Glasgow Coma Scale Assessment
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Direct answer
The Glasgow Coma Scale (GCS) is the standard bedside tool for assessing and monitoring the level of consciousness by scoring three responses — eye opening (4), verbal response (5) and motor response (6) — for a maximum of 15 and a minimum of 3. It is scored by observing spontaneous behaviour first, then speaking to the patient, and finally applying a standardised painful stimulus if needed, always recording the best response from each side. Scores of 13-15 indicate mild brain injury, 9-12 moderate and 8 or below severe — the level at which airway protection is compromised and intubation is considered.
What you must remember
- Eye opening (E): 4 spontaneous, 3 to speech, 2 to pain, 1 none.
- Verbal response (V): 5 oriented, 4 confused conversation, 3 inappropriate words, 2 incomprehensible sounds, 1 none.
- Motor response (M): 6 obeys commands, 5 localises pain, 4 withdraws from pain, 3 abnormal flexion (decorticate), 2 abnormal extension (decerebrate), 1 none.
- Record components separately (for example E3 V4 M5 = 12) and never as a total alone; a total of 12 can hide very different pictures.
- Severity bands: 13-15 mild, 9-12 moderate, 3-8 severe; the classic maxim "GCS 8 or below, intubate" reflects loss of airway protection.
- Use a standardised painful stimulus such as supraorbital pressure or trapezius squeeze, applied centrally; note the best motor response, and check both sides to detect a focal deficit.
- Non-testable components are documented as such (for example, V-not testable in an intubated patient, E not testable with orbital swelling); the paediatric version modifies verbal and motor items for infants.
Common confusion
Two scoring errors recur in exams. First, abnormal flexion versus extension: decorticate rigidity (arms flexed, legs extended) scores M3, while decerebrate extension (all limbs extended) scores M2 and indicates deeper brainstem involvement. Second, scoring the worst instead of the best response — the rule is always the best response observed, using the unaffected side in a weak patient.
Exam-focused takeaway
Every nursing paper carries at least one GCS item: matching a described patient to a score, computing totals from given components, or stating the severity bands. Be ready to write the full table from memory, to state what each component's maximum is, and to explain why trends matter more than one reading — a two-point fall is a danger signal to report. The intubation threshold of 8 and the paediatric modifications are favourite MCQs.
Frequently asked questions
How is the GCS performed at the bedside?
Observe for spontaneous eye opening and speech; if absent, call the patient loudly, then apply a standardised central painful stimulus such as supraorbital pressure. The best eye, verbal and motor responses are charted and compared with previous readings.
What do decorticate and decerebrate posturing mean?
Decorticate (abnormal flexion, M3) shows arms bent inward with extended legs; decerebrate (abnormal extension, M2) shows all limbs rigidly extended, indicating deeper brainstem injury.
Why record component scores and not just the total?
The same total can arise from different combinations, and a falling motor score with a stable total still signals deterioration. Components stay meaningful when one part is untestable, such as the verbal score of an intubated patient.
What is the significance of GCS 8 or below?
Protective airway reflexes and ventilation are usually inadequate, so the patient generally needs intubation. The score is reported to the physician immediately.
What are the limitations of the GCS?
It cannot be fully applied to intubated, sedated or intoxicated patients and cannot detect focal deficits alone, so pupils, vital signs and limb strength complete the picture.