An operational definition of concussion

During the development of this operational definition of concussion it was agreed that this definition should address the timing of concussion assessment(s), how the diagnosis of concussion is confirmed or excluded and the content of each point-in-time assessment.

Timing of the assessment

World Rugby has introduced a three-stage diagnostic process. This incorporates:

1. An assessment immediately post injury (HIA 1);

2. Repeat assessment within 3 h of the injury (HIA 2);

3. Follow-up assessment at 36–48 h post injury (HIA 3).

This three-stage process was introduced recognising that concussion has a variable natural history, with transient, fluctuating, delayed and evolving signs or symptoms. In addition, the diagnostic process also aligns with the times that the team doctor's normal responsibilities involve team contact.

Diagnosis, confirmation or exclusion

World Rugby's operational definition assumes that any abnormal assessment confirms a concussion diagnosis unless the treating doctors provides clinical confirmation that the abnormal findings are not related to a concussion. In addition, exclusion of a concussion following a head injury cannot occur immediately after the injury but can only be confirmed after re-evaluation of the player at 36–48 h post injury.

World Rugby's operational definition a concussion applies with any of the following:

1. The presence, pitch side, of any Criteria Set 1 signs or symptoms (table 1)—HIA 1;

2. An abnormal post game, same day assessment—HIA 2;

3. An abnormal 36–48 h assessment—HIA 3;

4. The presence of clinical suspicion by the treating doctor at any time.

What does the assessment consist of?

The content of all three World Rugby's HIA tools is based on the SCAT34 and is available with the procedures on http://playerwelfare.worldrugby.org/concussion. It is acknowledged that the content of HIA tools will continue to be modified as the evidence around concussion diagnosis evolves.

World Rugby's HIA 1, contains Criteria Set 1 (table 1) which are indications for immediate and permanent removal from further game participation. The presence of any Criteria Set 1 confirms a concussion, unless proven otherwise. The HIA 1 also contains a 10 min off-field assessment tool used when a player has a head injury where the diagnosis is not immediately apparent.

A key fact of the World Rugby off-field assessment is that it has been designed to screen for cases of suspected concussion. This off-field assessment was not developed with the intention of diagnosing a concussion.

HIA 2, completed within 3 hours of the injury, is SCAT 3 without the Glasgow Coma Scale and the Maddocks’ Questions and includes relevant athlete and injury information.

HIA 3, completed within 36–48 h of the injury includes:

1. Symptom checklist as per SCAT 3 with collection of all symptoms experienced since the head injury, symptom duration and maximum symptom severity;

2. Cognitive assessment of that team's choice using the computer neurocognitive assessment tool of that team's choice and/or the SAC component of SCAT 3

3. Balance evaluation using Modified Balance Error Scoring System and tandem gait.

Summary

World Rugby has introduced an operational definition of concussion into Rugby to better identify and manage concussion and to support injury surveillance studies. This definition acknowledges the variability in clinical concussion presentation by incorporating a three-point in time diagnostic process with the recommended times aligning with the times that team doctor's normal responsibilities involve team contact.

The current content of each assessment is based on SCAT 3 and will continue to be modified as the evidence around concussion diagnosis evolves.

This operational definition of concussion also includes the recommendation that any abnormal assessment be considered as being due to concussion. This default can be over-ruled if the team doctor decides that the abnormal assessment is not related to a concussion. Finally with World Rugby's operational definition, a concussion following a head injury cannot be excluded until an assessment is completed at 36–48 h post injury.