scholarly journals Decreased otolith-mediated vestibular response in 25 astronauts induced by long-duration spaceflight

2016 ◽  
Vol 115 (6) ◽  
pp. 3045-3051 ◽  
Author(s):  
Emma Hallgren ◽  
Ludmila Kornilova ◽  
Erik Fransen ◽  
Dmitrii Glukhikh ◽  
Steven T. Moore ◽  
...  

The information coming from the vestibular otolith organs is important for the brain when reflexively making appropriate visual and spinal corrections to maintain balance. Symptoms related to failed balance control and navigation are commonly observed in astronauts returning from space. To investigate the effect of microgravity exposure on the otoliths, we studied the otolith-mediated responses elicited by centrifugation in a group of 25 astronauts before and after 6 mo of spaceflight. Ocular counterrolling (OCR) is an otolith-driven reflex that is sensitive to head tilt with regard to gravity and tilts of the gravito-inertial acceleration vector during centrifugation. When comparing pre- and postflight OCR, we found a statistically significant decrease of the OCR response upon return. Nine days after return, the OCR was back at preflight level, indicating a full recovery. Our large study sample allows for more general physiological conclusions about the effect of prolonged microgravity on the otolith system. A deconditioned otolith system is thought to be the cause of several of the negative effects seen in returning astronauts, such as spatial disorientation and orthostatic intolerance. This knowledge should be taken into account for future long-term space missions.

2008 ◽  
Vol 18 (2-3) ◽  
pp. 97-105
Author(s):  
Suzanne A.E. Nooij ◽  
Jelte E. Bos ◽  
Eric L. Groen

Adaptation to a novel gravitational state involves adaptation of vestibular mediated responses, in particular those mediated by the otolith organs. The present paper investigates whether the orientation of Listing's plane, which is under control of otolith signals, is affected by sustained exposure to hypergravity. Subjects were exposed to four G-loads differing in duration (45 or 90 min) and magnitude (2 or 3G). During centrifugation subjects were in a supine position, directing the gravito-inertial acceleration along the naso-occipetal axis. We determined the orientation of Listing's plane before and after each centrifuge run, with the head erect and tilted in pitch. Head tilt in pitch induced a counter-pitch of Listing's plane, which was found to be less pronounced after centrifugation. In addition, exposure to 3G for 90~min induced a small backward tilt of Listing's plane compared to the pretest orientation (head erect). In order to explain these results a hypothesis is discussed, proposing that the orientation of Listing's plane in the head is governed by a head fixed orientation vector that is modulated by the direction of gravity relative to the head. Sustained centrifugation is proposed to decrease this gravitational modulation, leading to the effects observed. This could reflect a shift towards a more body centered frame of reference.


1989 ◽  
Vol 66 (3) ◽  
pp. 1509-1512 ◽  
Author(s):  
V. A. Convertino ◽  
D. F. Doerr ◽  
S. L. Stein

Increased leg venous compliance may contribute to postflight orthostatic intolerance in astronauts. We reported that leg compliance was inversely related to the size of the muscle compartment. The purpose of this study was to test the hypothesis that reduced muscle compartment after long-duration exposure to microgravity would cause increased leg compliance. Eight men, 31–45 yr old, were measured for vascular compliance of the calf and serial circumferences of the calf before and after 30 days of continuous 6 degrees head-down bed rest. Cross-sectional areas (CSA) of muscle, fat, and bone compartments in the calf were determined before and after bed rest by computed tomography. From before to after bed rest, calculated calf volume (cm3) decreased (P less than 0.05) from 1,682 +/- 83 to 1,516 +/- 76. Calf muscle compartment CSA (cm2) also decreased (P less than 0.05) from 74.2 +/- 3.6 to 70.6 +/- 3.4; calf compliance (ml.100 ml-1.mmHg-1.100) increased (P less than 0.05) from 3.9 +/- .7 to 4.9 +/- .5. The percent change in calf compliance after bed rest was significantly correlated with changes in calf muscle compartment CSA (r = 0.72, P less than 0.05). The increased leg compliance observed after exposure to simulated microgravity can be partially explained by reduced muscle compartment. Countermeasures designed to minimize muscle atrophy in the lower extremities may be effective in ameliorating increased venous compliance and orthostatic intolerance after spaceflight.


Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 642
Author(s):  
Bianca Brix ◽  
Olivier White ◽  
Christian Ure ◽  
Gert Apich ◽  
Paul Simon ◽  
...  

Background: Lymphedema arises due to a malfunction of the lymphatic system, leading to extensive tissue swelling. Complete decongestive therapy (CDT), which is a physical therapy lasting for 3 weeks and includes manual lymphatic drainages (MLD), leads to fluid mobilization and increases in plasma volume. Here, we investigated hemodynamic responses induced by these fluid shifts due to CDT and MLD. Methods: Hemodynamic parameters were assessed continuously during a sit-to-stand test (5 min baseline, 5 min of standing, and 5 min of recovery). This intervention was repeated on days 1, 2, 7, 14, and 21 of CDT, before and after MLD. Volume regulatory hormones were assessed in plasma samples. Results: A total number of 13 patients took part in this investigation. Resting diastolic blood pressure significantly decreased over three weeks of CDT (p = 0.048). No changes in baseline values were shown due to MLD. However, MLD led to a significant decrease in heart rate during orthostatic loading over all epochs on therapy day 14, as well as day 21. Volume regulatory hormones did not show changes over lymphedema therapy. Conclusion: We did not observe any signs of orthostatic hypotension at rest, as well as during to CDT, indicating that lymphedema patients do not display an elevated risk of orthostatic intolerance. Although baseline hemodynamics were not affected, MLD has shown to have potential beneficial effects on hemodynamic responses to a sit-to-stand test in patients undergoing lymphedema therapy.


2018 ◽  
Vol 23 (5) ◽  
pp. 298-308 ◽  
Author(s):  
Dominique Vibert ◽  
John H.J. Allum ◽  
Martin Kompis ◽  
Simona Wiedmer ◽  
Christof Stieger ◽  
...  

The aim of this study was to investigate changes in balance control for stance and gait tasks in patients 2 years before and after vestibular neurectomy (VN) performed to alleviate intractable Meniere’s disease. Amplitudes of trunk sway in roll and pitch directions were measured for stance and gait tasks in 19 patients using gyroscopes mounted at the lower-back. Measurements before VN and 2 years later were compared to those of healthy age-matched controls (HC). We also examined if changes in trunk sway amplitudes were correlated with patients’ subjective assessment of disability using the AAO-HNS scale. For patients with low AAO-HNS scores 0–2 (n = 14), trunk roll and pitch sway velocities, standing eyes closed on foam, increased 2 years post VN compared to HC values (p < 0.01). Trunk sway amplitudes remained at levels of HC for simple gait tasks, but task durations were longer and therefore gait slower. For complex gait tasks (stairs), balance control remained impaired at 2 years. In patients with AAO-HNS high scores level 6 (n = 5), balance control remained abnormal, compared to HC, 2 years postoperatively for all stance, several simple and all complex gait tasks. Trunk sway in the pitch and roll directions for stance tasks was correlated with clinical (AAO-HNS) scores (p ≤ 0.05). These results indicate that VN leads to chronic balance problems for stance and complex gait tasks. The problems are greater for patients with high compared to low AAO-HNS scores, thereby explaining the different symptoms reported by these patients. The lack of balance recovery in VN patients to levels of HCs after 2 years contrasts with the 3 months average recovery period for acute vestibular neuritis patients and is indicative of the effects of neurectomy on central compensation processes.


2004 ◽  
Vol 52 ◽  
pp. S384-S385
Author(s):  
S. M. Grenon ◽  
N. Sheynberg ◽  
X. Xiao ◽  
C. D. Ramsdell ◽  
S. Hurwitz ◽  
...  

