PubMed Health⌕ Search

Biomedical subjects

J Törnros

Publications and source records attributed to J Törnros.

11 recordsLinked to original sources
PubMed1998

Driving behavior in a real and a simulated road tunnel--a validation study.

The aim was to validate driving behaviour in a simulated road tunnel. Speed and lateral position of 20 subjects were measured in a real tunnel and in the same tunnel implemented in the VTI driving simulator. In both situations a left-hand steered and manually geared passenger car was used. Driving speed was higher in the simulated tunnel than in the real tunnel. Elimination of speed information from the speedometer caused a similar small speed increase in both situations. Also, the difference in speed between driving lanes was similar in both cases. The effects on speed variation were similar to that for speed level. Regarding lateral position, subjects positioned the car somewhat further away from the nearest tunnel wall in the real tunnel than in the simulated tunnel. In both situations the distance to the nearest wall was greater when it was located to the left of the driver than on the opposite side. Lateral position deviation was about the same when the road was straight, but in a curved section it was somewhat greater for the simulated tunnel. It is concluded that behavioural validity in absolute terms was not quite satisfactory, especially regarding choice of speed, whereas relative validity was good for both speed and lateral position.

Adult↗
PubMed1997

[The Stockholm project: drunken drivers are given supervision instead of prison sentences].

There is a need to compile a national database on drunken driving, since experience from other countries is not necessarily applicable to Swedish conditions. Legislation, drinking habits, and public attitudes to drinking and driving differ markedly from country to country. Since 1990, the driving licence unit of the Magnus Huss Clinic has been collaborating with a probation office unit of the National Prisons and Probation Administration and the Offender Aid Society on a non-institutional drunk driving program of at least one year's duration, often linked with several years' follow-up. The article outlines experience and results derived from this program. Among other things, blood alcohol content is questioned as an indicator of the severity of a drinking problem.

Adult↗
PubMed1995

Long-term effect of uvulopalatopharyngoplasty on driving performance.

OBJECTIVE: It has been questioned whether the effect of uvulopalatopharyngoplasty lasts as years go by. From a previous study it is known that patients with severe rhonchopathy, complaining of sleepiness at the wheel, improve their vigilance and driving performance immediately following uvulopalatopharyngoplasty, but is this effect persisting? DESIGN: In a cohort study, the long-term effect of surgical treatment on driving vigilance was evaluated on 13 middle-aged (median, 52 years) male patients and five matched controls. Three to 4 years postoperatively, they were subjected to a boring 90-minute-long retest in an advanced driving simulator and daytime polysomnography, identical to those performed preoperatively. Factors measured were brake reaction time, lateral position deviation, and off-road incidents. The patients were also asked to assess their driving skills on a self-report and their vigilance on a visual analogue scale. RESULTS: All but one patient reported themselves as being more vigilant and safe drivers following surgery. Objective results showed that the initial improvement in brake reaction time, lateral position deviation, and number of off-road incidents was sustained, but not always in concordance with the apnea index. CONCLUSION: The positive effect of uvulopalatopharyngoplasty on vigilance and driving performance remains after 4 years. This may have a substantial impact on traffic safety.

Accidents, Traffic↗
PubMed1995

Effect of driving speed on reaction time during motorway driving.

Effects of driving speed (70, 90 and 110 km/h) on subsidiary auditory reaction time were studied during car driving on a motorway with a speed limit of 110 km/h. Driving distance was held constant at about 200 km. Twenty-four subjects participated in a repeated-measurement design. Reaction time was found to be slower at 70 km/h than at 110 km/h. Before and after the driving session, the subjects' simple reaction time, mood, and alertness were measured in the laboratory. No significant differential after-effects of driving speed were found on any of these measures, although subjects rated themselves as less energetic towards the end of their journey when driving at the former compared to the latter speed.

Adult↗
PubMed1991

Effects on driving performance of visual field defects: a driving simulator study.

To elucidate the possible traffic safety risks induced by visual field defects, a method was developed based on a driving simulator. The capacity to detect stimuli of different sizes appearing in 24 different positions on the screen in front of the driver was measured. Two groups of normal subjects and a number of subjects with different visual field defects were studied. In the groups of normals, the median reaction times were fairly homogenous. There was a slight difference between central and peripheral stimuli, which was somewhat larger for the older subjects. Among the subjects with field defects, the individual variations were very dominant. Very few of these showed a capacity to compensate for their deficiency. In order to gain insight into possible compensatory mechanisms of these persons, eye movement recordings were made. The results indicate that the visual search pattern may be of importance in this respect. Some comparisons with respect to detection capacity were also made with one-eyed subjects and with optically generated field restrictions (spectacles and spectacle frames).

Adult↗
PubMed1991

Simulated long-term driving performance before and after uvulopalatopharyngoplasty.

