Full Outline Of UnResponsiveness (FOUR) Score

The scoring method explained

This is a neurological grading scale that helps clinicians evaluate patients with impaired level of consciousness. FOUR comes from "Full Outline of UnResponsiveness".

The score addresses four domains of neurological functioning, each being described by a series of items that are awarded different weights (in points).

The FOUR assessment bypasses two major shortcomings of the Glasgow Coma Scale, the other clinical grading scale of this kind:

■ GCS cannot be used on patients with endotracheal intubation;

■ The GCS does not check brainstem response.

This neurological tool can help detect subtle changes in the neurological examination, especially in cases of traumatic head injury.

The following table introduces the four neurological domains that are evaluated by this score:

*Myoclonus status is characterized by persistent, multisegmental, ar-rhythmic, jerklike movements.

Result interpretation

Each of the 4 domains of neurological function is awarded a number of points, depending on the selected answer. The sum of these points makes up the final FOUR score.

The minimum obtainable is 0 while the maximum score is 16, where the lower the score, the greater the coma gravity.

The score has been compared to other ER grading systems, such as the AVPU or the GCS.

The comparison of the inter-observer reliability of the FOUR model and the GCS revealed that the former performed better. The FOUR assessment also has better biostatistical properties (sensitivity, specificity, accuracy and positive predictive value) than the GCS.

About the study

The FOUR neurological assessment was created by Wijdicks et al. in 2005 and was aimed at addressing evaluation shortcomings of Glasgow Coma Scale in intubated patients.

The score was tested on 120 ICU patients and compared to the GCS. Interrater reliability was excellent (kappa(w) = 0.82). It was also found that patients with low GCS scores would benefit from the FOUR assessment because of its superiority in evaluating brainstem reflexes and breathing patterns.

Impaired level of consciousness

All disturbances of consciousness close to coma and caused by a dysfunction present in the cerebral hemispheres or in the reticular activating system are classified as impaired consciousness. The following stratifies the levels of impaired consciousness:

■ Confusion (lack of clear thinking);

■ Disorientation (inability to recognize places, objects or other inaccuracies);

■ Delirium (confusion and lack of logic thinking);

■ Lethargy (decreased consciousness status);

■ Stupor (deepest level before coma, partial lack of response to stimuli);

■ Coma.

Original source

Wijdicks EF, Bamlet WR, Maramattom BV, Manno EM, McClelland RL. Validation of a new coma scale: The FOUR score. Ann Neurol. 2005; 58(4):585-93.

Other references

1. Wolf CA, Wijdicks EF, Bamlet WR, McClelland RL. Further validation of the FOUR score coma scale by intensive care nurses. Mayo Clin Proc. 2007; 82(4):435-8.

2. Iyer VN, Mandrekar JN, Danielson RD, Zubkov AY, Elmer JL, Wijdicks EF. Validity of the FOUR score coma scale in the medical intensive care unit. Mayo Clin Proc. 2009; 84(8):694-701.

3. Stead LG, Wijdicks EF, Bhagra A, Kashyap R, Bellolio MF, Nash DL, Enduri S, Schears R, William B. Validation of a new coma scale, the FOUR score, in the emergency department. Neurocrit Care. 2009; 10(1):50-4.

4. Fischer M, Rüegg S, Czaplinski A et al. Inter-rater reliability of the Full Outline of UnResponsiveness score and the Glasgow Coma Scale in critically ill patients: a prospective observational study. Crit Care. 2010; 14(2):R64.