1
|
Gupta U, Baig S, Majid A, Bell SM. The neurology of space flight; How does space flight effect the human nervous system? LIFE SCIENCES IN SPACE RESEARCH 2023; 36:105-115. [PMID: 36682819 DOI: 10.1016/j.lssr.2022.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 06/17/2023]
Abstract
RATIONALE AND HYPOTHESIS Advancements in technology, human adaptability, and funding have increased space exploration and in turn commercial spaceflight. Corporations such as Space X and Blue Origin are exploring methods to make space tourism possible. This could lead to an increase in the number of patients presenting with neurological diseases associated with spaceflight. Therefore, a comprehensive understanding of spaceflight stressors is required to manage neurological disease in high-risk individuals. OBJECTIVES This review aims to describe the neurological effects of spaceflight and to assess countermeasures such as pre-flight prophylaxis, training, and possible therapeutics to reduce long-term effects. METHODOLOGY A literature search was performed for experimental studies conducted in astronauts and in animal models that simulated the space environment. Many studies, however, only discussed these with scientific reasoning and did not include any experimental methods. Relevant studies were identified through searching research databases such as PubMed and Google Scholar. No inclusion or exclusion criteria were used. FINDINGS Analysis of these studies provided a holistic understanding of the acute and chronic neurological changes that occur during space flight. Astronauts are exposed to hazards that include microgravity, cosmic radiation, hypercapnia, isolation, confinement and disrupted circadian rhythms. Microgravity, the absence of a gravitational force, is linked to disturbances in the vestibular system, intracranial and intraocular pressures. Furthermore, microgravity affects near field vision as part of the spaceflight-associated neuro-ocular syndrome. Exposure to cosmic radiation can increase the risk of neurodegenerative conditions and malignancies. It is estimated that cosmic radiation has significantly higher ionising capabilities than the ionising radiation used in medicine. Space travel also has potential benefits to the nervous system, including psychological development and effects on learning and memory. Future work needs to focus on how we can compare a current astronaut to a future space tourist. Potentially the physiological and psychological stresses of space flight might lead to neurological complications in future space travellers that do not have the physiological reserve of current astronauts.
Collapse
Affiliation(s)
- Udit Gupta
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield and S10 2HQ, United Kingdom
| | - Sheharyar Baig
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield and S10 2HQ, United Kingdom; Department of Clinical Neurology, Royal Hallamshire Hospital, Glossop Road, Sheffield, United Kingdom
| | - Arshad Majid
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield and S10 2HQ, United Kingdom; Department of Clinical Neurology, Royal Hallamshire Hospital, Glossop Road, Sheffield, United Kingdom
| | - Simon M Bell
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield and S10 2HQ, United Kingdom; Department of Clinical Neurology, Royal Hallamshire Hospital, Glossop Road, Sheffield, United Kingdom.
| |
Collapse
|
2
|
Abstract
BACKGROUND Motion sickness is a syndrome that occurs as a result of passive body movement in response to actual motion, or the illusion of motion when exposed to virtual and moving visual environments. The most common symptoms are nausea and vomiting. Antihistamines have been used in the management of motion sickness for decades, however studies have shown conflicting results regarding their efficacy. OBJECTIVES To assess the effectiveness of antihistamines in the prevention and treatment of motion sickness in adults and children. SEARCH METHODS The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials; Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 7 December 2021. SELECTION CRITERIA Randomised controlled trials (RCTs) in susceptible adults and children in whom motion sickness was induced under natural conditions such as air, sea and land transportation. We also included studies in which motion sickness was induced under experimental conditions (analysed separately). Antihistamines were included regardless of class, route or dosage and compared to no treatment, placebo or any other pharmacological or non-pharmacological interventions. DATA COLLECTION AND ANALYSIS We used standard Cochrane methods. Our primary outcomes were 1) the proportion of susceptible participants who did not experience any motion sickness symptoms; 2) the proportion of susceptible participants who experienced a reduction or resolution of existing symptoms. Secondary outcomes were 1) physiological measures (heart rate, core temperature and gastric tachyarrhythmia (electrogastrography)) and 2) adverse effects (sedation, impaired cognition, blurred vision). We used GRADE to assess the certainty of the evidence for each outcome. MAIN RESULTS We included nine RCTs (658 participants). Studies were conducted across seven countries, with an overall age range of 16 to 55 years. Motion sickness was induced naturally in six studies and experimentally in four studies (rotating chair). All the naturally induced studies only evaluated first-generation antihistamines (cinnarizine