Following head trauma, there is often good reason to counsel patients about driving. Not surprisingly, the array of cognitive deficits that may be present can increase the risk of injury to the brain injury survivor as well as passengers, pedestrians and other drivers.
In our very mobile society, following injury there will inevitably be both internal as well as external pressure to resume driving along with all other normal activities of daily living. In particular, patients who are otherwise capable of returning to work or school might find that full reintegration can be frustrated by the inability to resume driving.
Notwithstanding the patient’s urge to resume a “normal” existence, it is important to be mindful of the hazards presented by driving with an injured brain. Traumatic brain injury is not an event where the injury is fixed at the time of the initial trauma. Brain injury can be broken down into primary and secondary injury. The former occurs at the time of the traumatic event, and the latter unfolds over days, weeks and months following the trauma. This is due to the neuro-metabolic cascade created by the release of enzymes and chemicals, including glutamate, that alter the cellular energy demand and place the injured brain in a metabolic crisis. The New Neurometabolic Cascade of Concussion, Giza CC et al, Neurosurgery 75:S24–S33, 2014.
The cascade of changes within the concussed brain can produce an evolving array of cognitive changes including diminished processing speed, visual-spatial limitations, impaired attention and executive dysfunction. These deficits can “significantly impact” the ability to operate a motor vehicle safely. The Effects of Driver Distraction for Individuals With Traumatic Brain Injuries, Neyens DM et al, Human Factors, Vol. 57, No. 8, December 2015, pp. 1472–1488. These categories of cognitive impairment present self-evident safety risks based upon the diminished capacity to perceive and identify conditions while driving, as well as the ability to quickly process and act decisively to those conditions. These limitations can translate into the following problems: 1) inability to see and identify conditions; 2) inability to maintain a constant position in a lane; 3) inability to maintain concentration during varying periods of time; 4) difficulty recalling directions; 5) difficulty with hand-eye coordination; and 6) problem solving.
Before getting behind the wheel following a traumatic brain injury, it is important to obtain proper clearance and to resume slowly. There are facilities where a patient’s capacity can be tested using driving simulation. Another option would be to secure an evaluation with a certified driving instructor. It is important to recognize that following a traumatic brain injury –including even a mild concussion, driving with one or more physical or cognitive impairments could cause another injury to you or someone else.
By Stewart M. Casper. Posted November 11, 2015
