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Dalecki M, Steinberg F, Beurskens R. Rapid Dual-Task Decrements After a Brief Period of Manual Tracking in Simulated Weightlessness by Water Submersion. HUMAN FACTORS 2023; 65:1001-1013. [PMID: 34861791 DOI: 10.1177/00187208211051804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
OBJECTIVE Investigating dual-task (DT) performance during simulated weightlessness by water submersion, using a manual tracking and a choice reaction task. In contrast to previous work, we focus on performance changes over time. BACKGROUND Previous research showed motor tracking and choice reaction impairments under DT and single-task (ST) conditions in shallow water submersion. Recent research analyzed performance as average across task time, neglecting potential time-related changes or fluctuations of task-performance. METHOD An unstable tracking and a choice reaction task was performed for one minute under ST and DT conditions in 5 m water submersion and on dry land in 43 participants. Tracking and choice reaction time performance for both tasks were analyzed in blocks of 10 seconds. RESULTS Tracking performance deteriorated underwater compared to dry land conditions during the second half while performing one minute in DT conditions. Choice reaction time increased underwater as well, but independent of task time and type. CONCLUSION Tracking error increased over time when performing unstable tracking and choice reaction together. Potentially, physiological and psychological alterations under shallow submersion further strain the human system during DT operations, exceeding available recourse capacities such that DT performance deteriorated over time. APPLICATION Humans operating in simulated weightlessness underwater should be aware of substantial performance declines that can occur within a short amount of time during DT situations that include continuous tracking.
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Affiliation(s)
- Marc Dalecki
- School of Kinesiology, Louisiana State University, Baton Rouge, LA, USA
| | - Fabian Steinberg
- School of Kinesiology, Louisiana State University, Baton Rouge, LA, USA
| | - Rainer Beurskens
- Fachhochschule des Mittelstandes, University of Applied Sciences, Bielefeld, Germany
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2
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Muth T, Schipke JD, Brebeck AK, Dreyer S. Assessing Critical Flicker Fusion Frequency: Which Confounders? A Narrative Review. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59040800. [PMID: 37109758 PMCID: PMC10141404 DOI: 10.3390/medicina59040800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/13/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023]
Abstract
The critical flicker fusion frequency (cFFF) refers to the frequency at which a regularly recurring change of light stimuli is perceived as steady. The cFFF threshold is often assessed in clinics to evaluate the temporal characteristics of the visual system, making it a common test for eye diseases. Additionally, it serves as a helpful diagnostic tool for various neurological and internal diseases. In the field of diving/hyperbaric medicine, cFFF has been utilized to determine alertness and cognitive functions. Changes in the cFFF threshold have been linked to the influence of increased respiratory gas partial pressures, although there exist inconsistent results regarding this effect. Moreover, the use of flicker devices has produced mixed outcomes in previous studies. This narrative review aims to explore confounding factors that may affect the accuracy of cFFF threshold measurements, particularly in open-field studies. We identify five broad categories of such factors, including (1) participant characteristics, (2) optical factors, (3) smoking/drug use, (4) environmental aspects, and (5) breathing gases and partial pressures. We also discuss the application of cFFF measurements in the field of diving and hyperbaric medicine. In addition, we provide recommendations for interpreting changes in the cFFF threshold and how they are reported in research studies.
