when you put pet scans in england, a doctor named adrian owens, he said 43% were constants. these are the people we have judged it to be unconscious. he had devised ways to communicate with them. through canvassers. her years, the families of these patients had said that our son or husband or whatever -- they seem very aware when people he likes comes in. you can tell from his expression. .. >> host: has been used experimentally where you have to imagine yourself playing tennis, and this activity, this is introduced again, technology introducing a whole other wrinkle into the conversations. >> guest: you should know though this technology is not used to test -- >> host: not used to test? >> guest: we're note going back to eegs. >> host: right, for reasons we'll come to, and that's an important point, and you'll emphasize that in the book, and if i understand you correctly, who would you leave it to or what process do you feel would be more appropriate? >> guest: well, i think what philip said, on an airplane, the captain comes over the intercom and says we have an emergency,

when they put pet scans on these people in england, that doctor named adrian owen, he found 43% of them are unconscious. these are people we have judged the unconscious and some of them have been in this thing for four years. he devised ways of communicating with them through hand busters. for years the families of these patients have said you know, our son or my husband or whatever seems very aware when people he likes come into the room. he lightens up and if there is a doctor he likes or doctor he doesn't like he can you can tell from his expression. this had all been pooh-poohed. they saw the patient more than he did. with this technology they found were conscious and another thing is conscious mri. it's ongoing lack of film almost and that can be -- detect consciousness but we are not using this technology to ferret out the people who are not really brain-dead. >> host: my impression is that minimally conscious state is certainly different from the persistent vegetative state. but you have taken that distinction into account. >> guest: oh yeah. it's much less closer to death in pbs