OVERVIEW: Table of Contents- To go directly to a section, click on a topic below.

• The Brain
• Traumatic Brain Injury
• Facts and Stats
• Who sustains brain injuries?
• Costs
• Morbidity and Mortality
• Causes
• Consequences
• Prevention
• Frequency of TBI/SCI in Maryland

The Brain

The brain is a vital part of the central nervous system and serves as the control center for all of the body's functions including conscious activities such as walking and talking, and unconscious ones such as breathing, heart rate, etc. The brain controls thought, comprehension, speech and emotion. Injury to the brain--whether the result of severe head trauma such as a gunshot wound or a skull fracture, or a closed head injury in which there is no fracture or penetration of the skull - can disrupt some or all of these functions.

Enclosed within the skull, the brain is a gelatinous material that floats within a protective sea of cerebrospinal fluid. This fluid supports the brain and acts as a shock absorber in rapid head movements. Both the brain and the cerebrospinal fluid are protected to some degree within the bony framework of the skull. The outer surface of the skull is smooth, but the inner surface is rough and jagged and can cause significant damage in closed head injuries. In such injuries, the head and body in motion are abruptly stopped, causing the brain to rebound within the skull and move over these rough bony structures.

There are three main areas of the brain: 1. the cortex (cerebrum), 2. the cerebellum, and 3. the brain stem (diencephalon). The cortex is the largest of the three and is the center where most thinking functions occur. It is divided into four lobes, each of which controls particular functions and skills. Additionally, the cortex is divided into two hemispheres: the right and the left. The left hemisphere is usually the dominant of the two and controls verbal functions such as speaking, writing, reading, and calculating. The right hemisphere usually controls more visual-spatial functions such as visual memory, copying, drawing, and rhythm. The cerebellum controls coordination, balance and posture.

The brain stem acts as a relay station between incoming sensations and the cortex, which processes and interprets those sensations. The brain stem connects the two hemispheres of the brain to the spinal cord and is also the point of origin for 12 cranial nerves. When incoming stimuli travel through the brain stem and are received by the cortex, a response is generated and then relayed back through the brain stem to the body. Because of its vital role as a relay station and its function in controlling consciousness, alertness and basic bodily functions, the brain stem is perhaps the most critical area in terms of damage to the brain.

Traumatic brain injury can have serious and lifelong effects on the physical and mental functioning of the survivor. Loss of consciousness, permanently altered memory and/or personality, partial or complete paralysis, and persistent vegetative state are just some of the devastating possibilities brain injury survivors and their families face.

Traumatic Brain Injury

The term "brain injury" refers to any injury of the brain and can be caused by fracture or penetration of the skull (such as in the case of a vehicle accident, fall or gunshot wound), a disease process (neurotoxins, infections, tumors, metabolic abnormalities, etc.) or a closed head injury such as in the case of rapid acceleration or deceleration of the head, including Shaken Baby Syndrome. These injuries can have devastating lifelong effects on physical and mental functioning.

Depending on the location and severity of the injury, the body can be affected in a myriad of ways. When the injury results from head trauma, damage to the brain may occur at the time of impact or may develop later due to swelling (cerebral edema) and bleeding into the brain (intracerebral hemorrhage) or bleeding around the brain (epidural or subdural hemorrhage). When the head is hit with sufficient force, the brain turns and twists on its axis (the brain stem), interrupting normal nerve pathways and causing a loss of consciousness. If this unconsciousness persists over a long period of time, the injured person is considered to be in a coma, a condition caused by the disruption of the nerve fibers going from the brain stem to the cortex.

If the injury is severe, as in the case of an acceleration-deceleration injury in which the moving head impacts against a hard, fixed surface, multiple areas of the brain are damaged. For example, a compression fracture occurs in the area where the head impacted the fixed surface. Upon impact, the brain rebounds forward and backward against the skull (this is called coup-contracoup), which tears the subdural veins, causes damage to the temporal lobes as they move across the rough bony structures within the skull, and results in bleeding, swelling of the brain stem, and shearing of the blood vessels and nerve fibers.

