Types of Brain Injuries
The brain can receive several different types of injuries depending on the type of force and amount of force that impacts the head. The type of injury the brain receives may effect just one functional area of the brain, various areas, or all areas of the brain. Types of traumatic brain injuries and their characteristics are discussed below, followed by related definitions.
A more descriptive term than “head injury”. Damage to the brain that results in impairments in physical, cognitive, speech/language and behavioral functioning. The damage may be caused by an external physical force, insufficient blood supply, toxic substance, malignancy, disease-producing organisms, congenital disorders, birth trauma or degenerative processes.
A concussion is caused when the brain receives trauma from an impact or a sudden momentum or movement change. The blood vessels in the brain may stretch and cranial nerves may be damaged.
- A concussion can be caused by direct blows to the head, gunshot wounds, violent shaking of the head, or force from a whiplash type injury.
- Both closed and open head injuries can produce a concussion. A concussion is the most common type of traumatic brain injury.
- A person may or may not experience a brief loss of consciousness (not exceeding 20 minutes). A person may remain conscious, but feel “dazed” or “punch drunk”.
- A concussion may or may not show up on a diagnostic imaging test, such as a CAT Scan.
- Skull fracture, brain bleeding, or swelling may or may not be present. Therefore, concussion is sometimes defined by exclusion and is considered a complex neurobehavioral syndrome.
- A concussion can cause diffuse axonal type injury resulting in permanent or temporary damage.
- A blood clot in the brain can occur occasionally and be fatal.
- It may take a few months to a few years for a concussion to heal.
A contusion is a bruise (bleeding) on the brain.
- A contusion can be the result of a direct impact to the head.
- Large contusions may need to be surgically removed.
Coup-Contrecoup Injury describes contusions that are both at the site of the impact and on the complete opposite side of the brain.
- This occurs when the force impacting the head is not only great enough to cause a contusion at the site of impact, but also is able to move the brain and cause it to slam into the opposite side of the skull, which causes the additional contusion.
Diffuse Axonal Injury
A Diffuse Axonal Injury can be caused by shaking or strong rotation of the head, as with Shaken Baby Syndrome, or by rotational forces, such as with a car accident.
- Injury occurs because the unmoving brain lags behind the movement of the skull, causing brain structures to tear.
- There is extensive tearing of nerve tissue throughout the brain. This can cause brain chemicals to be released, causing additional injury.
- The tearing of the nerve tissue disrupts the brain’s regular communication and chemical processes.
- This disturbance in the brain can produce temporary or permanent widespread brain damage, coma, or death.
- A person with a diffuse axonal injury could present a variety of functional impairments depending on where the shearing (tears) occurred in the brain.
Source: Brain Injury Source Volume 4 Issue
Traumatic Brain Injury
Damage to living brain tissue by an external mechanical forces or motion. It is usually characterized by a period of altered consciousness (amnesia or coma) that can be very brief (minutes) or very long (months/indefinitely). The term does not include brain injuries that are caused by insufficient blood supply, toxic substances, malignancy, disease-producing organisms, congenital disorders, birth trauma or degenerative processes.
- Closed Brain Injury: Occurs when the head accelerates and then rapidly decelerates or collides with another object (for example, the windshield of a car) and brain tissue is damaged, not by the presence of a foreign object within the brain, but by the violent smashing, shaking, stretching and twisting of brain tissue. The nerve endings connecting the skull to the brain are often torn or become completely separated from the brain. Closed brain injuries typically cause diffuse tissue damage that result in disabilities, which are generalized and highly variable.
- Open (Penetrating) Brain Injury: Occurs when an object (e.g. bullet, knife) fractures the skull, enters the brain and injures the brain tissue in the process. These injuries tend to damage localized areas of the brain and result in discrete and relatively predictable disabilities.
- Acquired Brain Injury (ABI): The implication of this term is that the individual experienced normal growth and development from conception through birth until sustaining an insult to the brain later that resulted in impairment of brain function. ABI is caused by the shearing of brain nerve fiber due to trauma or by cell death related to swelling, bleeding, disease or loss of oxygen to the brain (anoxia). Whether mild, moderate or severe, acquired brain injury can cause physical, cognitive, speech/language and behavioral dysfunction.
Near drowning, electrical shock, drug overdose, kidney/heart failure, industrial/chemical exposure, injury subsequent to TBI/CVA.
Acquired Brain Disorder (ABD)
Acquired brain disorder is a broader category, which includes neurological disorders as well as acquired brain injury. They may each result in trauma or disruption to the brain and nervous system from a variety of sources.
The brain is the control board for all functions of the body. It is comprised of the cortex, which controls most thinking functions, the cerebellum, which coordinates movement, and the brain stem, which controls consciousness, alertness and basic functions such as breathing, respiration and pulse. The brain function can be disrupted in a number of ways: injuries, toxins, illness and unrelated medical conditions. These disorders to the brain and nervous system include, in addition to acquired brain injuries, neurological brain disorders such as multiple sclerosis, Huntington’s Disease, Parkinson’s Disease and other rare neurological disorders.
Second Impact Syndrome “Recurrent Traumatic Brain Injury”
Second Impact Syndrome, also termed “recurrent traumatic brain injury,” can occur when a person sustains a second traumatic brain injury before the symptoms of the first traumatic brain injury have healed. The second injury may occur from days to weeks following the first. Loss of consciousness is not required. The second impact is more likely to cause brain swelling and widespread damage.
- Because death can occur rapidly, emergency medical treatment is needed as soon as possible.
- The long-term effects of recurrent brain injury can be muscle spasms, increased muscle tone, rapidly changing emotions, hallucinations, and difficulty thinking and learning.
Shaken Baby Syndrome
Shaken Baby Syndrome is a violent criminal act that causes traumatic brain injury. Shaken Baby Syndrome occurs when the perpetrator aggressively shakes a baby or young child. The forceful whiplash-like motion causes the brain to be injured.
- Blood vessels between the brain and skull rupture and bleed.
- The accumulation of blood causes the brain tissue to compress while the injury causes the brain to swell. This damages the brain cells.
- Shaken Baby Syndrome can cause seizures, lifelong disability, coma, and death.
- Irritability, changes in eating patterns, tiredness, difficulty breathing, dilated pupils, seizures, and vomiting are signs of Shaken Baby Syndrome. A baby experiencing such symptoms needs immediate emergency medical attention.
(The Shaken Baby Alliance. [Online August 22, 2002: http://www.shakenbaby.com])
Locked in Syndrome
Locked in Syndrome is a rare neurological condition in which a person cannot physically move any part of the body except the eyes.
- The person is conscious and able to think.
- Vertical eye movements and eye blinking can be used to communicate with others and operate environmental controls.
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