A unique constellation of ocular structural changes and visual anomalies known as Spaceflight Associated Neuro-ocular Syndrome (SANS) affects 70 % of crew members after long-duration spaceflight. Current hypotheses regarding the etiology of SANS discuss cephalad fluid shifts and venous congestion, which are correlated with elevated intra-cranial pressure (ICP) and enlarged perivascular spaces (PVS). These PVS comprise the glymphatic system (GS), a recently discovered network of influx and efflux pathways for cerebrospinal fluid (CSF) and metabolites in the central nervous system (CNS). Both glymphatic clearance and traditionally understood CSF circulation are affected by sleep-wake cycles, displaying a significant increase in fluid flow during sleep. Natural sleep has been associated with a 60 % increase in interstitial space in animal studies, which likely enhances GS exchange and outflow. Corresponding studies in humans using contrast-enhanced MRI associate sleep with greater glymphatic clearance compared to wakefulness. The sleep problems of astronauts during long-duration spaceflight have been well documented, ranging from sleep disruption and decreased quality to insufficient sleep duration. With recent terrestrial studies providing evidence that sleep deprivation impairs molecular clearance from the human brain, it follows that similar glymphatic dysfunction may arise due to these conditions in astronauts. Thus, in addition to impairing crew member work performance on long-duration space missions, sleep deprivation may exert long-term neuro-ocular effects via decreased glymphatic efficiency and clearance. The adverse impact of the resulting cognitive and visual disturbances presents a major future performance risk to astronauts. This work discusses the existing body of literature regarding the connections between circadian disruption and glymphatic disruption as a potential contributing mechanism for the development of SANS. This association should receive focused attention in future research as a potential risk factor for SANS. In addition, interventions that enhance extraterrestrial sleep quality and duration may prove to be practical countermeasures for the prevention of this syndrome.

Stroke and traumatic brain injury (TBI) are a significant cause of death and disability nationwide. Both are considered public health concerns in rural communities in the state of South Carolina (SC), particularly affecting the African American population resulting in considerable morbidity, mortality, and economic burden. Stem cell therapy (SCT) has emerged as a potential intervention for both diseases with increasing research trials showing promising results. In this perspective article, the authors aim to discuss the current research in the field of SCT, the results of early phase trials, and the utilization of outcome measures and biomarkers of recovery. We searched PubMed from inception to December 2023 for articles on stem cell therapy in stroke and traumatic brain injury and its impact on rural communities, particularly in SC. Early phase trials of SCT in Stroke and Traumatic Brain injury yield promising safety profile and efficacy results, but the findings have not yet been consistently replicated. Early trials using mesenchymal stem cells for stroke survivors showed safety, feasibility, and improved functional outcomes using broad and domain-specific outcome measures. Neuroimaging markers of recovery such as Functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) combined with neuromodulation, although not widely used in SCT research, could represent a breakthrough when evaluating brain injury and its functional consequences. This article highlights the role of SCT as a promising intervention while addressing the underlying social determinants of health that affect therapeutic outcomes in relation to rural communities such as SC. It also addresses the challenges ethical concerns of stem cell sourcing, the high cost of autologous cell therapies, and the technical difficulties in ensuring transplanted cell survival and strategies to overcome barriers to clinical trial enrollment such as the ethical concerns of stem cell sourcing, the high cost of autologous cell therapies, and the technical difficulties in ensuring transplanted cell survival and equitable healthcare.

Objective: Several centers have implemented ambulances equipped with CT scanners and telemedicine capabilities, known as mobile stroke units (MSU), to expedite acute stroke care delivery in the pre-hospital setting. While MSUs have been shown to improve outcomes compared with standard emergency medical management, there are limitations to incorporating CT, including radiation exposure to emergency medical services personnel. Recently, a portable, low-field strength MRI (Swoop (R), Hyperfine, Inc., Guilford, CT) received FDA clearance for in-hospital use. Here, as proof-of-concept, we explore the possibility of performing MRI in a telemedicineequipped ambulance during active transport. Materials and Methods: In this initial technical demonstration, we imaged an MR phantom and a normal human volunteer using a standard stroke protocol during active ambulance transport. Results: Images of the MR phantom and volunteer were successfully obtained and were immediately available for viewing in the hospital PACS system. The images were deemed of diagnostic quality by the radiologist. Active motion correction maintained superior image quality despite vehicle and scanner motion. In-plane, low contrast resolution of greater than 4 x 4 mm was achieved. Average transmit speeds were calculated to be 3.54 Megabits/ second and upload data rates varied while in transit ranging from 8.54 to 4.13 Megabits/second. Conclusion: While MRI is not yet ready for clinical use in the MSU setting, our initial experience suggests potential technological feasible of this approach following future technical and MRI sequence development. Additional studies, incorporating patients, would be required to determine clinical feasibility.

