Acquired brain injury (ABI) occurs when a sudden, external, physical assault damages the brain. It is one of the most common causes of disability and death in adults. ABI is a broad term that describes a vast array of injuries that occur to the brain. The damage can be focal (confined to one area of the brain) or diffuse (occurs in more than one area of the brain). The severity of a brain injury can range from a mild concussion to a severe injury that results in coma or even death. Acquired brain injuries are also commonly referred to as traumatic brain injuries (TBI).
Each year, about 1.4 million people in the U.S. experience a brain injury, and 230,000 are hospitalized and survive. Each year, more than 50,000 people in the U.S. will die following traumatic brain injuries.
Brain injury may occur in one of two ways:
Closed brain injury. Closed brain injuries occur when there is a nonpenetrating injury to the brain with no break in the skull. A closed brain injury is caused by a rapid forward or backward movement and shaking of the brain inside the bony skull that results in bruising and tearing of brain tissue and blood vessels. Closed brain injuries are usually caused by car accidents and falls. Shaking a baby can also result in this type of injury (called shaken baby syndrome).
Penetrating brain injury. Penetrating, or open head injuries occur when there is a break in the skull, such as when a bullet pierces the brain.
Diffuse axonal injury is the shearing (tearing) of the brain's long connecting nerve fibers (axons) that occurs when the brain is injured as it shifts and rotates inside the bony skull. DAI usually causes coma and injury to many different parts of the brain. The changes in the brain are often microscopic and may not be evident on computed tomography (CT scan) or magnetic resonance imaging (MRI) scans.
Primary brain injury refers to the sudden and profound injury to the brain that is considered to be more or less complete at the time of impact. This occurs at the time of the car accident, gunshot wound, or fall.
Secondary brain injury refers to the changes that evolve over a period of time (from hours to days) after the primary brain injury. It includes an entire cascade of cellular, chemical, tissue, or blood vessel changes in the brain that contribute to further destruction of brain tissue.
There are many causes of head injury in children and adults. The most common injuries are from motor vehicle accidents (where the person is either riding in the car or is struck as a pedestrian), violence, falls, or as a result of shaking a child (as seen in cases of child abuse).
When there is a direct blow to the head, the bruising of the brain and the damage to the internal tissue and blood vessels is due to a mechanism called coup-countercoup. A bruise directly related to trauma at the site of impact is called a coup lesion (pronounced COO). As the brain jolts backwards, it can hit the skull on the opposite side and cause a bruise called a countercoup lesion. The jarring of the brain against the sides of the skull can cause shearing (tearing) of the internal lining, tissues, and blood vessels leading to internal bleeding, bruising, or swelling of the brain.
Some brain injuries are mild, with symptoms disappearing over time with proper attention. Others are more severe and may result in permanent disability. The long-term or permanent results of brain injury may require post-injury and possibly lifelong rehabilitation. Effects of brain injury may include:
Shortened attention span
Memory problems and amnesia
Problem solving deficits
Problems with judgment
Inability to understand abstract concepts
Loss of sense of time and space
Decreased awareness of self and others
Inability to accept more than one- or two-step commands simultaneously
Paralysis or weakness
Spasticity (tightening and shortening of the muscles)
Inability to plan motor movements
Delays in initiation
Perceptual or sensory deficits
Changes in hearing, vision, taste, smell, and touch
Loss of sensation or heightened sensation of body parts
Left- or right-sided neglect
Difficulty understanding where limbs are in relation to the body
Vision problems, including double vision, lack of visual acuity, or limited range of vision
Communication and language deficits
Difficulty speaking and understanding speech (aphasia)
Difficulty choosing the right words to say (aphasia)
Difficulty reading (alexia) or writing (agraphia)
Difficulty knowing how to perform certain very common actions, like brushing one's teeth (apraxia)
Slow, hesitant speech and decreased vocabulary
Difficulty forming sentences that make sense
Problems identifying objects and their function
Problems with reading, writing, and ability to work with numbers
Impaired ability with activities of daily living (ADLs), such as dressing, bathing, and eating
Problems with organization, shopping, or paying bills
Inability to drive a car or operate machinery
Impaired social capacity resulting in difficult interpersonal relationships
Difficulties in making and keeping friends
Difficulties understanding and responding to the nuances of social interaction
Changes in sleep patterns and eating habits
Loss of bowel and bladder control
Personality or psychiatric changes
Anxiety and depression
Disinhibition, including temper flare-ups, aggression, cursing, lowered frustration tolerance, and inappropriate sexual behavior
Certain psychiatric disorders are more likely to develop if damage changes the chemical composition of the brain.
