Traumatic brain injury (TBI) affects tens of millions of people worldwide each year with about 5 million deaths. For those who survive there is often permanent neurological impairment. TBI is therefore a serious public health issue that needs to be addressed. The largest international study of TBI was recently published in Nature Medicine, providing some insight into how best to approach the issue.
For background, TBI is exactly what it sounds like – traumatic injury to the brain. This is mostly from external forces to the head, rather than something happening inside the skull, resulting from either something hitting the head or the head hitting something. The brain is a soft jelly-like organ essentially floating in cerebrospinal fluid inside the skull. When such an injury occurs the brain impacts the inside of the skull on the side of the injury, but then can whip back and hit the other side as well (so-called coup contrecoup injury). This can cause surface bruising on the brain.
Perhaps worse, however, is the shearing forces on the entire brain, which as you might imagine is a delicate structure. These forces can cause diffuse axonal injury – a tearing of the axonal connections within the brain. This can result in widespread disruption of the brain’s connections with itself, impairing brain function.
Typical symptoms of TBI include headaches, impaired memory, impaired concentration, persistent dizziness, and difficulty processing sensory information. Patients often feel overwhelmed by everyday situations, like being in a room with multiple people, riding in a car with rapidly moving scenery, or having to keep track of daily activity.
Management of TBI focuses on speeding recovery, avoiding anything that might exacerbate it, and treating symptoms. One important intervention is called neurological rest – avoiding any activity or environment that causes stress or worsens symptoms. There are some neurorehabilitation techniques, and some medications may be helpful. What we do not have is any curative intervention – there is currently no way to reverse the diffuse axonal injury, other than the brain’s own healing ability. This means that symptoms are often permanent.
Getting to the recent study – they looked at over 2,000 TBI patients from 100 hospitals in 29 countries. The most common cause of TBI was automobile accidents, especially in countries with low human developmental index (HDI) tier. In the highest HDI tier ground level falls were more common. This may partly be artifactual as people are less likely to even make it to a hospital (where the data was gathered) in low HDI countries.
The overwhelming conclusion of the study was that the most effective public health measure in order to limit the morbidity and mortality of TBI is to prevent the injuries in the first place. This in turn means that we need to find ways to reduce head injuries from traffic accidents, and we need to prevent falls in the elderly. Second, we need to improve the healthcare infrastructure available so that people with TBI get treated quickly and effectively.
How do we prevent TBIs from traffic accidents? First – wear a helmet, if you are riding a bike, motorcycle, or scooter. Helmets reduce the force on the skull, reducing the risk of TBI by 65-88%. They also reduce the severity of the TBI if one occurs. In a car, wear your seat belt, and place children in appropriate car seats. Air bags are also very effective, and in the US most new cars have not only the front air bags but the side curtain air bags to protect the head.
Preventing ground-level falls in the elderly is also a critical public health measure. This can be as simple as using a cane, which unfortunately many people resist. This can progress to a walker or even scooter when necessary. A home safety evaluation is also useful – removing any tripping hazards, for example. This often falls to family members as often people who are at risk of falling do not recognize the risk or may be resistant to intervention.
The study highlights that simple common-sense interventions are often the most effective public health interventions we have at our disposal. For TBI, prevention is the best approach, as there is unlikely to be any effective restorative treatment anytime soon.
