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Recent missions on board the International Space Station have revealed previously unreported physiological consequences of long duration space flight, particularly in eyesight, and in this Brief Dr. Seedhouse reviews the existing theories on what causes this degeneration and how long it will last. Notably, 60% of long-duration crews have reported subjective degradation in vision, a clear indication that further study is necessary before astronauts embark on even longer-term space missions. Decreased near-visual acuity was reported in 46% of ISS/Mir crewmembers, resulting in a change of up to 2 dioptres in their refractive correction. It is possible that ophthalmic changes have been present since the first days of spaceflight, but had been attributed to other causes; this approach to the issue as well as other hypotheses are all presented in full to give a broad foundation of the existing knowledge on the topic. The changes have occurred at various times during a mission with varying degrees of visual degradation. Some cases resolved on return to Earth, but several crewmembers have not regained pre-flight visual acuity, indicating the damage may be permanent. One explanation of the syndrome has been attributed to hyperopic shift due to aging, but onboard analysis techniques, including visual acuity assessments, retinal imagery, and ultrasound examination of the eye, has led to the acceptance of a wider syndrome. In addition to vision changes, studies have reported flattening of the globe, swelling of the optic disc (papilledema), choroidal folds in the retina, swelling of the optic nerve sheath, and visual field defects. It is widely hypothesized that this spectrum of symptoms may be explained by an elevation of intracranial pressure (ICP). Establishing the provenance of this medical problem, monitoring its occurrence and resolving the symptoms for future long term space missions is a key challenge for space medicine. With this book, readers have an entry point for understanding the full scope of the problem and its possible origins.
Fluid distribution during spaceflight and impact on brain and vision health is an emerging field of high-priority research in the NASA human space program. International Space Station astronauts have developed ocular refraction changes during prolonged spaceflight. Within this book, experts review current data related to fluid shifts during microgravity exposure and the impact of fluid shifts on astronaut health. This work also compares current astronaut health problems with Earth-based health conditions such as elevated intracranial pressure and glaucoma. Chapters include discussion of altered fluid distribution, including intracellular and extracellular fluid shifts, eye morphology and vision disturbances, and intraocular pressure. In addition, chapters will include a discussion of advanced non-invasive technologies to investigate the abovementioned fluid volume and pressure variables. As such, the book aims to bridge health professionals, researchers, and science professionals by a presentation of ophthalmology topics critical to future human space exploration, thus providing new perspectives to solve emerging brain and eye disease on Earth and in Space.
Prolonged microgravity exposure during long-duration spaceflight (LDSF) produces unusual physiologic and pathologic neuro-ophthalmic findings in astronauts. These microgravity-associated findings collectively define the Spaceflight Associated Neuro-ocular Syndrome (SANS). In this book, the editors compare and contrast prior published work on SANS by the National Aeronautics and Space Administration’s (NASA) Space Medicine Operations Division with retrospective and prospective studies from other research groups. The book describes the possible mechanisms and potential etiologies for SANS, and provides an update and review on the clinical manifestations of SANS including: unilateral and bilateral optic disc edema, globe flattening, choroidal and retinal folds, hyperopic refractive error shifts, and focal areas of ischemic retina (i.e., cotton wool spots). The ocular imaging findings (e.g., retinal nerve fiber layer, optic disc, and choroidal changes on optical coherence tomography) of SANS is also described, including the intraorbital and intracranial findings on orbital ultrasound and magnetic resonance imaging. The knowledge gaps for in-flight and terrestrial human research including potential countermeasures for future stud is also explored, including reports on the in-flight and terrestrial human and animal research being investigated by NASA and its partners to study SANS both prospectively and longitudinally and in preparation for future long duration manned missions to space including the moon, the asteroid belt, or Mars. We think this is a unique topic and hope that NASA and its research partners continue to study SANS in preparation for future longer duration manned space missions. Written in an easy-to-read manner, the book adopts a translational approach and explores the science and the clinical manifestations of Space flight associated neuro-ocular syndrome. It is also multi-disciplinary and suitable for both clinicians and researchers in ophthalmology, neurology, and aerospace medicine interested in SANS SANS is a unique space flight disorder that has no terrestrial equivalent. The book involves contributions from international experts across multiple disciplines to tackle the problem of SANS Summarizes and reviews the current findings of SANS, including possible mechanisms and potential etiologies, clinical manifestations, current reports on the in-flight and terrestrial human and animal research, and ocular imaging findings
"Fluid distribution during spaceflight and impact on brain and vision health is an emerging field of high-priority research in the NASA human space program. International Space Station astronauts have developed ocular refraction changes during prolonged spaceflight. Within this book, experts review current data related to fluid shifts during microgravity exposure and the impact of fluid shifts on astronaut health.This work also compares current astronaut health problems with Earth-based health conditions such as elevated intracranial pressure and glaucoma. Chapters include discussion of altered fluid distribution, including intracellular and extracellular fluid shifts, eye morphology and vision disturbances, and intraocular pressure. In addition, chapters will include a discussion of advanced non-invasive technologies to investigate the abovementioned fluid volume and pressure variables.As such, the book aims to bridge health professionals, researchers, and science professionals by a presentation of ophthalmology topics critical to future human space exploration, thus providing new perspectives to solve emerging brain and eye disease on Earth and in Space"--
Safe Passage: Astronaut Care for Exploration Missions sets forth a vision for space medicine as it applies to deep space voyage. As space missions increase in duration from months to years and extend well beyond Earth's orbit, so will the attendant risks of working in these extreme and isolated environmental conditions. Hazards to astronaut health range from greater radiation exposure and loss of bone and muscle density to intensified psychological stress from living with others in a confined space. Going beyond the body of biomedical research, the report examines existing space medicine clinical and behavioral research and health care data and the policies attendant to them. It describes why not enough is known today about the dangers of prolonged travel to enable humans to venture into deep space in a safe and sane manner. The report makes a number of recommendations concerning NASA's structure for clinical and behavioral research, on the need for a comprehensive astronaut health care system and on an approach to communicating health and safety risks to astronauts, their families, and the public.
