Background: LC-FAOD may be missed in neuromuscular (NM) clinics due to its rarity and absence from common NM genetic panels. The Canadian Neuromuscular Disease Registry (CNDR) collects real-world patient data and includes a network of clinician-investigators. Our objective was to inform future registry work by evaluating diagnosis pathways for LC-FAOD patients and estimating the number followed at Canadian NM clinics. Methods: A questionnaire was developed with an expert committee and circulated to 111 CNDR-affiliated NM neurologists. Results: 12 neurologists in 5 provinces, primarily adult-treating (n=8) completed the survey (10.8% response rate). Eleven (91.7%) practiced for >10 years. Agreement trends existed between definition of, and tests to evaluate, rhabdomyolysis. Four clinics routinely follow LC-FAOD patients. In the last 1-2 years, respondents diagnosed approximately 91 patients with LC-FAOD (mean=7.5 per clinic). 83.3% never received continuing education on LC-FAOD, though 75% indicated interest in expert-led webinars. Further data will be presented. Conclusions: Low sample size limits conclusions about LC-FAOD clinical trends. Results suggest LC-FAOD may be under-diagnosed or not routinely followed by NM specialists, limiting viability of an LC-FAOD registry. Practitioners may be interested in LC-FAOD-specific education. Future work could include collaboration with metabolic geneticists on education initiatives to raise awareness and improve care for these patients.

Background: Carpal tunnel syndrome (CTS) is less common in children but can be associated with significant disability. Pediatric CTS can be associated with an underlying disorder most commonly storage disorders including mucopolysaccharidoses (MPS). We report a patient with bilateral severe CTS secondary to Weill-Marchesani Syndrome (WMS). Methods: A retrospective chart review was completed. Results: A five-year-old female presented with a three-year history of bilateral thumb weakness and insensate digits two and three. Nerve conduction studies (NCS) revealed severe bilateral CTS. She underwent bilateral carpal tunnel release (CTR). Unfortunately, post-operative NCS was unchanged. Ultrasound showed significant median nerve compression with flexor tendon thickening. Metabolic investigations showed no evidence of a storage disorder. Trio whole exome sequencing showed two de novo likely pathogenic variants in ADAMTS10: c.1174delC, p.H392TfsX9 and a deletion of exons 3-8. Her exam was also noted to show bilateral camptodactyly and brachydactyly, and bilateral cataracts characteristic of WMS. Conclusions: Identifying the etiology of CTS is important for management and prognosis. WMS is a genetic connective tissue disorder that can cause brachydactyly and abnormal tendon thickening, which can have implications on surgical outcomes. Awareness of this diagnosis prior to surgery would allow for better patient counseling and management decisions.

Background: The use of patient reported and functional outcome measures in routine practice enhances shared decision making and supports patient-centred care. This study compared the perspectives of Chronic Inflammatory Neuropathy (CIN) patients and providers regarding their experience using an outcome measure panel. Methods: A one year study was conducted to evaluate a nine measure outcome set in routine clinical practice for CIN. The panel included patient-reported outcome measures (e.g., I-RODS and EQ-5D-5L) and functional measures (e.g., grip strength). At the conclusion of the study, participants and providers completed an online questionnaire on their experience. Results: 25 patients and five providers completed the questionnaire. Both patients and providers reported benefit in tracking disease progression, supporting treatment-related decisions, and broadening views of health. Both groups agreed patient involvement in care was enhanced. Preference for specific measures, frequency, and data presentation differed. Providers emphasized integration into electronic medical records and streamlining processes. 100% of providers and 80% of patients wanted to continue completing outcome measures. Conclusions: CIN patients and providers recognize the value of integrating outcome measures into routine care. To effectively implement these measures in clinical settings, it is important to understand the patient and provider perspective and prevent unnecessary burdens to ensure sustainability of use.

