For Personal Injury lawyers who do not specialise in catastrophic injury, the relatively new term “minimally conscious state” may cause confusion1.
Just as many physicians will at some stage of their career manage a patient with catastrophic brain damage2, most Personal Injury litigators will at some time need to familiarise themselves with the distinctions that follow.
For severely brain injured clients, life expectancy for purposes of Quantum of Damages will be determined by the quality of evidence that medical expert opinion can provide.
However, the litigator who is thoroughly versed in the strengths and weaknesses of the research data and the changing concepts will be better placed to maximise his/her client’s position.
Brain death means the permanent and complete absence of all brain functions.
Life can be maintained temporarily only with total life-support systems.The 3 remaining states may be transient phases of recovery to full consciousness, or they may be permanent.
In coma there is deep unconsciousness lasting at least an hour, and arousal is not possible.
At least some vital functions of the brainstem persist, and life can be sustained with varying degrees of life-support systems.
The persistent vegetative state differs in that there are periods of eyes-open wakefulness, even though there is no consciousness.
Practice PointThough both are unconscious states, Persistent Vegetative State differs from Coma in that there are periods of waking |
The condition was defined by a 1994 consensus statement of a multi-society task force3,4.
In the same year, it was suggested5 [Full text] , on the basis of a high profile medicolegal case, that the condition arose out of disproportionate damage to the thalamus in the brainstem.
In the minimally conscious state, patients show some awareness by purposive verbal or nonverbal communication in response to verbal request1.
The terminology minimally conscious state was introduced6 in 1997 to replace the less accurate term minimally responsive state, and most of the clinical research literature has been published since 2002.
he Aspen Work Group defines minimally conscious state as "a condition of severely altered consciousness in which minimal, but definite, behavioral evidence of self or environmental awareness is demonstrated."
The condition is believed to be 5-8 times as common as persistent vegetative state.
It may be transient but if persistent after TBI is considered permanent at a year.
Practice PointMinimally Conscious State - at least 1 of1. Verbalises or gestures “yes” and “no” 2. Verbalises intelligibly 3. Other specified purposeful behaviour |
In summary,
brain death = no brain function
coma = some basic brain function
+ periods of waking = persistent vegetative state
+ purposive response = minimally conscious state
Locked-in syndrome7 [Full text] superficially resembles minimally conscious state.
However, there is total awareness, and it is the paralysis of all voluntary muscles except those producing eyelid and vertical eye movements that all but limits effective communication.
Practice PointIn locked-in syndrome, there is full consciousness but total paralysis except for eye movements |
Diagnostic Error
Distinction from persistent vegetative state is difficult but crucial for decision making.The distinction between persistent vegetative state and minimally conscious state causes the greater medical challenge8 [Full text] .
Because the persistent vegetative state is almost always9 [Full text] permanent a year after brain trauma4, it is medically and medicolegally essential to know whether life-support can be withdrawn9 [Full text] .
Even those few care-givers who have considerable experience with the persistent vegetative state cannot by means of a single bedside assessment determine that consciousness is absent10,11 [Full text] .
That determination should be made by prolonged multidisciplinary observation.
Prognosis
Among a group of adults who were in a persistent vegetative state a month after Traumatic Brain Injury, a third were dead by 1 year, nearly a half remained in a persistent vegetative state or were severely disabled, and only 7% had made a good recovery4.
Among a smaller group of children, recovery of consciousness was somewhat more common, but degrees of disability were similar.
Life expectancy in minimally conscious state depends on causation and degree of mobility.In comparison with coma and persistent vegetative state, the life-expectancy of patients in a minimally conscious state may be much greater.
Children in a minimally conscious state as a result of Traumatic Brain Injury generally survive longer than those with other causes - non-traumatic brain injury, genetic and degenerative disorders12.
However, at least in children, the presence or absence of mobility is the crucial determining factor for longevity12: there was little survival difference between persistent vegetative state and immobile minimally conscious state.
Practice PointIn comparison with persistent vegetative state, life expectancy for minimally conscious state is considerably better only for those that have some mobility |
Mobility means some ability to roll, sit, use arms or hands, or communicate nonverbally.
For example, of mobile minimally conscious 3 year-olds, 81% were still alive 8 years later.
Copyright © 2008 Electronic Handbook of Legal Medicine