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Glasgow Coma Scale

Medically reviewed by Last updated on May 1, 2023.

  • The Glasgow Coma Scale (GCS) is a tool that healthcare providers use to measure a person's level of consciousness. It is most often used when a person has a traumatic brain injury (TBI). A car accident, fall, or being hit on the head with a hard object can cause a TBI. A TBI can injure the person's brain badly enough that he or she is no longer conscious (awake and aware). Healthcare providers use the GCS after making sure the person's airway, breathing, and circulation (blood flow) are not in danger.
  • A brain injury can damage the parts of the brain that help the person sleep and wake normally. When this happens, the injured person stays unconscious and cannot be woken. Healthcare providers call this a coma. The most common cause is a TBI. Other causes include medical conditions such as stroke, seizures, or diabetes. A person may be in a coma for days, weeks, months, or even years.


What the Glasgow Coma Scale tests:

The GCS measures different types of responses. A higher score means a higher level of consciousness. A lower score means a lower level of consciousness.

  • Eye opening: This response is scored on a scale of 1 to 4 points. More points are given if the person opens his or her eyes on his or her own, or after being touched. A person is found to be in 1 of 4 levels of consciousness, based on when and why he or she opens his or her eyes.
  • Verbal response: This response is scored on a scale of 1 to 5 points. Healthcare providers ask basic questions and give points for correct answers. Some people are unable to answer questions correctly, or they say the wrong words. Others are not able to say words at all. They can only make sounds.
  • Motor response: This response is scored on a scale of 1 to 6 points. Healthcare providers ask the person to move parts of his or her body such as an arm or leg. A person with a TBI may not be able to move his or her body, even if he or she has no other injuries. The person gets more points for moving the way healthcare providers ask.

Test used to check the level of consciousness in children:

Children under the age of 2 years may be given a different type of GCS. This test is called the Children's Coma Scale (CCS). You may also hear healthcare providers call it the Pediatric Glasgow Coma Scale, or P-GCS. The CCS is used because very young children cannot speak or move as well as adults. Healthcare providers give points for how well the child opens his or her eyes by himself or herself. They also give points for cooing, babbling, and crying sounds instead of words. Healthcare providers may do the CCS with a child many times while he or she is in the hospital. By looking at the CCS results over time, healthcare providers can see signs that the child is getting better.

When and how the Glasgow Coma Scale is used:

  • Healthcare providers give the Field Glasgow Coma Scale (f-GCS) to an injured person before taking him or her to the hospital. The f-GCS gives a starting number. Healthcare providers use this number to help them get ready for when the person arrives at the hospital. A person who has a low f-GCS score may need help with breathing, or he or she may need to have surgery right away. Healthcare providers can compare the person's f-GCS score with later Glasgow Coma Scale scores. This helps them know how well the person is improving.
  • The GCS scores can help healthcare providers estimate how a person will recover after a brain injury. If the scores get higher over time, there is a good chance that the person will keep improving. After a brain injury, a person may recover and have no lasting effects. Other people may have long-lasting effects, and need help with activities such as brushing their teeth or getting dressed. Some people stay in a long-term vegetative state. A persistive vegetative state occurs when a person is alive, but not responsive to anything.

Disadvantages of the Glasgow Coma Scale:

The GCS does not work as well if healthcare providers cannot score all 3 parts of the test.

  • Healthcare providers cannot score the person's verbal responses if:
    • The person drank alcohol before his or her injury. Alcohol may make his or her speech hard to understand.
    • The person has an endotracheal (ET) tube in his or her throat to help him or her breathe. The ET tube makes talking difficult.
    • The person was given medicine to decrease pain or swelling. The medicine may make him or her too sleepy to talk.
  • Healthcare providers cannot score how well the person opens his or her eyes if his or her eyes are swollen shut from the injury.
  • Healthcare providers cannot score the person's body movements if an injury causes pain with movement, or makes the person unable to move.
  • The GCS does not check if the person can learn and remember new things. A person's ability to form new memories is important in helping healthcare providers predict his or her recovery after a TBI.

The Trauma Score and Injury Severity Score:

The Trauma Score and Injury Severity Score (TRISS) is another test that healthcare providers use when a person has been injured. Healthcare providers check the person's age, blood pressure, and how the pupils in his or her eyes respond to light. A person's pupils normally get smaller in light and larger in darkness. If pupils get smaller and larger correctly, it may mean the person's brain injury is not as severe. The TRISS helps healthcare providers plan the person's care.

For support and more information:

  • Brain Injury Association
    1608 Spring Hill Road
    Vienna , VA 22182
    Phone: 1- 703 - 761-0750
    Phone: 1- 800 - 444-6443
    Web Address:
  • National Institute of Neurological Disorders and Stroke
    P.O. Box 5801
    Bethesda , MD 20824
    Phone: 1- 301 - 496-5751
    Phone: 1- 800 - 352-9424
    Web Address:

Follow up with your doctor as directed:

Write down your questions so you remember to ask them during your visits.

Contact the person's healthcare provider if:

  • The person suddenly gets dizzy.
  • The person suddenly has trouble remembering things.
  • You have questions or concerns about the person's condition or care.

Seek care immediately if:

  • The person begins to vomit.
  • The person states that his or her vision is blurry, or he or she is seeing double.
  • The person has a wound and it starts bleeding, or the stitches come out.
  • The person is hard to wake up.
  • The person's speech is hard to understand.
  • The person's arms or legs get weak, or the person says he or she cannot feel them.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Further information

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