How it's calculated
Four components — eye, motor, brainstem reflexes, and respiration — are each scored 0-4 and summed for a total of 0-16. Unlike GCS, no component depends on verbal response, so it can be scored fully in intubated or aphasic patients.
Scoring detail
| Score | Eye | Motor | Brainstem | Respiration |
|---|---|---|---|---|
| 4 | Eyelids open/tracking or blinking to command | Thumbs-up, fist, or peace sign | Pupil & corneal reflexes present | Not intubated, regular pattern |
| 3 | Eyelids open, not tracking | Localises to pain | One pupil wide and fixed | Not intubated, Cheyne-Stokes pattern |
| 2 | Eyelids closed, opens to loud voice | Flexion response to pain | Pupil OR corneal reflex absent | Not intubated, irregular pattern |
| 1 | Eyelids closed, opens to pain | Extension response to pain | Pupil AND corneal reflexes absent | Breathes above ventilator rate |
| 0 | Eyelids remain closed with pain | No response to pain, or myoclonus status | Absent pupil, corneal, and cough reflex | Breathes at ventilator rate, or apnoea |
Clinical use
- Developed as an alternative to GCS that can be fully scored in intubated, sedated, or aphasic patients, since none of its 4 components require verbal response.
- Can identify a locked-in state (eyes tracking normally but no motor response) that GCS would score as deep coma, since GCS's best possible score in an intubated patient is capped by the missing verbal component.
- Explicitly assesses brainstem reflexes, which GCS does not evaluate at all.
Frequently asked questions
What does FOUR Score stand for?
Full Outline of UnResponsiveness — a 4-component coma scale (Eye, Motor, Brainstem, Respiration) developed as an alternative to GCS, particularly for intubated or aphasic patients.
Why use FOUR Score instead of GCS?
GCS's verbal component can't be scored in an intubated patient, capping the achievable score. FOUR Score has no verbal component, adds an assessment of brainstem reflexes, and can distinguish a locked-in state from true coma.
What is the range of the FOUR Score?
0 to 16, with each of the 4 components scored 0-4. Lower totals indicate deeper unresponsiveness, similar in direction to GCS (where lower is also worse).
References
- Wijdicks EF, et al. Validation of a new coma scale: The FOUR score. Ann Neurol. 2005;58:585-593.
- Wijdicks EF, et al. Comparison of the Full Outline of UnResponsiveness score and the Glasgow Coma Scale in predicting mortality in critically ill patients. Crit Care Med. 2015;43:439-444.