Traumatic brain injury (TBI) happens when a sudden violent event damages the brain. It's a common cause of disability and death in adults. Almost half of TBIs are from falls. Other common causes of TBI are motor vehicle accidents, violence, and sports. The damage may be just in one area of the brain. Or it may be in more parts of the brain. The severity of a brain injury can vary. It may be a mild concussion. Or it may be a severe injury that results in coma or death.

TBI includes a variety of types of injuries to the brain.

A TBI may be either of these:

• Closed brain injury. This is when there is an injury to the brain but no break in the skull. It is caused by a fast forward or backward movement and shaking of the brain inside the hard skull. It can result in bruising or tearing of brain tissue and blood vessels. Closed brain injuries are usually caused by car accidents, falls, and in sports. Brain injury in babies can be caused by a form of child abuse where a baby is shaken hard. It is known as abusive head trauma. It is also called shaken baby syndrome.
• Penetrating brain injury. This injury is when there is a break in the skull. An object such as a sharp tool or a bullet pierces the brain.

And it may be either of these:

• Primary brain injury. This is when injury to the brain is complete at the time of impact. This happens at the time of the motor vehicle accident (MVA), gunshot wound, or fall.
• Secondary brain injury. This is when changes happen hours or days after the primary brain injury. There are a series of tissue changes in the brain. These cause more damage.

The brain has long connected nerve fibers called axons. Diffuse axonal injury is the tearing of these nerve fibers. This can happen when the brain suddenly shifts inside the hard skull. It can cause a minor concussion. Or it can cause a mild to severe coma if many parts of the brain are affected. The changes in the brain are often so small they may not be seen on a CT or MRI scan.

Some brain injuries are mild. Symptoms go away over time with proper care. Others are more severe. These may cause permanent disability. The long-term results of brain injury may need lifelong care. Symptoms of brain injury may include the below.

Most studies suggest that once brain cells are damaged, they don't regrow. But recovery after brain injury can take place. In some cases, other areas of the brain make up for the injured tissue. In other cases, the brain learns to reroute function around the damaged areas. Doctors can't predict the amount of recovery at the time of injury. It may be unknown for months or even years. The rate of recovery varies. It depends on the amount of inflammation and damage. Recovery from a severe brain injury often takes long-term treatment and rehab. (See below.)

Coma is when a person is not awake or aware for a period of time. A person may move around or respond to pain. Or they may not move or respond at all. Not all people with brain injury are in a coma. The type and length of a coma vary a lot. It depends on where and how severe the brain injury is. Some people come out of coma and have a good recovery. Others have problems that cause ongoing issues with daily life.

Rehab after a TBI starts soon after the injury. The success of rehab depends on many things, such as:

• Type of the TBI.
• How severe it is.
• Type of problems the TBI has caused.
• How severe those problems are.
• Overall health.
• Family support.

Rehab helps to improve the person's abilities at home and in the community. The goal of brain injury rehab is to help the person get to the highest level of function and independence. And rehab programs work to help the overall quality of life.

Types of brain injury rehab programs include:

• Acute rehab.
• Subacute rehab.
• Long-term rehab.
• Transitional living.
• Behavior management.
• Day-treatment.
• Independent living.

The brain injury rehab team helps the injured person and their family. They help set goals for recovery. The team may include any of these:

• Neurologist/neurosurgeon
• Physiatrist
• Internists and specialists
• Rehabilitation nurse
• Social worker
• Physical therapist
• Occupational therapist
• Speech-language therapist
• Psychologist/neuropsychologist/psychiatrist
• Recreation therapist
• Audiologist
• Dietitian
• Vocational counselor
• Orthotist
• Case manager
• Respiratory therapist
• Chaplain