Critical Flicker Fusion Research Articles

Assessment of Sleep Deprivation and Fatigue Among Chemical Transportation Drivers in Chonburi, Thailand.

BackgroundFatigue and sleepiness are inter-related and common among road transport drivers. In this study, sleep deprivation and fatigue among chemical transportation drivers were examined.MethodsA cross-sectional study surveying 107 drivers from three hazardous types of chemical production and transportation industries (nonflammable gases, flammable gases, and flammable liquids) was conducted. Data on sleep deprivation were collected using questionnaires of the Stanford Sleeping Scale and the Groningen Sleep Quality Scale. Fatigue was assessed using an interview questionnaire and a flicker fusion instrument.ResultsChemical drivers had a mean sleeping scale (Stanford Sleeping Scale) of 1.98 (standard deviation 1.00) and had a mean score of 1.89 (standard deviation 2.06) on the Groningen Sleep Quality Scale. High-risk drivers had higher scores in both the Stanford Sleeping Scale and the Groningen Sleep Quality Scale with a mean score of 2.59 and 4.62, respectively, and those differences reached statistical significance (p < 0.05). The prevalence of fatigue, as assessed through a critical flicker fusion analyzer, subjective fatigue question, and either of the instruments, was 32.32%, 16.16%, and 43.43%, respectively. Drivers who slept <7 hours and had poor sleep quality were found to have more fatigue than those who slept enough and well. Drivers who had a more sleepiness score resulted in significantly more objective fatigue than those who had a less sleepiness score.ConclusionSleep quality and sleeping hour can affect a driver's fatigue. Optimization of work–rest model should be considered to improve productivity, driver retention, and road safety.

EXPLORING NOVEL COGNITIVE AND ELECTROPHYSIOLOGICAL MARKERS OF TARGET ENGAGEMENT IN PHASE 1 AND 2 STUDIES OF PUTATIVE CHOLINERGIC COGNITIVE ENHANCERS

Loss of cholinergic signaling is principally related to cognitive decline in Alzheimer's Disease (AD), and stimulation of these receptors improves cognitive performance. While acetylcholinesterase inhibitors are modestly helpful in the early stages of AD, neurodegeneration limits their effectiveness, and warrants the development of alternative cholinergic treatments. Given the high costs of drug development, it is important to obtain evidence of target engagement as early as possible. Phase 1 and 2 studies provide an opportunity not only to establish maximum tolerated doses and safety, but also to document cognitive effects in human subjects. Development of novel behavioral and brain-based measures targeting cognitive processes of interest and sensitive to the drug effects will accelerate efficacy evaluation. We report evidence from early phase drug trials using event-related potentials (ERP) and cholinergically-responsive psychomotor cognitive tasks developed in our laboratory as markers of CNS engagement. We explored whether treatment may potentiate cholinergic receptors in the CNS in humans by evaluating changes in electroencephalography (EEG) functions (e.g. altered ERPs). Oddball and memory ERP tasks were used to evaluate the cognitive impact of four-week chronic nicotine treatment on memory (indexed by increased ERP amplitudes for repeated vs. novel stimuli and better performance on a Selective Reminding Task) in aging adults with Down syndrome (DS), a single-gene model of AD. ERP passive memory testing demonstrated positive drug effects on cognitive performance compared to standard verbal memory tasks that were difficult for DS subjects to perform. In addition, computerized cognitive assessment of basic sensory and psychomotor functions utilizing critical flicker fusion and decomposition of choice reaction time detected subtle cognitive effects of cholinergic agents in volunteers. We are currently using the same ERP and sensory/psychomotor measures to examine the effects of a novel cholinergic positive allosteric modulator (PAM) to establish functional biomarkers of central target engagement in healthy young adults.

Color-Shift Keying—How Its Largest Obtainable “Minimum Distance” Depends on Its Preset Operating Chromaticity and Constellation Size

Color-shift keying (CSK) is a type of visible light wireless communication, where a visible color is preset and is to appear constant during the human vision's “critical flicker fusion threshold” and “critical color fusion threshold.” This paper is first in the open literature to systematically investigate how CSK's largest achievable “minimum distance” ( $d_{\min }$ ) would vary with the preset chromaticity and with the constellation size ( $M$ ). This paper discovers this elegant approximation: The best $d_{\min } \approx 1.921M^{-0.5985} - 2.736M^{-0.645} (\tilde{x}^2 + \tilde{y}^2)^{0.7802(\log _{2}M)^{-0.436} }$ , where $(\tilde{x}, \tilde{y})$ refers to the preset chromaticity's displacement (in a two-dimensional space) from the case of all LEDs emitting with an equal intensity.

