2 Level of Consciousness and Glasgow Coma Scale

Level of consciousness

A quick impression such as “sleepy” or “alert” can be useful, but the Glasgow Coma Scale (GCS) provides a structured way to describe observed responses. It assesses eye opening, verbal response, and motor response.

How to score the GCS

Assess spontaneous behavior first. If needed, use verbal and then physical stimuli according to clinical training and local protocol. Score the best observed response in each component.

Eye opening

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Adding and interpreting scores

Add the eye opening, verbal response, and motor response scores to obtain a total from $3$ to $15$, provided all components are testable. For example, $\mathrm{E}=3,\ \mathrm{V}=4,\ \mathrm{M}=6$ gives a total of $13$.

In head-injury classifications, totals from $13$ to $15$ are commonly called mild, totals from $9$ to $12$ moderate, and totals of $8$ or less severe. These categories do not replace a full clinical assessment.

Why component scores matter

Record the $\mathrm{E}$, $\mathrm{V}$, and $\mathrm{M}$ scores separately as well as their sum. A total can conceal different response patterns, while the component scores show which observed responses account for a change.

For example, if a person’s scores change from $\mathrm{E}=4,\ \mathrm{V}=5,\ \mathrm{M}=6$ to $\mathrm{E}=3,\ \mathrm{V}=4,\ \mathrm{M}=6$, eye opening decreases from $4$ to $3$, verbal response decreases from $5$ to $4$, and motor response remains $6$. Comparing the components makes those changes visible when a total alone would provide less detail.

When assessment is limited

If a component cannot be assessed, record it as not testable (NT) and document the reason. For example, if a person is intubated and cannot speak, do not automatically score the verbal response as $1$. An untestable response is not the same observation as no verbal response, and NT should not be treated as a numeric $1$ when calculating a total.

Factors that may make components difficult to assess or interpret reliably include intubation, sedation, language or hearing barriers, speech impairment or aphasia, facial injury affecting speech, swelling affecting eye opening, and motor impairment. These factors can interfere with particular components or with interpretation of the total.

Applying the scoring scales

Use the component scales to identify each response and score:

• Eyes open spontaneously: eye opening, $4$.

• Gives confused conversation: verbal response, $4$.

• Makes sounds that are not words: verbal response, $2$.

• Obeys a command to move a limb: motor response, $6$.

• Extends the limbs in response to pressure: motor response, $2$.

For a person who opens their eyes to sound, speaks in confused conversation, and obeys commands, record $\mathrm{E}=3,\ \mathrm{V}=4,\ \mathrm{M}=6$; the total is $13$. For responses of $\mathrm{E}=2,\ \mathrm{V}=2,\ \mathrm{M}=4$, the total is $2+2+4=8$, in the commonly used severe head-injury category. Interpret the result in the full clinical context.

Using the GCS appropriately

The GCS describes responsiveness through eye opening, verbal response, and motor response, assessed separately and summed when all components are testable. Record the components, not just the total, and note factors that limit assessment. A GCS score is a structured description of observed responses, not a complete neurological examination.