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Rehabilitation Institute of Chicago: LIFE Center

Brain Injury: Severity Levels and the Recovery Process

Reviewed July 2015
Author: Rehabilitation Institute of Chicago - Brain Injury Team

When defining the severity of a brain injury, health care professionals will often distinguish among mild, moderate and severe. These categories are important because they provide some information about prognosis (the expectations for recovery). Several different tools are available to define the level of injury. The most widely used method to initially classify the severity of a traumatic brain injury is a scoring system called the Glasgow Coma Scale (GCS). This scale is used to assess the ability to perform several actions. The more the patient is able to do, the higher the score and the less severe the injury.

A GCS score of eight or less after resuscitation from the initial injury is classified as a severe brain injury. The GSC score for a moderate brain injury is between nine and thirteen. A GCS score of thirteen or greater indicates a mild brain injury, or concussion. People with mild brain injuries rarely need inpatient rehabilitation unless they have had injuries to other parts of their bodies.

Glasgow Coma Scale

Eye opening Score Verbal Score Motor Score
None 1 None 1 None 1
To pain 2 Sounds 2 Extension 2
To command 3 Words 3 Flexion 3
Spontaneously 4 Disoriented 4 Withdraws from pain 4
Oriented 5 Localizes to pain 5
Follows commands 6


After someone has sustained a brain injury, family and friends want to know how long recovery will take and how much function will be recovered. These are very difficult questions to answer because there are many uncertainties about brain injuries. The health care team will provide the most accurate estimation of recovery that they can. Sometimes, however, the most honest response will be a frustrating “We’ll just have to wait and see.” Many factors affect the prognosis after brain injury:

  • Previous medical history including any neurological problems;
  • Age;
  • Type and location of the injury;
  • Depth and duration of coma;
  • Presence of low blood pressure or oxygen levels after the injury;
  • Current findings from physical examinations, radiological studies of the brain and other tests.

Recovery Process

The fact that the brain recovers at all is remarkable in many ways. A brain injury causes the death of brain cells (neurons). Unfortunately, the brain is one of the few places in the body where cells do not seem to regenerate. Yet, people with brain injuries often make tremendous gains. Scientists are still unsure about all of the mechanisms that allow for brain recovery. Possibilities include:

  • Some neurons may be just bruised or swollen and not permanently damaged. As the bruising and swelling improve, the neurons start to function again.
  • Other parts of the brain take over the functions of the damaged areas.
  • New connections between the remaining brain cells may form.

Regardless of the reasons, people can get better after a brain injury, but predicting the degree and rate of recovery is very difficult.

Recovery after a brain injury goes through a series of stages. These stages represent only general categories. Sometimes, recovery can stop at one of these stages and not progress to the next stage. The transition between stages is usually very gradual. Every person recovers at a different pace, so it is difficult to compare the experience of one person to another.

Much of the recovery after a brain injury occurs early on – usually within the first six months. Most experts agree that the brain can continue to heal for up to two years after an injury. Even after two years, people may slowly improve. The reason for this continued progress is that many of the gains after the first year or two do not depend so much on the healing of the brain, as on the learning of new skills. Although impairments, such as muscle weakness or poor memory, may not change at this point, people who are recovering are learning ways to compensate and become more functional. The recovery process at this point is more like being back in school than recuperating from a surgery.

Stages of Recovery

  • Coma;
  • Vegetative state;
  • Minimally conscious state;
  • Recovery of full consciousness which often includes post traumatic amnesia.


The initial stage after a severe brain injury is a coma, a state of unconsciousness. People in a coma are unaware and unresponsive, but not asleep as there is no sleep-wake cycle. While in a coma, people are unable to speak, follow commands or open their eyes. As a person’s GCS score improves, he or she is considered to be emerging from the coma. These changes usually take place gradually. For instance, eyes may open or there may be evidence of sleep cycles, but still no ability to speak or follow commands. As these abilities appear, most rehabilitation centers will use the Rancho Los Amigos Cognitive Scale (see separate document) to describe progress after this point.

Vegetative State

Sometimes emergence from coma can seem to stop before the person becomes conscious. The term vegetative state may be used to describe this. People in a vegetative state may open their eyes and have sleep-wake cycles, but are still unconscious. Although not considered to be in a coma, the patients remain totally unaware. In a vegetative state, any apparent signs of responding to surroundings are reflexes and not indications of awareness. The term permanent vegetative state is used only when a person is determined to be in a vegetative state for twelve months after trauma or three months after a brain injury that caused oxygen insufficiency. Always discuss with the physician questions about responses and awareness.

Minimally Conscious State

The term minimally conscious state refers to people who demonstrate some, but very little, awareness and responsiveness to their surroundings. Responses are typically inconsistent and thus not considered comatose or vegetative. As the name suggests, a person is considered conscious in this state. Occasionally, physicians may prescribe medicines that help stimulate the brain, especially if a person is not becoming more responsive with time. Some people do not progress beyond this stage in their recovery process.

Post Traumatic Amnesia

Most people after an injury enter the state called post-traumatic amnesia. This is a stage which is characterized by serious memory problems. It does not, however, refer to all problems with memory after a brain injury. Post-traumatic amnesia is a technical term that describes the stage after emerging from coma. Its main feature is the inability to remember any information from day to day. As a result, the person with a brain injury is disoriented and confused no knowing where they are or what has happened to them. This does not mean that a person is unable to benefit from therapies. In this state, people are often able to learn basic skills even without remembering that they learned them! This is sometimes referred to as procedural or implicit memory.

In addition to having memory problems, people in post-traumatic amnesia are often agitated. Some of this agitation is a result of the brain injury itself, and some is simply a response to the feeling of confusion. It can be a frightening experience to see a loved one during this time. It is important to remember that the behavior is not under the patient’s control. Physicians may sometimes order medicines to help relieve some of the agitation. In addition, some sort of physical restraint, such as a special bed or mitts, may be necessary to prevent people in this stage from hurting themselves or others.

Post-traumatic amnesia is thought to resolve when someone is able to consistently remember basic information from day to day. Most likely, however, memories from a short time before the accident will never be recovered. Problems with memory can persist even though post-traumatic amnesia has resolved. After the resolution of post-traumatic amnesia, further recovery continues. Again, it is extremely difficult to predict just how quickly and how much recovery to expect.

Reference: Rancho Levels Of Cognitive Functioning: A Clinical Case Management Tool Third Edition, Chris Hagen; 1998, reprinted with permission from Rancho Los Amigos, Downey, California.

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