Background: Hyperosmotic hyperglycemic nonketotic state (HHS) is associated with myriad neurological complications such as seizures. Methods: We report a case presenting with visual hallucinations due to occipital lobe epilepsy. Results: A 67-year old woman with chronic hypertension, hyperlipidemia and diabetes mellitus non-compliant to medication presented with a 10-day history of recurrent visual phenomena in the left visual field. She described stationery multi-coloured flashing lights which decreased in intensity, brightness and size after 3 minutes. She was alert and conscious during attacks. There was no limb jerking. Neurological examination was normal with no visual field defect. Capillary glucose was 28.1 mmol/L, Hba1c 9% and B-hydroxybutyrate < 0.1. She was treated with actrapid 8 units, glipizide 5 mg BD and empagliflozin 12.5 mg OM. Interictal electroencephalogram was normal with no epileptiform activity. Brain magnetic resonance imaging revealed restricted diffusion in the right occipital cortex with corresponding cortical thickening and increased FLAIR signal with subtle hypodensity on GRE sequence. Her visual symptoms improved dramatically with hydration and diabetic control. She was treated with a short course of keppra. Conclusions: Visual hallucinations are an uncommon but well recognised and fully reversible complication of HHS. Clinicians should not forget HHS in the workup of occipital lobe epilepsy.

Background: Stroke therapies remain an area of ongoing research. Gene therapies offer a novel approach to repair tissue damage, particularly NeuroD1-mediated astrocyte-to-neuron conversion, which regenerates functional neurons after ischemic injury. Here, we applied NeuroD1 therapy in a non-human primates (NHPs) stroke model to evaluate its effects on corticospinal tract (CST) recovery and motor performance. Methods: Eight NHPs underwent middle cerebral artery occlusion (MCAO). Fourteen days later, six animals received intracranial NeuroD1 treatment (three high-dose, three low-dose), while two received a control solution. Neurological and functional performance were assessed daily. MRI scans were performed at baseline and at 7, 30, 90, 120, and 240 days post-MCAO, with the bilateral CST reconstructed at each time point. All procedures followed Canadian Council of Animal Care guidelines and were approved by Queen’s University’s Animal Use Subcommittee. Results: We found that NHPs receiving the control solution exhibited poorer motor recovery and minimal CST reconstruction. In contrast, those treated with a low dose of NeuroD1 demonstrated motor and functional recovery along with CST reconstruction. Notably, animals receiving the higher dose showed the most significant overall recovery including a greater CST integrity. Conclusions: NeuroD1 treatment promotes white matter tract restoration and facilitates motor recovery following stroke.

Background: Non-pharmacological interventions that promote self-management are crucial for individuals with mild cognitive impairment (MCI.) Mindfulness training has shown promise but is often not tailored to MCI. Methods: In 2021, the Neil and Susan Manning Cognitive Health Initiative (CHI) - a collaboration between the Vancouver Island Health Authority, Universities of BC and Victoria, and the Victoria Hospitals Foundation - partnered with the BC Association for Living Mindfully (BCALM) to develop a specialized mindfulness program for MCI, based on Mindfulness-Based Stress Reduction (MBSR). This multi-phase initiative aimed to enhance self-management, address the lack of outpatient services for MCI in Victoria, and contribute to the evidence base for mindfulness interventions. Results: Phase 1 assessed the BCALM program’s suitability for MCI; feedback included suggestions to simplify content and meditations. Phase 2 piloted an adapted version, with an 8-week program consisting of weekly sessions. Participants, recruited from the Seniors Outpatient Clinic in Victoria, completed pre- and post-program surveys; results showed over 90% of participants reported improved memory and coping, and 80% managed memory-related challenges better. Conclusions: Now in Phase 3, the MCI program is being transitioned into regular BCALM curriculum, with plans for a clinical trial comparing it to traditional psychoeducational approaches.

