This study aimed to assess similarities and differences in Canadian and German specialty physicians’ medical knowledge of the VS and attitudes toward ethical challenges in this disorder. This was the first such survey involving Canadian physicians. We found nearly identical rates of 80% for diagnostic accuracy in both samples and the subsamples of neurologists did not show greater accuracy rates than other physicians. Participants in both countries attributed a range of capabilities to patients in VS. The majority considered acceptable to limit life-sustaining treatment under certain circumstances. However, participants’ appraisals of ethical challenges differed between the countries.
Our findings indicate lower inaccuracy rates than the study by Schnakers and colleagues, who showed that 40% of the VS patients were misdiagnosed by doctors who had not used validated behavioral test instruments . That the majority of physicians who provided a wrong diagnosis were certain of their answer in our study, raises the question of whether this group would perceive a need for further training in this area as previously recommended . One of the most surprising findings of our study is the high proportion of participants in Canada and Germany who attributed capabilities to a patient in the VS akin to misattribution of capabilities observed in the public domain  (but contra Kickman and Wegner ). The key assumption underlying the traditional diagnosis of VS is the absence of awareness . However, a majority of participants disagreed over whether the patient could perceive pain, and a majority of German participants and a large proportion of Canadian participants disagreed over whether the patient could feel touch. These results are not unprecedented [12, 17, 24, 25], even if they sharply contrast to the medical understanding of the VS that is supported by fMRI research [26, 27]. The differences between the two samples could be explained by the higher proportion of participants with religious or spiritual beliefs in the German sample given studies that have reported effects of religious beliefs in the care of patients with disorders of consciousness [12, 13]. Another explanation might be that more German participants provide long-term care in the out-patient care setting and therefor might be able to observe more body expressions by patients in the VS in a rehabilitation process that could let them assume that such patients display capabilities inconsistent with common understandings of the diagnosis. The higher attribution of capabilities might lead to a higher reluctance to withdraw LST for patients in the VS.
Most Canadian participants identified long-term care placement as the most ethically challenging issue, perhaps because such facilities are rare in Canada. In a qualitative study, this issue and resource allocation were found to be important challenges in Canada . Finding long-term-care placement and evaluating resource allocation were not perceived as challenging by German participants and a potential explanation lies in a system in which patients have greater access to long-term care facilities such as nursing homes, specialized centers for patients with disorders of consciousness (rehabilitation phase F, long term care to maintain function, delivered in specialized units), and nursing homes for patients who require artificial respiration [29, 30]. These results are consistent with practice variations on different treatment measures reported previously [7, 31–33]. They also suggest the potential impact of institutional medical practice, health care system, legal regulations and religion, as factors influencing participants’ attitudes toward treatment limitation and ethical challenges for patients in the VS as found, for example, in large-scale studies of LST decisions in Europe [34, 35]. Although we can only speculate on the reasons for such variation (e.g., different culturally held moral traditions in either country) more Canadian participants favored always ceasing LST. One hypothesis, in line with recent research on the duality of moral theories , is that the attitudes of German participants, more reluctant to withdrawal of LST, may stem from a deontological philosophical tradition, where duties, rights and categorical principles of action have greater influence. The more rationalistic, utilitarian responses of Canadian participants may have led them to be more in favor of treatment limitation when the prognosis is unfavorable and chances for recovery are low. More specific data (e.g., on the preferred ethical theories of physicians in both countries) would be needed to test this hypothesis. A different explanation might link the history of serious ethical faults of the German medical profession under the Nazi regime  to the expression of prudental attitudes towards withdrawal of treatment for patients with severe disabilities. Acknowledging the existence of variation and seeking a clearer understanding of its causes are important steps to offer more coherent messages to family members and the public and to ensure a fair provision of treatment for patients with disorders of consciousness.
There was a small discrepancy in the case vignette (modification of one word, “consistently”, in the paper version of the Canadian questionnaire) for the sake of improved clarity. Our analysis of the Canadian data showed that it had no significant influence on the accuracy rate. Generalizability of the results of this long survey is limited by a focus on a single clinical condition and by a low response rate, especially in Canada, but we were able to gather representative samples of both German neurologists and Canadian physicians based on demographic variables. Individuals most likely excluded themselves from participation when they did not provide care for patients in the VS. The composition of the initial two samples differed in age, specialties represented, experience and physicians work setting, but the distributions of the experience with patients in the VS and gender were similar. These constitutive differences in the two cohorts could have influenced the described differences in the results. However, we compared subsamples of neurologists and found no differences in their accuracy rates. The original study design (e.g., recruitment strategy) was the same in both countries. Differences reported occurred because of adaptation to specific regulatory and institutional environments in the countries, such as policies of professional societies, availability of physicians’ addresses and willingness to respond.