Adv Physiol Educ. Mar;37(1) doi: /advan Cold stress and the cold pressor test. Silverthorn DU(1), Michael J. Author information. Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test. The cold pressor test is a cardiovascular test performed by immersing the hand into an ice water container, usually for one minute, and measuring changes in.
test. Cold stress
Further work is warranted to confirm these findings. Detection of diminished response to cold pressor test in smokers: After obtaining informed consent, ten healthy male non-smokers mean age: MBF was calculated as coronary sinus flow divided by the left ventricular LV mass which was given as a total LV myocardial volume measured on cine MRI multiplied by the specific gravity 1.
Pain threshold elapsed time until the child reported pain and pain tolerance total time the child kept the hand submerged in the cold water were measured for each cold pressor trial. Older children appeared to experience additional benefits from using the helmet, whereas younger children benefited equally from both conditions.
The findings suggest that virtual reality technology can enhance the effects of distraction for some children. Research is needed to identify the characteristics of children for whom this technology is best suited. Effects of videogame distraction using a virtual reality type head-mounted display helmet on cold pressor pain in children.
To test whether a head-mounted display helmet enhances the effectiveness of videogame distraction for children experiencing cold pressor pain. Forty-one children, aged years, underwent one or two baseline cold pressor trials followed by two distraction trials in which they played the same videogame with and without the helmet in counterbalanced order.
Both distraction conditions resulted in improved pain tolerance relative to baseline. Cold pressor stimulus temperature and resting masseter muscle haemodynamics in normal humans. Cold pressor stimulation reportedly increases sympathetic nerve activity in human skeletal muscles.
This study examined the effect of cold pressor stimulation on the resting haemodynamics of the right masseter muscle in normal individuals, using near-infrared spectroscopy.
Nine healthy non-smoking males with no history of chronic muscle pain or vascular headaches participated. Their right hand was immersed in a water bath 4, 10, 15 degrees C for exactly 1 min.
Each trial lasted 7 min 1 min before, 1 min during, 5 min after stimulation and a strictly random order was utilized for the three test temperatures and the mock trial. Masseter muscle haemoglobin concentration and oxygen saturation, as well as heart rate and blood pressure, were continuously recorded in each trial. After completing the four trials, each participant produced and sustained a s maximum voluntary clench in the intercuspal position.
Data across the four trials were baseline-corrected and then magnitude-normalized to the individual's highest absolute haemoglobin and oxygen signal during the s maximal clenching effort. Haemoglobin and oxygen saturation increased progressively during cold pressor stimulation as the water temperature decreased Hb, p cold pressor , stimulation induces a strong increase in intramuscular blood volume which appears to be due to both a local vasodilative response and increased cardiac output.
Active and passive distraction using a head-mounted display helmet: The current study tested the effectiveness of interactive versus passive distraction that was delivered via a virtual reality type head-mounted display helmet for children experiencing cold pressor pain. Forty children, aged 5 to 13 years, underwent 1 or 2 baseline cold pressor trials followed by interactive distraction and passive distraction trials in counterbalanced order.
Pain threshold and pain tolerance. Children who experienced either passive or interactive distraction demonstrated significant improvements in both pain tolerance and pain threshold relative to their baseline scores.
In contrast, children who underwent a second cold pressor trial without distraction showed no significant improvements in pain tolerance or threshold. Although both distraction conditions were effective, the interactive distraction condition was significantly more effective. Implications for the treatment of children's distress during painful medical procedures are discussed.
The illusion of presence influences VR distraction: This study investigated whether VR presence influences how effectively VR distraction reduces pain intensity during a cold-pressor experience. Thirty-seven healthy students underwent a cold pressor task while interacting with a VR distraction world.
After the VR cold-pressor experience, each subject provided VAS ratings of the most intense pain experienced during the hand immersion and rated their illusion of having been inside the virtual world.
Results showed that the amount of VR presence reported correlated significantly and negatively with ratings of pain intensity. The importance of using an appropriately designed VR to achieve effective VR analgesia is highlighted.
