The Glasgow Coma Scale (GCS) is a tool medical professionals use to objectively evaluate the degree to which a person is conscious or comatose. Also referred to as the "Glasgow Coma Score," it operates on a scale of "3" to "15," in which progressively higher scores indicate higher levels of consciousness.

For example, while a patient who is profoundly unconscious would receive a 3 according to the Glasgow Coma Scale, conscious, healthy adults would be rated at 15.

Immediately after a head trauma, emergency doctors and nurses will use the Glasgow Coma Scale to assess a patient’s condition. Others who use the GCS include intensive care staff, EMTs and chronic care professionals.

Brief History of the GCS

Graham Teasdale and Bryan J. Jennett first developed the Glasgow Coma Scale in 1974. At the University of Glasgow, these neurosurgery professors continued to develop important work in the field of head traumas, publishing Management of Head Injuries in 1981.

Through their work, Teasdale and Jennett have helped medical staff around the world successfully diagnose and care for coma patients. Additionally, they have inspired others to develop similar evaluation methods, in particular the "Rancho Los Amigos Scale." The RLAS is a diagnostic tool used to evaluate traumatic brain injury (TBI) patients.

How the Glasgow Coma Scale Works

Given that the GCS is based on a 15-point scale, patients’ "scores" are determined by assigning points to their various physical responses. Visual ability, verbal responsiveness and motor skills are all examined and evaluated in the GCS.

Consult the table below for a breakdown of how the Glasgow Coma Scale's points are assigned.

 

Physical Response
l/
Points Assigned
->
1 2 3 4 5 6
Visual Response Eyes remained closed. Pain causes eyes to open. Voices cause eyes to open. Eyes open randomly. N/A N/A
Verbal Ability Silence. Minimal, indistinguishable sounds. Mumbles obscenities. Incoherent rambling. Normal conversation. N/A
Motor Skills Immobile. Pain causes extension movements. Pain causes flexion movements. Pain causes movement away from stimuli. Complicated movement in response to pain. Moves on command.

Because small children can suffer from loss of consciousness just as adults can, the Glasgow Coma Scale also includes an addendum to the verbal ability portion of the scale. This adjustment categorizes verbal responses according to the following point-scale:

  • 1 point: Silence, unresponsive
  • 2 points: Grunts
  • 3 points: Incessant crying (For babies, crying will occur independent of unpleasant stimuli.)
  • 4 points: Mumbles illogical words (Babies will cry appropriately and respond positively to consolation.)
  • 5 points: Speaks appropriately (Babies will smile and chatter appropriately.)

Keep in mind that, although the descriptions of what a "point" entails may be straightforward, it's not always easy for medical professionals to assess in which category patients fall. For example, swollen eyes due to head trauma may prevent doctors from evaluating visual responsiveness.

Consequently, both doctors and nurses regularly use the Glasgow Coma Scale multiple times on individual patients to determine their evolving needs and changing conditions including recovery.