2004 ◽  
Vol 96 (6) ◽  
pp. 2301-2316 ◽  
Author(s):  
Richard C. Fitzpatrick ◽  
Brian L. Day

Galvanic vestibular stimulation (GVS) is a simple, safe, and specific way to elicit vestibular reflexes. Yet, despite a long history, it has only recently found popularity as a research tool and is rarely used clinically. The obstacle to advancing and exploiting GVS is that we cannot interpret the evoked responses with certainty because we do not understand how the stimulus acts as an input to the system. This paper examines the electrophysiology and anatomy of the vestibular organs and the effects of GVS on human balance control and develops a model that explains the observed balance responses. These responses are large and highly organized over all body segments and adapt to postural and balance requirements. To achieve this, neurons in the vestibular nuclei receive convergent signals from all vestibular receptors and somatosensory and cortical inputs. GVS sway responses are affected by other sources of information about balance but can appear as the sum of otolithic and semicircular canal responses. Electrophysiological studies showing similar activation of primary afferents from the otolith organs and canals and their convergence in the vestibular nuclei support this. On the basis of the morphology of the cristae and the alignment of the semicircular canals in the skull, rotational vectors calculated for every mode of GVS agree with the observed sway. However, vector summation of signals from all utricular afferents does not explain the observed sway. Thus we propose the hypothesis that the otolithic component of the balance response originates from only the pars medialis of the utricular macula.


2021 ◽  
Vol 11 (11) ◽  
pp. 715
Author(s):  
Francesco Faenza ◽  
Claudia Canali ◽  
Michele Colajanni ◽  
Antonella Carbonaro

In the last few years, several initiatives based on extracurricular activities have been organized in many countries around the world, with the aim to reduce the digital gender gap in STEM (Science, Technology, Engineering, Math) fields. Among them, the Digital Girls summer camp, organized every year since 2014 by two Italian universities with the aim to attract female students to ICT (Information and Communication Technologies) disciplines, represents quite a unique initiative for its characteristics of long-duration (3–4 entire weeks) and complete gratuitousness for the participants. The COVID-19 emergency imposed severe changes to such activities, that had to be modified and carried out in the online mode as a consequence of social distancing. However, on one hand, the general lack of high-quality evaluations of these initiatives hinders the possibility to understand the actual impact of extracurricular activities on the future academic choices of the participants. On the other hand, the availability of data collected over different editions of Digital Girls has allowed us to analyze the summer camp impact and to evaluate the pros and cons of in-presence and online activities. The main contribution of this paper is twofold. First, we present an overview of existing experiences, at the national (Italian) and international levels, to increase female participation in integrated STEM and ICT fields. Second, we analyze how summer camp participation can influence girls’ future academic choices, with specific attention to ICT-related disciplines. In particular, the collection of a significant amount of data through anonymous surveys conducted before and after the camp activities over the two editions allowed us to evidence the different impacts of in-presence and online extracurricular activities.


2018 ◽  
Vol 6 (11) ◽  
pp. 95
Author(s):  
Muzaffer Selcuk ◽  
Vedat Cinar ◽  
Mucahit Sarikaya ◽  
Salih Oner

This study aims to observe the possible negative effects that might occur on bio-chemistry and hemogram values of tennis players during the intense competition period by comparing the blood values of pre-competition period with 10 days of intense exercise. Blood samples were obtained from tennis team players who do not have any specific health problems and who study in university and regularly exercise. Mean age of the athletes are 22,40 ± 3,20 years and mean height is 179,83 ± 7,57 cm. This study is performed with 14 volunteer tennis players. Blood samples are obtained during the first day of the intense exercise program after the exercise, last day of the exercises and also right after the exercises. As per the obtained data, descriptive statistics are run (mean and standard deviation) and in order to compare the values of before and after the 10 days of intense exercise, Wilcoxon two related sample test was used. As per the results of the blood tests from before and after the exercise period, it is seen that values such as AST, ALT, MCH, MCHC and CK showed statistical significance (P<0.05). The athletes who prepared for the competitions with these values showed positive increases in bio-chemistry and hemogram values.


