He State of minimum consciousness or Minimally conscious state (MCS) , In English, it is a neurological disorder in which there is a serious alteration of the level of consciousness (Spanish Federation of Brain Damage, 2014).
In this type of pathology there is a minimal, but detectable presence of consciousness, both of oneself and of environmental circumstances (Spanish Federation of Brain Damage, 2014).
In the state of minimal consciousness, some of the most characteristic features are: ocular fixation or follow-up, gestural or vernal responses of yes / no, Execution of simple orders, motor and emotional responses and an intelligible language (Spanish Federation of Brain Damage, 2014).
Specifically, the state of minimal awareness, is encompassed within the disorders of consciousness (alteration of the level of consciousness, Obtundation , stupor, coma , Etc.) and to an alteration of the content of consciousness (temporal or spatial disorientation or difficulty of maintaining the Attention).
With regard to statistical data, approximately 30% to 40% of people with brain damage have conscience level. . The causes of this type of alterations can be diverse, they can originate by injuries at focal or diffuse level, concretely in he brainstem Or related structures, such as Thalamus And association cortex (Mais-Sesé et al., 2015).
The state of minimum consciousness can be transitory or permanent. Although not known exactly the volume of patients present a recovery Functional state of this state, in most cases, the time period of the state of minimum consciousness is long and therefore, the probability of Functional improvement is scarce (Brain Foundation, 2016).
What is a Conscious Disorder?
Throughout the evolution of the scientific and medical literature, the term conscience has generated a great controversy. At present, awareness can Defined as a state in which a particular individual has knowledge of himself and his environment (Puerto-Gala et al., 2012).
In addition, in the definition of consciousness, consideration of the terms of arousal and awarness are essential:
- Arousal : By this term we refer to the alert level, understood as"being aware"and is responsible for maintaining the capacity Of being awake and regulating sleep-wake rhythms (Mais-Sesé et al., 2015).
- Awareness : With this term, on the other hand, we mean alert, understood as"being conscious"and refers to the capacity that We have to detect the stimuli coming from the environment and be aware of them and of ourselves (Más-Sesé et al., 2015).
When we refer to an alteration of consciousness, we can refer to both an alteration in the level of surveillance, and an alteration in our Ability to interact with the environment (De Castro, 2008).
However, the absence of response is not always comparable to a total loss of consciousness. Therefore, awareness or level of activation Can be represented in a continuum, from a mild state to a severe state of total absence of response. Thus, we can distinguish intermediate states Between wakefulness (alert) and the state of total absence of response (coma) (Puerto-Gala et al., 2012).
What is the state of minimum awareness?
The term State of minimum consciousness Which currently replaces the term" Minimal response status ", Was defined With the American Congress of Rehabilitative Medicine in 1995 (Laureys et al., 2001).
This is used to catalog patients who are not able to communicate or follow instructions in an optimal and functional way, but show Evidence of behavior inconsistent but detectable to external stimulation (Laureys et al., 2001).
How many people are in a state of minimum awareness?
In Spain, the concrete figures of people in a state of minimum consciousness are not known with exactness.
In the United States, it has been estimated that between 112.00-180,000 adults are in a state of minimum awareness and between 10,000 and 25,000 in Persistent vegetative state (Volaric and Mellado, 2003).
What are the signs and symptoms of the state of minimal awareness?
Patients who are in a state of minimal awareness may show visual fixation and emotional or motor behavior contingent upon Presence of specific stimuli (Laureys et al., 2001).
Although in this state, patients are not able to communicate functionally, they are able to follow some simple instructions, perform Compressible verbalizations (Grosseries et al., 2011), gestural or verbal yes / no responses (Laureys et al., 2001).
Sometimes they may show sudden crying by the presence of familiar voices and also smiles or laughter (Grosseries et al., 2011).
Although all these signs are different from the reflex responses, it will be necessary for these behaviors to reproduce frequently and contingently to Different environmental demands.
As regards the neurobiological level, in the state of minimal consciousness, the cerebral metabolic activity was reduced by about 20-40% (Laureys et al. 2004; Grosseries et al., 2011). In addition, the autonomic functions are maintained (respiratory breathing, cardiac, etc.).
