Human Vigilance Research Articles

?A good odour to breathe?? The effect of pleasant ambient odour on human visual vigilance

The present study examined the effect of an alerting and a relaxing odour on human visual vigilance. Three groups of undergraduates (N = 54) completed a sustained visual vigilance task which required them to respond whenever a target stimulus appeared on a computer monitor. One group completed the task in the presence of an alerting odour (peppermint), another did so in the presence of a relaxing odour (bergamot) and a third group completed the task in an unscented environment. A 2×3×2 (sex×odour×diurnal preference) MANOVA was performed in order to determine group differences in response times and number of correct detections. Participants in the bergamot condition detected fewer targets correctly within 1.25 seconds of the target appearing than did those in the peppermint or no-odour groups. Exposure to bergamot was also associated with significantly fewer correct detections in the second than in the first half of the task, when compared with the other two conditions. The results suggest that sustained exposure to a relaxing odour can impair visual vigilance. Copyright © 2001 John Wiley & Sons, Ltd.

Coherent oscillations and short-term plasticity in corticothalamic networks

The neocortex and thalamus are a unified oscillatory machine. Different types of brain rhythms, which characterize various behavioral states, are combined within complex wave-sequences. During the stage of sleep that is associated with low-frequency and high-amplitude brain rhythms, the excitatory component of a cortically generated slow oscillation is effective in triggering thalamically generated rhythms and in increasing their spatiotemporal coherence over widespread territories. Thus, the study of coherent oscillations, as they appear naturally during states of vigilance in animals and humans, requires intact-brain preparations in which the neocortex and thalamus engage in a permanent dialog. Sleep oscillations are associated with rhythmic spike-bursts or spike-trains in thalamic and cortical neurons, which lead to persistent excitability changes consisting of increased depolarizing responses and decreased inhibitory responses. These short-term plasticity processes could be used to consolidate memory traces acquired during wakefulness, but can also lead to paroxysmal (hypersynchronous) episodes, similar to those observed in some epileptic seizures.

Activation of human visual cortex and alertness level - using 24-Channel mapping of Near infrared spectroscopy -

Activation of human visual cortex and alertness level - using 24-Channel mapping of Near infrared spectroscopy -

Relation of cerebral blood flow velocity and level of vigilance in humans.

Blood flow velocities in both middle cerebral arteries (MCA) were measured using transcranial Doppler ultrasound (TCD) in healthy subjects engaged in a continuous static visual vigilance task. Stimuli comprised white vertical gratings on a black background with a size of 5 x 5" (non-targets) or 5 x 3.5" (targets). Button presses were required to the rare (8.5%) targets. Over the 30 min session a decrease in hit rate and an increase in reaction time were seen, indicating a decrease in vigilance. These performance changes were paralleled by a decrease in flow velocity in both MCAs. No hemispheric difference was seen. These data suggest a close coupling of performance and blood flow in vigilance tasks. Modulation of cholinergic activity during the vigilance task might be the common underlying mechanism.

Effects on eye movements of requiring an immediate reporting response during human vigilance.

12 subjects performed a vigilance task in which signals were presented in two squares of a display according to two variable-time schedules. The subjects reported any detections of the signals by pressing a key. Latencies of the reported responses should be less than 0.3 sec. or 1.2 sec. to be reinforced. Half of the subjects were informed of the signal frequencies while the other half were not. The former subjects showed longer durations of fixation for the squares providing more signals. Such differentiations were larger under the 0.3-sec, condition than the 1.2-sec. condition. The latter group of subjects showed neither of these effects. The results suggested that different degrees of immediacy of responding might engender different patterns of eye movements.

Sensitization–habituation may occur during operant conditioning.

