Factors Affecting Reaction Times

Gender- males generally react faster than females

Highly lipophilic compounds like some B-blockers, clonidine and other anti-hypertensives, sedating antihistamines, tricyclic antidepressants, benzodiazepine derivatives along with antipsychotics like quetiapine, olanzapine and haloperidol may adversely effect the CNS and reaction times.

The Odds ratio (OR) for motor vehicle crashes associated with the use of atypical antipsychotics is significant at 2.20 (P < .01).

New sedative users were associated with an increased risk of crash compared to nonusers.
Temazepam hazard ratio (HR) = 1.27 (95% confidence interval [CI] = 0.85, 1.91), trazodone HR = 1.91 (95% CI = 1.62, 2.25), and zolpidem HR = 2.20 (95% CI = 1.64, 2.95). The risk estimates are equivalent to blood alcohol concentration levels between 0.06% and 0.11%.

Drivers consuming Tramadol (adjusted OR 11.41; 95 % CI 1.27, 102.15) were at a significantly increased risk of motor vehicle collision.

Statistically significant associations between drug use and road traffic crashes involvement were found for benzodiazepines and z-hypnotics in 25 out of 28 studies,for cannabis in 23 out of 36 studies, for opioids in 17 out of 25 studies,for antidepressants in 9 out of 13 studies,for amphetamines in 8 out of 10 studies and for cocaine in 5 out of 9 studies.

12.2% of non-HIV infected patients who injected drugs and were followed for an average of 4 years, died from traffic accidents.

Alcohol, cocaine, amphetamines such as speed (amphetamine sulphate) as well as ice (crystal methamphetamine hydrochloride), methiopropamine, methylenedioxymethamphetamine (MDMA, ecstasy) lysergic acid diethylamide (LSD) and heroin

Driving while cannabis-impaired approximately doubles car crash risk and that around one in 10 regular cannabis users develop dependence.

There was a 5 fold increase in the prevalence of THC and alcohol involved in fatal crashes from below 2% in 1991 to just above 10% in 2008.

Synthetic cannabinoids like UR-144 and XLR-11 may also impair driving ability.

Suspended or revoked drivers who continue to drive-which appears to be the majority-are about 3 times more likely to be involved in crashes and to cause a fatal crash.

Drivers had higher risks of crashes following infringement penalties [odds ratio (OR) 1.32; 95% confidence interval (CI) 1.29-1.36], especially crashes when the offender was at fault (1.41; 1.36-1.46). Crash risk relative to a comparable period was very high for teenage drivers (1.55; 1.34-1.78) and among drivers penalized for dangerous driving (3.19; 2.52-4.03) or driving under the influence of alcohol (1.99; 1.67-2.37). The risk remained relatively high for more than 6 months after the penalty, but declined steadily over this period.

612 car drivers, 37.3% (228) reported being involved in a road traffic accident with damage or injury in the past 3 years.Majority in this group were male, older than 65, with no children, not employed and living in an urban area. In the multivariate model, several factors were identified: being widowed (vs. single) (OR = 3.478, CI 95%: 1.159-10.434); living in a suburban area (vs. a rural area) (OR = 5.023, CI 95%: 2.260-11.166); having been checked for alcohol once in the last 3 years (vs. not checked) (OR = 3.124, CI 95%: 2.040-4,783); and seldom drinking an energetic beverage such as coffee when tired (vs. always do it) (OR = 6.822, CI 95%: 2.619-17.769) all suffered a higher risk of being involved in a car accident.

In the psychosocial model of driving behavior (including mistakes ,lapses, and intentional violations) and accidents, psychological factors, depression (P < 0.02), personality trait of conscientiousness (P < 0.02), failure schema due to the parenting style of mother (P = 0.001), and perception of police commands (P < 0.002), all played a significant role in predicting driving behavior. Among social factors, perception of police regulations (P = 0.003), had an important effect on violations and mistakes. Among environmental and behavioral factors, major factors such as drug and alcohol use (P = 0.001,) driving age (P = 0.001), having driver's license (P = 0.013), records of imprisonment or committing a crime (P = 0.012) were also able to predict occurrence of accidents.

