Head Trauma And Driving

Important new developments have occurred since my previous post on July 29, 2015.

Currently there are at least 80 different diseases that possess statistically significant driver impairment with P<0.05 and many of them have substantially lower P values. (1)

Furthermore there are many other diseases that will also show statistically significant driver impairment once the sample size of the study population is increased.

Head trauma with driver impairment characterised by confusion, dizziness and drowsiness possesses the highest odds ratio among the various disease groups for driver impairment. (Odds Ratio {OR}, 36.00.Confidence Interval (11.09, 116.90).

This is followed by Lactic Acidosis {OR}, 15.00 (1.75, 128.40) Neurotic Disorder {OR} 12.00 (1.34, 107.37) and Delirium, Acute 10.50 (2.18, 50.55) (2)

Wherever possible, if any of these patients require drug therapy for any reason they should be prescribed a minimally sedating drug that does not impair driving abilities.

Child Head Injuries in China

A total number of 47 690 cases with child head injuries were examined by the  Chinese National Injury Surveillance System (NISS) in 2014. (3)

These included 32,542 males and 15,148 females.

Around 43.4% of them were aged under 1-4 years old.

The 3 leading causes responsible for child head injuries were falls (69.57%), hit by blunt force (14.23%) or road traffic (11.01%).

Main areas responsible for the head injuries to happen were: at home (44.98%), at public places (19.65%) or on roads/streets (15.81%).

Recreation activates (77.88%), driving (7.32%), sports (5.72%) were the 3 major activities causing the injuries to take place.

Majority of the circumstances were unintentional (95.35%), with bruising (71.69%) or mild injuries (85.27%) and children went home after treatment (90.25%).

In a much larger study by J Yang and colleagues they reviewed 133,172 cases of head injuries that accounted for 26.2% of all the injury cases. (4)

They found that the incidence among males was 2.1 times higher than females.

Furthermore the top 5 leading causes of head injuries were falls 24.6% (32 796/133 172), blunt force injuries 24.4% (32 446/133 172), motor car accident injuries 20.3% (26 993/133 172), knife or sharp force injuries 10.7% (14 183/133 172) and non-motor car accident injuries 6.7% (8 919/133 172).

Main areas where head injuries occurred include: roads/streets 32.5% (43 262/133 172), working places 22.2% (29 526/133 172), at home 20.5% (27 925/133 172) and public residences 10.8% (14 367/133 172).

Interestingly, recreational activities 37.9% (50 479/133 172), driving 26.1% (34 749/133 172), paid jobs 24.8% (33 034/133 172) were the 3 major activities associated with head injuries.

Severity of injuries would depend on the circumstances on site.

For minor injuries, bruise accounted for 63.5% (67 929/106 912). Brain trauma 21.5% (5 119/23 803) and fracture 14.9% (3 554/23 803) seemed an increasing trend. 

However, severe injuries would include brain trauma 74.6% (1 833/2 457) and 78.8% (104 940/133 172) of the patients with head injuries would go home after receiving treatment at the hospital.

Fatalities only occurred in 0.1% (134/133 172) of cases.

The authors concluded that head injury appeared the highest proportion among all the body injuries that required special attention.

Comparison of medical history and injury severity of disease-related versus trauma-related bicyclist fatalities

M Hitosugi and co-investigators wished to clarify the relationship between injury severity and mechanism of death in bicycle fatalities resulting from trauma and compare them with those resulting from disease, with a view of finding effective measures to prevent fatal bicyclist accidents. (5)

Accident and autopsy records were examined for bicyclist fatalities who had undergone forensic autopsy at the Dokkyo Medical University School of Medicine between the period September 1999 and March 2014.

These authors reviewed victims' health histories, causes of death, blood alcohol levels mechanisms of injury, Abbreviated Injury Scale (AIS) scores and Injury Severity Scores (ISSs) were determined.

55 bicyclists (43 male and 12 female) with a mean age of 62.5±17.3 years were included in this study.

16 victims had driven under the influence of alcohol (mean blood concentration of 1.8±0.7 mg/ml).

Mean Injury Severity Scores (ISS) was 32.4 and the chest had the highest mean Abbreviated Injury Scale (AIS) score (2.6), followed by the head (2.1) and the neck (1.8).