Haemodynamic responses in chronically painful, human trapezius muscle to cold pressor stimulation. The aim was to compare haemodynamic responses in trapezius muscles to cold pressor stimulation in individuals with localized trapezius myalgia and asymptomatic controls. Nine males with chronic localized pain in the trapezius mean age, Two experimental cold pressor and mock trials were performed in a randomly assigned sequence.
In the cold pressor trial the participant's left foot and ankle were immersed in 4 degrees C cold water for 2 min; the mock trial was done without that stimulus. Blood volume was continuously recorded 1 min before, 2 min during, and 5 min after cold pressor stimulation using near-infrared spectroscopy. Each participant's blood-volume data were baseline-corrected and submitted to statistical analysis.
Upon withdrawal of that stimulation, the mean blood volume in both groups fell below the baseline. These results suggest that individuals with chronic regional trapezius myalgia have less capacity to vasodilate this muscle during cold pressor stimulation than those without such myalgia. It is not yet known if this difference in the haemodynamic response is a cause or an effect of the myalgia.
C-reactive protein and cold-pressor tolerance in the general population: The aim of this study was to examine whether increases in severity of subclinical inflammation, measured by high-sensitivity C-reactive protein hs-CRP , increased experimental pain sensitivity, measured by cold-pressor tolerance, and to test whether this relationship is independent of chronic pain. For the present analysis, complete data for 10, participants age: The fully adjusted model was controlled for age, sex, education, body mass index, smoking status, alcohol consumption, emotional distress, statin usage, and self-reported presence of chronic pain.
Additional analysis was performed in participants without chronic pain. A year-old male presented with chest discomfort while sleeping. The patient was suspected of having vasospastic angina VSA and underwent hyperventilation and cold-pressor stress echocardiography. No chest pain, ECG changes or decreased wall motion was found. However, automated function imaging AFI showed decreased peak systolic strain at the apex and postsystolic shortening at both the apex and inferior wall, which was not found before the test.
The patient was thus diagnosed as having VSA. The present case demonstrates the usefulness of AFI combined with hyperventilation and cold-pressor stress echocardiography as a screening examination for VSA. Validation of normalized pulse volume in the outer ear as a simple measure of sympathetic activity using warm and cold pressor tests: Normalized pulse volume NPV derived from the ear has the potential to be a practical index for monitoring daily life stress.
However, ear NPV has not yet been validated. Therefore, we compared NPV derived from an index finger using transmission photoplethysmography as a reference, with NPV derived from a middle finger and four sites of the ear using reflection photoplethysmography during baseline and while performing cold and warm water immersion in ten young and six middle-aged subjects.
The results showed that logarithmically-transformed NPV lnNPV during cold water immersion as compared with baseline values was significantly lower, only at the index finger, the middle finger and the bottom of the ear-canal. In conclusion, these findings show that reflection and transmission photoplethysmography are comparable methods to derive NPV in accordance with our theoretical prediction.
NPV derived from the bottom of the ear-canal is a valid approach, which could be useful for evaluating daily life stress. Hostility and Facial Affect Recognition: The effects of hostility and a cold pressor stressor on the accuracy of facial affect perception were examined in the present experiment.
A mechanism whereby physiological arousal level is mediated by systems which also mediate accuracy of an individual's interpretation of affective cues is described. Right-handed participants were classified as…. Does Avatar Point of View Matter? Abstract This study tested the effects of distraction using virtual-reality VR technology on acute pain tolerance in young adults.
The length of time participants tolerated the cold -water exposure pain tolerance under each distraction condition was compared to a baseline no distraction trial. Results demonstrated that participants had significantly higher pain tolerance during both VR-distraction conditions relative to baseline no distraction trials.
Although participants reported a greater sense of presence during the first-person condition than the third-person condition, pain-tolerance scores associated with the two distraction conditions did not differ. The types of VR applications in which presence may be more or less important are discussed. Virtual-reality distraction and cold-pressor pain tolerance: This study tested the effects of distraction using virtual-reality VR technology on acute pain tolerance in young adults.
