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Lee JJ, Forristal MT, Harney F, Flaherty GT. Eye disease and international travel: a critical literature review and practical recommendations. J Travel Med 2023; 30:taad068. [PMID: 37191043 PMCID: PMC10289526 DOI: 10.1093/jtm/taad068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/03/2023] [Accepted: 05/05/2023] [Indexed: 05/17/2023]
Abstract
RATIONALE FOR REVIEW Eye diseases pose a significant public health and economic burden, particularly for travellers exposed to ocular hazards who may lack access to specialist eye care. This article offers an evidence-based review for travel-health practitioners, with a particular emphasis on ocular infections and trauma that are more prevalent among travellers. Providing an overview of these issues will allow travel health practitioners to comprehensively address ophthalmic considerations of travel. METHODS A systematic literature search was conducted on PubMed and Embase electronic databases, using keywords related to travel medicine and ophthalmology. Inclusion was based on the relevant contribution to epidemiology, aetiology, diagnostics, management and long-term consequences of travel-related eye conditions. The data were analysed using narrative synthesis. KEY FINDINGS This literature review highlighted that various travel-related eye conditions may occur. Travellers should be aware of the risk of travel-related ocular complications, which can arise from ocular infections, high-risk activities, high altitude and space travel. The economic and logistical challenges associated with medical tourism for ophthalmic procedures are discussed. For travellers with pre-existing eye conditions or visual impairment, careful planning may be needed to promote eye health and ensure safety of travel. CONCLUSIONS Travel medicine practitioners should have a comprehensive understanding of the major ocular risks associated with overseas travel, including eye infections, eye injuries and solar eye damage. Further research in this area can enhance overall wellness and alleviate the burden of ocular diseases on travellers. Evidence-based guidelines based on research can also improve the quality of care and prevent long-term vision problems.
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Affiliation(s)
- Jay Jun Lee
- Department of Ophthalmology, University Hospital Galway, Galway, Ireland
- Department of Ophthalmology, Temple Street Children’s University Hospital, Dublin, Ireland
| | - Mark T Forristal
- Department of Ophthalmology, University Hospital Galway, Galway, Ireland
| | - Fiona Harney
- Department of Ophthalmology, University Hospital Galway, Galway, Ireland
- School of Medicine, University of Galway, Galway, Ireland
| | - Gerard T Flaherty
- School of Medicine, University of Galway, Galway, Ireland
- School of Medicine, International Medical University, Kuala Lumpur, Malaysia
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2
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Benedetti F, Frisaldi E, Shaibani A. Thirty Years of Neuroscientific Investigation of Placebo and Nocebo: The Interesting, the Good, and the Bad. Annu Rev Pharmacol Toxicol 2021; 62:323-340. [PMID: 34460317 DOI: 10.1146/annurev-pharmtox-052120-104536] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the past 30 years there has been a surge of research on the placebo effect using a neuroscientific approach. The interesting aspects of this effort are related to the identification of several biological mechanisms of both the placebo and nocebo effects, the latter of which is defined as a negative placebo effect. Some important translational implications have emerged both in the setting of clinical trials and in routine medical practice. One of the principal contributions of neuroscience has been to draw the attention of the scientific and medical communities to the important role of psychobiological factors in therapeutic outcomes, be they drug related or not. Indeed, many biological mechanisms triggered by placebos and nocebos resemble those modulated by drugs, suggesting a possible interaction between psychological factors and drug action. Unfortunately, this new knowledge regarding placebos has the potential of being dangerously exploited by pseudoscience. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Fabrizio Benedetti
- Department of Neuroscience, University of Turin Medical School, Turin I-10125, Italy; .,Medicine and Physiology of Hypoxia, Plateau Rosà CH-3920, Switzerland
| | - Elisa Frisaldi
- Department of Neuroscience, University of Turin Medical School, Turin I-10125, Italy;