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Affiliation(s)
- Thomas Muth
- Institute of Occupational, Social, Environmental Medicine, Faculty of Medicine, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Jochen D Schipke
- Research Group Experimental Surgery, University Hospital Düsseldorf, 40225 Düsseldorf, Germany
| | | | - Sven Dreyer
- Hyperbaric Oxygen Therapy, University Hospital Düsseldorf, 40225 Düsseldorf, Germany
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3
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Vrijdag XCE, van Waart H, Sames C, Mitchell SJ, Sleigh JW. Does hyperbaric oxygen cause narcosis or hyperexcitability? A quantitative EEG analysis. Physiol Rep 2022; 10:e15386. [PMID: 35859332 PMCID: PMC9300958 DOI: 10.14814/phy2.15386] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 11/24/2022] Open
Abstract
Divers breathe higher partial pressures of oxygen at depth than at the surface. The literature and diving community are divided on whether or not oxygen is narcotic. Conversely, hyperbaric oxygen may induce dose‐dependent cerebral hyperexcitability. This study evaluated whether hyperbaric oxygen causes similar narcotic effects to nitrogen, and investigated oxygen's hyperexcitability effect. Twelve human participants breathed “normobaric” air and 100% oxygen, and “hyperbaric” 100% oxygen at 142 and 284 kPa, while psychometric performance, electroencephalography (EEG), and task load perception were measured. EEG was analyzed with functional connectivity and temporal complexity algorithms. The spatial functional connectivity, estimated using mutual information, was summarized with the global efficiency network measure. Temporal complexity was calculated with a “default‐mode‐network (DMN) complexity” algorithm. Hyperbaric oxygen‐breathing caused no change in EEG global efficiency or in the psychometric test. However, oxygen caused a significant reduction of DMN complexity and a reduction in task load perception. Hyperbaric oxygen did not cause the same changes in EEG global efficiency seen with hyperbaric air, which likely related to a narcotic effect of nitrogen. Hyperbaric oxygen seemed to disturb the time evolution of EEG patterns that could be taken as evidence of early oxygen‐induced cortical hyperexcitability. These findings suggest that hyperbaric oxygen is not narcotic and will help inform divers' decisions on suitable gas mixtures.
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Affiliation(s)
- Xavier C E Vrijdag
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Hanna van Waart
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Chris Sames
- Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, New Zealand
| | - Simon J Mitchell
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, New Zealand.,Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
| | - Jamie W Sleigh
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
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4
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Vrijdag XCE, van Waart H, Pullon RM, Sames C, Mitchell SJ, Sleigh JW. EEG functional connectivity is sensitive for nitrogen narcosis at 608 kPa. Sci Rep 2022; 12:4880. [PMID: 35318392 PMCID: PMC8940999 DOI: 10.1038/s41598-022-08869-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/14/2022] [Indexed: 12/21/2022] Open
Abstract
Divers commonly breathe air, containing nitrogen. Nitrogen under hyperbaric conditions is a narcotic gas. In dives beyond a notional threshold of 30 m depth (405 kPa) this can cause cognitive impairment, culminating in accidents due to poor decision making. Helium is known to have no narcotic effect. This study explored potential approaches to developing an electroencephalogram (EEG) functional connectivity metric to measure narcosis produced by nitrogen at hyperbaric pressures. Twelve human participants (five female) breathed air and heliox (in random order) at 284 and 608 kPa while recording 32-channel EEG and psychometric function. The degree of spatial functional connectivity, estimated using mutual information, was summarized with global efficiency. Air-breathing at 608 kPa (experienced as mild narcosis) caused a 35% increase in global efficiency compared to surface air-breathing (mean increase = 0.17, 95% CI [0.09–0.25], p = 0.001). Air-breathing at 284 kPa trended in a similar direction. Functional connectivity was modestly associated with psychometric impairment (mixed-effects model r2 = 0.60, receiver-operating-characteristic area, 0.67 [0.51–0.84], p = 0.02). Heliox breathing did not cause a significant change in functional connectivity. In conclusion, functional connectivity increased during hyperbaric air-breathing in a dose-dependent manner, but not while heliox-breathing. This suggests sensitivity to nitrogen narcosis specifically.
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Affiliation(s)
- Xavier C E Vrijdag
- Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland, 1142, New Zealand.
