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by Drew Rosielle MD
Mon, Feb 08 2010, 05:11 PM
NEJM has a paper which pushes the last several years' worth of fMRI studies in patients in the PVS or MCS (persistent vegetative state; minimally conscious state) to the next level. (See here for other blog postings about this.) There have been a handful of reports in the last few years of patients clinically diagnosed as being in a PVS, who have some fMRI evidence of cortical activity (e.g. have 'normal' responses to hearing their name spoken, demonstrate normal cortical responses to instructions such as imagining they are playing tennis - by normal I mean show responses similar to healthy controls in that the appropriate areas of the motor cortex show increased activity, etc.). This study is builds on that, and the authors describe identifying one subject who could answer yes/no questions via fMRI.
Let me explain. First, the proof of principle. They had 16 healthy subjects imagine either playing tennis or walking around a familiar environment imaging what they'd see: reliably in these subjects these tasks would cause predictable, and predictably different, activity seen on fMRI (e.g. in the supplemental motor cortex for the motor task and in the parahippocampal gyrus for the spatial task). Then they told the subjects that they were to answer yes/no questions by, for instance, imagining the motor task for Yes and the spatial task for No. The healthy subjects could do this, and essentially they demonstrated you could use this technique to have people answer Y/N questions simply by having them imagine different things.
Next they tried the imaging tasks on 54 patients who were diagnosed as being in the PVS or MCS. 5 of them could do the imagining task (get results similar to the healthy subjects). Then they chose one patient to test the Y/N answering protocol (it is unclear to me why this specific patient was chosen or why they didn't investigate or didn't report their findings on the other four), and found that this patient could in fact give accurate Y/N answers to biographical questions (name of his father, etc.). He did this for 5/6 questions, repeatedly. This patient, a young man over 3 years out from a traumatic brain injury, was considered to be in a PVS (although the authors indicate some ambivalence about this - there seems to be some question if he was in a MCS: regardless, he was profoundly brain injured and would likely be considered by most to be in a PVS).
My thoughts on this: I think there is no doubt that the previously-established clinical diagnoses of PVS and MCS are going to be modified by this sort of information, and it seems apparent that a small percentage of patients diagnosed as being in a PVS actually have some cortical activity and awareness (on some level, in some way - see below). The sort of idea of the PVS being a 'clean,' homogeneous diagnostic and phenotypic category (no 'higher' cortical activity, no awareness of surroundings) clearly is wrong (at least for a few patients - this study would suggest 2-9%). However, until any of this translates into improved prognostic data (the ability to predict who, if anyone, has a chance of some recovery) or effective therapies are developed (perhaps aided by this technique to identify those patients like to benefit), the clinical situation hasn't really changed. And, as we've discussed on the blog before, the idea that there might be people misdiagnosed as being in the PVS doesn't change in any fundamental way the ethics of giving, withholding, or withdrawing life-prolonging medical treatments in these patients. The fundamental question remains would the patient her/himself want to be prolonged, with medical treatments, in such a state with such a prognosis, and allowing that that patient may have some awareness doesn't necessarily change one way or the other the decision-making. It might for some families/individuals, but not predictably. If you believe in the 'clean' PVS then you can argue that at least they're not suffering so why not continue; if you don't, then you have the added dilemma of a patient truly locked-in, unable to communicate thirst, pain, hunger, love, etc. and that's not necessarily 'better' than being 'vegetative.'
As perplexing and challenging as this research is, I think we have to keep this perspective at the forefront as these sorts of responses are inevitable. This research is important, and it might change things, but not in the way some automatically assume.
 Of course the logical extension of this technology is The Captain Pike scenario (for those few 'PVS' patients who can respond); those patients, if felt to be sufficiently decisional, could theoritically communicate their own wishes.