Two different game views were tested that were hypothesized to affect the degree to which participants felt "present" in the virtual environment: Subjects also rated the degree to which they felt "present" in the virtual environment after each distraction trial.
Genetic factors influence blood pressure BP response to the cold pressor test CPT , which is a phenotype related to hypertension risk.
Both single-marker and haplotype association analyses were conducted using linear mixed models. This study examined whether increasing the demand for central cognitive processing involved in a distraction task, by involving the child in ongoing, effortful interaction with the distraction stimulus, would increase children's tolerance for cold pressor pain. Seventy-nine children ages years underwent a baseline cold pressor trial followed by two cold pressor trials in which they received interactive distraction i.
Both distraction conditions were presented via a virtual reality-type helmet. As expected, children demonstrated significant improvement in pain tolerance during distraction relative to baseline. Children showed the greatest improvement during the interactive distraction task. The effects of distraction on children's cold pressor pain tolerance are significantly enhanced when the distraction task also includes greater demands for central cognitive processing.
Research has demonstrated that values and acceptance interventions can increase distress tolerance, but the individual contribution of each remains unclear.
The current study examined the isolated effect of a values intervention on immersion time in a cold pressor. Immersion time increased Increases in self-reported pain and distress predicted decreases in immersion time for Control, but not Values, participants.
Results suggest that a brief isolated values exercise can be used to improve distress tolerance despite increased perceptions of pain and distress, such that values alone may be sufficient to facilitate openness to difficult experiences. Effect of acute transdermal estrogen administration on basal, mental stress and cold pressor -induced sympathetic responses in postmenopausal women.
Administration of estrogen has vascular effects through poorly defined mechanisms that may include sympathetic withdrawal. A p-value, adjusted for multiple comparisons, of test , and during a cold pressor test.
Estrogen did not attenuate basal or stimulated hemodynamic responses significantly. The increase in mean arterial pressure after the Stroop test 5. Basal, mental stress and cold pressor -stimulated norepinephrine spillover were not significantly affected by short-term estrogen administration. Norepinephrine spillover tended to be higher after estrogen Acute transdermal estrogen administration did not attenuate norepinephrine spillover or sympathetically mediated hemodynamic responses.
Incongruence of pain severity ratings among people experiencing pain and their observers has been linked to psychological distress. Previous studies have measured pain rating congruence through static self-report, involving a single rating of pain; however, this method does not capture changes in ratings over time. The present study examined the extent to which partners were congruent on multiple ratings of a participants' pain severity during the cold pressor task.
Furthermore, 2 components of pain anxiety-pain catastrophizing and perceived threat-were examined as predictors of pain congruence. Both partners completed measures of pain catastrophizing and perceived threat before randomization to their cold pressor participant or observer roles. Participants and observers rated the participant's pain in writing several times over the course of the task.
On average, observers rated participants' pain as less severe than participants' rated their own pain. In addition, congruence between partners increased over time because of observers' ratings becoming more similar to participant's ratings.
Finally, pain catastrophizing and perceived threat independently and jointly influenced the degree to which partners similarly rated the participant's pain.
This article presents a novel application of the cold pressor task to show that pain rating congruence among romantic partners changes over time. These findings indicate that pain congruence is not static and is subject to pain anxiety in both partners. Published by Elsevier Inc. Effects of playing video games on pain response during a cold pressor task.
Two studies assessed whether playing video games would significantly distract participants from painful stimulation via a cold pressor test. No differences were found on scores of aggressiveness, competitiveness, or prior video game experience, suggesting that these factors play little role.
Video game play produced an increase in pulse, which was greatest during the action, fighting, sports, and boxing games. Pain tolerance was greatest during the sports and fighting games. Thus, certain games produce greater distraction, which may have implications for the medical field as an adjunct to pain management. The effects of coping style on virtual reality enhanced videogame distraction in children undergoing cold pressor pain.
This study sought to evaluate the effectiveness of virtual reality VR enhanced interactive videogame distraction for children undergoing experimentally induced cold pressor pain and examined the role of avoidant and approach coping style as a moderator of VR distraction effectiveness.