| | - Hanna van Waart
- Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland, 1142, New Zealand
| | - Rebecca M Pullon
- Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland, 1142, New Zealand.,Department of Anaesthesia, Waikato Hospital, Hamilton, 3240, New Zealand
| | - Chris Sames
- Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, 0610, New Zealand
| | - Simon J Mitchell
- Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland, 1142, New Zealand.,Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, 0610, New Zealand.,Department of Anaesthesia, Auckland City Hospital, Auckland, 1023, New Zealand
| | - Jamie W Sleigh
- Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland, 1142, New Zealand.,Department of Anaesthesia, Waikato Hospital, Hamilton, 3240, New Zealand
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5
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Oxygen-enriched air reduces breathing gas consumption over air. Curr Res Physiol 2022; 5:79-82. [DOI: 10.1016/j.crphys.2022.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/14/2022] [Accepted: 01/27/2022] [Indexed: 11/22/2022] Open
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6
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Mankowska ND, Marcinkowska AB, Waskow M, Sharma RI, Kot J, Winklewski PJ. Critical Flicker Fusion Frequency: A Narrative Review. MEDICINA (KAUNAS, LITHUANIA) 2021; 57:1096. [PMID: 34684133 PMCID: PMC8537539 DOI: 10.3390/medicina57101096] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022]
Abstract
This review presents the current knowledge of the usage of critical flicker fusion frequency (CFF) in human and animal model studies. CFF has a wide application in different fields, especially as an indicator of cortical arousal and visual processing. In medicine, CFF may be helpful for diagnostic purposes, for example in epilepsy or minimal hepatic encephalopathy. Given the environmental studies and a limited number of other methods, it is applicable in diving and hyperbaric medicine. Current research also shows the relationship between CFF and other electrophysiological methods, such as electroencephalography. The human eye can detect flicker at 50-90 Hz but reports are showing the possibility to distinguish between steady and modulated light up to 500 Hz. Future research with the use of CFF is needed to better understand its utility and application.
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Affiliation(s)
- Natalia D. Mankowska
- Applied Cognitive Neuroscience Lab, Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
| | - Anna B. Marcinkowska
- Applied Cognitive Neuroscience Lab, Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- 2nd Department of Radiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Institute of Health Sciences, Pomeranian University in Slupsk, 76-200 Slupsk, Poland;
| | - Monika Waskow
- Institute of Health Sciences, Pomeranian University in Slupsk, 76-200 Slupsk, Poland;
| | - Rita I. Sharma
- Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Department of Anaesthesiology and Intensive Care, Medical University of Gdansk, 80-210 Gdansk, Poland
| | - Jacek Kot
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine in Gdynia, Medical University of Gdansk, 80-210 Gdansk, Poland;
| | - Pawel J. Winklewski
- 2nd Department of Radiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
- Institute of Health Sciences, Pomeranian University in Slupsk, 76-200 Slupsk, Poland;
- Department of Human Physiology, Medical University of Gdansk, 80-210 Gdansk, Poland;
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7
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Möller F, Jacobi E, Hoffmann U, Muth T, Schipke JD. Oxygen-enriched Air Decreases Ventilation during High-intensity Fin-swimming Underwater. Int J Sports Med 2021; 43:230-236. [PMID: 34399427 PMCID: PMC8885326 DOI: 10.1055/a-1554-5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Oxygen-enriched air is commonly used in the sport of SCUBA-diving and might affect ventilation and heart rate, but little work exists for applied diving settings. We hypothesized that ventilation is decreased especially during strenuous underwater fin-swimming when using oxygen-enriched air as breathing gas. Ten physically-fit divers (age: 25±4; 5 females; 67±113 open-water dives) performed incremental underwater fin-swimming until exhaustion at 4 m water depth with either normal air or oxygen-enriched air (40% O
2
) in a double-blind, randomized within-subject design. Heart rate and ventilation were measured throughout the dive and maximum whole blood lactate samples were determined post-exercise. ANOVAs showed a significant effect for the factor breathing gas (F(1, 9)=7.52; P=0.023; η
2p
=0.455), with a lower ventilation for oxygen-enriched air during fin-swimming velocities of 0.6 m·s
−1
(P=0.032) and 0.8 m·s
−1
(P=0.037). Heart rate, lactate, and time to exhaustion showed no significant differences. These findings indicate decreased ventilation by an elevated oxygen fraction in the breathing gas when fin-swimming in shallow-water submersion with high velocity (>0.5 m·s
−1
). Applications are within involuntary underwater exercise or rescue scenarios for all dives with limited gas supply.