Macular Carotenoid Supplementation Improves Visual Performance, Sleep Quality, and Adverse Physical Symptoms in Those with High Screen Time Exposure

The dramatic rise in the use of smartphones, tablets, and laptop computers over the past decade has raised concerns about potentially deleterious health effects of increased “screen time” (ST) and associated short-wavelength (blue) light exposure. We determined baseline associations and effects of 6 months’ supplementation with the macular carotenoids (MC) lutein, zeaxanthin, and mesozeaxanthin on the blue-absorbing macular pigment (MP) and measures of sleep quality, visual performance, and physical indicators of excessive ST. Forty-eight healthy young adults with at least 6 h of daily near-field ST exposure participated in this placebo-controlled trial. Visual performance measures included contrast sensitivity, critical flicker fusion, disability glare, and photostress recovery. Physical indicators of excessive screen time and sleep quality were assessed via questionnaire. MP optical density (MPOD) was assessed via heterochromatic flicker photometry. At baseline, MPOD was correlated significantly with all visual performance measures (p < 0.05 for all). MC supplementation (24 mg daily) yielded significant improvement in MPOD, overall sleep quality, headache frequency, eye strain, eye fatigue, and all visual performance measures, versus placebo (p < 0.05 for all). Increased MPOD significantly improves visual performance and, in turn, improves several undesirable physical outcomes associated with excessive ST. The improvement in sleep quality was not directly related to increases in MPOD, and may be due to systemic reduction in oxidative stress and inflammation.

Seeing is believing: a demonstration of critical fusion frequency and its multidimensional nature.

critical fusion frequency (CFF), or the flicker fusion threshold, is defined as the critical frequency above which a flickering light source appears steady to the observer (see [Fig. 1][1]). It is known to depend on a number of parameters, namely, intensity of the light source ([5][2], [15][3]),

Residual effects of eszopiclone and placebo in healthy elderly subjects: a randomized double-blind study

Next-day residual effects are a common problem with current hypnotics. The purpose of the present study was to evaluate the residual effects of eszopiclone on the physical and cognitive functions of healthy elderly people in the early morning and the day following drug administration. Four men and six women aged 63–72 years were administered eszopiclone 1 mg or placebo in a randomized, double-blind and crossover design. Measures of objective parameters and subjective ratings were obtained at 4:00, 6:00, and every 2 h from 6:00 to 16:00 hours. For the timed up-and-go test, the main effects of time were seen. For the critical flicker fusion, eszopiclone had significantly worse results compared to placebo in early morning (4:00). There were no significant differences between eszopiclone and placebo in other objective assessments. For the sleep latency, eszopiclone had significantly shorter results compared to placebo (eszopiclone vs placebo = 28.4 vs 52.5 min, p = 0.047). Feeling of deep sleep and the number of wake after sleep onset did not show any significant differences between eszopiclone and placebo. Based on the above results, the changes of physical and cognitive functions in the healthy elderly after taking hypnotics, it was found that eszopiclone 1 mg is likely to be unharmful for the healthy elderly. Further studies of elderly insomniacs with midnight awakenings are needed.

Study of Critical Flicker Fusion (CFF) Function and P100 latency of Visual Evoked Potential (VEP) in Normal subjects and Patients who Recovered from Acute Optic Neuritis

Study of Critical Flicker Fusion (CFF) Function and P100 latency of Visual Evoked Potential (VEP) in Normal subjects and Patients who Recovered from Acute Optic Neuritis

Prevalence of Fatigue and Its Determinants among Chemical Transportation Drivers in Chonburi

