Faculty Bibliography

Familial dysautonomia (FD) is a rare genetic neurodevelopmental and neurodegenerative disorder. In addition to the autonomic and peripheral sensory neuropathies that challenge patient survival, one of the most debilitating symptoms affecting patients' quality of life is progressive blindness resulting from the steady loss of retinal ganglion cells (RGCs). Within the FD community, there is a concerted effort to develop treatments to prevent the loss of RGCs. However, the mechanisms underlying the death of RGCs are not well understood. To study the mechanisms underlying RGC death, Pax6-cre;Elp1^loxp/loxp male and female mice and postmortem retinal tissue from an FD patient were used to explore the neuronal and non-neuronal cellular pathology associated with the FD optic neuropathy. Neurons, astrocytes, microglia, Müller glia, and endothelial cells were investigated using a combination of histological analyses. We identified a novel disruption of cellular homeostasis and gliosis in the FD retina. Beginning shortly after birth and progressing with age, the FD retina is marked by astrogliosis and perturbations in microglia, which coincide with vascular remodeling. These changes begin before the onset of RGC death, suggesting alterations in the retinal neurovascular unit may contribute to and exacerbate RGC death. We reveal for the first time that the FD retina pathology includes reactive gliosis, increased microglial recruitment to the ganglion cell layer (GCL), disruptions in the deep and superficial vascular plexuses, and alterations in signaling pathways. These studies implicate the neurovascular unit as a disease-modifying target for therapeutic interventions in FD.

The development of disease-modifying therapies (DMTs) for neurological disorders is an important goal in modern neurology, and the associated challenges are similar in many chronic neurological conditions. Major advances have been made in the multiple sclerosis (MS) field, with a range of DMTs being approved for relapsing MS and the introduction of the first DMTs for progressive MS. By contrast, people with Parkinson disease (PD) still lack such treatment options, relying instead on decades-old therapeutic approaches that provide only symptomatic relief. To address this unmet need, an in-person symposium was held in Toronto, Canada, in November 2022 for international researchers and experts in MS and PD to discuss strategies for advancing DMT development. In this Roadmap article, we highlight discussions from the symposium, which focused on therapeutic targets and preclinical models, disease spectra and subclassifications, and clinical trial design and outcome measures. From these discussions, we propose areas for novel or deeper exploration in PD using lessons learned from therapeutic development in MS. In addition, we identify challenges common to the PD and MS fields that need to be addressed to further advance the discovery and development of effective DMTs.

BACKGROUND AND OBJECTIVES/UNASSIGNED:Previous research has demonstrated that simulation-based medical education (SBME) can improve neurology trainees' confidence, knowledge, and competence. However, a general needs assessment and review of current SBME used within neurology are needed to guide SBME curriculum development. The objective of this study was to describe the current use of SBME in resident education and to assess perceived barriers to expanding SBME interventions. METHODS/UNASSIGNED:We surveyed adult neurology residency program directors (PDs) listed in the Accreditation Council for Graduate Medical Education directory using a Qualtrics-based survey platform. Survey questions addressed current utilization of SBME and barriers to SBME growth. RESULTS/UNASSIGNED:Seventy-five PDs of 171 contactable PDs responded to our survey (response rate 44%). Of the respondents, 84% (64/75) report using SBME in their adult neurology residencies. Of those using SBME, 87% (55/64) programs create their own cases. Most programs use simulation to teach neurocritical care topics (63%) and vascular neurology (78%); few use simulation to teach outpatient topics and teleneurology. Among programs that use SBME, there was variability in the frequency of the SBME interventions and in the target trainee cohort. Among responding programs, most expressed interest in expanding SBME in their curriculum (69%, 52/64), but frequently cited lack of faculty protected time (55%), funding (35%), and resident availability (32%) as barriers to doing so. DISCUSSION/UNASSIGNED:Most responding programs use SBME. However, the frequency and target learner for SBME interventions varied between programs. Many programs wish to expand SBME at their institutions but are constrained by limited protected time and institutional financial support. We discuss potential solutions to the perceived barriers to SBME, including intra-institutional collaboration to advance SBME use and case diversity for learners and help innovate neurology medical education.

