More Science See Inside New Technique Seeks to Measure Consciousness An electromagnetic gadget to measure the level of consciousness By Christof Koch MARCELLO MASSIMINI University of Milan Measure what is measurable, and make measurable what is not so. This quote from Galileo Galilei, one of the founding fathers of science, is a call to arms for ingenious bench scientists, clinicians and theoreticians to render consciousness measurable: to build an instrument that can tell whether that prone person who is nonresponsive or behaving in a reflexlike manner is actually conscious of something—of anything. Such a “consciousness meter” should reliably distinguish between a sleeper who is experiencing a vivid dream—even if she does not recall most of its content later on—and one who is in a dreamless, deep sleep, not feeling anything. Not just black but nothing, nichts, nada, rien. Or between a patient who is deeply anesthetized, and oblivious to the abdominal surgery being performed on him, and the rare cases of “awareness under anesthesia.” Such a device should also be able to tell whether a grievously brain-injured patient, whose electroencephalograph (EEG) might be flat but who is moaning and occasionally moving his head or limbs, is experiencing pain or distress or is truly not conscious—alive but oblivious to the world. This is only a preview. Get the rest of this article now! Select an option below: Buy Digital Issue Customer Sign In *You must have purchased this issue or have a qualifying subscription to access this content It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. Click here to access this article in its entirety through site license access. ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2015 Scientific American, a Division of Nature America, Inc. All Rights Reserved.