and dimenhydrinate). Risk of bias across the studies varied, with mostly low risk for random sequence generation and allocation concealment, and mostly high risk for selective reporting. Only the experimentally induced studies measured physiological parameters and only the naturally induced studies evaluated adverse effects. There were no studies that clearly assessed the paediatric population. Antihistamines versus placebo or no treatment Antihistamines are probably more effective than placebo at preventing motion sickness symptoms under natural conditions (symptoms prevented: 25% placebo; 40% antihistamines) (risk ratio (RR) 1.81, 95% confidence interval (CI) 1.23 to 2.66; 3 studies; 240 participants) (moderate-certainty). The evidence is very uncertain about the effect of antihistamines on preventing motion sickness under experimental conditions (standardised mean difference (SMD) 0.32, 95% CI -0.18 to 0.83; 2 studies; 62 participants) (very low-certainty). No studies reported results on the resolution of existing motion sickness symptoms. Antihistamines may result in little or no difference in gastric tachyarrhythmia under experimental conditions (mean difference (MD) -2.2, 95% CI -11.71 to 7.31; 1 study; 42 participants) (low-certainty). No studies reported results for any other physiological measures. When compared to placebo, antihistamines may be more likely to cause sedation (sedation: 44% placebo; 66% antihistamines) (RR 1.51, 95% CI 1.12 to 2.02; 2 studies; 190 participants) (low-certainty); they may result in little or no difference in blurred vision (blurred vision: 12.5% placebo; 14% antihistamines) (RR 1.14, 95% CI 0.53 to 2.48; 2 studies; 190 participants) (low-certainty); and they may result in little or no difference in terms of impaired cognition (impaired cognition: 33% placebo; 29% antihistamines) (RR 0.89, 95% CI 0.58 to 1.38; 2 studies; 190 participants) (low-certainty). Antihistamines versus scopolamine The evidence is very uncertain about the effect of antihistamines on preventing motion sickness under natural conditions when compared to scopolamine (symptoms prevented: 81% scopolamine; 71% antihistamines) (RR 0.89, 95% CI 0.68 to 1.16; 2 studies; 71 participants) (very low-certainty). No studies were performed under experimental conditions. No studies reported results on the resolution of existing motion sickness symptoms. The evidence is very uncertain about the effect of antihistamines on heart rate under natural conditions (narrative report, 1 study; 20 participants; "No difference in pulse frequency"; very low-certainty). No studies reported results for any other physiological measures. When compared to scopolamine, the evidence is very uncertain about the effect of antihistamines on sedation (sedation: 21% scopolamine; 30% antihistamines) (RR 0.82, 95% CI 0.07 to 9.25; 2 studies; 90 participants) (very low-certainty) and on blurred vision (narrative report: not a significant difference; 1 study; 51 participants; very low-certainty). No studies evaluated impaired cognition. Antihistamines versus antiemetics Antihistamines may result in little or no difference in the prevention of motion sickness under experimental conditions (MD -0.20, 95% CI -10.91 to 10.51; 1 study; 42 participants) (low-certainty). The evidence is of low certainty due to imprecision as the sample size is small and the confidence interval crosses the line of no effect. No studies assessed the effects of antihistamines versus antiemetics under natural conditions. No studies reported results on the resolution of existing motion sickness symptoms. Antihistamines may result in little or no difference in gastric tachyarrhythmia (MD 4.56, 95% CI -3.49 to 12.61; 1 study; 42 participants) (low-certainty). No studies reported results for any other physiological measures. No studies evaluated sedation, impaired cognition or blurred vision. One study reported physiological data for this outcome, evaluating gastric tachyarrhythmia specifically. Antihistamines may result in little or no difference in gastric tachyarrhythmia (MD 4.56, 95% CI -3.49 to 12.61; 1 study; 42 participants; low-certainty evidence). This evidence is of low certainty due to imprecision as the sample size is small and the confidence interval crosses the line of no effect. Antihistamines versus acupuncture The evidence is very uncertain about the effects of antihistamines on the prevention of motion sickness under experimental conditions when compared to acupuncture (RR 1.32, 95% CI 1.12 to 1.57; 1 study; 100 participants) (very low-certainty). This study did not assess the prevention of motion sickness under natural conditions, nor the resolution of existing motion sickness symptoms. There was no study performed under natural conditions. Physiological measures and adverse effects were not reported. AUTHORS' CONCLUSIONS There is probably a reduction in the risk of developing motion sickness symptoms under naturally occurring conditions of motion when using first-generation antihistamines, in motion sickness-susceptible adults, compared to placebo. Antihistamines may be more likely to cause sedation when compared to placebo. No studies evaluated the treatment of existing motion sickness, and there are few data on the effect of antihistamines in children. The evidence for all other outcomes and comparisons (versus scopolamine, antiemetics and acupuncture) was of low or very low certainty and we are therefore uncertain about these effects of antihistamines.
