Background: Background: Responsive Neurostimulation (RNS) has proven efficacy in treating medically resistant epilepsy as an intracranial system detecting, recording and treating seizures automatically. No information exists pertaining to artifact characteristics of RNS findings in scalp EEG. Methods: A 30 year-old female was diagnosed using intracranial electroencephalography(iEEG), with bi-insular epilepsy, of unknown cause. She presented large number of focal unaware non-motor seizures and seizures with progression to bilateral tonic-clonic. She was implanted with bi-insular RNS. Results: During scalp EEG recordings, a prominent artifact was seen corresponding to an automatized discharge suspectedly evoked by the RNS trying to minimize the frequent epileptiform activity in her case. Figure 1 and 2 depict these findings. Conclusions: Artifact seen by the RNS in scalp EEG has not been previously described in scientific literature. These findings must be identified to better characterize the role of the RNS in EEG and treatment of seizure activity visible on scalp recordings.

Background: Standard of care treatment for adult intracranial ependymoma patients includes maximal safe surgical resection, while the role for adjuvant radiotherapy remains unclear with existing data from small retrospective series’. Accordingly, we built a multi-institutional cohort to assess the prognostic value of adjuvant radiotherapy and other clinical factors in these patients. Methods: Patients managed for adult intracranial ependymomas from 1968 onwards within the University Health Network in Toronto, The University of Oklahoma Health Sciences Center, and The Ottawa Hospital were identified. Multivariate models assessing the prognostic value of clinical factors were built using variables with known prognostic value and/or significance in univariate Cox models. Results: Of 122 ependymomas, 71% were infratentorial, 78% grade two, 55% gross/near-totally resected (GTR/NTR), and 65% treated with adjuvant radiotherapy. Multivariate analyses identified GTR/NTR (vs. subtotal resection; HR=0.2, 95%CI=0.1–0.4, p<0.0001) and cranial (HR=0.5, 95%CI=0.2–1.1) or craniospinal (HR=0.2, 95%CI=0.04–0.5) radiotherapy receipt (p=0.01) as independent statistically significant predictors of more favourable PFS. Grade II pathology (vs. grade III; HR=0.2, 95%CI=0.05–0.6, p=0.006) and GTR/NTR (vs. subtotal resection; HR=0.1, 95%CI=0.03–0.3, p=0.0001) were independent statistically significant predictors of better OS. Conclusions: This work confirms the importance of maximal safe resection for adult intracranial ependymomas and establishes that adjuvant radiotherapy improves progression-free survival in these patients.

Background: Nusinersen is approved for spinal muscular amyotrophy type I,II,III and is available for adult and pediatric populations since January 2019 at the CHU de Québec-UL. Methods: Patients who received at least one dose of nusinersen between January 2019 and March 2021 were included. Required information was gathered from patients’ charts. Results: Ten adults (70 injections) and 23 infants and children (202 injections) were included. No child but two adults stopped the therapy for personal reasons. Tests were performed at 0, 6, 18, 24 months when possible to assess efficacy, tolerability and quality of life perception (Table 1). Preliminary data shows stabilization or improvement for many tests. Conclusions: Nusinersen is well tolerated. Favorable effects were observed in both populations. A monitoring is still imperative for an objective assessment and for evaluation of the most relevant tests. Long term benefits remain to be demonstrated but results are encouraging.

Background: Simulation-based educations’ prevalence within clinical neuroscience is on the rise, however investigation into what environment is most conducive to optimizing learning performance is limited. We aimed to determine whether training a simple-to-complex (progressive) sequence would result in superior learning compared to complex-to-simple (mixed) or complex-only sequences. Methods: A three-arm, prospective, randomised experiment was conducted to determine the effects on novice learner LP performance and cognitive load during learning and a very complex simulated reality assessment test 9-11 days later. Results: During learning, sterility breaches decreased linearly over time (p<.01) with no group differences, and accuracy was higher in the progressive group compared to complex-only (p<.01) and trended in the mixed group (p<.09). Across the learning phase cognitive load increased in the progressive group (p<.01) and decreased across the mixed group (p<.01). At assessment, there were no group differences in number of sterility breaches (p=.66), needle passes (p=.68) or cognitive load (p=.25). Conclusions: Contrary to our hypothesis, equivocal assessment performance was found across groups. Our results suggest that successive progression in complexity of simulation does not increase novice learner outcomes. Further, a “one-size fits all” approach to simulated environment complexity in clinical neurosciences education may be warranted given equivocal learning and less resources necessary.

