80JSC024R0002 Bedrest Standard Measures Summary for RFI.pdf

1.1 International Bedrest Standard Measures

1.1.1 Test Name: Bone Mineral Density

Measures of 2-dimensional bone mineral density (BMD) are obtained by dual-energy X-ray absorptiometry (DXA) using, e.g., a Hologic Discover Unit whole body densitometer (Hologic, Inc., Bedford, MA). Scans are obtained from the following sites: whole body, lumbar spine, and hip. The subject will remove all metal (jewelry, etc.) and clothes containing metal. Medical scrubs or other suitable clothing will be provided as necessary.

1.1.2 Test Name: Bone Marker, Hematology and Nutrition

Biological samples will be used for determination of bone mineral, nutritional and clinical status, which will include the following:

Blood Measures:

Serum Chemistry Carbon Dioxide, Blood Urea Nitrogen, Phosphorous, Magnesium, Bilirubin, Glutamyltransferase, Alkaline Phosphatase, Lactate Dehydrogenase, Creatine Kinase, Uric Acid, C Reactive Protein, Sodium, Potassium, Chloride, Creatinine, Aspartate Transaminase (AST), Alanine Transaminase (ALT), Cholesterol, Triglyceride, Glucose, Calcium

Whole Blood Analysis (CBC/differential/Platelets)

White Blood Count and differential, Red Blood Count, Hemoglobin, Mean Corpuscular Volume (MCV), Platelet Count, Reticulocyte Count Calculated values: Relative (Red Cell) Distributive Width (RDW), Hematocrit, Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration (MCHC)

Coagulation Test Fibrinogen Finger-Stick Tests (whole blood) iCa, pH, PCO2, PO2 (optional tests, if included in analysis: Na, K, glucose, hematocrit) Calculated Values: TCO2, HCO3, BE, sO2, Hgb

Hematologic and Iron Status Indicators

Transferrin Receptors, Transferrin, Ferritin, Ferritin Iron, RBC Folate, Iron, Total Iron Binding Capacity (TIBC) Calculated values: Ferritin Iron % Saturation, Transferrin Saturation

Ionized Calcium Profile Whole-blood Ionized Calcium, pH-Whole-blood

Calculated value: Ionized Calcium at pH 7.40

Hormones Thyroxine (Free T4), Thyroid Stimulating Hormone (hTSH III), Testosterone, Estradiol, Dehydroepiandrosterone Sulfate (DHEA-S), Cortisol, Cytokines: TNF alpha, IL-6

Mineral Status Zinc, Selenium, Iodine, Copper, Ceruloplasmin

Protein Status Retinol Binding Protein, Transthyretin, Total Protein, Albumin

Bone Mineral Serum/Chemistry Calcium Homeostasis

Gonadal Hormones

Endocrine Regulators

Bone Turnover Markers

(Bone Formation)

Total Calcium, Whole-blood Ionized Calcium Testosterone, Estradiol, 25-Hydroxyvitamin D, 1, 25-dihydroxyvitamin D, intact Parathyroid Hormone (PTH) Thyroxine (Free T4), Thyroid Stimulating Hormone (hTSH III), Cortisol Osteocalcin, Bone Specific Alkaline Phosphatase (BSAP), N-terminal propeptide of type 1 procollagen (P1NP)

Nutritional Assessment (if blood volume allows):

Water Soluble Vitamin Status Erythrocyte Transketolase Stimulation, Erythrocyte Glutathione Reductase Activity, Erythrocyte nicotinamide adenosine dinucleotide and nicotinamide adenosine dinucleotide phosphate (NAD/NADP), Red Cell Folate, Folate, Homocysteine, Vitamin C, Pyridoxal 5-phosphate (PLP)

Fat Soluble Vitamin Status Retinol, β-carotene, Serum Phylloquinone, α-tocopherol, Tocopherol : lipid ratio, vitamin D binding protein and plasma heme, 25-hydroxyvitamin D

Urinary Measures:

Urinalysis Specific Gravity, pH, Color, Appearance, Protein, Glucose, Bilirubin, Urobilinogen, Ketone, Nitrite, Blood, Leukocyte Esterase, Total volume, Creatinine

Minerals Calcium, Phosphorus, Magnesium, Copper, Selenium, Zinc, Iodine

Protein Status 3-methyl histidine, Nitrogen

Renal Stone Risk

Sodium, Potassium, Uric Acid, Citrate, N-telopeptide, C-telopeptide, Deoxypyridinoline

Bone Turnover Markers (Bone Resorption)

1.1.3 Test Name: Tilt Test

Subjects are instrumented pre-bed rest while supine and at -6 o for R+0 and this position is maintained while baseline data are collected for 5 minutes. The table is then tilted at a rate of approximately 7o/s to 80o placing subjects in a head-up tilt position. Subjects remain in this position for 15 minutes or until they exhibit symptoms of presyncope. Total time at 80o head-up tilt is recorded.