Operant response rates often change within experimental sessions, sometimes increasing and then decreasing. The authors attribute these changes to sensitization and habituation to aspects of the experimental situation presented repeatedly (e.g., reinforcers) or for a prolonged time (e.g., the experimental enclosure). They describe several empirical similarities between sensitization-habituation and within-session changes in operant responding. They argue that many alternative explanations for within-session changes in operant responding can be dismissed. They also examine some implications of linking the literatures on habituation and operant responding. Because responding follows a similar pattern in several other cases (e.g., human vigilance, classical conditioning, and unconditioned responding), 2 relatively simple processes may be responsible for the temporal patterning of behavior in a wide variety of situations. We observed large changes in response rate within experimental sessions when subjects (e.g., rats) responded on operant conditioning procedures (e.g., McSweeney, Hatfield, & Allen, 1990). In many of our experiments, response rates increased to a peak and then decreased. In other experiments, response rates increased without decreasing or decreased without increasing. Figure 1 contains an example of each of these types of changes. The top represents results for rats pressing levers on multiple variable interval (VI) 60-s VI 60-s schedules; the middle, the results for rats pressing levers on a VI 15-s schedule; and the bottom, the results for pigeons pecking keys on a variable ratio (VR) 15 schedule. Each graph represents the proportion of total-session responses during successive 5-min intervals in the session. Throughout this article, we calculated proportions by dividing the number of responses during a 5-min interval by the total number of responses during the session. Although within-session changes in operant responding have been observed in the past (e.g., McSweeney & Roll, 1993), these changes have been treated as problems to control by procedures, such as giving warmup trials (e.g., Hodos & Bonbright, 1972) or time to adapt to the apparatus (e.g., Papini & Overmier, 1985), rather than as phenomena to study. Further consideration suggests that within-session changes deserve study in

Evaluation of the Human Alertness and It's Applications

Evaluation of the Human Alertness and It's Applications

Effects of toluene inhalation on detection of auditory signals in rats

Inhalation of organic solvents can affect vigilance and reaction time in humans. An animal model of vigilance was designed to assess the effects of toluene on these processes. Adult male Long-Evans rats were trained to detect auditory signals (20-msec increases in the intensity of white noise). Two to 4 s after each signal (or blank period), two retractable levers were inserted into the test chamber. A press on one lever after a signal and on the other lever after a blank resulted in the delivery of food. Signal detection analysis showed that sensitivity (Sensitivity Index, SI) and response bias (Responsivity Index, RI) increased with signal intensity, indicating that loud signals were more detectable than soft signals and that the animals' criterion for responding “signal” increased with signal intensity. Response latency for correct choices was faster for signal trials than for blank trials. Toluene vapor was added to the airstream of these chambers at concentrations of 0, 1000, 1500, or 2000 ppm, either 10 or 30 min before testing and for the duration of each 1-h test. In air, SI increased across the duration of the test; this within-session improvement was reversed by toluene. RI did not change in air; it was decreased by toluene at the beginning of each exposure session, returned to the control level during exposure to 1000 and 1500 ppm toluene and exceeded air control after 40 min exposure to 2000 ppm toluene. Latency increased monotonically across toluene concentrations and time on test. Neither signal intensity nor the duration of toluene exposure before testing altered these effects of toluene. SI, RI, and latency baselines were recovered after toluene exposure indicating that no persistent effects of toluene were detectable. This conclusion was supported by data from other rats showing that toluene exposure (2000 ppm for 2 h/day for 4 consecutive days) did not affect auditory thresholds, as determined by reflex modification of an acoustic startle response using a 16 kHz tone as a prepulse stimulus, 7 or 17 days after exposure to toluene. Finally, rats tested immediately or 20 min after exposure to 0, 1000, 1500, or 2000 ppm toluene were not affected by the vapor, indicating that the impairment observed during toluene inhalation did not persist beyond the period of exposure.

Human vigilance in railway and long-haul flight operation.

Human operators in transport operations are often confronted with monotony, boredom, and irregular work schedules. This situation has become increasingly more acute because of the growing automation of systems. This paper presents methodology and preliminary results for two field studies on the vigilance of train drivers and long-range aircrews. The aim of these studies was to identify factors that can modify vigilance and to elaborate several specific solutions for reactivation. The method is based on the collection of physiological data in the field and on task observation of the operators. The recorded physiological data (EEG, EOG, EKG) permit an evaluation of vigilance and mental workload. The rest-activity cycles are estimated by actometry. The use of EEG and EOG are discussed in relation to monotony and sleep deprivation. For pilots, results show a high occurrence of decreased vigilance, particularly during phases of low workload (i.e., when cruising). Furthermore, it was shown that these periods of lowered vigilance can occur at the same time for two crew members. A great number of incidents of decreased vigilance were also observed for the train drivers. These incidents occurred even though the operators sometimes had high levels of activity. A direct relation was also noted between sleep duration and the onset of rest. These studies provide several means for maintaining vigilance during activities and improving the system of work schedule rotation.