Background: Rotating internal medicine (IM) residents do not feel adequately prepared to approach patients with neurologic issues. The purpose of this project was to conduct a needs assessment to determine the optimal components and delivery of a neurology curriculum for internal medicine residents. Methods: We utilized a mixed-methods design and recruited participants through a combination of purposive and convenience sampling. We conducted interviews with IM residents (n=12) and focus groups with neurology residents (n=7) and neurology staff (n=8). IM residents completed entry- and post-call surveys while on a neurology rotation. Results: Themes according to Kern’s framework for curriculum development: 1. Problem: Discomfort and perception of under-preparedness amongst IM trainees 2. Needs Assessment: What the learners (stakeholders) think they need to know vs. what their teachers want them to know vs external requirements (Royal College) 3. Goals/objectives: What content is relevant for clinical requirements vs assessments? 4. Methods and setting: Didactic vs bedside vs virtual 5. Implementation of the curriculum 6. Evaluation and feedback Conclusions: Our findings illustrate a possible mismatch between internal medicine residents’ needs and neurologist teachers’ expectations in teaching neurology. Addressing learners’ needs could enhance neurology knowledge and sense of preparedness when encountering patients with neurologic issues.

Background: Mounting evidence supports aerobic exercise as a promising treatment option for individuals experiencing persistent post-concussion symptoms beyond four weeks. The purpose of this review was to determine whether initiating structured aerobic exercise within the early period (first two weeks) following concussion affects symptom recovery compared to standard care. Methods: A systematic literature search was performed using MEDLINE, Embase, PsycINFO and CENTRAL databases, combining keywords: (brain concussion, post-concussion syndrome, mild traumatic brain injury) AND (exercise, exercise therapy, physical activity, kinesiotherapy). Results were limited to Randomized Controlled Trials (RCTs). All selected articles underwent quality assessment. Results: The search generated 112 unique abstracts, of which 5 met inclusion criteria. Sample sizes ranged from 16 to 103 participants. Of the four studies that were able to analyze between-group differences, one showed significantly faster recovery in the early aerobic exercise group compared to control, while three showed no significant difference. Two studies demonstrated a trend toward faster initial symptom resolution in the early exercise group. Conclusions: Preliminary RCT evidence suggests that aerobic exercise initiated in the early postconcussion period does not exacerbate symptoms or prolong recovery time, and may potentially hasten recovery. Larger, more rigorous RCTs are required to define the optimal exercise parameters to facilitate symptom recovery.

Background: The circle of Willis (CoW) and cervical carotid arteries are important sources of collateral flow during acute large vessel occlusion (LVO) in the anterior circulation. We examined the anatomical components of the circle and the cervical carotid arteries to determine relationship to acute stroke severity. Methods: Consecutive patients with acute LVO who underwent EVT were assessed. Measurements were made of the luminal diameters of 16 anatomical vascular components. Admission NIHSS, ASPECTS and mCTA collateral scores were statistically analyzed for any relationship to vascular measurements. Results: 100 patients were studied. No relationship was found between the collateral Willisian pathways and measures of stroke severity. However, the ophthalmic arteries exhibited a relationship to stroke severity. In adjusted analysis, 1-mm increases in the ipsilateral and contralateral ophthalmic artery diameter were independently associated with a 4.80-point decrease and a 6.31-point increase in the NIHSS scale, respectively. Similarly, a 1.53-point increase and a 2.62-point decrease in the ASPECTS. In the neck a majority showed 0-55% stenosis, with no stenosis between 55% and 95%, and 14% at 95% to 100%. Conclusions: Stroke severity and collateral during LVO is unrelated to Willisian collateral. Ophthalmic artery calibers are related. Acute progression of 55-95% stenoses to complete occlusion occurs in LVO stroke

