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

However, this state can be altered by a series of damages to the nervous system. Among many other conditions, this damage can cause the so-called state of minimal consciousness , which we will discuss throughout this article.

What is the state of minimal consciousness?

Previously known as the “state of minimal response”, the state of minimal consciousness consists of a neurological base alteration by which the person is immersed in a serious situation of his level of consciousness. This disposition of the person is categorised within the diagnostic category of disorders of consciousness , among which are coma, obnubilation or stupor.

By consciousness we mean the state by which a person retains knowledge of himself and his environment, together with the ability to interact with it.

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

However, in this type of neurological disorder people show minimal but perceptible signs of behaviour and response to external stimuli. These reactions to the environment are given through ocular monitoring, basic gestural responses or a kind of intelligible language.

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

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

The etiopathogenesis of this minimal state of consciousness, as well as many other related disorders, is found at a series of damages or injuries in different areas of the brain stem, as well as in various structures such as the thalamus or the association bark.

What symptoms do you have?

At the level of neurological functioning, patients in a state of minimal consciousness see their brain’s metabolic activity reduced to around 20-40%. Despite these reduced levels of brain activity, the body manages to maintain automatic functions to sustain the person’s life.

This means that, despite the brain damage , the heart functions, as well as the breathing capacity, manage to remain active , functioning as in a completely healthy person.

This state of minimal consciousness is characterized by the fact that the person can carry out small verbalizations that are barely understandable, basic gestural reactions and execute small elementary instructions.

However, in order for a diagnosis of minimal consciousness to be established, the person must exhibit at least one of the following signs or behaviors:

  • Response to simple commands.
  • Verbal or non-verbal answers of yes and no.
  • Incomprehensible verbs , with or without the presence of a stimulus that provokes them.
  • Basic management 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 altered consciousness. Among these disorders are coma and vegetative states, and although in all of them there are anomalies in the level of consciousness, there are also significant differences.

While in the first one the person has the capacity to respond and react by means of basic expressions, in the coma state there is no possible reaction . The person remains with the basic functions but neither keeps the eyes open nor expresses any kind of response to stimuli, so it is considered that there is not the slightest level of consciousness.

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

What are the causes?

As with all other disorders affecting consciousness, the main cause is found in an injury to the central nervous system, specifically in a structure known as the ascending reticular system , which controls levels of alertness and consciousness.

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

1. Organic causes

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

2. External causes

  • Meningitis or infectious diseases.
  • Head trauma.
  • Toxic agent encephalopathies .
  • Radiation encephalopathies, electrocution, hyper or hypothermia.
  • Treatment and prognosis.

Due to the characteristics of this condition, an effective intervention protocol that refers to the state of minimal has not yet been established. However, a number of actions can be taken depending on the severity of the patient’s condition.

At the beginning of the illness it is of vital importance to stabilize the person’s vital signs, and then to try to recover the cognitive functions that remain in the person . This is done by means of multisensory stimulation programmes and neurological activation exercises.

As for the prognosis of patients in a state of minimal activation, they may remain in it for years, which may imply serious and irreversible brain damage . Nevertheless, there are cases in which the person achieves a certain degree of progressive or gradual recovery.