To investigate whether automobile drivers with the clinical features of sleep apnea syndrome (SAS) perform worse than controls in a simulated long-term test drive, and to see if their driving improves after uvulopalatopharyngoplasty (UPPP), 15 male drivers with SAS, suffering from sleep spells whilst driving, and 10 matched controls without a history of SAS or hypersomnia at the wheel were tested in an advanced driving simulator. Brake reaction time, lateral position deviation and off-road episodes were measured during a 90-min rural drive at twilight conditions. The clinical evaluation was made by a questionnaire scoring symptoms of snoring, sleep disturbances and diurnal sleepiness before and after surgery. Before UPPP the patient group showed impaired performance in all three effect measures compared to controls. UPPP resulted in improved reaction time performance (average mean improvement: 0.5 s, average 90th percentile improvement 0.8 s). Furthermore, 12 of the 15 patients reported a marked improvement regarding sleepiness whilst driving. For these clinically successful cases the number of off-road episodes decreased substantially. We conclude that most patients improve their long-term driving performance as a result of UPPP.

Accidents, Traffic↗
PubMed1991

Acute and hang-over effects of alcohol on simulated driving performance.

The aim was to study hang-over effects from alcohol in simulated driving. The driving task was to negotiate 20 km in as short time as possible. The road had many curves, horizontal and vertical, with ice friction at irregular intervals. 24 healthy volunteers, aged 22-46, with valid driving licenses, all screened as moderate drinkers, participated as subjects in a repeated measurements design. In the acute intoxicated state (average BAC 150 mg%), driving performance was severely impaired. Performance was also impaired, but to a much lesser degree, in the morning after the alcohol consumption when average BAC was just below 40 mg%. Later during the day no significant differences were demonstrated. After another night's sleep, all effects were gone. An issue raised in a previous study on hang-over effects, whether the subjects were treated exactly alike in the hang-over and the control conditions the night before testing (with the exception for the alcohol consumption in the first case), that is attended a party and stayed overnight at the research institute in both conditions, or whether they did so only in the hang-over condition, did not seem to matter for the estimated hang-over effect.

Adult↗
PubMed1990

Acute and carry-over effects of brotizolam compared to nitrazepam and placebo in monotonous simulated driving.

Eighteen healthy volunteers of both sexes, aged 20-35 years, were tested in the morning after three nights of medication with brotizolam 0.25 mg, nitrazepam 5 mg or placebo on a monotonous simulated driving task. The effect measures were subsidiary auditory reaction time and time outside road. Measurements of self-rated alertness were carried out as well. No effects were demonstrated from treatments on either measure. Nitrazepam however tended to score worst on all measures, except time outside road which could not be analysed with respect to statistical significance because of an insufficient number of subjects leaving the road. Twelve of the subjects were also tested immediately after drug intake on the first night of each medication period. Reaction time decrement was observed in both active drugs conditions with no difference between the two. The other measures, however non-significant, pointed in the same direction with the greatest decrement for nitrazepam.

Adult↗
PubMed1986

The carry-over effects of triazolam compared with nitrazepam and placebo in acute emergency driving situations and in monotonous simulated driving.

Eighteen healthy volunteers of both sexes, aged 20-34, were tested in the morning while undertaking real car driving avoidance manoeuvres and during monotonous simulated driving after 1 and 3 nights of medication with triazolam 0.25 mg, nitrazepam 5 mg or placebo. The study was a double-blind, randomized, cross-over study, where a minimum of 7 days wash-out separated the 3 treatment periods. Nitrazepam was found to impair performance in the simulated task after 1 but not after 3 nights of medication. Performance in the triazolam condition was not significantly different from the other conditions on this task on either day. However, after one night of medication triazolam tended to score worse than placebo but better than nitrazepam. In real car driving a tendency was noted for nitrazepam to score worst, whereas the difference between placebo and triazolam was hardly noticeable. The same tendency appeared on both days.

Automobile Driving↗
PubMedDate not supplied

Driving vigilance simulator test.

Drivers suffering from sleepiness at the wheel run the risk of being involved in car accidents. To evaluate whether objective data of driving performance can be assessed in patients with excessive tendency of falling asleep at the wheel, two test versions of a computerized driving program were created to fit an advanced driving simulator. For the evaluation 15 male drivers with habitual sleep spells whilst driving were selected among patients with the clinical features of the sleep apnoea syndrome. The brake reaction time and the deviations from straight road-line were significantly increased when compared to the performance of 10 matched controls. Irrespective of test version, the driving simulator with the program used was found to be a sensitive method to ascertain driving vigilance impairment in quantitative terms. It would also be a valuable method to evaluate the efficiency of treatment in selected patients.

Accidents, Traffic↗