New Neurologic Study: What is its Medical and Ethical Significance?
Read this science article in today's issue of the New York Times. It describes a study published in the current February 2005 issue of the journal Neurology. The study involved testing for metabolic brain activity using MRI imaging on two men who had traumatic brain injury and were in a "minimally conscious state"(MCS)(1) and comparing the responses to various stimuli with normal men and women. What was found was that there was evidence, on exposure to a recording of a familiar voice speaking, of patterns of metabolic activity in the temporal lobes of the traumatized patients that was similar to those of the normal subjects. By the anatomical location, the study suggested that there was active processing of language there possibly similar in some respects to normals. It is not clear what this all means but the New York Times article provides quotes from specialists who wonder if patients in MCS might be able to hear those who speak to them and may have some understanding though they may not be able to express what they hear. Also the experts wonder if this kind of MRI study technique may lead to more definitive diagnosis of the degree of neurologic impairment present beyond simple observation of behavior. The New York Times article relates the comments of the experts: " But they said the study did open a window on a world that has been neglected by medical inquiry. 'This is an extremely important work, for that reason alone,' said Dr. James Bernat, a professor of neurology at Dartmouth.
Dr. Bernat said findings from studies like these would be relevant to cases like that of Terri Schiavo, a Florida woman with brain damage who has been kept alive for years against her husband's wishes. In that case, which drew the attention of Gov. Jeb Bush and the Legislature, relatives of Ms. Schiavo disagreed about her condition, and a brain-imaging test - once it has been standardized - could help determine whether brain damage has extinguished awareness."
Unfortunately, it is not clear by the current research study whether the activity seen on MRI does tell, if any, how much and what quality of awareness is present.
In relation to the Schiavo case, a patient clinically disgnosed as in a permanent vegetative state (PVS)(2), the study did not involve PVS patients. Therefore what immediate consequences this report has on this case is unknown. However, since much of the significance of this study is unknown and there is no current treatment to reverse the anatomic and functional damage in PVS or MCS, it is my opinion that this will not change the ethical decision based on substituted judgment and supported by the courts in that case. ..Maurice.
1. Minimally Conscious States: Patients in minimally conscious states posses sleep-wake cycles and limited, inconsistent but definite awareness of self and environment (e.g., avoiding unpleasant stimuli, uttering intelligible sounds or reaching for objects in a way that adjusts for their size and location)
2.Vegetative States: The Multi-Society Task Force on Persistent Vegetative State (PVS), which included representatives from many of America’s most prestigious neurology associations, has defined the vegetative state as a condition of complete unawareness of self and environment, accompanied by sleep-wake cycles and either total or partial preservation of areas of the brain controlling automatic functions like heart activity and reflexes. PVS patients may cry or smile but these actions are reflexive and do not reflect true awareness.
posted by Maurice Bernstein, M.D. @ 3:04:00 PM
5 comments
5 Comments:
As an abstract question (not related to the cases you've mentioned), are procedures performed on comatose or minimally conscious patients that are of no therapeutic value to the patient ethical? Does it matter whether the procedures are invasive or not? Does legal consent matter?
Dave, treatment which represents *comfort care* although not specific therapy for any patient's underlying disease is ethical and encouraged. Otherwise, procedures on *any* patient which are of no established therapeutic value, representing whatever risk with no benefit would be unethical. The procedure itself may be defined as "medically futile" if the procedure cannot provide any benefit and should not be performed. However, procedures may be carried out on any patient, where the benefit is unclear, as a medical research study, after full review and acceptance by an Institutional Review Board and full informed consent by the patient. Medical procedures may be invasive or not. The invasiveness generally relates to the risks.
Now with regard to comatose or minimally conscious patients (MCS), all of the above apply. However, in the case of MCS or those in a permanent vegetative state there may be ethical disagreement regarding the benefits. The main difference with these patients is the competency to give informed consent in the case of a procedure done as part of a medical research study. A legal surrogate must be fully informed and give consent. There is one exception. A research project may involves critically ill patients arriving in an emergency room where the patient may be incompetent to give consent at that time and the procedure must be urgently carried out as a potential life-saving act. Even though the procedure is experimental and may later be found not be of therapeutic value, federal law permits carrying out such as study without surrogate consent, requiring approval on a study by study basis.
I hope I have answered your questions. ..Maurice.
Absolutely. And that's the way I would have answered the questions myself. Now, going back to the case at hand, it would appear to me that it is very doubtful that the study cited in the article was conducted ethically.
Dave, I wonder why you think the study was done unethically. I read the actual Neurology article and it states that informed consent was obtained.
Here is the pertinent text about the subjects and consent:
"Control subjects and patients. Seven healthy volunteers
without history of neurologic disorders or chronic disease
were recruited according to institutional informed consent procedures
and performed language-related tasks similar to those performed
by the MCS patients. All subjects were right handed as
assessed by the Edinburgh Handedness Inventory One volunteer who was age and gender matched to the
patients also participated in a tactile study performed similarly to
the patients. Structural MRI revealed no abnormalities in any of
the healthy subjects.
Two right-handed male MCS patients, ages 21 (Patient 1) and
33 (Patient 2), were recruited for this study. Legally authorized
surrogates for both patients were contacted by medical personnel
not directly involved in the current studies. Informed consent was
obtained according to institutional guidelines on two occasions,
allowing for a period of evaluation and opportunity for additional
information."
The procedure appeared to hold no significant physical risks:
"A 1.5-T General Electric MR scanner (Milwaukee,
WI) was used to obtain T2*-weighted images with a gradient
echo pulse sequence that was sensitive to MR signal changes
induced by alteration in the proportion of deoxyhemoglobin in the
local vasculature accompanying neuronal activation..."
The tasks were benign:
"Tasks. Three passive stimulation tasks were performed: light
touch of both hands, auditory narratives of familiar events presented
by a familiar person, and the same auditory passages without
language-related content. Each condition was performed twice
for a total of six runs per subject. During the first two runs,
patients “listened” to a narrative prepared by a familiar relative
through headphones"
The only other possible ethical issue I can see is what was privately told to the legal surrogates of the patients by the researchers or by the patient's physicians when the results were known. Of course, this detail is not part of the study and was not included in the article. It would have been unethical to provide unsubstantiated hope to them if this was actually done. It is clear from the study and the background research that this type of MRI analysis is at this point hardly proven a tool for prognosis of brain trauma. ..Maurice.
You're absolutely right; I miseed that; I was wrong.
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