Faculty Bibliography

A transient ischemic attack is an acute neurologic event caused by focal ischemia affecting the brain, eye, or spinal cord, resolving quickly without infarction on magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI). It is a tissue-based diagnosis, highlighting the need for prompt recognition and risk stratification. Evaluation in the emergency department includes detailed history, risk assessment, neurologic examination, and initial noncontrast computed tomography (CT) to rule out other conditions, with MRI DWI as the gold standard for confirming no infarction. Vascular imaging, echocardiography, electrocardiogram (ECG), and laboratories help identify underlying causes. Central retinal artery occlusion (CRAO) requires urgent diagnosis and ophthalmology consultation to prevent permanent vision loss.

BACKGROUND AND IMPORTANCE/BACKGROUND:Rhino-orbital cerebral mucormycosis (ROCM) is an aggressive fungal infection involving the paranasal sinuses, orbit, and intracranial cavity, with a propensity for vascular invasion. This can lead to complications such as internal carotid artery (ICA) thrombosis and occlusion, presenting major neurosurgical challenges. Although surgical debridement and antifungal therapy are the mainstays of treatment, cases with significant neurovascular involvement require specialized intervention. We report a case of ROCM with severe flow-limiting ICA stenosis treated by direct extracranial-intracranial bypass. CLINICAL PRESENTATION/METHODS:tA 65-year-old man with diabetes presented with progressive left-sided blindness and facial numbness. Imaging revealed a left orbital mass extending into the paranasal sinuses and intracranially. Empiric antifungal therapy was started. Pathology confirmed Rhizopus species. Despite extensive surgical debridement and antifungal therapy, the patient developed progressive severe cavernous ICA stenosis, leading to watershed territory strokes. To restore cerebral perfusion, protect from distal emboli, and prepare for potential aggressive debridement, a flow-replacing direct (superficial temporal artery-middle cerebral artery (M2)) bypass was performed, and the supraclinoid carotid was trapped. Intraoperative angiography confirmed robust flow through the bypass. The patient was discharged on antifungal therapy and aspirin. At 6-month follow-up, the patient was neurologically intact with an modified Rankin Scale score of 1. Computed tomography angiography and transcranioplasty Doppler ultrasonography confirmed good flow through the bypass. CONCLUSION/CONCLUSIONS:In addition to antifungal therapy and surgical debridement, superficial temporal artery-middle cerebral artery bypass can be a lifesaving intervention in the management of ROCM with severe cerebrovascular compromise. This case highlights the critical role of cranial bypass in preserving cerebral perfusion in patients with flow-limiting ROCM-associated ICA invasion.

BACKGROUND:Identifying early neuropathological changes in Alzheimer's disease (AD) is important for improving treatment efficacy. Among quantitative MRI measures, transverse relaxation time (T2) has been shown to reflect tissue microstructure relevant in aging and neurodegeneration; however, findings regarding T2 changes in both normal aging and AD have been inconsistent. The association between T2 and amyloid-beta (Aβ) accumulation, a hallmark of AD pathology, is also unclear, particularly in cognitively normal individuals who may be in preclinical stages of the disease. PURPOSE/OBJECTIVE:To investigate longitudinal hippocampal T2 changes in a cognitively normal cohort of older adults and their association with global Aβ accumulation. STUDY TYPE/METHODS:Retrospective, longitudinal. SUBJECTS/METHODS:56 cognitively normal adults between 55 and 90 years of age (17 males and 39 females). FIELD STRENGTH/SEQUENCE/UNASSIGNED:3 Tesla; multi-echo spin echo sequence for T2 mapping; 18F-florbetaben positron emission tomography for Aβ measurement. ASSESSMENT/RESULTS:Bilateral hippocampal T2 and volume were extracted to relate to Aβ PET measurements. To understand variations in AD risk, participants were separated into Aβ-high and Aβ-low subgroups using a predetermined threshold. STATISTICAL TESTS/METHODS:Linear mixed-effect models and general linear models were used. A p-value < 0.025 was considered significant to account for bilateral comparisons. RESULTS:Older age was associated with increased T2 in the bilateral hippocampus (left: β = 0.30, right: β = 0.25) and smaller hippocampal volume on the left (β = -0.12). In the Aβ-low subgroup, both longitudinal T2 increase rates (β = 0.65) in the left hippocampus and bilateral cross-sectional T2 (left: β = 0.64, right: β = 0.46) were positively correlated with Aβ PET, independent of hippocampal volume. DATA CONCLUSION/CONCLUSIONS:This study provided in vivo evidence linking hippocampal T2 to Aβ accumulation in cognitively normal aging individuals, suggesting that quantitative T2 may be sensitive to microstructural changes accompanying early Aβ pathology, such as neuroinflammation, demyelination, and reduced tissue integrity. EVIDENCE LEVEL/METHODS:3. TECHNICAL EFFICACY/UNASSIGNED:Stage 2.