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Affiliation(s)
- Fabian Möller
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Elena Jacobi
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Uwe Hoffmann
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Thomas Muth
- Occupational, Social, Environmental Medicine, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Jochen D Schipke
- Research Group Experimenal Surgery, University Hospital Düsseldorf, Dusseldorf, Germany
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8
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Karakaya H, Aksu S, Egi SM, Aydin S, Uslu A. Effects of Hyperbaric Nitrogen Narcosis on Cognitive Performance in Recreational air SCUBA Divers: An Auditory Event-related Brain Potentials Study. Ann Work Expo Health 2021; 65:505-515. [PMID: 33942846 DOI: 10.1093/annweh/wxaa132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/21/2020] [Accepted: 12/01/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The narcotic effect of hyperbaric nitrogen is most pronounced in air-breathing divers because it impairs diver's cognitive and behavioral performance, and limits the depth of dive profiles. We aimed to investigate the cognitive effects of simulated (500 kPa) air environments in recreational SCUBA divers, revealed by auditory event-related potentials (AERPs). METHODS A total of 18 healthy volunteer recreational air SCUBA divers participated in the study. AERPs were recorded in pre-dive, deep-dive, and post-dive sessions. RESULTS False-positive score variables were found with significantly higher differences and longer reaction times of hits during deep-dive and post-dive than pre-dive sessions. Also, P3 amplitudes were significantly reduced and peak latencies were prolonged during both deep-dive and post-dive compared with pre-dive sessions. CONCLUSION We observed that nitrogen narcosis at 500 kPa pressure in the dry hyperbaric chamber has a mild-to-moderate negative effect on the cognitive performance of recreational air SCUBA divers, which threatened the safety of diving. Although relatively decreased, this effect also continued in the post-dive sessions. These negative effects are especially important for divers engaged in open-sea diving. Our results show crucial implications for the kinds of control measures that can help to prevent nitrogen narcosis and diving accidents at depths up to 40 msw.
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Affiliation(s)
- Huseyin Karakaya
- Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
| | - Serkan Aksu
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
| | - Salih Murat Egi
- Department of Computer Engineering, Faculty of Engineering and Technology, Galatasaray University, Ortakoy, Istanbul, Turkey
| | - Salih Aydin
- Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
| | - Atilla Uslu
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
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9
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Berenji Ardestani S, Balestra C, Bouzinova EV, Loennechen Ø, Pedersen M. Evaluation of Divers' Neuropsychometric Effectiveness and High-Pressure Neurological Syndrome via Computerized Test Battery Package and Questionnaires in Operational Setting. Front Physiol 2019; 10:1386. [PMID: 31787904 PMCID: PMC6856207 DOI: 10.3389/fphys.2019.01386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/22/2019] [Indexed: 12/19/2022] Open
Abstract
Introduction: When divers are compressed to water depths deeper than 150 meter sea water (msw), symptoms of high-pressure neurological syndrome (HPNS) might appear due to rapid increase in pressure on the central nervous system during compression. The aim of this study was to first operate a new computerized tool, designed to monitor divers’ wellbeing and cognitive function, and to record the results. The second aim was to evaluate the feasibility and validity of the Physiopad software and HPNS questionnaires as a new tool for monitoring divers wellbeing in an operational setting, including sensible visualization and presentation of results. Methods: The Physiopad was operated onboard Deep Arctic (TechnipFMC Diving Support Vessel). The diving work was performed between 180 and 207 msw. The data from 46 divers were collected from the HPNS questionnaires, Hand dynamometry test, Critical Flicker Fusion Frequency test (CFFF), Adaptive Visual Analog Scale (AVAS), Simple Math Process (MathProc test), Perceptual Vigilance Task (PVT), and Time Estimation Task (time-wall). Result: Diver’s subjective evaluation revealed different symptoms, possibly also HPNS related, which lasted from 1 to 5 days in storage, with the common duration being 1 day. The results from Physiopad battery testing showed no signs of significant neurological alteration. Conclusion: The present study showed that there was no association between subjective measurements of HPNS and neuropsychometric test results. We also confirmed the feasibility of using the computerized test battery to monitor saturation divers at work. The HPNS battery and Physiopad software could be an important tool for monitoring diver’s health in the future. This tool was not used during the Bahr Essalam project to operationally evaluate any HPNS effect on divers as data analysis was performed post-project.