As predicted, children demonstrated significant improvement in pain tolerance during both interactive videogame distraction conditions. However, a differential response to videogame distraction with or without the enhancement of VR technology was not found. Children's coping style did not moderate their response to distraction.
Rather, interactive videogame distraction with and without VR technology was equally effective for children who utilized avoidant or approach coping styles. Participants underwent a baseline cold pressor trial followed by interactive distraction trial, passive distraction trial, or second baseline trial. One or two additional trials followed.
Children originally assigned to distraction received the alternate distraction intervention. Controls participated in both interactive and passive distraction trials in counterbalanced order. The two distraction conditions did not differ. Future studies should examine whether more extensive training would enhance effects of interactive video game distraction.
Cardiovascular and sympathetic neural responses to handgrip and cold pressor stimuli in humans before, during and after spaceflight. Fu, Qi; Levine, Benjamin D. Astronauts returning to Earth have reduced orthostatic tolerance and exercise capacity. Alterations in autonomic nervous system and neuromuscular function after spaceflight might contribute to this problem.
In this study, we tested the hypothesis that exposure to microgravity impairs autonomic neural control of sympathetic outflow in response to peripheral afferent stimulation produced by handgrip and a cold pressor test in humans. We studied five astronauts approximately 72 and 23 days before, and on landing day after the 16 day Neurolab STS space shuttle mission, and four of the astronauts during flight day 12 or The cold pressor test was applied only before five astronauts and during flight day 12 or 13, four astronauts.
At the same relative fatiguing force, the peak systolic pressure and mean arterial pressure during static handgrip were not different before, during and after spaceflight. Contraction-induced rises in heart rate were similar pre-, in- and post-flight. Similarly, responses of MSNA and blood pressure. The Role of Cognitive Processing. Predictors of trait dissociation and peritraumatic dissociation induced via cold pressor. Understanding which factors predict individual dissociative response during stressful situations is important to clarify the nature of dissociation and the mechanisms associated to its use as a coping strategy.
The present study examined 1 whether experiential avoidance EA , anxiety sensitivity AS , depressive symptoms, and state anxiety concurrently predicted trait dissociation TD -absorption, amnesia, depersonalization, and total TD scores-and laboratory induced dissociation LID ; and 2 whether TD and catastrophizing predicted LID.
We also examined whether catastrophizing mediated the relationships between both AS and depressive symptoms and LID. A total of female undergraduate students participated in a cold pressor task, which significantly induced dissociation.
Results of hierarchical regression analyses showed that AS at Time 1 9 months before the experimental session , as well as depressive symptoms and catastrophizing at the time of the experiment Time 2 , predicted LID at Time 2. Depressive symptoms at Time 2 predicted total TD, absorption, and amnesia scores.
AS at Time 1 and depressive symptoms at Time 2 predicted depersonalization. AS, depressive symptoms, and catastrophizing seem to facilitate the use of dissociative strategies by healthy individuals, even in response to non-traumatic but discomforting stress. Relationship between cold pressor pain-sensitivity and sleep quality in opioid-dependent males on methadone treatment.
Poor sleep quality due to pain has been reported among opioid-dependent male patients on methadone maintenance therapy MMT but objective pain data are lacking. This study aimed to investigate the rate of pain-sensitivity using cold pressor test CPT and the relationship between pain-sensitivity and sleep quality in this population.
A total of male participants were included into the study. Objective pain-tolerance was evaluated at 0 h and at 24 h after the first CPT. The mean age of study participants was Mean daily methadone dose was The averaged pain-tolerance time ranged from 7 to s with a mean time of With analysis of covariance, pain-sensitive group was found to have higher global PSQI scores adjusted mean 5. Majority of opioid-dependent male patients on methadone treatment are pain-sensitive with CPT.
