State of minimally consciousness: evolution, awakening, rehabilitation
The ‘state of minimally consciousness’ (also called ‘minimally conscious state’) refers in medicine to an altered state of consciousness defined by minimal behaviour that demonstrates an awareness of self and/or environment, albeit less than normal
Diffusion of the minimally consciousness state
The incidence of the vegetative state is estimated at 0.7-1.1/100,000 inhabitants; the prevalence is 2-3/100,000 inhabitants.
Approximately one third of vegetative states are of traumatic origin.
Of the two-thirds of non-traumatic origin (ischaemic or haemorrhagic brain stroke, encephalitis, anoxia) almost 50% are brain anoxia.
What is consciousness?
Ever since man began to reason about himself, the answers to this question have been the most varied, depending on the field, e.g. religious or philosophical.
Neurologically speaking, consciousness is that component of the human being characterised by two portions:
- vigilance: it is characterised by a state of wakefulness that is not necessarily associated with awareness of what is happening in the world around us;
- awareness: consists of awareness of the world around us and, in the most evolved state, of one’s own being.
In the healthy subject (person with complete consciousness) both components are normal, whereas in the patient in a minimally conscious state these components are altered and temporally inconstant: awareness may fluctuate throughout the day.
A minimally consciousness state can be of two types:
- acute minimally conscious state: more easily reversible;
- chronic minimally conscious state: difficult for the patient to return to a state of full consciousness.
Causes of the minimally consciousness state
Among the most common causes are cerebral strokes and traumas to the brain resulting in coma, of which the state of minimally consciousness may represent the evolution.
The anatomical correlates of consciousness are identified with:
- the ascending reticular substance, which is mainly responsible for the level of consciousness;
- the encephalic hemispheres, higher cognitive functions and seat of content.
Any physical-chemical noxiousness that directly or indirectly affects these structures is capable of causing coma and the subsequent possible evolution into a vegetative or minimally conscious state.
Coma, vegetative state and minimally consciousness state
The minimally conscious state is considered as a possible evolution of the comatose state, as an alternative to the vegetative state, or as a possible evolution of a vegetative state.
Generally, vegetative states or states of minimally consciousness appear approximately 30 days after the onset of coma, but this is by no means a fixed rule.
The exact definition of the term has always been much debated in the scientific literature, especially given the aspects in common with the vegetative state, with which it shows minimal differences, which however become important when it comes to prognosis (better in the minimally conscious state than in the vegetative state) and in the treatment to be followed; moreover, compared to the vegetative state, the responses of the subject with minimal consciousness to treatment are on average better.
From vegetative state to minimally consciousness state: the Coma Recovery Scale-Revised (CRS-R)
Distinguishing the state of minimally consciousness from the vegetative state is fundamental for planning a personalised rehabilitation project oriented towards the maximum possible functional recovery, despite the severe brain injury.
The assessment of the transition to the minimally conscious state is carried out by the professionals of the multidisciplinary team that follows the patient, for whom it is essential to speak a common language, i.e. to use shared assessment tools of defined interpretation.
Among the most widely used is the Coma Recovery Scale-Revised (CRS-R), codified in the USA for over a decade, for some years now also available in the Italian version, approved by SIMFER (Italian Society of Physical Medicine and Rehabilitation) and SIRN (Italian Society of Neurological Rehabilitation).
Characteristics of the patient with minimal consciousness
The subject with minimal responsiveness
- has his eyes open spontaneously or – if he keeps them closed – opens them if stimulated appropriately;
- looks the examiner in the face;
- follows a visual stimulus (e.g. a light) with his gaze;
- generally does not speak or makes insignificant sounds;
- can give intentional responses after simple verbal command or on imitation, e.g. shake hands, move a finger;
- can make simple purposive movements including affective movements or behaviour generally has the ability to swallow or – if he has lost it – potentially has the ability to regain it.
Diagnosis is possible through medical examination (anamnesis and objective examination).
In addition, it is possible to assess through functional magnetic resonance imaging the subject’s response to familiar cues, such as calling him by name.