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Affiliation(s)
- Simin Berenji Ardestani
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Costantino Balestra
- Divers Alert Network Europe - Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | | | | | - Michael Pedersen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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10
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Martin K, McLeod E, Périard J, Rattray B, Keegan R, Pyne DB. The Impact of Environmental Stress on Cognitive Performance: A Systematic Review. HUMAN FACTORS 2019; 61:1205-1246. [PMID: 31002273 DOI: 10.1177/0018720819839817] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
OBJECTIVE In this review, we detail the impact of environmental stress on cognitive and military task performance and highlight any individual characteristics or interventions which may mitigate any negative effect. BACKGROUND Military personnel are often deployed in regions markedly different from their own, experiencing hot days, cold nights, and trips both above and below sea level. In spite of these stressors, high-level cognitive and operational performance must be maintained. METHOD A systematic review of the electronic databases Medline (PubMed), EMBASE (Scopus), PsycINFO, and Web of Science was conducted from inception up to September 2018. Eligibility criteria included a healthy human cohort, an outcome of cognition or military task performance and assessment of an environmental condition. RESULTS The search returned 113,850 records, of which 124 were included in the systematic review. Thirty-one studies examined the impact of heat stress on cognition; 20 of cold stress; 59 of altitude exposure; and 18 of being below sea level. CONCLUSION The severity and duration of exposure to the environmental stressor affects the degree to which cognitive performance can be impaired, as does the complexity of the cognitive task and the skill or familiarity of the individual performing the task. APPLICATION Strategies to improve cognitive performance in extreme environmental conditions should focus on reducing the magnitude of the physiological and perceptual disturbance caused by the stressor. Strategies may include acclimatization and habituation, being well skilled on the task, and reducing sensations of thermal stress with approaches such as head and neck cooling.
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Affiliation(s)
- Kristy Martin
- University of Canberra, Australian Capital Territory, Australia
| | - Emily McLeod
- University of Canberra, Australian Capital Territory, Australia
| | - Julien Périard
- University of Canberra, Australian Capital Territory, Australia
| | - Ben Rattray
- University of Canberra, Australian Capital Territory, Australia
| | - Richard Keegan
- University of Canberra, Australian Capital Territory, Australia
| | - David B Pyne
- University of Canberra, Australian Capital Territory, Australia
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11
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De Bels D, Pierrakos C, Bruneteau A, Reul F, Crevecoeur Q, Marrone N, Vissenaeken D, Borgers G, Balestra C, Honoré PM, Theunissen S. Variation of Cognitive Function During a Short Stay at Hypobaric Hypoxia Chamber (Altitude: 3842 M). Front Physiol 2019; 10:806. [PMID: 31316394 PMCID: PMC6611417 DOI: 10.3389/fphys.2019.00806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
Objective To observe the effects of a fast-acute ascent to high altitude on brain cognitive function and transcranial doppler parameters in order to understand the physiological countermeasures of hypoxia. Methods 17 high-altitude-naïve male subjects (mean age was 26.3 ± 8.1 years) participated in the study. We measured Critical Flicker Fusion Frequency (CFFF), blood oxygen saturation, Psychology Experiment Building (PEBL) including three tests (Modified Math Processing Task, Perceptual Vigilance Task, and Time Estimation Task), as well as Cerebral Blood Flow index (CBFi), mean cerebral artery Systolic and diastolic velocities, Cerebral Pulsatility index (CPi), and heart Rate. All were measured at sea level, at least 1 h after arrival at the hypobaric hypoxia equivalent of 3842 m and 1 h after return to sea level. Results Under acute exposure to hypobaric hypoxic conditions, significant decrease in CFFF [42.1 ± 1 vs. 43.5 ± 1.7 Hz at sea level (asl), p < 0.01], CBFi (611 ± 51 vs. 665 ± 71 asl, p < 0.01) and blood oxygen saturation (83 ± 4% vs. 98 ± 1% asl, p < 0.001) as compared to pre-ascent values were observed. Physiological countermeasures to hypoxia could be involved as there was no significant change in neuropsychometric tests, Systolic and Diastolic velocities and CPi. A significant increase in Heart Rate (81 ± 15 bpm vs. 66 ± 15 bpm asl, p < 0.001) was observed. All parameters returned to their basal values 1 h after regaining sea level. Conclusion Hypoxia results in a decrease in CFFF, CBFi and oxygen saturation and in an increase in heart rate. As it decreased, Cerebral Blood Flow index does not seem to be the physiological measurement of choice to hypoxia explaining the maintenance of cognitive performance after acute exposure to hypobaric hypoxia and requires further investigation. Cerebral oxygen delivery and extraction could be one of the underlying mechanisms.