Poor sleep quality is associated with cold pressor pain-sensitivity. Pain and sleep complaints in this male population should not be overlooked. Effects of videogame distraction and a virtual reality type head-mounted display helmet on cold pressor pain in young elementary school-aged children. This study examined the effects of videogame distraction and a virtual reality VR type head-mounted display helmet for children undergoing cold pressor pain. Fifty children between the ages of 6 and 10 years underwent a baseline cold pressor trial followed by two cold pressor trials in which interactive videogame distraction was delivered via a VR helmet or without a VR helmet in counterbalanced order.
As expected, children demonstrated significant improvements in pain threshold and pain tolerance during both distraction conditions. However, the two distraction conditions did not differ in effectiveness. Using the VR helmet did not result in improved pain tolerance over and above the effects of interactive videogame distraction without VR technology. Clinical implications and possible developmental differences in elementary school-aged children's ability to use VR technology are discussed.
Comparisons of catastrophizing, pain attitudes, and cold-pressor pain experience between Chinese and European Canadian young adults. Experimental pain research indicates ethnic differences in pain experience. Most of the cross-cultural pain research studied African Americans and Hispanics with little data available for Asian groups. This study examined differences in pain catastrophizing, pain attitudes, and pain responses between Chinese and European Canadian young adults.
Prior to completing a cold-pressor CP task, 80 Chinese and 80 European Canadian undergraduate students were administered measures of pain catastrophizing and pain attitudes, including stoicism and cautiousness. Pain threshold, pain tolerance, and pain intensity were measured during the CP task. The Short Form-McGill Pain Questionnaire was administered immediately postimmersion to measure sensory and affective pain. While there was no group difference in pain threshold and pain intensity, Chinese participants displayed lower pain tolerance and reported higher SF-MPQ-Affective than European Canadians.
Regarding psychological variables, there was no difference in stoicism and cautiousness between groups, but Chinese participants reported greater pain catastrophizing.
The implications of the findings and future research were discussed. The study found ethnic differences in cold-pressor responses, in which Chinese undergraduates reported higher levels of pain compared to their Euro-Canadian counterparts.
The finding that pain catastrophizing mediated the ethnic difference in SF-MPQ-Affective scores indicated the importance of examining the role of catastrophizing in pain reports from Chinese and Euro-Canadian patients. Chronic pain frequently involves cognitive complaints such as concentration and memory deficits, but studies of the effects of pain on cognition have not consistently demonstrated deficits and have not typically utilized standard neuropsychological instruments.
Scaled scores for normal administration versus pain or painless water immersion did not differ and there was no interaction between group control vs. Results indicate that induced pain in nonclinical volunteers does not impair PSI or WMI performance, and they suggest that chronic pain per se should not be expected to substantially affect these cognitive functions. However, patients with chronic pain may differ from nonclinical volunteers in their experience of pain, potentially limiting generalizability.
Effect of intravenous infusion of a beta-adrenergic blocking agent on the haemodynamic changes in human masseter muscle induced by cold-pressor stimulation.
Eight healthy non-smoking males mean age: Haemoglobin Hb and oxygen O2 saturation in the right masseter muscle were continuously recorded with a non-invasive near-infrared spectroscopic device.
Heart rate and blood pressure were also recorded. The experiment had three phases: The saline and drug trials each involved continuous recording for 1 min before, 2 min during and 5 min after the cold-pressor stimulation 4 degrees C.
This infusion was begun 20 min before the baseline recording and participants did not know which solution saline or propranolol was being infused. For the MVC trial, each participant was asked to perform a sec clench of their jaw-closing muscles. There was a rest period of 15 min between each trial. The individual Hb and O2 data were normalized so that the baseline at the beginning of the experiment was equal to zero, and the Hb and O2 data were normalized as a percentage of the individual's own highest absolute Hb and O2 after and during the MVC, respectively.
The mean Hb rebound change after the cold-pressor stimulation in the beta-blocker trial was significantly higher than in the placebo trial, and no significant heart-rate differences were observed in the period after cold-pressor stimulation. Overall, the mean heart rate before and during that. Response inhibition predicts painful task duration and performance in healthy individuals performing a cold pressor task in a motivational context.