Therapy in the minimally consciousness state
In the minimally conscious state, in addition to possible damage to the brain that has led to coma, there is a deficiency of dopamine, an important neurotransmitter for the nervous system.
Some drugs such as dopamine receptor agonists are currently being tested.
In a promising 2009 study on a single patient, Fridman et al. showed how through an administration of apomorphine, a dopamine agonist, the patient regained the ability to move his limbs on demand and answer yes/no questions, which he was unable to do prior to the administration of apomorphine.
Thereafter there was a complete recovery of consciousness functions and a substantial recovery of functional abilities, sustained even after apomorphine was discontinued.
At the maximum dose, mild dyskinesia (movement alterations such as rigidity, difficulty initiating movement, motor slowing and involuntary and/or excessive movements) was observed.
Among researchers, the chronic administration of analgesic substances is currently discussed, as these patients may experience pain as they have a minimum of consciousness left.
Minimally consciousness state: evolution and prognosis
Patients in a chronic minimally conscious state are unlikely to have much improvement over time, unlike those in an acute minimally conscious state who can actually return to a condition close to normal.
Unfortunately, it is very difficult to make predictions as to what the evolution of a patient in a minimally conscious state might be: in many cases the damage is irreversible, but one case has been followed in the literature who ‘woke up’ many years after the trauma (Terry Wallis).
Worsening elements of the prognosis are:
- high fever;
- decubitus injuries;
- previous tracheotomy operations;
- recurrent infections;
- initial disabilities (before the event);
- poor general health of the patient (e.g. hypertensive, obese or diabetic);
- advanced age of the patient.
Elements that improve prognosis are:
- love and warmth of the patient’s friends and relatives;
- passive mobilisation of the patient;
- absence of decubitus injuries;
- assiduous medical supervision;
- absence of initial disability (before the event);
- good general health of the patient (normal weight, fit);
- younger age of the patient.
In minimally conscious patients, although there is a rudimentary recovery of consciousness, severe cognitive and motor deficits persist with inability to perform activities of daily living, communicate adequately and give consent to treatment.
Sphincter incontinence and feeding generally administered by gavage mean that these patients are completely dependent on family members.
The acute patient who returns to a state of full or partial consciousness can improve physically through specific rehabilitation interventions.
Resuscitation and intensive care in the acute phase of brain injury are extremely important for prognosis and are in effect the first phase of rehabilitation of the traumatised head and the incidence and severity of late problems depend largely on early treatment choices.
Treatment and rehabilitation
The rehabilitation approach of the physiatric-physiotherapic-nursing team must first of all include the assessment of brain damage by identifying through various instrumental examinations its type, extent and site, thus highlighting intra- and extracerebral haematomas, cerebral softening, oedema with consequent endocranial hypertension and transtentorial herniations.
Any rehabilitative treatment must circumscribe the primary damage, preventing its extension to neighbouring or dependent functional areas, prevent secondary damage, prevent tertiary damage, diminish pathological potential and enhance health potential and must also necessarily include not only the patient, but also the health, family and social environment.
In the acute phase, treatment must be aimed at promoting awakening with
- sensory and sensory stimuli, at first elementary and then more sophisticated in relation to the patient’s premorbid personality;
- neuromuscular facilitation techniques, which through the stimulation of esteroceptors and proprioceptors reflexively create the conditions to facilitate or inhibit the contraction of certain muscle groups;
- correct postures, correct posture changes and correct movements.
To this end, it is considered useful to proceed with rehabilitative treatment through techniques aimed at evoking residual potentials to the maximum for a better adaptation of the individual to himself and the world.
Unthinkable progress can thus be achieved through the plasticity of the still intact central nervous system.
However, this is only possible if the environment is early, richly and adequately stimulating.
The aim of treatment is based on the reconstruction of the functional brain-environment integrity by means of correct, intense, continuous and frequent environmental stimuli, designed to evoke the patient’s full developmental potential, starting from the functional level remaining after the traumatic event in the various areas so that his or her sense-motor activities are always controlled, enriched and adapted.