Driver fatigue is a recognized risk factor for commercial road transport industry drivers. The aim of this cross-sectional research was to assess the fatigue and its determining factors among 99 chemical transportation drivers in Chonburi. Driving fatigue was assessed by both subjective questionnaire (n = 99) and flicker fusion instrument (n = 88). The association between driving fatigue and related factors were analyzed by Pearson’s correlation and Chi-square (χ2). The results revealed that the prevalence of fatigue as assessed by critical flicker fusion analyzer, subjective fatigue question and either one of the instruments were 32.32 %, 16.16 % and 43.43 %, respectively. Multiple regression analysis indicated that the predictive factors of objective fatigue were alcohol drinking, musculoskeletal disorder and road accident history. The results suggest thatscreening for alcohol use and musculoskeletal disorders was further needed for policy settings and routine checks.

Derivation of Decision Algorithms for the Diagnosis of Hepatic Encephalopathy in Patients With Cirrhosis

Introduction: The presence of hepatic encephalopathy (HE), whether minimal or overt has a significant detrimental effect on patients’ quality of life, safety and survival. Current diagnostic tests are poorly validated or else are not generally applicable or practical for use in the clinical setting. This aim of this study was to identify simple, accurate algorithms for the diagnosis of HE in patients with cirrhosis that can be used in both clinical and research settings. Methods: Fifty-one patients with cirrhosis (30 men, 21 women; mean [range] age of 57.1 [24–81] years) were classified using clinical, psychometric and electroencephalographic variables, as either neuropsychiatrically unimpaired (n = 24), or as having minimal (n = 18) or overt (n = 9) HE. Patients’ neuropsychiatric status was further assessed using a series of alternative tests including: animal naming, Critical Flicker Fusion Frequency (CFF); Inhibitory Control Test (ICT); the SCAN package, and the Stroop test. Reference data were obtained from 61 healthy individuals (21 men, 40 women; mean age 46.4 [20–70] years). Thresholds for the diagnosis of any degree of HE were identified using receiver operating curve characteristics analysis. Diagnostic algorithms for use in clinical and research settings were then constructed using a Classification and Regression Tree growing method. Results: The Stroop test performed best overall; 80% of its generated variables separated healthy controls from patients with both minimal and overt HE. The single best variable was a combined score of the multiple variables from the SCAN package: sensitivity of 95.8% and specificity of 70.1%. An algorithmic construct, consisting of the ICT, SCAN package, and Stroop test, classified patients with a sensitivity of 92.6% and a specificity of 89.4% (Figure 1A). A modified algorithm, utilizing the Stroop test and the EEG, which would be more applicable in the clinical setting, had a sensitivity of 88.9% and a specificity of 94.7% (Figure 1B). Discussion: The derived algorithms have significantly better diagnostic performance than the individual tests currently used. They can be used in the clinical setting for: (i) the initial assessment of patients with cirrhosis to ensure they receive a diagnosis that may otherwise be overlooked thereby allowing them to receive treatment, if required; (ii) confirming the diagnosis of HE where this is in dispute; and, (iii) evaluating suitability for a transjugular intrahepatic portosystemic shunt procedure. In a research setting the derived algorithms will provide a diagnostic standard that is universally applicable. Further validation in independent cohorts of patients is clearly required. The authors have none to declare.

Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue

The purpose of this study was to determine whether subjects who wear short wavelength-blocking eyeglasses during computer tasks exhibit less visual fatigue and report fewer symptoms of visual discomfort than subjects wearing eyeglasses with clear lenses. A total of 36 healthy subjects (20 male; 16 female) was randomized to wearing no-block, low-blocking, or high-blocking eyeglasses while performing a 2-hour computer task. A masked grader measured critical flicker fusion frequency (CFF) as a metric of eye fatigue and evaluated symptoms of eye strain with a 15-item questionnaire before and after computer use. We found that the change in CFF after the computer task was significantly more positive (i.e., less eye fatigue) in the high-block versus the no-block (P = 0.027) and low-block (P = 0.008) groups. Moreover, random assignment to the high-block group but not to the low-block group predicted a more positive change in CFF (i.e., less eye fatigue) following the computer task (adjusted β = 2.310; P = 0.002). Additionally, subjects wearing high-blocking eyeglasses reported significantly less feeling pain around/inside the eye (P = 0.0063), less feeling that the eyes were heavy (P = 0.0189), and less feeling that the eyes were itchy (P = 0.0043) following the computer task, when compared to subjects not wearing high-blocking lenses. Our results support the hypothesis that short-wavelength light-blocking eyeglasses may reduce eye strain associated with computer use based on a physiologic correlate of eye fatigue and on subjects' reporting of symptoms typically associated with eye strain.

