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GCS-40: The Glasgow Coma Scale turns 40 and gets a facelift

A team from the Institute of Neurological Sciences updated the GCS and developed a Structured Approach to Assessment to minimize variation in stimulation and response measurement


An updated version of the Glasgow Coma Scale aims to minimize the variation in application of the original version of the Scale. The changes to the Scale, now referred to as GCS-40, fall into three categories.


A few years ago, the Glasgow Coma Scale (GCS) quietly celebrated its 40th birthday. Originally developed in 1974 by Professors Graham Teasdale and Bryan J. Jennett of the University of Glasgow (Scotland), the GCS has been adopted by over 60 countries and translated into 40 languages to help clinicians assess and document the level of consciousness in patients with head trauma.

Researchers took the opportunity of the 40th anniversary, to do an assessment of the Scale itself and found that an unintended consequence of wide adoption was that there was also wide variation in how the Scale was applied.

Clinicians were using different methods to apply stimuli to the patient as well as different standards in interpreting the responses. This caused concern as it could lead to different clinicians assigning different scores for the same patient. It was also troubling to researchers looking to use the Glasgow Coma Scale in studies that reviewed treatment and outcomes in brain-injured patients.

Led by Sir Graham, a team from the Institute of Neurological Sciences updated the GCS and developed a Structured Approach to Assessment to minimize the variation in application of the original version of the Scale. The changes to the Scale, now referred to as GCS-40, fall into three categories.

1. GCS-40 methods to apply stimulation

GCS-40 now instructs clinicians to apply pressure in three specific locations, as needed, to note the increasing intensity required to elicit response.

Begin with pressure to the fingertips, then move to the trapezius muscle and finally the supraorbital notch if needed. Rubbing the sternum is not recommended as it can cause soft-tissue damage and the responses to it are not predictable or reliable.

2. The patient’s response to stimulation

In the Eye category, “speech” was changed to “sound” to clarify that a specific command, such as “open your eyes” is not needed to qualify for this level of responsiveness. The patient would qualify for sound response if they opened their eyes to the sound of you setting your cardiac monitor on the floor. The term “pain” was replaced with “pressure” to highlight that causing the patient excessive pain is not needed. Stimulation in the form of pressure as noted above is sufficient.

The Verbal response category was updated to move from the subjective term “inappropriate speech” to simply “words.” If the patient response lacks structured sentences or phrases, they are given credit for “words.” Additionally, instead of “incomprehensible speech,” the GCS-40 assesses for “sounds.” This would be applied when a patient is making a verbal effort but no recognizable “words” are noted. It should be noted that the “words” that the patient utters do not need to be oriented or appropriate, just recognizable as words.

Choices within the Motor category remain unchanged from what has been common practice for the last several years, although it is interesting to note that the authors did not differentiate normal and abnormal flexion response in the original Scale. Those differences are now formally recognized and defined in GCS-40.

3. Documentation of conditions that prevent assessment of the full GCS-40

An important change to the Glasgow Coma Scale is that it now includes a method to document when the patient has a condition that prevents the provider from performing a complete assessment. In the past, if the patient was intubated, the GCS was basically skipped or documented as not reliable because it could not be completed. Even if the patient could open their eyes and follow commands, there was no standardized way to note that the verbal response was zero because they were intubated.

In the GCS-40, each category can be answered as “NT-not tested” if a condition prevents assessment. For example, a patient whose eyes are swollen shut but responds with oriented speech and follows commands can be documented as E-NT, V-5, M-6.

What about kids?

The GCS-40 can be applied as written to children over 5 years of age but modifications will need to be made for younger children and infants that cannot be expected to provide an oriented response, words or follow commands. The authors of the GCS-40 do not provide specific recommendations but note that existing pediatric modifiers to the GCS will likely apply.

Pupillary response

Wait, there’s more…

Sir Graham and his team also added a new element to the GCS-40 to take pupillary response into account. If one pupil is non-reactive to light, one point is subtracted from the total GCS-40 score. If both pupils fail to constrict, two points are subtracted. The modification, referred to as GCS-P, is not meant to replace additional assessment and documentation of pupillary response but researchers have noted that decreased response is associated with a worsening of outcome across the range of GCS Scores.“ Documentation of pupillary response may be helpful in longer-term research of traumatic brain injuries, their treatment and outcomes.

When does this take effect?

You probably have not seen the GCS-40 in your electronic charting software yet. The National EMS Information System (NEMSIS) has not added GCS-40 to their data set, so patient care report vendors are not likely to build those fields right away. It was, however, recently added to the National Trauma Data Bank and trauma centers are beginning to collect the GCS-40 and submit the information to state and national trauma registries. As use among trauma centers increases, the updated Scale will eventually be added to EMS assessments and patient care documentation. The GCS-P is not currently referenced in either the NTDB or NEMSIS.

Learn more about GCS-40

The Institute of Neurological Sciences has a complete collection of educational tools including videos, FAQs, GCS-40 assessment charts and a self-test. Their site details the history of the GCS and those that developed and updated the Scale. A more formal publication of the GCS-40 revision was published in Nursing Times.


Table/courtesy Nursing Times

Michael Fraley has over 30 years of experience in EMS in a wide range of roles, including flight paramedic, EMS coordinator, service director and educator. Fraley began his career in EMS while earning a bachelor’s degree at Texas A&M University. He also earned a BA in business administration from Lakeland College. When not working as a paramedic or the coordinator of a regional trauma advisory council, Michael serves as a public safety diver and SCUBA instructor in northern Wisconsin.