生体の活性度評価とその応用

生体の活性度評価とその応用

Office Anesthesia Monitoring

SUMMARY It is universally agreed that no electronic device could ever replace human vigilance or knowledge in maintenance of high-quality anesthesia care. Nevertheless, it is accepted practice that all patients be monitored continually when anesthetic agents are employed. The American Society of Anesthesiologists' standards for basic intraoperative monitoring include the presence of qualified anesthesia personnel throughout the conduct of all general anesthetics, regional anesthetics, and monitored anesthesia care and continual evaluation of the patient's oxygenation, ventilation, circulation, and temperature during all anesthetics. The Committee on Anesthesia of the AAOMS has chosen not to dictate monitoring techniques, nor has it chosen to set a “standard of practice” for monitoring.1 The Committee does, however, suggest guidelines that parallel the standards established by the ASA. Surgeons accept monitoring as part of routine office surgery. This monitoring at the very least includes recording of blood pressures, respiratory rate, and heart rate, which at times is more qualitative than quantitative. Today we do not have ideal mechanical monitoring devices but rather devices that accu-rately measure and record a patient's vital functions automatically at brief intervals. Literally hundreds of devices exist in the marketplace, quality and cost spanning a wide range. Required equipment includes (1) noninvasive blood pressure device, (2) ECG and defibrillator, (3) pulse oximeter, and (4) temperature recording device. Coexistent with the use of more sophisticated devices is the necessity to understand how they work and what parameters require intervention. Finally, what will the near future hold? Most likely capnography will be applied to the sedated patient via a nasal prong device to give us a more instantaneous evaluation of hypoventilation. As we advance through the 1990s, standardization will lead to better patient outcomes and probably reductions in malpractice premiums as experienced by anesthesiologists in the 1980s. As has been pointed out in an editorial by Laskin,6 we have a very long and safe history of practicing ambulatory anesthesia in our office surgical practices. We can only expect this to get better.

Effects of tianeptine on vigilance and memory in young healthy volunteers

SummaryTianeptine is a new antidepressant that, in animals, has a faciliting effect on both working and reference memory. To investigate the effects of tianeptine on vigilance and memory in humans, a placebo-controlled cross-over study was performed in 20 healthy volunteers. The duration of each treatment period was 7 days and the dosage of tianeptine 37.5 mg per day. The evaluations consisted of 3 computerized tests assessing alert function, continuous recognition and semantic facilitation. A memory questionnaire and the Rey test (15 words) were added. The analysis of variance (cross-over type) performed on the results did not show any significant difference between the evolution of these tests on tianeptine and on placebo in young healthy subjects, at the height of their intellectual capacities. In this study, tianeptine respected the vigilance as well as the performances of the healthy volunteers and did not impair their memory and cognitive processes, which distinguishes it from many psychotropic drugs. Nevertheless, tianeptine did not produce a faciliting effect on these processes in healthy volunteers. These results allow us to propose new clinical trial with tianeptine in order to investigate its effects on older volunters and patients complaining of memory disorders.

Ethanol's effect on human vigilance during a simple task in the presence of an auditory stressor.

This study concerns the effect of ethanol on vigilance during a simple task. A “complete-the-picture” test was administered to 128 male college students. Subjects ingested either a placebo or a moderate dose of alcohol, and half were assigned to complete the task with a stressor, static noise, included in the test environment. The time spent on the task and the number of details sketched by each subject were measured. Moderate doses of alcohol appear to dampen peripheral stressors and allow attention toward a central, simple task to be maintained or increased.

Application of vigilance research: rare, medium, or well done?

Despite a history of over 40 years and a vast amount of experimentation, vigilance research has not had a palpable impact on real-world systems. The problem has been blamed in part on the types of studies and the range of variables that have been chosen, but this is only part of the picture. The failure of implementation can also be attributed to insufficient interest in bridging the gap between the laboratory and the work world and lack of data from not the former but the latter. The situation will probably remain unremedied until more effort is made to understand the nature of complex systems and their dependence on human monitors and until the myth that automation of functions eliminates or even diminishes the need for human vigilance is abandoned.