Classification for the state of minimum consciousness
In people who are in a state of minimum awareness it is possible to detect different levels of severity depending on the level of Surveillance and knowledge of the environment and the observable signs it shows (International Brain Injury Association, 2021):
- MCS (-) : State of minimum deep consciousness. In this state can be observed minimum levels of interaction characterized Mainly due to the presence of non-reflexive movements: voluntary orientation to noxious stimuli, follow-up ocular movements and search of Environmental stimuli (International Brain Injury Association, 2021).
- MSC (+) : State of minimal awareness, characterized by: follow-up of orders, intelligible verbalizations or responses Or verbal, yes / no (International Brain Injury Association, 2021).
What is the cause of the state of minimal awareness?
Lesions in the ascending reticular system
In general, all disorders of consciousness occur as a result of lesions at the level of the central nervous system.
Specifically, lesions in the ascending reticular system ( SRRA ), Will seriously damage alert levels and Ability to stay awake (De Castro, 2008).
The ability of human beings to think, perceive, respond to stimuli is due to the functioning of the cerebral cortex, however It is not going to show an efficient execution if the participation of other structures and without the maintenance of an adequate state of alert. When We are sleeping, it is necessary for the RAAS to activate the cortex to awaken us (Hodelín-Tablada, 2002).
Any injury to the structures that make up it will lead to a decrease or loss of the level of consciousness (Castro, 2008). Consciousness is Impossible if the SRRA is seriously injured or harmed (Hodelín-Tablada, 2002).
Etiological Causes
A multitude of causes have been identified that can lead to injury and damage to the brain. Among the most common are:
Injuries caused by external agents
- Toxic encephalopathy: drugs, drugs and other chemical substances
- Encephalopathy by physical agents: ionizing radiation, electrocution, hyperthermia or hypothermia.
- Diseases of infectious type: Meningoencephalitis
Injuries caused by endogenous causes
- Hemorrhagic or ischemic stroke
- Anechoic encephalopathy: due to various causes such as cardiorespiratory arrest.
- Primary or secondary neoplasms
- Autoimmune inflammatory diseases.
How is the state of minimal awareness diagnosed?
To determine the level of consciousness, the possible presence of anatomical lesions and each of the criteria detailed above are usually Various diagnostic methods.
To establish the future prognosis and consequently the relevant neurological rehabilitation, it is fundamental to make a differential diagnosis between The different altered states of consciousness (Grosseries et al., 2011).
The fundamental method for identifying signs of consciousness is clinical observation. In patients with altered states of consciousness in the acute phase, It is crucial to obtain all the information about their cognitive progress (Grosseries et al., 2011).
To examine this area, the use of diagnostic scales, based on behavioral evaluations, is frequent.
Some of the most used scales are:
- Glasgow Coma Scale (Glasgow Coma Scale- GCS).
- Revised Coma Recovery Scale (The Coma Recovery Scale-Revised -CRS-R-).
- Lack of response scale (The Full Outline of Unresponsiveness -FOUR-).
- Wessex Brain Injury Matrix (Wessex Head Injury Matrix -WHIM-).
However, purely behavioral evaluation does not offer us a definitive diagnostic judgment about the presence or absence of signs of consciousness.
It is possible that by using these methods exclusively, erroneous differential diagnoses and even false positives can be performed, since the Absence of response is not always indicative of absence of consciousness and on the other hand, motor responses can not be interpreted as Unequivocal signs of consciousness, since they may constitute an erroneous interpretation of spontaneous movements and reflexes.
Therefore, it is essential to use other methods, such as activity and image, to carry out an adequate and accurate differential diagnosis. cerebral.
- Electroencephalography : Is a non-invasive method that records the electrical activity of the brain through electrodes that are placed On the scalp of the person. It allows us to identify alertness or surveillance, and abnormal activities such as seizures. I also know Used to confirm the diagnosis of brain death, identifying the complete absence of brain activity (Grosseries et al., 2011).
- Evoked Potentials : The evoked potentials technique examines the patient's cognitive function through electrical activity With the use of electroencephalography (Grosseries et al., 2011).