39 victims (70.9%) had died of trauma and 16 had died of disease.

The disease-death victims had significantly higher incidence of having hypertension, diabetes mellitus, hyperlipidemia, heart disease or cerebrovascular diseases (50.0% vs. 22.2%, p=0.03) with a lower rate of drunk driving (6.3% vs. 41.0%, p=0.01) than the trauma-death group.

Interestingly all victims who were affected by disease, and 33.3% of trauma-death victims, had collapsed on the road without a vehicle collision (p<0.001).

The mean ISS of the trauma-death group was significantly greater than that of the disease-death group (44.0 vs. 4.2, p<0.001).

Except for facial wounds, the AIS scores were significantly higher in trauma-death victims than in the disease-death group (p<0.005).

The author’s advice to effectively reduce bicyclist fatalities, was to strongly advocate efforts that will increase compliance with drunk driving prohibitions.

They also recommended that for victims of fatal bicycle accidents with a medical history of diseases, a forensic autopsy should be performed to establish a disease-related death while bicycle riding.

We are obliged to put into effect preventative safety measures that will take into consideration the physical condition of bicyclists, to reduce the incidence of these types of accidents.

What is the prevalence and effective factors of crash helmet usage among motorcyclists in Iran?

Crash helmets are important to protect the head during crashes and reduces the rate of severe injuries and fatalities.

Even though it has been proved that wearing the crash helmet may save the deriver's life by around 42%; previous studies revealed that the rate of wearing crash helmet has not been acceptable in Iran.

Because of the very large number of motorcyclists on the roads in Iran, the use of crash helmet is a very important area of research.

S T Hedari and fellow investigators evaluated the use of crash helmets by the motorcyclists. (6)

They conducted an observational study on 414 motorcyclists in Shiraz, Southern Iran.

All participants completed a questioner containing demographic features, motor cycle license, crash helmet use, and the reasons for using motorcycles.

They observed that all the participants were males who were aged from 16 to 64 years with mean age 27±9.28.

The results of logistic regression model revealed that only the drivers who had motorcycle license (OR=2.73, C.I: 1.40-7.24), employed the motorcycle for reasons other than pleasure (OR=3.18, C.I: 1.42-7.37) and been driving for 10 or more years (OR=1.92 95% C.I: 1.12-3.30) had greater rate of wearing crash helmet.

However, age, educational levels, and other demographical variables did not play a significant role in the rate of crash helmet usage.

These authors believe that in order to improve the rate of crash helmet use, it is necessary to enact obligatory requirement for driving license by motorcyclists and to increase the legal age for motorcycle driving.

Self-Awareness and Self-Ratings of On-Road Driving Performance After Traumatic Brain Injury

J R Gooden and colleagues wanted to examine self-rated, clinician-rated, and self-awareness of on-road driving performance in individuals with traumatic brain injury (TBI) deemed fit and unfit to resume driving and healthy controls. (7)

Furthermore, they wished to explore their associations with demographic, injury, cognitive, and mood variables.

These authors studied 37 individuals with moderate to severe Traumatic Brain Injury (TBI), and 49 healthy age, sex, and education-matched controls from Australia and Canada.

All participants completed an on-road assessment, the Brain Injury Driving Self-Awareness Measure (BIDSAM), and a comprehensive neuropsychological assessment.

Awareness scores on the BIDSAM were significantly different between groups, F(2, 83) = 28.44 (P < .001; η = 0.41), with post hoc tests indicating TBI participants who failed the on-road assessment had poorer scores compared with those who passed and controls.

Poor self-awareness was significantly correlated with reduced psychomotor speed (rs = -0.37; P < .01) and attentional switching (rs = 0.28; P < .01).

Furthermore, worse self-ratings of driving were associated with depression (rs = 0.42; P < .01) and anxiety (rs = 0.38; P < .01).

Interestingly, those individuals with TBI who failed an on-road assessment significantly overrated their driving ability.

Impaired cognitive function was associated with reduced self-awareness of driving.

These results suggest that impaired awareness of driving may need to be addressed as part of driver rehabilitation programs.

