Measure of<unk>  brain injury severity + Levels of TBI severity GCS<unk>  LOC Mild 13–15 hour minutes Moderate 9–12 30 minutes–24 hours 1–24 hours Severe 3–8 > 1 day > 24 hours + TBI severity using<unk>  alone Severity<unk>  Very mild 4 weeks<unk>  has been proposed to be the best measure of head trauma severity, but it may not be a reliable indicator of outcome. However,<unk>  duration may be linked to the likelihood that psychiatric and behavioral problems will occur as consequences of TBI. Classification systems for determining the severity of TBI may use duration of<unk>  alone or with other factors such as Glasgow Coma Scale (GCS) score and duration of loss of consciousness (LOC) to divide TBI into categories of mild, moderate, and severe. One common system using all three factors and one using<unk>  alone are shown in the tables at right. Duration of<unk>  usually correlates well with GCS and usually lasts about four times longer than unconsciousness.<unk>  is considered a hallmark of concussion, and is used as a measure of predicting its severity, for example in concussion grading scales. It may be more reliable for determining severity of concussion than GCS because the latter may not be sensitive enough; concussion sufferers often quickly regain a GCS score of 15. Longer periods of<unk>  or loss of consciousness immediately after the injury may indicate longer recovery times from residual symptoms from concussion. Increased duration of<unk>  is associated with a heightened risk for TBI complications such as<unk><unk>  epilepsy. Assessment Duration of<unk>  may be difficult to gauge accurately; it may be overestimated (for example, if the patient is asleep or under the influence of drugs or alcohol for part of the time) or underestimated (for example, if some memories come back before continuous memory is regained). The Galveston Orientation and<unk>  Test (GOAT) exists to determine how oriented a patient is and how much material they are able to recall. The GOAT is the most widely used standardized scale for the prospective assessment of<unk>  in the United States and Canada. The test is made up of 10 items that assess orientation and recollection of the events before and after the injury. It can be used to assess the duration of<unk> ; this particular GOAT assessment has been found to strongly predict functional outcome as measured by the Glasgow Outcome Scale, return to productivity, psychosocial function and distress. An alternative to the GOAT is the Westmead<unk>  Scale (WPTAS) which examines not only orientation to person, place and time, but also crucially the ability to consistently remember new information from one day to the next. It consists of twelve questions (seven orientation questions, and five memory items) and is administered once daily, each and every day, until the patient scores a perfect score of 12/12 on three consecutive days. It is suitable for patients with moderate to severe<unk>  brain injury. The WPTAS is the most common<unk>  scale used in Australia and New Zealand. An abbreviated version has been developed to assess patients with mild<unk>  brain injury, the Abbreviated Westmead<unk>  Scale (AWPTAS). Testing Before the development of the current tests for the assessment of<unk>  <unk> , a retrospective method was used to determine the patient's condition, consisting of one or more interviews with the patient after the episode of<unk>  was judged to be over. The retrospective method, however, fails to account for the apparent lucidity of patients who are still experiencing substantial disorientation, or the finding that the recovery from<unk>  is often characterized by the presence of "islands of memory" (short periods of clarity). A failure to take these facts into consideration may have biased retrospective methods towards underestimating the length and severity of an episode of<unk> . Also, the retrospective method relies on retrospective memory, one's memory for past events, which is not very reliable in healthy individuals, and even less so in patients who have recently experienced a<unk>  brain injury (TBI). Patients may also unconsciously or consciously bias their answers because they want to appear more healthy or more ill than they truly were, or because of poor insight. The retrospective method is also flawed because there is no standard measurement procedure. Although the retrospective method may provide useful subjective data, it is not a useful tool for measurement or categorization. GOAT The Galveston Orientation and<unk>  Test (GOAT) is the most frequently used test for assessing<unk>  in the United States and Canada. 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. Scores of 75 or more on this scale (out of a total possible score of 100) correspond to the termination of the<unk>  episode. The GOAT typically classifies orientation into three categories: orientation to the person, orientation to the place, and orientation to the time. The idea behind these questions is that each of these classifications places a large demand on the patient's memory and learning abilities. WPTAS and AWPTAS The Westmead<unk>  Scale (WPTAS) is commonly used in Australia and New Zealand. It questions twelve questions that examine orientation to person, place and time, in addition to the ability to consistently remember new information from one day to the next. The scale is administered once each day, until the patient scores 12/12 on three consecutive days. The WPTAS is suitable for patients with moderate-to-severe<unk>  brain injury. An abbreviated version of the WPTAS, the Abbreviated Westmead<unk>  Scale (AWPTAS) assesses patients with mild<unk>  brain injury. Drawbacks Although the GOAT has proved useful in acute care, recent research has called attention to some of its drawbacks. The GOAT's assessment of orientation may put too much of a focus on memory as the main mechanism behind orientation. The range of cognitive and behavioral symptoms associated with<unk>  seems to indicate that the patient's disorientation is more than just a memory deficit. Consequently, it may be beneficial to incorporate tests of other cognitive functions, such as attention, which relate to both memory and orientation. Another recent study compared the success of the GOAT and the Orientation Log (O-Log) in predicting rehabilitation outcomes, and found that, while the O-Log and the GOAT perform similarly as measures of<unk>  severity and duration, the O-Log provides a more accurate picture of rehabilitation. While the GOAT is a useful tool, these results suggest that using alternative methods of assessing<unk>  may increase the amount of information available to physicians and may help in predicting rehabilitative success. The international cognitive (INCOG) expert panel has recommended the use of a validated<unk>  scale such as the GOAT or WPTAS for assessing<unk>  duration in patients with moderate-to-severe<unk>  brain injury on a daily basis. Severity The severity of<unk>  <unk>  is directly related to its duration, although a longer duration does not necessarily indicate more severe symptoms. The duration of<unk>  in brain-injured patients is a useful predictor of the expected long-term effects of the injury, along with the duration of loss of consciousness(LOC), and scores on the Glasgow Coma Scale (GCS), which measures degrees of consciousness, with higher scores indicating higher levels of functioning. A score of three indicates complete unconsciousness, and a score of 15 indicates normal functioning. + Levels of TBI severity GCS score duration of<unk>  duration of LOC Mild 13–15 hour minutes Moderate 9–12 30 minutes – 24 hours 1–2 24 hours Severe 3–8 > 1 day > 24 hours In patients experiencing<unk>  for the duration of: Up to one hour – the injury is very mild in severity and full recovery is expected. The patient may experience a few minor<unk> -concussive symptoms (e.g. headaches, dizziness). 1–24 hours – the injury is moderate in severity and full recovery is expected. The patient may experience some minor<unk> -concussive symptoms (e.g. headaches, dizziness). 1–7 days – the injury is severe, and recovery may take weeks to months. The patient may be able to return to work, but may be less capable than before the injury. 1–2 weeks – the injury is very severe, and recovery is likely to take many months. The patient is likely to experience long-lasting cognitive effects such as decreased verbal and nonverbal intelligence as well as decreased performance on visual tests. Patients should, however, still be able to return to work. 2–12 weeks – the injury is very severe, and recovery is likely to take a year or more. The patient is likely to exhibit permanent deficits in memory and cognitive function, and the patient is unlikely to be able to return to work. 12+ weeks – injury is very severe and accompanied by significant disabilities that will require long-term rehabilitation and management. The patient is unlikely to be able to return to work. Note: return to work is meant to indicate a return to a reasonable level of functionality, both in professional and personal
Post-traumatic amnesia
Excited delirium
Drug-induced amnesia
Childhood amnesia
Transient global amnesia
Memory distrust syndrome
Psychogenic amnesia
Emergence delirium