Sudden unexplained death in childhood (SUDC) is death of a child ≥ 12 months old that is unexplained after autopsy and detailed analyses. Among SUDC cases, ~ 30% have febrile seizure (FS) history, versus 2-5% in the general population. SUDC cases share features with sudden unexpected death in epilepsy (SUDEP) and sudden infant death syndrome (SIDS), in which brainstem autonomic dysfunction is implicated. To understand whether brainstem protein changes are associated with FS history in SUDC, we performed label-free quantitative mass spectrometry on microdissected midbrain dorsal raphe, medullary raphe, and the ventrolateral medulla (n = 8 SUDC-noFS, n = 11 SUDC-FS). Differential expression analysis between SUDC-FS and SUDC-noFS at p < 0.05 identified 178 altered proteins in dorsal raphe, 344 in medullary raphe, and 100 in the ventrolateral medulla. These proteins were most significantly associated with increased eukaryotic translation initiation (p = 3.09 × 10^-7, z = 1.00), eukaryotic translation elongation (p = 6.31 × 10^-49, z = 6.01), and coagulation system (p = 1.32 × 10^-5, z = 1.00). The medullary raphe had the strongest enrichment for altered signaling pathways, including with comparisons to three other brain regions previously analyzed (frontal cortex, hippocampal dentate gyrus, cornu ammonus). Immunofluorescent tissue analysis of serotonin receptors identified 2.1-fold increased 5HT2A in the medullary raphe of SUDC-FS (p = 0.025). Weighted gene correlation network analysis (WGCNA) of case history indicated that longer FS history duration significantly correlated with protein levels in the medullary raphe and ventrolateral medulla; the most significant gene ontology biological processes were decreased cellular respiration (p = 9.8 × 10^-5, corr = - 0.80) in medullary raphe and decreased synaptic vesicle cycle (p = 1.60 × 10^-7, corr = - 0.90) in the ventrolateral medulla. Overall, FS in SUDC was associated with more protein differences in the medullary raphe and was related with increased translation-related signaling pathways. Future studies should assess whether these changes result from FS or may in some way predispose to FS or SUDC.

Anxiety is highly prevalent in Alzheimer's disease (AD), correlating with cerebrospinal fluid/positron emission tomography biomarkers and disease progression. Relationships to plasma biomarkers are unclear. Herein, we compare levels of plasma biomarkers in research participants with and without anxiety at cognitively normal, mild cognitive impairment, and AD dementia stages. We observed significantly higher plasma tau/amyloid-β₄₂ ratio in AD participants with anxiety versus those without, but did not observe differences at other stages or plasma biomarkers. No such relationships were evident with depression. These results support a unique pathophysiological relationship between anxiety and AD that can be reflected in plasma biomarkers, suggestive of heightened neurodegeneration.

SMOC1 has emerged as one of the most significant and consistent new biomarkers of early Alzheimer's disease (AD). Recent studies show that SMOC1 is one of the earliest changing proteins in AD, with levels in the cerebrospinal fluid increasing many years before symptom onset. Despite this clear association with disease, little is known about the role of SMOC1 in AD or its function in the brain. Therefore, the aim of this study was to examine the distribution of SMOC1 in human AD brain tissue and to determine if SMOC1 influenced amyloid beta (Aβ) aggregation. The distribution of SMOC1 in human brain tissue was assessed in 3 brain regions (temporal cortex, hippocampus, and frontal cortex) using immunohistochemistry in a cohort of 73 cases encompassing advanced AD, mild cognitive impairment (MCI), preclinical AD, and cognitively normal controls. The Aβ- and phosphorylated tau-interaction with SMOC1 was assessed in control, MCI, and advanced AD human brain tissue using co-immunoprecipitation, and the influence of SMOC1 on Aβ aggregation kinetics was assessed using Thioflavin-T assays and electron microscopy. SMOC1 strongly colocalized with a subpopulation of amyloid plaques in AD (43.8 ± 2.4%), MCI (32.8 ± 5.4%), and preclinical AD (28.3 ± 6.4%). SMOC1 levels in the brain strongly correlated with plaque load, irrespective of disease stage. SMOC1 also colocalized with a subpopulation of phosphorylated tau aggregates in AD (9.6 ± 2.6%). Co-immunoprecipitation studies showed that SMOC1 strongly interacted with Aβ in human MCI and AD brain tissue and with phosphorylated tau in human AD brain tissue. Thioflavin-T aggregation assays showed that SMOC1 significantly delayed Aβ aggregation in a dose-dependent manner, and electron microscopy confirmed that the Aβ fibrils generated in the presence of SMOC1 had an altered morphology. Overall, our results emphasize the importance of SMOC1 in the onset and progression of AD and suggest that SMOC1 may influence pathology development in AD.