Predictors of the On-Road Driving Assessment After Traumatic Brain Injury: Comparing Cognitive Tests, Injury Factors, and Demographics.

Very recently A McKay and fellow researchers undertook to examine the relationship between performance on cognitive tests and on-road driving assessment in a sample of persons with traumatic brain injury (TBI).(8)

They also wished to compare cognitive predictors of the on-road assessment with demographic and injury-related predictors.

They studied 99 people with mild-severe TBI who completed an on-road driving assessment in an Australian rehabilitation setting.

This was a designed as an examination of retrospective case series.

They utilised the Wechsler Test of Adult Reading or National Adult Reading Test-Revised; 4 subtests from the Wechsler Adult Intelligence Scale-III; Rey Auditory Verbal Leaning Test; Rey Complex Figure Test; Trail Making Test; demographic factors (age, sex, years licensed); and injury-related factors (duration of posttraumatic amnesia; time post injury).

RESULTS

Participants who were unsuccessful in the driving assessment did poorer on measures of visual memory, attention, and executive processing; however, cognitive tests were weak correlates (r values <0.3) and poor predictors of the driving assessment.

Posttraumatic amnesia duration mediated by time post injury was the strongest predictor of the driving assessment-that is, participants with more severe TBIs had later driving assessments and were more likely to fail.

These authors concluded that cognitive tests are not reliable predictors of the on-road driving assessment outcome.

Moreover, traumatic brain injury severity may be a better predictor of on-road driving; however, additional research is required to identify the best predictors of driving behaviour after TBI.

Driving after concussion: Is it safe to drive after symptoms resolve?

J D Schmidt and co-workers wished to compare driving performance between individuals with and without a concussion and to explore relationships between neuropsychological and driving performance. (9)

14 participants with concussion (Age: 20. 2±0.9yo) and 14 non-concussed age and driving experience matched controls (Age: 20. 4±1.1yo) finalized a graded symptom checklist, a brief neuropsychological exam, and a 20.5km driving simulation task.

Participants with a concussion completed driving simulation within 48 hours of becoming asymptomatic (15.9±9.0 days post-concussion).

One-way ANOVAs was performed to compare total number of crashes, lane excursions, tickets; as well as standard deviation of lateral position (SDLP), and standard deviation of speed.

Furthermore, Pearson's correlations were conducted to examine the relationship between the neuropsychological and driving performance separately by group (α=0.05).

Participants with a concussion committed more frequent lane excursions (concussed: 10.9±4.5; controls: 7.4±2.4; p=0.017) and exhibited greater SDLP compared to controls during the first (concussed: 45.7±21.3cm, controls:27.4±6.1cm; p=0.030) and final curve (concussed:39.6±24.4cm; controls:33.5±21.3cm; p=0.036). Poorer performance on symbol digit modalities (r=-0.54), Rey Osterrieth Complex Figure (r=-0.53), verbal memory (r=-0.77), and motor speed (r=-0.54) were correlated with more frequent lane excursions among the concussed group, but not the control group.

Despite being asymptomatic, concussed subjects exhibited poorer vehicle control, especially when navigating curves. 

Driving impairments may continue beyond when individuals with a concussion have returned to driving.

Their research provides preliminary guidance regarding which neuropsychological functions may best reflect driving impairment following concussion.

What About Post-Concussion Syndrome?

KM Barlow has reviewed the Post-concussion syndrome and established that it is a symptom complex with a wide range of somatic, cognitive, sleep, and affective features, and is the most common consequence of traumatic brain injury. (10)

Moreover, between 14% and 29% of children with mild traumatic brain injury will continue to have post-concussion symptoms at 3 months, but the pathophysiological mechanisms driving this is poorly understood.

The relative contribution of trauma factors to post-concussion syndrome decreases over time and, instead, premorbid factors become important forecasters of symptom persistence by 3 to 6 months post-injury.

Differential diagnoses includes headache disorder, anxiety, cervical injury, depression, somatization, vestibular dysfunction, and visual dysfunction.

While the long-term outcome for most children is good, there is significant morbidity in the short term.

Management approaches target problematic symptoms such as sleep and mood disturbances, headaches and cognitive complaints.