Background: Epilepsy has significant implications to quality of life (QOL) beyond the seizures themselves. While research has investigated QOL among people with epilepsy (PwE) from around the globe, minimal research exists on QOL among PwE living in Canada. Methods: People with drug-resistant epilepsy admitted to the Epilepsy Monitoring Unit in London, Ontario completed the “Quality of Life in Neurological Disorders” questionnaire (Neuro-QOL), a scale evaluating 13 QOL domains. We assessed objective cognition using a battery called Creyos. Results: Participants (N=42) scored significantly worse than the reference populations on the anxiety, satisfaction with social roles and activities, and cognitive functioning Neuro-QOL domains (p<.05). Scores on these domains, as well as depression and positive affect/well-being were unrelated to age (mean=39.3 years, SD=16.9), sex (28 females), education level, epilepsy duration, and age of epilepsy onset (p>.05). There were no correlations between scores on these Neuro-QOL domains and Creyos performance in short-term memory, reasoning, and verbal processing (p>.05). Conclusions: PwE living in Canada experience negative QOL in anxiety, social satisfaction, and subjective cognition, unrelated to the clinical factors or cognitive domains investigated. More attention is needed in Canadian clinical care and research to assess and address these affected attributes of QOL for all PwE.

Background: This study aimed to describe the technical characteristics and clinical efficacy of intracranial-to-intracranial (IC-IC) bypass for the treatment of complex intracranial aneurysms. Methods: We retrospectively reviewed all patients with aneurysms who underwent a preplanned combination of surgical or endovascular treatment and IC-IC bypass at our institution between January 2006 and September 2023. IC-IC bypass techniques included four strategies: type A (end-to-end reanastomosis), type B (end-to-side reimplantation), type C (in situ side-to-side anastomosis), and type D (IC-IC bypass with a graft vessel). Results: We performed the type A strategy on five patients (50.0%), type B on one (10.0%), type C on one (10.0%), and type D on three (30.0%). During a mean period of 68.3 months, good clinical outcomes (modified Rankin Scale score, 0-2) were observed in all patients. Follow-up angiography demonstrated complete aneurysmal obliteration in all patients and good bypass patency in nine of ten patients (90.0%). Conclusions: The treatment of complex aneurysms remains a challenge with conventional surgical or endovascular treatments. IC-IC bypass surgery is a useful technique, associated with favorable clinical outcomes, for treating complex aneurysms.

Background: Neurosurgery is a long and arduous training program, and the demands of neurosurgical training have led to resident burnout prevalence ranging from 11-67%, attrition, and suicide. We aimed to assess whether implementation of a weekly self-assessment tool with optional psychological counselling improves neurosurgical resident quality of life. Methods: We performed a one year prospective cohort study including 14 Calgary (intervention group) and 12 Toronto/Winnipeg residents (control group). Calgary residents utilized a mobile application (“HONE”) weekly, and all residents responded to questionnaires at baseline, midpoint and endpoint: EQ-5D-5L, Maslach Burnout Inventory (MBI), and Mayo Clinic Well-being Index (WBI). Between and within group results were compared using two-tailed t-tests. Results: Pooled baseline scores were comparable to population norms, with increased mean MBI depersonalization scores (10.28 versus 7.12, p=0.033), and more WBI “at risk” scores compared to normative data. There were no baseline differences between cohorts. EQ-5D-5L, MBI, and WBI scores were comparable between and within cohorts at all three time points. Three intervention group residents accessed psychological counselling, totalling ten sessions. Conclusions: Weekly use of the HONE application did not impact resident quality of life, although multiple residents displayed help-seeking behaviours. HONE provided tangible data for the program director to track trends in team well-being.

