Glasgow Coma Scale
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Direct answer
The Glasgow Coma Scale, described by Teasdale and Jennett, grades conscious level by three responses — eye opening (maximum 4), verbal (maximum 5) and motor (maximum 6) — for a total of 3 to 15. A score of 13-15 indicates mild, 9-12 moderate and 8 or less severe brain injury. It is charted serially using the best response, and a total of 8 or below is the traditional threshold for protecting the airway by intubation.
What you must remember
- Eye opening — 4 spontaneous, 3 to speech, 2 to pain, 1 none.
- Verbal — 5 oriented, 4 confused, 3 inappropriate words, 2 incomprehensible sounds, 1 none.
- Motor — 6 obeys commands, 5 localises pain, 4 withdraws, 3 abnormal flexion (decorticate), 2 abnormal extension (decerebrate), 1 none.
- The motor response carries the strongest prognostic weight; always chart the components (for example E3 V4 M5) rather than the sum alone.
- In intubated or sedated patients record the score with a qualifier such as V1t, and use the paediatric modification for infants and small children.
- The scale complements, never replaces, pupil examination and limb deficit assessment; a fall of two or more points is an emergency demanding immediate reassessment and CT.
- Score the best response from the best side, avoid testing a fractured limb, and apply standard painful stimuli such as nail-bed pressure or trapezius squeeze.
Common confusion
Decorticate and decerebrate posturing are endlessly swapped. Abnormal flexion (motor 3) is a decorticate pattern seen with lesions above the midbrain, while abnormal extension (motor 2) is a decerebrate pattern reflecting more caudal midbrain or brainstem involvement and scores lower. Another favourite trap: the minimum GCS is 3, not 0 — even a completely unresponsive patient scores 3. And remember the sum "E1 V1 M1 = 3" is the floor of the scale.
Exam-focused takeaway
Scoring arithmetic is guaranteed — a vignette gives responses and asks the total or the missing component. Know the severity bands (13-15, 9-12, 8 or less), the "GCS 8, intubate" rule, and the motor hierarchy from obeys to none. The most prognostic component (motor) and the documentation format for intubated patients are frequent single-best-answer stems.
Frequently asked questions
What are the three components and their maxima?
Eye opening out of 4, verbal response out of 5 and motor response out of 6, giving a maximum of 15 and a minimum of 3.
What score defines severe head injury?
A GCS of 8 or less after resuscitation defines severe injury and is the traditional trigger for intubation to protect the airway.
Why record component scores and not just the total?
Components convey more information — a patient can be intubated (V1t) or have a fixed eye from swelling. Trends in components localise deterioration better than a single total.
How is the scale used in sedated or intubated patients?
The verbal score cannot be tested, so it is qualified (Vt) and the recorded score interpreted with sedation status. Serial motor and eye scoring remains valuable.
Which component best predicts outcome?
The motor response. It has the strongest correlation with survival and recovery and anchors prognostic models alongside pupil reactivity and age.