NOTE: End date changed to 6/6/2021 per NSSC information (Ed., 11/9/20)

In the fall of 2021, we started a set of experiments in the lab to provide further baseline data by which to evaluate the upcoming flight data from this project. In these trials, subjects are evaluated for ocular alignment (OA) while standing on a hard floor, standing on foam, while seated, and while making head movements. This will help us evaluate the impact of postural demands on ocular alignment; we conjecture that the heightened demand while standing will call for a more precise compensation for any latent otolith asymmetry, causing a reduction in misalignment in that condition compared to seated. A new student team is now working on this project, Institutional Review Board (IRB) approvals and training have been completed, and experiments resumed in 2024. At this time approximately 25 subjects have been tested, and data analysis is continuing.

A portion of the protocol for this project was modified and extended for use as an educational demonstration at Space Center Houston. This enables collection of a large set of normative data (N=167 currently) with which to refine our analyses, and which can provide context for interpretation of results from astronauts. Initial analysis of these data were performed by medical student Nabila Ali for an epidemiology degree project and is now being prepared for publication. In parallel, biostatistics graduate student Alyssa Columbus is re-analyzing these data to look for relationships between the posture findings and the ocular-alignment (otolith asymmetry) findings.

This project also includes a component dedicated to data-integration of the other CIPHER (Complement of Integrated Protocols for Human Research) projects. While awaiting CIPHER flight data, we have been performing several preparatory activities so that we can be better prepared to organize and analyze that data:

1. An updated set of hypotheses (e.g., expected cross-study associations or correlations) was prepared, per the Statement of Work for this project, and provided to HRP in March 2024. In summary, some of the hypothesized cross-discipline connections include: •Vestibular and Cognitive. Disruption of the vestibular contribution to spatial orientation and memory might be a source of “space fog” and might be reflected in parallel changes in vestibular-mediated functions and cognitive tests. •Vestibulo-Autonomic interactions. These interactions impact post-flight orthostatic intolerance. Correlating inflight and postflight vestibular measures with postflight reports of presyncope or stumbling would provide information on this connection. •Bone and Vestibular. The vestibular gravity sensors rely on calcium carbonate, and calcium is the predominant constituent of bone. Thus, there might be parallel changes in ocular alignment (mediated by the otolith organs) and changes in bone structure. Connection to nutrition and food is also likely, as a source of calcium. •Fluid-shift effects related to the Eye and Sleep (diurnal phenomena). Sleep is essential in clearing neural waste products, which might be adversely impacted by alterations in fluid flow consequent to cephalid fluid shifting. Thus, there may be correlations between sleep quality and amount, ocular and other measures of fluid shift, and cognitive function dependent on neural integrity. •Stress markers and Cognition, Sleep, and Performance. It might not be possible to identify markers of stress that are not also indicators of other effects, but it might be possible to create a useful surrogate marker for stress that incorporates correlated measures of (for example) heart rate variability (HRV), sleep disturbance, cortisol, and other markers related to stress. Then, this stress indicator can be probed for correlations with other functions such as cognition and performance. Performance markers could include errors in routine tasks and calls to MCC for assistance. •Stress and Cardiac and Immune function. As noted, stress per se can be difficult to assess, but similar reasoning might be applied to look for correlations between stress and cardiovascular measures, and stress and immune function. •Vestibular and Teamwork and other Social interactions. Vestibular disorders can have an impact on motivation and interpersonal relations, which might impact behavioral and interpersonal issues such as relationships with others and the environment. •Circadian rhythms, Body temperature, and Sleep. Circadian rhythms would be derived from prevailing sleep cycle, and disruption inferred from alarms or slam shifts (metadata). Body temperature might not be available unless there is a surrogate measure such as a verbal report. •Sleep and Consolidation of learning/memory. Memory and motor learning are consolidated during sleep. It might be possible to determine if there are connections between sleep alterations and problems with memory or execution of motor skills. •Stress and Nutrition and Exercise. Nutrition and exercise countermeasures for physiological deconditioning, and are relatively easy to assess (biochemical profile, exercise logs). Stress is more difficult to assess and is multifactorial. Nevertheless, nutrition and exercise are known to have large effects on stress coping and so some effort should go into determining if there are measurable relationships.

