Severity of traumatic brain injury
Severity
Traumatic brain injuries vary enormously in severity from mild tro very severe.
The following are examples of impacts for different levels of severity.
Mild TBI
A mild TBI is also called a concussion. Most people with mild TBI make a good physical recover, some experience ongoing problems with living and learning (mild-complicated).
Moderate TBI
Examples of impacts of moderate TBI are motor coordination difficulties, inability to organise, may require different work. About one third of people with a moderate brain injury experience lifetime problems with living and learning.
Severe TBI
Examples of impacts of severe TBI are decreased ability or inability to control movement, decreased ability or inability to communicate, requires support with daily living, not able to work or able to go back to work with return to work programs and support. 90% of people with a severe brain injury experience lifetime problems with living and learning.
Very severe TBI
Examples of impacts of very severe TBI are inability to control movement, inability to communicate, requires 24 hour support; e.g. very severe TBI with minimal or no physical injury but still requires 24 hour support because of cognitive difficulties. 100% of people with a severe brain injury experience lifetime problems with living and learning.
Measuring severity
There are two common ways of measuring the injury’s initial severity:
Duration of unconsciousness (coma) as measured by the Glasgow Coma Scale
Duration of Post-Traumatic Amnesia
Glasgow Coma Scale
The impact of the injury on the brain determines severity and ranges from concussion to persistent vegetative states and is typically classified from mild to very severe, according to the duration of unconsciousness (coma) as measured by the Glasgow Coma Scale. (Teasdale, G. Jenntt, B., Assessment of coma and impaired consciousness. A practical scale. Lancet 1974; 2: 81-84)
Injury severity category |
Initial Glasgow Coma Scale |
Mild |
12–15 |
Moderate |
9–11 |
Severe |
3–8 |
Very severe |
— |
Duration of Post-Traumatic Amnesia
However, not everyone with a brain injury experiences a loss of consciousness or confusion as the immediate result of a TBI.
Some people with a penetrating injury may initially be conscious following the injury. Some people have a hit on the head and get confused without ever losing consciousness. A football player after a heavy tackle may be confused or unsteady on their feet over a few minutes (this would be classified as a mild TBI and often in sport referred to as a concussion). Ruff, RM, Iverson, GL., Barth, JT., Bush, SS and Broshek, DK, the NAN Policy and Planning Committee Recommendations for diagnosing a mild traumatic brain injury: a National Academy of Neuropsychology education paper. Arch Clin Neuropsychol. 2009; 24: 3-10
A critical indicator of severity for TBI is the length of post traumatic amnesia (evidenced by a period during which the person is disorientated, unable to learn, not know time, place, person (self). They may display behaviours quite different than usual, being disinhibited, irritable or agitated.
Injury severity category |
Duration of |
Mild |
Less than 24 hours |
Moderate |
1–7 days |
Severe |
1–4 weeks |
Very severe |
More than 4 weeks |
Source: Khan et al, 2003
