Critical Flicker Fusion Frequency Test Research Articles

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

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.

Association of the Val158Met Polymorphism of the COMT Gene with Measures of Psychophysiological Status in Athletes

Resistance to psychological stress, motivation, physical work capacity, and fatigue are genetically determined characteristics which are important for successful competitive activity in athletes. Polymorphism of the catechol-O-methyltransferase (COMT; regulates the function of the dopaminergic system) gene can generate individual differences in the development and manifestation of psychophysical qualities. The present study assessed the influences of the rs4680 polymorphism of the COMT gene on the psychophysiological status of 146 athletes of different specialties and qualifications. Athletes carrying the Met allele were found to have high psychological stability in the critical flicker fusion frequency test, which reflects the ability to form a task-appropriate functional system and maintain it for a longer period of time, as compared with carriers of the Val allele. Females (aged 10–19 years) showed higher rates of sensorimotor reactions in a simple visuomotor reaction test and a smaller number of accurate reactions in a moving object reaction test. Males (aged 12–19 years) carrying the Met allele were characterized by higher levels of personal anxiety on the Spielberger–Hanin anxiety scale. Thus, these studies demonstrate that the rs4680 polymorphism of the COMT gene influences the psychophysiological status of athletes.

Evaluation of Divers' Neuropsychometric Effectiveness and High-Pressure Neurological Syndrome via Computerized Test Battery Package and Questionnaires in Operational Setting.

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.

Possibilities of therapeutic correction of hyperammonemia and minimal hepatic encephalopathy in patients with chronic hepatitis C at the pre-cirrhotic stage.

Study of the social consequences of cognitive disorders in minimal hepatic encephalopathy (MHE) in patients with chronic genotype 1 hepatitis C and the possibilities of their pharmacological correction with L-ornithine-L-aspartate (LOLA, Hepa-Merz). The study group included 60 male patients diagnosed with chronic hepatitis C, genotype 1 with fibrosis stage F1 according to the METAVIR scale, and presented with MHE. The average age of the patients was 34.2±5.3 years. The control group included 20 healthy men aged 34.1±5.8 years without liver disease. Intermittent treatment with LOLA was given to the study group at 15 g once daily in the morning for 2 months with 2-month off-treatment intervals, with the total treatment duration of 12 months. In the course of treatment, MHE dynamics was assessed using the critical flicker fusion frequency (CFF) test and the number connecting test (NCT), as well as by serum concentrations of ammonium ion. The LOLA efficacy endpoint was the change in the frequency of violations of traffic rules (traffic code). A significant decrease in the concentration of ammonium ion was observed after 5 months of treatment (135.53 and 82.9 μmol/L, p=0.002) and maintained throughout the study. The results of the CFF test significantly improved by the end of the 1st month of LOLA treatment (p=0.008), remaining at the achieved level for 9 months. The NCT parameters reached their minimum values after 5 months (p&lt;0.001) and remained at this level throughout the study. During the study period, the frequency of traffic code violations by participants decreased from 60 to 40% (р=0.03). Fractional treatment with LOLA leads to a decrease in the blood concentration of ammonium ion and, consequently, to an improvement in psychometric test results and a decrease in the frequency of traffic code violations. The result achieved can have an impact on the accident rate reduction.

Critical Flicker Fusion Frequency: A Marker of Cerebral Arousal During Modified Gravitational Conditions Related to Parabolic Flights.

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.

