What is Post-Traumatic Amnesia?
Post-traumatic amnesia (PTA) is a state of confusion that occurs following a traumatic brain injury or concussion in which a person is disoriented and unable to remember certain things associated with the event itself and/or remember things before and after the event. The term is also used in a broader context involving the inability of a person, after brain injury, to create new memories. When continuous memory returns, PTA is considered resolved. There are two types of amnesia: retrograde amnesia (loss of memories that were formed shortly before the injury) and anterograde amnesia (problems with creating new memories after the accident).
It is theorized, and some have proposed, that PTA is a good measurement of brain injury severity, at least in the acute (short term) phase of assessment. Most, however, consider it, standing alone, to be less reliable as an indicator of long-term outcome. PTA is a classic sign of concussion and is used in predicting concussion severity, for example in concussion grading scales (mild, moderate, severe).
The severity of PTA is directly related to its duration, although a longer duration does not always indicate a greater severity of brain injury. Duration of PTA may also be difficult to gauge. It may be overestimated (for example, if the patient is asleep or under influence of drugs and alcohol) or underestimated (for example, if some memories come back before continuous memories return).
The Galveston Orientation and Amnesia Test (GOAT)
The GOAT is the most frequently used test for assessing PTA. The test consists of 10 items that involve the recall of events that occurred right before and after the injury, as well as questions about disorientation. The GOAT typically classifies orientation into three categories: orientation to person, place, and time. The test questions are:
- What is your name?
- Where were you born?
- Where do you live?
- Where are you now?(city and building)
- When were you admitted to this hospital?
- How did you get here?
- What is the first event you can remember after the accident?
- What time is it now?
- What day of the week is it?
- What day of the month is it?
- What is the month?
- What is the year?
Amnesia from mild head trauma usually resolves over time without treatment. Amnesia from severe brain injury may not recede, however improvement usually occurs within 6 to 9 months.