| | - Aziz Shaibani
- Nerve and Muscle Center of Texas and Baylor College of Medicine, Houston, Texas 77030, USA
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3
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Benedetti F, Amanzio M, Giovannelli F, Craigs-Brackhahn K, Shaibani A. Hypothalamic-Pituitary-Adrenal Activity in Adverse Events Reporting after Placebo Administration. Clin Pharmacol Ther 2021; 110:1349-1357. [PMID: 34365636 DOI: 10.1002/cpt.2388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/28/2021] [Indexed: 11/06/2022]
Abstract
Participants of clinical trials who receive a placebo treatment often report a variety of adverse events, sometimes called nocebo effects. The reason why these adverse events occur is not clear, and understanding the underlying mechanisms represents a challenge that is likely to improve the interpretation of clinical trials as well as medical practice. Here, we studied 192 healthy subjects who received placebo oxygen through a mask after reading (READ) or not reading (NO-READ) a list of possible adverse events of oxygen breathing: headache, chest pain, abdominal pain, and cough. The whole hypothalamus-pituitary-adrenal axis was assessed just before and right after placebo breathing by measuring the hypothalamic corticotropin-releasing hormone (CRH), pituitary adrenocorticotropic hormone (ACTH), and adrenal cortisol (COR). In addition, both state and trait anxiety were assessed. We found that 64.5% of the NO-READ group reported no adverse events, 30.2% had one, and only 5.2% had two adverse events. In contrast, only 20.8% of the READ group reported no adverse events, whereas 1, 2, 3, and 4 adverse events were reported with a frequency of 21.8%, 19.8%, 19.8%, and 17.7%, respectively. In addition, when the READ group reported three and four adverse events, CRH, ACTH, and COR were significantly increased compared to the NO-READ group, along with an increase in state anxiety scores. These data indicate that hypothalamic-pituitary-adrenal activity and state anxiety are increased in those subjects who report many adverse events after reading a list of adverse events, thus highlighting a possible neuroendocrine mechanism after placebo administration.
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Affiliation(s)
- Fabrizio Benedetti
- Neuroscience Department, University of Turin Medical School, Turin, Italy.,Medicine & Physiology of Hypoxia, Plateau Rosà, Switzerland
| | | | - Fabio Giovannelli
- Department of Neuroscience, Psychology, Drug Research and Child's Health, University of Florence, Florence, Italy
| | | | - Aziz Shaibani
- Nerve & Muscle Center of Texas, Houston, Texas, USA.,Baylor College of Medicine, Houston, Texas, USA
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4
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Daniali H, Flaten MA. Placebo Analgesia, Nocebo Hyperalgesia, and the Cardiovascular System: A Qualitative Systematic Review. Front Physiol 2020; 11:549807. [PMID: 33101048 PMCID: PMC7544987 DOI: 10.3389/fphys.2020.549807] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/17/2020] [Indexed: 12/31/2022] Open
Abstract
Background: Placebo/nocebo effects involve the autonomic nervous system, including cardiac activity, but studies have reported inconsistent findings on how cardiac activity is modulated following a placebo/nocebo effect. However, no systematic review has been conducted to provide a clear picture of cardiac placebo responses. Objective: The main goal of the present study is to review the effects of placebo analgesia and nocebo hyperalgesia on cardiac activity as measured by blood pressure, heart rate, and heart rate variability. Methods: Using several Boolean keyword combinations, the PubMed, EMBASE, PsycINFO, Cochrane Review Library, and ISI Web of Knowledge databases were searched until January 5, 2020, to find studies that analyzed blood pressure, heart rate, or heart rate variability indexes following a placebo analgesic/nocebo hyperalgesic effect. Results: Nineteen studies were found, with some reporting more than one index of cardiac activity; eight studies were on blood pressure, 14 studies on heart rate, and six on heart rate variability. No reliable association between placebo/nocebo effects and blood pressure or heart rate was found. However, placebo effects reduced, and nocebo effects increased low-frequency heart rate variability, and heart rate variability significantly predicted placebo effects in two studies. Conclusion: Placebo/nocebo effects can have reliable effects on heart rate variability, but not on heart rate and blood pressure.
