Cortical Spreading Depolarization in Chronic Subdural Hematoma: Bridging the Gap.

Cortical spreading depolarization (CSD) is recognized as a cause of transient neurological symptoms (TNS) in various clinical entities. Although scientific literature has been flourishing in the field of CSD, it remains an underrecognized pathophysiology in clinical practice. The literature evoking CSD in relation to subdural hematoma (SDH) is particularly scarce. Patients with SDH frequently suffer from TNS, most being attributed to seizures despite an atypical semiology, evolution, and therapeutic response. Recent literature has suggested that a significant proportion of those patients' TNS represent the clinical manifestations of underlying CSD. Recently, the term Non-Epileptical Stereoytpical Intermittent Symptoms (NESIS) has been proposed to describe a subgroup of patients presenting with TNS in the context of SDH. Indirect evidence and recent research suggest that the pathophysiology of NESIS could represent the clinical manifestation of CSD. This review should provide a concise yet thorough review of the current state of literature behind the pathophysiology of CSD with a particular focus on recent research and knowledge regarding the presence of CSD in the context of subdural hematoma. Although many questions remain in the evolution of knowledge in this field would likely have significant diagnostic, therapeutic, and prognostic implications.

Brivaracetam: First Canadian Experience in an Intractable Epilepsy Population.

OBJECTIVE: To evaluate the effectiveness and tolerability of brivaracetam (BRV) in a refractory epilepsy population in an outpatient clinical setting. METHODS: Retrospective medical information system review and self-report questionnaire for all patients treated with BRV until the end of 2017. RESULTS: Thirty-eight patients were included, 73.7% female and mean age 36.2. The mean number of antiepileptic drugs (AEDs) for previous use was 8.9, and for current use was 2.5. Mean seizure frequency in the last 3 months was 12 per month. At 3, 6, 12, and 15 months, the 50% responder rates were 36.1%, 32%, 41.2%, and 45.5%, respectively. Patients took BRV for a median duration of 8.25 months, ranging from 7 days to 60 months. Retention rate was 75.0%, 72.0%, 59.2%, and 47.9% at 3, 6, 12, and 15 months, respectively. Overall, the main reasons for discontinuation were adverse events (AEs) (52.3%), lack of efficacy (35.3%), or both (11.8%). The rate of total AEs was 60.5% according to medical records and 85.7% according to questionnaire, including mostly tiredness, psychiatric, and memory complaints. Psychiatric side effects occurred in 31.6% according to medical records and 47.4% according to questionnaire results, which is higher than previously reported and persisted throughout the study period. CONCLUSIONS: BRV appears to be a useful and safe add-on treatment, even in a very refractory group of patients. In this real-life clinical setting, psychiatric AEs were found at a higher rate than previously published.

Canadian epileptologists' counseling of drivers amidst guideline inconsistencies.

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 (p<0.001). CONCLUSIONS: 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.

The performance of bibliometric analyses in the health sciences.

A bibliometric analysis (BA) is a knowledge synthesis methodology aimed at quantitively summarizing large amounts of bibliometric data. We aimed to summarize the performance of BAs in the health sciences. We searched Scopus for BAs in the health sciences published prior to May 10, 2023. All identified studies were included. We performed a BA on these studies in two steps: performance analysis and science mapping. For the performance analysis, various indicators of scientific production were calculated using the bibliometrix R package. For the science mapping, VOSviewer was used to generate a co-authorship network and a keyword co-occurrence network. In total, 5,828 BAs were analyzed. Scientific production has exploded in the last years, with more than 1,500 BAs published in 2022 alone. Scientific impact (i.e. citations) has also been rising, although at a lesser pace. The mean number of citations per year per BA was 1.78. China was the most productive country, publishing more BAs than the nine other most productive countries combined. China paradoxically had a lower number of citations per publication compared with the nine other most productive countries. International collaborations were rare. Common BA themes included oncology, public health, neurosciences, mental health, artificial intelligence, and COVID-19. BAs are increasingly common in the health sciences, but their performance remains limited. More international collaborations and standardized guidelines could help improve their performance, notably the frequency at which they are cited.

Gamma knife surgery for refractory insular cortex epilepsy.