Retinal temporal resolution and contrast sensitivity in the parasitic lamprey Mordacia mordax and its non-parasitic derivative Mordacia praecox.

Lampreys and hagfishes are the sole extant representatives of the early agnathan (jawless) vertebrates. We compared retinal function of fully metamorphosed, immature Mordacia mordax (which are about to commence parasitic feeding) with those of sexually mature individuals of its non-parasitic derivative Mpraecox We focused on elucidating the retinal adaptations to dim-light environments in these nocturnally active lampreys, using electroretinography to determine the temporal resolution (flicker fusion frequency, FFF) and temporal contrast sensitivity of enucleated eyecups at different temperatures and light intensities. FFF was significantly affected by temperature and light intensity. Critical flicker fusion frequency (cFFF, the highest FFF recorded) of M. praecox and M. mordax increased from 15.1 and 21.8 Hz at 9°C to 31.1 and 36.9 Hz at 24°C, respectively. Contrast sensitivity of both species increased by an order of magnitude between 9 and 24°C, but remained comparatively constant across all light intensities. Although FFF values for Mordacia spp. are relatively low, retinal responses showed a particularly high contrast sensitivity of 625 in M. praecox and 710 in M. mordax at 24°C. This suggests selective pressures favour low temporal resolution and high contrast sensitivity in both species, thereby enhancing the capture of photons and increasing sensitivity in their light-limited environments. FFF indicated all retinal photoreceptors exhibit the same temporal response. Although the slow response kinetics (i.e. low FFF) and saturation of the response at bright light intensities characterise the photoreceptors of both species as rod-like, it is unusual for such a photoreceptor to be functional under scotopic and photopic conditions.

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.

Effect of Cellular Mobile Phone Use and Cetrizine on Hand-Eye Coordination and Visual Acuity.

Cellular mobile phones are a major cause of distraction especially while driving. The aggressive and inappropriate use of cellular mobile phones has increased the risk of accidents. Similar alerts are available in literature for certain substances and drugs (e.g. second generation anti H1 drug -Cetirizine) which also derange psychomotor performance and parameters of alertness. This study measured variations in hand-eye coordination and visual acuity due to use of cellular mobile phone in comparison to that of commonly used antihistaminic drug viz., single dose Cetirizine 10 mg. It was a single blind, single dose, interventional study, 100 healthy human volunteers divided into two groups. Baseline readings of all volunteers were noted. Group-I (n=50) was Cetirizine group (10mg orally stat), Group -II (n=50) Cellular mobile phone user group. Alertness was tested on hand- steadiness tester (Reaction Time Index = RTI) and on Flicker-fusion apparatus (visual acuity - Critical Flicker Fusion Frequency per second= CFFF/sec). Baseline readings of all volunteers were noted before intervention. Baseline was compared with readings at three hour post-intervention and was analysed by paired t-test. Inter-group comparison of parameters was also done and was analysed by unpaired t-test. The baseline RTI (95.46±41.74, 85.11±39.05) and CFF low and high (40.07±9.970, 40.76±9.309 and 40.42±9.035, 40.48±9.863) respectively, in Cetirizine group and Mobile user group were comparable. The RTI increased significantly (116.4±51.46, 102.8±49.26) in both the groups after intervention. However, there is no significant change in CFF intensity from baseline in either group post-intervention. Concurrent use of mobile phone while performing tasks, showed significant impairment of hand-steadiness which was comparable to that produced by single dose Cetirizine 10 mg and this may be one of the factors contributing to their close association with road traffic accidents.

Visual function and retinal vessel diameters during hyperthermia in man.