Background: Charcot Marie Tooth disease is a polygenic disorder with cannonical features of distal amyotrophy, acrohypesthesia, and tight tendoachilles of either axonal (type 2) or demeylinating (type 1) varieties. Type 1 CMT patients are required to possess conduction slowing of a sufficient degree to qualify as demyelinating. Presented is a middle-aged man with an unremarkable neurologic exam and normal electrophysiology. Methods: Standard electrophysiological techniques were employed to obtain the nerve conduction data (Natus Nicolet EDX AT2; Middleton, WI, USA). Repeated next generation sequencing and deletion/duplication analyses were performed. Results: The nerve conduction studies showed no evidence of demyelination in the upper or lower extremeties. The duplication error was confirmed with repeat testing. The heterozygous PMP22 gene duplication encompassed the entire coding sequence involving exons 1-5. Conclusions: CMT1A accounts for the vast majority of dysmyelinating hereditary neuropathies. Phenotypic variability is well described. Presentations include (a) classic conduction slowing, (b) intermediate slowing, (c) conduction block, (d) HNPP-like, (e) absent CMAPs, and (f) normal NCSs in young infants. This is the first case of a neurologically intact adult with CMT1A. Cryptogenic genetic modifier-effect(s) are posited as a possible explanation of the lack of penetrance. Identifying the nature of this modification may prove instructive for future therapies.

Background: Chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) is a rare, acquired polyneuropathy, especially in children, affecting the peripheral nervous system. It most commonly presents in a symmetric, proximal and distal, sensorimotor fashion. Immunosuppression and immunomanipulation are treatment modalities. We present a case of a 14 year old male with severe progressive CIDP who became refractory to steroid and IVIg but responded to Rituximab. Methods: Case presentation: A 14-year-old male with a history of asymmetric quadriparesis was diagnosed with CIDP. He had an initial partial response to IVIG and prednisone but then rapidly became refractory to even weekly IVIG and prednisone. Rituximab was therefore started. Results: Within 12 weeks his strength improved from quadriplegia to walker-assisted gait. By 22 weeks he achieved independent ambulation. His JAMAR hand grip increased from 0 to 28 kg. His worst recordable median conduction velocity (CV) improved from a nadir (MRC 0/5) of 14% of normal to 52% at full recovery (MRC 5/5). Conclusions: This case highlights several important clinical points. Dramatic improvement is possible in cases of quadriplegic CIDP. Strength recovery is not linearly related to CV recovery. There appears to be a role for polytherapy.

Background: Late onset Pompe disease (LOPD), rare autosomal recessive lysosomal storage disease, resulting from mutation in alpha glucosidase enzyme (GAA) can present even in 6th decade of life. Slowly progressive, subtle, limb girdle pattern of weakness (LGPW), with auxiliary features such as ptosis, enlarged tongue, axial rigidity, facial diplegia, variable degree of respiratory weakness is not uncommon. Hypertrophic and electrical cardiac abnormalities are well described in LOPD. Methods: We present a case of 67-year-old male presenting with proximal weakness, subtle ptosis, bilateral quadriceps and shoulder girdle atrophy, and left toe numbness. PMHx: CABG, NSTEMI. Statin use. FMHx: noncontributory. Results: EMG: L5 radiculopathy, with unexpected myopathic units in hip/pelvic/ shoulder girdle muscles with active denervation and muscle irritability. CK, CRP, SPEP, ANA, LFTs, HMG-CoA reductase: normal. GAA enzymatic activity=0.96µmol/L/hr (low), genetics: pathogenic variants in GAA gene: c.-32-13T>G and c.1194+3G>C. ECHO: severe diastolic dysfunction, restrictive left ventricular filling. PFTs: normal. Diagnosed with LOPD, started on therapy. Conclusions: LOPD remains a differential for LGPW especially in older patient population with history of cardiopulmonary features. Age-appropriate conconminant pathologies may confound the diagnostic process.Symptoms may preceed diagnosis for years.GAA enzymatic activity followed by genetic testing remains readily available and can confirm diagnosis, preventing delay of approved therapy.

