To provide conceptual clarity regarding the distinctly non-causal nature of evidence and nosology typically brought to bear on disorders of consciousness (DoC), and suggest revisions to clinical classifications of consciousness based on ethical and philosophical analysis.

Accurately diagnosing DoC following brain injury remains clinically challenging. Rates of clinical misdiagnosis are high, at times leading to premature withdrawal of life-sustaining treatment and breakdowns of trust in caregiver-provider relationships. Such instances of diagnostic fallibility may be caused by a discrepancy in stakeholders’ conceptual understanding of consciousness and the limited nature of clinical nosology for DoC.

We performed a narrative review and normative analysis based on philosophical, ethical and clinical literature on diagnosing consciousness to critically evaluate two salient sources of diagnostic fallibility in evaluating DoC: (a) reliance on behavioral evidence of consciousness and (b) the imprecise and non-causal nature of DoC nosology.

Despite the decline of behaviorist theories of consciousness in psychology, ethics and philosophy, clinicians predominantly use behavioral tests to diagnose DoC, which preclude causal explanations about the etiology of disordered consciousness. Given the limited and non-causal nature of behavioral evidence typically used in DoC diagnosis, clinicians may form more accurate diagnoses by incorporating novel neurotechnology into the diagnostic process and directly observing the causal determinants of disordered consciousness. With the expansion of evidentiary methodology for assessing DoC, clinicians can begin to qualify existing diagnostic categories as behaviorally observed states (e.g. behavioral coma) while leveraging advances in neuroscientific research to craft a refined nosology that conveys more precise information about DoC and the structure of DoC determinations.

Evidentiary shortcomings in diagnosing DoC and their tacit philosophical underpinnings cause inaccurate diagnoses and subsequent miscommunication with families. These issues may be rectified by using advanced neurotechnology and refining diagnostic language to mend the inferential gap between evidence and diagnostic conclusions about consciousness.