The term "closed head injury" is used when the brain has been damaged without penetration of the skull by another object. One example of this is Shaken Baby Syndrome, in which the brain is damaged by severe and violent shaking or twisting. Such injury often occurs without leaving obvious external signs. The difference between closed and penetrating injuries can be profound. In a bullet wound to the head, for example, a large area of the brain may be destroyed but the resulting neurologic deficit may be minor if that area was not a critical one. In contrast, closed head injuries result in more widespread damage and can result in more extensive neurologic deficits. These deficits can include partial to complete paralysis, cognitive, behavioral, and memory dysfunction, persistent vegetative state, and death. These last two are the most feared outcomes in cases of brain injury, however advances in trauma care have led to decreased rates for both in recent years.

Beyond the obvious physical effects of brain injury, survivors frequently cope with depression, anxiety, loss of self esteem, altered personality, and in some cases, a lack of self-awareness by the injury survivor of any existing deficits.

Some Facts About Traumatic Brain Injury

• A conservative estimate puts the total number of traumatic brain injuries (TBI) at over two million per year, with 500,000 severe enough to require hospitalization.

• Every 15 seconds someone sustains a brain injury in the U.S.; every five minutes, one of those people will die and another will become permanently disabled.

• TBI is a leading cause of death and disability in children and young adults.

• Each year 75,000 to 100,000 Americans will die as a result of a TBI. Most deaths occur at the time of injury or within the first two hours of hospitalization.

• Of those who survive their initial injury, approximately 70,000 to 90,000 will endure lifelong debilitating loss of function. An additional 2,000 will exist in a persistent vegetative state.

• Young men between the ages of 14 and 24 have the highest rate of injury. Males are more likely to suffer serious brain injuries than are females.

Who Sustains Brain Injuries?

The risk of TBI among men is more than twice that of women. The ratio of male to female incidence is approximately 2.5 to 1. Mortality ratios are approximately 3.5 to 1 (Kraus 1995; Kraus and McArthur 1995). This is probably due to gender differences in risk-taking activities and exposure to occupational hazards. Populations at highest risk include males aged 14 to 24 years, followed by infants and children, then the elderly (Kraus 1993: 10). Over 50% of TBI injuries occur among this population age range.

Ethnic and socio-economic origin are significant risk factors in the occurrence of TBI. The Afro-American population has a higher rate of TBI than other ethnic groups in the United States. Most of these incidents are related to homicide. The TBI risk pattern of economically-disadvantaged groups is significantly higher in comparison to high-income populations (Kraus 1993:11).

Another significant risk factor in the incidence of brain injury is the occurrence of a previous brain injury. After a TBI incident, the potential risk for subsequent multiple injuries is extremely common. Among people with an initial TBI incident, the risk of a second injury is three times that of the general population, and after a second brain injury, the potential risk for a third one increases to eight times that of the normal average (Solomon and Sparadeo 1992).

Children are at a particular risk of bicycle-related injuries and deaths. Most brain injuries occur during the summer months (i.e. May, June and July) (Mazurek 1994). 76% of TBIs occur among children less than 15 years of age. Boys are more likely than girls to sustain a brain injury.

Costs Of Traumatic Brain Injury

• A survivor of a severe brain injury typically faces 5 to 10 years of intensive services with an estimated lifetime cost of $4 million.

• The economic cost of TBI in the United States approaches $25 billion per year.
  

Source:

Head Injury Task Force Reports, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 1990.

Morbidity and Mortality

(Disclaimer: The exact percentage of TBI mortality and morbidity is unknown. It is, however, estimated based on epidemiological studies using different statistical methodologies and approaches. Because methodologies differ in defining and identifying significant cases of TBI mortality and morbidity, statistical data on this issue may vary.)

Worldwide TBI mortality rates range from about 15 to 30 per 100,000 population annually. Based on current census reports, it is estimated that TBI claims approximately 1,165,000 lives per year (Kraus 1995). Of the five to ten percent of deaths related to general injuries, approximately 40% is associated with traumatic brain injury (Kraus 1995).