How one would determine that - and the gulf between answering 5 biographical Y/N questions and establishing that a patient is 'conscious,' is discussed in an associated editorial, which has a more detailed exploration of how we really don't know what any of this means yet. The mind is an emergent property of the brain and cannot be "seen" in images. The article by Monti et al is provocative; however, physicians and society are not ready for "I have brain activation, therefore I am." That would seriously put Descartes before the horse. (Image via Memory-Alpha.org, which uses a Creative Commons share-alike license.)
(Eric Widera at Geripal has also posted about this article; he has a nice summary of some of the media reporting, such as it is, about this paper.) 
by Drew Rosielle MD
Mon, Feb 08 2010, 02:00 PM
Archives of Internal Medicine recently had a study about the influence of nursing home culture on rates of tube feeding of patients with advanced dementia. This is a qualitative/ethnographic study of two NH in South Carolina, both within the same region, and both selected because one had very high rates of TF of patients with dementia (41%) and one had a low rate (11%) (they note the high one was actually the 4th highest in the region - the other 3 wouldn't participate in the study).
The researchers observed care in the NH (how mealtimes are structured, who does what, etc.) and interviewed multiple providers at each site (nurses, CNAs, speech pathologists, administrators, dieticians, etc.). There were important differences between the two nursing homes: the 'high use' NH had a larger proportion of African Americans (52% vs 9%), Medicaid patients (80% vs. 28%), no dementia unit, and poorer quality indicators (using CMS data). Both NH were part of for-profit chains.
As this is a qualitative study the findings are difficult to summarize, but generally come down to: the low-use facility was nicer, feeding was better staffed with better trained CNAs, and multi-disciplinary shared decision making was common. The article is a thrilling/appalling read as you hear the differences between the two NH:
Both NHs had interdisciplinary teams to identify and respond to residents' weight loss but differed on team composition and family role. The low-use NH team included the dietary technician, SLP, director of nursing, administrator, nurses, activity director, social worker, and on-staff physician. The physician evaluated residents who lost weight and discussed his findings with family. His attitude reflected a preference for hand feeding over tube feeding. He said, "I am subtly negative, or not so subtly. I tell [the family] that [a feeding tube] has no effect on mortality. It just changes the complications." The social worker also facilitated family meetings to determine how the options of hand feeding vs tube feeding aligned with the goals of care. The high-use NH team was composed of the dietary technician, SLP, and nurses. Nurses were responsible for notifying PCPs of weight loss, obtaining orders for nutritional supplements, and notifying families about feeding problems. The social worker denied having a role in feeding decisions. An NP reported that by the time she was consulted, "department heads" had already approached families to suggest tube feeding. The NP found it nearly impossible to "undo" family beliefs that feeding tubes were in residents' best interests. The NP reported that dehydrated residents were often admitted to the hospital and returned with feeding tubes.
Most of the paper is along these lines. As I started reading this, and saw the differences in demographics between the NH my initial response to this was that given the well-described increased use of FT in African Americans with dementia that their findings would be impossible to interpret beyond that (ie how do you say the differences they see cause the differences in FT rates as AA patients prefer and receive FT more often than white Americans). Instead I came away with more of a sense that the differences they describe could in part be the cause of the significant disparity in FT rates in different cultural groups in the US - particularly that poverty, and reliance on marginally financed safety net institutions with fewer staff with less training and an institutional culture of disengagement about these issues (as opposed to patient-centered engagement with, for instance, family meetings) drives the disparities. It's this abandonment of discussion and patient-centered decision-making that is what is most disheartening about the study, at least to me. Assessing values, discussing all options - getting 'true' informed consent - etc. just seemed to be absent from the high-use home. 
by Drew Rosielle MD
Mon, Feb 08 2010, 01:55 PM
I am in the process of preparing my house for sale, and for the next few weeks/month will be spending all my free time cleaning, recycling, painting, and worrying, and don't plan on posting again during that time. I have another couple posts written, which I've scheduled for a couple weeks from now, but that's it.
I will be at AAHPM in Boston, and hope to see many of you there. Come to the happy hour and say Hi, or just grab me if you run into me. --Drew.  
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