NOTE: Extended to 3/31/2021 per D. Risin/JSC and NSSC information (Ed., 8/26/20)

NOTE: Extended to 9/30/2020 per NSSC information (Ed., 10/18/19)

The specific aims include: 1. Integrative evaluation of the cerebral physiological effects of AG during the 60 day bed rest period using between group and within group comparisons, and 2. Assessment of the acute dynamic changes in the human body systems related to the centrifugation regimen.

The methods and techniques used to achieve these objectives include: non-invasive assessment of ICP (intracranial pressure), cerebral blood flow, cerebral blood volume, CSF (cerebrospinal fluid) flow and volumes, ocular anatomy and physiology, and neurovestibular function.

This proposal will deliver an integrated view of the physiological, anatomical, and functional effects of intermittent centrifugation (artificial gravity) on the cerebrovascular, ocularm, and vestibular systems. This will provide important insights into the effectiveness of this form of artificial gravity to counteract the headward fluid shifting of head down tilt, which may yield important knowledge about the future utility of this method as a countermeasure for the spaceflight-induced headward fluid shifts and the Spaceflight Associated Neuro-ocular Syndrome (SANS).

1) Completion of subject enrollment and procedures. 24 of 24 total subjects were enrolled with successful completion of all study procedures

2) Data analysis completed for the eye measures including:

- Optical coherence tomography based total retinal nerve fiber layer thickness; - Optical biometry; - Intraocular pressure; - Chorioretinal folds and thickness; - Refractive error; - Automated perimetry derived axial length; - Posterior globe flattening; - Eye movement measurements

3. Data analysis completed for the following brain measures:

- Near infrared spectroscopy derived cerebral blood volumes, arterial blood pulsatility

- MRI structural measures including lateral ventricular volumes, total brain volume

- MRI flow measures included CSF flow, cerebral arterial flow

- Transcranial doppler derived cerebral blood flow velocities and cerebral autoregulation

- cFLOW cerebral blood flow index

- Internal jugular vein cross sectional areas.

Several manuscripts are under preparation for posterior globe deformation, near infrared spectroscopy, internal jugular vein area, transcranial Doppler blood flow, and MRI brain.

NOTE: Extended to 9/30/2020 per NSSC information (Ed., 10/18/19)

The specific aims include: 1. Integrative evaluation of the cerebral physiological effects of AG during the 60 day bed rest period using between group and within group comparisons, and 2. Assessment of the acute dynamic changes in the human body systems related to the centrifugation regimen.

The methods and techniques used to achieve these objectives include: non-invasive assessment of ICP (intracranial pressure), cerebral blood flow, cerebral blood volume, CSF (cerebrospinal fluid) flow and volumes, ocular anatomy and physiology, and neurovestibular function.

This proposal will deliver an integrated view of the physiological, anatomical, and functional effects of intermittent centrifugation (artificial gravity) on the cerebrovascular, ocularm, and vestibular systems. This will provide important insights into the effectiveness of this form of artificial gravity to counteract the headward fluid shifting of head down tilt, which may yield important knowledge about the future utility of this method as a countermeasure for the spaceflight-induced headward fluid shifts and the Spaceflight Associated Neuro-ocular Syndrome (SANS).

The following procedures were successfully conducted in all participants with no major technical issues: Transcranial doppler, cerebral perfusion monitoring (cFLOW), near infrared spectroscopy, internal jugular vein ultrasound, optical coherence tomography, intraocular pressure, optical biometry, visual acuity, visual field testing, cycloplegic refraction, field testing (sit-to-stand, recovery from fall, jump down test, standing on foam, tandem walk), iPAS (eye movements), MRI: brain and eye structure, CSF flow, cerebral blood flow, globe imaging, and transcutaneous CO2 measurement during sleep.

Data analysis will be ongoing until study completion September 2020.

The specific aims include: 1. Integrative evaluation of the cerebral physiological effects of AG during the 60 day bed rest period using between group and within group comparisons, and 2. Assessment of the acute dynamic changes in the human body systems related to the centrifugation regimen.

