Glasgow Coma Scale (GCS) Explained
How clinicians measure consciousness after brain injury.
The Glasgow Coma Scale (GCS) is the most widely used tool for assessing a person's level of consciousness after a brain injury. Developed in 1974, it evaluates three domains: eye opening, verbal response, and motor response. The total score ranges from 3 (deep coma) to 15 (fully awake).
Eye Opening (E): 1 to 4
| Score | Response |
|---|---|
| 4 | Spontaneous |
| 3 | To speech |
| 2 | To pain |
| 1 | No response |
Verbal Response (V): 1 to 5
| Score | Response |
|---|---|
| 5 | Oriented |
| 4 | Confused |
| 3 | Inappropriate words |
| 2 | Incomprehensible sounds |
| 1 | No response |
Motor Response (M): 1 to 6
| Score | Response |
|---|---|
| 6 | Obeys commands |
| 5 | Localizes pain |
| 4 | Withdraws from pain |
| 3 | Flexion (decorticate) |
| 2 | Extension (decerebrate) |
| 1 | No response |
Interpreting the Total Score
- 13–15: Mild brain injury
- 9–12: Moderate brain injury
- 3–8: Severe brain injury (coma)
Limitations
The GCS cannot be used in patients with severe facial swelling, intubation, or pre-existing language barriers. In these cases, clinicians often report a modified score (e.g., GCS 10T, where "T" means intubated).
Practice GCS scoring with our interactive GCS calculator.
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Medical Disclaimer: This article is for educational purposes only and does not replace professional medical advice.