BACKGROUND: Resection of the epileptogenic insular cortex is surgically challenging. We sought to evaluate the potential of Gamma Knife surgery (GKS) for the treatment of pharmacoresistant insular cortex epilepsy (ICE) in patients who underwent GKS between 2005 and 2010. Adverse events and effects on seizure frequency were assessed. METHODS: Three cases of refractory ICE were treated by GKS between 2005 and 2010. RESULTS: Case 1 had refractory nonlesional ICE, proven by depth electrodes only partially helped by a left posterior insulectomy. Case 2 had refractory ICE due to a left insular cavernoma. Case 3 had refractory ICE, confirmed by an invasive study but complicated by transient dysphasia from contusion of Wernicke's area. The marginal and maximum radiation doses delivered were 20 and 40 Gy, respectively. Treatment volume ranged from 1.2 to 3.2 cm3. Two out of 3 patients experienced significant seizure reduction and the third had a worthwhile improvement (follow-up 30-76 months). Complete antiepileptic drug withdrawal was un-fortunately not possible. Complications included transient lightheadedness and new-onset seizures responsive to medical treatment, both in the same patient. CONCLUSION: GKS is a promising technique for selected drug-resistant ICE patients. Additional observations are necessary.

Sudden unexpected death in epilepsy (SUDEP): A bibliometric analysis.

OBJECTIVE: The literature on sudden unexpected death in epilepsy (SUDEP) has been evolving at a staggering rate. We conducted a bibliometric analysis of the SUDEP literature with the aim of presenting its structure, performance, and trends. METHODS: The Scopus database was searched in April 2023 for documents explicitly detailing SUDEP in their title, abstract, or keywords. After the removal of duplicate documents, bibliometric analysis was performed using the R package bibliometrix and the program VOSviewer. Performance metrics were computed to describe the literature's annual productivity, most relevant authors and countries, and most important publications. Science mapping was performed to visualize the relationships between research constituents by constructing a country collaboration network, co-authorship network, keyword co-occurrence network, and document co-citation network. RESULTS: A total of 2140 documents were analyzed. These documents were published from 1989 onward, with an average number of citations per document of 25.78. Annual productivity had been on the rise since 2006. Out of 6502 authors, five authors were in both the list of the ten most productive and the list of the ten most cited authors: Devinsky O, Sander JW, Tomson T, Ryvlin P, and Lhatoo SD. The USA and the United Kingdom were the most productive and cited countries. Collaborations between American authors and European authors were particularly rich. Prominent themes in the literature included those related to pathophysiology (e.g., cardiac arrhythmia, apnea, autonomic dysfunction), epilepsy characteristics (e.g., epilepsy type, refractoriness, antiseizure medications), and epidemiology (e.g., incidence, age, sex). Emerging themes included sleep, genetics, epilepsy refractoriness, and non-human studies. SIGNIFICANCE: The body of literature on SUDEP is rich, fast-growing, and benefiting from frequent international collaborations. Some research themes such as sleep, genetics, and animal studies have become more prevalent over recent years.

Use of non-medical cannabis in epilepsy: A scoping review.

Objective: The use of medical cannabis among people with epilepsy (PWE) has been garnering increasing interest. In this scoping review, we aimed to summarize the literature on recreational/non-medical cannabis (NMC) use in PWE, focusing on the experience, habits, and beliefs of PWE regarding NMC. Methods: Four databases (OVID Medline, OVID Embase, Ovid APA PsycInfo, and Web of Science) were searched for studies describing NMC use in PWE. NMC was defined as cannabis products procured from sources other than by prescription. Studies that consisted in original research and that detailed the experience, habits, and/or beliefs of PWE regarding NMC use were included in the analysis. Data pertaining to study identification, demographics, NMC use, and epilepsy characteristics were extracted. Descriptive statistical analyses and reflexive thematic analyses were performed to map these data. Results: In total, 3,228 records were screened, and 66 were included for analysis: 45 had mainly adult samples, whereas 21 had mainly pediatric samples. Most studies were published after 2010, originated from the USA, and were cross-sectional. The median number of PWE using cannabis in these studies was 24.5 (1-37,945). No studies showcased elderly PWE, and most had predominantly Caucasian samples. The lifetime prevalence of NMC use in PWE was variable, ranging between 0.69 and 76.8%. Factors frequently associated with NMC use in PWE were male sex, younger adult age, and lower education status. Children with epilepsy took NMC primarily for seizure control, using high CBD/THC ratios, and only orally. Adults with epilepsy took NMC for various reasons including recreationally, using variable CBD/THC ratios, and predominantly through smoking. The majority of PWE across all studies perceived that NMC aided in seizure control. Other aspects pertaining to NMC use in PWE were rarely reported and often conflicting. Conclusion: The literature on NMC use in PWE is sparse and heterogeneous, with many salient knowledge gaps. Further research is necessary to better understanding the experience, habits, and beliefs of PWE pertaining to NMC.