Long-term avoidance of painful activities has shown to be dysfunctional in chronic pain. Pain may elicit escape or avoidance responses automatically, particularly when pain-related fear is high. An inhibitory control system may resolve this conflict. Response inhibition was measured with the stop-signal task, and pain-related fear with the Fear of Pain Questionnaire.
Participants completed a tone-detection task TDT in which they could earn money while being exposed to cold pressor pain. Pain after the CPT was associated with pain-related fear, but not with response inhibition. In contrast, the relation between response inhibition and number of hits on the TDT was most pronounced for those with lower pain-related fear. The cold pressor task CPT is increasingly used to induce experimental pain in children, but the specific methodology of the CPT is quite variable across pediatric studies.
This study examined how subtle variations in CPT methodology eg. Parents and children in the high-threat condition expected greater child pain, and these children reported higher perceived threat of pain and state pain catastrophizing. For children in the low-threat condition, an informed ceiling was associated with less state pain catastrophizing during the CPT. Pain intensity, tolerance, and fear during the CPT did not differ by experimental group, but were predicted by child characteristics.
Findings suggest that provision of threatening information may impact anticipatory outcomes, but experienced pain was better explained by individual child variables. Effect of cold pressor stimulation 4 degrees C on human masseter muscle haemodynamics during and after sustained isometric contraction.
Total haemoglobin was measured in the masseter before, during and after the contraction task using near-infrared spectroscopy. CP stimulation during the isometric contraction diminished the magnitude of the contraction-induced decrease of blood volume when compared to the trials without CP stimulation. However, in the immediate post-contraction period while the CP stimulation was still in place , no increase in blood volume above the usual post-contraction hyperaemia was evident.
Once the CP stimulation had been removed, there was a clear decrease faster return to baseline in the vasodilation occurring in the post-contraction period. This diminished period of vasodilation occurred in spite of the fact that the vascular resistance blood pressure and heart rate were still substantially elevated by the CP effect during this same period.
These data suggest that the strong CP stimulation produced a biphasic response. First, there was an early-onset strong vasodilation during CP , which was followed by a period of diminished vasodilation, suggesting that an active, but delayed, vasoconstrictive drive may be induced by the CP stimulus. Extant research focuses on parent self-reported experience or observable behavioural responses. Physiological responding, such as heart rate HR and heart rate variability HRV , is critical to the experience and regulation of emotions and provides a complementary perspective on parent experience; yet, it is scarcely assessed.
Consequently, considering previous experience with pain and resting HRV levels are relevant to understanding parent physiological responses before and after child pain. Objective Individuals with chronic fatigue syndrome CFS experience many pain symptoms. The present study examined whether pain and fatigue ratings and pain threshold and tolerance levels for cold pain differed between twins with CFS and their cotwins without CFS.
Design Cotwin control design to assess cold pain sensitivity, pain, and fatigue in monozygotic twins discordant for CFS. Results Although cold pain threshold and tolerance levels were slightly lower in twins with CFS than their cotwins without CFS, these differences failed to reach statistical significance.
This study evaluated the effect of intravenous infusion of a non-selective alpha-adrenergic blocking agent on masseter muscle haemodynamics induced by 4 degrees C cold pressor stimulation CPS of the right foot and ankle, which reportedly evokes a rapidly increasing sympathetic nerve activity in human skeletal muscle. Nine healthy non-smoking males mean age The haemoglobin Hb concentration in the right masseter was continuously recorded by non-invasive, near-infrared spectroscopy. The experiment involved the following sequence: The saline and drug trials each involved continuous recording for 1 min before, 2 min during and 5 min after the CPS.
This infusion was begun 15 min before baseline recording and participants were not aware which solution saline or phentolamine was being infused. For the MVC trial, each participant performed a sec MVC of his jaw-closing muscles followed by a min rest between each trial. The individual Hb data were adjusted so that the baseline at the beginning of the experiment was equal to zero and all data were normalized as a percentage of the individual's highest absolute Hb change seen after the MVC. The mean baseline Hb concentrations 1 min before CPS were significantly higher in the alpha-blocker trial When the propellants in a liquid rocket engine burn, the rocket not only launches and moves in space, it causes forces that interact with the vehicle itself.
