EWJ Dec 2023 - Journal - Page 54
It is important to be aware that, "the GCS remains the
main instrument for classifying the severity of
TBI...(but)….the duration of PTA is widely used as an indicator of injury severity and reported to be a strong predictor of outcome" (Lancet, 2022, p.1024)
according to standardised instructions (intra-rater
reliability and validity). Assessors need to be aware that
the patient may be aphasic or lack the ability to communicate reliably but be fully orientated. This can
confound measures of PTA which are administered
and scored according to the verbal responses of the
patient.
• Evidence of brain injury from neuroradiological
investigations
Most “milder” brain injuries tend to be routinely
investigated by CT scan which may not sufficiently
sensitive to detect axonal or vascular injuries which
can then be (erroneously) excluded (Sharp & Jenkins,
2015). In addition, there is an imperfect correlation
between neuropathology and functional and/or cognitive impairment which needs to be considered (Allen
et al, 2013, Bunnage 2013).
Poor performance on the WPTAS 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, (such as falling whilst an inpatient); an undetected episode of hypoxia, (in cases where there has
been emergency resuscitation); failure to diagnose
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.
What is PTA?
The interval from the injury until the patient is
orientated and can form and recall new memories. A
person in PTA can often appear to be engaging normally with those around them but are unable to lay
down new memories and, as a result, can subsequently
appear confused or disorientated.
Classification of TBI
(The MAYO system, Malec et al, 2007)
Classify as Moderate–Severe (Definite) TBI if one or
more of the following criteria apply:
• Death due to this TBI
• Loss of consciousness of 30 min or more
• Post-traumatic anterograde amnesia of 24h or more
• Worst Glasgow Coma Scale full score in first 24 h