Consider the different clinical scenarios which affect when to stop testing with the Westmead Post-Traumatic Amnesia (PTA) Scale.
PTA testing stops when the patient is considered to have emerged from PTA. Based on the Westmead PTA Scale, this is when a patient scores 12 out of 12 over 3 consecutive days (Shores 1986).
Patients being assessed on the Westmead PTA Scale for moderate or severe traumatic brain injury (TBI) remain in the health facility until testing is complete. This means at least 4 days in hospital following the injury.
In some circumstances, a patient may be discharged before testing is complete, only after consultation with a medical specialist in brain injury to ensure a TBI diagnosis is not missed.
Once a person has emerged from PTA, decisions regarding discharge are based on medical stability, personal safety, functional capability and access to further rehabilitation.
Examples
Example 1: Straightforward stop – 3 consecutive scores of 12
Johan is a 28-year-old man involved in a motorbike accident. His ambulance record shows a Glasgow Coma Scale (GCS) reading of 10 at the scene, increasing to 12 when he arrived at the hospital. Witnesses reported a period of unconsciousness of approximately 5 minutes.
In the emergency department, Johan presents as confused, agitated and unable to remember where he is or who is providing care. He is given a provisional diagnosis of traumatic brain injury (TBI) and undergoes neuroimaging. A referral is made to the occupational therapy department for PTA testing.
Following stabilisation, Johan is transferred to the acute neurosurgical ward. PTA testing using the Westmead PTA Scale is started the following day (i.e. 1 day after the TBI).
Johan’s scores using the scale are presented below:
Days from injury | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Score | 6 | 8 | 9 | 10 | 9 | 10 | 11 | 12 | 12 | 12 |
Testing ceases after Day 10 as Johan has now scored 12 on 3 consecutive days. He is considered to have emerged from PTA on the day he scored the first of 3 consecutive scores of 12. The duration of PTA is 8 days, which represents a severe TBI.
Example 2: Delayed start and intermittent scores of 12 before testing stops
Mary is a 50-year-old woman who is unconscious on arrival to hospital following a motor vehicle accident. She is diagnosed with a significant TBI, confirmed with neuroimaging. She requires mechanical ventilation and is treated in the intensive care unit.
Mary is extubated 3 days after her TBI and starts to communicate verbally the following day. PTA testing using the Westmead PTA Scale starts on day 5, as she is responding to questions reliably. Her scores over the following weeks are presented below:
Days from injury | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Score | 4 | 7 | 8 | 6 | 8 | 9 | 9 | 9 | 11 | 10 | 11 | 12 | 11 | 11 | 10 | 12 | 12 | 12 |
On Day 16, Mary first scores 12; however, the following day scores 11. She does not score 12 on 3 consecutive days until day 22, at which point testing ceases. She is considered to have emerged from PTA on the day of her first of 3 consecutive scores of 12, which occurs on day 20.
The duration of PTA is 20 days. This is consistent with a severe TBI.
Patient unable to achieve 3 consecutive scores of 12
There are a small number of patients with very severe brain injuries who have difficulty coping with the demands of the scale. Persevere with PTA testing for as long as possible.
Evidence suggests patients who remain in PTA for more than 28 days have likely emerged from PTA when they first score 12, i.e. obtaining 3 consecutive scores of 12 may be unnecessary (Tate et al. 2006). Seek advice from a clinical neuropsychologist.
Patients emerging from PTA may sometimes struggle to consistently gain full scores, fluctuating between 10 and 12 for a week or 2 without meeting the scale's criteria of 3 consecutive scores of 12. Other team members may report clinical and behavioural improvements in the patient. Seek input from a neuropsychologist or other expert clinician to guide the value of, and indication for, continued testing.
Patient unable to achieve a score of 12
For patients who fail to achieve a single score of 12 after a minimum of 3 months from injury (which implies an extremely severe TBI), seek advice from a clinical neuropsychologist or brain injury rehabilitation service. Continue daily testing (or intermittent testing) to monitor progress and consolidate clinical impressions regarding the patient’s status.
Patients can be considered to have chronic amnesia if they fail to achieve a single score of 12 on the Westmead PTA Scale within the first 6 months from injury (assuming there are no confounding factors present, such as communication impairments).
The treating team should determine neurocognitive assessment and ongoing management, considering the patient’s circumstances and advice from rehabilitation medicine specialists, neuropsychologists and other clinicians. Use clinical judgement and shared decision-making with the patient and their family to determine discharge timing, discharge destination and other plans.
Interrupted testing
Missed days
If a single day of testing is missed due to interruptions such as surgery or relocation to another ward or health facility, do the following:
- Where the patient has not yet scored 12, a brief interruption to testing is unlikely to significantly impact the overall measurement of PTA duration. Document the reason for disruption in the medical record and continue the next day.
- If the patient scores 12 for 2 consecutive days and then misses the next day of testing, followed by a score of 12 on the subsequent day when testing is resumed, this can be considered equivalent to achieving 3 consecutive full scores. PTA is deemed to have ended on the first of the consecutive scores of 12.
- Similarly, if the patient scores 12 but then misses the next day of testing, followed by scores of 12 on the subsequent 2 days, this can be considered equivalent to achieving 3 consecutive full scores. PTA is deemed to have ended on the first day they scored 12, i.e. before the missed day.
Missing 2 or more consecutive days of testing resets the scoring criteria, and 3 subsequent consecutive scores of 12 are needed to clear PTA. Record this in the medical record so PTA duration can be considered along with other clinical indicators.
Post-test deterioration
In circumstances where a patient is considered to have emerged from PTA but then deteriorates cognitively, restart PTA testing only if there is a new TBI, such as a fall with head strike. Consider all possible causes for the cognitive decline, including delirium and seizures. Be confident you are testing for PTA and not cognitive decline due to other conditions. In these situations, consult a clinical neuropsychologist.
Continued confusion following clearance after first 24 hours
There may be circumstances where a patient was deemed to have emerged from PTA after a score of 18 out of 18 on the Abbreviated Westmead PTA Scale (A-WPTAS) used within the first 24 hours following injury, but is observed to be confused and disoriented in the hours or days following.
Use clinical judgement to determine if PTA remains the likely cause for the patient’s presentation. If so, start testing with the Westmead PTA Scale. Explanations for such a disparity may include incorrect administration or reduced sensitivity of the A-WPTAS.
References
- Shores EA, Marosszeky JE, Sandanam J & Batchelor J (1986). Preliminary validation of a clinical scale for measuring the duration of post-traumatic amnesia. Medical Journal of Australia. 144: 569-572.
- Tate RL, Pfaff A, Baguley IJ, Marosszeky JE, Gurka JA et al. (2006). A multicentre, randomised trial examining the effect of test procedures measuring emergence from post-traumatic amnesia. Journal of Neurology, Neurosurgery and Psychiatry. 77(7): 841-849.