Association Between Frailty and Antiseizure Medication Tolerability in Older Adults With Epilepsy.

BACKGROUND AND OBJECTIVE: Frailty is an important aspect of biological aging, referring to the increased vulnerability of individuals with frailty to physical and psychological stressors. While older adults with epilepsy are an important and distinct clinical group, there are no data on frailty in this population. We hypothesize that frailty will correlate with the seizure frequency and especially the tolerability of antiseizure medications (ASMs) in older adults with epilepsy. METHODS: We recruited individuals aged 60 years or older with active epilepsy from 4 Canadian hospital centers. We reported the seizure frequency in the 3 months preceding the interview, while ASM tolerability was quantified using the Liverpool Adverse Events Profile (LAEP). We applied 3 measures of frailty: grip strength as a measure of physical frailty, 1 self-reported score (Edmonton frail score [EFS]), and 1 scale completed by a healthcare professional (clinical frailty scale [CFS]). We also administered standardized questionnaires measuring levels of anxiety, depression, functional disability, and quality of life and obtained relevant clinical and demographic data. RESULTS: Forty-three women and 43 men aged 60-93 years were recruited, 87% of whom had focal epilepsy, with an average frequency of 3.4 seizures per month. Multiple linear regression and zero-inflated negative binomial regression models showed that EFS and CFS scores were associated with decreased ASM tolerability, each point increase leading to 1.83 (95% CI: 0.67-4.30) and 2.49 (95% CI: 1.27-2.39) point increases on the LAEP scale, respectively. Neither the EFS and CFS scores nor grip strength were significantly associated with seizure frequency. The EFS was moderately correlated with depression, anxiety, quality of life, and functional disability, demonstrating the best construct validity among the 3 tested measures of frailty. DISCUSSION: The EFS was significantly, both statistically and clinically, associated with ASM tolerability. It also showed multiple advantages in performance while assessing for frailty in older adults with epilepsy, when compared with the 2 other measures of frailty that we tested. Future studies must focus on what role the EFS during epilepsy diagnosis may play in ASM selection among older adults with epilepsy.

Epileptiform asymetries and treatment response in juvenile myoclonic epilepsy.

BACKGROUND: Epileptiform electroencephalogram (EEG) asymmetries are not uncommon in juvenile myoclonic epilepsy (JME) and can contribute to the misdiagnosis of this syndrome. The objective of this study is to further characterize patients with focal or asymmetric epileptiform electroencephalographic abnormalities and more specifically in terms of response to treatment. Controversial data exists in the literature concerning this issue. METHODS: We retrospectively reviewed clinical and EEG data of a group of consecutive JME patients followed at our Epilepsy Service. The first EEG available for each patient was reviewed blindly by two independent electroencephalographers. RESULTS: Twenty-eight patients with JME were identified: 11 (39.3%) were resistant to at least one appropriate anti-epileptic drug (AED), including valproate, lamotrigine, topiramate or levetiracetam. All patients except two had generalized epileptiform abnormalities. Overall, EEG asymmetries were detected in 57.1% of the cases. The proportion of EEG asymmetries between AED-sensitive group (52.9%) and AED-resistant group (63.5%) did not reach statistical significance. Concordance between examiners for identification of EEG asymmetries was good. Analysis of patients with and without asymmetries showed no statistically significant differences in comparisons of age, family history of seizure, presence of polyspike and slow wave, photosensitivity and timing of EEG related to the onset of treatment. CONCLUSION: Asymmetric electroencephalographic abnormalities are frequent in patients with JME. These features should not be misinterpreted as being indicative of partial epilepsy. In our group, asymmetries were not associated with resistance to treatment.

Nonepileptic, Stereotypical, and Intermittent Symptoms (NESIS) in Patients With Subdural Hematoma: Proposal for a New Clinical Entity With Therapeutic and Prognostic Implications.

