Treatments to enhance recovery from the vegetative and minimally conscious states: ethical issues surrounding efficacy studies.

Randomized double-blind placebo-controlled trials have been argued to provide the strongest test of efficacy and, as such, are important tools for advancing the evidence base supporting rehabilitation treatment. However, such trials present difficult ethical issues, because one group, by definition, receives no treatment for the condition being studied. In the case of an experimental treatment that is available only within a research protocol, a 50% chance of receiving the desired treatment may be sufficient to motivate enrollment. However, many rehabilitation treatments that need further study are available outside of research protocols and are perceived as low risk, making the advantages of research participation less clear and the task of weighing the pros and cons of research participation more difficult. In this article, we discuss a placebo-controlled trial currently underway in which this issue is combined with a number of other complicating factors, such as the inability of study participants to provide their own informed consent, and the catastrophic nature of the disability under study. We examine whether other research designs could successfully answer efficacy questions in this area, and we discuss the ethical and psychosocial issues involved in planning the trial and seeking enrollment.