In the United States, it is estimated that 300,000 people were admitted to the hospital with a TBI in 1992. 5 to 10% of the number of people hospitalized with an injury die from TBI (Kraus 1995). Among the hospitalized survivors, one in five will suffer significant long-term disability (Kraus 1995).

TBI results in long-term disabilities for more than 75,000 people each year (Committee on Trauma Research, National Research Council. Injury in America: A Continuing Public Health Problem. Washington, D.C.: National Academy Press, 1985.)

The Centers for Disease Control and Prevention estimates that TBI claims more than 50,000 lives each year. At this rate, American deaths from TBI since 1977 exceed the total of war dead from all US wars, including the Civil War. In the meantime, 70,000 to 90,000 people have moderate to acute brain injuries that result in disabling conditions which may last a lifetime. (NAGHSR NEWS).

More than half of all TBI deaths occur at the scene of the injurious event. Half of all fatalities among TBI occur within 10 minutes of the incident (Kraus 1995).

Causes Of Traumatic Brain Injury

• Motor vehicle crashes account for 50% of all fatal and non-fatal TBIs. This includes all crashes involving cars, trucks, motorcycles, bicycles, and pedestrians. The majority of fatal brain injuries are due to motor vehicle crashes (43%) and firearms (34%) followed by falls (9%).

• Between 32 and 73% of all brain injuries resulting in hospitalization are accompanied by a high blood alcohol level. Fatality crashes involving men are much more likely to be alcohol related than those involving women (The Insurance Institute for Highway Safety 1994). One study found a positive history of alcohol abuse or dependence prior to injury in 58% of TBI survivors. Heavy drinkers are much more likely to be intoxicated at the time of injury (57%) than those without a history of heavy drinking (31%) (Solomon and Sparadeo 1992).

• Among the elderly, falls are second only to motor vehicle crashes as the leading cause of TBI (Heath 1994).

• Child abuse accounts for 64% of traumatic brain injuries in infants.

• Each year in the United States, 50,000 children sustain bicycle related brain injuries. Over 400 of these children die as a result of their injuries.

Consequences Of Traumatic Brain Injury

• PHYSICAL: Impairment of speech, vision and hearing loss, headaches, muscle spasticity, paralysis and seizure disorders.

• COGNITIVE: Memory deficits (short and long-term), limited concentration, impaired perception and communication, difficulties with reading, writing, planning, and judgment.

• PSYCHO-SOCIAL/BEHAVIORAL/EMOTIONAL IMPAIRMENTS:
  Fatigue, mood swings, denial, anxiety, depression, sexual dysfunction/dyscontrol, lack of motivation, and problems with interpersonal skills.

Prevention

Universal use of helmets by all bicyclists could prevent as many as 2,500 deaths and 757,000 brain injuries (i.e. one death every day and one brain injury every four minutes). According to the National Association of Governors' Highway Safety Representatives, brain injury is the leading cause of death in bicycle crashes.

Wearing helmets can reduce the risk of TBI by 85 percent. The use of helmets significantly reduced the incidence of severe brain injury in the nonintoxicated individual but provided no such protection for the intoxicated (Solomon and Sparadeo 1992). Mortality is reduced by 38% when motorcyclists wear helmets, and the frequency of hospitalization and severity of injuries decline significantly (Kraus 1995b). Studies suggest that mortality can be reduced to 40% in people who sustained brain injuries with timely surgical intervention and case monitoring (Miller 1993).

Maintaining a trauma center with enhanced emergency transport may reduce TBI by 20% (Kraus 1995a). Among survivors, outcome seems to depend on two factors: a) tear necrosis or nerve tissue degeneration and b) swelling of the brain tissues leading to the nerve tissue necrosis. Unless these factors are prevented, permanent brain damage will certainly follow (Kraus 1995b).

Data from the Heath Services Cost Review Commission

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