The Glasgow Coma Scale (GCS) is a standardized, rapid assessment tool used by healthcare professionals worldwide to determine a patient’s level of consciousness. Developed in 1974, the scale reliably communicates the severity of a patient’s neurological condition, especially following a traumatic brain injury. Learning the GCS requires memorizing three distinct categories of response and the specific criteria for scoring each one. This method provides a common language for medical teams and helps guide immediate management decisions in acute care settings.
Understanding the Three Categories
The GCS is structured around three components: Eye opening (E), Verbal response (V), and Motor response (M). The mnemonic EVM helps recall these categories in order. Each category is assigned a score, and these scores are summed to give the total GCS score, ranging from 3 to 15. The maximum score for each component is different: Eye response is scored out of four points (E4), Verbal out of five points (V5), and Motor out of six points (M6). The minimum score for every category is always one, meaning a patient exhibiting no response will still have a GCS score of 3 (E1 + V1 + M1).
Mnemonics for Sub-Score Criteria
Eye Response (E4)
The Eye Response (E4) has four possible scores, descending from the best response (4) to the worst (1). The scores are associated with the stimulus required to achieve the response.
- 4: Eyes open spontaneously.
- 3: Eyes open in response to a verbal command.
- 2: Eyes open only in response to pain.
- 1: No eye opening, even following a painful stimulus.
Verbal Response (V5)
The Verbal Response (V5) has five levels, memorized by focusing on the descending quality of the patient’s speech.
- 5: Oriented, converses appropriately, knowing name, location, and date.
- 4: Confused, speaking in sentences but disoriented and unable to answer questions correctly.
- 3: Inappropriate Words, speaking recognizable but random words that make no conversational sense.
- 2: Incomprehensible Sounds, including moaning or grunting without forming recognizable words.
- 1: No Verbal Response, even after painful stimulation.
Motor Response (M6)
The Motor Response (M6) has six levels and is considered the most reliable indicator of neurological status. The mnemonic focuses on the action verbs associated with each level.
- 6: Obeys Commands, such as wiggling toes or squeezing a hand.
- 5: Localizes to Pain, attempting to move the limb or hand to push the painful stimulus away.
- 4: Withdrawal to Pain, pulling the limb away from the stimulus.
- 3: Abnormal Flexion (decorticate posturing).
- 2: Abnormal Extension (decerebrate posturing).
- 1: No Motor Response to pain.
Applying the Total Score
The total GCS score (3 to 15) is used to classify the severity of a patient’s brain injury, influencing treatment and prognosis. Medical professionals use three accepted thresholds for rapid clinical decision-making.
Traumatic Brain Injury Classification
A score between 13 and 15 indicates a Mild Traumatic Brain Injury (TBI). A score ranging from 9 to 12 is classified as a Moderate TBI. The most clinically significant range is a score of 8 or less, which defines a Severe TBI.
The “Eight, Intubate” Mnemonic
The clinical mnemonic “Eight, Intubate” focuses on the critical threshold of 8. This score links directly to the immediate medical action of securing the patient’s airway. A patient with a GCS of 8 or below is generally considered to have lost the protective reflexes necessary to maintain an open airway.