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Affiliation(s)
| | - Magne Arve Flaten
- Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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5
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Benedetti F, Frisaldi E, Barbiani D, Camerone E, Shaibani A. Nocebo and the contribution of psychosocial factors to the generation of pain. J Neural Transm (Vienna) 2019; 127:687-696. [DOI: 10.1007/s00702-019-02104-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/12/2019] [Indexed: 12/17/2022]
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Beedie C, Benedetti F, Barbiani D, Camerone E, Lindheimer J, Roelands B. Incorporating methods and findings from neuroscience to better understand placebo and nocebo effects in sport. Eur J Sport Sci 2019; 20:313-325. [PMID: 31573836 PMCID: PMC10181912 DOI: 10.1080/17461391.2019.1675765] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Placebo and nocebo effects are a factor in sports performance. However, the majority of published studies in sport science are descriptive and speculative regarding mechanisms. It is therefore not unreasonable for the sceptic to argue that placebo and nocebo effects in sport are illusory, and might be better explained by variations in phenomena such as motivation. It is likely that, in sport at least, placebo and nocebo effects will remain in this empirical grey area until researchers provide stronger mechanistic evidence. Recent research in neuroscience has identified a number of consistent, discrete and interacting neurobiological and physiological pathways associated with placebo and nocebo effects, with many studies reporting data of potential interest to sport scientists, for example relating to pain, fatigue and motor control. Findings suggest that placebos and nocebos result in activity of the opioid, endocannabinoid and dopamine neurotransmitter systems, brain regions including the motor cortex and striatum, and measureable effects on the autonomic nervous system. Many studies have demonstrated that placebo and nocebo effects associated with a treatment, for example an inert treatment presented as an analgesic or stimulant, exhibit mechanisms similar or identical to the verum or true treatment. Such findings suggest the possibility of a wide range of distinct placebo and nocebo mechanisms that might influence sports performance. In the present paper, we present some of the findings from neuroscience. Focussing on fatigue as an outcome and caffeine as vehicle, we propose three approaches that researchers in sport might incorporate in their studies in order to better elucidate mechanisms of placebo/nocebo effects on performance.
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Affiliation(s)
- Christopher Beedie
- School of Psychology, University of Kent, Canterbury, UK
- CHX Performance, London, UK
| | - Fabrizio Benedetti
- Medicine and Physiology of Hypoxia, Plateau Rosà, Italy/Switzerland
- Neuroscience Dept, University of Turin Medical School, Turin, Italy
| | - Diletta Barbiani
- Neuroscience Dept, University of Turin Medical School, Turin, Italy
| | | | - Jacob Lindheimer
- Department of Veterans Affairs, William S. Middleton Veterans Memorial Hospital, Madison, WI, USA
- Department of Kinesiology, University of Wisconsin–Madison, Madison, WI, USA
| | - Bart Roelands
- Department of Human Physiology, Vije Universiteit Brussels, Belgium
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7
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Hurst P, Schipof-Godart L, Szabo A, Raglin J, Hettinga F, Roelands B, Lane A, Foad A, Coleman D, Beedie C. The Placebo and Nocebo effect on sports performance: A systematic review. Eur J Sport Sci 2019; 20:279-292. [DOI: 10.1080/17461391.2019.1655098] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Philip Hurst
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, UK
| | - Lieke Schipof-Godart
- Faculty of Health, Nutrition & Sports, The Hague University of Applied Sciences, Hague, Netherlands
| | - Attila Szabo
- Institute of Health Promotion and Sports Sciences, Eötvös Loránd University, Budapest, Hungary
| | - John Raglin
- School of Public Health, Indiana University, Bloomington, IN, USA
| | - Florentina Hettinga
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, UK
| | - Bart Roelands
- Department of Human Physiology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Andrew Lane
- Faculty of Education Health and Wellbeing, Institute of Sport, University of Wolverhampton, Walsall, UK
| | - Abby Foad
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, UK
| | - Damian Coleman
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, UK
| | - Chris Beedie
- School of Psychology, University of Kent, Canterbury, UK
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Detotto C, Isler S, Wehrle M, Vyssotski AL, Bettschart-Wolfensberger R, Gent TC. Nitrogen gas produces less behavioural and neurophysiological excitation than carbon dioxide in mice undergoing euthanasia. PLoS One 2019; 14:e0210818. [PMID: 30703117 PMCID: PMC6354991 DOI: 10.1371/journal.pone.0210818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 01/02/2019] [Indexed: 12/04/2022] Open
Abstract
