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Epidemiology Of A Head Injury
- Trauma is the leading cause of death in people younger than 45 in the United States, and brain injury causes more trauma deaths than any other type of injury.
- About 400,000 new cases of brain injury occur each year in the United States. For every 24 people who seek medical treatment for brain injury, about six are admitted to a hospital and one dies from the damage.
- Motor vehicle crashes are the most common cause of head and brain injuries and involve a disproportionately large number of young people. Brain injury occurs twice as often among males compared with females.
- In recent years, injury prevention efforts such as motorcycle helmet and seatbelt laws, infant restraint seats, air bags and stricter drunken driving penalties have helped ease the rate of injury.
- Overall, about half of hospital patients with brain injury have mild trauma, about a quarter have moderate injuries and about a quarter suffer severe, life-threatening damage.
- Patient age and severity of the injury are consistent and major predictors of recovery from brain injury. Nearly all patients with a severe head injury develop some degree of disability, while about two of three patients with moderate brain injury suffer disability. Among patients discharged with doctor expectations of a "good recovery," at least 10 percent to 20 percent suffer ongoing neuropsychological difficulties.
Public education initiatives targeting brain and spinal cord injury, such as Think First, and safety legislation have helped ease the rate of traumatic brain injury.
- From 1982 to 1992, seat belt use among drivers and passengers in the United States increased from 11 percent to 66 percent.
- In 1992, air bags saved more than 550 lives and prevented an estimated 40,000 serious injuries.
- Fatalities from motorcycle use have fallen from more than 4,600 in 1982 to 2,400 in 1992 in conjunction with implementation of helmet laws.
- Increased use of infant restraint seats from 1982 to 1992 saved more than 2,000 infant lives.
- The pervasive problem of alcohol-related traffic accidents is also starting to diminish due to broad educational efforts and strict enforcement of drunken driving laws. Between 1982 and 1992, alcohol-related traffic deaths fell by more than 30 percent despite a rising number of vehicles on the road.
Glasgow Coma Scale
4 = Spontaneously
3 = To voice
2 = To pain
1 = None
5 = Oriented
4 = Confused
3 = Inappropriate words
2 = Incomprehensible sounds
1 = None
6 = Follows commands
5 = Localizes pain
4 = Withdrawal to pain
3 = Abnormal flexion
2 = Abnormal extension
1 = None
- The Glasgow Coma Scale (GCS) is the most widely used method of defining a patient's level of consciousness. Medical personnel routinely use the scale to objectively describe a patient's neurological status, or brain health.
- The patient's best movement, verbal and eye opening responses determine the GCS:
- A patient who can follow commands, is fully aware and has spontaneous eye-opening scores a GCS of 15.
- No movement, eye opening or verbal response to pain scores a GCS of 3.
- Patients with a GCS of 8 or less are considered to be in a coma.
- Differences in a patient's GCS score compiled by observing medical staff are small when the scale is properly performed. Therefore, a change in the GCS score from one assessment to the next indicates a significant change in level of consciousness.
- Medical staff also use the scale to determine chances of recovery from head injury. Head injury severity is generally categorized into one of three levels based on the GCS after initial treatment:
- Mild (GCS 13-15)
- Moderate (GCS 9-12)
- Severe (GCS 3-8)
Recovery After A Brain Injury
- Even though much is known about different types of head injuries, recovery is difficult to predict. Some patients with severe initial injuries make dramatic recoveries within several months to a year, while patients with milder injuries sometimes encounter chronic neuropsychological and physical problems.
- Factors known to diminish chances of satisfactory neurological and psychological recovery from brain injury include older age (after age 50 or 60), low Glasgow Coma Scale (GCS) score, poor pupil response, low blood pressure or oxygenation following the injury, and prolonged and difficult to control pressure on the brain.
- Symptoms diagnosed with computed tomography (CT) brain scans that diminish chances of a good recovery include acute subdural hematoma, intracerebral hematomas, multiple contusions, subarachnoid hemorrhage and large degrees of brain shift from one side to the other, called midline shift.
- In the most recent reports, 50 percent to 60 percent of brain injury patients enjoyed good recovery or moderate disability. The mortality rate stood at approximately 25 percent.
- Despite intensive treatment, long-term disability occurs in a large portion of the survivors of severe head injury. Significant neuropsychological problems (memory, cognitive and behavioral changes) and physical disabilities are also common in patients sustaining milder injuries.
- Patients with significant cognitive brain function impairment are best managed at a comprehensive rehabilitation unit for several weeks or months after they leave the hospital.
- Recovery of function from the time of discharge to six months post injury can be dramatic, even in some deeply comatose individuals. Improvement generally begins to plateau at six months post injury and typically peaks at one year to 18 months.