Signs of Consciousness

Jerome Groopman has an article in the Oct. 15 issue of the New Yorker. Medical Dispatch: Silent Minds: Reporting & Essays is about consciousness, particularly among those in various degrees of coma. Groopman reports on some fascinating work by the British neuroscientist Adrian Owen, who's used fMRI to demonstrate that some vegetative patients respond to language, some of whom show the "the same response to the sentences as scans of healthy volunteers." Once he and and his colleagues determined that one patient could distinguish language from noise sounds, they conducted tests to see if she would respond to mental imagery: when asked to imagine herself playing tennis, again her fMRI " 'activation [was] indistinguishable from those in the group of normal volunteers' "who had also been asked to imagine themselves playing tennis.

Groopman goes on to report on work that Lionel Naccache, a neurologist at the Hôpital Pitié-Salpêtrière in Paris, is doing to develop a medical definition of consciousness, which includes these three elements:

1. Ability to report the content of a representation ("I see my cat")
2. Ability to sustain this representation over time ("I still see my cat")
3. The ability to "broadcast" this information to other areas of the brain. (I think this would mean things like ... "I pet my cat" or "I must feed my cat"). Groopman describes some interesting work Naccache has done to show the importance of broadcasting.

Groopman also talks about work that Joseph Giacino, a neuropsychologist at New Jersey's J.F.K. Johnson Rehabilitation Institute is doing with "deep-pressure stimulation": Giacino would squeeze "patient's muscles with force and precision," after which a patient seemingly in a vegetative state began to talk and answer simple questions. Further work at the Institute uses brain-scan technology to help with diagnosis of patients who might respond to such therapy.

The article is packed with interesting case studies and some fascinating scientific, ethical, and philosophical questions. A related article in the May 2007 issue of Scientific American by Steven Laureys is interesting because Laureys has done similar work himself. The Sci Am article also points to an interesting book about the medical, ethical, and legal dilemmas raised by these breakthroughs.

For More Information

• Davis Matthew, Coleman Martin, Absalom Anthony, et al. Dissociating Speech Perception and Comprehension at Reduced Levels of Awareness. PNAS (the journal of the National Academy of Sciences) October 9, 2007, Vol. 104 no. 41, p. 16032-16037. (abstract only; full-text may be available @ your library)
  
• Groopman, Jerome. Medical Dispatch: Silent Minds: Reporting & Essays. New Yorker, October 15, 2007 (free online).
  
• Laureys, Steven. "Eyes Open, Brain Shut." Scientific American, May 2007, p. 86-89. (Full article at Academic Search Premier and other library databases)
• Jennett, Bryan. The Vegetative State: Medical Facts, Ethical and Legal Dilemmas. Cambridge University Press. 2002.
  
• Owen, Adrian, Coleman, Martin, Boly, Melanie et al. "Detecting Awareness in the Vegetative State." Science. September 8, 2006, Vol. 313. no. 5792, p. 1402. See also the many related commentaries in that issue of Science. (abstract only; full-text may be available @ your library)