Here is a really great article that defines the terms we have been discussing. I have copied it in its entirety. It also introduces a brand new term--
Minimally Conscious State.
Here's the link, if you want to access the site:
http://tinyurl.com/2k939
New Diagnostic Term Helps Clarify Prognosis, Treatment Decisions for TBI Patients
Correctly identifying a patient's level of consciousness following a traumatic brain injury (TBI) is an extremely important part of the evaluation and can be especially challenging in patients with prolonged impairment of consciousness. It is critical in formulating diagnosis and prognosis. It can increase or reduce the hope that family members maintain about their loved one's recovery. It contributes to treatment, rehabilitation and discharge decision-making. It can even be the deciding factor in life and death decisions, such as whether to continue or withdraw treatment.
Because there are so many medical, legal and ethical ramifications behind the correct identification of a patient's level of consciousness, it is important to be aware of progressive levels of consciousness, and how to recognize and define them. Further, it is essential that everyone is using accepted diagnostic terms in the same way to correctly identify a patient's state of consciousness. That is why a recent effort to develop a new diagnostic term--minimally conscious state (MCS)--to describe a well-recognized intermediate condition in the progression from unconsciousness to full consciousness has been so important. Awareness of the MCS and other conditions of impaired consciousness is of great significance in the continuing care arena because of the implications for decisions regarding assessment, level of care and treatment setting for patients with brain injury who may be recovering more slowly.
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MCS is defined as, a condition of severely altered consciousness in which minimal but definite behavioral evidence of self or environmental awareness is demonstrated.
As a backdrop, full consciousness may be defined as a person's awareness of his or her internal state and external world, integrated with a comprehensive sense of self, linked to a perspective of past and future. In between full consciousness and unconsciousness is a continuum of varying states of awareness and cognitive capacity. It should be noted that applying labels to the various levels of consciousness is difficult, owing to the fact that the boundaries between conditions may be somewhat arbitrary. That said, the medical community has for some time agreed on several terms to describe different levels of consciousness and cognitive capacity:
Brain Death
An irreversible condition of complete absence of brain function, including brain-stem function. A patient cannot survive in this condition without artificial supports, such as a respirator, and is considered clinically dead.
Coma
A state of unconsciousness in which a person shows no signs of eye opening or superficial arousal. When occurring as a result of acquired brain damage, coma is an acute or subacute condition that usually evolves to the vegetative state or higher level of consciousness within two to four weeks in patients who survive.
Vegetative State
In the vegetative state--a term that is sometimes deemed insensitive but an accepted medical term nonetheless--there are no signs of conscious awareness but the person does show signs of wakefulness, looking at times as if they are awake and other times asleep. They have lower-level brain function in the brainstem and other regions which allows for the potential of gross arousal and eye opening, but they do not have any significant functioning in the cerebral cortical areas to facilitate any awareness or thinking. The term permanent vegetative state has been used when this condition persists for an extended period of time (12 months for patients with TBI and 3 months for patients with nontraumatic forms of brain injury). Though deemed permanent, there have been isolated reports of patients recovering consciousness after these time periods so there is not absolute certainty in the permanence of the condition. The term persistent vegetative state is also frequently applied for those with this condition longer than a month. This term is so often misapplied and confused with permanence that it should probably be avoided.
Confusional State
This is a condition of greater cognitive awareness, more consistent responsiveness, but significant global cognitive dysfunction with severe impairments in attention and profound amnesia. For patients with TBI, this condition is often termed, post-traumatic amnesia (PTA), a period in recovery when a patient is unable to encode in memory any new information or experiences. In many cases the condition may be termed acute confusional state and the implication is that this is a temporary condition.
Dementia
When patients remain in a chronic state of global cognitive dysfunction, profoundly affecting multiple domains of intellectual ability, with severe effects on a patient's functioning and self care, the term dementia may be applied. The term is usually used for degenerative conditions such as Alzheimer's disease or vascular dementia, but it is also correctly used for patients with other brain disorders that cause chronic profound loss of cognitive function. Levels of conscious awareness may vary in patients with dementia but capacity for full self-awareness is reduced because of cognitive deficits.