BACKGROUND: Transient neurological symptoms (TNS) are frequent in patients with subdural hematomas (SDH) and many will receive a diagnosis of epilepsy despite a negative workup. OBJECTIVE: To explore if patients with TNS and a negative epilepsy workup (cases) evolved differently than those with a positive EEG (controls), which would suggest the existence of alternative etiologies for TNS. METHODS: We performed a single-center, retrospective, case-control study of patients with TNS post-SDH. The demographics and clinical and semiological features of cases and controls were compared. The outcome and response to antiepileptic drugs were also assessed and a scoring system developed to predict negative EEG. RESULTS: Fifty-nine patients with SDH-associated TNS were included (39 cases and 20 controls). Demographic characteristics were comparable in both groups. Dysphasia and prolonged episodes were associated with a negative EEG. Clonic movements, impaired awareness, positive symptomatology, complete response to antiepileptic drugs, and mortality were associated with a positive EEG. Using semiological variables, we created a scoring system with a 96.6% sensitivity and 100% specificity in predicting case group patients. The differences observed between both groups support the existence of an alternative etiology to seizures in our case group. We propose the term NESIS (NonEpileptic, Stereotypical, and Intermittent Symptoms) to refer to this subgroup and hypothesize that TNS in these patients might result from cortical spreading depolarization. CONCLUSION: We describe NESIS as a syndrome experienced by SDH patients with specific prognostic and therapeutic implications. Independent validation of this new entity is now required.

A novel locus for idiopathic generalized epilepsy in French-Canadian families maps to 10p11.

Idiopathic generalized epilepsy (IGE) has evidence of a strong genetic etiology. We conducted genomewide linkage analysis for genes responsible for familial IGE in French-Canadian pedigrees. Twenty families segregating autosomal dominant epilepsy were collected. Four larger IGE families sufficiently powerful for independent linkage analysis were genome-scanned and follow-up fine mapping was performed over regions with LOD scores >3.0. The genotyping of 16 smaller families was carried out at significantly linked loci for supportive linkage analysis and haplotype comparisons. One of the four families provided a significant linkage result at marker D10S1426 on chromosome 10 (two-point LOD score = 3.05, theta = 0, multipoint LOD score = 3.18). Fine mapping revealed a segregating haplotype and key recombination breakpoints, suggesting a candidate gene interval of 6.5 Mb. Multipoint linkage analyses using the additional 16 families yielded a maximum LOD score under heterogeneity of 4.23 (alpha = 0.34) at this locus. Evaluation of recombination breakpoints in these families narrowed the candidate region to 1.7 Mb. Sequencing of the two known genes in this region, NRP1 and PARD3, was negative for mutation. Replication of linkage to this locus in other cohorts of IGE families is essential to characterize the underlying genetic mechanism for the disease.

Pilot study of EEG in neonates born to mothers with gestational diabetes mellitus.

BACKGROUND: The goal was to evaluate whether there was neurodevelopmental deficits in newborns born to mothers with gestational diabetes mellitus (GDM) compared to control newborns born to healthy mothers. METHODS: Forty-six pregnant women (21 controls and 25 GDM) were recruited. Electroencephalogram (EEG) was recorded in the newborns within 48 h after birth. The EEG signal was quantitatively analyzed using power spectral density (PSD); coherence between hemispheres was calculated in paired channels of frontal, temporal, central and occipital regions. RESULTS: The left centro-occipital PSD in control newborns was 12% higher than in GDM newborns (p = 0.036) but was not significant after adjustment for gestational age. While coherence was higher in the frontal regions compared to the occipital regions (p < 0.001), there was no difference between the groups for the fronto-temporal, frontal-central, centro-occipital and tempo-occipital regions. CONCLUSION: Our results support that EEG differences between groups were mainly modified by gestational age and less by GDM status of the mothers. However, there is a need to confirm this result with a higher number of mother-newborns. Quantitative EEG in GDM newborns within 48 h after birth is feasible. This study emphasizes the importance of controlling blood glucose during GDM to protect infant brain development.

Triphasic waves versus nonconvulsive status epilepticus: EEG distinction.