2. A manuscript describing the scientific background and justification for CIPHER has been prepared by the PI. The final editing of this manuscript is still taking place.

3. Discussions began on how to acquire, archive, and curate the data that are expected to be provided to the PI by the other CIPHER investigators. After talking with several groups, it was determined that NLSP would be the right platform, provided a means for incorporating medical and metadata is developed, and the PI can have access to a work area on the platform.

4. Other discussions with ALSDA (Ames Life Sciences Data Archive) took place to identify datasets that are already available, that could help address some of the same questions as CIPHER.

5. Through discussions with Anand Narayanan, we have identified a set of data in OSDR (Rodent Research 9) that can be analyzed for relations between bone and ocular measures, as an initial investigation of cross-disciplinary effects of spaceflight. Since this project will analyze significant data before CIPHER, it can help provide guidance as to some relevant cross-discipline analysis methods. This is assisted by data science student Xiangyu Zhang and her faculty advisor Brian Caffo.

NOTE: End date changed to 6/6/2021 per NSSC information (Ed., 11/9/20)

This project was absorbed into the CIPHER (Complement of Integrated Protocols for Human Research) Vestibular Health IRB (Institutional Review Board) project as part of a broader re-scoping of CIPHER early in 2022. Online integrated consent briefings were supported, and a presentation was made at the online HRP (Human Research Program) Investigators Workshop in February 2023.

In the fall of 2023, Co-Investigator Amir Kheradmand, M.D. (a neurologist colleague at Johns Hopkins University/JHU) was added to the project at the behest of the NASA Johnson Space Center (JSC) Neurosciences Lab. He will assist JSC in the analysis of video data on ocular torsion.

In the fall of 2021, we started a set of experiments in the lab to provide further baseline data by which to evaluate the upcoming flight data from this project. In these trials, subjects are evaluated for ocular alignment (OA) while standing on a hard floor, standing on foam, while seated, and while making head movements. This will help us evaluate the impact of postural demands on ocular alignment; we conjecture that the heightened demand while standing will call for a more precise compensation for any latent otolith asymmetry, causing a reduction in misalignment in that condition compared to seated. Six subjects were tested on an early version of the protocol (30-40 planned in total), which was later modified to include additional conditions relevant to otolith effects on posture and locomotion. A new student team is now working on this project, IRB approvals and training have been completed, and experiments will resume in 2024.

A portion of the protocol for this project was modified and extended for use as an educational demonstration at Space Center Houston. This enables collection of a large set of normative data (N=167 currently) with which to refine our analyses, and which can provide context for interpretation of results from astronauts. Initial analysis of these data was performed by medical student Nabila Ali for an epidemiology degree project. This analysis so far shows a few things. Compliance was high in this volunteer population, with a 92% completion rate. Increasing age was significantly associated with increasing absolute median vertical (b = 0.002, p = 0.001) and torsional (b = 0.006, p = 0.04) ocular misalignment. Concussion history was associated with increased absolute median vertical (0.088, p = 0.09) and torsional (b = 0.280, p = 0.16) misalignment. Diabetes was associated with increased absolute torsional (b = 0.409, p = 0.06) misalignment. Smoking was significantly associated with decreased absolute torsional (b = -0.369, p = 0.03) misalignment. Final multivariate models for vertical misalignment included age and concussion history and torsional misalignment included age, concussion history, diabetes, and smoking. The connection to smoking is particularly interesting and suggests a connection to nicotine as a relevant parameter.

This project also includes a component dedicated to data-integration of the other CIPHER projects. While awaiting CIPHER flight data, we have been performing several preparatory activities so that we can be better prepared to organize and analyze that data:

1. An updated set of hypotheses (e.g., expected cross-study associations or correlations) and methods is being prepared, per the Statement of Work for this project. This will be provided to HRP in early 2024. This update will be based on the revised (final) schedule of data acquisition, and the revised (final) set of studies. It may require a reexamination of the text analytics previously performed (see below) and another set of such analyses based on the revised plan.

2. A manuscript describing the scientific background and justification for CIPHER has been prepared by the Principal Investigator (PI). Assistance in outlining the content was provided by Kristin Fabre of HRP, and further discussions on content were held with Cherie Oubre. This substantial report will require coordination with the journal where it is submitted, since its length (currently 6,666 words) pushes the limits for such a manuscript, and descriptions of each individual CIPHER study have not yet been incorporated. Discussion of this manuscript will take place at Investigators' Workshop (IWS) 2024.

