Susan is now showing evidence of purposeful interaction with her environment; she is in a minimally conscious state. Functional imaging is not required or recommended to make a diagnosis of minimal consciousness in a patient who meets clinical criteria on exam.

Functional imaging is limited by both technical factors and our current knowledge of its current interpretation. A study done at different times on the same patient could show activation of different areas based on the patient's own fluctuating awareness that day, so many not accurately identify functional integrity. Even if intact networks were identified, it would be unclear how robust a subjective experience of consciousness or self-awareness the radiographically observed activity actually reflected. The neurologist can inform the family that the patient has recovered some neurological function, but that she is severely brain-injured, based on her history and physical examination.

A passage from the newest edition of Plum and Posner is worth quoting here: "Families may want confirmitory studies to convince them of the solidity of the clinical diagnosis, trusting the 'objectivity' of the scan over the analysis of the clinician....Surrogates may invest imaging techniques with more diagnostic ability than they currently possess and seek clear-cut answers through this visual medium. It is important to be clear that the diagnosis of patients with disorders of consciousness is a clinical task informed by a competent history and neurological examination. Although desperate families may request them...neuroimaging studies are applied only in research settings and at best can be ancillary to clinical evaluation." (italics original.) ¹ That is to say that the results of neuroimaging and brain scans may inform a diagnosis, but they may not stand alone. The definitive diagnosis of a patient's state of consciousness must come from a professional neurological and physical examination of the patient.

¹ Posner JB, Saper CB, Schiff N, Plum F. Plum and Posner's Diagnosis of Stupor and Coma. USA: Oxford University Press; 2007.