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WHAT IS THE GLASGOW COMA SCALE?

The Glasgow Coma Scale (GSC) provides an objective means of recording the conscious state of a person following a traumatic brain injury. Scores between 3 (deep unconsciousness) and 14 or 15.

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 voice
  • 2 = to pain
  • 1 = none

Verbal Response (V)

  • 5 = normal conversation
  • 4 = disoriented conversation
  • 3 = words, but not coherent
  • 2 = no words, only sounds
  • 1 = none

Motor Response (M)

  • 6 = normal
  • 5 = localized to pain
  • 4 = withdraws to pain
  • 3 = decorticate posture (an abnormal posture that can include rigidity, clenched fists, legs held straight out, and arms bent inward toward the body with the wrists and fingers bend and held on the chest)
  • 2 = decerebrate (an abnormal posture that can include rigidity, arms and legs held straight out, toes pointed downward, head and neck arched backwards)
  • 1 = none

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

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

  • Severe: GCS 3-8 (You cannot score lower than a 3.)
  • Moderate: GCS 9-12
  • Mild: GCS 13-15

Mild brain injuries can result in temporary or permanent neurological symptoms and a neuro-imaging 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 younger 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 pain
  • 1 = none

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

Motor Response (M)

  • 6 = moves spontaneously or purposefully
  • 5 = withdraws from touch
  • 4 = withdraws to pain
  • 3 = decorticate posture (an abnormal posture that can include rigidity, clenched fists, legs held straight out, and arms bent inward toward the body with the wrists and fingers bend and held on the chest)
  • 2 = decerebrate (an abnormal posture that can include rigidity, arms and legs held straight out, toes pointed downward, head and neck arched backwards)
  • 1 = none

Pediatric brain injuries are classified by severity using the same scoring levels as adults, i.e. 3-8 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, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet 1974,2:81-84. PMID 4136544.

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