Background: Predicting outcomes after endovascular treatment (EVT) for acute ischemic stroke with baseline variables remains a challenge. We assessed the performance of stroke outcome prediction models for EVT in acute ischemic stroke in an iterative fashion using baseline, treatment-related and post-treatment variables. Methods: Data from the ESCAPE-NA1 trial were used to build 4 outcome prediction models using multi-variable logistic regression: Model 1 included baseline variables only that are available prior to treatment decision-making, model 2 included additional treatment-related variables, model 3 additional early post-treatment variables, and model 4 additional late post-treatment variables. The primary outcome was 90-day modified Rankin Scale score 0-2. Model performance was compared using the area under the curve (AUC). Results: Among 1,105 patients, good outcome was achieved by 666 (60.3%). When using baseline variables only (model 1), the AUC was 0.74 (95%CI:0.71-0.77); this iteratively improved when treatment and post-treatment variables were added to the models (model 2: AUC 0.77,95%CI: 0.74-0.80, model 3: AUC 0.80,95%CI:0.77-0.83, model 4: AUC 0.82, 95%CI:0.79-0.85). Conclusions: Predicting EVT outcomes using baseline variables alone is inaccurate in one in four patients, and may be inappropriate for patient selection. Even the most comprehensive models with treatment-related and post-treatment factors involve considerable uncertainty.

Background: MAiD became legal in Canada in 2015, with Bill C-14 delineating eligibility criteria and access. Previous research found families are intimately involved with decision-making, with conflicting perspectives on how they cope.

Our study sought to learn about the experiences of family members, and determine what supports might be beneficial to improve MAiD delivery and aftercare. Methods: We conducted hour-long semi-structured interviews with 20 family members of individuals who had MAiD. Interviews took place by telephone or virtually via MS Teams, and transcripts were analyzed using an iterative coding process and thematic analysis. Results: Prominent themes emphasized the importance of respecting autonomy, decision-making, and allowing people to regain a sense of control, particularly with so much taken away.

The death itself was described as peaceful. Interviewees were overwhelmingly filled with relief and gratitude for being able to respect the individual’s wishes.

Interviewees spoke of importance of support for themselves, and the desire to build a network of individuals with similar experiences; to share their stories, grieve together, and support the next generation. Conclusions: These results will help improve MAiD delivery and aftercare in Nova Scotia, by informing, developing and enabling access to resources for individuals who accompany a family member on their end-of-life journey.

Background: Neurofibromatosis 1 and 2 (NF1 and NF2) are autosomal dominant genetic disorders caused by mutations in tumour suppressor genes. Methods: We conducted a systematic review of the incidence and prevalence of NF1 and NF2 in OVID Medline, OVID Embase, Web of Science, and Cinahl. We included studies until February 19, 2021, that identified cases based on established criteria. Studies were appraised for quality using the Joanna Briggs Institute Prevalence Critical Appraisal tool. Pooled incidence and prevalence rates were estimated through meta-analysis. Results: Of 1,936 studies, 1,866 were irrelevant after title and abstract screening. Sixteen of 69 studies with full text assessment were included for full review: 13 regarding NF1 and 6 regarding NF2. Incidence rates for NF1 and NF2 ranged from 1/11,494 to 1/1,871 and 1/62,185 to 1/33,000 respectively. Prevalence rates for NF1 and NF2 ranged from 1/6,238 to 1/1,001 and 1/600,000 to 1/56,161 respectively. Meta-analysis will be presented at the conference. Conclusions: An accurate estimate of the incidence and prevalence of NF1 and NF2 will offer more insight into health resource allocation. Increased funding and resources for the development of early diagnostic and treatment tools for NF1 and NF2 may improve the quality of life of patients.