With the advent of novel and emerging technologies, long duration spaceflight will become more common; along with it, an increase in its inherent health risks. However, health-related ethical issues arising during long-duration spaceflight remain poorly characterized, uncertain and unpredictable. Medical ethics is defined as a set of moral principles, beliefs and values that guides choices about medical care. This set of principles, founded in our sense of right and wrong, helps us make fair and just decisions. The paper conceptually and analytically investigates the ethical issues likely to arise from medical complications during spaceflight, mapping unfilled gaps of the current status quo. Furthermore, this paper explores broad ethical themes of autonomy, nonmaleficence, beneficence and justice, while also delving deeper into specific scenarios within each theme. The manuscript represents an up-to-date review of the available literature in the field of space medical ethics and recommends guiding ethical principles and a framework for their application to negotiate the resolution of complex ethical scenarios during long-duration spaceflight.

Objective: Neurology in spaceflight has a rich history going back to the original days of the Gemini missions in the 1950s. With increased interest from governmental, commercial, and non-governmental entities the need to further address the integration of neurology and aerospace medicine as a burgeoning discipline. In preparation for the new Artemis generation, researchers and clinicians are attempting to understand better how changes to the nervous system are potentially hazardous and may compromise mission success. Long-duration spaceflight is associated with orthopedic, cardiovascular, urinary, immunologic, hematologic and neurologic changes. We aim to discuss several neurologic conditions that have been observed in astronauts, as well as discuss symptoms/syndromes which are limited to the spaceflight environment. According to NASA risk stratification, understanding particular neurologic conditions is critical as humanity sets its sights on the Moon and beyond. These conditions include cognitive changes, space motion sickness, space headache, and a progressively worsening visual acuity called Spaceflight-Associated Neuro-Ocular Syndrome (SANS). As more individuals representative of the average health of the population undergoes the rigors of spaceflight, more anticipated and unanticipated neurologic complications will occur. Patients with additional cardiovascular and neurologic risk factors will face different physiologic challenges than previous career astronauts and pilots. Primarily, neurologists will serve a vital role by applying knowledge of the central nervous system learned in the terrestrial equivalent patient to understand neuro-physiologic responses to spaceflight. This presentation aims to bring attention to and introduce this new area of neurology to help shape the future of humanity in space. Background: N/A Design/Methods: N/A Results: N/A Conclusions: N/A Disclosure: Dr. Rosenberg has nothing to disclose. Donna Roberts has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Guerbet. Donna Roberts has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Guerbet. The institution of Donna Roberts has received research support from Guerbet. The institution of Donna Roberts has received research support from NASA. Dr. Grimberg has nothing to disclose. Dr. Edwards has received intellectual property interests from a discovery or technology relating to health care. Dr. Saway has nothing to disclose. Sami Al Kasab has nothing to disclose.

Importance:Spaceflight-associated neuro-ocular syndrome (SANS) occurs in 40% to 60% of National Aeronautics and Space Administration (NASA) International Space Station (ISS) astronauts who present postflight with ophthalmological findings and elevated intracranial pressure. The etiology of SANS is unknown; it is hypothesized that venous outflow congestion from the head and neck occurs because of microgravity, which is supported by the finding of internal jugular vein stagnant flow and thrombosis in some astronauts, but the impact on intracranial dural venous sinus structures remains unknown. Objectives:To clarify the potential risk of retrograde extension of clot intracranially among astronauts with internal jugular venous thrombosis by evaluating intracranial venous structures following spaceflight and to assess for any association between intracranial venous congestion and SANS. Design, Setting, and Participants:This retrospective cohort study of all NASA astronauts who had undergone magnetic resonance (MR) venography at the time of the study included quantitative and qualitative assessments of the intracranial venous system on preflight and postflight MR venograms. Data were collected a mean (SD) of 525.8 (187.5) days before spaceflight and 2.0 (1.5) days after return to Earth. A semiautomated segmentation of the venogram images was used, which was then compared with a neuroradiologist's assessment. Exposures:A mean (SD) 184.3 (66.0) days of ISS spaceflight missions. Main Outcomes and Measures:Dural venous sinus volumes before and after spaceflight. Results:A total of 12 astronauts (2 [16.67%] women; 10 [83.33%] men), with a mean (SD) age of 47.8 (5.8) years, were included. Overall, 4 astronauts (33.33%) met the diagnostic criteria for SANS. No dural venous sinus thrombosis was detected for any astronaut. Astronauts with SANS had significantly greater median (range) preflight to postflight increases in volume vs astronauts without SANS for all 3 venous sinus structures: superior sagittal sinus (13.40% [8.70% to 17.47%] vs -2.66% [-15.84% to 5.31%,]; P = .004), right transverse/sigmoid sinus (17.15% [7.63% to 30.08%] vs 0.77% [-14.98% to 15.12%]; P = .02), and left transverse/sigmoid sinus (9.40% [5.20% to 15.50%] vs -1.40% [-14.20% to 12.50%]; P = .03). There was a positive correlation between the neuroradiologist's evaluation and the semiautomated method for the superior sagittal sinus (rpb = 0.64; P = .02) and the right transverse/sigmoid sinus (rpb = 0.58; P = .050). Conclusions and Relevance:These findings, in conjunction with the growing body of evidence of abnormal blood flow dynamics during spaceflight, suggest an association between intracranial venous congestion and SANS. Thus, there is an implication that individuals with increased venous sinus compliance may be at increased risk of developing SANS. These findings should be confirmed in a larger astronaut population and may contribute to understanding disorders of intracranial venous outflow on Earth.