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Biomedical subjects

K A Brookhuis

Publications and source records attributed to K A Brookhuis.

15 recordsLinked to original sources
PubMed2003

Criteria for driver impairment.

Most traffic accidents can be attributed to driver impairment, e.g. inattention, fatigue, intoxication, etc. It is now technically feasible to monitor and diagnose driver behaviour with respect to impairment with the aid of a limited number of in-vehicle sensors. However, a valid framework for the evaluation of driver impairment is still lacking. To provide an acceptable definition of driver impairment, a method to assess absolute and relative criteria was proposed to fulfil the paradoxical goal of defining impaired driving which is consistent yet adaptable to interindividual differences.

Accidents, Traffic↗
PubMed2003

Dissociable effects of a single dose of ecstasy (MDMA) on psychomotor skills and attentional performance.

Ecstasy (3,4-methylenedioxymethamphetamine, MDMA) is a psychoactive recreational drug widely used by young people visiting dance parties, and has been associated with poor cognitive function. The current study assessed the influence of a single dose of MDMA 75 mg and alcohol 0.5 g/kg on cognition, psychomotor performance and driving-related task performance. Twelve healthy recreational ecstasy users participated in an experimental study conducted according to a double-blind, double-dummy, placebo-controlled three-way cross-over design. MDMA improved psychomotor performance, such as movement speed and tracking performance in a single task, as well as in a divided attention task. MDMA impaired the ability to predict object movement under divided attention. However, the inability to accurately predict object movement after MDMA may indicate impairment of particular performance skills relevant to driving. There was no effect of MDMA on visual search, planning or retrieval from semantic memory.

Adult↗
PubMed2000

A comparison of different ways to approximate time-to-line crossing (TLC) during car driving.

Three experiments are presented in which the accuracy of different methods to approximate time-to-line crossing is assessed the first experiment TLC was computed, using a trigonometric method, during normal driving while the vehicle stayed in lane. The minima of TLC were compared with two approximations and it was found computing TLC as lateral distance divided by lateral velocity gave poor results. It was concluded that this simple approximation is not suitable for measuring TLC minima in studies of driver behaviour. A way of computing TLC that takes account of the curved path of the vehicle resulted in a good fit of TLC minima. In two other experiments the vehicle exceeded the lane boundary, either intentionally as a result of a lane change manoeuvre, or unintentionally as a result of impaired driving. In these cases no TLC minima exists since these only occur as a result of correcting steering actions to stay within the lane. In contrast to normal lane keeping, it was found that prior to crossing the lane boundary, the simple approximation resulted in more accurate estimation of available time before the lane boundary is exceeded compared to the more complex approximation. This indicates that for lane keeping support systems and systems that detect when the driver has fallen asleep and drifts out of lane, a simple algorithm for TLC estimation may give reliable results, while this algorithm is not accurate enough for more fundamental studies of driver behaviour. However, the reliability of the approximation is only satisfactory over a very short time range before the lane boundary is actual exceeded. This may result in warnings that come too late and result in too little time to respond for the driver.

Accidents, Traffic↗
PubMed1999

Elderly and young driver's reaction to an in-car enforcement and tutoring system.

A system that contrasts driver behaviour with normative behaviour was tested in an advanced driving simulator. Drivers were provided with auditory and visual tutoring messages if deviations were detected from normative, i.e. legally allowed behaviour with respect to a selection of offences. Results showed that the system was very effective in increasing law-abiding behaviour, which has a major positive effect on traffic safety. However, driver mental effort, as indicated by self-reports and drivers' physiological states, was slightly increased in conditions where drivers received feedback. Opinion about the tutoring system was positive in terms of usefulness. Self-reports on satisfaction differed between age groups; young drivers rated it low, while elderly drivers held a positive attitude.

Accidents, Traffic↗
PubMed1995

Effect of road layout and road environment on driving performance, drivers' physiology and road appreciation.