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Affiliation(s)
- D De Bels
- Department of Intensive Care Medicine, Brugmann University Hospital, Brussels, Belgium.,Unit of Oxygen Study, Translational Research Laboratory, Université Libre de Bruxelles, Brussels, Belgium.,Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - C Pierrakos
- Department of Intensive Care Medicine, Brugmann University Hospital, Brussels, Belgium.,Unit of Oxygen Study, Translational Research Laboratory, Université Libre de Bruxelles, Brussels, Belgium
| | - A Bruneteau
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - F Reul
- Faculty of Medicine, Université catholique de Louvain, Brussels, Belgium
| | - Q Crevecoeur
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - N Marrone
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - D Vissenaeken
- Hypobaric Chamber, Queen Astrid Military Hospital, Brussels, Belgium
| | - G Borgers
- Hypobaric Chamber, Queen Astrid Military Hospital, Brussels, Belgium
| | - C Balestra
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - P M Honoré
- Department of Intensive Care Medicine, Brugmann University Hospital, Brussels, Belgium
| | - S Theunissen
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
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12
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Lafère P, Hemelryck W, Germonpré P, Matity L, Guerrero F, Balestra C. Early detection of diving-related cognitive impairment of different nitrogen-oxygen gas mixtures using critical flicker fusion frequency. Diving Hyperb Med 2019; 49:119-126. [PMID: 31177518 DOI: 10.28920/dhm49.2.119-126] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/08/2019] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Cognitive impairment related to inert gas narcosis (IGN) is a threat to diving safety and operations at depth that might be reduced by using enriched air nitrox (EANx) mixtures. Using critical flicker fusion frequency (CFFF), a possible early detection of cognitive abilities/cerebral arousal impairment when breathing different oxygen (O2) fractions was investigated. METHODS Eight male volunteers performed, in random order, two dry chamber dives breathing either air or EANx40 (40% O₂-60% nitrogen) for 20 minutes (min) at 0.4 MPa. Cognition and arousal were assessed before the dive; upon arrival at 0.4 MPa; after 15 min exposure at 0.4 MPa; on surfacing and 30 min post-dive using behavioural computer-based testing psychology experiment building language (PEBL) and by CFFF while continuously recording brain oxygenation with near-infrared spectroscopy. RESULTS In both breathing conditions, CFFF and PEBL demonstrated a significant inverse correlation (Pearson r of -0.90, P < 0.0001), improved cognitive abilities/cerebral arousal occurred upon arrival at 0.4 MPa followed by a progressive deterioration. Initial brain activation was associated with a significant increase in oxyhaemoglobin (HbO2) and a simultaneous decrease of deoxyhaemoglobin (HHb). The magnitude of the changes was significantly greater under EANx (P = 0.038). CONCLUSIONS Since changes were not related to haemodynamic variables, HbO₂ and HHb values indicate a significant, O₂-dependent activation in the prefrontal cortex. Owing to the correlation with some tests from the PEBL, CFFF could be a convenient measure of cognitive performance/ability in extreme environments, likely under the direct influence of oxygen partial pressure, a potent modulator of IGN symptoms.