3. Discussions have begun with several groups on how to acquire, archive, and curate the data that are expected to be provided to the PI by the other CIPHER investigators. This includes discussion with personnel from the ALSDA (Ames Life Sciences Data Archive) and their Open Science Data Repository (OSDR) project, which has created a set of templates for investigators to provide critical background data on each experiment as they upload data (nominally from the Space Biology program). Further conversations with LSDA identified a similar set of documents and guidelines that are in place for HRP data and LSDA. Work continues with LSDA to determine similarities and differences between these approaches, if ideas from the two approaches might be combined for the needs of CIPHER, and how examination of the HRP DAGs (Directed Acyclic Graphs) (see below) might inform updates to the data-ingestion templates (for example by identifying important but overlooked metadata).

4. Other discussions with LSDA continue in order to identify datasets that are already available, that could help address some of the same questions as CIPHER (i.e., are from the same or similar body systems), and would permit longitudinal (personalized) investigation. Potential datasets include published data from the early space program up through Skylab (when data were published in identifiable/attributable form), and LSDA data from STS (Space Transportation System) missions. While longitudinal (personalized) data are highly preferred (since that is what will be provided by CIPHER), pooled/population data might be useful in establishing bounds and broad cross-disciplinary correlations. (Graduate student Alyssa Columbus will work on this task with her academic advisors in biostatistics.)

5. Through discussions with Anand Narayanan, we have identified a Space Biology project (Effects of Simulated Microgravity and Partial Unloading on Organ Systems of the Body, PI: Michael Delp) that will acquire large amounts of multi-system data from animal models. Since this project will acquire and analyze significant data before CIPHER, it can help provide guidance as to some relevant cross-discipline analysis methods. The HRP DAGs (see below) can provide direction in the cross-fertilization of these two projects (Reynolds RJ, Scott RT, Turner RT, Iwaniec UT, Bouxsein ML, Sanders LM, Antonsen EL. Validating causal diagrams of human health risks for spaceflight: an example using bone data from rodents. Biomedicines. 2022 Sep 5;10(9):2187).

6. Plans for the next grant period also include:

a. Repetition of text analytics on the final configuration of CIPHER proposals, to identify common themes, methods, or approaches across studies. As before, this will involve examination of reference lists in each CIPHER proposal for citations to common authors, and Latent Dirichlet Allocation (LDA) to identify underlying concepts that might connect different proposals. This will inform the generation of new hypotheses (above).

b. Mapping of DAGs to the CIPHER studies, as another way to examine common areas across studies. DAGs have been created for all of the HRP Risks (Antonsen EL, et al. Directed Acyclic Graphs: A Tool for Understanding the NASA Human Spaceflight System Risks - NASA/TP-20220015708) and provide a common framework for discussing cross-disciplinary interactions and relations.

c. Development of a conceptual model that might identify astronaut subjects as “good” or “bad” adapters through broad general analyses of datasets, looking for groupings of parameters that can be ranked in terms of highly adaptive or less adaptive (ordinal rather than numerical analysis). (Proposed by undergraduate student Iuliia Dmitrieva.)

NOTE: End date changed to 6/6/2021 per NSSC information (Ed., 11/9/20)

In the fall of 2021, we started a set of experiments in the lab to provide further baseline data by which to evaluate the upcoming flight data from this project. In these trials, subjects are evaluated for ocular alignment (OA) while standing on a hard floor, standing on foam, while seated, and while making head movements. This will help us evaluate the impact of postural demands on ocular alignment; we conjecture that the heightened demand while standing will call for a more precise compensation for any latent otolith asymmetry, causing a reduction in misalignment in that condition compared to seated. Eight subjects have been tested to date on the entire protocol (12-15 planned in total), and analysis is ongoing. Initial observations show that performance is variable across subjects (as expected). Subjects unsurprisingly have the most difficulty when making pitching head movements. Otherwise, there are few notable differences between conditions.

A recent change was made to the OA software. Now, we collect information on the time that it takes a subject to perform each trial as a way to assess the level of confidence, motor control, and related factors.