Background: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with only four approved treatments in North America - sodium phenylbutyrate (PB) and ursodoxicoltaurine (TURSO, also known as taurursodiol), riluzole, edaravone, and tofersen. Poor treatment adherence reduces clinical effectiveness which can adversely impact disease progression and mortality rates. Understanding barriers and adherence to treatment in clinical practice is essential to address these issues. Methods: A scoping review was conducted in PubMed, Medline, Embase, and Web of Science. Retained studies were, (1) published in English, (2) included adults with ALS, (3) explored treatment non-adherence and/or identified barriers associated with non-adherence in ALS in real world clinical practice, (4) focused on ≥1 of the four approved ALS medications, and (5) used a measurement of adherence. Observational studies, real-world data, and case reports were included. Quality assessment was performed. Results: The review illustrated several knowledge gaps, including limited data on the incidence of non-adherence to ALS treatment in clinical practice, a lack of understanding regarding barriers to treatment adherence in ALS, and an absence of studies outside of western societies. Conclusions: We demonstrate a dearth of real-world data on treatment adherence in ALS and highlight opportunities for advancing research into this important area.

Background: Neuroborreliosis affects approximately 10-15% of people with untreated Lyme disease and typically declares itself 2-18 weeks after infection. North American neuroborreliosis often manifests with cranial nerve palsy, meningitis, and/or radiculoneuritis. Methods: Here we describe a case of North American neuroborreliosis and also highlight some of the rare manifestations of systemic Lyme disease. A 65-year old male presented with a subacute history of progressive upper extremity weakness, neck pain, and headache. This occurred in the context of a recent tick exposure. Results: MRI of the brachial plexus, serology and CSF studies, and EMG/NCS were consistent with a diagnosis of polyradicular neuroborreliosis. However, whole body imaging identified some concerning features suggestive of lymphoma: specifically a large necrotic mediastinal lymph node and a number of vascular abnormalities. In light of these findings, the differential also included neurolymphomatosis and a PET scan was conducted. Reassuringly, there was no increase in FDG avidity in the distribution of his affected nerves. Moreover, his neurologic symptoms exhibited clinical improvement following treatment of his neuroborreliosis. Conclusions: This case provides an excellent example of the clinical features of neuroborreliosis, but more importantly also highlights some of the rarer potential manifestations, which warrant further investigation.

Background: We performed a network meta-analysis of randomized controlled trials to assess the comparative effectiveness of available pharmacological prophylaxis for migraines. Methods: We searched MEDLINE, EMBASE, Web of Science, Scopus, PsycINFO and Cochrane CENTRAL up to October 2023 for trials that: (1) enrolled adults diagnosed with chronic migraine, and (2) randomized them to any prophylactic medication vs. another medication or placebo. We performed a random-effects frequentist network meta-analysis for patient-important outcomes. Results: We included 193 randomized trials. Compared to placebo, CGRP monoclonal antibodies (mean difference [MD] -1.7, 95%CI: -1.1 to -2.2), injection of botulinum toxin (MD -1.8, 95%CI: -0.7 to -2.9), calcium channel blockers (MD -1.8, 95%CI: -0.5 to -3.0), beta-blockers (MD -1.4, 95%CI: -0.2 to -2.6), and anticonvulsants (MD -1.1, 95%CI: -0.4 to -1.8) were among the most effective treatments in reducing average number of headache days per months. Anticonvulsants (Risk Ratio [RR] 2.3, 95%CI: 1.8 to 3.0), calcium channel blockers (RR 1.8, 95% CI: 1.1 to 3.1), and tricyclic antidepressants (RR 2.3, 95% CI: 1.3 to 3.8) showed the highest risk of discontinuation due to adverse events. Conclusions: Our findings suggest that CGRP inhibitors, botulinum toxin, and beta-blockers may provide the greatest benefit, and tolerability, for reducing the frequency of migraine headaches.