BACKGROUND:The randomized, phase 2 RENEW trial (NCT01721161) evaluated efficacy/safety of opicinumab (anti-LINGO-1) versus placebo in patients with first-episode unilateral acute optic neuritis (AON). Although no significant differences in the latency recovery of visual evoked potential (VEP) were observed between opicinumab and placebo groups in the intention to treat (ITT) population, the prespecified per-protocol (PP) population showed better recovery with opicinumab than with placebo. RENEWED (NCT02657915) was a one-visit, follow-up study 2 years after the last RENEW study visit (Week 32) designed to assess the long-term electrophysiological and clinical outcomes for participants previously enrolled and having received study treatment in RENEW. METHODS:In the original study (RENEW), participants (aged 18-55 years) with a first unilateral AON episode were enrolled ≤28 days from first symptom onset and after treatment with methylprednisolone 1 g/day intravenously for 3-5 days; these participants were randomized to receive opicinumab 100 mg/kg or placebo intravenously once every 4 weeks from baseline to Week 20, assessed up to Week 32. Participants who received ≥1 dose of opicinumab 100 mg/kg or placebo in RENEW were eligible for the RENEWED follow-up study. Participants enrolled in RENEWED at 2 years (with an additional up to 12-month window) after the last RENEW study visit (Week 32) in both ITT and PP populations. The primary endpoint was change in full-field VEP (FF-VEP) latency of the affected eye at RENEWED study visit versus baseline of the fellow eye in RENEW, comparing between participants who received opicinumab and placebo in RENEW. Clinical progression and severity of multiple sclerosis (MS) were assessed. A substudy evaluated latency recovery using multifocal VEP (mfVEP) as an exploratory endpoint. RESULTS:Of 82 RENEW participants, 52 (63.4 %; opicinumab n = 28, placebo n = 24) enrolled in and completed RENEWED. The adjusted mean (95 % CI) difference in FF-VEP latency delay between opicinumab and placebo groups was -6.0 (-14.6, 2.6) msec (p = 0.165) for the PP population and -4.5 (-12.6, 3.7) msec (p = 0.274) for the ITT population at the RENEWED study visit. Nominally significant improvement on mfVEP latency in the opicinumab group versus placebo was observed in participants of the mfVEP substudy (p = 0.009). In participants from the PP population without clinically definite MS (CDMS) at RENEW baseline,12 (55 %) in the opicinumab group and 12 (67 %) in the placebo group developed CDMS from enrollment in the RENEW study up to RENEWED Day 1; the estimated proportion of participants with CDMS at 2 years after the last study visit assessment in RENEW was lower when treated with opicinumab (0.50) than when treated with placebo (0.61) (hazard ratio p-value = 0.23). No benefit on visual acuity or other neurological functions was observed in the opicinumab group vs placebo in RENEWED. CONCLUSION/CONCLUSIONS:The numerically increased VEP latency recovery with opicinumab treatment in RENEWED was consistent with those observed in the parent study RENEW. However, the VEP latency and clinical data in RENEWED should be interpreted with caution, given the nature of the follow-up study, the small sample size and the limitation in study design.