During the test, continuous measures are obtained for blood pressure (finger arterial and brachial artery), electrocardiography (ECG), and Doppler ultrasound of blood flow velocity in the aorta. Heart rate measures are derived from the ECG and ECG collection is synchronized with the Doppler ultrasound signals for stroke volume and cardiac output calculations. Doppler images are stored digitally for subsequent analyses.

1.1.4 Test Name: Neuromuscular Power: Vertical Jump

A ground-reaction platform is used for data collection. Data are collected with dedicated software that provides guidance to the tester and testee. The subject performs a warm-up session and is then instructed to perform two to three practice countermovement jumps at 50% of maximum effort to ensure that proper technique is understood. Once proper technique is demonstrated, the operator asks the subject to perform maximum effort jumps until three valid measurements are collected. Prior to jumping, body mass is measured during quiet stance, then the subject is instructed to jump and encouraged to elevate the head as high as possible. The subject rests 60 to 90 seconds between each jump (longer if the subject desires). Variables of peak acceleration in m/s2 (Apeak), peak velocity in m/s (Vpeak), jump height in cm (Hpeak), and peak power in kW (Ppeak) are assessed.

1.1.5 Test Name: Maximal Aerobic Capacity (VO2max)

Maximum aerobic capacity is assessed using a graded exercise protocol on an electronically-braked cycle ergometer, and a metabolic cart for gas exchange determination. Subjects wear a nose clip and breathe through a respiratory valve.

A graded exercise protocol provides an individualized approach to achieve subjects’ maximum aerobic capacity using small increments of 25W in workload increased every minute. Subjects maintain a pedaling cadence of 70 to 75 revolutions per minute (rpm). Using this protocol, maximal exercise is achieved in approximately eight to 15 mintues.

Heart rate is monitored continuously during rest (ECG monitor). Blood pressure is measured during each of the first three stages, and every two minutes during the subsequent one-minute stages, using a sphygmomanometer and stethoscope.

Measures collected (or derived) through gas exchange data include VO2, carbon dioxide elimination (VCO2), respiratory exchange rate (RER), minute ventilation (Ve), anaerobic threshold and ventilatory threshold. Workoad is also recorded.

An sdditional measure collected may include continuous finger arterial blood pressure (photoplethysmography device).

Surface EMG of seven leg muscles are also be measured during the test.

1.1.6 Test Name: Muscle Strength

Isometric and isokinetic testing provide assessments of muscle strength and endurance. Isometric maximum voluntary contractions are completed for muscles of the knee and ankle. To test isometric knee strength, the seated subject is positioned in a dynamometer and performs three sets of maximum flexion muscle contractions. For testing isometric ankle strength, the subject is placed in the supine position and three sets of maximum contractions are performed alternating between plantar flexion and dorsiflexion muscle contractions. For all isometric muscle testing, the highest value of torque (Nm) obtained is considered the subject’s maximum. Testing is continued until no further improvement is observed.

Isokinetic muscle testing assesses strength of knee, ankle and trunk musculature.

Endurance testing for muscles of the knee is also performed. Subjects complete 5 minutes of light exercise on a cycle ergometer as a warm-up. For standardization, knee and ankle testing are performed on the right lower extremity. For isokinetic testing of the knee, the subject is placed in a seated position. Knee range of motion on the dynamometer is set for 20° to 95°. The weight of the limb is assessed with the knee positioned at 30°. Isokinetic peak torque (Nm) is assessed at a speed of 60°/s. The subject performs three repetitions of continuous concentric extension and flexion motion at maximal effort.

Isokinetic testing of the ankle is done with the subject in the supine position.

Range of motion of the dynamometer is adjusted to 5° less than the subject’s maximum position of dorsiflexion and 5° less than the subject’s maximum position of plantar flexion. Weight of the limb is assessed with the ankle positioned at 15°. Isokinetic peak torque (Nm) is assessed at a speed of 30°/s.

Three repetitions of continuous concentric dorsi- and plantar flexion contractions are performed at maximal effort.

Assessment of isokinetic trunk strength is done with the subject in a seated position. Range of motion on the dynamometer is set for 0° to 90° of motion.

Weighing of the trunk is not required. Peak torque (Nm) is assessed at a speed of 60°/s. The subject performs three repetitions of continuous concentric flexion and extension motion at maximal effort.

