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Glasgow coma scale

The Glasgow Scale is a widely extended global neurological assessment tool. It is used in general lines to assess the level of consciousness of a patient with some type of brain damage . Thanks to this tool, medical personnel can quantify three key parameters to determine the diagnosis: the ocular response, the verbal response and the motor response.

In its beginnings, the Glasgow Scale was used to determine the severity of those patients who had suffered a head injury. Today his field is vastly broader; This tool is used routinely to assess altered states of consciousness, such as the depth of coma.

What is the Glasgow Scale?

The Glasgow Scale is a tool used in the medical field to quantify the level of consciousness of a certain individual . It is therefore the tool used to establish the prognosis of an injury that has caused some type of brain damage.


The origin of the Glasgow Scale (or consciousness) dates back to the 1970s. It was designed by two neurosurgeon doctors at Glasgow Hospital in England. From then on, this tool began to be used in different hospitals in the United Kingdom and, given its efficiency and effectiveness, its use spread throughout the world.

When a person suffers a trauma to the head, a neurological examination performed as quickly as possible is essential for their recovery. One of the most important aspects is the level of consciousness, for which the Scale of Consciousness is fundamental. In this way, based on the score obtained by the patient, the doctor can know the severity of the injury in question.

This tool is also used to determine deep coma states and evaluate their evolution.

How does the Glasgow Scale work?

This tool allows the measurement of the level of consciousness, as well as the cognitive state, of a certain person. To do this, it evaluates three fundamental aspects: motor response, verbal response and eye opening .

The values ​​provided oscillate between 3 and 15 points ; 3 points correspond to the minimum possible, compatible with a deep coma, while 15 points are given when the patient does not present any type of cerebral affectation.

Interpretation of the glasgow coma scale

Eye aperture

In order to open the eyes, it is an indispensable condition that the patient is awake; In addition, this tool takes into account whether or not it is attentive to the environment. It is an action that requires that the neurons of the brainstem, thalamus and hypothalamus , in addition to the reticular system, do not have any type of damage.

Depending on the degree of stimulation necessary to obtain a response from the patient , the doctor gives a higher or lower score to this category.

To avoid an error in the measurement of this parameter, it is essential to rule out injuries that may affect ocular opening in any way, such as trauma to the eyelids or facial paralysis.

If the eye opening is done spontaneously , the score is four points. Meanwhile, if the eye opening occurs when speaking, the score awarded is three points.

Meanwhile, if the patient opens his eyes only in response to pain, the score corresponding to this parameter is two points. And finally, if there is no eye opening to any stimulus, one point.

Motor response

This category of the Glasgow scale assesses brain function at the global level. First, the doctor orders a series of simple tasks to assess the patient’s response .

In the event that this does not obey the assigned tasks, the doctor proceeds to apply different painful stimuli to determine whether or not there is any type of movement.

The motor response score is given as follows. If the patient obeys all the commands related to the movement of various areas of his body, he scores a total of six points.

In case you localize the pain, the score is five points. If there is a withdrawal of pain, you are awarded four points. If abnormal flexion occurs, three points; and if an abnormal extension occurs, a colon. Finally, if the patient does not give any kind of response, he is awarded only one point.

Verbal response

Regarding the verbal response, it includes two processes that are very important; the ability to understand a given instruction and to respond to it .

Thus, the main objective of this category of the Glasgow scale is to assess the level of consciousness and alertness of the patient, with himself and with the environment.

In addition, the evaluation of the verbal response allows to determine if there is any type of injury in the language centers.

If the patient is fully oriented, the score is five points. Meanwhile, if you are confused, your score is four points. If the words are inappropriate, three points. In case you make incomprehensible sounds, colon. And, if there is no answer, one point.

Glasgow Scale Indices

The Glasgow Scale is divided into a total of three categories, as we have indicated in the previous section. The maximum and normal score is 15, while the minimum is 3.

In general terms, a mild head injury is considered to be one with a score of between 13 and 15 points. Meanwhile, it is moderate when the score ranges between 9 and 12 points. A score on the Consciousness scale less than 8 implies a situation of a serious nature, in some cases critical.