A portion of the protocol for this project was modified and extended for use as an educational demonstration at Space Center Houston. This enables the collection of a large set of normative data (N=157 currently) with which to refine our analyses and which can provide context for the interpretation of results from astronauts (commercial and professional).

This project also includes a component dedicated to data-integration of the other CIPHER projects. While awaiting CIPHER flight data, we have been performing several preparatory activities so that we can be better prepared to organize and analyze that data: 1. Careful examination of the CIPHER complement to understand the measures and data that will be obtained, their modalities and form (numeric, imaging, etc.), and their sampling schedules. This will lead to an initial “binning” of the data: identification of those measures that can be considered to have been acquired at the same time point, taking into account the time course of change of the various physiological systems under study. This will then lead to an initial set of hypotheses and a statistical plan. 2. Identification of related datasets that are already available that could help address some of the same questions as CIPHER (i.e., are from the same or similar body systems), and would permit a longitudinal (personalized) investigation. The latter point is crucial since a key point of CIPHER integration is that data can be attributed to each individual astronaut test subject, allowing personalized cross-disciplinary study. Potential datasets under consideration include those from Mars 500, published data from the early space program up through Skylab (when data were published in identifiable/attributable form), and LSDA (Life Sciences Data Archive) data from STS (Space Transportation System) missions (under consultation with LSDA leadership). 3. Text analytics on the CIPHER proposals to identify common themes, methods, or approaches across studies. First, we examined reference lists in each CIPHER proposal for citations to common authors across proposals that might be unexpected (if proposals are in different disciplines) and might indicate unforeseen scientific connections. Second, networks were created to visualize how proposals are linked to each other through common terms relevant to HRP, such as its set of established hazards, risks, and environmental metadata. Third, Latent Dirichlet Allocation (LDA) was applied to identify underlying concepts that might connect different proposals. This investigation to date has provided some insights and few surprises but establishes an infrastructure by which to understand and interpret CIPHER within the larger set of space life-sciences concerns.

NOTE: End date changed to 6/6/2021 per NSSC information (Ed., 11/9/20)

This project was selected for flight (SFF), in modified form as noted below, in October 2020. Ocular-alignment assessment has been incorporated into the Vestibular Health Complement of Integrated Protocols for Human Research (CIPHER) project. Discussions continue with Scott Wood, who represents that project. The combined project uses a commercial head-mounted video system to measure eye movements. The original tablet-computer version of the test will be used for the first preflight test session as a backup; it can be used in place of the more complex head-mounted video system as a contingency.

Institutional Review Board (IRB) approval, in the form of a Reliance Agreement, was finalized between NASA Johnson Space Center (JSC) and Johns Hopkins University (JHU), for the tablet-computer version of the test. The JHU team will be added to the Vestibular Health IRB protocol, and the JSC team will be added to the JHU protocol. NASA IRB approval was obtained, including multinational consenting. In 2021, we supported online integrated consent briefings, as well as a combined Test Readiness Review (TRR), and finalized the Science Requirements Document. A presentation was made at the online HRP Investigators Workshop in February 2021.

While awaiting CIPHER flight opportunities, a portion of the protocol for this project was modified and extended for use as an educational demonstration at Space Center Houston (during which relevant baseline data will be obtained), and as a pre/post-flight test for commercial spaceflights (under separate Translational Research Institute for Space Health (TRISH) support).

Recently (fall 2021), we started a set of experiments in the lab, to provide further baseline data by which to evaluate the upcoming flight data from this project. In these trials, subjects will be evaluated for ocular alignment (OA) while standing on a hard floor, standing on foam, and while seated. This will help us evaluate the impact of postural demands on ocular alignment; we conjecture that the heightened demand while standing will call for a more precise compensation for any latent otolith asymmetry, causing a reduction in misalignment in that condition compared to seated.

NOTE: End date changed to 6/6/2021 per NSSC information (Ed., 11/9/20)

NASA is preparing to conduct International Space Station (ISS) missions of various durations, up to approximately one year. To take advantage of these missions, a standard set of measurements has been assembled to be carried out on all (or almost all) crew members on these missions. In addition, other measures may be added to better address the HRP risk areas. This project represents one such additional measure, which can be used to track low-level aspects of sensorimotor function not captured by the sensorimotor component of the standard measures.