Carbon dioxide (CO2) is one of the most commonly used gas euthanasia agents in mice, despite reports of aversion and nociception. Inert gases such as nitrogen (N2) may be a viable alternative to carbon dioxide. Here we compared behavioural and electrophysiological reactions to CO2 or N2 at either slow fill or rapid fill in C57Bl/6 mice undergoing gas euthanasia. We found that mice euthanised with CO2 increased locomotor activity compared to baseline, whereas mice exposed to N2 decreased locomotion. Furthermore, mice exposed to CO2 showed significantly more vertical jumps and freezing episodes than mice exposed to N2. We further found that CO2 exposure resulted in increased theta:delta of the EEG, a measure of excitation, whereas the N2 decreased theta:delta. Differences in responses were not oxygen-concentration dependent. Taken together, these results demonstrate that CO2 increases both behavioural and electrophysiological excitation as well as producing a fear response, whereas N2 reduces behavioural activity and central neurological depression and may be less aversive although still produces a fear response. Further studies are required to evaluate N2 as a suitable euthanasia agent for mice.
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Affiliation(s)
- Carlotta Detotto
- Section of Anaesthesiology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Sarah Isler
- Natur- und Tierpark Goldau, Goldau, Switzerland
| | | | | | | | - Thomas C. Gent
- Section of Anaesthesiology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- * E-mail:
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9
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Guidry A, Crutchfield K. Athletes with neurologic disease. HANDBOOK OF CLINICAL NEUROLOGY 2018; 158:445-462. [PMID: 30482372 DOI: 10.1016/b978-0-444-63954-7.00041-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neurologic disease does not discriminate, even among athletes. Common neurologic diseases among athletes include multiple sclerosis, seizures, headaches, and sleep disorders. Although concrete guidelines for sport participation among athletes with neurologic diseases do not exist, evidence-based and consensus statements can aid healthcare providers in determining whether and to what extent such athletes should participate in sports. Moreover, sport participation is important, since multiple studies indicate that exercise improves disease-specific symptoms, manifestations, and overall quality of life. Although some risk is involved for athletes with neurologic disease, risk is mitigated with proper supervision and neurologic oversight, disease-specific accommodations, and counseling of the athletic staff and the athletes. Neurologic oversight entails an initial comprehensive neurologic assessment by a neurologist followed by regular follow-up. Preparation for environmental conditions encountered by athletes with neurologic disease will further improve safety during their participation in sport. With sound recommendations, neurologic oversight, and proper supervision, most athletes with neurologic disease can participate in athletics. The health benefits that they will gain from participation in athletics outweigh the risks.
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Affiliation(s)
- Andrew Guidry
- Sports Medicine Institute, Sandra and Malcolm Berman Brain and Spine Institute at LifeBridge Health, Baltimore, MD, United States
| | - Kevin Crutchfield
- Sports Medicine Institute, Sandra and Malcolm Berman Brain and Spine Institute at LifeBridge Health, Baltimore, MD, United States.
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10
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Coleshill MJ, Sharpe L, Colloca L, Zachariae R, Colagiuri B. Placebo and Active Treatment Additivity in Placebo Analgesia: Research to Date and Future Directions. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 139:407-441. [PMID: 30146056 PMCID: PMC6179351 DOI: 10.1016/bs.irn.2018.07.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Placebo analgesia is a robust experimental and clinical phenomenon. While our understanding of the mechanisms of placebo analgesia has developed rapidly, some central questions remain unanswered. Among the important questions is how placebo analgesia interacts with active analgesic effects. It is an assumption underlying double-blind randomized placebo-controlled trials (RCTs) that the true effect of a treatment can be determined by examining the effect of the active treatment arm and subtracting the response in the placebo group ("the assumption of additivity"). However, despite the importance of this assumption for the interpretation of RCTs, it has rarely been formally examined. This article reviews the assumption of additivity in placebo analgesia by examining studies employing factorial designs manipulating both the receipt of an active analgesic and instructions about the treatment being delivered. In reviewing the literature, we identified seven studies that allowed a test of additivity. Of these, four found evidence against additivity, while the remaining three studies found results consistent with additivity. While the limited available data are somewhat mixed, the evidence suggests that at least under some conditions the assumption of additivity does not hold in placebo analgesia. The concordance between mechanisms of the active analgesic and placebo analgesia may influence whether additivity occurs or not. However, more research using factorial designs is needed to disentangle the relationship between placebo analgesia and the active effect of analgesic treatments.
