Acquired Brain Injury

Acquired Brain Injury - Causes, Symptoms, Diagnosis and Treatment

What is acquired brain injury?

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.

What are the different types of ABI?

Brain injury may occur in one of two ways:

  • Closed brain injury
    Closed brain injuries occur when there is a non-penetrating 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.

What is diffuse axonal injury (DAI)?

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 visualize on computed tomography (CT scan) or magnetic resonance imaging (MRI) scans.

What is primary and secondary brain injury?

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.

What causes a head injury?

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), from violence, from falls, or as a result of shaking a child (as seen in cases of child abuse).

What causes bruising and internal damage to the brain?

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.

What are the possible results of brain injury?

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 life-long rehabilitation. Effects of brain injury may include:

Cognitive deficits

  • Coma

  • Confusion

  • 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

Motor deficits

  • Paralysis or weakness

  • Spasticity (tightening and shortening of the muscles)

  • Poor balance

  • Decreased endurance

  • Inability to plan motor movements

  • Delays in initiation

  • Tremors

  • Swallowing problems

  • Poor coordination

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 do 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

Functional deficits

  • Impaired ability with activities of daily living (ADLs) such as dressing, bathing, and eating

  • Problems with organization, shopping, or paying bills

  • Problems with vocational issues

  • Inability to drive a car or operate machinery

Social difficulties

  • Impaired social capacity resulting in difficult interpersonal relationships

  • Difficulties in making and keeping friends

  • Difficulties understanding and responding to the nuances of social interaction

Regulatory disturbances

  • Fatigue

  • Changes in sleep patterns and eating habits

  • Dizziness

  • Headache

  • Loss of bowel and bladder control

Personality or psychiatric changes

  • Apathy

  • Decreased motivation

  • Emotional lability

  • Irritability

  • 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.

Traumatic epilepsy

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.

Can the brain heal after being injured?

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 life-long process of treatment and rehabilitation.

What is coma?

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.

How is coma measured?

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:

Level I

No Response

The patient is in a deep coma and appears soundly asleep; absence of any response to stimuli.

Level II

General Response

The patient responds to pain or repeated stimuli with non-purposeful movements or increased activity.

Level III

Local Response

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.

Level IV

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.

Level V

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.

Level VI

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.

Level VII

Automatic - Appropriate

The patient goes about activities appropriately with minimal confusion, but often appears "robot-like." Judgment, thinking, and problem solving remain impaired.

Level VIII

Purposeful - Appropriate

The patient is oriented with improving memory and skills. May still require supervision due to impaired cognitive ability.

The brain injury rehabilitation program:

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

  • Family support

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:

Patient need:


Self-care skills, including activities of daily living (ADLs)

Feeding, grooming, bathing, dressing, toileting, and sexual functioning

Physical care

Nutritional needs, medications, and skin care

Mobility skills

Walking, transfers, and self-propelling a wheelchair

Communication skills

Speech, writing, and alternative methods of communication

Cognitive skills

Memory, concentration, judgment, problem solving, and organizational skills

Socialization skills

Interacting with others at home and within the community

Vocational training

Work-related skills

Pain management

Medications and alternative methods of managing pain

Psychological testing and counseling

Identifying problems and solutions with thinking, behavioral, and emotional issues

Family support

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:

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 pulmonary rehabilitation team, including any/all of the following:

  • Neurologist/neurosurgeon

  • Physiatrist

  • Internists and specialists

  • Rehabilitation nurse

  • Social worker

  • Physical therapist

  • Occupational therapist

  • Speech/language pathologist

  • Psychologist/neuropsychologist/psychiatrist

  • Recreation therapist

  • Audiologist

  • Dietitian

  • Vocational counselor

  • Orthotist

  • Case manager

  • Respiratory therapist

  • Chaplain

Types of brain injury rehabilitation programs:

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

  • Day-treatment programs

  • Independent living programs