scholarly journals Assessment of Alertness and Cognitive Performance of Closed Circuit Rebreather Divers With the Critical Flicker Fusion Frequency Test in Arctic Diving Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Wilhelme W. Piispanen ◽  
Richard V. Lundell ◽  
Laura J. Tuominen ◽  
Anne K. Räisänen-Sokolowski

Introduction: Cold water imposes many risks to the diver. These risks include decompression illness, physical and cognitive impairment, and hypothermia. Cognitive impairment can be estimated using a critical flicker fusion frequency (CFFF) test, but this method has only been used in a few studies conducted in an open water environment. We studied the effect of the cold and a helium-containing mixed breathing gas on the cognition of closed circuit rebreather (CCR) divers.Materials and Methods: Twenty-three divers performed an identical dive with controlled trimix gas with a CCR device in an ice-covered quarry. They assessed their thermal comfort at four time points during the dive. In addition, their skin temperature was measured at 5-min intervals throughout the dive. The divers performed the CFFF test before the dive, at target depth, and after the dive.Results: A statistically significant increase of 111.7% in CFFF values was recorded during the dive compared to the pre-dive values (p < 0.0001). The values returned to the baseline after surfacing. There was a significant drop in the divers’ skin temperature of 0.48°C every 10 min during the dive (p < 0.001). The divers’ subjectively assessed thermal comfort also decreased during the dive (p = 0.01).Conclusion: Our findings showed that neither extreme cold water nor helium-containing mixed breathing gas had any influence on the general CFFF profile described in the previous studies from warmer water and where divers used other breathing gases. We hypothesize that cold-water diving and helium-containing breathing gases do not in these diving conditions cause clinically relevant cerebral impairment. Therefore, we conclude that CCR diving in these conditions is safe from the perspective of alertness and cognitive performance.

Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1096
Author(s):  
Natalia D. Mankowska ◽  
Anna B. Marcinkowska ◽  
Monika Waskow ◽  
Rita I. Sharma ◽  
Jacek Kot ◽  
...  

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.


2019 ◽  
Vol 98 (12) ◽  
pp. 1402-1407
Author(s):  
Vladislav R. Kuchma ◽  
S. V. Sankov ◽  
N. K. Barsukova

Introduction. Currently, in connection with the large-scale introduction of the electronic educational resource in the educational process, it is especially relevant to search for optimal characteristics of presenting information on screens, taking into account the specifics of the electronic devices and age-related physiological features of the users’ visual system. The aim of the study was a physiological hygienic assessment of the impact of the font design of e-texts, presented on a laptop, on the psychophysiological state of students in grades 10-11. Material and methods. Psychophysiological testing of 43 schoolchildren in grades 10-11 without pathology of the vision organ was carried out on the NS-Psychotest complex, including the method of critical flicker fusion frequency to assess the state of the central part of the visual analyzer and the response to a moving object to determine the degree of the balance in nervous processes. The influence of reading illogical texts typed by a school headset was studied with a font size of 14, 12 and 10 points and a one-time reading of 200, 400 and 600 characters. Laptop Lenovo IdeaPad 720S-15 was used for the presentation of information. Results. High-grade schoolchildren were established to have the initial fatigue both of the visual analyzer and the nervous system as a whole. Boys showed better indices of the critical flicker fusion frequency than girls. Most schoolchildren had a balanced type of the inhibition and excitement processes. Methods of presenting information in electronic textbooks were shown to affect the psychophysiological state of high schoolchildren and may carry risks to their health. The hygienically rational design of electronic educational texts promotes the optimization of the psycho-functional state of the high schoolchildren’s body. Conclusion. The obtained results allow substantiating hygienic requirements for the font design of e-learning publications at the third stage of education.


2021 ◽  
Vol 51 (2) ◽  
pp. 228-229
Author(s):  
Xavier CE Vrijdag ◽  
◽  
Hanna van Waart ◽  
Jamie W Sleigh ◽  
Simon J Mitchell ◽  
...  

2016 ◽  
Vol 157 (27) ◽  
pp. 1079-1086
Author(s):  
Orsolya Angeli ◽  
Dániel Sándor Veres ◽  
Zoltán Zsolt Nagy ◽  
Miklós Schneider

Introduction: Measurement of central critical flicker-fusion frequency is a common screening test for eye diseases and additionally it can serve as a useful diagnostic test in numerous neurological and internal diseases. The test might also be used for monitoring purposes. Aim: The aim of the authors was to evaluate a digital central critical flicker-fusion frequency measuring device (IMEA ADR III) in 30 young, healthy Hungarian subjects. Method: After a general ophthalmological screening examination, monocular central critical flicker-fusion frequency was measured with four colours. Measurements were carried out on two separate days in three sessions under standardized conditions. Intrasession, intersession and intervisit variabilities, differences in central critical flicker-fusion frequency using the four colours and the effect of certain other influencing factors were determined. Results: There were no statistically significant differences between sessions in the mean and standard deviation of the measurement sets. The central critical flicker-fusion frequency threshold for red colour was significantly lower than for other colours, and the threshold for blue colour was significantly lower than for green. There were no significant differences regarding sex, age, iris colour, and smoking indicating that these factors did not influence the central critical flicker-fusion frequency threshold in these subjects. Conclusions: Measurement results with the device are reliable and reproducible in healthy, young population in separate sessions. Orv. Hetil., 2016, 157(27), 1079–1086.


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