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Affiliation(s)
- Matthew J Coleshill
- School of Psychology, University of Sydney, Sydney, NSW, Australia; St Vincent's Clinical School, St Vincent's Hospital, University of New South Wales, Sydney, NSW, Australia; Department of Clinical Pharmacology and Toxicology, St Vincent's Hospital, Sydney, NSW, Australia.
| | - Louise Sharpe
- School of Psychology, University of Sydney, Sydney, NSW, Australia
| | - Luana Colloca
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD, United States; School of Nursing, University of Maryland, Baltimore, MD, United States; School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Robert Zachariae
- Aarhus University Hospital and Department of Psychology and Behavioural Science, Aarhus University, Aarhus, Denmark
| | - Ben Colagiuri
- School of Psychology, University of Sydney, Sydney, NSW, Australia
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Simancas‐Racines D, Arevalo‐Rodriguez I, Osorio D, Franco JVA, Xu Y, Hidalgo R. Interventions for treating acute high altitude illness. Cochrane Database Syst Rev 2018; 6:CD009567. [PMID: 29959871 PMCID: PMC6513207 DOI: 10.1002/14651858.cd009567.pub2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Acute high altitude illness is defined as a group of cerebral and pulmonary syndromes that can occur during travel to high altitudes. It is more common above 2500 metres, but can be seen at lower elevations, especially in susceptible people. Acute high altitude illness includes a wide spectrum of syndromes defined under the terms 'acute mountain sickness' (AMS), 'high altitude cerebral oedema' and 'high altitude pulmonary oedema'. There are several interventions available to treat this condition, both pharmacological and non-pharmacological; however, there is a great uncertainty regarding their benefits and harms. OBJECTIVES To assess the clinical effectiveness, and safety of interventions (non-pharmacological and pharmacological), as monotherapy or in any combination, for treating acute high altitude illness. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science, CINAHL, Wanfang database and the World Health Organization International Clinical Trials Registry Platform for ongoing studies on 10 August 2017. We did not apply any language restriction. SELECTION CRITERIA We included randomized controlled trials evaluating the effects of pharmacological and non-pharmacological interventions for individuals suffering from acute high altitude illness: acute mountain sickness, high altitude pulmonary oedema or high altitude cerebral oedema. DATA COLLECTION AND ANALYSIS Two review authors independently assessed the eligibility of study reports, the risk of bias for each and performed the data extraction. We resolved disagreements through discussion with a third author. We assessed the quality of evidence with GRADE. MAIN RESULTS We included 13 studies enrolling a total of 468 participants. We identified two ongoing studies. All studies included adults, and two studies included both teenagers and adults. The 13 studies took place in high altitude areas, mostly in the European Alps. Twelve studies included participants with acute mountain sickness, and one study included participants with high altitude pulmonary oedema. Follow-up was usually less than one day. We downgraded the quality of the evidence in most cases due to risk of bias and imprecision. We report results for the main comparisons as follows.Non-pharmacological interventions (3 studies, 124 participants)All-cause mortality and complete relief of AMS symptoms were not reported in the three included trials. One study in 64 participants found that a simulated descent of 193 millibars versus 20 millibars may reduce the average of symptoms to 2.5 vs 3.1 units after 12 hours of treatment (clinical score ranged from 0 to 11 ‒ worse; reduction of 0.6 points on average with the intervention; low quality of evidence). In addition, no complications were found with use of hyperbaric chambers versus supplementary oxygen (one study; 29 participants; low-quality evidence).Pharmacological interventions (11 trials, 375 participants)All-cause mortality was not reported in the 11 included trials. One trial found a greater proportion of participants with complete relief of AMS symptoms after 12 and 16 hours when dexamethasone was administered in comparison with placebo (47.1% versus 0%, respectively; one study; 35 participants; low quality of evidence). Likewise, when acetazolamide was compared with placebo, the effects on symptom severity was uncertain (standardized mean difference (SMD) -1.15, 95% CI -2.56 to 0.27; 2 studies, 25 participants; low-quality evidence). One trial of dexamethasone in comparison with