Collapse
Affiliation(s)
- Nadine Karrim
- Institute of Research into Space Health and Astronaut Development, International Centre for Astronautical Development, Durban, South Africa
| | - Ryan Byrne
- Institute of Research into Space Health and Astronaut Development, International Centre for Astronautical Development, Dublin, Ireland
| | | | - Yougan Saman
- ENT Department, University Hospitals of Leicester NHS Trust, Leicester, UK
- Department of Neuroscience Psychology and Behaviour, University of Leicester, Leicester, UK
| |
Collapse
|
3
|
Mucci V, Jacquemyn Y, Van Ombergen A, Van de Heyning PH, Browne CJ. A new theory on GABA and Calcitonin Gene-Related Peptide involvement in Mal de Debarquement Syndrome predisposition factors and pathophysiology. Med Hypotheses 2018; 120:128-134. [PMID: 30220332 DOI: 10.1016/j.mehy.2018.08.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Mal de Debarquement Syndrome (MdDS) is a condition characterized by a sensation of motion in the absence of a stimulus, which presents with two subtypes depending on the onset: Motion-Triggered, and Spontaneous or Non-Motion Triggered. MdDS predominantly affects women around 40-50 years of age and a high number of patients report associated disorders, such as migraine and depression. The pathophysiology of MdDS is unclear, as is whether there are predisposing factors that make individuals more vulnerable to developing the condition. Hormonal changes in women similarly to what observed in migraineous patients, as well as depression disorder, have been examined as potential key factors for developing MdDS. Studies on migraine and depression have revealed correlations with hormonal fluctuations in females as well as aberrant levels of some key neurotransmitters such as Gamma-Aminobutyric Acid (GABA) and inflammatory neuropeptides like Calcitonin Gene-Related Peptide (CGRP). Consequently, this manuscript aims to propose a new hypothesis on the predisposing factors for MdDS and a new concept that could contribute to the understanding of its pathophysiology. NEW HYPOTHESIS Recent findings have demonstrated a role for hormonal influences in MdDS patients, similar to previous observations in patients with depression and migraine. We hypothesize the involvement of gonadal hormones and aberrant neurotransmitter levels, including the GABAergic and serotonergic systems, in MdDS pathophysiology. Our theory is that certain individuals are more vulnerable to develop MdDS during specific gonadal hormonal phases. Furthermore, we hypothesize that it may be possible to identify these individuals by measurement of an existing imbalance of these neurotransmitters or inflammatory neuropeptides like CGRP. FURTHER EVALUATION OF THE HYPOTHESIS According to one theory, MdDS is considered as a maladaptation of the Vestibular Ocular Reflex (VOR) and velocity storage. When considering this theory, it is essential to highlight that the brainstem nuclei involved in the VOR and the velocity storage include GABAb sensitive neurons, which appear to produce inhibitory control of velocity storage. Responses of these GABAb sensitive neurons are also modulated by CGRP. Thus an alteration of the GABAergic network by imbalances of inhibitory neurotransmitters or CGRP could influence signal integration in the velocity storage system and therefore be directly involved in MdDS pathophysiology. CONSEQUENCE OF THE HYPOTHESIS AND FUTURE STUDIES A hormonal and neurotransmitter imbalance may act to predispose individuals in developing MdDS. Future studies should focus on the hormonal influences on neurotransmitters (e.g. GABA) and on the trial of CGRP antagonist drugs for the treatment of MdDS patients.