When these interactions occur under specific conditions, the vehicle's structures and components can become unstable. One instability of primary concern is termed pogo named after the movement of a pogo stick , in which the oscillations cycling movements cause large loads, or pressure, against the vehicle, tanks, feedlines, and engine. Marshall Space Flight Center MSFC has developed a unique test technology to understand and quantify the complex fluid movements and forces in a liquid rocket engine that contribute strongly to both engine and integrated vehicle performance and stability.
This new test technology was established in the MSFC Cold Flow Propulsion Test Complex to allow injection and measurement of scaled propellant flows and measurement of the resulting forces at multiple locations throughout the engine.
Repeatability of a cold stress test to assess cold sensitization. Non-freezing cold injury NFCI is a syndrome in which damage to peripheral tissues occurs without the tissues freezing following exposure to low ambient temperatures. To assess the test -retest reliability of a cold stress test CST used to assess cold sensitization. Thermal images were taken of the foot and hand before, immediately after and 5min after immersion of the limb in cold water for 2min.
Cold sensitization was graded by the two clinicians and the lead author. Spot temperatures from the toe and finger pads were recorded. There were 30 white and 19 black male participants.
The test -retest reliability of the CST is considered adequate for the assessment of the cold sensitization of the hands and feet of white and the hands of black healthy non-patients. The study should be repeated with patients who have suffered a NFCI.
Wire and Cable Cold Bending Test. One of the factors in assessing the applicability of wire or cable on the lunar surface is its flexibility under extreme cold conditions. Existing wire specifications did not address their mechanical behavior under cold , cryogenic temperature conditions.
Therefore tests were performed to provide this information. To assess this characteristic 35 different insulated wire and cable pieces were cold soaked in liquid nitrogen. The segments were then subjected to bending and the force was recorded. Any failure of the insulation or jacketing was also documented for each sample tested. The bending force tests were performed at room temperature to provide a comparison to the change in force needed to bend the samples due to the low temperature conditions.
The results from the bending tests were plotted and showed how various types of insulated wire and cable responded to bending under cold conditions. These results were then used to estimate the torque needed to unroll the wire under these low temperature conditions. A propulsion cold flow test system, representing an early flight design of the propulsion system, has been fabricated.
The primary objective of the cold flow test is to simulate the Resource Prospector propulsion system operation through water flow testing and obtain data for anchoring analytical models. This paper has 72 citations. From This Paper Figures, tables, and topics from this paper.
Topics Discussed in This Paper Hypertensive disease. Citations Publications citing this paper. Showing of 16 extracted citations. Adversity of prolonged extreme cold exposure among adult clients diagnosed with coronary artery diseases: Dimaya , Mae M.
The cold pressor test in interictal migraine patients — different parasympathetic pupillary response indicates dysbalance of the cranial autonomic nervous system Ozan E Eren , R. Schwartz , Marcos L. Dietary nitrate supplementation and blood pressure responsiveness in human aging Aaron Schneider. Cardiovascular autonomic dysfunction in patients with multiple sclerosis Students Paul Dendale.
Citation Statistics 73 Citations 0 10 20 30 '12 '14 '16 ' Glaucoma is a neurodegenerative disease that mainly affects the retinal ganglion cells. The function of these cells can be examined objectively using the steady-state PERG. The CPT is a strong and standardized stressor that evokes a cardiovascular response. The CPT was first introduced by Hines and Brown in 19 and was applied in cardiovascular research as well as in research on stress and pain.
The CPT causes arterial vasoconstriction and an increase in blood pressure by activating the sympathetic autonomic nervous system. In the present study, the CPT procedure was modified by adding a following warming-up period to evoke a strong change of blood pressure and retinal blood flow followed by a recovery to baseline conditions during the warming-up phase. In agreement with previous data, 2 , 5 , 31 — 35 we found that PERG amplitudes are reduced in glaucoma patients. In a long-term observational study, Bach et al.