- Functional brain imaging: The studies of Positron emission tomography and of Functional Magnetic Resonance Allow to obtain Information about brain function through analysis of brain metabolism, blood flow, and oxygen consumption (Grosseries et al., 2011).
In the case of the state of minimum awareness there is a wide variety of diagnostic criteria that may differ depending on the organization or entity Which elaborates them, some of them are (Noé-Sebastián et al., 2012):
Criteria of minimum response status of the American Congress of Physical Medicine and Rehabilitation (1995)
- Presence of a response or behavior consistent with a simple order, question, gesture or external stimulus.
- The answer must be clearly congruent. There must be evidence that such responses occur as a consequence of an order, question, or
stimulus.
- The response must be observed on more than one occasion during the evaluation or evaluation.
Minimally Consciousness Criteria of the Aspen Neurobehavioral Conference Workgroup (1995)
- Answer walk simple orders.
- Presence of manipulation of objects.
- Verbal or gestural responses of yes / no.
- Verbalization intelligible.
- Presence of stereotyped movements (blinking, smiling, etc.) in response to a stimulus.
Criteria of state of minimum awareness and emergency of said state of the Aspen Neurobehavioral Conference Workgroup (2002)
State of minimum awareness:
- Answer walk simple orders.
- Presence of manipulation of objects.
- Verbal or gestural responses of yes / no.
- Verbalization intelligible.
- Behaviors directed at a goal or affective responses in response to relevant stimuli:
- Laughter and / or crying in the presence of relevant visual or verbal stimuli.
- Gestures or verbalizations in response to questions of linguistic content.
- Location and scope of objects.
- Handle (touch or hold) objects properly according to their dimensions.
- Visual fixation and tracking of stimuli.
Treatment for the state of minimum consciousness
Although there is no concrete therapeutic measure that provides a cure to a state of minimum awareness, in all cases, the measures that are Will depend on both the severity of the brain lesions that are present and the future prognosis.
In the initial phases, prevention of complications and maintenance of body integrity is essential. In this phase, All pharmacological interventions that stabilize the vital signs of patients.
As soon as the patient is medically stabilized, the use of rehabilitative neuropsychological measures through Multisensory stimulation programs and recovery of residual cognitive functions.
Specifically, some specialists point out that it is essential to make efforts to establish communication and functional interaction of the patient with the environment.
What is the prognosis of patients in a state of minimum awareness?
In many cases, the person affected remains for years in a state of minimum awareness, mainly due to the presence of serious brain damage And irreversible.
However, there are cases in which patients are able to achieve functional communication, follow progressive instructions or employ Different objects. When the complexity of the patient's responses is increasing, we may consider that he is in an emergency phase of the State of minimum consciousness.
In cases of recovery, those affected usually show a period of confusion and progressive functional recovery.
References
- BF. (2016). Minimally Conscious State . Retrieved from Brain Foundation.
- FEDACE. (2014). Coma, Unanswered Vigil Syndrome and Minimal Consciousness . Retrieved from"Spanish Federation of Brain Damage".
- Grosseries, O., Vanhaudenhuyse, A., Bruno, M., Demertzi, A., Schnakers, C., Boly, M., et al. . . Laureys, S. (2011). Disorders of Consciousness: Eat,
Vegetative State and Minimally Conscious States. In S. o. Consciousness, Cvetkovic, D.; Cosic, I.; (Pages 29-55). The Frontiers Collection. - Nisa Hospitals. (2013). Unanswered Vigilance Syndrome and Minimal Consciousness Status . Obtained from Neurorehb.
- IBIA. (2012). UNRESPONSIVE WAKEFULNESS SYNDROME AND MINIMALLY CONSCIOUS STATE: TOWARDS A BETTER UNDERSTANDING OF DISORDERS OF CONSCIOUSNESS .
Obtained from International Brain Injury Association. - MSKTC. (2013). Facts about the Vegetative and Minimally Conscious States after Severe Brain Injury . Obtained from Model Systems Knowledge Translation Center.
- Nisa, H. (2015). State of Minimal Consciousness . Obtained from Neurorehb.
- Volaric, C., & Mellado, P. (2013). State of Minimal Consciousness. Neurology Notebooks .