1.1.7 Test Name: Immunology

Immunology testing collects the following:

• Basic leukocyte subsets o T-cells (CD3 positive) o B-cells (CD19 positive) o NK cells (CD3 negative, CD16 and CD56 positive)

• Stress hormone levels o Salivary cortisol o Plasma cortisol

• Plasma immunoglobulin G (IgG) levels

• Viral antibody levels o Varicella zoster virus (VZV) o Cytomegalovirus infection (CMV)

• Alpha 1 globulin, alpha 2 globulin, beta globulin, gamma globulin

1.1.8 Test Name: Postural Equilibrium Control

This test will characterize changes in postural control following bed rest. This test utilizes computerized dynamic posturography (CDP) to quantitatively assess both sensory and motor components of postural control. The Sensory Organization Tests (SOTs) objectively evaluate one’s ability to make effective use of (or suppress inappropriate) visual, vestibular, and proprioceptive information for balance control. The Motor Control Tests (MCTs) evaluate one's ability to automatically recover from unexpected support surface perturbations.

The standard SOT protocol with head erect is comprised of six conditions involving two support surface conditions (fixed and sway- referenced) and three visual conditions (eyes open, eyes closed and sway-referenced surround). Two additional modified SOT conditions are used to increase sensitivity and specificity by including dynamic head tilts with eyes closed on either fixed or sway-referenced support surface. The dynamic tilts involve pitching the head at 0.33 Hz (± 20°) paced by an audible tone. For each SOT trial, data are recorded for 20 seconds or until there is a fall. Table 3 describes the SOT tests.

The MCTs assess the patient's ability to quickly and automatically recover from unexpected support surface perturbations. Large forward and backward platform translations (400 ms, amplitude scaled to the subject height, approximately 2.3 inches for a 6- foot-tall subject) are performed to elicit automatic postural responses. Throughout each SOT and MCT trial, subjects are instructed to maintain stable upright posture with arms folded across the chest. External auditory orientation cues are masked by white noise supplied through headphones. Center-of-mass sway angles are estimated from instantaneous anterior-posterior (AP) and medial-lateral (ML) center-of-force positions computed from force transducers mounted within the test platform force plates.

The AP peak-to-peak sway angle (p-p sway) is used to compute the equilibrium score, where 12.5 is the maximum theoretical p-p sway.

1.1.9 Test Name: Functional Mobility Test

Sit-to-Stand with Walk & Turn – Participants will be requested to rise from a seated position as quickly as possible without using their hands and stand for 10 seconds. Following 10 s, subjects will be commanded to walk as quickly and safely as possible straight ahead towards a cone (4m distance), walk around the cone, return back to the chair stepping over an obstacle on the way back and sit back down in the chair. This will be repeated 3 times, with the obstacle height increasing from 5 to 10 to 15 cm. Video of each trial will be recorded and body motion (head and torso) will be recorded from triaxial inertial measurement units.

Performance during the sit-to-stand will include settling time after standing and postural sway. Performance during the walk-and-turn will include time to complete each trial, turn rate during the turn, obstacle contact, and head-torso coordination.

Tandem Walk – Participants will walk 10 heel-to-toe steps with their arms folded across their chests and their eyes closed (3 trials) followed by one trial with their eyes open. Video of each trial will be recorded and body motion (head and torso) will be recorded from triaxial inertial measurement units. The percent correct steps (a greater value of the percent correct steps directly relates to better performance) will be calculated from the video recordings, and head-torso coordination and postural sway will be calculated from the inertial measurement units.

1.1.10 Test Name: Treadmill Locomotion Test

The treadmill test uses gradually increasing locomotor loads on the treadmill. A distinctive feature of the test is the standardization of the sequence and length of each of the five load levels with voluntary selection of work intensity within each level. The speed limits of slow, moderate, and fast running are self-selected by the subject. Parameters collected during each of the five load levels are running speed (m/s) and heart rate (bpm). The intensity of work performed is then expressed as the ratio of peak heart rate to peak running velocity (beats/60 m).

The treadmill test consists of several steps: warm-up walking for 3 minutes, slow running for 2 minutes, moderate running for 2 minutes, fast running for 1 minute, and walking for 3 minutes as the final step. The test is performed in idling regimen (passive mode) of treadmill. In this mode, the treadmill belt is driven by the force of the running subject. The length of the test is 11 minutes, and the energy expended during the experiment is approximately 100 kcal.

1.1.11 Test Name: Ocular Tests

Intraocular Pressure – Intraocular pressure (IOP) is the fluid pressure of the aqueous humor inside the anterior chamber of the eye. Tonometry will be performed on the right and left eye in seated subjects using a commercial tonometer. The operator will stabilize the subject’s head and gently tap the tonometer tip to the clear surface of the open eye directly over the pupil to obtain the measurement. Each measurement consists of six successive taps and the tonometer automatically drops the highest and lowest values, and reports the mean of the remaining four values; this constitutes one measurement. If the variability between four taps is too high, the device reports “deviation error”. This measurement should not be reported. Three good measurements are required and should fall within a range of 1.5 mmHg. Continue taking measurements until three measurements fall within 1.5 mmHg of each other.