Adjusted analysis shows that Guatemalan students had a 4.8 times higher accident rate (CI 95% 3.1-7.4) compared to Spanish students.
This was primarily due to higher mobile usage (74.4 % versus 24.3 %), distraction (47.1 % versus 18.8 %) or not using a seat-belt (23.9% vs 5.9).

Significant age related decrements being markedly visible after 40 years of age but most pronounced in the 70-79 and 80-89 year age groups.
There was a 13 fold increase in crash involvement reported among drivers who were 80 and over.
However marked increase in crash involvement did not start until 75 years of age.
The highest death rates per mile driven, a 13-fold increase, was observed among drivers aged 80 or older, who also had the highest crash death rates.

Drug interactions

Diurnal variation

Impact of active metabolites

Adverse dietary effects of cholesterol reduction

Caffeine and napping may improve performance

Menstrual cycle in females

Braking reaction time was slower after sleep restriction than after normal sleep (mean,1.39 seconds vs. 1.22 seconds; P < 0.01).
Having less than 6 hours sleep in the past 24 hours is associated with a 6 fold increase in motor vehicle crash related injuries

For patients undergoing surgery for lumbar disc herniation, those with a right-side radiculopathy obtained a significant improvement in Driver Reaction Time from 664 ms(preoperative),to 593 ms at 5 weeks after surgery(P<0.05).Those patients with a left-side radiculopathy,improved from 675 ms preoperative to 619 ms.Control subjects had a driving reaction time of 487 ms,which differed significantly from patients at all three testing times(p<0.001).

Reaction times improved after surgery for disc herniation in patients with preoperative paresis. A significant improvement of driver reaction time after surgery was seen in patients with left- and right-sided pareses(p<.005).

Four weeks after minimally invasive primary total hip arthroplasty surgery, patients improved their reaction times by 0.035 s (p = 0.0398) and most patients should be allowed to return to driving.

After 8 days,postoperative total brake response time increased significantly by 30% in right total knee arthroplasty (TKA) and insignificantly by 2% in left TKA. Brake force significantly worsened by 35% in right TKA and by 25% in left TKA during this time.Baseline values were reached at week 12 in right TKA; the impairment of outcome measures, however, was no longer significant at week 6 compared with preoperative values. Total brake response time and brake force in left TKA fell below baseline values at weeks 6 and 12. Brake force in left TKA was the only outcome measure that was significantly impaired 8 days postoperatively.

Use of a cell phone while driving increases the risk of crashing fourfold.
Texting a message increases reaction time by 94.94%, conversation by 13.34% and listening to music while driving by 1.58%

Factors associated with responsibility were distraction induced by an external event (adjusted OR (aOR) = 1.47; 95% confidence interval (CI) [1.06–2.05]), distraction induced by an internal thought (aOR = 2.38; CI: [1.50–3.77]) and attention-deficit/hyperactivity disorder (ADHD), (aOR = 2.18 CI: [1.22–3.88]). The combined effect of ADHD and external distractions was strongly associated with responsibility for the crash (aOR = 5.79 CI: [2.06–16.32]).

Central Field Loss participants reacted more slowly to pedestrians that appeared in the area of visual field loss than in non-scotomatous areas (4.3 vs. 2.4 seconds) and had more late and missed responses than controls (29% vs. 3%)

Advanced glaucoma patients were involved in a significantly higher number of collisions in a driving simulator than the age-matched and driving exposure time-matched normal subjects (119 vs 40, respectively, p<0.0001), particularly in four specific driving simulator scenarios.With these four scenarios, binocular integrated visual field sensitivity was significantly lower in the collision-involved patients than in the collision-uninvolved patients in subfields on or near the track of the simulated hazard (p<0.05). The subfields with the largest area under the receiver operating characteristic (AUROC) curve had values ranging from 0.72 to 0.91 and were located in the paracentral visual field just below the horizontal.

Among male subjects with primary open-angle glaucoma, the prevalence of motor vehicle collisions was significantly higher in the no-restriction group than in the self-restriction group (no-restriction group, 33/107 = 30.8%; self-restriction group, 9/66 = 13.6%, p = 0.01). The crash rate was also significantly higher in the no-restriction group (no-restriction group, 1.4 ± 0.8; self-restriction group, 0.4 ± 0.3, average ± SE, p = 0.01). No restriction was significantly associated with motor vehicle collisions (multivariable-adjusted odds ratios, 2.43 [95% confidence interval, 1.03 to 5.73]). The number of driving self-restrictions was also associated with motor vehicle collisions (multivariable-adjusted odds ratios, 0.41 [95% confidence interval, 0.18 to 0.99], per one increment of self-restriction).

