Glasgow Coma Score

The GCS evaluates three independent neurologic responses: eye opening, motor response, and verbal response All parameters may be significantly affected by systemic factors such as severe hypotension or significant drug/alcohol intoxication or by local factors, including ocular trauma, intubation, extremity fractures, and spinal cord injury. Iatrogenic paralysis/sedation affects the score and may render the GCS inapplicable.

The eye opening and verbal responses are simple to record. The motor response has traditionally been recorded as the best reaction in response to deep pressure or pain. Thus a patient who is hemiplegic may still receive a motor score of 6. In their original paper, Teasdale and Jennett specifically proscribed the manner in which the evaluation of all three parameters was to be undertaken. Noxious stimuli to the nailbed were to be applied to elicit decorticate or decerebrate responses, while painful stimuli to the head neck or trunk were used to test for localization. Eye opening in response to pain was to be tested distant to the face to prevent a grimacing reflex from keeping the eye shut.

It is generally accepted that a GCS of 13 to 15 is associated with minor TBI, a GCS of 9 to 12 reflects moderately severe TBI, and a GCS of 3 to 8 indicates severe TBI. It is common practice to attach a modifier (“t”) after the score if a verbal response cannot be recorded due to intubation.

The GCS cannot be used in preverbal children, and a children’s coma scale has been developed. The eye and motor responses mirror those of the GCS. For the verbal response, a score of 5 is given if the child smiles, orients to sounds, follows objects, and interacts. Scores of 4 to 1 include both a component related to crying and one to interaction. Thus a score of 4 indicates that the child cries consolably and interacts inappropriately; 3, that crying is inconsistently consolable and there is moaning; 2, that the child cries inconsolably and is restless; and 1, that there is an absence of crying or interaction.

Several studies have shown an association between both a prehospital and in-hospital GCS and outcome. As an example, patients having a GCS of 6 to 15 in the field were 30 times more likely to have a good outcome than with a GCS less than 6. A prospective study of emergency medical service (EMS) and in-hospital GCS determination found a positive predictive value of 77% for a poor outcome (dead, vegetative, or severely disabled) in patients with a GCS of 3 to 5 and 26% with a GCS of 6 to 8.

From a clinical perspective, the GCS is routinely recorded at regular intervals during the neurocritical care phase of TBI management. Various clinical decisions have come to be based on GCS thresholds, such as the need for intubation and consideration of ICP monitoring when the GCS is less than 8. Similarly, during ongoing evaluation, a decline of two or more points is generally considered clinically significant.

Efforts in developing the GCS have been extended to outcome assessment. The Glasgow Outcome Scale (GOS) was introduced in 1975 and is the cornerstone in outcome assessment, with high intrarater reliability. There are five potential outcomes, that is, death, persistent vegetative state, severe disability, moderate disability, and a good outcome.

A good recovery is defined as a resumption of a normal life despite minor ongoing disability. With moderate disability, a patient is disabled but independent, able to perform all activities of daily living, and work in a sheltered setting. Severely disabled patients are conscious but totally dependent on others for care. In the per-sistent vegetative state, the patient is unresponsive and speechless but may open the eyes and appear to be able to track.

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