Collapse
Affiliation(s)
- Viviana Mucci
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1 (D.T.430), 2610 Wilrijk, Antwerp, Belgium; Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Antwerp University, Wilrijkstraat 10 (route 71 - 125), 2650 Edegem, Antwerp, Belgium; Department of Physics, Faculty of Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
| | - Yves Jacquemyn
- Department of Gynaecology, Antwerp University Hospital, University of Antwerp, Wilrijkstraat 10, 2650, Edegem, Antwerp, Belgium
| | - Angelique Van Ombergen
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1 (D.T.430), 2610 Wilrijk, Antwerp, Belgium; Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Antwerp University, Wilrijkstraat 10 (route 71 - 125), 2650 Edegem, Antwerp, Belgium; Department of Physics, Faculty of Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Paul H Van de Heyning
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1 (D.T.430), 2610 Wilrijk, Antwerp, Belgium; Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Antwerp University, Wilrijkstraat 10 (route 71 - 125), 2650 Edegem, Antwerp, Belgium
| | - Cherylea J Browne
- School of Science and Health, (Room 21.1.12), Campbelltown Campus, Western Sydney University, NSW 2560, Australia; Translational Neuroscience Facility, School of Medical Sciences, Wallace Wurth Building (Room 316, Level 3), UNSW, Sydney, NSW 2052, Australia
| |
Collapse
|
4
|
Diaz-Artiles A, Priesol AJ, Clark TK, Sherwood DP, Oman CM, Young LR, Karmali F. The Impact of Oral Promethazine on Human Whole-Body Motion Perceptual Thresholds. J Assoc Res Otolaryngol 2017; 18:581-590. [PMID: 28439720 DOI: 10.1007/s10162-017-0622-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/22/2017] [Indexed: 11/25/2022] Open
Abstract
Despite the widespread treatment of motion sickness symptoms using drugs and the involvement of the vestibular system in motion sickness, little is known about the effects of anti-motion sickness drugs on vestibular perception. In particular, the impact of oral promethazine, widely used for treating motion sickness, on vestibular perceptual thresholds has not previously been quantified. We examined whether promethazine (25 mg) alters vestibular perceptual thresholds in a counterbalanced, double-blind, within-subject study. Thresholds were determined using a direction recognition task (left vs. right) for whole-body yaw rotation, y-translation (interaural), and roll tilt passive, self-motions. Roll tilt thresholds were 31 % higher after ingestion of promethazine (P = 0.005). There were no statistically significant changes in yaw rotation and y-translation thresholds. This worsening of precision could have functional implications, e.g., during driving, bicycling, and piloting tasks. Differing results from some past studies of promethazine on the vestibulo-ocular reflex emphasize the need to study motion perception in addition to motor responses.
Collapse
Affiliation(s)
- Ana Diaz-Artiles
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA.
- Aeronautics & Astronautics Department, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Adrian J Priesol
- Massachusetts Eye and Ear Infirmary, Boston, MA, USA
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, USA
| | - Torin K Clark
- Aerospace Engineering Sciences, University of Colorado at Boulder, Boulder, CO, USA
| | - David P Sherwood
- Aeronautics & Astronautics Department, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Charles M Oman
- Aeronautics & Astronautics Department, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Laurence R Young
- Aeronautics & Astronautics Department, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Faisal Karmali
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
5
|
Shimizu N, Wood S, Kushiro K, Perachio A, Makishima T. The role of GABAB receptors in the vestibular oculomotor system in mice. Behav Brain Res 2016; 302:152-9. [PMID: 26778789 DOI: 10.1016/j.bbr.2016.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 11/28/2022]
Abstract
Systemic administration of a gamma-amino butyric acid type B (GABAB) receptor agonist, baclofen, affects various physiological and psychological processes. To date, the effects on oculomotor system have been well characterized in primates, however those in mice have not been explored. In this study, we investigated the effects of baclofen focusing on vestibular-related eye movements. Two rotational paradigms, i.e. sinusoidal rotation and counter rotation were employed to stimulate semicircular canals and otolith organs in the inner ear. Experimental conditions (dosage, routes and onset of recording) were determined based on the prior studies exploring the behavioral effects of baclofen in mice. With an increase in dosage, both canal and otolith induced ocular responses were gradually affected. There was a clear distinction in the drug sensitivity showing that eye movements derived from direct vestibulo-ocular reflex pathways were relatively unaltered, while the responses through higher-order neural networks in the vestibular system were substantially decreased. These findings were consistent with those observed in primates suggesting a well-conserved role of GABAB receptors in the oculomotor system across frontal-eyed and lateral-eyed animals. We showed here a previously unrecognized effect of baclofen on the vestibular oculomotor function in mice. When interpreting general animal performance under the drug, the potential contribution of altered balance system should be taken into consideration.
Collapse
Affiliation(s)
- Naoki Shimizu
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
| | - Scott Wood
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA; Department of Psychology, Azusa Pacific University, Azusa California, USA
| | - Keisuke Kushiro
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Adrian Perachio
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Tomoko Makishima
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
| |
Collapse
|