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Affiliation(s)
- Pierre Lafère
- DAN Europe Research Division, Roseto, Italy.,Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, Brest, France.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Corresponding author: Pierre Lafère, Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu - CS 93837, 29238 Brest Cedex 3, France,
| | - Walter Hemelryck
- DAN Europe Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - Peter Germonpré
- DAN Europe Research Division, Roseto, Italy.,Centre for Hyperbaric Oxygen Therapy, Military Hospital 'Queen Astrid', Brussels
| | | | - François Guerrero
- DAN Europe Research Division, Roseto, Italy.,Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, Brest, France
| | - Costantino Balestra
- DAN Europe Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel (V.U.B.), Brussels.,Anatomical Research Training and Education (ARTE), Vrije Universiteit Brussel (V.U.B.).,Motor Sciences, Université Libre De Bruxelles (U.L.B.), Brussels
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13
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Rocco M, Pelaia P, Di Benedetto P, Conte G, Maggi L, Fiorelli S, Mercieri M, Balestra C, De Blasi RA. Inert gas narcosis in scuba diving, different gases different reactions. Eur J Appl Physiol 2018; 119:247-255. [PMID: 30350155 DOI: 10.1007/s00421-018-4020-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/13/2018] [Indexed: 12/25/2022]
Abstract
PURPOSE Underwater divers face several potential neurological hazards when breathing compressed gas mixtures including nitrogen narcosis which can impact diver's safety. Various human studies have clearly demonstrated brain impairment due to nitrogen narcosis in divers at 4 ATA using critical flicker fusion frequency (CFFF) as a cortical performance indicator. However, recently some authors have proposed a probable adaptive phenomenon during repetitive exposure to high nitrogen pressure in rats, where they found a reversal effect on dopamine release. METHODS Sixty experienced divers breathing Air, Trimix or Heliox, were studied during an open water dive to a depth of 6 ATA with a square profile testing CFFF measurement before (T0), during the dive upon arriving at the bottom (6 ATA) (T1), 20 min of bottom time (T2), and at 5 m (1.5 ATA) (T3). RESULTS CFFF results showed a slight increase in alertness and arousal during the deep dive regardless of the gas mixture breathed. The percent change in CFFF values at T1 and T2 differed among the three groups being lower in the air group than in the other groups. All CFFF values returned to basal values 5 min before the final ascent at 5 m (T3), but the Trimix measurements were still slightly better than those at T0. CONCLUSIONS Our results highlight that nitrogen and oxygen alone and in combination can produce neuronal excitability or depression in a dose-related response.
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Affiliation(s)
- Monica Rocco
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy.
| | - P Pelaia
- Department of Biomedical Sciences and Public Health, Anesthesia and Intensive Care, Università Politecnica delle Marche Torrette, Ancona, Italy
| | - P Di Benedetto
- Azienda Ospedaliero, Universitaria Sant'Andrea, Rome, Italy
| | - G Conte
- Department of Informatics Engineering, University Politecnica delle Marche, Ancona, Italy
| | - L Maggi
- Anesthesia and Intensive Care, Università Campus Biomedico, Rome, Italy
| | - S Fiorelli
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy
| | - M Mercieri
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy
| | - C Balestra
- Environmental, Occupational and Ageing (Integrative) Physiology Lab, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - R A De Blasi
- Department of Surgical and Medical Science and Translational Medicine, Anesthesia and Intensive Care, Sapienza University, Rome, Italy
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14
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Balestra C, Machado ML, Theunissen S, Balestra A, Cialoni D, Clot C, Besnard S, Kammacher L, Delzenne J, Germonpré P, Lafère P. Critical Flicker Fusion Frequency: A Marker of Cerebral Arousal During Modified Gravitational Conditions Related to Parabolic Flights. Front Physiol 2018; 9:1403. [PMID: 30333762 PMCID: PMC6175980 DOI: 10.3389/fphys.2018.01403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/14/2018] [Indexed: 12/27/2022] Open
Abstract
In situ evaluation of human brain performance and arousal remains challenging during operational circumstances, hence the need for a rapid, reliable and reproducible tool. Here we hypothesized that the Critical flicker fusion frequency (CFFF) reflecting/requiring visual integration, visuo-motor skills and decision-taking process might be a powerful, fast and simple tool in modified gravity environments. Therefore 11 male healthy volunteers were assessed for higher cognitive functions with CFFF during parabolic flights. They were assessed at different time points: upon arrival to the base, 30 min after subcutaneous scopolamine administration, before parabolas, during hypergravity and microgravity at break time (between the 16th and the 17th parabola), on the return flight and on the ground after landing. First, a stable, and consistent measurement of CFFF could be obtained within 12 s. Second, under modified gravitational conditions, the perceptual ability of participants is significantly modified. Compared to the baseline, evolution is characterized by a significant increase of CFFF when in microgravity (0g: 106.9 ± 5.5%), and a significant decrease of CFFF while in hypergravity (2g: 94.5 ± 3.8%). Other time-points were not statistically different from the baseline value. Although the underlying mechanism is still debated, we suggest that the CFFF test is a global marker of cerebral arousal as the result of visuo-motor and decision taking testing based on a simple visual stimulus with an uncomplicated set up that could be used under various environmental conditions. The authors express an opinion that it would be advisable to introduce CFFF measurement during spaceflights as it allows individual longitudinal assessment of individual ability even under conditions of incomplete physiological compensation, as shown here during parabolic flights.
