Reporting and interpreting guidelines

Reporting guidelines

The convention for reporting PTA testing results, at Westmead Hospital, is as follows:

Record the date and report the patient's score. Then outline the items the patient answered incorrectly. (This will provide more information to those unfamiliar with the scale.)

Whenever the patient scores 12 out of 12 you should also record that the picture cards have been changed for the following day. (There is no need to record the new picture cards in the medical record as this should have already been done on the MR-120 Form.)

This is how you should report the results once the patient scores 12 out of 12 for 2 days in a row:

Remember: The operational definition of PTA is that patients must score 12 out of 12 for 3 consecutive days.

When the patient has scored 12 out of 12 for 3 consecutive days this is how you report their results:

Remember: PTA is judged to have ended on the first of the 3 consecutive days of perfect recall.

Finally, prior to discharge, the MR-120 Form should be placed in the patient's medical record file.

Interpreting guidelines

Classification of severity

The standard classification of head trauma severity based on the duration of PTA is from Jennett & Teasdale (1981) and is reproduced below. This classification system is an expanded version of the system developed by Russell & Smith (1961).

Once the patient is out of PTA they should be classified according to this system.

Please note: PTA is calculated from the time of the accident. It therefore includes the period of coma.

Alternative explanations

Poor performance on the Westmead PTA Scale could be due to a number of other factors apart from post-traumatic amnesia. These include: poor motivation; malingering; medication effects; a further episode of head trauma, perhaps the patient fell out of bed; an undetected episode of hypoxia, for example when the patient needed emergency resuscitation; failure to diagnose any premorbid difficulties or problems, like a previous learning disorder; or an undetected communication disorder like dysphasia or dyspraxia. These must be ruled out in order to convincingly demonstrate that the patient is still in PTA.

This is where close observation and accurate record keeping on the part of the PTA examiner is vital, as the information collected can be used to see if a pattern emerges from the patient's test behaviour. For instance: the patient may have a problem with a particular part of the scale (like the picture cards); or they may consistently require the use of a particular test procedure (like the choice of 3 options for Question 5). This test behaviour can then be analysed with regard to other evidence or behaviour observed by staff. Discuss this information with the Clinical Neuropsychologist who will then make an entry in the medical record if they believe a patient's performance on the scale is being adversely affected.

This section emphasises Dr. Shores' rule (from the original PTA manual) when using the Westmead PTA Scale:

'The patient should not be diagnosed as being in PTA on the basis of a poor performance on the Westmead PTA Scale only until other possibilities have been confidently excluded.'

Another explanation to keep in mind is that the patient may be suffering chronic amnesia (see the Chronic Amnesic Patients section).

As can be seen from this section, the Clinical Neuropsychologist is central to the PTA testing enterprise. They interpret PTA results and determine whether patients are suitable for continued testing. Examiners need to be in close contact with the Clinical Neuropsychologist when they encounter difficulties or when new information about a patient's history comes to light. Only the Clinical Neuropsychologist can make an entry which can terminate PTA testing. (For units which do not have access to a Clinical Neuropsychologist the Team Leader takes on these responsibilities.)

In our experience, the recovery from PTA can be either slow and gradual or very abrupt. In both cases when the patient is out of PTA they appear more awake, more alert, more willing to interact with others and more responsive to therapy.