As these terms have become better understood and accepted, and especially as the criteria and prognosis for the vegetative state were clarified, it became apparent that there was a gap in the nomenclature. Many patients display a clinical condition not fitting the criteria for the vegetative state or complete unconsciousness, yet these patients cannot be considered fully conscious, or at a level that terms such as the confusional state can be applied. The Aspen Neurobehavior Workgroup on impaired consciousness, headed up by Joseph T. Giacino, Ph.D., and comprised of representatives from neurology, neurosurgery (including Dr. Bryan Jennett of Glasgow, who coined the term vegetative state), physiatry, neuropsychology, nursing, allied health and bioethics, led the effort to introduce a new diagnostic term. The group concluded that there was a need for more precision in the diagnosis of different levels of impaired consciousness, and a need to distinguish patients who display subtle or inconsistent signs of conscious behavior. They recognized that the implications were far-reaching, particularly as relates to prognosis and treatment decisions. In fact, decisions regarding withdrawing fluid and nutrition, continuing medical or rehabilitative treatment, or managing pain and suffering might hinge on the differentiation of unconsciousness and minimal consciousness.
As a result of these efforts, the term Minimally Conscious State has been introduced. MCS is defined as,"a condition of severely altered consciousness in which minimal but definite behavioral evidence of self or environmental awareness is demonstrated." The diagnostic criteria for MCS include limited but clearly discernible evidence of self or environmental awareness demonstrated on a reproducible or sustained basis by one or more of the following behaviors.
Simple command-following
Gestural or verbal "yes/no" responses (regardless of accuracy)
Intelligible verbalization
Purposeful behavior, including movements or affective behaviors that occur in contingent relation to relevant environmental stimuli and are not due to reflexive activity.
The upper boundary of MCS, separating from higher levels of consciousness, such as the confusional state, is harder to demarcate precisely and a little more arbitrary in establishing. The Aspen Workgroup agreed upon criteria for the upper limit of MCS that include the ability to accurately convey "yes" and "no" responses to simple questions aor appropriately use objects (for instance, a comb or food utensils).
It should be noted that the incidence of MCS suggests that this is a syndrome which has been crying for attention. Dr. Stephen Ashwal and his colleagues at Loma Linda University have estimated that there are between 112,000 and 280,000 adult and pediatric patients in MCS; if accurate, these findings indicate that the prevalence of MCS in this country is eight times higher than VS.
Now that we have defined the term MCS and highlighted its position on the continuum of consciousness, the question of its importance must be addressed in greater detail. Our goal is to ensure that the term becomes adopted on a variety of fronts--legal, medical, ethical, research--because of the ramifications in these areas for TBI patients and their families.
The legal arena carries perhaps the most controversial ramifications. Over the last 20 years in particular, the courts have been asked to hear cases involving people with profound brain damage to decide whether families should be allowed to stop active treatment, including fluid and nutrition. In the 1960's and 1970s, the primary legal yardstick for stopping active treatment of a severely brain-injured patient was brain death. Upon this diagnosis, allowing a patient to die was deemed acceptable. In fact, brain-death became an acceptable criterion for defining death.
The legal challenges were extended in the 1980s to consider people who were unconscious and seemed firmly ensconced in that state yet able to live without cardiopulmonary support and not brain dead. The question was: Could they ever regain consciousness? Moreover, once they were in this state and recovery seemed hopeless, could a family withdraw treatment ethically and allow them to die? It has now become largely accepted in this country that if a person is in a permanent vegetative state from TBI or other cause, withdrawing treatment is allowable.
Given that this profound legal and ethical decision hinges on a diagnosis of unconsciousness without expectation of recovery, it is vital to properly identify the level of consciousness and establish an accurate prognosis.
Treatment options represent another area in which consciousness plays a major role. Many patients, following a traumatic brain injury (TBI), are cared for at the acute medical level as well as the acute rehabilitation hospital level. The majority of people in prolonged states of severely impaired consciousness are transferred to nursing homes because they are unable to participate in an active rehabilitation program. While some do come to acute rehabilitation, the greatest number go from acute care hospital to skilled nursing facilities. For these people, there are significant continuing care decisions that must be addressed in terms of diagnosis and prognosis: do these people need a more specialized medical rehabilitation effort or additional diagnostic workup to establish their functional level? For patients who are in this state and have been in nursing homes for an extended period of time, it is critical to ensure that they were properly diagnosed and that subsequent improvement in consciousness has not been missed. The distinction between someone with no signs of consciousness and someone who has minimal consciousness may go unnoticed unless caretakers are watching carefully over extended periods of time for subtle or infrequent signs of conscious behavior. Again, prospects for recovery and treatment choices differ based on this distinction.