To assess the effect of elevated core body temperature on temporal and spatial contrast sensitivity and retinal vessel diameters. The study included 13 healthy volunteers aged 20-37years. Core body temperature elevation (target +1.1°C) was induced by wrapping the participants in cling film, tinfoil and warming blankets. Subsequent cooling was achieved by undressing. Flicker sensitivity (critical flicker fusion frequency) was chosen to assess temporal resolution, while the Freiburg Vision Test was used to determine spatial contrast sensitivity at 1.5 cycles per degree. Scanning laser ophthalmoscopy was used to measure retinal trunk vessel diameters. Assessment was made at baseline, during hyperthermia and after cooling. The induction of a mean increase in core body temperature of 1.02°C was associated with a 7.15-mmHg mean reduction in systolic blood pressure (p<0.01), a 10.6-mmHg mean reduction in diastolic blood pressure (p<0.01), a mean increase in pulse rate of 36.3bpm (p<0.0001), a 2.66% improvement in flicker sensitivity (CI95 1.37-3.94, p<0.001), a 2.80% increase in retinal artery diameters (CI95 1.09-4.51, p<0.01) and a 2.95% increase in retinal vein diameters (CI95 0.96-4.94, p<0.01). There was no detectable effect of temperature on spatial contrast sensitivity. All ocular test parameters returned to baseline levels after cooling. Increased core body temperature was accompanied by improved temporal visual resolution and retinal trunk vessel dilation. The results suggest that hyperthermia is associated with enhanced retinal function and increased retinal metabolism.

The Application of Cortical Arousal Assessment to Control Neuromuscular Fatigue During Strength Training

ABSTRACTThe author's aim was to analyze the cortical arousal response during a conventional strength training session as a method to assess central nervous system fatigue. Sixteen trained men were recruited to perform the maximum number of training series composed of 6 exercises of 10 repetition each, at the intensity of 70% of the 1 maximum repetition, with a rest period of 2 min between exercises and 5 min between series, until exhaustion. Cortical arousal was measured using the critical flicker fusion threshold before, after warm-up, after each exercises series, after the recovery phase between series, and 15 min and 30 min after finishing the training session. Participants could not finish the fourth series of exercise, corresponding with a significant decrease of cortical arousal respect to the warm-up value. The assessment of cortical arousal using CFFT during a strength training session could be a fast and efficient method for assessing central nervous fatigue. Practically, coaches could modify the training protocol according to the individual cortical arousal response in order to improve training efficiency and prevent injuries.

Two Visual Training Paradigms Associated with Enhanced Critical Flicker Fusion Threshold.

Critical flicker fusion thresholds (CFFTs) describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision-training approaches, one involving contrast sensitivity training and the other directional dot-motion training, compared to an active control group trained on Sudoku. The three training paradigms were compared on their effectiveness for altering CFFT. Directional dot-motion and contrast sensitivity training resulted in significant improvement in CFFT, while the Sudoku group did not yield significant improvement. This finding indicates that dot-motion and contrast sensitivity training similarly transfer to effect changes in CFFT. The results, combined with prior research linking CFFT to high-order cognitive processes such as reading ability, and studies showing positive impact of both dot-motion and contrast sensitivity training in reading, provide a possible mechanistic link of how these different training approaches impact reading abilities.

Responsive upper limb and cognitive fatigue measures during light precision work: an 8-hour simulated micro-pipetting study

Many contemporary occupations are characterised by long periods of low loads. These lower force levels, which are relevant to the development of work-related musculoskeletal disorders, are usually not the focus of fatigue studies. In studies that did measure fatigue in light manual or precision work, within and between measurement responses were inconsistent. The aim of this study was to identify fatigue measures that were responsive at lower force levels (<10% MVC) over the course of an 8-h period. A complementary set of fatigue measures, reflecting both neuromuscular and cognitive mechanisms, was measured during a light precision micro-pipetting task performed by 11 participants. Nine measures were found to be significantly responsive over the 8-h period, including: ratings of perceived fatigue, postural tremor, blink frequency and critical flicker fusion frequency threshold. Common field measures, specifically electromyography RMS amplitude and maximum voluntary contractions, did not lead to extraordinary time effects.Practitioner summary: The findings provide insight towards the responsiveness of a complementary set of field usable fatigue measures at low work intensities Although commonly used measures did not reveal significant increases in fatigue, nine alternative measures were significantly responsive over the 8-h period.

Do Environmental Conditions Contribute to Narcosis Onset and Symptom Severity?