Progression of Parkinson's disease will result in increased driver reaction times.
Patients with reaction times of 0.88 seconds are considered to be unable to drive vehicles safely on the road. However those patients with reaction times of 0.68 seconds are considered to be capable of driving cars safely on the road.

Modafinil significantly improves steering deviation and Psychomotor Vigilance Task reciprocal reaction time over placebo in driving simulators.

Sleep apnoea subjects demonstrated significantly increased steering deviation and crashed more frequently than control subjects in a driving simulator.
Obstructive Sleep apnoea is associated with a higher risk of a motor vehicle accident (risk ratio of 2.45 compared to controls (P<0.001). However CPAP use>4 hours/night was associated with a reduction of motor vehicle accident incidence (7.6 to 2.5 accidents/1,000 drivers/year).

After 3 years of CPAP therapy for obstructive sleep apnoea, motor vehicle accident rate fell to the same rate as the control group.

HIV-infected patients diagnosed with AIDS are on an average 22% slower than uninfected controls.

Docosahexaenoic acid (DHA) supplementation produced significant improvements in complex reaction time (p = 0.004) and complex reaction efficiency (p = 0.003) after 4 weeks treatment in female elite soccer players.

For females the results showed that both red and green had significantly less choice visual choice reaction (P values <0.0001 and 0.0002) when compared with yellow.

Frontotemporal lobar degeneration (FTLD) patients reported difficulty in judging inter-vehicle distances, ignoring road signs and traffic signals, and distraction were reported in 50% (14/28), 61% (17/28), and 50% (14/28) of patients, respectively, and 75% (21/28) patients had caused a traffic accident after dementia onset. The risk of causing an accident was higher in the FTLD group than in the Alzheimer's disease (AD group (odds ratio = 10.4, 95% confidence interval = 3.7-29.1). Furthermore,the mean duration between dementia onset and a traffic accident was 1.35 years in the FTLD group compared with 3.0 years in the AD group (P < 0.01)

Minimal hepatic encephalopathy patients (MHE) showed impaired driving ability that correlated with MHE grade, with impaired vehicle lateral control in spite of reduced driving speed. Patients with MHE also showed psychomotor slowing, longer reaction times, impaired bimanual and visuo-spatial coordination and concentrated attention and slowed speed of anticipation.

Drivers who are categorized as unsafe had made more illegal turns and more crashes on the driving simulator than drivers categorized as safe; a higher proportion of subjects with Minimal hepatic encephalopathy (MHE) were categorized as unsafe drivers at baseline (16%) than subjects without MHE (7%, P=.02), and at 1 year follow up (18% vs 0%, P=.02). Cessation of alcohol within 1 year and illegal turns during simulator navigation tasks were associated with real-life automobile crashes and MHE on in regression analysis; road edge excursions in the simulator were associated with real-life traffic violations.

Hypersomnia patients reported more frequently the occurrence of recent car crashes (in the previous 5 years) than in healthy subjects .This risk that was confirmed in both treated and untreated subjects at study inclusion (Untreated, OR = 2.21 95%CI = [1.30-3.76], Treated OR = 2.04 95%CI = [1.26-3.30]), as well as in all disease categories, and was modulated by subjective sleepiness level (Epworth scale and naps) However, after patients were treated for at least 5 years the risk of car accidents was not different to healthy subjects (OR = 1.23 95%CI = [0.56-2.69]).

The Epworth Sleepiness Scale (OR = 1.13; 95% CI: 1.07-1.23) and suffering from apnea (OR = 4.89; 95% CI: 1.07-23.83) were the best predictors for odds showing increased risk of road accidents.

After a stroke, road sign recognition was better in people who underwent training in a simulator-based driving rehabilitation program compared with control (mean difference 1.69 points on the Road Sign Recognition Task of the Stroke Driver Screening Assessment, 95% CI 0.51 to 2.87, P = 0.007).

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