The severity of damage to the brain after an injury is the primary factor in predicting the injury's impact on the individual. Brain injury is typically categorized as mild, moderate, or severe.
| Mild Brain Injury | Moderate Brain Injury | Severe Brain Injury |
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A severe brain injury may cause the individual to experience an unconscious state, where one appears to be in a deep sleep and cannot be aroused or respond purposefully. Assessments will typically reveal that the individual has no sleep and wake cycles. This loss of consciousness (LOC) is referred to as a coma. Depending on varying factors and the severity of injury, the individual may remain in a coma, emerge from a coma, or experience an increased level of consciousness.
A person who is truly in a coma will not be considered for any type of brain injury rehabilitation program. People can, however, experience different states of consciousness after brain injury. Understanding these disorders of consciousness can be important when discussing treatment and possible rehabilitation options.
Vegetative State
An individual is unaware, but begins to have sleep and wake cycles; normal digestion, breathing, and heart rates; and may open his or her eyes. The individual may occasionally respond to stimuli.
Persistent Vegetative State
Doctors consider a person to be in a persistent vegetative state one year after traumatic brain injury or three to six months after a hypoxic or anoxic brain injury.
Minimally Conscious State
An individual shows slight but definite self-awareness or awareness of their environment.
Locked-in Syndrome
An individual can only move his or her eyes, not any other part of their body, and is conscious and able to think.
Brain Death
A person with brain death is not alive because all the brain functions, including the brain stem, no longer work.