We report a case of an 83-year-old female patient who presented with binocular diplopia associated with left periorbital pain. She was diagnosed with a left pupil-involving third nerve palsy initially believed to be either microvascular or aneurysmal. However, negative vascular neuroimaging and further serologic workup suggested the possibility of neurosyphilis. Her clinical course was significant for persistent periorbital pain and a new seventh nerve palsy, despite syphilis treatment, prompting repeat neuroimaging and lumbar puncture. This case highlights the importance of the clinical history, imaging, CSF studies, and repeated workup in distinguishing between infectious and noninfectious causes of cranial neuropathies.

It is well recognized that many pandemic viruses are associated with neurologic complications, most recently with COVID-19. After the outbreak of the COVID-19 pandemic, neurologic surveillance platforms were implemented to characterize the complications of COVID-19. Surveillance platforms are invaluable in providing timely data, informing clinical practice, and directing future research. Lessons learned from recent neurologic surveillance networks include the importance of global and cross-specialty collaboration. It is critical for future surveillance systems to consider these aspects, as it will also serve to improve representation of low and middle-income countries (LMICs) and communities. Trainees played a critical role in the success of neurologic surveillance networks; as frontline health care workers, they were able to provide timely data collection, and their fresh insights are important for future pandemic surveillance system development. In this article, we review the methods of recent neurologic surveillance networks and discuss their strengths and limitations. We explore the outlook for pandemic surveillance platforms and the crucial role global collaboration plays in ensuring that LMICs are represented. We review the role of trainees in pandemic surveillance networks and discuss how it is vital to encourage their continued involvement to ensure that, as future health care leaders, they are prepared to manage future pandemics effectively.

Language comprehension involves the prediction of upcoming linguistic units across multiple timescales. However, how this prediction process is hierarchically implemented in the human brain remains unclear. Combining natural language processing (NLP) and functional magnetic resonance imaging (fMRI) in a narrative comprehension task, we first applied the group-based general linear model (gGLM) to identify the neural underpinnings associated with anticipating upcoming words and sentences. Our results revealed a cortical hierarchy supporting linguistic prediction, extending from the superior temporal cortices to the default mode network (DMN). Next, we investigated how the word and sentence levels interact by testing two rival hypotheses: the continuous updating hypothesis posits that higher-level regions are updated continuously as inputs unfold over time, while the sparse updating hypothesis states that higher-level regions are updated only at the boundaries of their preferred timescales. Using computational modeling and autocorrelation analysis, we found that the sparse model outperformed the continuous model, with updating occurred at the sentence boundaries. Together, our results extend evidence for linguistic prediction to longer timescales and elucidate the neurocomputational mechanisms of hierarchical information updating in the human brain.

Polyaminopathies are a recently described family of rare genetic neurodevelopmental disorders. Polyaminopathies disrupt the biosynthesis of the primary polyamines: putrescine, spermidine, and spermine. Snyder-Robinson syndrome results from hemizygous loss-of-function variants in the spermine synthase (SMS) gene, resulting in decreased or complete loss of spermine synthase enzyme activity. Bachmann-Bupp syndrome results from heterozygous gain-of-function variants in the ornithine decarboxylase 1 (ODC1) gene, resulting in increased ornithine decarboxylase enzyme activity. Faundes-Banka syndrome results from heterozygous loss-of-function variants in the eukaryotic translation initiation factor 5A (EIF5A) gene, impairing eIF5A protein function. DHPS (deoxyhypusine synthase) deficiency is an autosomal recessive disease and results from bi-allelic hypomorphic variants in the deoxyhypusine synthase (DHPS) gene, which results in reduced deoxyhypusine synthase enzyme activity. Finally, DOHH (deoxyhypusine hydroxylase) disorder is an autosomal recessive disorder caused by bi-allelic loss-of-function variants in the deoxyhypusine hydroxylase (DOHH) gene, which causes decreased deoxyhypusine hydroxylase enzyme activity. Snyder-Robinson syndrome was first described in 1969, while the other four syndromes have only been identified in the past 7 years. A comprehensive phenotypic and genotypic description of these five syndromes is needed. We review the clinical and genetic features of these five polyaminopathies to create an inclusive clinical resource. A systematic keyword search strategy was used to identify all published cases in PubMed, Web of Science, and Scopus databases. The five known syndromes associated with the polyamine pathway share many similar clinical phenotypes, and yet patients with each syndrome present with distinctive syndromic features. This review will serve as a valuable resource for clinicians diagnosing and caring for patients with these rare polyaminopathies.