This project is intended to provide information on binocular alignment as a measure of otolith asymmetry – more specifically as a measure of the central neural compensation for this asymmetry. This is a low-level sensorimotor function that has several attractive features: • It is easily and rapidly measured with minimal equipment, in flight and in the ground; • It provides complementary information to more functional posture and locomotion tests; • It has been validated in ongoing studies in patients with vestibular injuries and in parabolic flight; • It can provide an alternate means to assess underlying neurovestibular function which contributes to many sensorimotor responses. In this manner it might be a simpler alternative to posture and locomotion testing per se if it shown to provide similar actionable results.

We will use our device and methods to assess neurovestibular changes over time and determine (on a non-inferiority basis) specifically if there are concerns in going from six-month to one-year missions. We will also look for correlations with pre-flight and post-flight posture/locomotion testing.

Specific aims

1. Performance of otolith testing and refinement of procedures in an appropriate analog (isolation and confinement). Identification of any changes due solely to confinement and close quarters. [On hold – status TBD]

2. Crew training.

3. Performance in ISS flights of various durations.

4. Characterization of temporal trends, in part through the use of non-inferiority statistics on data as they become available.

5. Comparison of otolith measures with posture and locomotion measures.

Goals and questions to be addressed: 1. Characterization of temporal trends in central compensation for otolith asymmetry. Particular attention will be paid to any differences between six-month and one-year missions; 2. Understanding of the relationships between measures of otolith function and posture/locomotion performance

Relevance: A simple and rapid assessment of neural/neurovestibular function, as described here, will be a useful in-flight procedure to track changes over the course of a mission. Given the widespread connection of neural circuits and functions with other body functions, it is not inconceivable that neurovestibular effects as assessed here will likewise have implications for a wide variety of neural, cognitive, and performance aspects of crews in flight. Our testing provides an opportunity to assess a low-level neural system that is not under volitional control, is responsive to g-level alterations, and might be an indicator of broader and more functionally relevant effects.

Background: During the g-level changes of parabolic flight there are changes in torsional eye position (Cheung et al. 1994), which can be markedly asymmetric (Markham & Diamond 1993, Markham et al. 2000). This change in torsional alignment may be due to loss of compensation for otolith asymmetry in unusual g environments; on Earth, the nervous system presumably compensates for natural asymmetries (e.g., unequal otoconial mass) in otolith properties (von Baumgarten & Thumler 1979), but in other than 1 g this compensation is inappropriate and produces torsional misalignment. A similar disconjugate change has been found during space flight (Diamond & Markham 1998). Central neural compensation for such asymmetry becomes inappropriate in other than 1 g, leading to potentially disruptive changes in ocular alignment (Karmali 2007).

Sudden changes in g level can also lead to small differences in the vertical positions of the two eyes, which can result in double vision (diplopia). This is also thought to be a consequence of an asymmetry between the otolith organs on each side of the head, and has been demonstrated in our parabolic flight and laboratory studies (Karmali et al. 2006, Karmali 2007, Beaton et al. 2015).

References

KH Beaton, WC Huffman, MC Schubert (2015) Binocular misalignments elicited by altered gravity provide evidence for nonlinear central compensation. Frontiers Sys Neurosci 9.

BS Cheung, KE Money, IP Howard IP (1994) Human gaze instability during brief exposure to reduced gravity. J Vestibular Res 4:17-27.

SG Diamond, CH Markham (1998) The effect of space missions on gravity-responsive torsional eye movements. J Vestibular Res 8:217-231.

F Karmali (2007) Vertical eye misalignments during pitch rotation and vertical translation: evidence for bilateral asymmetries and plasticity in the otolith-ocular reflex. Ph.D. Thesis, Johns Hopkins University, Department of Biomedical Engineering.

F Karmali, S Ramat, M Shelhamer (2006) Vertical skew due to changes in gravitoinertial force: a possible consequence of otolith asymmetry. J Vestibular Res 16:117-125.

CH Markham, SG Diamond (1993) A predictive test for space motion sickness. J Vestibular Res 3:289-295.

CH Markham, SG Diamond, DF Stoller (2000) Parabolic flight reveals independent binocular control of otolith-induced eye torsion. Arch Ital Biol 138:73-86.

RJ von Baumgarten, R Thumler (1979) A model for vestibular function in altered gravitational states. Life Sci Space Res 17:161-170.