placebo in 35 participants found a reduction in symptom severity (difference on change in the AMS score: 3.7 units reported by authors; moderate quality of evidence). The effects from two additional trials comparing gabapentin with placebo and magnesium with placebo on symptom severity at the end of treatment were uncertain. For gabapentin versus placebo: mean visual analogue scale (VAS) score of 2.92 versus 4.75, respectively; 24 participants; low quality of evidence. For magnesium versus placebo: mean scores of 9 and 10.3 units, respectively; 25 participants; low quality of evidence). The trials did not find adverse events from either treatment (low quality of evidence). One trial comparing magnesium sulphate versus placebo found that flushing was a frequent event in the magnesium sulphate arm (percentage of flushing: 75% versus 7.7%, respectively; one study; 25 participants; low quality of evidence). AUTHORS' CONCLUSIONS There is limited available evidence to determine the effects of non-pharmacological and pharmacological interventions in treating acute high altitude illness. Low-quality evidence suggests that dexamethasone and acetazolamide might reduce AMS score compared to placebo. However, the clinical benefits and harms related to these potential interventions remain unclear. Overall, the evidence is of limited practical significance in the clinical field. High-quality research in this field is needed, since most trials were poorly conducted and reported.
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Affiliation(s)
- Daniel Simancas‐Racines
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
| | - Ingrid Arevalo‐Rodriguez
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
- Hospital Universitario Ramon y Cajal (IRYCIS)Clinical Biostatistics UnitMadridSpain
- CIBER Epidemiology and Public Health (CIBERESP)MadridSpain
| | - Dimelza Osorio
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
| | - Juan VA Franco
- Instituto Universitario Hospital ItalianoArgentine Cochrane CentrePotosí 4234Buenos AiresBuenos AiresArgentinaC1199ACL
| | - Yihan Xu
- Nanyang Technological UniversityWee Kim Wee School of Communication and InformationRoom 702, Building 5, #1277 Changning RoadSingapore CitySingapore637718
| | - Ricardo Hidalgo
- Universidad Tecnológica EquinoccialCochrane Ecuador. Centro de Investigación en Salud Pública y Epidemiología Clínica (CISPEC). Facultad de Ciencias de la Salud Eugenio EspejoQuitoEcuador
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Barbiani D, Camerone E, Benedetti F. What is the relative contribution of biological and psychosocial factors to the generation of hypoxia headache? CANADIAN JOURNAL OF PAIN-REVUE CANADIENNE DE LA DOULEUR 2018; 2:160-168. [PMID: 35005376 PMCID: PMC8730614 DOI: 10.1080/24740527.2018.1478224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Diletta Barbiani
- Neuroscience Department, University of Turin Medical School , Turin, Italy
- Plateau Rosà Laboratories , Plateau Rosà, Italy/Switzerland
| | - Eleonora Camerone
- Neuroscience Department, University of Turin Medical School , Turin, Italy
- Plateau Rosà Laboratories , Plateau Rosà, Italy/Switzerland
- Institute of Psychiatry, Psychology & Neuroscience, King’s College , London, UK
| | - Fabrizio Benedetti
- Neuroscience Department, University of Turin Medical School , Turin, Italy
- Plateau Rosà Laboratories , Plateau Rosà, Italy/Switzerland
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13
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Benedetti F, Barbiani D, Camerone E. Critical Life Functions: Can Placebo Replace Oxygen? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 138:201-218. [PMID: 29681326 DOI: 10.1016/bs.irn.2018.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A crucial question in placebo research is related to which conditions and physiological functions are affected by placebos. Here we present evidence that critical life functions, like ventilation, oxygenation, circulation, and perfusion, can be sensitive to placebo treatments in some circumstances. Indeed, we have investigated the role of placebo effects at an altitude of 3500m, where oxygen pressure is 64% compared to the sea level. In these extreme conditions, hypoxia triggers several compensatory responses, such as hyperventilation, increased cardiac output, and increased brain perfusion. A conditioned placebo procedure was found to mimic the effects of oxygen on these compensatory responses, and these effects are still present at altitudes as high as 4500 and 5500m, where oxygen pressure is only 57% and 50%, respectively, compared to the sea level. Thus, placebo effects also take place for those functions that are critical for life and whereby oxygen is the key element.