Human Vigilance at the Crossroads

Originally published in Contemporary Psychology: APA Review of Books, 1986, Vol 31(7), 514–515. Reviews the book, Sustained Attention in Human Performance edited by Joel S. Warm (1984). There are 10 chapters in this book, the first and last are an introduction and epilogue, respectively, by the book editor. The editor also covers the psychophysics of vigilance with Jerison. This book provides no clear lead as to the direction these efforts should take. The practical importance of arousal as a whole is seriously underestimated. There should also have been a closer examination of the potential for adding artificial signals to improve vigilance in the field, their beneficial effect has been amply demonstrated in the laboratory. They provide control of some aspects of the task considered critical by the theorists: motivation, conditioned inhibition, and probability matching. (PsycINFO Database Record (c) 2006 APA, all rights reserved)

Dynamic Drilling Displays

Gas and oilwell drilling is a hazardous business which relies on human vigilance to detect a sudden influx of gas from the formation into the well bore, and human control activity to manage the migration of this gas bubble to the surface. The result of human error in either case can result in a blowout which can cause considerable damage to people, equipment and the environment. Human performance in such situations is limited by the harsh physical environment, variable levels of training and variable standards of instrumentation. Recently, computer displays have been introduced to present information in a more appropriate form for aiding human performance. The design of these displays appears to have had very little human factors input. This paper describes some of the ways in which computers displays can be used to reduce the probability of human error and enhance human performance in gas and oilwell drilling.

Effects of ambient illumination over days on human vigilance performance.

Detection rates of 36 college students were measured for three days in an auditory vigilance task under one of three conditions of ambient illumination: dark (less than .33 lx), low (86 lx), and high (170 lx) intensity levels. Within-session performance decrements were seen in all conditions. Increasing the intensity of ambient illumination improved vigilance performance, an effect which became more potent over days. These results are discussed in terms of arousal theory and habituation.

Changes of daytime vigilance in normal humans : M. Okawa, M. Matousek, A.L. Nüth and I. Petersen (Goteborg, Sweden)

Changes of daytime vigilance in normal humans : M. Okawa, M. Matousek, A.L. Nüth and I. Petersen (Goteborg, Sweden)

An Adaptive-Rate Continuous Performance Test: Vigilance Characteristics and Reliability for 400 Male Students

An adaptive-rate Continuous Performance Task for the assessment of human performance has been developed based on the original method of Rosvold, et al. (1956). The stimulus presentation speeds up after correct detections and slows down after errors of omission or commission, allowing applications in a wide range of clinical populations and normal age groups. Adequate error rates are obtained to characterize each individual's performance. Signal detection analysis yields d′ and β parameters with adequate test-retest reliability over 6 mo. A specific decline in a′ over time is consistent with other studies of human vigilance.

A LOW-COST SIMULATOR SYSTEM FOR VIGILANCE RESEARCH

Human detection efficiency performance deteriorates rapidly in a wide variety of monotonous monitoring tasks (Stroh, 1971). The upsurge of interest in research on human performance vigilance began during World War I1 (Baker, 1962). Investigations of human performance decrements were centered about ships' lookouts and radar operators. The interest in vigilance research continues because many of today's military, industrial and transportation systems still embody these features (Adams, 1965; Mackie, 1977). Rapidly developing electronics capability over the past several years has resulted in a dramatic increase in the fidelity of simulated vigilance task apparams with an exponential rise in costs. Beatty, Greenburg, Deibler, and O'HanIon (1974) employed a radar simulator comparable to actual equipment in their study of theta brain wave rhythms and radar monitoring efficiency. While such high fidelity and high'cost apparatus might be justified for large-scale grant-supported projects, there is virtually no research evidence that such fidelity contributes to the validity of experimental outcomes. Finnegan, Kelly, and Trollip ( 1977) noted that the great strides in simulation have often been guided more by what is technologically feasible than by what is economically and practically desirable. Making a system more realistic in appearance does not necessarily make it any better for assessment of human performance factors. The cost of high fidelity equipment has, however, meant that few university psychology departments have been able to support smaller scale vigilance experiments in teaching or research. The system described in this paper was designed to minimize costs and maximize simplicity by employing apparatus commonly available in most psychology or human performance laboratories. It was decided that a minimum system should be capable of providing (1) vigilance task stirn,uli, ( 2 ) variable background clutter, ( 3 ) monotonous conditions, and (4) a permanent recording of stimuli as well as subjects' detection responses.