Glasgow Coma Scale (GCS)

GCS short for Glasgow Coma Scale (GCS), is an objective score based description to conduct a proper health assessment for the impaired consciousness patients.

• Eye opening - the E
• Verbal responses - the V
• Motor control - the M

Reporting each of these separately provides a clear, communicable state of the patient, the accumulative results in each component of the scale defines the Glasgow Coma Score

The Glasgow Coma Scale (GCS) has been widely adopted by health professionals and clinical protocols, procedures and guidelines to manage patients of trauma or critical illness and communicate their conditions.

Background and History

1960 - Machine Industry

Assessment and treatment of head injuries became more popular due to the rise of head injuries as a result of the engines machine industry.

Health professionals noticed after head trauma, general patients had poor recovery, as a result health professionals blamed the poor assessment procedure at that time.

Since then, different assessments for coma scales (result of head injuries) were introduced.

1970 - Introduction

Bryan Jennett and Graham Teasdale started the formal and structured work to introduce the Glasgow Coma Scale (GCS) that we know today.

Simplicity was the key to get the scale adopted and developed.

1974 - Publication

1. Eye assessment
2. Verbal assessment
3. Motor assessment

These components were scored based on clearly defined behavioural responses. Clear instructions for administering the scale and interpreting results were also included. The original scale is identical to the current scale except for the motor assessment. The original motor assessment included only five levels, combining "flexion" and "abnormal flexion". This was done because Jennett and Teasdale found that many people struggled in distinguishing these two states.

1975 - Adoption

The Glasgow Coma Scale (GCS) was initially adopted by nursing staff in the Glasgow neurosurgical unit Especially following a 1975 nursing publication, it was adopted by other medical centres.

1976 - Refinement

Glasgow Coma Scale (GCS) was updated by Teasdale to include the six scale of motor assessment, the flexion movements.

Due to the reliability of diagnosing the flexion movements, normal and abnormal flexion could have a clear impact on the clinical outcomes.

GCS accumulative (total) score was introduced to improve the clinical outcome of disability and mortality.

1978 - Widespread

GCS was adopted in the clinical use after the following:

The neurological trauma expert of that time, Tom Langfitt endorsed and supported the GCS score to be adopted in neurosurgical fields.

The Advanced Trauma Life Support (ATLAS) captured GCS in the early version for the learning pathways of the health professionals.

Scoring structure (EVM)

1. E   -  Eye movement
2. V  -  Verbal control
3. M -  Motor control

The levels of response in the components of the Glasgow Coma Scale (GCS) are ‘scored’ from 1, for no response, up to normal values of 4 (Eye-opening response) 5 (Verbal response) and 6 (Motor response)

The total Coma Score thus has values between 3 and 15, three being completely unresponsive and 15 being responsive. 

The score is the sum of the scores as well as the individual elements. For example, a score of 10 might be expressed as GCS10 = E3V4M3.

1. No eye opening
2. Eye opening to pain
3. Eye opening to sound
4. Eyes open spontaneously

1. No verbal response
2. Incomprehensible sounds
3. Inappropriate words
4. Confused
5. Orientated

1. No motor response
2. Abnormal extension to pain
3. Abnormal flexion to pain
4. Withdrawal from pain
5. Localising pain
6. Obeys commands

Adelaide Coma Scale (Paediatric Coma Scale)

The Glasgow Coma Scale (GCS) can be applied to children with the following age consideration and restriction, however a new version of the Glasgow Coma Scale (GCS) adapted for use in children called the Adelaide Coma Scale (Paediatric Coma Scale).

Like the Glasgow Coma Scale (GCS), Adelaide Coma Scale (Paediatric Coma Scale) assesses eye opening, verbal response, and motor response, on a score out of 15.

Adelaide Coma Scale (Paediatric Coma Scale) takes into consideration the child’s age and neurological development when evaluating responses.

Infants are not able to provide the necessary verbal responses for the practitioner to use the scale to assess their orientation or obey the commands to evaluate their motor response.

Risks and Challenges

The following risks may impact the Glasgow Coma Scale (GCS) assessment. 

1. Pre-existing factors
   • Language barriers
   • Intellectual damage
   • Neurological deficit
   • Hearing loss
   • Speech impediment
2. Effects of current treatment

   • Physical (e.g., intubation): If a patient is intubated and unable to speak, they are evaluated only on the motor and eye-opening response and the suffix T is added to their score to indicate intubation.
   • Pharmacological (e.g., sedation) or paralysis: If possible, the clinician should obtain the score before sedating the patient.
3. Effects of other injuries or lesions
   • Orbital/cranial fracture
   • Spinal cord damage
   • Hypoxic-ischemic encephalopathy after cold exposure

    

There are instances when the Glasgow Coma Scale (GCS) is unobtainable despite efforts to overcome the issues listed above. It is essential that the total score is not reported without testing and including all of the components because the score will be low and could cause confusion.

Clinical Realisation and Perception

Response assessment using the Glasgow Coma Scale (GCS) is widely used to guide the early management of patients with head injury or other type of acute brain injury.

Decisions in severely debilitated patients include emergency management such as securing the airway and triage to determine patient transfer.

Decisions for less severely disabled patients include the need for neuroimaging, admission for observation, or discharge. Glasgow Serial Coma Scale (GCS) assessments are also important in monitoring a patient's clinical course and guiding changes in management.

The information gained from the three components of the scale varies across the response spectrum. Changes in motor response are the predominant factor in severely impaired patients, while ophthalmic and verbal are more beneficial to lesser degrees. In individual patients, clinical findings in three components should be reported separately. The overall score indicates a concise overall index that is useful but with some information missing.

In both preverbal and verbal paediatric patients, the Glasgow Coma Scale (GCS) is an accurate marker for clinically significant traumatic brain injury (eg, injury requiring neurosurgical intervention, intubation for more than 24 hours, hospitalization for more than two nights, or causing death).

The Glasgow Coma Scale (GCS) has been included in several guidelines and ratings.

1. Advanced Trauma Life Support (ATLS);
2. The Brain Trauma Foundation;
3. The Critical Care Score Systems (APACHE II, SOFA); and
4. The Advanced Cardiac Life Support Systems.

The Recommendation 

It is recommended that the health professionals have sufficient knowledge of the Glasgow Coma Scale (GCS) to be able to record correctly and reliably the score within the medical record system, hospital information system or any other health record.