Background: Objective markers of disease progression are needed for patients with multiple sclerosis (MS). Increased randomness in neural networks is hypothesized to be an important cause of morbidity that can be objectified using graph theory. Methods: We use voxel-based structural similarity determined from T1-weighted MRI scans of 23 patients with MS receiving autologous stem cell transplant (ASCT) to compute cortical covariance network parameters. We examine associations between measures of cortical integration or segregation and biochemical/clinical measures of cortical health or function using Spearman correlation coefficients. P<0.05 was considered significant. Results: Path length increase was associated with markers of greater inflammation (ρ=0.56,P<.046) at baseline and reduced Naa/Cr ratio (P<.041) at 12 months. Reduced lambda was associated with markers of greater grey matter atrophy (ρ=0.55,P<.019) after 12 months and lower cognition (ρ=0.56,P<.008) at 12 months. Reduced clustering was associated with higher neurofilament (ρ=-0.68,P<.010) at baseline, greater white matter atrophy (ρ=0.62,P<.006) after 12 months, lower 2-second PASAT performance (ρ=0.56,P<.011) at baseline, and reduced Naa/Cr ratio (P<.001) at 12 months. Conclusions: Reduced cortical integration and segregation (random network features) co-occur with unfavourable markers of cortical health and function in patients with MS receiving ASCT. Network features show promise as important longitudinal markers of patient status and progression.

Background: Approximately 20-40% of patients with non-small cell lung cancer (NSCLC) will develop brain metastases (BM). The aim of this study was to investigate if Epidermal Growth Factor Receptor (EGFR) status of NSCLC alters the radiological appearances of BM. Also to compare differences in imaging features of BM occurring from EGFR-mutated NSCLC during treatment with Tyrosine Kinase Inhibitors (TKI) versus prior to treatment. Methods: A retrospective study was performed over a 5 year period of all patients with histologically proven NSCLC with BM and known EGFR status. 72 patients met the inclusion criteria. Radiological features were reviewed as well as number, size and location of BM. Results: 18/72 patients had EGFR-mutated NSCLC and of these 9 presented with BM while on TKI treatment. Patients with EGFR-mutated NSCLC had statistically significant higher occurrence of multiple BM (p=0.029) and BM in a central location (p=0.027). BM that occurred during TKI treatment appeared smaller and with minimal surrounding oedema. Conclusions: Given the propensity for multiple BM in EGFR-mutated NSCLC, vigilant imaging follow up would need to be considered. BM presenting while on TKI were more subtle, especially on Computed Tomography (CT), therefore careful follow up with Magnetic Resonance Imaging (MRI) may be required.

Background: The aim of this study is to investigate the differences in the radiological appearances of brain metastases (BM) in metastatic melanoma (MM) relative to BRAF mutation status. As well as to compare imaging differences in BM that occur prior to starting and during systemic therapy. Methods: A retrospective study was done over a 5 year period. Patients with MM with BM and known BRAF status were identified. 38 met the inclusion criteria. Imaging features on both Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) were reviewed. Results: Irrespective of BRAF mutation status, BM in MM tended to have a peripheral location with 30/38 cases having BM in the cerebral cortex. BRAF positive MM had a higher frequency of irregularly enhancing BM on CT and higher occurrence of BM showing high T1 signal on MRI. BM found during systemic treatment, regardless of BRAF status, showed less surrounding oedema, were smaller and harder to spot on CT. Conclusions: Understanding imaging features based on genetics could inform future management. The subtle features of BM on CT during systemic therapy means careful follow up with MRI may be indicated to confirm the diagnosis and to more accurately assess the burden of brain disease.

