Minimally conscious state: symptoms and causes

Perceiving our environment and ourselves, understanding it and interacting with it are essential skills that we possess thanks to our state of consciousness. When it remains intact, we are perfectly capable of dealing with the environment and responding to external stimuli and demands.

However, this state can be altered by a series of damage to the nervous system. Among many other conditions, these damages can cause the so-called minimally conscious state, which we will talk about throughout this article.

• Related article: "The 6 levels of loss of consciousness and associated disorders"

What is the state of minimal consciousness?

Formerly known as the "least responsive state", the state of least consciousness consists of a neurologically based alteration whereby the person is submerged in a serious situation of their level of conscience. This disposition of the person is categorized within the diagnostic category of disorders of consciousness, among which are coma, drowsiness or stupor.

By consciousness we understand the state by which the person maintains the knowledge of himself and his environment, together with the ability to interact with him.

Taking this into account, we can understand that the state of minimum consciousness is about a disposition or condition of the person in which the consciousness is kept at such low levels that it does not allow you to communicate or maintain an interaction with your environment in an optimal way and functional.

Nevertheless, In this type of neurological disorder, people show minimal but perceptible signs of behavior and response to external stimuli. These reactions to the environment occur through eye tracking, basic gestural responses or a kind of intelligible language.

As for the duration of this state of minimal consciousness, it can become permanent or permanent. Furthermore, in cases where it is a temporary state, the recovery of a state of minimal consciousness is an arduous process in which the possibilities for improvement are limited.

Although the incidence of this disorder is not exactly known in Spain, it is estimated that between 30% and 40% of patients with severe brain injuries present alterations in the level of conscience.

The etiopathogenesis of this minimal state of consciousness, as well as many other disorders related to it, is to be found a series of damage or injuries to different areas of the brainstem, as well as various structures such as the thalamus wave association cortex.

What symptoms does it present?

At the level of neurological functioning, patients in a minimally conscious state see brain metabolic activity diminished, down to around 20 to 40%. Despite these very low levels of brain activity, the body manages to maintain automatic functions to sustain the life of the person.

This means that despite brain damage the cardiac functions, as well as the respiratory capacity manage to stay active, working the same as in a completely healthy person.

This state of minimal consciousness is characterized by the person can make small barely understandable verbalizations, basic gestural reactions and execute little elementary instructions.

However, for the diagnosis of a minimum state of consciousness to be established, the person must present at least one of the following signs or behaviors:

• Response to simple commands.
• Verbal or non-verbal responses of yes and no.
• Incomprehensible verbalizations, with or without the presence of a stimulus that causes them.
• Basic gesturing in response to oral questions.
• Visual fixation and visual tracking of a stimulus.
• Stereotyped movements in response to an external stimulus.
• Emotional responses, such as laughing or crying, congruent with the stimulus.
• Perception of pain and location of painful stimuli.
• Touching and holding small objects.

Differences with coma and vegetative state

As mentioned above, the state of minimal consciousness is categorized within the disorders of alteration of consciousness. These disorders include coma and vegetative states, and although there are abnormalities in the level of consciousness in all of them, there are also significant differences.

While in the first the person has the ability to respond and react through basic expressions, in coma there is no possible reaction. The person maintains basic functions but neither does he keep his eyes open, nor does he express any type of response to stimuli, so it is considered that there is not the slightest level of conscience.

If this state of coma lasts for more than four weeks, it is considered a vegetative state, in which basic motor reactions caused by brain stem reflexes may appear.

• You may be interested: "The Glasgow Coma Scale: How to Measure Unconsciousness"

What are the causes?

Like the rest of disorders that affect consciousness, the main cause is found in a lesion in the central nervous system, specifically in a structure known as the ascending lattice system, which controls the levels of alertness and consciousness.

There are a multitude of conditions, both organic and external, that can generate a minimum state of consciousness. Some of them are:

1. Organic causes

• Autoimmune diseases that cause inflammation of the nervous system.
• Ischemic accidents or hemorrhagic strokes.
• Primary and secondary neoplasms.
• Anoxic encephalopathies.

2. External causes

• Meningitis or infectious diseases.
• Head injuries.
• Encephalopathies due to toxic agents.
• Radiation encephalopathies, electrocution, hyper or hypothermia.
• Treatment and prognosis.

Due to the characteristics of this condition, an effective intervention protocol that alleviates the minimal state has not yet been established. However, a series of actions can be carried out depending on the severity of the patient's condition.

At the beginning of the disease it is of vital importance to stabilize the vital signs of the person, and then try to recover the cognitive functions that remain in the person. This is done through multisensory stimulation programs and neurological activation exercises.

Regarding the prognosis of patients in a state of minimal activation, they can remain in it for years, which may involve serious and irreversible brain injury. However, there are cases in which the person achieves a certain degree of progressive or gradual recovery.