Background: Degenerative Cervical Myelopathy (DCM) is a progressive condition causing cervical spinal cord injury. Disease severity is commonly assessed using the modified Japanese Orthopedic Association (mJOA) score, yet clinical guidelines do not integrate pain—a key symptom—in evaluations. This meta-analysis examines the relationship between pain scores and quality of life outcomes (QOL) in surgical DCM patients. Methods: A comprehensive literature search using MEDLINE, Web of Science, and Embase identified 73 studies. Data regarding pain scores (VAS/NRS) and QOL outcomes (SF-12, SF-36) were extracted by 2 independent reviewers and all conflicts were resolved by the senior author. The number of patients analyzed in the studies included was 929. Results: Meta-regression identified no significant relationship between pain and SF-36 preoperatively but found a significant negative correlation at 3 months (r = -0.67, p<0.05), 6 months (r = -0.65, p<0.05), 1 year (-0.63, p<0.05), and 2 years (r = -0.62, p<0.05). Conclusions: Our results indicate a strong relationship between postoperative pain and QOL among patients with DCM. Surgeons and care teams should prioritize optimal pain management postoperatively for patients with DCM.

Background: Ocular point-of-care ultrasound (POCUS) may be a clinically useful method to evaluate shunt dysfunction for children with hydrocephalus in the emergency department (ED). We assessed whether a change in optic nerve sheath diameter (ONSD) from prior asymptomatic baseline is associated with shunt failure. Methods: This prospective single center cohort study included asymptomatic shunted children (age 0-18 years). Baseline ocular POCUS was performed in the outpatient neurosurgery clinic; a second POCUS was performed if the patient subsequently presented to the ED with symptoms of shunt failure. Shunt failure was defined by intraoperative confirmation of inadequate CSF flow through the shunt within 96 hours from ED presentation. Results: The primary outcome of intra-operatively confirmed shunt failure occurred in 14/76 (18%) ED patient presentations. ΔONSD in patients with and without shunt failure was 0.89mm and 0.16mm respectively; the mean difference was 0.73mm (95%CI: 0.34-1.12), p=0.0012. The area under the receiver operating characteristic curve was 0.86, with an optimal cutoff of ≥+0.4mm, corresponding to sensitivity of 0.93, specificity of 0.73, PPV of 0.43, NPV of 0.98. Conclusions: ΔONSD was strongly associated with shunt failure. We found ΔONSD of <+0.4 in symptomatic children with CSF shunts may identify a population that had low likelihood of true shunt failure.

Background: Meningiomas exhibit considerable heterogeneity. We previously identified four distinct molecular groups (immunogenic, NF2-wildtype, hypermetabolic, proliferative) which address much of this heterogeneity. Despite their utility, the stochasticity of clustering methods and the requirement of multi-omics data limits the potential for classifying cases in the clinical setting. Methods: Using an international cohort of 1698 meningiomas, we constructed and validated a machine learning-based molecular classifier using DNA methylation alone. Original and newly-predicted molecular groups were compared using DNA methylation, RNA sequencing, whole exome sequencing, and clinical outcomes. Results: Group-specific outcomes in the validation cohort were nearly identical to those originally described, with median PFS of 7.4 (4.9-Inf) years in hypermetabolic tumors and 2.5 (2.3-5.3) years in proliferative tumors (not reached in the other groups). Predicted NF2-wildtype cases had no NF2 mutations, and 51.4% had others mutations previously described in this group. RNA pathway analysis revealed upregulation of immune-related pathways in the immunogenic group, metabolic pathways in the hypermetabolic group and cell-cycle programs in the proliferative group. Bulk deconvolution similarly revealed enrichment of macrophages in immunogenic tumours and neoplastic cells in hypermetabolic/proliferative tumours. Conclusions: Our DNA methylation-based classifier faithfully recapitulates the biology and outcomes of the original molecular groups allowing for their widespread clinical implementation.