BACKGROUND:Middle meningeal artery embolization (MMAE) has emerged as a promising therapy for chronic subdural hematomas (cSDHs). The efficacy of standalone MMAE compared with MMAE with concurrent surgery is largely unknown. METHODS:cSDH patients who underwent successful MMAE from 14 high volume centers with at least 30 days of follow-up were included. Clinical and radiographic variables were recorded and used to perform propensity score matching (PSM) of patients treated with standalone MMAE or MMAE with concurrent surgery. Multivariable logistic regression models were used for additional covariate adjustments. The primary outcome was recurrence requiring surgical rescue, and the secondary outcome was radiographic failure defined as <50% reduction of cSDH thickness. RESULTS:722 MMAE procedures in 588 cSDH patients were identified. After PSM, 230 MMAE procedures remained (115 in each group). Median age was 73 years, 22.6% of patients were receiving anticoagulation medication, and 47.9% had no preoperative functional disability. Median midline shift was 4 mm and cSDH thickness was 16 mm, representing modestly sized cSDHs. Standalone MMAE and MMAE with surgery resulted in similar rates of surgical rescue (7.8% vs 13.0%, respectively, P=0.28; adjusted OR (aOR 0.73 (95% CI 0.20 to 2.40), P=0.60) and radiographic failure (15.5% vs 13.7%, respectively, P=0.84; aOR 1.08 (95% CI 0.37 to 2.19), P=0.88) with a median follow-up duration of 105 days. These results were similar across subgroup analyses and follow-up durations. CONCLUSIONS:Standalone MMAE led to similar and durable clinical and radiographic outcomes as MMAE combined with surgery in select patients with moderately sized cSDHs and mild clinical disease.

BACKGROUND:Visual disability is a growing problem for many middle-aged and older adults. Conventional mobility aids, such as white canes and guide dogs, have notable limitations that have led to increasing interest in electronic travel aids (ETAs). Despite remarkable progress, current ETAs lack empirical evidence and realistic testing environments and often focus on the substitution or augmentation of a single sense. OBJECTIVE:This study aims to (1) establish a novel virtual reality (VR) environment to test the efficacy of ETAs in complex urban environments for a simulated visual impairment (VI) and (2) evaluate the impact of haptic and audio feedback, individually and combined, on navigation performance, movement behavior, and perception. Through this study, we aim to address gaps to advance the pragmatic development of assistive technologies (ATs) for persons with VI. METHODS:The VR platform was designed to resemble a subway station environment with the most common challenges faced by persons with VI during navigation. This environment was used to test our multisensory, AT-integrated VR platform among 72 healthy participants performing an obstacle avoidance task while experiencing symptoms of VI. Each participant performed the task 4 times: once with haptic feedback, once with audio feedback, once with both feedback types, and once without any feedback. Data analysis encompassed metrics such as completion time, head and body orientation, and trajectory length and smoothness. To evaluate the effectiveness and interaction of the 2 feedback modalities, we conducted a 2-way repeated measures ANOVA on continuous metrics and a Scheirer-Ray-Hare test on discrete ones. We also conducted a descriptive statistical analysis of participants' answers to a questionnaire, assessing their experience and preference for feedback modalities. RESULTS:Results from our study showed that haptic feedback significantly reduced collisions (P=.05) and the variability of the pitch angle of the head (P=.02). Audio feedback improved trajectory smoothness (P=.006) and mitigated the increase in the trajectory length from haptic feedback alone (P=.04). Participants reported a high level of engagement during the experiment (52/72, 72%) and found it interesting (42/72, 58%). However, when it came to feedback preferences, less than half of the participants (29/72, 40%) favored combined feedback modalities. This indicates that a majority preferred dedicated single modalities over combined ones. CONCLUSIONS:AT is crucial for individuals with VI; however, it often lacks user-centered design principles. Research should prioritize consumer-oriented methodologies, testing devices in a staged manner with progression toward more realistic, ecologically valid settings to ensure safety. Our multisensory, AT-integrated VR system takes a holistic approach, offering a first step toward enhancing users' spatial awareness, promoting safer mobility, and holds potential for applications in medical treatment, training, and rehabilitation. Technological advancements can further refine such devices, significantly improving independence and quality of life for those with VI.