Clinical Overview
The Glasgow Coma Scale provides a reproducible description of a patient’s observable eye, verbal, and motor responses. It was developed for impaired consciousness and remains widely used in trauma, emergency medicine, neurology, critical care, and prehospital communication. The separate components preserve more clinical information than the total score: two patients with the same total may have very different patterns of neurologic dysfunction.
Assess the patient after immediate threats to airway, breathing, and circulation have been addressed. Use a clear stimulus sequence, progressing from spoken request to appropriate peripheral pressure only when needed. Record the best observed response in each component along with the time, relevant confounders, and whether the response was not testable. Serial change—especially a fall in motor response or total score—can matter more than one isolated value.
When to Use
- Initial and serial assessment of impaired consciousness
- Traumatic brain injury communication and triage
- Monitoring neurologic change after acute illness, sedation, or intervention
Limitations & Safety
Intubation prevents a standard verbal response; sedation, neuromuscular blockade, aphasia, deafness, language difference, orbital swelling, spinal cord injury, and limb trauma can also confound testing. Do not assign an arbitrary score of one simply because a component is untestable. Document the reason, such as V-NT for an endotracheal tube, according to local charting practice, and communicate the actual components.
The traditional total is commonly grouped as severe (3–8), moderate (9–12), and mild (13–15) impairment, but these bands are descriptive rather than stand-alone treatment thresholds. A GCS of 8 or less often accompanies consideration of airway protection, yet airway decisions require evaluation of protective reflexes, ventilation, oxygenation, trajectory, intoxication, seizures, and anticipated transfer. Pediatric patients require age-appropriate verbal and motor descriptors.
- Components may be untestable with intubation, severe facial injury, paralysis, language barrier, or sedation
- Do not collapse components into a total without documenting E, V, and M
- Not a substitute for pupillary, brainstem, focal neurologic, or airway assessment
Formula / Scoring Criteria
GCS = Eye response (1–4) + Verbal response (1–5) + Motor response (1–6); total 3–15
Interpretation
- 13–15 — Mild or no global impairment: Important focal or evolving pathology may still be present. Document components, investigate the cause, and repeat after any change.
- 9–12 — Moderate impairment: Meaningful reduction in consciousness with risk of deterioration. Close monitoring, address reversible causes, and obtain urgent clinical review.
- 3–8 — Severe impairment: High risk of airway compromise and serious neurologic injury. Immediate ABC assessment, senior support, and definitive neurologic evaluation.
Evidence & References
- Teasdale G, Jennett B. Assessment of coma and impaired consciousness. Lancet. 1974.
- Teasdale G, et al. The Glasgow Coma Scale at 40 years. Lancet Neurol. 2014.
- NICE guideline NG232: Head injury assessment and early management.
Clinical FAQs
How should an intubated patient be scored?
Report eye and motor responses and mark verbal as not testable because of the tube. Avoid presenting a misleading standard total without the qualifier.
Is the painful stimulus sternal rub recommended?
A standardized peripheral pressure stimulus is generally preferred for motor assessment. Follow local training and avoid techniques that cause bruising or cannot distinguish localization from flexion.
Does GCS 15 exclude brain injury?
No. Concussion, intracranial bleeding, focal deficit, and evolving injury can occur with GCS 15. Apply the complete history, examination, and imaging decision rules.