Background: Spinal dermoid cysts are uncommon, benign tumours of ectodermal origin, often associated with spinal dysraphism. Malignant transformation of spinal dermoid cysts is an exceptionally rare entity, with transformation into carcinosarcoma not previously reported. Methods: Case report and literature review Results: A 41-year-old male presented with a recurrent lumbar intradural mass, 28 years after resection of a dermal sinus tract and associated dermoid cyst. Intraoperative appearance and subsequent pathology were again consistent with a dermoid cyst. The patient re-presented 2 weeks after surgery with diplopia and headache due to hydrocephalus, thought to be due to chemical meningitis. Following ventriculoperitoneal shunt implantation, the patient rapidly deteriorated with progressive neurologic deficits and widespread leptomeningeal enhancement. A repeat spinal leptomeningeal biopsy was pursued, which revealed malignant transformation of the dermoid cyst into invasive carcinosarcoma. Without curative treatment options, the patient was palliated and died 85 days after admission. Conclusions: Malignant transformation of spinal dermoid cysts should be considered in the differential diagnosis of patients with dermoid cysts and progressive leptomeningeal enhancement. False negatives can occur with initial tumour pathology and repeat sampling may be warranted for diagnostic clarity. To the authors knowledge, this is the first report of a spinal dermoid cyst with malignant transformation into carcinosarcoma.

Background: Care for patients with compression neuropathies (carpal tunnel syndrome, ulnar neuropathy) is often fragmented, uncoordinated, and slow. Patients go through multiple steps (neurology consultation, nerve testing, ultrasound, splints, injection, surgical opinion, surgery) with waits between each step. We used a Value-Based Health Care (VBHC) model to develop a multidisciplinary clinic with a novel care pathway. Methods: A Shared Care initiative supported the development of an Integrated Practice Unit (IPU). Key multidisciplinary team members were identified. Participants attended a curated three part VBHC workshop. Process mapping enabled identification of efficiencies. Results: 14 team members participated in the workshops. Condition specific outcome measures were identified (Boston CTS measure, 10-point touch, MRC strength and pain scale) and will be collected longitudinally. Criteria and clinical pathways were developed for mild, moderate, and severe carpal tunnel syndrome. Resource materials for patients and providers were developed. Conclusions: A VBHC framework supported development of a novel clinic for compression neuropathy. Responsibility for the full cycle of care rests with the IPU. Systematically tracking functional outcome measures enables quality improvement. By streamlining the patient journey and substantially reducing wait times between steps, the new care pathway reduces complexity and improve outcomes. Evaluation of impact if this new clinical model is ongoing.

Background: OSCE-GPT (https://learnmedicine.ca/) is an AI-based app that integrates history, physical exam, and relevant components for case guidance across medical disciplines to help trainees improve clinical skills. With global users across 60+ countries, this preliminary quality improvement study gathers user feedback on neurology and otolaryngology cases. Methods: A survey was distributed to users at the University of Ottawa and Cumming School of Medicine. Participants provided insights on the app’s use, perceived benefits, and suggested improvements. Results: Using 5-point Likert scales, 13 respondents, 9 of which evaluated an otolaryngology case, rated the overall usefulness of the learning tool 4.57± 0.51 (1=very poor, 5=very good), with a score of 4.00±0.65 relative to other teaching methods, such as didactic lectures or grand rounds (1=much worse, 5=much better). Users noted realistic interactions and self-paced learning as beneficial factors. Areas for improvement included a more fluid transition between physical exams and history, geographic variations in cases, and the addition of elements such as non-verbal patient cues or emotional. Conclusions: This study demonstrates utility of OSCE-GPT for medical trainees, particularly for otolaryngology and neurology cases. As cases continue to be added, feedback will be implemented to further improve user experience.

Background: Neurofibromatosis 1 is a multisystem, neurocutaneous disorder with a predisposition for various malignancies. There is no established care pathway or multidisciplinary clinic for adult patients with NF1 in British Columbia (BC). Patients may miss timely screening or therapeutic interventions. The development of new therapies for NF1 highlights the urgency for coordinated care. Methods: A review of existing programs and guidelines was conducted. The estimated population with NF1 in BC was determined. A working group consisting of neuromuscular neurology, pediatric neuro-oncology, adult neuro-oncology, and medical genetics identified gaps in care. Results: Approximately 2200 adult individuals with NF1 are estimated to live in BC. A three-prong approach to address identified gaps was developed: A quarterly multidisciplinary NF Case Conference was initiated. The initial session was attended by 18 providers. Focus groups for patients and providers to enhance understanding of both perspectives are being conducted. Informed by the focus groups, an NF1 Care Pathway for BC will be developed. Conclusions: Advances in treatment for NF1 prompted the formation of the BC NF Working Group to develop a strategy to improve longitudinal, multidisciplinary care. The development of a care pathway, with patient input, will improve care coordination and access to care.