The methods and techniques used to achieve these objectives include: non-invasive assessment of ICP (intracranial pressure), cerebral blood flow, cerebral blood volume, CSF (cerebrospinal fluid) flow and volumes, ocular anatomy and physiology, and neurovestibular function.

This proposal will deliver an integrated view of the physiological, anatomical, and functional effects of intermittent centrifugation (artificial gravity) on the cerebrovascular, ocularm, and vestibular systems. This will provide important insights into the effectiveness of this form of artificial gravity to counteract the headward fluid shifting of head down tilt, which may yield important knowledge about the future utility of this method as a countermeasure for the space-flight induced headward fluid shifts and the Spaceflight Associated Neuro-ocular Syndrome (SANS).

Development of a ground based analog is essential to understanding the anatomical and physiological processes that may be occurring in the spaceflight environment, and will also allow for the development of countermeasures to reduce the adverse effects of microgravity. Our project is designed to monitor the brain and eye changes occurring in a bed rest analog that combines 6 degree head down tilt with an artificial gravity countermeasure using short-arm centrifugation.

In the current phase, the devices and methods for testing have been determined. The devices were selected both for ease of use, non-invasive and safe, and monitoring important physiological parameters of the brain and/or eye.

A dry run was successfully completed in Cologne, Germany at the German Aerospace Center in September 2018. The devices were tested on a test subject on the centrifuge and the measurements confirmed fluid redistribution from the head to the legs when the artificial gravity was active. Good quality physiological signals were obtainable, and efficiencies for combining several devices simultaneously were found. This will allow for more efficient testing of the healthy subjects during the study phase, and also allow for better understanding of the physiological changes as assessed by multiple modalities in real time.

The tentative start of the 60 day bedrest study is March 2019.

The specific aims include: 1. Integrative evaluation of the cerebral physiological effects of AG during the 60 day bed rest period using between group and within group comparisons, and 2. Assessment of the acute dynamic changes in the human body systems related to the centrifugation regimen.

The methods and techniques used to achieve these objectives include: non-invasive assessment of ICP (intracranial pressure), cerebral blood flow, cerebral blood volume, CSF (cerebrospinal fluid) flow and volumes, ocular anatomy and physiology, and neurovestibular function.

This proposal will deliver an integrated view of the physiological, anatomical, and functional effects of intermittent centrifugation (artificial gravity) on the cerebrovascular, ocularm, and vestibular systems. This will provide important insights into the effectiveness of this form of artificial gravity to counteract the headward fluid shifting of head down tilt, which may yield important knowledge about the future utility of this method as a countermeasure for the space-flight induced headward fluid shifts and the Spaceflight Associated Neuro-ocular Syndrome (SANS).

Integration of this study with other US and European teams is proceeding well, and efficiencies between studies integrated into the uniform platform at enhivab (German Aerospace Center) are being identified.

The study methodology will be presented at NASA Human Research Program Investigators' workshop in Jan 2018.

Dry run is tentatively scheduled for late spring/early summer 2018 in Cologne, Germany.

The specific aims will include: 1. Integrative evaluation of the cerebral physiological effects of AG during the 60 day bed rest period using between group and within group comparisons, and 2. Assessment of the acute dynamic changes in the human body systems related to the centrifugation regimen.

The methods and techniques used to achieve these objectives include: non-invasive assessment of ICP (intracranial pressure), cerebral blood flow, cerebral blood volume, CSF (cerebral spinal fluid) flow and volumes, ocular anatomy and physiology, and neurovestibular function.

This proposal will deliver an integrated view of the physiological, anatomical and functional effects of intermittent centrifugation (artificial gravity) on the cerebrovascular, ocularm and vestibular systems. This will provide important insights into the effectiveness of this form of artificial gravity to counteract the headward fluid shifting of head down tilt, which may yield important knowledge about the future utility of this method as a countermeasure for the space-flight induced headward fluid shifts and the visual impairment/intracranial pressure (VIIP) syndrome.