Infrastructural changes were implemented on rural 80 km/h roads in The Netherlands in an effort to reduce speeding. The road infrastructure changes were designed to produce discomfort for the speeding driver by providing noxious auditory and haptic feedback. On experimental roads, smooth-surface road width was reduced by using blocks of gravel chippings placed along the centre line and at intervals on road edges. It was predicted that these changes would increase mental load while driving, and thereby decrease speeding. In a field experiment 28 subjects drove an instrumented vehicle over experimental and control roads. A decrease in driving speed and swerving behaviour was found on the experimental roads, and this was coupled with a decrease in heart rate variability, consistent with an increase in mental load. Roads in two different road-side environments (woodland vs. moorland) were also tested. There were differences in driver appraisal of the two environments, but no interactions were observed between these appraisals and driving performance on the experimental roads. It is concluded that the infrastructural measures have a useful role to play in road safety through a reduction in driver speeding.

Acceleration↗
PubMed1994

Training young cyclists to cope with dynamic traffic situations.

Two training methods were developed to teach young cyclists (8/9 years) how to behave in priority situations. One method was developed along the lines of the modelling principle. In earlier studies it was shown that this method is effective in teaching crossing strategies to young pedestrians. The other training method was based upon Anderson's Adaptive Control of Thought (ACT) theory, which describes the development of cognitive skills by proceduralisation and composition of behaviour and knowledge elements into automatic behaviour sequences. Two groups of children were trained with one of these methods. A control group did not receive traffic-related training in that period. The effect of the training was assessed by a knowledge test and a behaviour test. The results showed that the partly theoretical ACT approach initially resulted in an increased level of knowledge, which was found to have disappeared after a month. The modelling approach did not affect the level of knowledge. Both approaches had an equally positive effect on simple behavioural strategies, such as signalling and visual search behaviour. Correct application of priority rules appeared to be very difficult to teach. There was no effect of the two training methods. It seemed that children apply informal rules rather than formal rules when dealing with other traffic. It is hypothesized that these informal rules should form the starting point for training activities, because formal rules do not fit into children's cognitive framework of schemes, and therefore cannot be stored and retrieved effectively.

Accidents, Traffic↗
PubMed1993

The use of psychophysiology to assess driver status.

Twenty subjects completed an on-the-road driving experiment, consisting of two different tests conducted on two separate days. A two-part test was administered while subjects were under the influence of alcohol (BAC < = 0.05%); a four-part test was administered without alcohol consisting of a 2.5 h driving test under vigilance conditions on a quiet highway. The order of the tests was balanced across subjects. Changes in relevant physiological parameters, such as ECG and EEG, reflected changes in driver status and predicted driving impairment. Impairment of driving performance was measured in a standard driving test (SD lateral position and SD steering wheel movements) and in a recently developed car-following test (reaction to speed changes of a leading car).

Adult↗
PubMed1993

Acute and subchronic effects of the H1-histamine receptor antagonist ebastine in 10, 20 and 30 mg dose, and triprolidine 10 mg on car driving performance.

1. The effects of a new antihistamine, ebastine (10, 20 and 30 mg), on several parameters of driving performance in actual traffic were studied in 15 healthy male volunteers. Subjects were treated for 5 days, and their driving performance tested on day 1 and day 5. The study was double-blind, placebo controlled and included the antihistamine triprolidine (10 mg sustained release) as an active drug control. 2. General tolerability was good except in one case following the reference compound triprolidine. No significant changes in driving performance were found with the new antihistamine ebastine at any dosage, on day 1 or day 5. Triprolidine (10 mg) significantly increased both the amount of weaving and the delay in following speed manoeuvres of a leading car, compared with placebo. 3. The results suggest that ebastine in doses up to 30 mg may be relatively safe for use by those who drive motor vehicles while under medication. The results do not warrant such a conclusion for triprolidine 10 mg.

Adult↗
PubMed1991

Assessing driver status: a demonstration experiment on the road.

Twenty subjects completed an on-the-road experiment that consisted of two parts on two separate days. One was a one-hour driving test under the influence of alcohol (BAC less than = 0.05%), the second a two-and-a-half-hour driving test under vigilance conditions. Impairment of driving performance was measured in a car-following test as well as in a standard driving test. Changes in relevant physiological parameters, such as ECG and EEG, reflected changes in driver status and predicted driving performance impairment.

Adult↗
PubMed1991

The effects of mobile telephoning on driving performance.