Until recently, much work on the process and impact of compensated emancipation in the British Empire tended to exclude the Cape Colony, instead focusing on Britain and the Caribbean. This analysis of the Cape Town agents who acted as intermediaries in the business of compensation reintegrates the Cape Colony into these discussions. Using Thomson, Watson & Co.’s account book, this article details how the Cape Town firm used its networks within the colony and in London to profit from the business of compensation. The firm handled over 800 claims from Cape Colony principals, purchased them on its own and others’ accounts, and remitted them to several associates in London for collection. This article contributes a new perspective to the growing literature on the process and impact of compensated emancipation and raises questions about the role of slavery and emancipation in the development of commercial and financial capitalism in South Africa.

Discussions of sample-based music are traditionally single-authored, despite the frequency of multi-genre content found within this repertoire. This article builds a case for a new approach for future analyses, justified by highlighting repertoire that embeds samples from different genres, times, and cultures and that calls upon a variety of disciplinary expertise to attend to these disparate contents. Multi-voice commentary is an approach that includes insider voices to speak to the content of sample-based music, building a reception network that runs counter to single authorial modes, broadening the narrative around sample-based music and its lineage. Certain sample-based works are most in need of this new approach, based on situations of ‘sampling up’, ‘down’, or ‘sideways’, tendencies developed from Nader’s concept of ‘studying up’ and Walser’s writings on ‘appropriations from below’. Theoretical ideas from Fish and Barthes are also brought into this discussion to further the case for a multiplicity of readings.

Background: Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease process that represents a significant health shock for thousands of patients each year. Return to work outcomes and associated factors require evaluation to counsel patients and identify domains on which to focus clinical efforts. Methods: A systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines was performed using MEDLINE, EMBASE and Cochrane databases from inception to February 2024. Proportion of patients returning to work was collected from included studies. Odds ratios were pooled from studies evaluating the association between pre-rupture demographic variables, post-rupture clinical variables and return to work following aSAH. Results: Literature search yielded 3861 studies, of which 40 studies were included in the final analysis for a total of 6888 patients. On average, 55% (SD 17%) of all patients returned to work after an aSAH. Female sex (male sex OR 1.75), high grade aSAH on presentation (OR 0.30), and need for permanent CSF diversion (OR 0.50) are significantly associated with unemployment after aSAH. Conclusions: Female sex, high grade presentation, and permanent CSF diversion are associated with unemployment after aSAH. About half of all patients that experience aSAH return to work.

Background: Studies have found similar rates of functional independence for men and women after endovascular thrombectomy (EVT). Less is known regarding EVT-related procedural complications and symptomatic intracerebral hemorrhage (sICH) between sexes. Methods: Using the OPTIMISE registry including data from 20 comprehensive stroke centers across Canada between 1/1/2018 and 12/31/2022, we performed a retrospective descriptive analysis of patients divided between men and women. Hemorrhagic transformation on follow-up imaging with associated clinical deterioration was required to define sICH. Results: 3631 patients were included (1778 men and 1853 women) for analysis. Female patients were older (71.8±14.6 vs 68.0±13.1 years, p<0.001). There were no differences in sICH rates (2.5% men vs. 2% women, p= 0.388}. Procedural complication rates were not different between men and women (5.8 vs 5.6% p=0.76): dissection {26 (1.5%) vs. 30 (1.6%), p=0.804}, perforation {11 (0.6%) vs. 7 (0.4%), p=0.426}, embolization {25 (1.4%) vs. 25 (1.3%), p=0.996} and arterial access complications {45 (2.5%) vs. 43 (2.3%), p=0.761}. Conclusions: In this large multicentre registry of stroke patients undergoing EVT, men and women had similarly low and reassuring rates of sICH and procedural complications. This complements previous data showing similar functional outcomes for men and women after EVT.

