BONUS: Take the OT Dude GCS Quiz at the end to test your knowledge.
Here are some ways I remembered how to to calculate the Glasgow Coma Scale (GCS) when I was an EMT (and used it daily). This is important to know well because (1) it may show up on your NBCOT Exam (2) it is easy to get right and is a “freebie” because it is a simple calculation if you understand it (2) you may see it in clinical practice as an occupational therapy practitioner.
You may learn GCS in OT school, but due to how much content is covered in the OT curriculum, you may not have had time to learn how to actually calculate GCS. When calculating GCS, it is best to write it out and sum up visually instead of mentally in your head. If you do not calculate GCS frequently, it is very easy to make a mistake.
When taking the NBCOT exam, you will get a “scratch” paper to allow you to calculate GCS visually. Again, don’t try to do this mentally because (1) you can get it wrong (2) why waste more brain cells during the NBCOT exam when you have many more questions to answer still.
GCS adds up to 15. To remember the sub-sections, memorize 4, 5, 6.
4+5+6 = 15.
Unfortunately, the lowest score for poor performance is 1, not 0. So the lowest score a patient can get on the GCS is not the sum of 0, but 3.
So memorize (3),4,5,6. 3 for the lowest score. 4+5+6 gives you 15, the highest possible score for “normal” mentation and response.
Let’s pull up a GCS chart:
I like this chart because it shows the color of severity, pictures for eyes, verbal, and motor response, and shows the severity ranges. But it is kind of confusing terminology, as you will see later for motor response.
- G: gaze (eyes)
- C: conversation (verbal)
- S: sensation (motor response)
GCS: in the order of G (4) -> C (5) -> S (6) = 15
Knowing that 1 is the lowest score, you already know 3 of them for each category of eyes, verbal, and motor response.
For eye-opening, someone who is ‘normal’ would have them open (4). Then to sound, like you calling someone’s name (3). Then when that fails, you produce a noxious stimuli “to pressure” (2). We went over (1) as none. Easy so far.
If you think of Verbal response as the A&O (alert and oriented questions), this subsection is really easy and makes sense.
Someone who is alert and oriented x 3 (or 4, depending on whether you ask the situation question) would score a (5), remember 4-5-6. If they get the A&O questions wrong, they are “confused” so that’s a (4). Think about how a baby learns to talk. They make no sounds (1) for none (I know that newborns are born and can cry technically). Then they make sounds (2), e.g., “ba ba ba”, like my son right now who is 7 months old. Then they learn words (3). And then they say silly things “confused” (4). Then they can answer you correctly (5). So go backwards starting from (1) for verbal response all the way up to (5).
Last we have motor response. It helps to know what decorticate and decerebrate look like:
Again, (1) for none. (2) for decerebrate and (3) for decorticate posturing. When it comes to the NBCOT exam, pay attention to how the upper extremities are positioned. This is likely how they will describe the patient to you if they were doing this poorly in motor response. This is just something I memorized visually for the terms decerebrate and decorticate.
(4) for motor is the person just withdraws generally from pain, like if they were barely conscious. That leaves us with (5), moves to localized pain, or specifically the body part that you present a noxious stimuli, e.g, pinching their fingers; it is also purposeful compared to (4). Pay attention to the phrasing on the question because this can mean the difference between (4) and (5), which means you can still get the question wrong because you are “1 point’ off when adding the subsection for a motor response even though you got the eye and verbal response correct.
Tip: remember that localized (5) is doing “better” than withdrawal from pain (4). “It is better to buy local and support the local business”.
Memorize that moderate severity range from 9-12. Then you know that anything below 9 is severe and anything above 12 is mild to normal.
Overall, the GCS is really not too bad. Just break it down into 3 separate parts, calculate each score for the subsection, then add them together to get the final score.
To help OT students out, I made a GCS Quiz to test your knowledge. Based on the question, try to calculate the total GCS score. No cheating – do not look at the chart.
Note: Physiologically in the real world, some patient’s probably won’t present with some of these combinations, as there is usually a pattern depending on the severity, but it is good practice anyway to familiarize yourself with the math and the phrases used. The quiz just randomly generates each G/C/S to come up with a combination and I am not smart enough to make it more sophisticated. 😛
Hope this helps!