Below is a list of terms and definitions that refer to the different injuries of TBI.
Acquired Brain Injury- injuries other than congenital, birth trauma, hereditary or degenerative. This includes traumatic brain injury. In the non-traumatic types of acquired brain injury, the brain is usually diffusely injured. These injuries are usually not included in TBI but the symptoms span the same spectrum. Common causes are anoxia and hypoxia. These are lack of oxygen to the brain and insufficient oxygen to the brain. They can occur because of mechanical problems with breathing, with cardiac arrest or bleeding. Drugs and poisoning can also cause acquired traumatic brain injury. Carbon monoxide poisoning is an example of poisoning that may cause brain injury.
ASCOT - The ASCOT probability of survival encapsulates several of the variables measured in the Glasgow Coma Scale but also includes systolic blood pressure, respiration rates upon admission, and anatomic injuries. The ASCOT was found to be the most sensitive tool for determining severity of head injuries in children and is effective in predicting the outcome of injury.
Cerebral Contusion- This is essentially a bruise to the brain tissue. The fact that they are localized makes them different than concussions
Closed Head Injury- A type of Traumatic Brain Injury in which the skull and dura mater remain intact. Closed head injuries are the leading cause of death in children under 4 years old and the most common cause of physical disability and cognitive impairment in young people.
Concussion - This is a common closed head injury that results in an interruption of normal brain function.
Diffuse Axonal Injury- An injury to the axon of the neuron. These injuries frequently result from car, truck or motorcycle accidents and often lead to comas and permanent brain damage.
Dura mater - The outermost of the three layers of the meninges (a system of membranes) surrounding the brain and spinal cord. The dura mater is frequently referenced in discussion of TBI because it is the membrane closest to the skull.
Glasglow Coma Scale - The Glasgow Coma Scale is commonly used to assess the severity of traumatic brain injuries, including closed head injuries. The scale tests a patient's eye, verbal, and motor responses. The scale goes up to fifteen points; with fifteen being the most mild injury, less than eight being a severe brain injury, and three being a vegetative state.
Intracranial hematoma - a condition in which a blood vessel ruptures causing a pool of blood to form around the brain (subdural hematoma) or between the brain and the skull (epidural hematoma). Intracranial hematoma causes an increase in pressure on the brain.
Movement disorders - Conditions that may develop after a TBI, which include tremors, ataxia (Uncoordinated muscle movement), myoclonus (shock-like contractions of muscles), and loss of movement range and control - particularly with a loss of movement repertoire.
Open Head Injury or Penetrating Head Injury- is a head injury in which the dura mater, the outer layer of the meninges, is breached. Penetrating injury can be caused by high-velocity projectiles or objects of lower velocity such as knives, or bone fragments from a skull fracture that are driven into the brain.
Post-concussion syndrome - A set of lasting symptoms experienced after mild TBI, can include physical, cognitive, emotional and behavioral problems such as headaches, dizziness, difficulty concentrating, and depression.
Post-traumatic seizures - seizures that result from a TBI, which increases the severity of trauma. During seizures the amount of oxygen available to the brain is reduced the pressure within the intracranial space rises. People who suffer TBI are often given anticonvulsant medications as a precaution against seizures. Around 5-7% of people hospitalized with TBI have at least one seizure.
Secondary Injury- a complex set of cellular processes and biochemical cascades that occur in the minutes to days following the trauma. These secondary processes can dramatically worsen the damage caused by primary injury and account for the greatest number of TBI deaths occurring in hospitals.
Secondary Injuries Include:
- Intracranial hemorrhage (bleeding inside the skull)
- Brain swelling
- Increased intracranial pressure (pressure inside the skull)
- Brain damage associated with lack of oxygen
- Infection inside the skull, common with penetrating trauma
- Chemical changes leading to cell death
- Increased fluid inside the skull (hydrocephalus)