was assessed in two subjects with seizures from both mesial temporal lobes who were not candidates for resective epilepsy surgery. A double blind, randomized, controlled, cross-over trial design was utilized. Two electrodes with four contacts each were implanted along the axis of the hippocampus bilaterally. Simultaneous stimulation of all electrodes contacts was either on or off during each 3-month interval. Seizure frequency decreased by 33% in the two patients during stimulation and remained lower by 25% for the 3 months after stimulation was turned off before returning to baseline (p < 0.01). No consistent change in objective or subjective measures of memory occurred. No other adverse effects occurred. Seizure frequency is reduced both during and for a period after bilateral hippocampal stimulation, but the overall impact in this study is not as robust as has been previously reported.

Invasive intracranial electrodes (IE) are an important part of the work-up in many patients being considered for epilepsy surgery. Because IE are usually reserved for cases where seizure localization is ambiguous, one might expect that the eventual outcome of epilepsy surgery in these patients would be worse than in patients who did not require IE as part of their work-up. The purpose of this study was to specifically examine those patients who underwent insertion of subdural electrodes, to determine how many of these patients eventually underwent resective surgery of any type and to assess the eventual outcome. All cases admitted for subdural electrodes between January 2000 and June 2005 were reviewed. Surgical outcomes were reported using the Engel classification and a multivariate analysis was used to determine which factors were associated with successful surgery. 177 IE implantations were performed in 172 patients. Of these, 130 patients went on to have surgery. In the 113 of the 130 surgical patients in whom 1-year follow-up was available, 47% were seizure free at 1 year. Age was a major predictor of outcome with only 21% of patients over age 40 becoming seizure free with surgery compared to 58% in patients aged under 40 years (p=0.0004). Other predictors of an Engel I outcome included having a temporal lobectomy or supplementary motor area resection. Good results from eventual resective surgery can be achieved in patients needing invasive recordings. Younger patients with temporal lobe epilepsy seem to have the highest likelihood of seizure freedom.

✓ Temporal lobe epilepsy (TLE) is the most common type of surgically treatable epilepsy, with a considerable number of patients needing invasive electroencephalography monitoring. The authors describe a surgical technique used in the placement of subdural strip electrodes for coverage of the temporal lobe. The electrodes are inserted through an enlarged temporooccipital bur hole using fluoroscopic guidance. With this technique, subdural electrode strips can be safely placed to cover the mesial, inferior, and lateral temporal surfaces, and the seizure focus can be lateralized and localized within the temporal lobe. The technique does not require the use of a craniotomy, stereotactic frame, or neuronavigation systems. The authors compare this technique with previous descriptions of subdural electrode placement for the evaluation of TLE.

BACKGROUND: In some jurisdictions, physicians are required by law to report patients with seizures to the department of motor vehicles. We assessed the hypothesis that mandatory reporting reduces the risk of automobile accidents in people with epilepsy. METHODS: A retrospective survey of driving and accident rates was done by mailed questionnaire to two groups of subjects with epilepsy in Canada, one living in Ontario where reporting is mandatory and the other in Alberta where it is not. Responses were obtained from a control group without epilepsy for comparison. RESULTS: The epilepsy (n = 425) and control (n = 375) groups were comparable in age and sex. Seventy-three percent of the epilepsy group were or had been licensed drivers compared to 94% of the controls (rr 0.77, 95% CI 0.73-0.83, p Language: en

Background: Adjustable, reversible therapies are needed for patients with pharmacoresistant epilepsy. Electrical stimulation of the hippocampus has been proposed as a possible treatment for mesial temporal lobe epilepsy (MTLE). Methods: Four patients with refractory MTLE whose risk to memory contraindicated temporal lobe resection underwent implantation of a chronic stimulating depth electrode along the axis of the left hippocampus. The authors used continuous, subthreshold electrical stimulation (90 μsec, 190 Hz) and a double blind, multiple cross-over, randomized controlled design, consisting of three treatment pairs, each containing two 1-month treatment periods. During each treatment pair the stimulator was randomly turned ON 1 month and OFF 1 month. Outcomes were assessed at monthly intervals in a double blind manner, using standardized instruments and accounting for a washout period. The authors compared outcomes between ON, OFF, and baseline periods. Results: Hippocampal stimulation produced a median reduction in seizures of 15%. All but one patient’s seizures improved; however, the results did not reach significance. Effects seemed to carry over into the OFF period, and an implantation effect cannot be ruled out. The authors found no significant differences in other outcomes. There were no adverse effects. One patient has been treated for 4 years and continues to experience substantial long-term seizure improvement. Conclusion: The authors demonstrate important beneficial trends, some long-term benefits, and absence of adverse effects of hippocampal electrical stimulation in mesial temporal lobe epilepsy. However, the effect sizes observed were smaller than those reported in non-randomized, unblinded studies.

