“In the [vegetative state] or [minimally conscious state] the EEG is by definition not flat and typically shows widespread slowing of brain rhythms. Does this mean that nothing is being processed? The answer is a definite ‘no’. A clear analogy is the emerging literature on the depth of processing of environmental input (i.e., the surgeon talking about something in the operating room) while the patient is under anesthesia with widespread EEG slowing akin to that observed in VS and MCS. By this logic it would be surprising if some sensory input were not being processed in all VS patients and certainly in all MCS patients. By extension, one might also propose that some internal thoughts are being generated in these devastating clinical states.
Indeed, the key issue from the neurologist’s perspective is whether the neurological insult, whether prolong hypoxia or severe traumatic brain injury, will leave any meaningful brain function. So, it is not clear if the key issue is ‘consciousness’ or the clinical experience with these patients per long-term recovery of ‘meaningful’ life. Of course, meaningful is as poorly defined as consciousness and herein lies the quandary.”
~ Robert Knight, (2008) “Consciousness Unchained: Ethical Issues and the Vegetative and Minimally Conscious State” The American Journal of Bioethics, 8(9): 1–2