The effects of telephoning while driving were studied in three different traffic conditions, i.e. in light traffic on a quiet motorway, in heavy traffic on a four-lane ring-road, and in city traffic. Twelve subjects, unfamiliar with mobile telephones, drove an instrumented vehicle for one hour each day during three weeks and while in each of the three traffic conditions, had to operate the mobile telephone for a short while. To ensure a fixed "heavy traffic load" in the second condition, the subjects were instructed to follow another instrumented vehicle (at a safe distance). The results showed a significant effect of telephoning while driving as opposed to normal driving (i.e., not involving telephone conversation), on the effort subjectively measured by an effort scale and objectively measured by heartrate indices and on some of the measured parameters of driving performance. One half of the subjects had to operate the telephone manually, the other half performed the telephone task with a handsfree mobile telephone set. The subjects who operated the handsfree telephone showed better control over the test vehicle than the subjects who operated the handheld telephone, as measured by the steering wheel movements. Also, a clear improvement over time in the course of the 15 test days was found for some of the measurements. As a consequence of the results, some advice concerning mobile telephoning can be given to authorities, manufacturers, and users.

Adult↗
PubMed1990

Repeated dose effects of lormetazepam and flurazepam upon driving performance.

The residual effects of lormetazepam 1 mg and 2 mg in soft gelatine capsules on driving performance were assessed and compared to those of flurazepam 30 mg, which is also a powerful hypnotic, but possesses a far less favourable pharmacokinetic profile with a long-acting sedative metabolite. Driving performance was tested 10 to 11 h and 16 to 17 h post administration, after 2 days on placebo (baseline), and 2, 4 and 7 days of drug treatment (active), and after 1 and 3 days following the resumption of placebo (washout). The driving test consisted of operating an instrumented motor-vehicle over a 72 km highway circuit in light traffic. Flurazepam 30 mg significantly impaired the ability to control the lateral position of the vehicle compared to placebo baseline measurements. The degree of impairment was substantial in the female subjects and was greater in the morning than in the afternoon. Lormetazepam 1 mg showed no residual effect on driving performance. Lormetazepam 2 mg impaired driving performance to some extent on the following morning, 10 to 11 h post administration, but no residual effect was found in the afternoon. All drugs improved sleep quality and prolonged sleep duration to more or less the same extent.

Adult↗
PubMed1983

The P3 complex as an index of information processing: the effects of response probability.

The amplitude and latency of the late positive (P3b) component of the cortical evoked potential were studied in a visual search task. The main independent variables were memory load, response type and relative response frequency. In the experiment we used the varied mapping procedure, a condition in which the target and distractor stimuli were thoroughly mixed across trials. The main goal of the study was to establish the locus of relative response frequency. In many models of choice reaction time the effect of this task variable is believed to occur in the response selection stage. If the latency of the P3b only indexes stimulus evaluation, independent of response selection and organization processes, relative response frequency should only affect reaction time and not the latency of P3b. The results indicated that the latency of P3b was very sensitive to the number of comparisons, response type and relative response frequency. In addition, only a subset of subjects selectively prepared for the most probable response. Only these subjects showed the effects of relative response frequency in their reaction times too. Response preparation, however, did not affect the latency of P3b. It was concluded that the latency of P3b is a very sensitive index of the search and comparison process, the binary decision process, and the probability of the type of the decision, but insensitive to motor preparation.

Adult↗
PubMed1981

Late positive components and stimulus evaluation time.

The amplitude and latency of late positive components were, together with reaction time (RT), studied in a task which combines visual and memory search. The visual display contained either one, two or four letters, as did the memory set. Six load combinations, resulting in one, four, eight and 16 comparisons, were examined. The reaction time data indicated a self-terminating search process. Three late positive components were present in the evoked potential: one at 375 msec after the onset of the display, one at 375 msec after the offset of the display and one around 600 msec. Only the latter component appeared to be sensitive to the number of comparisons. Adaptive averaging was applied to this latter component. The latency of this P300 suggested, in contrast to the RT data, an exhaustive search process. In addition there was a negligible correlation between the response latency and P300 latency at single trial level. Several hypotheses are suggested for what P300 could have to tell us.

Adult↗