Objective: To determine the accuracy of the clinical history performed by epileptologists in the identification of seizures in patients with suspected temporal lobe epilepsy. Methods: The clinical and EEG telemetry (EEGT) monitoring data of 88 patients with suspected refractory temporal lobe seizures referred for evaluation of epilepsy surgery were prospectively evaluated. All clinical events obtained by history in these patients were adjudicated as being a seizure or not by two blinded (without access to EEG data) independent epileptologists. Each clinical event was then matched with the corresponding clinical event recorded with EEG telemetry in the epilepsy monitoring unit (gold standard). Sensitivity, specificity, overall accuracy, predictive value, and interrater agreement for the clinical assessment were obtained. Results: Of 357 clinically different events, 175 (49%) were reproduced in the epilepsy monitoring unit. Only 10 events were misidentified by history as being a seizure or not, resulting in an overall clinical accuracy of 94%. Epileptologists’ sensitivity for seizure identification was 96% (95% CI 92, 98%) but specificity was only 50% (95% CI 22, 79%). Accuracy for complex partial seizures and generalized seizures was higher than for simple partial seizures (SPS). Misidentification occurred only with SPS and nonepileptic events. Agreement beyond chance among epileptologists was good. Conclusion: In this selected group of patients with temporal lobe epilepsy, seizure identification by clinical history is highly accurate. Epileptologists rarely miss seizures (high sensitivity) but more often overcall nonepileptic events as seizures (low specificity).

We assessed the impact of vagus nerve stimulation on a cohort of patients with intractable epilepsy. A 1-year prospective trial of vagus nerve stimulation for intractable epilepsy was done in 26 patients. Seizure frequency, anti-epileptic drugs, and quality of life were assessed using QOLIE-89, ELDQOL, and a Likert scale of impact of treatment. Seizures were reduced by more than 50% in 19% of the patients, by less than 50% in 46%, and were unchanged in 35% of them. Antiepileptic drugs were reduced in 43% of the patients. There was a significant improvement in the mean overall QOLIE-89 score and other measures of quality of life, but these did not correlate with changes in seizure frequency. Subjective improvement occurred in 84% of the patients. The quality of life improves in some patients following vagus nerve stimulation for intractable epilepsy. The favorable effects of this treatment may be attributable to additional factors besides seizure control which in this study was modest.

Background:Six/second spike waves, 14 and 6/second positive spikes and small sharp spikes are apiculate paroxysmal rhythms in the electroencephalogram, thought to be of no diagnostic importance. The cortical origin of these discharges is documented in this report.Methods:These waveforms were assessed in recordings from the surface of the cerebral cortex using implanted subdural electrodes in 61 patients monitored for possible epilepsy surgery.Results:Eight patients had 6/second spike wave, four had 14 and 6/second positive spikes and 3 had small sharp spikes. The 6/second spike waves were localised to the posterior cingulate gyrus, a more restricted region than would be predicted from scalp recordings and the 14 and 6/second spikes to the posterior mesial temporal cortex. Small sharp spikes were more widely distributed but also predominated in the posterior mesial temporal area. None of the discharges were congruent with the focus of seizure origin and no interaction with other interictal spikes was found.Conclusions:These benign paroxysmal rhythms can appear incidentally in the electrocorticograms of patients with focal epilepsy and should not be confused with focal pathological spike activity or considered to be of any value in localizing the seizure focus.

This study investigated whether the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) items reflecting seizure symptoms spuriously inflate MMPI-2 scores in persons with epilepsy. In a repeated measures prospective design, patients with epilepsy completed the MMPI-2 prior to epilepsy surgery and again two years later when they were either seizure-free or not seizure-free. Compared to baseline scores, only seizure-free patients showed a decline in endorsement of seizure items, and only on one scale, Hypochondriasis (Hs). Clinical profiles were not meaningfully different when readministered when seizures were no longer present. Moreover, profiles generated by individuals with and without seizures were not significantly different. We conclude the MMPI-2 is a valid test in an epilepsy population, as seizure content did not alter its clinical interpretation. In using the MMPI-2 in patients with epilepsy, a modest correction on the Hs and Schizophrenia (Sc) scales is warranted in selected cases. In MMPI-2 research, assessing both statistical and clinical significance is recommended.