Comparative evaluation of atorvastatin and simvastatin on critical fusion frequency in healthy volunteers

Background: Atorvastatin and simvastatin are the most frequently prescribed among statins to reduce high lipid levels. Statins are reported to alter cognitive functions. However, the results are equivocal as numbers of studies have shown improvement in the cognitive function, while others have documented impairment. Aims and Objectives: The present study was undertaken to compare the effects of atorvastatin and simvastatin on critical flicker fusion frequency (CFFF) which is a most sensitive indicator of cortical arousal. Hence, that outcome of the trial provides evidence of the alterations in cognition in unambiguous terms. Materials and Methods: A single-dose, open-label, crossover study was conducted in 15 healthy volunteers. They were familiarized on CFFF test apparatus till they attained plateau level in their values. Predrug score was recorded before giving test drug on the trial day. Volunteers were then given oral single dose of either of drug (atorvastatin 10 mg or simvastatin 10 mg) and then crossed over with 10 days washout period between both treatments. In each arm, volunteers were followed up to 6 h for the postdrug score. Results: Both atorvastatin and simvastatin decreased the CFFF significantly during the entire study period (P = 0.0001) from their respective predrug values. On comparison, both these drugs produced identical CFFF decline (P > 0.05). Conclusion: Result of current study highlights the impairment of CFFF with both of these drugs in similar manner in healthy volunteers. However, the trials with long-term treatment in patients are advised to clearly define their role in cognitive function.

Workload Influence on Fatigue Related Psychological and Physiological Performance Changes of Aviators

ObjectiveWe evaluated a variety of non-invasive physiological technologies and a series of test approaches for examination of aviator performances under conditions of mental workload in order to provide a standard real-time test for physiological and psychological pilot fatigue assessments.MethodsTwenty-one male aviators were selected for a simulated flight in a hypobaric cabin with artificial altitude conditions of 2400 meter above sea level. The simulated flight lasted for 1.5 h, and was repeated for two times with an intervening 0.5 h rest period outside the hypobaric cabin. Subjective criteria (a fatigue assessment instrument [FAI]) and objective criteria (a standing-position balance test as well as a critical flicker fusion frequency (CFF) test) were used for fatigue evaluations.ResultsNo significant change was observed in the FAI scores before and after the simulated flight, indicating that there was no subjective fatigue feeling among the participants. However, significant differences were observed in the standing-position balance and CFF tests among the subjects, suggesting that psychophysiological indexes can reflect mental changes caused by workload to a certain extent. The CFF test was the simplest and clearly indicated the occurrence of workload influences on pilot performances after a simulated flight.ConclusionsResults showed that the CFF test was the easiest way to detect workload caused mental changes after a simulated flight in a hypobaric cabin and reflected the psychophysiological state of aviators. We suggest that this test might be used as an effective routine method for evaluating the workload influences on mental conditions of aviators.

The use of Critical Flicker Fusion frequency test for evaluating some central nervous effects of two indomethacin formulations.

The use of Critical Flicker Fusion frequency test for evaluating some central nervous effects of two indomethacin formulations.

A Double-blind, Placebo- and Flurazepam-controlled Investigation of the Residual Psychomotor and Cognitive Effects of Modified Release Zolpidem in Young Healthy Volunteers

Short-acting hypnotic drugs, such as zolpidem, have minimal residual effects but may not provide optimal efficacy throughout the night for all insomnia patients. A modified-release formulation of zolpidem, zolpidem-MR, has been developed to overcome this limitation. This was a phase I, double-blind, 3-way crossover, placebo-controlled study to investigate the residual psychomotor and cognitive effects of a single oral dose of zolpidem-MR 12.5 mg in 18 healthy young adults. Flurazepam 30 mg was used as a positive control. No comparison with standard immediate-release zolpidem was made. Five neuropsychological tests and 2 subjective tests were performed 8 hours after dosing. The safety of zolpidem-MR was also investigated. Performance on the Critical Flicker Fusion Frequency test, Choice Reaction Time, Immediate and Delayed Word Recall, and the Compensatory Tracking Task was significantly impaired by flurazepam but not by zolpidem-MR (with the exception of the Compensatory Tracking Task) or placebo. No significant effects were observed on the Digit Symbol Substitution Test. The Leeds Sleep Evaluation Questionnaire showed that both drugs improved the ease of getting to sleep and perceived quality of sleep, whereas only flurazepam significantly impaired the ease of awakening. Neither drug scored significantly better than placebo on the Bond and Lader contentedness scale, but both induced a significant difference in calmness; only flurazepam significantly reduced alertness. The safety profile of zolpidem-MR was comparable to placebo. In conclusion, the study showed the good tolerance of zolpidem-MR in terms of residual neuropsychological effects as well as a beneficial effect on sleep quality in young healthy adults.

