Westmead Post-Traumatic Amnesia Scale

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Westmead Post-Traumatic Amnesia Scale
PurposeDetermine length of post-traumatic amnesia following traumatic brain injury

The Westmead Post-traumatic Amnesia Scale (WPTAS) is a brief bedside standardised test that measures length of post-traumatic amnesia (PTA) in people with traumatic brain injury. It consists of twelve questions that assess orientation to person, place and time, and ability to consistently retain new information from one day to another. It is administered once a day, each and every day, until the patient achieves a perfect score across three consecutive days, after which the individual is deemed to have emerged from post-traumatic amnesia. [1] PTA may be deemed to be over on the first day of a recall of 12 for those who have been in PTA for greater than four weeks. [2] The WPTAS is the most common post-traumatic amnesia scale used in Australia and New Zealand. [3]

Contents

While other tests of post-traumatic amnesia, such as the Galveston Orientation and Amnesia Test, tend to focus on the patient’s memories of the injury, which rely on potentially biased recall and unverifiable information, the WPTAS is composed of objective items that examine orientation and the ability to consistently retain simple information from one day to another.

An abbreviated version of the WPTAS, the Abbreviated Westmead PTA Scale (AWPTAS), [4] has been developed to assess patients with mild traumatic brain injury. [5] [6]

Rationale and Development

The WPTAS was created in the 1980s and is an extension of The Oxford Scale. [7] It was developed in response to the need for an objective measure of PTA following traumatic brain injury that examines not only orientation to person, place and time, but also crucially the ability to consistently remember new information from one day to another. [8]

The rationale for devising a post traumatic amnesia scale that adequately measures the ability to reliably lay down new memories is based on the “islands of memory” phenomenon, not uncommonly seen in the acute stages of severe traumatic brain injury, and recognised as early as 1932 by W.R. Russell. [9] Russell observed that patients in the acute stage of a brain injury may demonstrate brief periods of sound memory of their surroundings, though such moments of clarity were nevertheless often found to be followed by further periods of confusion and amnesia. [10] Symonds & Russell subsequently warn that it is an error to assume an individual has emerged from PTA based on his or her apparent sound awareness and memory at one particular point of observation; an error which may result in underestimating PTA duration.

Testing

The WPTAS takes approximately three minutes and is administered according to specific guidelines. [11] The scale is first administered once a patient is conscious and able to communicate (either verbally or non-verbally).

On the first administration, the patient is asked seven questions related to orientation (e.g. “what day of the week is it?”). Thus, the most a patient can score on the first day of testing is 7/7. Following the seven questions, the patient is then given the opportunity to learn information which will form part of five additional memory questions that are asked on subsequent PTA testing. This includes the patient being shown three pictures and being specifically asked to remember the three pictures for tomorrow when they are tested again. For each subsequent day, the patient is asked the seven orientation questions and the five memory questions. Thus, from the second day of testing onwards the test is out of 12. The three pictures that the individual needs to remember remain the same for each daily administration until the patient achieves a perfect score of 12/12. When the patient achieves 12/12, the patient is then asked to remember three different pictures for the next day. Testing is ceased once a patient achieves 12/12 on three consecutive days. Duration of PTA is calculated as being from the time of the accident until the first day of the three consecutive days in which the individual achieves a score of 12/12. That is, the beginning point in which the individual demonstrated continuous memory across three consecutive days, or the first day of a score of 12 for those patients who have been in PTA for greater than four weeks.

The WPTAS is administered in a quiet environment that does not contain obvious cues around the patient that could assist them with answering the orientation questions (e.g. clocks or calendars). The scale can be adapted to be used for patients who are unable to communicate verbally.

The severity of injury is based on the time it takes for an individual to emerge from PTA. The Westmead PTA Scale utilises the severity classification system developed by previous PTA research. [12]

Duration of PTASeverityAppropriate Measure
Less than 24 hoursMildAWPTAS
1–7 daysSevereWPTAS
1–4 weeksVery SevereWPTAS
> 4 weeksExtremely SevereWPTAS

WPTAS Severity Classification

Given the design of the scale, The WPTAS is only appropriate to use for individuals with PTA duration greater than 24 hours. An abbreviated version of the WPTAS, the AWPTAS, [4] can be used to measure PTA duration in individuals with a PTA of less than 24 hours.

Research

The WPTAS was designed for patients with closed traumatic brain injury, and subsequent research on the scale has centred on this clinical population. The WPTAS has been found to have high interrater reliability [13] and predictive validity. [14] [15]

Although originally designed for assessing PTA in adult populations, preliminary normative data from hospitalised non head-injured children suggests that the WPTAS may be suitable for use in children as young as eight years of age. [16] Research suggests that the WPTAS may not be appropriate in children younger than seven years of age given that very few non head-injured 6-7 year olds are able to achieve the required criteria of the scale (i.e. perfect scores across three consecutive days). [16]

Abbreviated Westmead PTA Scale

The AWPTAS, [17] [4] derived from the Revised WPTAS, [5] [6] includes the five verbal orientation items from the Glasgow Coma Scale (GCS) and three picture cards used to measure memory. The RWPTAS has been shown to be more accurate than the Glasgow Coma Scale in the identification of cognitive deficits in patients with mild TBI. [6] The A-WPTAS is administered hourly rather than daily. It is used for measuring the length of PTA following a mild traumatic brain injury (that is, when PTA is less than 24 hours).