Epilepsy can occur with a brain injury, but more commonly with severe or penetrating injuries. While most seizures occur immediately after the injury, or within the first year, it is also possible for epilepsy to surface years later. Epilepsy includes both major or generalized seizures and minor or partial seizures.
Most studies suggest that once brain cells are destroyed or damaged, for the most part, they do not regenerate. However, recovery after brain injury can take place, as, in some cases, other areas of the brain compensate for the injured tissue, or the brain learns to reroute information and function around the damaged areas. The exact amount of recovery is not predictable at the time of injury and may be unknown for months or even years. Each brain injury and rate of recovery is unique. Recovery from a severe brain injury often involves a prolonged or lifelong process of treatment and rehabilitation.
Coma is an altered state of consciousness that may be very deep (unconsciousness) so that no amount of stimulation will cause the patient to respond, or it can be a state of reduced consciousness, so that the patient may move about or respond to pain. Not all patients with brain injury are comatose. The depth of coma, and the time a patient spends in a coma varies greatly depending on the location and severity of the brain injury. Some patients emerge from a coma and have a good recovery; others have significant disabilities.
Depth of the coma is usually measured in the emergency and intensive care settings using a Glascow coma scale. The scale (from 3 to 15) assesses eye opening, verbal response, and motor response. A high score indicates a greater amount of consciousness and awareness.
In rehabilitation settings, another measurement scale is often used to indicate a patient's level of response and ability to function. It is called a Rancho scale and is named for the rehabilitation hospital where it was created, Rancho Los Amigos, in California.
Rancho scales are based on how the patient reacts to external stimuli and the environment. The scales consist of eight different levels and each patient will progress through the levels with starts and stops, progress and plateaus. A brief summary of the components of the Rancho scale include the following:
The patient is in a deep coma and appears soundly asleep; absence of any response to stimuli.
The patient responds to pain or repeated stimuli with nonpurposeful movements or increased activity.
The patient's response is more specific, such as turning the head toward a sound or following a simple command. Responses are delayed and inconsistent.
Confused - Agitated
The patient is in a heightened state of response, confused, agitated, attempts to pull out tubes, bites, hits, or kicks caregivers. Behavior is inappropriate and speech is often incoherent.
Confused - Inappropriate -Not agitated
The patient appears alert and can follow simple commands. Responses are confused and non-purposeful. Memory is impaired and speech is often inappropriate.
Confused - Appropriate
The patient shows purposeful behaviors but requires direction and supervision for activities such as dressing and eating; becoming more aware of the environment; memory improving.
Automatic - Appropriate
The patient goes about activities appropriately with minimal confusion, but often appears "robot-like." Judgment, thinking, and problem solving remain impaired.
Purposeful - Appropriate
The patient is oriented with improving memory and skills. May still require supervision due to impaired cognitive ability.
Rehabilitation of the patient with a brain injury begins during the acute treatment phase. As the patient's condition improves, a more extensive rehabilitation program is often begun. The success of rehabilitation depends on many variables, including the following:
Nature and severity of the brain injury
Type and degree of any resulting impairments and disabilities
Overall health of the patient
It is important to focus on maximizing the patient's capabilities at home and in the community. Positive reinforcement helps recovery by improving self-esteem and promoting independence.
The goal of brain injury rehabilitation is to help the patient return to the highest level of function and independence possible, while improving the overall quality of life--physically, emotionally, and socially.
Areas covered in brain injury rehabilitation programs may include:
Self-care skills, including activities of daily living (ADLs)
Feeding, grooming, bathing, dressing, toileting, and sexual functioning
Nutritional needs, medications, and skin care
Walking, transfers, and self-propelling a wheelchair
Speech, writing, and alternative methods of communication
Memory, concentration, judgment, problem solving, and organizational skills
Interacting with others at home and within the community
Medications and alternative methods of managing pain
Psychological testing and counseling
Identifying problems and solutions with thinking, behavioral, and emotional issues
Assistance with adapting to lifestyle changes, financial concerns, and discharge planning
Patient and family education and training about brain injury, safety issues, home care needs, and adaptive techniques
The brain injury rehabilitation team revolves around the patient and family and helps set short- and long-term treatment goals for recovery. Many skilled professionals are part of the brain injury rehabilitation team, including any or all of the following:
Internists and specialists
There are a variety of brain injury treatment programs, including the following:
Acute rehabilitation programs
Subacute rehabilitation programs
Long-term rehabilitation programs
Transitional living programs
Behavior management programs
Independent living programs