This paper critically examines whether patients with severe brain injury, who can only communicate through assistive neuroimaging technologies, may permissibly participate in medical decisions. We examine this issue in the context of a unique case study from the Brain and Mind Institute at the University of Western Ontario. First, we describe how the standard approach to medical decision making might problematically exclude patients with communication impairments secondary to severe brain injury. Second, we present a modified approach to medical decision making. (...) We argue that this approach might warrant the inclusion of some patients with severe brain injury in low-stakes decisions, or to express preferences. Third, we present a model of supported decision making to address recalcitrant uncertainty. We conclude by suggesting that the modified approach to decision making and supported decision making might allow a patient with severe brain injury to participate in some medical decisions. Our analysis is provisional and has not yet been implemented in practice. Our discussion is intended to generate further debate on approaches to enhancing autonomy in patients with profound motor and cognitive impairments. (shrink)