FOUR Score — Coma Assessment Scale
The FOUR (Full Outline of UnResponsiveness) Score is a coma scale developed as an alternative to the Glasgow Coma Scale (GCS), with advantages in intubated patients and those with severe brain injury.
About
The FOUR Score evaluates four domains: Eye response (0-4), Motor response (0-4), Brainstem reflexes (0-4), and Respiration (0-4). Total score ranges from 0-16. It provides more neurological detail than GCS, including brainstem function and respiratory patterns, making it particularly useful in the ICU setting.
Formula
FOUR = Eye + Motor + Brainstem + Respiration (0-4 each)
The FOUR Score is calculated by summing the scores of its four components, each scored 0-4. Eye response assesses whether eyes open spontaneously and track the examiner's finger (4), open but do not track (3), open to loud voice (2), open to pain (1), or remain closed with no response (0). Motor response evaluates upper limb function: the patient can make a thumbs-up or fist (4), localizes to pain (3), flexion response to pain (2), extension response to pain (1), or no response (0). Brainstem reflexes assess pupillary light reflex and corneal reflex: both pupil and corneal reflexes present (4), one pupil wide and fixed with corneal reflex present (3), one pupil or one corneal reflex present (2), one of the two reflexes present (1), or both absent (0). Respiration evaluates breathing pattern: regular breathing (4), Cheyne-Stokes respiration (3), irregular breathing (2), mechanically ventilated with triggered breaths (1), or apnea or ventilator-driven respirations (0). The total score ranges from 0 (deep coma/no brainstem function) to 16 (fully conscious with normal brainstem function and respiration). The FOUR Score avoids the verbal component limitation of GCS in intubated patients and incorporates brainstem function assessment, which is critical for prognostication.
Score Interpretation
The FOUR (Full Outline of UnResponsiveness) Score was developed by Dr. Eelco Wijdicks and colleagues at the Mayo Clinic, first published in Neurology in 2005. It was designed to address several limitations of the Glasgow Coma Scale (GCS). First, the FOUR Score eliminates the verbal component, which cannot be assessed in intubated patients — a significant limitation of GCS in ICU settings where up to 40-60% of patients are intubated. Second, it incorporates brainstem reflex assessment (pupillary light reflex and corneal reflex), providing critical neurological information that GCS omits. Brainstem function is one of the strongest predictors of outcome after severe brain injury. Third, the FOUR Score includes respiratory pattern assessment, capturing important clinical information about brainstem respiratory centers. Fourth, the motor component is tested in the upper limbs only, avoiding the confounding effect of lower extremity spinal cord injury. The FOUR Score has been validated across multiple clinical settings including traumatic brain injury, intracerebral hemorrhage, subarachnoid hemorrhage, cardiac arrest, and general neurocritical care populations. Studies have demonstrated excellent inter-rater reliability, with weighted kappa values exceeding 0.80 across all four components. The FOUR Score has also shown comparable or superior prognostic accuracy to GCS for predicting mortality and poor functional outcomes after severe brain injury. A score of 0 on the FOUR Score (all four components absent) is a critical finding that, in the absence of sedative medications, raises concern for brain death and should prompt formal brain death evaluation. Major neurocritical care societies, including the Neurocritical Care Society (NCS), recognize the FOUR Score as a valuable complement to GCS in the ICU setting.
Severe Brain Injury — 0–4
FOUR Score 0-4 indicates severe brain injury with high mortality. Patient has minimal or no brainstem function and requires aggressive neuroprotective management.
Management: Consider neuroprotective measures, ICP monitoring, and urgent neurosurgery consultation. High mortality expected.
Moderate to Severe Brain Injury — 5–8
FOUR Score 5-8 indicates moderate to severe brain injury. Significant neurological impairment with some brainstem function preserved.
Management: Continue close neurological monitoring, consider imaging and EEG monitoring as indicated. Neurosurgery consultation advised.
Mild to Moderate Brain Injury — 9–12
FOUR Score 9-12 indicates mild to moderate brain injury. Patient has meaningful neurological responses with intact brainstem function.
Management: Routine neurological monitoring. Observe for any deterioration. May be appropriate for step-down unit.
Mild / Normal — 13–16
FOUR Score 13-16 indicates mild or no significant neurological injury. Good prognosis expected with intact brainstem function and spontaneous breathing.
Management: No acute neurological intervention required unless other clinical findings suggest otherwise. Good prognosis expected.
Reference Ranges
| Population | Normal Range | Notes |
|---|---|---|
| Neurocritical care patients (coma assessment) | 13 – 16 | Mild/no neurological injury. Good prognosis. |
Dr. Mahmoud El-Sayed
Dr. Mahmoud El-Sayed is a consultant neurologist with over 15 years of experience in clinical neurology, neurocritical care, and stroke medicine.
View medical review board & editorial policy →Example Calculation
A 55-year-old male is admitted to the ICU following a massive intracerebral hemorrhage. On neurological examination, his eyes are closed and do not open to verbal stimulation but open briefly to painful nail bed pressure — he does not track the examiner's finger (Eye = 1). Motor examination shows the patient extends his arms to painful stimulation (decerebrate posturing) — no localization or withdrawal (Motor = 1). Pupillary examination reveals both pupils are 4 mm and sluggishly reactive to light; the corneal reflex is absent bilaterally — only one reflex (pupillary) is partially present (Brainstem = 1). The patient is on mechanical ventilation with no spontaneous respiratory efforts above the set rate (Respiration = 0). Total FOUR Score = 1 + 1 + 1 + 0 = 3/16. This indicates severe brain injury with extremely high mortality risk. The patient requires neuroprotective measures including head-of-bed elevation, avoidance of hyperthermia and hyperglycemia, and ICP monitoring. Given the brainstem involvement and poor neurological exam, discussions regarding goals of care and prognosis should be initiated with the family.
Related Conditions
Related Medications
Common Mistakes
Confusing FOUR Score motor component with GCS motor scale
FOUR Score motor response is assessed in the upper limbs only (0-4), while GCS motor is assessed in the best limb (1-6). FOUR tests specific hand commands (thumbs up/fist) rather than general command-following. Do not attempt to convert between the two scales.
Scoring brainstem reflexes in patients under sedation
Sedative medications can suppress pupillary and corneal reflexes. Document any sedative use and, when possible, assess brainstem reflexes during sedation holidays or at trough levels. A FOUR Score of 0 on brainstem reflexes may be drug-induced rather than indicating brain death.
Frequently Asked Questions
How is the FOUR Score different from GCS?
What does a FOUR Score of 0 indicate?
References
- Wijdicks EFM, Bamlet WR, Maramattom BV, et al. Validation of a new coma scale: The FOUR score. Ann Neurol. 2005;58(4):585-593. PubMed
- Stead LG, Wijdicks EFM, Bhagra A, et al. Validation of a new coma scale: the FOUR score in the emergency department. Neurocrit Care. 2009;10(1):50-54. PubMed
- Bruno MA, Ledoux D, Lambermont B, et al. Comparison of the Full Outline of UnResponsiveness and Glasgow Liege Scale/Glasgow Coma Scale in an intensive care unit population. Neurocrit Care. 2011;15(3):447-453. PubMed