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Medical assessor guidance note 5

Mental and Behavioural Disorders Impairment:
Postconcussional Syndrome

Assessment of postconcussional syndrome/postconcussional disorder

This material is issued by the Motor Accidents Authority under s.65(2) of the Motor Accidents Compensation Act 1999 (the Act) in the interests of promoting accurate and consistent medical assessments under the Act. The interpretation provided here is not legally binding but represents the clinically recommended interpretation in an area where more than one interpretation of existing provisions may be possible. This recommended interpretation is publically available. Any medical assessment which does not adopt this interpretation should be accompanied by clinical justification for the interpretation adopted, supported by full, robust reasons.

References

  • The Motor Accidents Authority Permanent Impairment Guidelines – Guidelines for the assessment of permanent impairment of a person injured as a result of a motor vehicle accident 1 October 2007 (MAA Guidelines): clause 5.9 page 31 and Chapter 7 Mental and Behavioural Disorders Impairment page 38.
  • Prigatano G.P. and Gale S.P. The Current Status of Postconcussional Syndrome. Current Opinion in Psychiatry 2011, 24:243-250.

Background

When a person has suffered a head injury and complains of cognitive impairment, they may be assessed under Chapter 5 of the MAA Guidelines. Clause 5.9 of the MAA Guidelines states:

"For an assessment of Mental Status Impairments and Emotional and Behavioural Impairments there should be:

(i) evidence of a significant impact to the head, or a cerebral insult, or that the motor accident involved a high velocity vehicle impact; and

(ii) one or more significant medically verified abnormalities such as an abnormal initial post-injury Glasgow Coma Scale score, or Post Traumatic Amnesia, or brain imaging abnormality."

Some persons will not satisfy the requirements of clause 5.9 of the MAA Guidelines and may be assessed under Chapter 7 of the MAA Guidelines.

Persons who present with a variety of somatic, cognitive, emotional, motor or sensory disabilities ascribed to the concussion may have no convincing historical or clinical evidence of significant brain injury.

Issues requiring clarification

The status of Postconcussional Syndrome (PCS)/Postconcussional Disorder and whether and how it should be assessed under Chapter 7 of the MAA Guidelines.

Points to note

  1. There is medical controversy about the status of the condition. Furthermore as Prigatano and Gale write "There is a striking discrepancy between the presumably 'subjective' complaints of the patient and the presumably ‘objective’ findings of the physician. This almost inevitably leads to an uncomfortable state of cognitive dissonance in both parties and sometimes to open conflict between them."
  2. While typically after a concussive injury there is a rapid improvement in symptomatology and a return to normal functioning, approximately 10% of the concussed population present with persistent PCS. These individuals tend to be older and have a history of extra cranial injuries, often involving pain. Those individuals who show intense emotional reactions at the time of the injury and heightened symptoms are at risk of developing persistent PCS. Co-morbid psychiatric disorder in this population is also high.
  3. In relation to an organic brain jury, although clause 7.12 of the MAA Guidelines states that: "Mental and behavioural disorders resulting from organic brain injury are most suitably assessed as an organic problem under the Nervous Symptom Impairment Chapter of these MAA Guidelines (Chapter 5)", this does not restrict the assessment of organic brain injuries to only a physical assessment of permanent impairment. That is, where appropriate and indicated, organic brain injury may and should be assessed on the grounds of its impact on mental and behavioural function in accordance with Chapter 7 of the MAA Guidelines.
  4. Clause 7.13 of the MAA Guidelines states: "The impairment must be attributable to a recognised psychiatric diagnosis in accordance with...[DSM-IV], ...[ICD 10] or a substantial body of peer review research literature. The impairment evaluation report must specify the diagnostic criteria upon which the diagnosis is based".
  5. Postconcussional Disorder is included in the Appendix of DSM-IV which suggests that Postconcussional Disorder is not yet a recognised diagnosis. However, Postconcussional Disorder could be included in DSM-IV under "Cognitive Disorder NOS".

Postconcussional Syndrome is included in ICD 10 in the category "Personality and behavioural disorders due to brain disease, damage and dysfunction". It is not classified in ICD 10 as a somatoform disorder.

Preferred approach

Because this is an uncertain and controversial area Assessors should ensure that they are up to date with current research if they are considering making a diagnosis of Postconcussional Syndrome.

Assessors should consider whether there is another psychiatric disorder which could better account for the person’s symptoms. As in all cases, the Assessor should also consider whether there was a pre-existing psychiatric disorder which could be contributing to the person’s current presentation and impairment.

At the time this Guidance Note was prepared, it is recommended that, if there is not a more appropriate psychiatric disorder, then a diagnosis of Postconcussional Syndrome (using ICD 10 criteria) can be made providing that the diagnostic criteria are demonstrated to apply. Impairment can be then assessed in the usual way taking into account issues such as causation, pre-existing and subsequent injuries and consistency.

As for all the assessments of psychiatric disorders, assessors must be trained in the application of the relevant Chapter of the AMA 4 and the MAA PI Guidelines (refer to Chapter 7 Mental and Behavioural Disorders Impairment, clause 7.17 page 39). It is expected that a diagnosis of Postconcussional Syndrome will only be made by a psychiatrist.

Justification for preferred interpretation

The preferred interpretation and methodology is suggested to promote consistency of assessment.


Issued by:

Injury Strategy Branch

August 2012