The acute respiratory distress syndrome following isolated severe traumatic brain injury

Acute respiratory distress syndrome (ARDS) is frequent after traumatic brain injury (TBI) and is associated with poorer neurologic outcomes and longer hospitalization.

However, the incidence and associated causes of ARDS in isolated TBI have not been thoroughly investigated.

Consequently CM Hendrickson evaluated a subgroup analysis of 210 consecutive patients with isolated severe TBI enrolled in a prospective observational cohort at a Level 1 trauma centre between 2005 and 2014. (11)

Patients required endotracheal intubation and had isolated severe TBI defined by a head Abbreviated Injury Scale (AIS) score of 3 or greater and AIS score lower than 3 in all other categories.

ARDS within the first 8 days of admission was thoroughly examined using Berlin criteria.

Regression analyses were used to test the relationship between predictors of interest and ARDS.

The occurrence of ARDS in the first 8 days after severe isolated TBI was 30%. Patients who developed ARDS were administered more crystalloids (4.3 L vs. 3.5 L, p = 0.005) and blood products in the first 12 hours of admission.

 Patients with ARDS had significantly poorer clinical outcomes measured at 28 days, including longer median intensive care unit and hospital stays (4 days vs. 13 days, p < 0.001, and 7.5 days vs. 14.5 days, p < 0.001, respectively).

In unadjusted logistic regression analyses, the odds of developing ARDS were significantly associated with head AIS score (odds ratio [OR], 1.8; p = 0.018), male sex (OR, 2.9; p = 0.012), and early transfusion of platelets (OR, 2.8; p = 0.003). These associations were alike in a multivariate logistic regression model.

In the era of balanced haemostatic resuscitation practices, severity of head injury, male sex, early crystalloids, and early transfusion of platelets are associated with a higher risk of ARDS after severe isolated TBI.

Furthermore, early transfusion of platelets after severe TBI may be a modifiable risk factor for ARDS, and these results invite further study into causal mechanisms driving this observed association.   

Community Reintegration Difficulties Among Veterans and Active Duty Service Members With Traumatic Brain Injury

S McGarity and fellow investigators examined community reintegration problems among Veterans and military service members with mild or moderate/severe traumatic brain injury (TBI) at 1 year post-injury. (12)

Furthermore they wished to recognize unique predictors that may contribute to these difficulties

154 Participants at VA Polytrauma Rehabilitation Centres who were inpatients were registered in the VA TBI Model Systems Program with available injury severity data (mild = 28.6%; moderate/severe = 71.4%) and 1-year post-injury outcome data.

This was a prospective longitudinal cohort study

Community reintegration outcomes included employability, independent driving, and general community participation.

Additional measures assessed posttraumatic stress, depression, and cognitive and motor functioning.

These authors found that in the mild TBI (mTBI) group, posttraumatic stress disorder and depressive symptoms were associated with lower levels of various community reintegration outcomes.

Moreover, in the moderate/severe TBI group, cognition and motor skills were significantly linked with lower levels of community participation, independent driving, and employability.

Community reintegration is problematic for Veterans and active duty service members with a history of TBI.

Unique comorbidities across injury severity groups constrain full reintegration into the community.

These results highlight the ongoing rehabilitation needs of persons with TBI, specifically evidence-based mental healthcare, in all-encompassing comprehensive rehabilitation programs consistent with a chronic disease management.

Conclusion

There are many varied considerations that need to be reviewed regarding when it is safe for a person to drive a motor vehicle after a head injury.

Concomitant illnesses or use of sedating drugs that may adversely impact a person’s ability to drive a vehicle safely must always be a major consideration as is the risk of an adverse drug interaction for patients on multiple medications.

Furthermore drivers who are over 60 years of age already possess impaired brake reaction times due to aging. (13)

We must always be vigilant to take into account all of the above factors when selecting the most appropriate drug for a particular patients illness.

Wherever possible, minimally sedating drugs should be selected so that we can reduce the 1.2 million annual deaths that occur from road traffic accidents.

References

1)   Leroy A, Morse MM.APPENDIX VIII. Table 2B Significant Odds Ratios for Driver Impairing Diseases.US Department of Transportation/National Highway Traffic Safety Administration. Exploratory study of the relationship between multiple medications and vehicle crashes: analysis of databases. Washington, DC: U.S.DOT/NHTSA; 2008: Publication DTNH22-02-C-05075. P217-220, May, 2008.

