What Is the Glasgow Coma Scale?

Editor’s Note: This article was originally published at Brainline.org, and is republished here with permission.

The Glasgow Coma Scale (GCS) is the most common scoring system used to describe the level of consciousness in a person following a traumatic brain injury. Basically, it is used to help gauge the severity of an acute brain injury. The test is simple, reliable, and correlates well with outcome following severe brain injury.

The GCS is a reliable and objective way of recording the initial and subsequent level of consciousness in a person after a brain injury. It is used by trained staff at the site of an injury like a car crash or sports injury, for example, and in the emergency department and intensive care units.

The GCS measures the following functions:

Eye Opening (E)

  • 4 = spontaneous

  • 3 = to sound

  • 2 = to pressure

  • 1 = none

  • NT = not testable

Verbal Response (V)

  • 5 = orientated

  • 4 = confused

  • 3 = words, but not coherent

  • 2 = sounds, but no words

  • 1 = none

  • NT = not testable

Motor Response (M)

  • 6 = obeys command

  • 5 = localizing

  • 4 = normal flexion

  • 3 = abnormal flexion

  • 2 = extension

  • 1 = none

  • NT = not testable

Clinicians use this scale to rate the best eye opening response, the best verbal response, and the best motor response an individual makes. The final GCS score or grade is the sum of these numbers.

Using the Glasgow Coma Scale

A patient's Glasgow Coma Score (GCS) should be documented on a coma scale chart. This allows for improvement or deterioration in a patient's condition to be quickly and clearly communicated.

Individual elements, as well as the sum of the score, are important. The individual elements of a patient's GCS can be documented numerically (e.g. E2V4M6) as well as added together to give a total Coma Score (e.g E2V4M6 = 12). For example, a score may be expressed as GCS 12 = E2 V4 M6 at 4:32.

Every brain injury is different, but generally, brain injury is classified as:

  • Severe: GCS 8 or less

  • Moderate: GCS 9-12

  • Mild: GCS 13-15

Mild brain injuries can result in temporary or permanent neurological symptoms and neuroimaging tests such as CT scan or MRI may or may not show evidence of any damage.

Moderate and severe brain injuries often result in long-term impairments in cognition(thinking skills), physical skills, and/or emotional/behavioral functioning.

Limitations of the Glasgow Coma Scale

Factors like drug use, alcohol intoxication, shock, or low blood oxygen can alter a patient’s level of consciousness. These factors could lead to an inaccurate score on the GCS.

Children and the Glasgow Coma Scale

The GCS is usually not used with children, especially those too young to have reliable language skills. The Pediatric Glasgow Coma Scale, or PGCS, a modification of the scale used on adults, is used instead. The PGCS still uses the three tests — eye, verbal, and motor responses — and the three values are considered separately as well as together.

Here is the slightly altered grading scale for the PGCS:

Eye Opening (E)

  • 4 = spontaneous

  • 3 = to voice

  • 2 = to pressure

  • 1 = none

  • NT = not testable

Verbal Response (V)

  • 5 = smiles, oriented to sounds, follows objects, interacts

  • 4 = cries but consolable, inappropriate interactions

  • 3 = inconsistently inconsolable, moaning

  • 2 = inconsolable, agitated

  • 1 = none

  • NT = not testable

Motor Response (M)

  • 6 = moves spontaneously or purposefully

  • 5 = localizing (withdraws from touch)

  • 4 = normal flexion (withdraws to pain)

  • 3 = abnormal flexion (decorticate response)

  • 2 = extension (decerebrate response)

  • 1 = none

  • NT = not testable

Pediatric brain injuries are classified by severity using the same scoring levels as adults, i.e. 8 or lower reflecting the most severe, 9-12 being a moderate injury and 13-15 indicating a mild TBI. As in adults, moderate and severe injuries often result in significant long-term impairments.

 

References

Teasdale G, Allen D, Brennan P, McElhinney E, Mackinnon L. The Glasgow Coma Scale: an update after 40 years.

Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet 1974,2:81-84. PMID 4136544.

The Glasgow Structured Approach to Assessment of the Glasgow Coma Scale. (n.d.). Retrieved February 13, 2018, from www.glasgowcomascale.org.