One example affecting treatment decisions within the ethical and medical arena is the issue of pain perception. It is generally accepted within medical circles that patients who are unconscious do not consciously feel or suffer from pain. They exhibit reflexive actions to certain stimuli that may cause automatic motor responses. These may give the appearance of pain perception but the messages do not reach the pain perception and cognitive awareness part of the cerebral cortex to allow pain perception or suffering. Recent functional brain imaging studies support this conclusion for patients in the vegetative state. Yet if a person is minimally conscious, there is a definite potential that they may experience pain at some level; consequently, treatment of pain might become a priority once it is established that a patient has crossed the threshold between the vegetative state and the minimally conscious state.
On the assessment side, it is important for clinicians to watch for signs that a person with profound brain damage who has not demonstrated any purposeful behavior, may be starting to follow simple commands, or to signal communication in some manner - perhaps as rudimentary as eye blinking. This may take a more concentrated and organized diagnostic effort to present stimuli and look for responses that appear to be consciously purposeful and contingent on the interaction. It is often difficult to determine if inconsistent or very limited motor responses are automatic, reflexive or volitional and conscious at some level. Early signs of more purposeful behavior include visual fixation and tracking of an object, or movement of a limb in a more controlled and goal-directed fashion. Once the early signs of consciousness become apparent, it is incumbent on the treatment team to try to establish some system of communication. Sometimes this involves a simple motor signaling system (e.g., eye gaze or finger signals) in patients who are mute or who have limited movement.
It is important to note that many patients not only exhibit profoundly impaired consciousness, but they may have profoundly impaired movements as well. Severe, diffuse or multifocal brain damage that affects consciousness and cognition may also affect motor control and sensation. Patients may also have a spinal cord injury, damage to peripheral nerves or orthopedic injuries that limit movement. Whether patients' lack of cognitive behavioral responses is the result of impaired consciousness or cognition or impaired motor abilities or some combination of these is a frequent problem that challenges diagnostic assessment. In addition, there is a subgroup of patients that have some level of consciousness and the preserved potential to move, but they remain largely mute and immobile, largely because they have lost the neural mechanism to initiate and drive movement or speech. This condition has been termed akinetic mutism.
There are other conditions that produce what we call a "locked-in syndrome": a state where the patient is fully consciousness but cannot move or talk. Patients with damage to the motor portion of the pons in the brainstem and patients with the most severe forms of the Guillain Barre Syndrome are examples of this condition of loss of voluntary motor control in the setting of preserved consciousness. This condition needs to be distinguished from those that produce a lack of movement because of impaired consciousness or a mix of impairments in consciousness and motor control. It must also be recognized that patients who at first present with unconsciousness may evolve in their recovery to a condition of restored consciousness with profound loss of motor control, for example, relatively locked-in.
The bottom line is relatively clear: It is critical to correctly identify the level of consciousness in patients with TBI for a variety of ethical, legal, and medical reasons. The addition of this new term--Minimally Conscious State--to the nomenclature of medical terms that define impaired consciousness will help in establishing proper diagnosis, prognosis and treatment planning for patients with severe TBI. It also will facilitate research efforts towards a better understanding of brain functioning, prognosis and treatment of conditions of impaired consciousness, which will certainly have major implications for the continuing care arena.
Dr. Douglas A. Katz is a neurologist with training in behavioral neurology, who has been working in neurorehabilitation, with a primary interest in patients with traumatic brain injury. He has been at HealthSouth Braintree Rehabilitation Hospital for more than 16 years where he is medical director of Brain Injury Programs. He is presently with Boston University Neurology Associates and he is Associate Professor of Neurology at Boston University School of Medicine. He has numerous publications and frequently presents at national and international meetings, particularly on topics related to Traumatic Brain Injury.
Would you like to comment?
) This is such a serious subject and I think a very important one. I have stated before that I talk to my coffee pot so I am sure I'll be talking to brain dead patients. Comatose ones, of course, but that's an entirely different thing as has been stated numerous times.