2)   Leroy A, Morse MM.Table 12: Top 15 Disease groups with Highest Odds Ratios (p< .05).US Department of Transportation/National Highway Traffic Safety Administration. Exploratory study of the relationship between multiple medications and vehicle crashes: analysis of databases. Washington, DC: U.S.DOT/NHTSA; 2008: Publication DTNH22-02-C-05075. P48, May, 2008

3)   Ji C, Duan L, Er Y, Ye P, Wang Y, Deng X, Gao X, Jin Y, Wang L. Study on child head-injuries through data derived from the National Injury Surveillance System of China, 2014.Zhonghua Liu Xing Bing Xue Za Zhi. 2016 Apr; 37(4):527-30. doi: 10.3760/cma.j.issn.0254-6450.2016.04.017.

4)   Yang J, Du W, Zhou J, Zhang Y, Shi Z, Qiu J, Wu M. Characteristics of head injuries-data from the Jiangsu Injury Surveillance System, 2006-2014. Zhonghua Liu Xing Bing Xue Za Zhi. 2016 Apr; 37(4):522-6. doi: 10.3760/cma.j.issn.0254-6450.2016.04.016.

5)   Hitosugi M, Koseki T, Miyama G, Furukawa S, Morita S. Comparison of the injury severity and medical history of disease-related versus trauma-related bicyclist fatalities. Leg Med (Tokyo). 2016 Jan; 18:58-61. doi: 10.1016/j.legalmed.2015.12.001. Epub 2015 Dec 12.

6)   Heydari ST, Lankarani KB, Vossoughi M, Javanmardi K, Sarikhani Y, Mahjoor K, Mahmoodi M, Khabaz Shirazi M, Akbari M. The prevalence and effective factors of crash helmet usage among motorcyclists in Iran. J Inj Violence Res. 2016 Jan; 8(1):1-5. doi: 10.5249/jivr.v8i1.667. Epub 2015 Sep 10.

7)   Gooden JR, Ponsford JL, Charlton JL, Ross PE, Marshall S, Gagnon S, Bédard M, Stolwyk RJ . Self-Awareness and Self-Ratings of On-Road Driving Performance After Traumatic Brain Injury. J Head Trauma Rehabil. 2016 Jan 29. [Epub ahead of print]

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8)   McKay A, Liew C, Sch?nberger M, Ross P, Ponsford J. Predictors of the On-Road Driving Assessment After Traumatic Brain Injury: Comparing Cognitive Tests, Injury Factors, and Demographics. J Head Trauma Rehabil. 2016 Nov/Dec; 31(6):E44-E52.

9)   Schmidt JD, Hoffman NL, Ranchet M, Miller LS, Tomporowski PD, Akinwuntan AE, Devos H. Driving after concussion: Is it safe to drive after symptoms resolve? J Neurotrauma. 2016 Dec 13. [Epub ahead of print]

10) Barlow KM. Postconcussion Syndrome: A Review. J Child Neurol. 2016 Jan; 31(1):57-67. doi: 10.1177/0883073814543305. Epub 2014 Oct 20.

11) Hendrickson CM, Howard BM, Kornblith LZ, Conroy AS, Nelson MF, Zhuo H, Liu KD, Manley GT, Matthay MA, Calfee CS, Cohen MJ. The acute respiratory distress syndrome following isolated severe traumatic brain injury. J Trauma Acute Care Surg. 2016 Jun; 80(6):989-97. doi: 10.1097/TA.0000000000000982.

12) McGarity S, Barnett SD, Lamberty G, Kretzmer T, Powell-Cope G, Patel N, Nakase-Richardson R. Community Reintegration Problems Among Veterans and Active Duty Service Members With Traumatic Brain Injury. J Head Trauma Rehabil. 2016 Jun 17. [Epub ahead of print]

13) Doroudgar S, Chuang HM, Perry PJ, Thomas K, Bohnert K, Canedo J. Driving Performance Comparing Older versus Younger Drivers. Traffic Inj Prev. 2016 Jun 21:0. [Epub ahead of print]