Although many factors contributing to inert gas narcosis onset and severity have been put forward, the available evidence is not particularly strong. Using objective criteria, we have assessed brain impairment associated with narcosis under various environmental diving conditions. 40 volunteers performed a no-decompression dive (33 m for 20 min) either in a dry chamber, a pool or open sea. They were assessed by critical flicker fusion frequency before the dive, upon arriving at depth, 5 min before ascent, on surfacing and 30 min post-dive. Compared to the pre-dive value, the mean value of each measurement was significantly different. An increase of flicker fusion to 105.00±0.69% when arriving at depth is followed by a decrease to 94.05±0.65%. This impairment persists when surfacing and 30 min post-dive, decreasing further to 96.36±0.73% and 96.24±0.73%, respectively. Intragroup comparison failed to demonstrate any statistical difference. When objectively measured narcosis may not be influenced by external factors other than pressure and gas. This might be of importance for training to avoid any over- or underestimation of the severity of narcosis based only on subjective symptoms.

FUNCTIONAL STATUS OF ATHLETS ANALYSIS UNDER THE ADAPTATION TO THE CYCLIC KIND OF SPORTS TRAINING LOADS

Непрерывное повышение спортивной результативности предъявляет всевозрастающие требования к качеству тренировочного процесса. Его совершенствование зависит от наличия устойчивой обратной связи между тренировочными воздействиями и адекватной реакцией на них организма спортсмена. В статье рассматриваются подходы комплексного исследования функционального состояния, на основе изучения его отдельных компонентов, в процессе подготовки юных лыжников и конькобежцев. Цель. Статья посвящена актуальному вопросу в работе тренеров – оценка функционального состояния организма юных спортсменов на основе изучения психического, нейродинамического, энергетического и двигательного компонентов. Метод и методология проведения работы. Основу исследования составляют: – тест «Простая зрительно-моторная реакция» (ПЗМР) до физической нагрузки и после нагрузки, характеризующий уровень возбудимости ЦНС и скорости распространения возбуждения по нервным цепям; – тест «Критическая частота слияния мельканий» (КЧСМ) до физической нагрузки и после нагрузки, – тест «Устойчивость корковых процессов» (УКП), Изучение функционального состояния ЦНС осуществлялось с помощью аппаратно-программного комплекса «НС-психотест», включающего программное обеспечение для IBM PC под управлением Windows и внешний высокоточный контроллер. Для оценки психического компонента исследовалось логическое мышление, внимание (таблица Шульта-Платонова) и память. Энергетический компонент исследовался с помощью теста Руфье. Результаты. Результат работы заключается в том, что выбор указанных методик определения функционального состояния спортсменов является оправданным, так как выявлены различия в исследуемых компонентов функционального состояния лыжников и конькобежцев. Это обусловлено различием спортивных специализаций, в каждой из которых механизмы энергетического обеспечения двигательных режимов различаются. Область применения результатов. Результаты исследования важны для организаторов тренировочного процесса молодых атлетов в циклических видах спорта. Данное исследование может послужить дальнейшему совершенствованию тренировочного процесса в циклических видах спорта.

Ergonomic evaluation of video game playing

This study investigated the effect of display type, play-rest schedule and game type on visual fatigue, heart rate and mental workload for both genders during 1 h of Wii game playing. Twenty subjects participated in the experiment. Two display types (a 32-in CRT display and a 32-in plasma display), two different play-rest schedules (10 min play with 5 min rest, repeated four times; 20 min play with 10 min rest, repeated two times) and two Nintendo “Wii Sports” games (boxing and tennis) were used for evaluation. The study results showed that the display and game type had a significant effect on all the measurements. The use of a plasma display to play video games improved the critical flicker fusion (CFF) frequency threshold; however, it also caused a greater subjective eye-fatigue rating, increased heart rate, as well as higher mental workload. Subjects with a 5-min break for every 10 min played had a lower subjective eye-fatigue rating, heart rate and mental workload than with a 10-min break for every 20 min played. The gender effect was not significant on any of the measurements. Implications of the results regarding video-game playing are discussed in terms of display and game type. Playing video games with frequent short breaks is suggested for reducing visual fatigue, especially for intensive video games.