IMPORTANCE/UNASSIGNED:Neuroscientific, epidemiological, and electronic health record studies implicate herpes simplex virus (HSV) as potentially etiological for Alzheimer disease (AD). OBJECTIVE/UNASSIGNED:To compare the efficacy and adverse effects of valacyclovir vs placebo in participants with early symptomatic AD and HSV seropositivity (HSV-1 or HSV-2). DESIGN, SETTING, AND PARTICIPANTS/UNASSIGNED:This randomized clinical trial included adults with a clinical diagnosis of probable AD or a clinical diagnosis of mild cognitive impairment with positive biomarkers for AD, a positive serum antibody test (IgG or IgM) for HSV-1 or HSV-2, and a Mini-Mental State Examination score of 18 to 28. The trial was conducted at 3 US outpatient clinics specializing in memory disorders. Recruitment occurred from January 2018 to May 2022; the last follow-up occurred in September 2024. INTERVENTION/UNASSIGNED:Either 4 g/d of valacyclovir (n = 60) or matching placebo (n = 60). MAIN OUTCOMES AND MEASURES/UNASSIGNED:The primary outcome was least-squares mean (LSM) change at 78 weeks in the 11-item Alzheimer's Disease Assessment Scale Cognitive (ADAS-Cognitive) Subscale score (range, 0-70; higher scores indicate greater impairment). The secondary outcomes were LSM change in the Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) Scale score; LSM change in the 18F-florbetapir amyloid positron emission tomography (PET) standardized uptake value ratio (SUVR; higher scores indicate higher amyloid levels) for 6 brain regions (medial orbitofrontal, anterior cingulate, parietal lobe, posterior cingulate, temporal lobe, and precuneus); and LSM change in 18F-MK-6240 tau PET medial temporal SUVR (higher scores indicate higher tau levels) for 4 brain regions (amygdala, hippocampus, entorhinal, and parahippocampus). The frequency of adverse events was the safety outcome. RESULTS/UNASSIGNED:Of the 120 participants (mean age, 71.4 [SD, 8.6] years; 55% were female), 93 (77.5%) completed the trial. At 78 weeks, the LSM change in the 11-item ADAS-Cognitive Subscale score was 10.86 (95% CI, 8.80 to 12.91) in the valacyclovir group vs 6.92 (95% CI, 4.88 to 8.97) in the placebo group, indicating greater cognitive worsening with valacyclovir than placebo (between-group difference, 3.93 [95% CI, 1.03 to 6.83]; P = .01). The LSM change in the ADCS-ADL Scale score at 78 weeks was -13.78 (95% CI, -17.00 to -10.56) in the valacyclovir group vs -10.16 (95% CI, -13.37 to -6.96) in the placebo group (between-group difference, -3.62 [95% CI, -8.16 to 0.93]). At 78 weeks, the LSM change in the 18F-florbetapir amyloid PET SUVR was 0.03 (95% CI, -0.04 to 0.10) in the valacyclovir group vs 0.01 (95% CI, -0.06 to 0.08) in the placebo group (between-group difference, 0.02 [95% CI, -0.08 to 0.12]). The LSM change in the 18F-MK-6240 tau PET medial temporal SUVR at 78 weeks was 0.07 (95% CI, -0.06 to 0.19) in the valacyclovir group vs -0.04 (95% CI, -0.15 to 0.07) in the placebo group (between-group difference, 0.11 [95% CI, -0.06 to 0.28]). The most common adverse events were elevated serum creatinine level (5 participants [8.3%] in the valacyclovir group vs 2 participants [3.3%] in the placebo group) and COVID-19 infection (3 [5%] vs 2 [3.3%], respectively). CONCLUSIONS AND RELEVANCE/UNASSIGNED:Valacyclovir was not efficacious with cognitive worsening for the primary outcome and it is not recommended to treat individuals with early symptomatic AD and HSV seropositivity. TRIAL REGISTRATION/UNASSIGNED:ClinicalTrials.gov Identifier: NCT03282916.

While the physical manifestations of NF2-related schwannomatosis (NF2-SWN) have been well documented, there are a limited number of qualitative studies on health-related quality of life in NF2-SWN. The present study sought to explore the cumulative impact of symptoms, treatments, and healthcare on the quality of life of individuals with NF2-SWN. We interviewed 16 adolescent and adult patients with NF2-SWN enrolled in the INTUITT-NF2 clinical trial and 10 clinicians with NF2-SWN expertise from the United States, United Kingdom, and Australia. Analysis of patient and clinician interviews yielded five overall themes: (1) impacts on daily living, (2) impacts on life roles, (3) impacts on relationships and social integration, (4) impacts on psychological and emotional wellbeing, and (5) burden of treatment and healthcare. Multiple symptom areas contributed to impairments in quality of life across each theme. These findings reveal that quality of life in NF2-SWN is shaped not only by individual symptoms, but by their complex, cumulative impact-highlighting the urgent need for disease-specific tools and holistic care approaches that reflect the lived realities of patients across the lifespan.