Progress since November 2019:

This project is in the extension of the definition phase. It is scheduled to be selected for flight (SFF), in modified form as noted below, in the fall of 2020.

On 13 December 2019, the Principal Investigator (PI) examined the crew-quarters mockup in B9 at Johnson Space Center (JSC), with Margaret Delaney and Marilyn Johnson of HRP/ROI (Research Operations & Integration element). This was done to determine the feasibility of making the sleeping compartment sufficiently dark to be able to perform the tablet version of our test.

Notes from that examination, as provided by Ms. Delaney:

• Crew quarters mock-up provides sufficient darkness for the Ocular Alignment Test.

• Some light leakage in two of the upper corners. Can be mitigated by stuffing shirts in the corners.

• Computer lights from an alternate computer in the mock-up did not interfere with the Ocular Alignment Test.

• Lower back right corner of the crew quarter mock-up provided the darkest area.

• Crew member receives a tactile vibration when submitting each trial response, to confirm response was submitted.

• Pictures of the mock-up were taken.

• Comments/Considerations

• Use of the crew sleeping bag to block light (may require Crew Office and safety approval for this).

• Evaluate the feasibility of a preflight training class for the crew. This will require approval from the Marshall Training Team.

• Lights can be turned off outside the mock-up. If deemed necessary to turn off lights in Node 2, Crew Office and safety approval will be required.

• Ask crew members (who are on the ground) that have flown how dark the crew quarters are on ISS.

• Are there other sources of ambient lights in the CQ? (ask a previously flown crew member).

• Expose the crew member to light periodically to prevent eyes adapting to the dark (i.e., modify software, flashlight, open crew door).

• Crew door did not close tightly in the mock-up. Find out if crew door on ISS seals tightly to minimize light leakage.

• Remove the trial number display on the tablet. Consider changing software for the Ocular Alignment test so the crew member knows when the torsional trials are switching to vertical trials (or vice versa) are completed, and when the whole test is completed.

After extensive testing, it was further determined that a VR (virtual reality) implementation of this assessment test (using an Oculus Rift as on ISS) will not be pursued. There are significant uncertainties about the availability of the device itself on ISS, and the software platform on which the test would have to be implemented. It is also not clear if the VR optical system can maintain proper rendering of straight lines in strict relative positions during possible misalignments of the device on the head.

Since the above efforts, we were informed that the tablet-computer version of our test will not be selected for flight in its original form. Instead, our ocular-alignment assessment will be incorporated into the Vestibular Health project. A number of discussions have been held with Scott Wood who represents that project. The combined project will use a commercial head-mounted video system to measure eye movements. Discussions are ongoing with Dr. Wood and JSC to ensure that the capabilities of the video device (resolution, stability) are sufficient to assess ocular alignment. We are also working with JSC to maintain the ability to use the original tablet-computer version of the test as a backup.

Institutional Review Board (IRB) approval in the form of a Reliance Agreement was finalized between JSC and Johns Hopkins University (JHU), for the tablet-computer version of the test. The JHU team will be added later to the Vestibular Health IRB protocol, and the JSC team will be added to the JHU protocol.

From the previous progress report, these are the issues regarding a video eye-movement device:

• Synergy with vestibular assessment project; • Less equipment overall; • Combined procedures and identical scheduling could lead to better scientific synergy; • Uncertain ability to detect small misalignments without expert operators to position the apparatus; • Sensitivity to headset misalignment and motion on head unknown; • Usable in darkness? if in darkness, does IR (infrared) lighting provide alignment cues?

This project uses a tablet computer and red/blue spectacles to assess binocular alignment and its change in International Space Station (ISS) missions of different durations. This implementation was developed with previous HRP support specifically for simplicity, ease, and minimal equipment. It is also a functional test, in that it infers misalignment through a perceptual task rather than through direct measurement of eye positions. We have been evaluating other apparatus for our experiment, which might possibly eliminate the need for complete darkness and a dedicated tablet computer. These alternatives include a head-mounted virtual-reality system similar to that already on ISS, and a head-mounted video eye-movement system under evaluation for a different ISS project. While a final decision has not yet been made, our evaluation so far heavily favors the original tablet-computer implementation. Work is underway to determine the darkness requirements for ISS implementation.