Effects of the length and timing of nighttime naps on task performance and physiological function

To examine the effects of the length and timing of nighttime naps on performance and physiological functions, an experimental study was carried out under simulated night shift schedules. Six students were recruited for this study that was composed of 5 experiments. Each experiment involved 3 consecutive days with one night shift (22:00-8:00) followed by daytime sleep and night sleep. The experiments had 5 conditions in which the length and timing of naps were manipulated: 0:00-1:00 (E60), 0:00-2:00 (E120), 4:00-5:00 (L60), 4:00-6:00 (L120), and no nap (No-nap). During the night shifts, participants underwent performance tests. A questionnaire on subjective fatigue and a critical flicker fusion frequency test were administered after the performance tests. Heart rate variability and rectal temperature were recorded continuously during the experiments. Polysomnography was also recorded during the nap. Sleep latency was shorter and sleep efficiency was higher in the nap in L60 and L120 than that in E60 and E120. Slow wave sleep in the naps in E120 and L120 was longer than that in E60 and L60. The mean reaction time in L60 became longer after the nap, and faster in E60 and E120. Earlier naps serve to counteract the decrement in performance and physiological functions during night shifts. Performance was somewhat improved by taking a 2-hour nap later in the shift, but deteriorated after a one-hour nap. Naps in the latter half of the night shift were superior to earlier naps in terms of sleep quality. However performance declined after a 1-hour nap taken later in the night shift due to sleep inertia. This study suggests that appropriate timing of a short nap must be carefully considered, such as a 60-min nap during the night shift.

Psychomotor recovery in very old patients after total intravenous or balanced anaesthesia for cataract surgery

We compared psychomotor recovery after total intravenous anaesthesia (TIVA) with remifentanil/propofol and balanced anaesthesia (BAL) with etomidate/fentanyl/isoflurane in 40 patients, ASA I-III, aged > or =80 yr undergoing elective cataract surgery. Recovery times were recorded and psychomotor recovery was assessed according to simple reaction time, critical flicker fusion frequency (CFF) and short-term memory 30 min, 2 h and 1 day after surgery. Physical characteristics of patients in the two groups (19 in the TIVA group and 21 in the BAL group) were comparable. The TIVA group recovered significantly more quickly. Both groups showed a poorer psychomotor performance 30 min after surgery than at baseline assessment, but simple reaction time and short-term memory were close to baseline values 2 h after surgery. Only performance in the CFF test remained below baseline at this point. No deficits in psychomotor performance were noted on the first day after surgery. We conclude that there is only a minor deficit in psychomotor function in elderly patients 2 h after cataract surgery under general anaesthesia and that psychomotor function recovers completely by 24 h after surgery.

Effect of Work Posture on Fatigue of Female Laborers

The purpose of this study is to investigate the difference in fatigue phenomena, by changing work postures in order to impove working condition of female laborers doing monotonous work in a standing posture.The work posture so far taken is 'standing', and those taken in our experiment are 'standing with buttock rest' and 'sitting'. In examining the subjective fatigue symptoms, the laborers who worked 'standing' and who worked 'standing with buttock rest' made tendentiously higher complaints than those who worked 'sitting'. The performance of the former were significantly higher than those of the latter. In CFF (Critical Flicker Fusion Frequency) and patellar reflex test nosignificant difference was made by work postures. In CFF they all took the patterns peculiar to monotonous work. Estimations of %Vo2 max. were 20.7% (standing), 19.4% (standing with buttock rest) and 16.7% (sitting); There was significant difference between 'standing' and ' sitting'.The result of these experiments suggest that sitting work gives lighter load work than the others, but than it showed significantly lower performances.