Eight cases identified, represent 23.5% of the 34 crewmembers flown on the ISS, with inflight visual changes and pre-to-postflight refractive changes. In some cases, the changes were transient while in others they are persistent with varying degrees of visual impairment. (1) Decreased intraocular pressure (IOP) postflight was observed in 3 cases. (2) Fundoscopic exams revealed postflight findings of choroidal folds in 4 cases, optic disc edema in 5 cases and presence of cotton wool spots in 3 cases. (3) Optical coherence tomography (OCT) confirmed findings of choroidal folds and disc edema and documented retinal nerve fiber layer thickening (4 cases). (4) Findings from MRI examinations showed posterior globe flattening (5 cases) and optic nerve sheath distension (6 cases). (5) Opening cerebrospinal fluid (CSF) pressure was elevated in 4 cases postflight reflecting raised intracranial pressure. While the etiology remains unknown, hypotheses speculate that venous insufficiency or hypertension in the brain caused by cephalad fluid shifts during spaceflight are possible mechanisms for ocular changes in astronauts.
Safe Passage: Astronaut Care for Exploration Missions sets forth a vision for space medicine as it applies to deep space voyage. As space missions increase in duration from months to years and extend well beyond Earth's orbit, so will the attendant risks of working in these extreme and isolated environmental conditions. Hazards to astronaut health range from greater radiation exposure and loss of bone and muscle density to intensified psychological stress from living with others in a confined space. Going beyond the body of biomedical research, the report examines existing space medicine clinical and behavioral research and health care data and the policies attendant to them. It describes why not enough is known today about the dangers of prolonged travel to enable humans to venture into deep space in a safe and sane manner. The report makes a number of recommendations concerning NASA's structure for clinical and behavioral research, on the need for a comprehensive astronaut health care system and on an approach to communicating health and safety risks to astronauts, their families, and the public.
This book introduces the latest advances relating to the pathophysiology, biophysics, monitoring and treatment of traumatic brain injury, hydrocephalus, and stroke presented at the 16th International Conference on Intracranial Pressure and Neuromonitoring (the "ICP Conference"), held in Cambridge, Massachusetts, in June 2016 in conjunction with the 6th Annual Meeting of the Cerebral Autoregulation Research Network. Additionally, the conference held special sessions on neurocritical care informatics and cerebrovascular autoregulation. The peer-reviewed papers included were written by leading experts in neurosurgery, neurointensive care, anesthesiology, physiology, clinical engineering, clinical informatics and mathematics who have made important contributions in this translational area of research, and their focus ranges from the latest research findings and developments to clinical trials and experimental studies. The book continues the proud tradition of publishing key work from the ICP Conferences and is a must-read for anyone wishing to stay abreast of recent advances in the field.
More than four decades have passed since a human first set foot on the Moon. Great strides have been made in our understanding of what is required to support an enduring human presence in space, as evidenced by progressively more advanced orbiting human outposts, culminating in the current International Space Station (ISS). However, of the more than 500 humans who have so far ventured into space, most have gone only as far as near-Earth orbit, and none have traveled beyond the orbit of the Moon. Achieving humans' further progress into the solar system had proved far more difficult than imagined in the heady days of the Apollo missions, but the potential rewards remain substantial. During its more than 50-year history, NASA's success in human space exploration has depended on the agency's ability to effectively address a wide range of biomedical, engineering, physical science, and related obstacles-an achievement made possible by NASA's strong and productive commitments to life and physical sciences research for human space exploration, and by its use of human space exploration infrastructures for scientific discovery. The Committee for the Decadal Survey of Biological and Physical Sciences acknowledges the many achievements of NASA, which are all the more remarkable given budgetary challenges and changing directions within the agency. In the past decade, however, a consequence of those challenges has been a life and physical sciences research program that was dramatically reduced in both scale and scope, with the result that the agency is poorly positioned to take full advantage of the scientific opportunities offered by the now fully equipped and staffed ISS laboratory, or to effectively pursue the scientific research needed to support the development of advanced human exploration capabilities. Although its review has left it deeply concerned about the current state of NASA's life and physical sciences research, the Committee for the Decadal Survey on Biological and Physical Sciences in Space is nevertheless convinced that a focused science and engineering program can achieve successes that will bring the space community, the U.S. public, and policymakers to an understanding that we are ready for the next significant phase of human space exploration. The goal of this report is to lay out steps and develop a forward-looking portfolio of research that will provide the basis for recapturing the excitement and value of human spaceflight-thereby enabling the U.S. space program to deliver on new exploration initiatives that serve the nation, excite the public, and place the United States again at the forefront of space exploration for the global good.
Our anatomy and physiology have been completely shaped by Earth's gravity. All body systems function in synergy with this unseen force. Yet, as we journey further and longer into space, our bodies must conform to a new reality, wherein gravity is absent or reduced, cosmic radiation threatens and our social and familial connections become distant. Into Space: A Journey of How Humans Adapt and Live in Microgravity gives an overview of some of the physiological, anatomical and cellular changes that occur in space and their effects on different body systems, such as the cardiovascular and musculoskeletal, and touches on cultural and psychosocial aspects of leaving behind family and the safety of Earth. It further addresses the complexity of manned space flights, showing how interdisciplinary this subject is and discussing the challenges that space physiologists, physicians and scientists must face as humans seek to conquer the final frontier.