BACKGROUND: Triphasic waves (TWs) and generalized nonconvulsive status epilepticus (GNCSE) share morphological features that may create diagnostic ambiguity. OBJECTIVE: To describe electroencephalographic differences between TWs and GNCSE. METHODS: We retrospectively compared the electroencephalograms (EEGs) of two groups of patients presenting with decreased level of consciousness; those with TWs associated with metabolic encephalopathy and those with GNCSE. We studied the following: demographics, etiology and EEG morphological features. All EEGs were classified blindly (TWs or GNCSE) by two expert EEGers. Agreement between experts and concordance with clinical diagnosis were measured. RESULTS: We analysed 87 EEGs (71 patients) with TWs and 27 EEGs (13 patients) with GNCSE. Agreement between experts and concordance with clinical diagnosis were excellent. When compared to TWs, epileptiform discharges associated with GNCSE had a higher frequency (mean=2.4Hz vs 1.8Hz) (p<0.001), a shorter duration of phase one (p=0.001), extra-spikes components (69% vs 0%) (p<0.001) and less generalized background slowing (15.1% vs 91.1%) (p<0.001). Amplitude predominance of phase two was common with TWs (40.8% vs 0%) (p=0.01). Lag of phase two was absent in all cases of GNCSE but present in 40.8% of patients with TWs. Noxious or auditory stimulation frequently increased the TWs (51%) while it had no effect on the epileptiform pattern (p=0.008). CONCLUSIONS: Certain EEG morphological criteria and the response to stimulation are very helpful in distinguishing TWs from GNCSE.

Fatty acid profile in cord blood of neonates born to optimally controlled gestational diabetes mellitus.

OBJECTIVE: To evaluate the fatty acid profile of cord blood phospholipids (PL), cholesteryl esters (CE), triglycerides (TG) and non-esterified fatty acids (NEFA) in neonates born to mothers with gestational diabetes mellitus (GDM) compared to non-diabetic mothers. METHODS: The offspring of 30 pregnant women (15 non-diabetic controls, 15 with diet- or insulin-controlled GDM) were recruited before delivery. Cord blood was collected. After lipid extraction, PL, CE, TG and NEFA were separated by thin layer chromatography and analysed by gas chromatography. RESULTS: In GDM vs. control mothers, maternal glycated haemoglobin (A1C, mean±SD) was not different between groups: 5.3±0.5% vs. 5.3±0.3% (p=0.757), respectively. Cord plasma fatty acids were not different in TG, CE and NEFA between GDM and non-diabetic mothers. However, in PL, levels of palmitate, palmitoleate, oleate, vaccinate and di-homo-gamma-linolenate were significantly lower, with a trend for lower arachidonate (p=0.078), in neonates born to GDM mothers compared to controls. CONCLUSION: In contrast to other studies on cord blood docosahexaenoic acid (DHA) levels in GDM mothers, we did not found lower levels of DHA in cord PL, CE, TG or NEFA in neonates born to GDM compared to non-diabetic mothers.

Gamma Knife surgery for hypothalamic hamartomas causing refractory epilepsy: preliminary results from a prospective observational study.

OBJECT: Hypothalamic hamartomas (HHs) are congenital lesions typically presenting with medically refractory epilepsy. Open or endoscopic surgical procedures to remove or disconnect the hamartoma have been reported to be effective but are associated with significant morbidity. The authors of studies on Gamma Knife surgery for HHs have reported an encouraging rate of epilepsy resolution with minimal side effects. At the Centre Hospitalier Universitaire de Sherbrooke, the authors have undertaken a prospective observational study of the outcomes of patients who underwent radiosurgery for HHs. METHODS: Patients were included in the study if they had an HH, refractory epilepsy, and no other suspected seizure focus. After radiosurgery, seizure status was assessed every 3 months and reported using the Engel Classification. Quality of life evaluation was performed annually using a standardized questionnaire, and neuropsychological evaluation was performed after 2 years. RESULTS: Nine patients were included in the study. They ranged in age from 12 to 57 years. Epilepsy began in infancy in all cases and was refractory to standard antiepileptic drugs. The patients received an average of 2 antiepileptic drugs before undergoing radiosurgery. Using the Régis Classification, 6 patients had smaller hamartomas (Grade I-III) and underwent treatment of the entire lesion, using a margin dose of 14-20 Gy. Treatment volume ranged from 0.3 to 1.0 ml. Three patients had larger lesions (Grade IV-VI) for which a radiosurgical disconnection was attempted, targeting the area of attachment to the hypothalamus. For those patients, the margin dose was 15 or 16 Gy, with treatment volume ranging from 0.8 to 1.8 ml. In all patients, the radiation dose received by the optic pathways was kept below 10 Gy. Disconnection led to no improvement in epilepsy (Engel Class IV). Four patients in whom the entire lesion was treated are now seizure free (Engel Class I), with another having only rare seizures (Engel Class II). Quality of life and verbal memory were improved in those patients with more than 3 years of follow-up. No adverse event occurred after radiosurgery. CONCLUSIONS: Radiosurgery safely and effectively controlled the epileptic disorder in patients with HHs when the entire lesion could be targeted. Radiosurgical disconnection is ineffective and cannot be recommended.