Background: The Endoscopic Transphenoidal Approach to the Skull Base (ETSS) is now used internationally for a wide variety of pathologies ranging from CSF leaks to complex brain tumours. Methods: Case illustrations. Historical review of the evolution of ETSS with a focus on Canada’s contributions. Results: Canadians have been major contributors in the development and advancement of surgery of the skull base, particularly through endoscopic means. These will be highlighted with particular emphasis of those of Hardy, Cusimano, Kassam, Gentili, and others. Conclusions: Canada has been and continues to be an international leader in development and treatment of patients with skull base lesions, particularly those with lesions of the skull base amenable to ETSS.

Background: Pilocytic astrocytoma and other circumscribed low-grade brain tumors can exhibit spontaneous enhancement changes despite stable size and clinical status. We aimed to describe this phenomenon in adults. Methods: We performed a retrospective review of our MRI database (2011-2021) to identify cases with enhancement changes in otherwise stable tumors. We searched for reports containing: “pilocytic”, “pilomyxoid”, “RGNT”, “rosette”, “glioneuronal”, “DNET”, and “dysembryoplastic”. Exclusion criteria included WHO grade 3/4 tumors, patients <19 years, equivocal diagnostic findings, and no serial MRIs. We reviewed 238 patients. Results: We identified 12 adult patients with the desired phenomenon: 6 pilocytic astrocytoma, 1 pilomyxoid astrocytoma, 2 rosette-forming glioneuronal tumor, 1 unverified low-grade glioma, and 2 cases without biopsy. Seven were untreated, while five were residual or recurrent tumors. Six showed a pattern of new/increasing and subsequent decreasing/disappearing enhancement over 1-4 years. One exhibited spontaneous regression of enhancement over 1 year. Five showed repeating cycles of increasing and decreasing enhancement over longer monitoring periods of 7-15 years, with mean duration of increasing enhancement prior to decline of 21.4 months (SD 5.9). Conclusions: Spontaneous contrast enhancement fluctuation in adult pilocytic astrocytoma and other circumscribed low-grade brain tumors can occur, and on its own should not be misconstrued as evidence of tumor progression/regression.

Background: Interest in artificial intelligence (AI) and machine learning (ML) has been growing in neuroradiology, but there is limited knowledge on how this interest has manifested into research and the field’s trends, challenges, and future directions. Methods: The American Journal of Neuroradiology was queried for original research articles published since inception (Jan. 1, 1980) to Sept. 19, 2022 that contained any of the following key terms: “machine learning”, “artificial intelligence”, or “radiomics”. Articles were screened, categorized into Statistical Modelling (Type 1), AI/ML Development (Type 2), or End-user Application (Type 3) and then bibliometrically analyzed. Results: A total of 124 articles were identified with 85% being non-integration focused (Type 1 n = 41, Type 2 n = 65) and the remaining (n = 18) being Type 3. The total number of articles published grew two-fold in the last five years, with Type 2 articles mainly driving this growth. While most (66%) Type 2 articles were led by a radiologist with 55% possessing a postgraduate degree, a minority of Type 2 articles addressed bias (15%) and explainability (20%). Conclusions: The results of this study highlight areas for improvement but also strengths that stakeholders can consider when promoting the shift towards integrating practical AI/ML solutions in neuroradiology.

Background: The aim of our educational exhibit is to review the anatomy and pathology encountered and often overlooked of the excretory lacrimal apparatus from the lacrimal sac to the nasal fossa. Methods: We will provide an anatomical review of the various structures easily identifiable on CT and MRI and suggestions of the best imaging protocols to be used. Results: The lacrimal apparatus includes the various structures related to the production and flow of tears. In this educational exhibit we will focus on the excretory apparatus from the lacrimal sac to the nasal fossa. We will present various pathologies affecting the excretory lacrimal apparatus with attention to the specific features of each condition to facilitate an appropriate differential diagnosis. We will emphasize specific anatomical/imaging findings to help the diagnosis and propose a standardized reporting system for the Neuroradiologist and useful to the ENT surgeon. Conclusions: This educational exhibit offers a unique opportunity to review the anatomy and pathology of sometimes overlooked or forgotten structures which are however always included in our CT and MRI studies.