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Affiliation(s)
- Costantino Balestra
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Divers Alert Network (DAN) Europe Research Division, Brussels, Belgium
| | | | - Sigrid Theunissen
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - Ambre Balestra
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - Danilo Cialoni
- Divers Alert Network (DAN) Europe Research Division, Brussels, Belgium
| | - Christian Clot
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,UNICAEN, INSERM, COMETE, Normandie Université, Caen, France
| | | | | | - Julie Delzenne
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Belgian Road Safety Institute (BRSI), Brussels, Belgium
| | - Peter Germonpré
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Divers Alert Network (DAN) Europe Research Division, Brussels, Belgium.,Centre for Hyperbaric Oxygen Therapy, Military Hospital "Queen Astrid", Brussels, Belgium
| | - Pierre Lafère
- Environmental, Occupational and Ageing "Integrative Physiology" Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Divers Alert Network (DAN) Europe Research Division, Brussels, Belgium.,Laboratoire ORPHY, EA4324 UFR Sciences et Techniques, Université de Bretagne Occidentale, Brest, France
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15
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Steinberg F, Doppelmayr M. Executive Functions of Divers Are Selectively Impaired at 20-Meter Water Depth. Front Psychol 2017; 8:1000. [PMID: 28676772 PMCID: PMC5476772 DOI: 10.3389/fpsyg.2017.01000] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/31/2017] [Indexed: 11/13/2022] Open
Abstract
Moving and acting underwater within recreational or occupational activities require intact executive functions, since they subserve higher cognitive functions such as successful self-regulation, coping with novel situations, and decision making; all of which could be influenced by nitrogen narcosis due to elevated partial pressure under water. However, specific executive functions that could provide a differentiated view on humans' cognitive performance ability have not yet been systematically analyzed in full-water immersion, which is a research gap addressed within this approach to contribute to a better understanding of nitrogen narcosis. In this study, 20 young, healthy, and certified recreational divers participated and performed three different executive-function tests: the Stroop test (Inhibition), the Number/Letter test (Task switching), the 2-back test (Updating/Working memory), and a simple reaction time test (Psychomotor performance). These tests were performed once on land, at 5-meter (m) water depth, and at 20-meter (m) water depth of an indoor diving facility in standardized test conditions (26°C in all water depths). A water-proofed and fully operational tablet computer was used to present visual stimuli and to register reaction times. Performance of the simple reaction time test was not different between underwater and land testing, suggesting that reaction times were not biased by the utilization of the tablet in water immersion. Executive functions were not affected by the shallow water immersion of 5-m water depth. However, performance scores in 20-m water depth revealed a decreased performance in the incongruent test condition (i.e., an index of inhibitory control ability) of the Stroop test, while all other tests were unaffected. Even though only one out of the three tested cognitive domains was affected, the impairment of inhibitory control ability even in relatively shallow water of 20-m is a critical component that should be considered for diver's safety, since inhibition is required in self-control requiring situations where impulsive and automatic behavior must be inhibited. Our interpretation of these selective impairments is based on a discussion suggesting that different neural networks within the central nervous system, which process specific executive functions, are affected differently by nitrogen narcosis.
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Affiliation(s)
- Fabian Steinberg
- Department of Sport Psychology, Institute of Sport Science, Johannes Gutenberg University MainzMainz, Germany
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