Closed-head injury

If symptoms of a head injury are seen after an accident, medical care is necessary to diagnose and treat the injury. Without medical attention, injuries can progress and cause further brain damage, disability, or death.[5]

Closed-head injuries are caused primarily by vehicular accidents, falls, acts of violence, and sports injuries.[4] Falls account for 35.2% of brain injuries in the United States, with rates highest for children ages 0–4 years and adults ages 75 years and older.[3] Head injuries are more common in men than women across every age group.[3] Boys aged 0–4 years have the highest rates of brain injury related hospital visits, hospitalizations, and deaths combined.[3] Multiple mild traumatic brain injuries sustained over a short period of time (hours to weeks), often seen with sports-related injuries, can result in major neurological or cognitive deficits or fatality.[9]

Blast-related traumatic brain injuries are often closed-head injuries and result from rapid changes in atmospheric pressure, objects dislodged by the blast hitting people, or people being thrown into motion by the blast [10] Blast-related injuries have shown a recent increase in occurrence with the return of veterans from Iraq such that traumatic brain injury has been coined the "signature injury" of Operation Iraqi Freedom [11]

Closed-head injuries can range from mild injuries to debilitating traumatic brain injuries and can lead to severe brain damage or death. Common closed-head injuries include:[5]

• concussion – a head injury resulting in temporary dysfunction of normal brain function. Almost half of the total concussions reported each year are sports-related [5]
• intracranial hematoma – a condition in which a blood vessel ruptures causing a pool of blood to form around the brain (subdural hematoma) or between the brain and the skull (epidural hematoma). Intracranial hematoma causes an increase in pressure on the brain and requires immediate medical attention.[5]
• cerebral contusion – a bruise to the brain tissue as a result of trauma. Contusions are local in nature, separating them from concussions.[5]
• diffuse axonal injury – These injuries are frequently seen in car accidents and cause permanent damage to the brain. Severe diffuse axonal injuries often lead to comas or vegetative states.[5]

There are several different types of treatment available to those who have suffered a closed-head injury. The treatment type chosen can depend on several factors including the type and severity of injury as well as the effects that injury has on the patient.[15] The course of treatment differs for each patient and can include several types of treatment, depending on the patient's specific needs. Early treatment is vital to recovering lost motor function after an injury, but cognitive abilities can be recovered regardless of time past since injury.[16]

Many closed-head injuries can be prevented by proper use of safety equipment during dangerous activities. Common safety features that can reduce the likelihood of experiencing a brain injury include helmets, hard hats, car seats, and safety belts. Another safety precaution that can decrease a person's risk for brain injury is not to drink and drive or allow oneself to be driven by a person who has been drinking or who is otherwise impaired.[19]

Helmets can be used to decrease closed-head injuries acquired during athletic activities, and are considered necessary for sports such as American "tackle" football, where frequent head impacts are a normal part of the game. However, recent studies have questioned the effectiveness of even American football helmets, where the assumed protection of helmets promotes far more head impacts, a behavior known as risk compensation. The net result seems to have been an increase, not decrease, in injuries.[20] The similar sports of Australian-rules football and rugby are always played helmetless, and see far fewer traumatic brain injuries. (See Australian rules football injuries.)

Bicycle helmets are perhaps the most promoted variety of helmet, based on the assumption that cycling without a helmet is a dangerous activity, with a large risk of serious brain injury. However, available data clearly shows that to be false. Cycling (with approximately 700 American fatalities per year from all medical causes) is a very minor source of fatal traumatic brain injury, whose American total is approximately 52,000 per year.[21] Similarly, bicycling causes only 3% of America's non-fatal traumatic brain injury.

Still, bicycle-helmet promotion campaigns are common, and many U.S jurisdictions have enacted mandatory bicycle-helmet laws for children. A few such jurisdictions, a few Canadian provinces, plus Australia and New Zealand mandate bicycle helmets even for adults. A bicycle-helmet educational campaign directed toward children claimed an increase in helmet use from 5.5% to 40.2% leading to a claimed decrease in bicycle-related head injuries by nearly 67%.[22] However, other sources have shown that bicycle-helmet promotion reduces cycling, often with no per-cyclist reduction in traumatic brain injury.[23][24]

Estimates of bicycle-helmet use by American adults vary. One study found that only 25-30% of American adults wear helmets while riding bicycles,[25] despite decades of promotion and despite sport cyclists' adoption of helmets as part of their uniform.

Following the commercial (as opposed to public-health) success of bicycle helmets, there have been successful attempts to promote the sale of ski helmets. Again, results have been less than impressive, with great increases in helmet use yielding no reduction in fatalities, and with most injury reduction confined to lacerations, contusions, and minor concussions, as opposed to more serious head injuries.[26]

There have been rare campaigns for motoring helmets.[27] Unfortunately, just as people greatly overestimate the traumatic brain injury danger of bicycling, they greatly underestimate the risk of motoring, which remains the largest source of traumatic brain injury in the developed world, despite the protective effects of seatbelts and airbags.

• Cerebral contusion
• Concussion
• Diffuse axonal injury
• Intracranial hemorrhage
• Traumatic brain injury