The AWPTAS is administered according to specific guidelines. A patient is considered to be out of PTA the first time they attain optimal scores of 18 out of 18 (15 out of 15 on the GCS, 3 out of 3 on the picture cards.

Related Research Articles

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A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. The person may experience respiratory and circulatory problems due to the body's inability to maintain normal bodily functions. People in a coma often require extensive medical care to maintain their health and prevent complications such as pneumonia or blood clots. Coma patients exhibit a complete absence of wakefulness and are unable to consciously feel, speak or move. Comas can be derived by natural causes, or can be medically induced.

<span class="mw-page-title-main">Head injury</span> Serious trauma to the cranium

A head injury is any injury that results in trauma to the skull or brain. The terms traumatic brain injury and head injury are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of injuries, there are many causes—including accidents, falls, physical assault, or traffic accidents—that can cause head injuries.

<span class="mw-page-title-main">Brain damage</span> Destruction or degeneration of brain cells

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<span class="mw-page-title-main">Concussion</span> Type of traumatic brain injury

A concussion, also known as a mild traumatic brain injury (mTBI), is a head injury that temporarily affects brain functioning. Symptoms may include loss of consciousness; memory loss; headaches; difficulty with thinking, concentration, or balance; nausea; blurred vision; dizziness; sleep disturbances, and mood changes. Any of these symptoms may begin immediately, or appear days after the injury. Concussion should be suspected if a person indirectly or directly hits their head and experiences any of the symptoms of concussion. Symptoms of a concussion may be delayed by 1–2 days after the accident. It is not unusual for symptoms to last 2 weeks in adults and 4 weeks in children. Fewer than 10% of sports-related concussions among children are associated with loss of consciousness.

In neurology, retrograde amnesia (RA) is the inability to access memories or information from before an injury or disease occurred. RA differs from a similar condition called anterograde amnesia (AA), which is the inability to form new memories following injury or disease onset. Although an individual can have both RA and AA at the same time, RA can also occur on its own; this 'pure' form of RA can be further divided into three types: focal, isolated, and pure RA. RA negatively affects an individual's episodic, autobiographical, and declarative memory, but they can still form new memories because RA leaves procedural memory intact. Depending on its severity, RA can result in either temporally graded or more permanent memory loss. However, memory loss usually follows Ribot's law, which states that individuals are more likely to lose recent memories than older memories. Diagnosing RA generally requires using an Autobiographical Memory Interview (AMI) and observing brain structure through magnetic resonance imaging (MRI), a computed tomography scan (CT), or electroencephalography (EEG).

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Post-traumatic amnesia (PTA) is a state of confusion that occurs immediately following a traumatic brain injury (TBI) in which the injured person is disoriented and unable to remember events that occur after the injury. The person may be unable to state their name, where they are, and what time it is. When continuous memory returns, PTA is considered to have resolved. While PTA lasts, new events cannot be stored in the memory. About a third of patients with mild head injury are reported to have "islands of memory", in which the patient can recall only some events. During PTA, the patient's consciousness is "clouded". Because PTA involves confusion in addition to the memory loss typical of amnesia, the term "post-traumatic confusional state" has been proposed as an alternative.

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The California Verbal Learning Test (CVLT) is one of the most widely used neuropsychological tests in North America. As an instrument, it represents a relatively new approach to clinical psychology and the cognitive science of memory. It measures episodic verbal learning and memory, and demonstrates sensitivity to a range of clinical conditions. The test does this by attempting to link memory deficits with impaired performance on specific tasks. It assesses encoding, recall and recognition in a single modality of item presentation (auditory-verbal). The CVLT is considered to be a more sensitive measure of episodic memory than other verbal learning tests. It was designed to not only measure how much a subject learned, but also reveal strategies employed and the types of errors made. The CVLT indexes free and cued recall, serial position effects, semantic clustering, intrusions, interference and recognition. Delis et al. (1994) released the California Verbal Learning Test for Children (CVLT-C). The California Verbal Learning Test-II (CVLT-II) is an updated version of the original CVLT, which has been standardized and provides normative data.

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<span class="mw-page-title-main">Altered level of consciousness</span> Measure of arousal other than normal

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The Galveston Orientation and Amnesia Test (GOAT) is a measure of attention and orientation, especially to see if a patient has recovered from post-traumatic amnesia (PTA) after a traumatic brain injury. This was the first measure created to test post-traumatic amnesia, and is still the most widely used test. The test was created by Harvey S. Levin and colleagues (1979), and features ten questions that assess temporal and spatial orientation, biographical recall, and memory. Points are awarded for responses to each question, with a 100 points possible. A score greater than 78 for three consecutive days is considered the threshold for emergence from post-traumatic amnesia. This test is intended for patients aged 15 years or older. Younger patients are given a modified version of the test, known as the Children's Orientation and Attention Test (COAT).

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