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Affiliation(s)
- Fabrizio Benedetti
- University of Turin Medical School, Turin, Italy; Plateau Rosà Laboratories, Plateau Rosà, Italy/Switzerland.
| | - Diletta Barbiani
- University of Turin Medical School, Turin, Italy; Plateau Rosà Laboratories, Plateau Rosà, Italy/Switzerland
| | - Eleonora Camerone
- Institute of Psychiatry, Psychology & Neuroscience, King's College, London, United Kingdom
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14
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Harvey SC, Beedie CJ. Studying placebo effects in model organisms will help us understand them in humans. Biol Lett 2017; 13:20170585. [PMID: 29187606 PMCID: PMC5719387 DOI: 10.1098/rsbl.2017.0585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/01/2017] [Indexed: 12/20/2022] Open
Abstract
The placebo effect is widely recognized but important questions remain, for example whether the capacity to respond to a placebo is an evolved, and potentially ubiquitous trait, or an unpredictable side effect of another evolved process. Understanding this will determine the degree to which the physiology underlying placebo effects might be manipulated or harnessed to optimize medical treatments. We argue that placebo effects are cases of phenotypic plasticity where once predictable cues are now unpredictable. Importantly, this explains why placebo-like effects are observed in less complex organisms such as worms and flies. Further, this indicates that such species present significant opportunities to test hypotheses that would be ethically or pragmatically impossible in humans. This paradigm also suggests that data informative of human placebo effects pre-exist in studies of model organisms.
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Affiliation(s)
- Simon C Harvey
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK
| | - Chris J Beedie
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK
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Shaibani A, Frisaldi E, Benedetti F. Placebo response in pain, fatigue, and performance: Possible implications for neuromuscular disorders. Muscle Nerve 2017; 56:358-367. [PMID: 28249354 DOI: 10.1002/mus.25635] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 02/15/2017] [Accepted: 02/26/2017] [Indexed: 12/17/2022]
Abstract
The placebo response in neuromuscular disorders is not well understood. The only available data regarding its underlying mechanisms are related to neuropathic pain. In this review, we describe the factors that contribute to improved outcomes in the placebo arm, with specific attention to pain and fatigue, as well as some of the most important psychobiological mechanisms that may explain such a response. This approach may also improve our insight into the symptomatology and therapeutic responses of other neuromuscular disorders. The fact that >90% of tested analgesics for neuropathic pain have failed in advanced phases of clinical trials should prompt a greater investment of effort and resources into understanding the mechanisms and impact of placebos in clinical research. Such an endeavor will help improve the design of clinical trials and will provide information that informs clinical neuromuscular practice. Muscle Nerve 56: 358-367, 2017.