Background: Vascular closure devices (VCDs) are routinely used in both neurovascular and vascular interventional procedures. The purpose of our study was to assess the safety and efficacy of the VCDs for diagnostic and therapeutic neurovascular and vascular procedures. Methods: The study was approved by the University of Manitoba research ethics board. A retrospective review was conducted of the database between January 2017 and December 2019. The data was collected from the Picture Archiving and Communication System (PACS) and collected in an excel spreadsheet. Patient demographics and clinical information was collected. Descriptive statistics and chi-squared tests were performed using STATA 13 software. A p<0.05 was considered significant. Results: VCD was used in a total of 2072 patients. VCDs were successfully deployed in 94% with 6% failure. Immediate perioperative complications were seen in 6.2% patients. The complication rates were significantly (p=0.025) associated with the type of procedure. Complications were seen significantly (p=0.044) higher in outpatients compared to inpatients and those from emergency room. Conclusions: VCDs were successfully deployed in 96VCDs were successfully deployed in 94% of the patient with 6% perioperative complications. Most of the complications were minor and complications were more commonly associated with outpatients procedures and with diagnostic vascular procedures.

Background: A basic understanding of localization for a given set of focal neurological deficits is essential for accurate acquisition and interpretation of neuroimaging. Relying on often-limited clinical information, neuroradiologists must choose the most appropriate imaging modality and tailor a study to best identify the culprit lesion to allow for accurate interpretation. Methods: A multiple-choice quiz was designed including clinical vignettes localizing to lesions within the central (CNS) and peripheral nervous systems (PNS). The quiz was pilot-tested and refined before distribution as an electronic survey to practicing neuroradiologists and fellows within newsletters from the American Society for Neuroradiology and Canadian Neurological Sciences Federation. Results: The quiz was begun by 45 neuroradiologists and completed in its entirety by 22. Most respondents were working at urban academic/teaching hospitals(81%) in the USA(42%). The majority (90%) report no clinical neurology rotation during their training. Respondents identified a high proportion (88%) of correct answers in questions about brainstem localizations. Fewer correct answers were selected in questions describing seizure semiology (44%) or flaccid weakness (59%). Conclusions: The small size of our study limits interpretation and generalizability of the findings. Identification of a potential gap in neuroradiology education relating to localization of more complex CNS and PNS presentations merits further exploration.

Background: There are no recommendations regarding endovascular treatment (EVT) for patients with acute ischemic stroke (AIS) due to primary medium vessel occlusion (MeVO). The aim of this study was to examine the willingness to perform EVT among stroke physicians in patients with mild, yet personally-disabling deficits due to MeVO. Methods: In an international survey consisting of 4 cases of primary MeVOs, participants were asked whether the presence of personally-disabling deficits would influence their decision-making for EVT despite the patients having low NIHSS scores. Decision rates were calculated based on physician characteristics. Clustered univariable logistic regression was performed. Results: 366 participants from 44 countries provided 2562 answers. 56.9% opted to perform EVT in scenarios in which the deficit was relevant to the patient’s profession versus 41.0% in which no information regarding patient profession was provided (RR1.39, p<0.001). The largest effect sizes were seen for female participants (RR1.68, 95%CI:1.35-2.09), participants >60 years (RR1.61, 95%CI:1.23-2.10), with more neurointervention experience (RR1.60, 95%CI:1.24-2.06), and who personally performed >100 EVTs per year (RR1.63, 95%CI:1.22-2.17). Conclusions: The presence of a patient-relevant deficit in low NIHSS AIS due to MeVO is an important factor for EVT decision-making. This may have relevance for the conduct and interpretation of low NIHSS EVT randomized trials.

Background: Thrombus embolization during endovascular treatment (EVT) occurs in up to 9% of cases, making secondary medium-vessel occlusions (MeVOs) of particular interest to neurointerventionalists. We sought to gain insight into the current EVT approaches for secondary MeVO stroke in an international case-based survey as there are currently no clear recommendations for EVT in these patients. Methods: Participants were presented with three secondary MeVO cases, each consisting of three case-vignettes with changes in patient neurological status (improvement, no change, unable to assess). Clustered multivariable logistic regression analyses were used to assess factors influencing the decision to treat. Results: 366 physicians from 44 countries took part. The majority (54.1%) were in favor of EVT. Participants were more likely to treat occlusions in the anterior M2/3 (74.3%; risk ratio [RR]2.62, 95%CI:2.27-3.03) or A3 (59.7%; RR2.11, 95%CI:1.83-2.42) segment, compared to the M3/4 segment (28.3%;reference). Physicians were less likely to pursue EVT in patients with neurological improvement (49.9% versus 57.0%; RR0.88, 95%CI:0.83-0.92). Interventionalists and more experienced physicians were more likely to treat secondary MeVOs. Conclusions: Physician’s willingness to treat secondary MeVOs endovascularly is limited and varies per occlusion location and change in neurological status. More evidence on the safety and efficacy of EVT for secondary MeVO stroke is needed.