Ocular Ultrasound – The diameter of the optic nerve and nerve sheath will be measured in both eyes of supine subjects. Other parameters that will be derived from the ocular ultrasound scan include assessment of optic nerve tortuosity, and the ratio of optic sheath-to-optic nerve diameter. The ultrasound scan will also be used to measure anterior-posterior globe diameter and identify changes in globe morphology, including flattening of the posterior globe.

Optical Coherence Tomography– Optical coherence tomography (OCT) is a diagnostic imaging technique that involves measurements of retinal thickness, volume, and retinal nerve fiber layer (RNFL) thickness using a method of quantitative cross-sectional analysis. The OCT software is able to identify and "trace" key layers of the retina, the internal limiting membrane, the nerve fiber layer, and the retinal pigment epithelium. Axial samples of A-scans are obtained in each "scan pass“. When all of the A-scans are combined into one image, the image has a resolving power of about 10 microns vertically and 20 microns horizontally. Consequently, OCT has a high sensitivity for detecting subtle changes to the RNFL of the optic nerve head. An anterior segment module allows measurement of corneal thickness, anterior scleral thickness, and anterior chamber angles. Subjects are seated and place their chin on a chin rest while focusing their eyes into a machine. The machine performs a scan and the image and device generated report are viewed by the ophthalmologist or optometrist.

1.1.12 Test Name: Psychological Testing

Positive and Negative Affect Scale (PANAS) – The PANAS is a 20-item self-evaluation questionnaire that measures affect, or indicators of emotional states or mood.

General Health Questionnaire (GHQ) – GHQ is a 28-item self-evaluation questionnaire measuring the current mental state of the individual, and is more clinically oriented mental health assessment targeting symptoms of anxiety and depression.

1.1.13 Test Name: Physiotherapy

Sixty(60) minutes of physiotherapy is provided for bed rest subjects during the in-phase and post-bed rest phase as outlined below:

Physiotherapy Phase 1 (HDT1-HDT10) The first phase occurs when the subjects are first confined to bed rest. It is anticipated that the subjects will be experiencing lower back discomfort and as a result, the objective of this phase will be to aid in the overall comfort of the subject. These sessions will be performed every other day focusing primarily on upper and lower back, neck, and shoulders.

Physiotherapy Phase 2 (HDT11-HDT20) The second phase occurs when the subjects have acclimated to bed rest. The focus of this phase will shift to the lower back, legs and feet with the objective being to aid in circulation of the lower extremities. These sessions will be performed every other day.

Physiotherapy Phase 3 (HDT21-HDT30) The third phase occurs when the subject is preparing to stand after bed rest. Foot discomfort due to disuse has been reported during post-bed rest testing. The overall objective of this phase is to help aid the subject’s body toward a quick recovery by increasing circulation of the lower extremities; however, the feet will be a focal point to help alleviate the reported discomfort. These sessions will be performed every other day.

Physiotherapy Phase 4 (R+0-R+6) The fourth and final phase occurs when the subject has completed bed rest and returned to the ambulatory phase. The body will be significantly deconditioned.

This physiotherapy will help rehabilitate and prepare the subject for departure from the unit. The objective of this phase will be to aid in the overall comfort of the subject keeping in mind muscle aches and discomfort are expected due to the return to physical activity. These sessions will be performed daily with a primary focus on upper and lower back, neck, and shoulders.

1.1.14 Test Name: Reconditioning

Facility designated personnel will evaluate subjects at the beginning of the pre-bed rest phase and upon re-ambulation. Using this evaluation, a unique protocol for reconditioning is developed. Standard reconditioning exercises include aerobic conditioning, plyometrics, balance, cone walks, strength, abdominals, and stretching. Seven days of reconditioning is a guideline; facility designated personnel will modify the length and exact schedule of the protocol as needed for the progression of each subject. Reconditioning exercises are introduced in a baseline familiarization session and then occur daily R+4 through R+11.

1.1.15 Test Name: Stretching

Stretching exercises will be performed daily in the morning and every other afternoon supervised by a Physiotherapist for 15 to 30 minutes per session during the pre- and in-bed rest phases. All stretching exercises during pre- and post-bed rest will be performed in the horizontal position.

In-bed rest stretching exercises will stretch muscles surrounding the hip, knee, ankle, shoulder, wrist, and cervical lumbar spine, and the isometric exercises will include contractions of muscle groups including hip flexors and extensors, knee extensors, and abdominal muscles. Subjects will be trained by staff on the specific stretches to be performed. All stretching exercises during bed rest will be performed in the head-down position.