Glasgow Impact Scale

There is also a series of evolutionary scale of the coma; the most widely used in the health field is the Glasgow impact scale. This divides the patient’s state into four states, plus death; each of the degrees is characterized by a different social and labor integration.

  1. Death
  2. Vegetative state: the patient is completely unable to interact in any way with the environment around him.
  3. Severe disability: the patient can obey orders, but is not able to live independently.
  4. Moderate disability: the patient can live independently, but is unable to resume his professional life.
  5. Good recovery


A prolonged state of unconsciousness is known as coma, in which the patient does not respond to any type of stimulus from the environment, not even pain.

Types of coma

There are different types of coma, each with its own characteristics and prognosis.

  • Toxic-metabolic encephalopathy : it is known as an acute condition in which the patient presents symptoms of confusion and / or delirium. The most common causes of this type of coma are systemic diseases, infections, and failure of certain organs.
  • Anoxic brain injuries: it is a brain condition caused by the total lack of oxygen to this organ, which can cause cell death of tissues. In the vast majority of cases, it responds to cardiac arrest.
  • Vegetative state: it is a serious state of unconsciousness. The person is nowhere near aware of his surroundings and is completely incapable of making any voluntary movement.
  • Captivity syndrome: it is a neurological condition that occurs very infrequently. The patient is only able to move his eyes, but remains awake and alert.
  • Brain death: an irreversible situation in which all brain functions die. The prognosis is extremely complicated.
  • Induced: the induced coma is used to protect the brain inflammation after suffering a given lesion. Thus, the patient receives a controlled dose of an anesthetic to cause lack of consciousness.

Causes of glasgow coma

In relation to the causes that give rise to a comatose state ( coma scale ), it is estimated that in more than 50% of cases patients have suffered some type of head trauma or a disorder related to the circulatory system in the brain. Here are the causes that most often lead to a coma.


  • A head injury can cause the brain to swell. As a result of the swelling, pressure is generated against the skull, which can damage the RAS, the reticular activation system; It is the area of ​​the brain responsible for awareness and arousal.


  • Bleeding in certain areas of the brain can cause a glasgow coma , due to swelling of the organ, thus leading to damage to the brainstem and RAS. Some of the most common causes of bleeding in the brain are high blood pressure, brain aneurysms, and tumors.

Blood sugar levels

  • In people with diabetes, a coma can occur when blood sugar levels remain very high for a long period of time; it is what is known as hyperglycemia. In some cases, hypoglycemia , very low blood sugar levels, can also lead to a coma. In both situations the situation is reversible once the blood sugar levels are corrected.

Oxygen deprivation

  • Oxygen is essential for the brain to function properly. When cardiac arrest occurs, there is a sudden cut in blood flow and oxygen to the brain; This is what is known as hypoxia .


  • Certain infections of the central nervous system , such as meningitis , are another possible cause of a coma. Although meningitis can occur in people of all ages, it is much more common in children.

Glasgow coma prognosis

The prognosis of a coma varies considerably between patients. It largely depends on the causes that have led to this situation, as well as the time the patient remains in a coma.

In general, those comas that occur as a result of intoxication by substances such as drugs have a very high recovery rate. Similarly, those comas that arise from trauma and head injuries have a higher recovery rate than those related to lack of oxygen.


In the healthcare setting, precision is of the utmost importance in determining the severity of different disorders. Thus, the Glasgow Scale makes it possible to diagnose with great precision and certainty patients who are in a coma or who have suffered some type of head injury, thus avoiding the use of ambiguous terms such as “the patient is drowsy.”

The Scoring Scale (Glasgow) assesses three key aspects and, furthermore, being a non-invasive tool, it can be used as many times as necessary to check the patient’s progress .

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Hello Readers, I am Nikki Bella a Psychology student. I have always been concerned about human behavior and the mental processes that lead us to act and think the way we do. My collaboration as an editor in the psychology area of ​​Well Being Pole has allowed me to investigate further and expand my knowledge in the field of mental health; I have also acquired great knowledge about physical health and well-being, two fundamental bases that are directly related and are part of all mental health.

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