Background: Endonasal endoscopic odontoidectomy (EEO) is a well-established method for treating symptomatic ventral compression at the cranio-cervical junction (CCJ). This study aims to review the clinical outcomes of patients undergoing EEO, focusing on clinical presentation, progression, and prognostic factors. Methods: We retrospectively analyzed data from patients who underwent EEO between October 2001 and October 2023. Information was collected on demographics, indications, reconstruction techniques, complications, fusion requirements, readmission rates, and outcomes. Results: Fifteen patients were included, with 60% classified as ASA class III. The majority presented with myelopathy (80%). Indications for surgery included basilar invagination, Chiari malformation, and rheumatoid arthritis. The mean blood loss was 317 ml. No perioperative lumbar drains were used, and 26.7% of patients had intraoperative CSF leaks, though no postoperative leaks were noted. A pedicled nasal flap was required in 66.7% of cases. Fourteen patients needed occipitocervical fusion, and six were readmitted within 30 days due to bulbar deficits. At the last follow-up, 86.6% of patients experienced symptom improvement. A significant association was found between decompression extent and symptomatic improvement (p=0.003). Conclusions: EEO is a safe and effective method for CCJ decompression, often accompanied by posterior cervical stabilization, with most patients showing symptomatic improvement and a low complication rate.

Background: Telemedicine evaluation for treatment of acute stroke patients with IV thrombolysis has been shown to be beneficial. Its usefulness for the evaluation of patients transferred from a primary stroke centre (PSC) to a comprehensive stroke centre (CSC) for endovascular thrombectomy (EVT) is less well defined. Methods: We retrospectively analyzed the Canadian OPTIMISE registry which included data from 20 comprehensive stroke centers across Canada between January 1, 2018, and December 31, 2022 to compare treatment metrics and early outcomes between two groups: patients evaluated by telemedicine (TM) and patients evaluated in person (non-TM) at the PSC prior to CSC transfer. Results: We included 3317 patients who were transferred from a PSC to a CSC for: 888 TM and 2429 non-TM. There were no major differences in baseline characteristics, including intravenous thrombolysis administration, though the TM group included more men. TM patients had longer onset-to-puncture times (441 vs 403 minutes, p<0.001) and higher symptomatic intracerebral hemorrhage (sICH) rates (7.4% vs 3.7%, p<0.001), but CSC door-to-puncture times and successful recanalization rates did not differ. Conclusions: Patients transferred to a CSC for EVT first evaluated by TM had similar characteristics to those evaluated in person at the PSC, but longer onset-to-puncture times and higher sICH rates.

Background: Surgical robotics can minimize the discrepancy between surgical preoperative plan and postoperative execution. This work explores the performance of a supervisory-control architecture robot (8i Robotics) for autonomous pedicle instrumentation in both an open and MIS workflow in a poricne model, as well as guidance accuracy in humans. Methods: 11 porcine subjects (7 open, 4 minimally invasive) had clinical grading assessment of pedicle screw placement. 3 of the open cohort had detailed precision analysis. Post-operative CT assessed screw location. Euclidean error was calculated at screw head and screw tip and confidence ellipses generated. In two human patients, guidance accuracy was compared to existing neuro-navigation. Results: All screws where GRS A. There was no clinical difference between clinical assessment of MIS vs Open workflow. Mean tip and head Euclidean error where 2.47+/-1.25mm and 2.25+/-1.25mm respectively. Guidance was successfully obtained in both human cases. Conclusions: 100% of screws obtained satisfactory clinical grading. This demonstrates the capability of a supervisory controlled robotic pedicle screw insertion robot in both open and minimally invasive workflow. Furthermore, initial guidance was feasible in living human patients with comparable agreement to current navigation. This work demonstrates exciting promise for the future of autonomous surgical robotics.