There are between 20 and 30 drugs available for the treatment of seizures but despite this ~30% of the epilepsy population remains unresponsive to treatment. The underlying mechanisms behind drug resistance in temporal lobe epilepsy (TLE) have not been completely identified. The purpose of this study was to determine if distinct types of neuronal firing patterns occurring in human epileptic cortex are altered by carbamazepine (CBZ). We used whole-cell patch-clamp techniques combined with intracellular labeling to electrophysiologically and morphologically characterize neuronal populations in resected cortical tissue from patients with drug resistant epilepsy. We then determined if cells were uniformly resistant to carbamazepine or whether only a subset did not respond. Cortical spiking patterns were segregated in six main clusters: adapting high frequency cluster 1 and 2 (AHF1 and AHF2), adapting low frequency cluster 1 and 2 (ALF1 and ALF2), strongly adapting low frequency group (sALF) and one spike cluster (OS). A morphological analysis showed that some spiking patterns tend to be associated with specific neuronal morphology. OS group included only pyramidal cells while adapting high frequency groups (AHF1 &AHF2) displayed typical interneuron phenotype. Finally, we found that CBZ does not uniformly suppress neuronal activity as only ~27% of interneurons and ~40% of pyramidal cells were carbamazepine insensitive. These data indicate that in humans with DRE there is a heterogeneous CBZ insensitivity in all sub-populations of neurons.

Background: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.Objectives: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.Methods: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.Results: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 (pConclusions: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.

Purpose:To describe a delayed severe complication of temporal lobectomy for intractable epilepsy.Method:A case of amnesia occurring 24 years after surgery is described and five similar cases from the literature reviewed.Results:Mean age at surgery (5 right) was 40 years (19-62 years), 3 female. Four of five tested had impaired visual and verbal memory preoperatively but not sufficient to contraindicate surgery. Pathology was mesial temporal sclerosis in 3, 1 cavernoma, 1 dysembryoplastic neuroepithelial tumor (DNET) and 1 normal. Postoperatively, four were seizure free 3-12 years off medication and two continued with seizures. There was no unexpected postoperative memory change until incapacitating anterograde amnesia developed 1-24 years after surgery. In five patients, including ours, this followed definite or possible status epilepticus with new mesial temporal sclerosis on the opposite side in the four that were investigated by MRI. One patient developed a glioblastoma in the opposite temporal lobe.Conclusion:Continuing or late recurrence of seizures from the remaining temporal lobe after temporal lobectomy can result in incapacitating amnesia if status epilepticus occurs. Other new lesions on the opposite side to surgery can have the same effect.

Subjective memory (SM), a self-evaluation of memory, in contrast to objective memory (OM) measured by neuropsychological testing, is less well studied in patients with epilepsy. We assessed SM before and after temporal lobectomy. The Frequency of Forgetting 10 scale (FOF-10), developed to evaluate SM in dementia, was given before and one year after temporal lobectomy. Reliability and validity for use in epilepsy were first assessed. Measures of depression (CES-D) and neuroticism (PANAS) were done before and after surgery as well as complete neuropsychological assessment of OM. Correlation analysis between FOF-10 results and all the other variables was implemented. In 48 patients the FOF-10 was reliable and valid showing high internal consistency in all items (Cronbach's alpha >0.82) and high reproducibility (p

Summary Purpose: The intracarotid amobarbital procedure (LAP) is widely used to help predict who might be at risk for postoperative amnesia after unilateral temporal lobectomy for intractable seizures. We describe the memory outcome in 10 patients who underwent standard temporal lobectomy, including mesial temporal structures, despite failing the memory portion of the LAP after injections both ipsilateral and contralateral to the resected seizure focus. Methods: Data for seven of the study subjects were obtained through a retrospective review of patients assessed on a surgical epilepsy unit during a 15-year period who failed the Montreal Neurological Institute LAP memory protocol after both ipsilateral and contralateral injections and subsequently underwent unilateral temporal lobectomy. More recently, we have studied temporal lobectomy patients who failed the Medical College of Georgia memory protocol after both ipsilateral and contralateral injections (n = 3). Preoperative and postoperative memory test scores were compared, and data regarding seizure outcome and self-perception of postoperative memory were collected. Results: At follow-up, none of the patients presented with a pattern indicative of a global amnesia, and 80% demonstrated >90% improvement in their seizure disorder or were seizure-free. Conclusions: These findings indicate that bilateral memory failure on the LAP does not preclude the removal of an epileptogenic temporal lobe or a successful surgical outcome. In addition, the findings raise questions regarding the validity of the LAP and the possibility that memory may be reorganized in patients with a long history of temporal lobe epilepsy.