2020 ◽  
Author(s):  
Ali osali ◽  
Alireza Rostami

Abstract BackgroundThe purpose of this study was to investigate the effect of 12 months of aerobic exercise combining stachys lavandulifolia (S. lavandulifolia) consumption on anxiety, Metabolic Syndrome profiles and antioxidant defense (Glutathione) and lipid peroxidation (Malondialdehyde) in 50-65 years old women with syndrome metabolic.Methods48 women with syndrome Metabolic were randomly divided into four groups: exercise (n=12), exercise+S. lavandulifolia (n=12), S. lavandulifolia (n=12) and control group (n=12). S. lavandulifolia groups consumed 3 g aerial parts of S. lavandulifolia daily. Training groups performed an exercise protocol of aerobic exercise for 12 months (three sessions per week). Blood samples were obtained before and after training period for antioxidant indicators and lipid degradation measurement. Also, Beck anxiety questionnaire used for evaluating levels of anxiety. T-test and one-way analysis of variance were used for the evaluation of within-group and between-group differences, respectively.ResultsA significant increase was observed in serum levels of Malondialdehyde (P =0.004), Catalase indexes (Pvalue= 0.01), and Glutathione (P=0.001) in the training group and S. lavandulifolia groups after 12 months. Body weight, BMI, and SBP and Anexiety was decreased significantly greater in exercise +S. lavandulifolia group compared to control, exercise and S. lavandulifolia groups (P=0.001)ConclusionAnxiolytic effect and Anti-Oxidative Stress Activity was seen, so taking S. lavandulifolia along with exercises may have beneficial effects on reinforcement the antioxidant system and prevention of anxiety and The negative effects of indicators related to cardiovascular disease in women with metabolic syndrome.


2020 ◽  
Author(s):  
Quyen G To ◽  
Mitch J Duncan ◽  
Anetta Van Itallie ◽  
Corneel Vandelanotte

BACKGROUND Physical activity is an important health behavior, due to its association with many physical and mental health conditions. During distressing events, such as the COVID-19 pandemic, there is a concern that physical activity levels may be negatively impacted. However, recent studies have shown inconsistent results. Additionally, there is a lack of studies in Australia on this topic. OBJECTIVE The aim of this study is to investigate changes in physical activity reported through the 10,000 Steps program and changes in engagement with the program during the COVID-19 pandemic. METHODS Data between January 1, 2018, and June 30, 2020, from registered members of the 10,000 Steps program, which included 3,548,825 days with step data, were used. The number of daily steps were logged manually by the members or synced automatically from their activity trackers connected to the program. Measures on program usage were the number of new registered members per day, the number of newly registered organizations per day, the number of steps logged per day, and the number of step entries per day. Key dates used for comparison were as follows: the first case with symptoms in Wuhan, China; the first case reported in Australia; the implementation of a 14-day ban for noncitizens arriving in Australia from China; the start of the lockdown in Australia; and the relaxing of restrictions by the Australian Government. Wilcoxon signed-rank tests were used to test for significant differences in number of steps between subgroups, between engagement measures in 2019 versus 2020, and before and after an event. RESULTS A decrease in steps was observed after the first case in Australia was reported (1.5%; <i>P</i>=.02) and after the start of the lockdown (3.4%; <i>P</i>&lt;.001). At the time that the relaxing of restrictions started, the steps had already recovered from the lockdown. Additionally, the trends were consistent across genders and age groups. New South Wales, Australian Capital Territory, and Victoria had the greatest step reductions, with decreases of 7.0% (<i>P</i>&lt;.001), 6.2% (<i>P</i>=.02), and 4.7% (<i>P</i>&lt;.001), respectively. During the lockdown, the use of the program increased steeply. On the peak day, there were more than 9000 step entries per day, with nearly 100 million steps logged per day; in addition, more than 450 new users and more than 15 new organizations registered per day, although the numbers decreased quickly when restrictions were relaxed. On average per day, there were about 55 new registered users (<i>P</i>&lt;.001), 2 new organizations (<i>P</i>&lt;.001), 25.6 million steps (<i>P</i>&lt;.001), and 2672 log entries (<i>P</i>&lt;.001) more in 2020 compared to the same period in 2019. CONCLUSIONS The pandemic has had negative effects on steps among Australians across age groups and genders. However, the effect was relatively small, with steps recovering quickly after the lockdown. There was a large increase in program usage during the pandemic, which might help minimize the health impact of the lockdown and confirms the important role of physical activity programs during times of distress and lockdowns.


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