The reduced signal may be caused by dysfunctional ganglion cells. Ventura 2 and North 31 claim that there is preliminary ganglion cell dysfunction prior to apoptosis possibly related to remodeling processes with shrinking of the dendritic branches and a functional reduction in neuronal sensitivity.
As mentioned by North et al. Our results show a continuous decrease of PERG amplitude depending on the degree of retinal ganglion cell dysfunction. This supports the hypothesis that vascular dysregulation plays an important role in the pathogenesis of NTG. Alternatively, the reaction of the arterial blood pressure to the CPT may be altered in glaucoma patients. Several studies showed disturbed neurovascular coupling in patients with NTG. In this study, we found a statistically significant decrease of amplitude during warming-up condition after cold provocation in NTG subjects, which was not found in healthy-, OHT- and HTG-subjects.
Possibly, a disturbed response to CPT leads to larger amplitude changes after provocation tests. Pattern electroretinogram latency differences between normals and glaucoma are less frequently reported. We excluded this influence by matching the groups by age. In this study, no statistically significant latency difference during baseline conditions was found between normals and glaucoma subjects.
This may be explained by a faster generation of the PERG signal because of a transient increase of retinal blood flow as a reaction to temperature stimuli. Porciatti and Ventura 34 proposes that the increase latency was caused by a slower generation of the electrical signal in activated neurons. Conversely, a CPT-induced latency decrease suggests a faster electrical activity signal possibly caused by an increased retinal blood flow.
In conclusion, our data confirm that PERG amplitude is significantly smaller in glaucoma subjects during normal test conditions and remains reduced during a simultaneous CPT. In the NTG subgroup, the amplitude changed in the warming-up phase of our modified CPT protocol, possibly as a result of a disturbed vasomotoric reaction. In all subjects, CPT possibly leads to a decreased latency. In this regard, further electrophysiological studies combined with perfusion influencing tests could help to learn more about the vascular pathogenic component of glaucoma.
The present work was performed in fulfillment of the requirements for obtaining the degree Dr. La Mancusa , None; F. Horn , None; J. Kremers , None; C. Huchzermeyer , None; M. Rudolph , None; A.
Invest Ophthalmol Vis Sci. Ventura LM Porciatti V. Pattern electroretinogram in glaucoma. Photopic negative response versus pattern electroretinogram in early glaucoma. Pattern electroretinogram abnormality and glaucoma. Bach M Speidel-Fiaux A. Pattern electroretinogram in glaucoma and ocular hypertension.
Coleman AL Miglior S. Risk factors for glaucoma onset and progression. Influencing ocular blood flow in glaucoma patients: Flammer J Mozaffarieh M. What is the present pathogenetic concept of glaucomatous optic neuropathy?
Optic nerve blood-flow abnormalities in glaucoma. Prog Retin Eye Res. Abnormal systemic and ocular vascular response to temperature provocation in primary open-angle glaucoma patients: Visual evoked potentials of the blue-sensitive pathway under cold provocation in normals and glaucomas.
Autoregulation in the ocular and cerebral arteries during the cold pressor test and handgrip exercise. Eur J Appl Physiol. Cold pressor test and retinal capillary perfusion in vasospastic subjects with and without capsular glaucoma a preliminary study. Retinal blood flow autoregulation in response to an acute increase in blood pressure. Retinal artery response to acute systemic blood pressure increase during cold pressor test in humans.
Response of blood flow to warm and cold in normal and low-tension glaucoma patients. Differential physiological effects during tonic painful hand immersion tests using hot and ice water.
The Erlangen Glaucoma Registry:
Cold stress and the cold pressor test.
Evaluation of Physiological Cardiovascular Reactivity to Cold Pressor. Stress Test. Farhana Ahad1*, Ashfaq-ul-Hassan2, Tariq A. Bhat3, Irfan. As a method of experimental pain induction, the cold pressor test is thought to mimic the effects of chronic conditions effectively. A survey of previous studies. Cold Stress Testing in Medical Thermal Imaging. Robert Glenn Schwartz1, Marcos Brioschi2, Tashof Bernton3, Jim Campbell4, Carol Chandler5, Jan Crawford6.