Additions to Glasgow Coma Scale Aid Prognosis in TBI

Laurie Barclay, MD


May 15, 2018

Simplifying the Use of Prognostic Information in Traumatic Brain Injury. Part 1: The GCS-Pupils Score: An Extended Index of Clinical Severity.

Murray GD, Brennan PM, Teasdale GM
J Neurosurg. 2018 April 10. [Epub ahead of print]

Simplifying the Use of Prognostic Information in Traumatic Brain Injury. Part 2: Graphical Presentation of Probabilities.

Murray GD, Brennan PM, Teasdale GM
J Neurosurg. 2018 April 10. [Epub ahead of print]


In 1974, Bryan Jennett and Graham Teasdale first developed the Glasgow Coma Scale (GCS) to evaluate coma and level of consciousness based on eye, motor, and verbal responses, with total scores ranging from 3 (deep coma) to 15 (full consciousness). Since it was first introduced, the GCS has been widely used by medical personnel, particularly for assessment of traumatic brain injury (TBI). Subsequent scoring systems have been too complex for widespread clinical implementation. Teasdale and colleagues have now developed a modified GCS to facilitate rapid TBI assessment in the emergency setting.

Because pupil reactivity and GCS score are the two clinical characteristics of greatest prognostic value in patients with TBI, particularly those with more severe TBI, the investigators calculated a GCS-Pupils score (GCS-P; scored from 1 to 15) by subtracting the number of nonreactive pupils (0, 1, or 2) from the GCS score (3-15). They evaluated GCS-P using pooled data from CRASH[1] (Corticosteroid Randomisation After Significant Head Injury; N = 9045) and IMPACT[2] (International Mission for Prognosis and Clinical Trials in TBI; N = 6855), the two largest TBI databases.

Although the GCS score and pupil response were each separately related to outcome, combining both increased the information yield, with the prognostic value of GCS-P comparable to that of more complex assessments. The association between decreases in GCS-P and worse outcomes occurred across the complete range of possible scores.

Creation of two lower scores (GCS-P 1 and 2) than the GCS (scored from 3 to 15) provided additional information about injury severity and outcomes. At a GCS score of 3, the mortality rate was 51% and the rate of unfavorable outcome was 70%, whereas at a GCS-P score of 1, these declined to 74% and 90%, respectively. Another advantage of GCS-P over GCS was the absence of the paradoxical finding that a GCS score of 4 was associated with a worse outcome than a GCS score of 3.

In the second part of this paper, the investigators determined the incremental value of adding patient age and CT findings to GCS-P, using CRASH and IMPACT data to develop graphic representations showing risks for death and likelihood of good outcomes after TBI. Mortality increased with increasing patient age and with decreasing GCS-P at all ages. Conversely, good outcomes were more likely with younger age and higher GCS-P. These findings were incorporated into two prediction charts based on the GCS-P and patient age stratified into 5-year increments between 15 and 85 years, showing mortality risks and favorable outcomes at 6 months after TBI.

The investigators then calculated scores (0-3) based on the number of different types of brain CT abnormalities (hematoma, absent cisterns, or subarachnoid hemorrhage) and created two sets of three predictive charts based on the GCS-P, patient age, and number of CT abnormalities (GCS-PA CT charts). One set of charts shows mortality risk 6 months after TBI, and the other shows likelihood of a favorable outcome at the same time point 6 months after TBI, to facilitate decision making by clinicians and communication among clinicians, patients, and caregivers.

Differences in outcome are very similar between patients with or without a hematoma, absent cisterns, or subarachnoid hemorrhage; but in combination, there was a gradation in risk for increasing numbers of any of these abnormalities. These data gave added value over age and GCS-P alone.


The original GCS has long been the standard for initial assessment and prognostication in TBI. Adding the number of reactive pupils improved prognostic value without complicating the assessment. Combining the GCS-P with patient age was substantially more informative than the GCS-P, age, GCS score, or pupil reactivity alone; and combining these with the number of CT abnormalities was of additional benefit.

These new, GCS-based assessment tools for patients with TBI offer more information on injury severity and prognosis than the original GCS but are still rapidly administered and easy to use. The findings are objective and the scores standardized, lowering the risk for influences from biases and facilitating communication among medical personnel, family, and patients. In addition to evaluating individual patients, these scores and charts may help identify patient subgroups for inclusion in research protocols.

However, these modified GCS scores should not be used alone for management of specific patients, nor should they replace clinical judgment, but instead they should be considered in light of individual patient characteristics potentially affecting outcome.


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