Health

Recovery from a traumatic brain injury (TBI) occurs in phases. The three most important phases are coma, post-traumatic amnesia (PTA) and a longer and more variable recovery period.Although the time patients spend in each stage can be very different, the order of the stages is fixed. The length of time a person spends in each stage can indicate how severe his brain injury is and how much recovery can be expected.

Most TBIs begin with a period of unconsciousness (often referred to as a coma). In mild TBI, the loss of consciousness may only last a few seconds. However, in severe TBI, the period of coma can last weeks. Although there are many behaviors that mark the end of coma, the most useful sign is when the person follows instructions (such as, “squeeze my hand”). For most patients, the recovery of consciousness is gradual. It is unusual for someone with a TBI to be unconscious one day and fully conscious the next day. During this period of time, patients may show only intermittent or minimal evidence of being conscious. For instance, they may only squeeze someone’s hand two times out of five or they may only do it in the morning but not in the evening. This period between coma and full consciousness is often called the minimally conscious state.

Even after regaining consciousness, patients can still be very confused. In particular, their ability to remember from day to day (short-term memory) is very impaired. This phase is known as post-traumatic amnesia (PTA). The amnesia does not refer to losing memory for the incident that caused the injury or of their life before the injury. Rather, it refers to the inability to remember from day to day after the injury (for instance, what they had for dinner the night before). The end of PTA is usually determined by the patient’s ability to satisfactorily answer a set of questions that checks their memory. There are several such tests used; the most common one is known as the Galveston Orientation and Amnesia Test (GOAT).  It is very helpful to know when a person comes out of PTA because how long a patient is in PTA is currently the best predictor of how much recovery the person can be expected to have (see Section IX. Prognosis).

Even when the period of PTA has ended, a person can still have problems with short-term memory. In addition, he can have other problems with thinking, for instance, with his attention or speed of thinking. Emotional problems such as irritability are also common. And there might be physical problems such as weakness or problems with balance depending on what other parts of the brain have been injured. These issues are discussed in more detail below.

Prognosis
It can be very difficult to predict what someone’s long-term condition after a TBI will be. However, there are some guidelines that can be used. In general, the most powerful predictors of outcome after TBI are how long a patient is in a coma and in post-traumatic amnesia (PTA). 

Table 3. Prognostic Guidelines after Severe TBI*

In particular, patients who start following commands in less than two weeks or whose length of PTA is less than two months have a very good chance of at least being able to live on their own (even if they can’t return to work or school). On the other hand, patients who don’t start following commands for at least a month or whose length of PTA is longer than three months are unlikely to be able to return to work or school (although they might be able to live on their own). Age is also related to outcome; in general, patients over 65 who have had a severe TBI will be very unlikely to return to work. Unfortunately, neither CT scans nor MRIs are very good at predicting outcome. It is important to keep in mind that there can be exceptions to these guidelines but they do provide a general sense of what one might expect. Prognosis for someone who is in a vegetative state is a little different and is discussed later in the section on disorders of consciousness.