Background: Meningiomas are the most common intracranial extra-axial lesion. Reports of meningioma regression exist, often in the context of known hormonal or vascular fluctuations, though very few describe complete resolution. Though rare, extra-axial mimics such as lymphoma and chloroma may also spontaneously regress. Methods: Electronic medical records were used to access patient information in accordance with our local ethics review board. Results: A 29-year-old male presenting with new onset seizures was found to have a 22.7 x 26.6 mm left temporal extra-axial lesion, radiologically consistent with meningioma. Due to wait times and patient preference, repeat pre-operative imaging was not available prior to surgical resection 13 months later, though an interim CT had confirmed persistence of the tumour’s size 1 month after diagnosis. Decision was made to proceed with resection; however, intraoperatively, no lesion was identified. Post-operative imaging demonstrated complete disappearance of the lesion, and follow-up imaging has shown no recurrence. Conclusions: This case highlights the possibility of spontaneous resolution of extra-axial lesions and emphasizes the importance of serial imaging prior to resection.

Background: This study aimed to identify risk factors for postoperative cerebrospinal fluid (CSF) leaks and assess their outcomes following endoscopic endonasal approach (EEA) for resection of skull base tumors. Methods: A retrospective review was conducted of patients who underwent EEA for resection of intradural pathology between October 2001 and October 2023. Data on demographics, approach type, reconstruction technique, tumor pathology, complications and outcomes were analyzed. Results: A total of 542 patients were included, with 80.1% undergoing surgery for sellar or suprasellar pathology. Lumbar drains were used in 14.9%, and dural sealants in 57.7%. Forty patients (7.3%) developed postoperative CSF leaks, with the highest rate in sellar or suprasellar lesions (5.9%). CSF leaks were associated with longer hospital stays (p < 0.001), higher 30-day readmission rates (p < 0.001), increased sepsis risk (p = 0.021), and higher rates of diabetes insipidus (p < 0.001). Lumbar drains increased the incidence of CSF leaks (p = 0.021), while nasoseptal flap reconstruction reduced leak rates (p = 0.0015). Higher BMI and intraoperative CSF leaks were also significant risk factors (p = 0.001) Conclusions: CSF leaks are associated with increased complications and extended hospital stays, highlighting the need for vigilant intraoperative monitoring and targeted strategies.

This paper discusses the development of synthetic cohomology in Homotopy Type Theory (HoTT), as well as its computer formalisation. The objectives of this paper are (1) to generalise previous work on integral cohomology in HoTT by the current authors and Brunerie (2022) to cohomology with arbitrary coefficients and (2) to provide the mathematical details of, as well as extend, results underpinning the computer formalisation of cohomology rings by the current authors and Lamiaux (2023). With respect to objective (1), we provide new direct definitions of the cohomology group operations and of the cup product, which, just as in the previous work by the current authors and Brunerie (2022), enable significant simplifications of many earlier proofs in synthetic cohomology theory. In particular, the new definition of the cup product allows us to give the first complete formalisation of the axioms needed to turn the cohomology groups into a graded commutative ring. We also establish that this cohomology theory satisfies the HoTT formulation of the Eilenberg–Steenrod axioms for cohomology and study the classical Mayer–Vietoris and Gysin sequences. With respect to objective (2), we characterise the cohomology groups and rings of various spaces, including the spheres, torus, Klein bottle, real/complex projective planes, and infinite real projective space. All results have been formalised in Cubical Agda, and we obtain multiple new numbers, similar to the famous ‘Brunerie number’, which can be used as benchmarks for computational implementations of HoTT. Some of these numbers are infeasible to compute in Cubical Agda and hence provide new computational challenges and open problems which are much easier to define than the original Brunerie number.

In this paper, we study the following high-order elliptic equation involving the GJMS operator:

\begin{align*}\alpha P_{\mathbb{S}^n}v_{\alpha}+2Q_{g_{\mathbb{S}^n}}=2Q_{g_{\mathbb{S}^n}}e^{nv_{\alpha}}.\end{align*}

We establish that if α > 1 and $n\geq3$ or if $\alpha\in (1-\epsilon_0, 1)$ with $n=2m\geq4$, then $v_{\alpha}\equiv0$. As an application, we present a new proof of the classical Beckner inequality.