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Affiliation(s)
- Aziz Shaibani
- Nerve & Muscle Center of Texas, Baylor College of Medicine, Houston, Texas, USA
| | - Elisa Frisaldi
- Neuroscience Department, University of Turin Medical School, Turin, Italy
| | - Fabrizio Benedetti
- Neuroscience Department, University of Turin Medical School, Turin, Italy.,Plateau Rosa Laboratories, Breuil-Cervinia, Italy, Zermatt, Turin, Switzerland
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16
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Bui SBD, Petersen T, Poulsen JN, Gazerani P. Simulated airplane headache: a proxy towards identification of underlying mechanisms. J Headache Pain 2017; 18:9. [PMID: 28130626 PMCID: PMC5272852 DOI: 10.1186/s10194-017-0724-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/17/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Airplane Headache (AH) occurs during flights and often appears as an intense, short lasting headache during take-off or landing. Reports are limited on pathological mechanisms underlying the occurrence of this headache. Proper diagnosis and treatments would benefit from identification of potential pathways involved in AH pathogenesis. This study aimed at providing a simulated airplane headache condition as a proxy towards identification of its underlying mechanisms. METHODS Fourteen participants including 7 volunteers suffering from AH and 7 healthy matched controls were recruited after meeting the diagnostic and safety criteria based on an approved study protocol. Simulation of AH was achieved by entering a pressure chamber with similar characteristics of an airplane flight. Selected potential biomarkers including salivary prostaglandin E2 (PGE2), cortisol, facial thermo-images, blood pressure, pulse, and saturation pulse oxygen (SPO) were defined and values were collected before, during and after flight simulation in the pressure chamber. Salivary samples were analyzed with ELISA techniques, while data analysis and statistical tests were handled with SPSS version 22.0. RESULTS All participants in the AH-group experienced a headache attack similar to AH experience during flight. The non-AH-group did not experience any headaches. Our data showed that the values for PGE2, cortisol and SPO were significantly different in the AH-group in comparison with the non-AH-group during the flight simulation in the pressure chamber. CONCLUSION The pressure chamber proved useful not only to provoke AH-like attack but also to study potential biomarkers for AH in this study. PGE2, and cortisol levels together with SPO presented dysregulation during the simulated AH-attack in affected individuals compared with healthy controls. Based on these findings we propose to use pressure chamber as a model to induce AH, and thus assess new potential biomarkers for AH in future studies.
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Affiliation(s)
- Sebastian Bao Dinh Bui
- SMI®, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Torben Petersen
- SMI®, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Jeppe Nørgaard Poulsen
- SMI®, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Parisa Gazerani
- SMI®, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
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Benedetti F, Dogue S. Different Placebos, Different Mechanisms, Different Outcomes: Lessons for Clinical Trials. PLoS One 2015; 10:e0140967. [PMID: 26536471 PMCID: PMC4633056 DOI: 10.1371/journal.pone.0140967] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/03/2015] [Indexed: 11/17/2022] Open
Abstract
Clinical trials use placebos with the assumption that they are inert, thus all placebos are considered to be equal. Here we show that this assumption is wrong and that different placebo procedures are associated to different therapeutic rituals which, in turn, trigger different mechanisms and produce different therapeutic outcomes. We studied high altitude, or hypobaric hypoxia, headache, in which two different placebos were administered. The first was placebo oxygen inhaled through a mask, whereas the second was placebo aspirin swallowed with a pill. Both placebos were given after a conditioning procedure, whereby either real oxygen or real aspirin was administered for three consecutive sessions to reduce headache pain. We found that after real oxygen conditioning, placebo oxygen induced pain relief along with a reduction in ventilation, blood alkalosis and salivary prostaglandin (PG)E2, yet without any increase in blood oxygen saturation (SO2). By contrast, after real aspirin conditioning, placebo aspirin induced pain relief through the inhibition of all the products of cyclooxygenase, that is, PGD2, PGE2, PGF2, PGI2, thromboxane (TX)A2, without affecting ventilation and blood alkalosis. Therefore, two different placebos, associated to two different therapeutic rituals, used two different pathways to reduce headache pain. The analgesic effect following placebo oxygen was superior to placebo aspirin. These findings show that different placebos may use different mechanisms to reduce high altitude headache, depending on the therapeutic ritual and the route of administration. In clinical trials, placebos and outcome measures should be selected very carefully in order not to incur in wrong interpretations.
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Affiliation(s)
- Fabrizio Benedetti
- University of Turin Medical School, Neuroscience Department, Turin, Italy.,Plateau Rosa Labs, Breuil-Cervinia, Italy, Zermatt, Switzerland
| | - Sara Dogue
- Plateau Rosa Labs, Breuil-Cervinia, Italy, Zermatt, Switzerland
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