Background: We evaluated (1) the predictive accuracy and (2) multi-observer reliability of non-contrast CT markers of hematoma expansion (HE). Methods: In 124 patients with spontaneous intracerebral hemorrhage, two investigators documented the presence of six density (Barras density, hypodensity, black hole, swirl, blend, fluid level) and three shape (Barras shape, island, satellite) expansion markers, with discrepancies resolved by a third rater. We defined HE as any one of (1) >6 mL absolute or >33% relative growth of the intraparenchymal hematoma or (2) an absolute growth of >1 mL or new development of intraventricular hematoma. A subsample of 60 patients was used for the inter-observer reliability study in 13 raters. Seven raters participated in the intra-rater study. Results: The sensitivity of markers for HE varied between 4% (fluid level) and 78% (satellite), while specificity ranged from 37% (swirl) to 97% (black hole). Almost perfect inter-rater agreement was observed for the swirl (0.89) and fluid level (0.83) markers, while hypodensity (0.65) showed substantial agreement. Only the blend and fluid level markers achieved substantial intra-rater agreement (> 0.6) in all raters. Conclusions: Non-contrast CT markers of HE showed lower reliability and predictive accuracy than previously reported. Future studies should address means to improve NCCT-based HE prediction.

Background: Ruptured Intracranial Infected Aneurysms (IIAs) are a relatively rare phenomenon, but they portend high mortality. To our knowledge, there are no Canadian studies on IIA with paucity of data on experiences as well. Our purpose is to share experience of a single Canadian tertiary centre in managing ruptured IIA and to conduct a systematic review. Methods: Retrospective case series review of adult patients with ruptured IIA treated at our institution. Secondly, we conducted a systematic review of literature on ruptured IIA between 2011-2021 inclusive. Results: At our institution, with a total 8 cases with ruptured IIA, 4 patients were treated endovascularly and 2 by surgical bypass. For the systematic review, we included 12 non-comparative studies with a total of 547 patients with IIA. Median percentage of ruptured IIA was at least 65.2%, cases that required intervention was 23.7% for surgical cases, and 50% for endovascular cases. The overall median percentage of complications was 5.3%. Conclusions: This study highlights a single Canadian tertiary centre experience in the management of IIA and compares it to the global trends of the last 10 years in a systematic review.

Background: Intracranial hypertension secondary to shunt-failure is a feared complication requiring cross-sectional imaging for diagnosis. We compared dural sinus narrowing and ventriculomegaly as predictors of shunt-failure. Methods: 60 head MRIs and 60 MR venographies of hydrocephalus patients age 0-18 years (n=25) were analyzed. MRI studies were included when f/u clinical data combined with intra-operative findings proved shunt-failure (positive Gold standard) or when MRI was available when the child was well (negative Gold standard). The absence or presence of concerning hydrocephalus was diagnosed. On MRV, the major dural sinuses were independently analyzed with respect to >50% narrowing, suggesting compression by increased CSF pressure. Ventriculomegaly and significant dural sinus narrowing was correlated to the presence/absence of shunt failure as per Gold standard. Results: Sinus narrowing substantially correlated with proven shunt-failure (Cohen’s kappa test 0.635/p<=0.00001 as per Fisher exact test) while ventriculomegaly correlated poorly (0.258/p=0.0751). Sensitivity/specificity was 0.69/0.92 for sinus narrowing and 0.43/0.81 for ventriculomegaly. Conclusions: In this patient cohort, dural sinus narrowing more reliably predicted shunt-failure compared to ventriculomegaly.