Background: Radiofrequency ablation (RFA) is a minimally-invasive procedure that has been used to treat temporal lobe epilepsy (TLE), however its long-term efficacy is unknown. We aim to characterize the long-term outcomes of patients from the original series by Parrent and Blume (1999). Methods: Consecutive patients who underwent stereotactic RFA for TLE were retrospectively reviewed. Demographics, procedural details, and seizure outcomes until last follow-up were abstracted. Seizure-freedom after initial RFA treatment was estimated with Kaplan-Meier analysis. Results: 27 patients underwent RFA from 1994 to 2002. There were 14 female (52%) patients. 24 (89%) had mesial temporal sclerosis. Mean age at time of RFA was 33.1 years (range 12-45 years). 17 (63%) patients underwent left-sided RFA. 15 (56%) patients had further interventions: 4 (15%) underwent only repeat RFA, 1 (4%) had repeat RFA and anterior temporal lobectomy (ATL), and 10 (37%) underwent subsequent ATL only. Mean follow-up was 9.0 years (range 0.5-22.7 years). At last follow-up, 16 (59%) patients were seizure-free: 5 (19%) received one RFA treatment and 11 (41%) underwent additional procedures. Conclusions: Based on the original series describing the technique, stereotactic RFA for TLE is a safe, minimally-invasive procedure. The role of stereotactic RFA in the treatment of TLE remains to be determined.

Background: Bi-directional brain interfacing (closed loop DBS) is a modern focus of neuroengineering research. Most current clinical systems are open loop, allowing one way communication from the IPG battery to the brain. Bi-directional systems allow both stimulation and recording of neural activity (local field potential, LFP). The system algorithm can measure known pathologic LFPs to guide change in stimulation. However, recording LFPs from the brain encounters electrical artifact from the heart. Reducing artifact is imperative to accurate measurement of neural activity. Artifact will cause the bi-directional system to miscalculate stimulation parameters. This project evaluated reduction of artifact by moving the IPG further away from the heart in a device implanted into the skull. Methods: LFP data from ongoing clinical trials was collected and analysed for artifact using open source code. Anatomic targets include STN, PPN, CMT, and PAG. Results: Cardiac artifact is reduced in skull mounted DBS as shown by power spectral density of LFPs in each region. Conclusions: This project shows the importance of surgical placement of DBS sensing devices to reduce cardiac artifact in bi-directional brain interfacing. This has important engineering and surgical design implications for safety and performance as the field of closed loop DBS transitions from research to clinical settings.

Background: Success of deep brain stimulation (DBS) in Parkinson’s disease (PD) relies on time-consuming trial-and-error testing of stimulation settings. Here, we prospectively compared an fMRI-based stimulation optimization algorithm with >1 year of standard-of-care (SoC) programming in a double-blind, crossover, non-inferiority trial. Methods: Twenty-seven PD-DBS patients were prospectively enrolled for fMRI using a 30-sec DBS-ON/OFF cycling paradigm. Optimal settings were identified using our published classification algorithm. Subjects then underwent >1 year of SoC programming. Clinical improvement was assessed, after an overnight medication washout period, under SoC and fMRI-determined stimulation conditions. A predefined non-inferiority margin was -5 points on the Unified Parkinson’s Disease Rating Scale (UPDRSIII). Results: UPDRSIII improved from 45.3 (SD=14.6) at baseline to 24.9 (SD=10.9) and 24.1 (SD=10.9) during SoC and fMRI-determined stimulation, respectively. The mean difference in scores was 0.8 (SD=8.5; 95% CI -4.5 to 6.2). The non-inferiority margin was not contained within the 95% confidence interval, establishing non-inferiority (p=0.013). Conclusions: This is the first prospective evaluation of an algorithm able to suggest stimulation parameters solely from the fMRI response to stimulation. It suggests equivalent outcomes may be achieved in 3 hours of fMRI scanning immediately after surgery compared to SoC requiring 6 or more in-person clinic visits throughout >1 year.