The management of uncontrolled partial epilepsy is a process dependent on a multidisciplinary and analytic approach. It is necessary to understand which lesions are epileptogenic, and if they are indeed responsible for the generation of seizures. In addition to localizing seizure onset, the functional and eloquent areas of the brain need to be identified. As in many other centres, we perform resective surgeries on the basis of combined information derived from seizure semiology, EEG abnormalities, neuroimaging and other tests of cerebral function. If surface EEG recording yields inconclusive or ambiguous results, then invasive intracranial techniques using intracerebral depth or subdural electrodes can be used to improve diagnostic or prognostic accuracy. The indications, principles, results and complications of these recording techniques based on extensive experience at two epilepsy surgery centres are reviewed.

The favourable impact of surgery for intractable epilepsy on seizures is well documented. However, few studies have determined what changes in antiepileptic drug (AED) therapy occur following surgery. Alterations in AED blood levels in the immediate postoperative period can result in breakthrough seizures. In long term follow-up, one-third to one-half of seizure-free patients after temporal lobectomy, the most common type of epilepsy surgery, still require AED treatment which usually has been reduced from polytherapy to monotherapy. In our study of 93 patients followed two years after temporal lobectomy, polytherapy decreased from 78% before surgery to 14% postoperatively, while medication was discontinued in 44%. Early reduction from polytherapy to monotherapy can often be carried out in the immediate postoperative period but the most appropriate timing of cessation of AED treatment has yet to be determined. Patients undergoing extratemporal resections and other forms of epilepsy surgery associated with less favourable postoperative seizure control may achieve comparatively less reduction in antiepileptic medication. We generally do not recommend stopping AEDs prior to one year after surgery.

Summary: Purpose: Other outcome measures besides seizure control must be considered when assessing the benefit of epilepsy surgery. We investigated the effect of preoperative psychosocial adjustment on postoperative depression in epilepsy patients followed up prospectively for 2 years after temporal lobectomy. Methods: The Washington Psychosocial Seizure Inventory (WPSI) evaluated psychosocial functioning; the Centre for Epidemiological Studies Depression Scale (CES-D) measured depression. Both were completed at baseline and follow-up. Results: Follow-up occurred in 39 temporal lobectomy patients at 2 years after surgery. Greatest improvement in depression scores was limited to patients with good seizure outcomes (seizure free, or marked reduction in seizure frequency), and seizure outcome was a significant predictor of postoperative depression. Despite this, preoperative scores on the emotional adjustment scale of the WPSI were most highly correlated with depression 2 years after surgery. To clarify this relation, moderated hierarchic regression suggested that good preoperative emotional adjustment (WPSI) was generally associated with less depression after surgery. Moreover, poorer preoperative adjustment combined with older age, generalized seizures, the finding of preoperative neurologic deficits, a family history of psychiatric illness, and/or a family history of seizures was related to higher depression scores 2 years after surgery. Conclusions: Depression after temporal lobectomy is dependent on a complex interaction of variables and can have a significant effect on indices of postoperative adjustment. The WPSI emotional adjustment scale may help to predict which patients are likely to be chronically depressed after surgery.

UNLABELLED The electrophysiologic effects of sevoflurane are not well characterized in humans. Among patients with refractory epilepsy, this study compared 1) electroencephalographic (EEG) interictal spike activity during wakefulness and sevoflurane anesthesia, and 2) electrocorticographically (ECoG) recorded interictal spike activity during sevoflurane and isoflurane anesthesia. We studied 12 patients undergoing insertion of subdural electrodes. Before commencing anesthesia, awake (baseline) EEG recordings were obtained. After inhaled induction, EEG interictal spike activity was evaluated during stable, normocapnic, and hypocapnic (Paco2 = 28-30 mm Hg), sevoflurane anesthesia administered at 1.5 times the minimum alveolar anesthetic concentration (1.5 MAC). Immediately after surgery, ECoG recordings were obtained from subdural electrodes during 1) 1.5 MAC isoflurane, 2) 0.3 MAC isoflurane, and 3) 1.5 MAC sevoflurane anesthesia. EEG spike frequency increased in all patients during sevoflurane anesthesia compared with awake recordings (P = 0.002). Compared with 0.3 MAC isoflurane anesthesia, ECoG interictal spike frequency was higher in all patients during 1.5 MAC sevoflurane anesthesia (P = 0.004) and in 8 of 10 patients during 1.5 MAC isoflurane anesthesia (P = 0.016). Under sufficiently rigorous conditions, both sevoflurane and isoflurane can provoke interictal spike activity at near burst-suppression doses. This property is more prominent with sevoflurane than isoflurane. IMPLICATIONS The results of this study suggest that the capacity to modulate neuroexcitability is a dose-dependent feature of volatile anesthetics that is manifested most prominently at near burst-suppression doses (i.e., 1.5 times the minimum alveolar anesthetic concentration) and is minimal or absent at low doses.